Liquid ejection device and drive circuit board

Abstract

To provide a liquid discharge device which can improve waveform accuracy of a driving signal and reference voltage signal supplied to a piezoelectric element.SOLUTION: In a liquid discharge device, a drive circuit substrate which outputs a first driving signal supplied to a first electrode includes a substrate, a first drive circuit which includes a first circuit element supplied with a ground potential on one end and outputs the first driving signal, a first capacitor which is electrically connected to a second electrode on one end and is supplied with the ground potential on the other end, and a second capacitor which is electrically connected to the second electrode on one end and is supplied with the ground potential on the other end. The substrate includes a first surface and a second surface. The first capacitor is a chip capacitor. The second capacitor is an electrolytic capacitor. The first circuit element and the first capacitor are arranged on the first surface. The second capacitor is arranged on the second surface.SELECTED DRAWING: Figure 16

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device and a drive circuit board. [Background technology]

[0002] Known liquid ejection devices that eject liquid include those that use a driving element such as a piezoelectric element. In such liquid ejection devices, the piezoelectric element is driven in response to the potential difference between a drive signal supplied to one end and a reference potential supplied to the other end, and ejects an amount of liquid corresponding to the drive of the piezoelectric element.

[0003] For example, Patent Document 1 discloses a liquid ejection device in which a drive signal is supplied to one end of a piezoelectric element and a reference voltage signal is supplied to the other end, causing the piezoelectric element to be driven by the potential difference between the drive signal and the reference voltage signal, thereby ejecting an amount of liquid according to the drive of the piezoelectric element. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-066051 Summary of the Invention [Problem to be solved by the invention]

[0005] In a liquid ejection device such as that described in Patent Document 1, if distortion occurs in the signal waveform of at least one of the drive signal and the reference voltage signal, the ejection accuracy of the liquid ejected from the liquid ejection device decreases. However, Patent Document 1 does not mention anything from the perspective of improving the waveform accuracy of the drive signal and the reference voltage signal supplied to the piezoelectric element, leaving room for improvement. [Means for solving the problem]

[0006] One aspect of the liquid ejection device according to the present invention is a liquid ejection head having a piezoelectric element driven by a first drive signal supplied to a first electrode and a reference voltage signal supplied to a second electrode, the liquid ejection head ejecting liquid by driving the piezoelectric element; a drive circuit board that outputs the first drive signal; Equipped with The drive circuit board includes: a substrate having a plurality of wiring layers; a first drive circuit including a first circuit element having one end supplied with a ground potential and outputting the first drive signal; a first capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; a second capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; and the substrate includes a first surface and a second surface different from the first surface; The first capacitor is a chip capacitor, The second capacitor is an electrolytic capacitor, the first circuit element and the first capacitor are provided on the first surface, The second capacitor is provided on the second surface. A liquid ejection device characterized by:

[0007] One aspect of the drive circuit board according to the present invention is a drive circuit board that has a piezoelectric element driven by a first drive signal supplied to a first electrode and a reference voltage signal supplied to a second electrode, and outputs the first drive signal to a liquid ejection head that ejects liquid by driving the piezoelectric element, a substrate having a plurality of wiring layers; a first drive circuit including a first circuit element having one end supplied with a ground potential and outputting the first drive signal; a first capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; a second capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; Equipped with the substrate includes a first surface and a second surface different from the first surface; The first capacitor is a chip capacitor, The second capacitor is an electrolytic capacitor, the first circuit element and the first capacitor are provided on the first surface, The second capacitor is provided on the second surface. A drive circuit board characterized by: [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a liquid ejection device. [Figure 2] FIG. 2 is a diagram illustrating a schematic configuration of a discharge unit. [Figure 3] 3A to 3C are diagrams showing examples of signal waveforms of drive signals COMA, COMB, and COMC. [Figure 4] FIG. 2 is a diagram illustrating a functional configuration of a drive signal selection circuit. [Figure 5] FIG. 10 is a diagram showing an example of the decoded content in the decoder. [Figure 6] FIG. 10 is a diagram showing an example of the configuration of a selection circuit corresponding to one ejection section. [Figure 7] 10A and 10B are diagrams for explaining the operation of a drive signal selection circuit. [Figure 8] FIG. 2 is a diagram illustrating a configuration of a drive circuit. [Figure 9] 1A and 1B are diagrams illustrating the structure of a liquid ejection module. [Figure 10] FIG. 2 is a diagram illustrating an example of the structure of a discharging module. [Figure 11] 11 is a cross-sectional view of the discharge module taken along line Aa in FIG. 10. FIG. [Figure 12] FIG. 2 is a diagram illustrating an example of the structure of a head driving module. [Figure 13] FIG. 4 is a diagram illustrating an example of an electrical connection relationship of a drive circuit board. [Figure 14] 3A and 3B are diagrams illustrating an example of a cross-sectional structure of a wiring board included in a drive circuit board. [Figure 15] FIG. 8 is a diagram showing an example of the configuration of a surface 831 of a wiring substrate. [Figure 16] FIG. 10 is a diagram showing an example of the configuration of a surface 832 of a wiring substrate. [Figure 17] FIG. 8 is a diagram showing an example of the configuration of a layer 841 of a wiring board. [Figure 18] FIG. 8 is a diagram showing an example of the configuration of a layer 842 of a wiring substrate. [Figure 19] FIG. 8 is a diagram showing an example of the configuration of a layer 843 of a wiring board. [Figure 20] FIG. 8 is a diagram showing an example of the configuration of a layer 844 of a wiring substrate. [Figure 21] FIG. 8 is a diagram showing an example of the configuration of a layer 845 of a wiring substrate. [Figure 22] 22 is a cross-sectional view of the wiring board when the wiring board is cut along line Bb shown in FIGS. 15 to 21. FIG. [Figure 23] FIG. 10 is a diagram showing an example of electrical connection relationships of a drive circuit board in a second embodiment. [Figure 24] 22 is a cross-sectional view of the wiring board of the third embodiment when the wiring board is cut along a line segment corresponding to line Bb shown in FIGS. 15 to 21. FIG. [Figure 25] 22 is a cross-sectional view of the wiring board of the fourth embodiment when the wiring board is cut along a line segment corresponding to line Bb shown in FIGS. 15 to 21. FIG. [Figure 26] 22 is a cross-sectional view of the wiring board of the fifth embodiment when the wiring board is cut along a line segment corresponding to line Bb shown in FIGS. 15 to 21. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present invention will be described below with reference to the drawings. The drawings used are for the convenience of explanation. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0010] 1. First embodiment 1.1 Configuration of the liquid ejection device Fig. 1 is a diagram showing a schematic configuration of a liquid ejection device 1. As shown in Fig. 1, the liquid ejection device 1 is a so-called line-type inkjet printer that forms a desired image on a medium P by ejecting ink at a desired timing onto the medium P being transported by a transport unit 4. Here, in the following description, the direction in which the medium P is transported will sometimes be referred to as the transport direction, and the width direction of the transported medium P will sometimes be referred to as the main scanning direction.

[0011] As shown in FIG. 1, the liquid ejection device 1 includes a control unit 2, a liquid container 3, a transport unit 4, and a plurality of ejection units 5.

[0012] The control unit 2 includes processing circuits such as a CPU (Central Processing Unit) and an FPGA (Field Programmable Gate Array), and storage circuits such as semiconductor memory. The control unit 2 outputs signals that control each element of the liquid ejection device 1 based on image data input from an external device such as a host computer (not shown) that is provided outside the liquid ejection device 1.

[0013] The liquid container 3 stores ink as an example of a liquid to be supplied to the ejection unit 5. Specifically, the liquid container 3 stores ink of a plurality of colors to be ejected onto the medium P, such as black, cyan, magenta, yellow, red, gray, etc.

[0014] The transport unit 4 has a transport motor 41 and a transport roller 42. A transport control signal Ctrl-T output by the control unit 2 is input to the transport unit 4. The transport motor 41 operates based on the input transport control signal Ctrl-T, and the transport roller 42 is rotationally driven in accordance with the operation of the transport motor 41. As a result, the medium P is transported along the transport direction.

[0015] Each of the multiple ejection units 5 has a head driving module 10 and a liquid ejection module 20. An image information signal IP output by the control unit 2 is input to the ejection unit 5, and ink stored in the liquid container 3 is supplied to the ejection unit 5. Then, based on the image information signal IP input from the control unit 2, the head driving module 10 controls the operation of the liquid ejection module 20, and the liquid ejection module 20 ejects the ink supplied from the liquid container 3 onto the medium P under the control of the head driving module 10.

[0016] In the liquid ejection device 1 of the first embodiment, the liquid ejection modules 20 included in each of the multiple ejection units 5 are positioned in a row along the main scanning direction so as to be equal to or wider than the width of the medium P. This enables the liquid ejection modules 20 to eject ink onto the entire widthwise area of ​​the medium P being transported. In other words, the liquid ejection device 1 of the first embodiment is a so-called line-type inkjet printer in which the multiple liquid ejection modules 20, positioned in a row so as to be equal to or wider than the width of the medium P, eject ink as the medium P is transported, thereby forming a desired image on the medium P. Note that the liquid ejection device 1 is not limited to a line-type inkjet printer, and may also be a so-called serial-type inkjet printer in which the liquid ejection modules 20 form a desired image on the medium P by moving back and forth along the width direction of the medium P in the main scanning direction and ejecting ink onto the medium P being transported in synchronization with the reciprocating movement.

[0017] Next, the schematic configuration of the discharge unit 5 will be described. Here, the multiple discharge units 5 that the liquid discharge device 1 has all have the same configuration, and the following explanation will focus on only one discharge unit 5. FIG. 2 is a diagram showing the schematic configuration of the discharge unit 5. As shown in FIG. 2, the discharge unit 5 has a head driving module 10 and a liquid discharge module 20. In the discharge unit 5, the head driving module 10 and the liquid discharge module 20 are electrically connected by a connection member 30.

[0018] The connection member 30 is a flexible member for electrically connecting the head driving module 10 and the liquid ejection module 20, and may be, for example, a flexible printed circuit (FPC) or a flexible flat cable (FFC). Note that, as the connection member 30, a BtoB (Board to Board) connector may be used instead of an FPC or FFC, or a BtoB connector may be used in combination with an FPC or FFC.

[0019] The head driving module 10 includes a control circuit 100, driving signal output circuits 50-1 to 50-m, a reference voltage output circuit 53, and a conversion circuit 120.

[0020] The control circuit 100 includes a CPU, an FPGA, etc. An image information signal IP output by the control unit 2 is input to the control circuit 100. The control circuit 100 outputs signals for controlling each element of the discharge unit 5 based on the input image information signal IP.

[0021] The control circuit 100 generates a base data signal dDATA for controlling the operation of the liquid ejection module 20 based on the image information signal IP and outputs it to the conversion circuit 120. The conversion circuit 120 converts the base data signal dDATA into a differential signal such as LVDS (Low Voltage Differential Signaling) and outputs it to the liquid ejection module 20 as a data signal DATA. The conversion circuit 120 may convert the base data signal dDATA into a differential signal of a high-speed transfer method other than LVDS, such as LVPECL (Low Voltage Positive Emitter Coupled Logic) or CML (Current Mode Logic), and output it to the liquid ejection module 20 as a data signal DATA. The conversion circuit 120 may also convert a part or all of the input base data signal dDATA into a predetermined single-ended signal and output it to the liquid ejection module 20 as a data signal DATA.

[0022] The control circuit 100 also outputs base drive signals dA1, dB1, and dC1 to the drive signal output circuit 50-1. The drive signal output circuit 50-1 has drive circuits 52a, 52b, and 52c. The base drive signal dA1 is input to the drive circuit 52a. The drive circuit 52a performs digital-to-analog conversion on the input base drive signal dA1, and then performs class D amplification to generate a drive signal COMA1, which is output to the liquid ejection module 20. The base drive signal dB1 is input to the drive circuit 52b. The drive circuit 52b performs digital-to-analog conversion on the input base drive signal dB1, and then performs class D amplification to generate a drive signal COMB1, which is output to the liquid ejection module 20. The base drive signal dC1 is input to the drive circuit 52c. The drive circuit 52c performs digital / analog conversion on the input basic drive signal dC1, and then performs class D amplification to generate a drive signal COMC1, which is output to the liquid ejection module 20.

[0023] Here, it is sufficient for each of the drive circuits 52a, 52b, and 52c to generate the drive signals COMA1, COMB1, and COMC1 by amplifying the waveforms defined by the input reference drive signals dA1, dB1, and dC1, respectively. Therefore, each of the drive circuits 52a, 52b, and 52c may include a class A amplifier circuit, a class B amplifier circuit, or a class AB amplifier circuit, instead of or in addition to a class D amplifier circuit. Furthermore, in the following description, it is assumed that each of the reference drive signals dA1, dB1, and dC1 is a digital signal, but it is sufficient for the reference drive signals dA1, dB1, and dC1 to be analog signals as long as they can define the waveforms of the corresponding drive signals COMA1, COMB1, and COMC1.

[0024] The drive signal output circuits 50-2 to 50-m have the same configuration as the drive signal output circuit 50-1, except for the signals they input and output. That is, the drive signal output circuits 50-j (j is any of 1 to m) include circuits corresponding to the drive circuits 52a, 52b, and 52c, respectively. The drive signal output circuit 50-j generates drive signals COMAj, COMBj, and COMCj based on the basic drive signals dAj, dBj, and dCj input from the control circuit 100, and outputs them to the liquid ejection module 20.

[0025] Here, the drive signal output circuit 50-1 and the drive signal output circuits 50-2 to 50-m have the same configuration, and when there is no need to distinguish between them, they may be simply referred to as the drive signal output circuit 50. In this case, the drive signal output circuit 50 will be described as including drive circuits 52a, 52b, and 52c, with the drive circuit 52a outputting a drive signal COMA, the drive circuit 52b outputting a drive signal COMB, and the drive circuit 52c outputting a drive signal COMC.

[0026] Furthermore, the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50 all have the same configuration, and when there is no need to distinguish between them, they may be simply referred to as drive circuits 52. In this case, the drive circuit 52 will be described as generating a drive signal COM based on the basic drive signal do and outputting the generated drive signal COM to the liquid ejection module 20.

[0027] On the other hand, when describing the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50-1 separately from the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50-j, the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50-1 may be referred to as drive circuits 52a1, 52b1, and 52c1, respectively, and the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50-j may be referred to as drive circuits 52aj, 52bj, and 52cj, respectively. Specific examples of the configuration of the drive circuits 52 will be described later.

[0028] The reference voltage output circuit 53 generates a reference voltage signal VBS indicating a reference potential for driving a piezoelectric element 60 (described later) possessed by the liquid discharging module 20, and outputs the signal to the liquid discharging module 20. This reference voltage signal VBS is a signal of a constant potential, such as 5.5 V or 6 V. Here, the constant potential signal includes cases where the signal can be considered to be a constant potential when various variations and errors are taken into consideration, such as variations in potential caused by the operation of peripheral circuits, variations in potential caused by variations in circuit elements, and variations in potential caused by the temperature characteristics of circuit elements.

[0029] The liquid ejection module 20 includes a restoration circuit 220 and ejection modules 23-1 to 23-m.

[0030] A data signal DATA is input to the restoration circuit 220. The restoration circuit 220 restores the input data signal DATA, which is a differential signal, to a single-ended signal, separates the restored single-ended signal into signals corresponding to the respective discharge modules 23-1 to 23-m, and outputs the signals to the corresponding discharge modules 23-1 to 23-m.

[0031] Specifically, the restoration circuit 220 restores and separates the data signal DATA to generate a clock signal SCK1, a print data signal SI1, and a latch signal LAT1, and outputs them to the ejection module 23-1. The restoration circuit 220 also restores and separates the data signal DATA to generate a clock signal SCKj, a print data signal SIj, and a latch signal LATj, and outputs them to the ejection module 23-j. Note that any of the clock signals SCK1 to SCKm, print data signals SI1 to SIm, and latch signals LAT1 to LATm corresponding to each of the ejection modules 23-1 to 23-m output by the restoration circuit 220 may be input in common to the ejection modules 23-1 to 23-m.

[0032] Here, considering that the restoration circuit 220 restores and separates the data signal DATA to generate the clock signals SCK1-SCKm, the print data signals SI1-SIm, and the latch signals LAT1-LATm, the data signal DATA output by the conversion circuit 120 is a differential signal including signals corresponding to the clock signals SCK1-SCKm, the print data signals SI1-SIm, and the latch signals LAT1-LATm. Therefore, the original data signal dDATA output by the control circuit 100 includes single-ended signals corresponding to the clock signals SCK1-SCKm, the print data signals SI1-SIm, and the latch signals LAT1-LATm, respectively. In other words, the control circuit 100 outputs the original data signal dDATA as a signal for controlling the operation of the ejection modules 23-1-23-m of the liquid ejection module 20.

[0033] The discharge module 23-1 has a drive signal selection circuit 200 and a plurality of discharge units 600. Each of the plurality of discharge units 600 includes a piezoelectric element 60. That is, the discharge module 23-1 has a plurality of piezoelectric elements 60, the number of which is the same as the number of discharge units 600.

[0034] The ejection module 23-1 receives drive signals COMA1, COMB1, and COMC1, a reference voltage signal VBS, a clock signal SCK1, a print data signal SI1, and a latch signal LAT1. The drive signals COMA1, COMB1, and COMC1, the clock signal SCK1, the print data signal SI1, and the latch signal LAT1 are input to a drive signal selection circuit 200 included in the ejection module 23-1. The drive signal selection circuit 200 generates a drive signal VOUT by selecting or deselecting each of the drive signals COMA1, COMB1, and COMC1 based on the input clock signal SCK1, the print data signal SI1, and the latch signal LAT1. The drive signal selection circuit 200 then supplies the generated drive signal VOUT to one end of the piezoelectric element 60 included in the corresponding ejection section 600. The other end of the piezoelectric element 60 is supplied with the reference voltage signal VBS. The piezoelectric element 60 is driven by the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBS supplied to the other end, and as a result, an amount of ink corresponding to the drive amount of the piezoelectric element 60 is ejected from the corresponding ejection section 600.

[0035] Similarly, the ejection module 23-j has a drive signal selection circuit 200 and a plurality of ejection units 600. Each of the plurality of ejection units 600 includes a piezoelectric element 60. That is, the ejection module 23-j has a plurality of piezoelectric elements 60, the number of which is the same as the number of the ejection units 600.

[0036] The ejection module 23-j receives the drive signals COMAj, COMBj, and COMCj, the reference voltage signal VBSj, the clock signal SCKj, the print data signal SIj, and the latch signal LATj. The drive signals COMAj, COMBj, and COMCj, the clock signal SCKj, the print data signal SIj, and the latch signal LATj are input to a drive signal selection circuit 200 included in the ejection module 23-j. The drive signal selection circuit 200 generates a drive signal VOUT by selecting or deselecting each of the drive signals COMAj, COMBj, and COMCj based on the input clock signal SCKj, the print data signal SIj, and the latch signal LATj. The drive signal selection circuit 200 then supplies the generated drive signal VOUT to one end of the piezoelectric element 60 included in the corresponding ejection section 600. The other end of the piezoelectric element 60 is supplied with the reference voltage signal VBS. The piezoelectric element 60 is driven by the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBS supplied to the other end, and as a result, an amount of ink corresponding to the drive amount of the piezoelectric element 60 is ejected from the corresponding ejection section 600.

[0037] As described above, in the liquid ejection device 1, the control unit 2 controls the transport of the medium P by the transport unit 4 based on image data supplied from a host computer (not shown) or the like, and also controls the operation of the head drive module 10 included in each of the multiple ejection units 5, thereby controlling the ejection of ink from the liquid ejection module 20. In this way, the liquid ejection device 1 can cause a desired amount of ink to land at a desired position on the medium P. In this way, a desired image is formed on the medium P.

[0038] Here, the discharge modules 23-1 to 23-m included in the liquid discharge module 20 have the same configuration and only differ in the signals input thereto. Therefore, in the following description, when there is no need to distinguish between the discharge modules 23-1 to 23-m, they may be simply referred to as discharge modules 23. In this case, the drive signals COMA1 to COMAm input to the discharge modules 23 may be referred to as drive signals COMA, the drive signals COMB1 to COMBm as drive signals COMB, the drive signals COMC1 to COMCm as drive signals COMC, the clock signals SCK1 to SCKm as clock signals SCK, the print data signals SI1 to SIm as print data signals SI, and the latch signals LAT1 to LATm as latch signals LAT.

[0039] 1.2 Functional configuration of the drive signal selection circuit Next, we will explain the configuration and operation of the drive signal selection circuit 200 that the discharge module 23 has. In explaining the configuration and operation of the drive signal selection circuit 200 that the discharge module 23 has, first, we will explain an example of the signal waveforms included in the drive signals COMA, COMB, and COMC input to the drive signal selection circuit 200.

[0040] 3 is a diagram showing an example of the signal waveforms of the drive signals COMA, COMB, and COMC. As shown in Fig. 3, the drive signal COMA includes a trapezoidal waveform Adp arranged in a period T from when the latch signal LAT rises to when the next latch signal LAT rises. The trapezoidal waveform Adp is a signal waveform that, when supplied to one end of the piezoelectric element 60, drives the piezoelectric element 60 so that a predetermined amount of ink is ejected from the corresponding ejection portion 600.

[0041] The drive signal COMB includes a trapezoidal waveform Bdp arranged at a period T. The trapezoidal waveform Bdp is a signal waveform having a smaller voltage amplitude than the trapezoidal waveform Adp, and when the trapezoidal waveform Bdp is supplied to one end of the piezoelectric element 60, it causes the ejection section 600 corresponding to that piezoelectric element 60 to eject a smaller amount of ink than a predetermined amount. In other words, when the trapezoidal waveform Bdp is supplied to one end of the piezoelectric element 60, it is a signal waveform that drives the piezoelectric element 60 so that the corresponding ejection section 600 ejects a smaller amount of ink than a predetermined amount.

[0042] Here, the amount of ink ejected from the corresponding ejection section 600 when the drive signal COMA is supplied to the piezoelectric element 60 is greater than the amount of ink ejected from the corresponding ejection section 600 when the drive signal COMB is supplied to the piezoelectric element 60, and therefore the drive amount of the piezoelectric element 60 when the drive signal COMA is supplied to the piezoelectric element 60 is greater than the drive amount of the piezoelectric element 60 when the drive signal COMB is supplied to the piezoelectric element 60. In other words, the amount of ink ejected from the ejection section 600 corresponding to the piezoelectric element 60 when the drive signal COMA is supplied to the piezoelectric element 60 is different from the amount of ink ejected from the ejection section 600 corresponding to the piezoelectric element 60 when the drive signal COMB is supplied to the piezoelectric element 60; the amount of ink ejected from the ejection section 600 corresponding to the piezoelectric element 60 when the drive signal COMA is supplied to the piezoelectric element 60 is greater than the amount of ink ejected from the ejection section 600 corresponding to the piezoelectric element 60 when the drive signal COMB is supplied to the piezoelectric element 60; therefore, the amount of current generated by the propagation of the drive signal COMA is greater than the amount of current generated by the propagation of the drive signal COMB.

[0043] The drive signal COMC also includes a trapezoidal waveform Cdp arranged at a period T. The trapezoidal waveform Cdp is a signal waveform whose voltage amplitude is smaller than those of the trapezoidal waveforms Adp and Bdp, and when the trapezoidal waveform Cdp is supplied to one end of the piezoelectric element 60, it vibrates the ink near the nozzle opening to an extent that ink is not ejected from the ejection section 600 corresponding to that piezoelectric element 60. In other words, when the trapezoidal waveform Cdp is supplied to one end of the piezoelectric element 60, it drives the piezoelectric element 60 to an extent that ink is not ejected from the corresponding ejection section 600. This trapezoidal waveform Cdp vibrates the ink near the nozzle opening of the ejection section 600 including the piezoelectric element 60. As a result, the risk of an increase in ink viscosity near the corresponding nozzle opening is reduced.

[0044] As described above, the drive signals COMA and COMB drive the corresponding piezoelectric elements 60 so that ink is ejected from the ejection portions 600, and the drive signal COMC drives the corresponding piezoelectric elements 60 so that ink is not ejected from the ejection portions 600. In other words, the drive amount of the piezoelectric elements 60 when the drive signals COMA and COMB are supplied to the piezoelectric elements 60 is greater than the drive amount of the piezoelectric elements 60 when the drive signal COMC is supplied to the piezoelectric elements 60. Therefore, the voltage amplitude of the drive signals COMA and COMB is greater than the voltage amplitude of the drive signal COMC, and the amount of current generated in conjunction with the propagation of the drive signals COMA and COMB is greater than the amount of current generated in conjunction with the propagation of the drive signal COMC.

[0045] Furthermore, at the start and end timings of each of the trapezoidal waveforms Adp, Bdp, and Cdp, the voltage value of each of the trapezoidal waveforms Adp, Bdp, and Cdp is a common voltage Vc. That is, the trapezoidal waveforms Adp, Bdp, and Cdp are signal waveforms that each start and end at voltage Vc.

[0046] In the following description, the amount of ink ejected from the ejection section 600 corresponding to a piezoelectric element 60 when the trapezoidal waveform Adp is supplied to one end of the piezoelectric element 60 may be referred to as a large amount, and the amount of ink ejected from the ejection section 600 corresponding to the piezoelectric element 60 when the trapezoidal waveform Bdp is supplied to one end of the piezoelectric element 60 may be referred to as a small amount different from the large amount. Also, vibrating the ink near the nozzle opening to such an extent that ink is not ejected from the ejection section 600 corresponding to the piezoelectric element 60 when the trapezoidal waveform Cdp is supplied to one end of the piezoelectric element 60 may be referred to as micro-vibration BSD.

[0047] That is, in the liquid ejection device 1 of the first embodiment, the drive circuit 52a outputs a drive signal COMA that drives the piezoelectric element 60 so that the ejection section 600 of the ejection module 23 ejects a predetermined, large amount of ink, the drive circuit 52b outputs a drive signal COMB that drives the piezoelectric element 60 so that the ejection section 600 of the ejection module 23 ejects a small amount of ink that is less than the predetermined amount, and the drive circuit 52c outputs a drive signal COMC that drives the piezoelectric element 60 so that the ejection section 600 of the ejection module 23 does not eject ink. In other words, when the drive signal COMA is supplied to the piezoelectric element 60, a large amount of liquid is ejected from the corresponding ejection section 600, and when the drive signal COMB is supplied to the piezoelectric element 60, a small amount of ink different from the large amount is ejected from the corresponding ejection section 600.

[0048] 3, various signal waveforms may be used depending on the type of ink ejected from the ejection unit 600, the number of piezoelectric elements 60 driven by the drive signals COMA, COMB, COMC, the length of the wiring through which the drive signals COMA, COMB, COMC are transmitted, and the like. Therefore, the drive signals COMA1 to COMAm may each have a signal waveform of a different shape, and the amount of ink ejected from the corresponding ejection unit 600 by the drive signal COMA1 may be different from the amount of ink ejected from the corresponding ejection unit 600 by the drive signal COMAj. Similarly, the drive signals COMB1 to COMBm may each have a signal waveform of a different shape, and the amount of ink ejected from the corresponding ejection unit 600 by the drive signal COMB1 may be different from the amount of ink ejected from the corresponding ejection unit 600 by the drive signal COMBj. Similarly, the drive signals COMC1 to COMCm may each have a signal waveform with a different shape, and the amount of displacement of the piezoelectric element 60 caused by the drive signal COMC1 may differ from the amount of displacement of the piezoelectric element 60 caused by the drive signal COMCj.

[0049] Next, the configuration and operation of the drive signal selection circuit 200 that outputs the drive signal VOUT by selecting or deselecting each of the drive signals COMA, COMB, and COMC will be described. Fig. 4 is a diagram showing the functional configuration of the drive signal selection circuit 200. As shown in Fig. 4, the drive signal selection circuit 200 includes a selection control circuit 210 and a plurality of selection circuits 230.

[0050] A print data signal SI, a latch signal LAT, and a clock signal SCK are input to the selection control circuit 210. The selection control circuit 210 also has n sets of shift registers (S / R) 212, latch circuits 214, and decoders 216, each corresponding to one of the n ejection units 600. That is, the drive signal selection circuit 200 includes n shift registers 212, n latch circuits 214, and n decoders 216, the same number as the n ejection units 600.

[0051] The print data signal SI is a signal synchronized with the clock signal SCK, and includes 2-bit print data [SIH, SIL] for specifying the dot size formed by ink ejected from each of the n ejection units 600 as one of "large dot LD," "small dot SD," "non-ejection ND," and "slight vibration BSD." This print data signal SI is held in the shift register 212 corresponding to the ejection unit 600 for each 2-bit print data [SIH, SIL].

[0052] Specifically, the n shift registers 212 corresponding to the ejection units 600 are cascaded together. The 2-bit print data [SIH, SIL] included in the print data signal SI is sequentially transferred to the subsequent stages of the cascaded shift registers 212 in accordance with the clock signal SCK. When the supply of the clock signal SCK stops, the n shift registers 212 hold the 2-bit print data [SIH, SIL] corresponding to the ejection unit 600 corresponding to that shift register 212. Note that in FIG. 4, in order to distinguish the n cascaded shift registers 212, they are illustrated as 1st stage, 2nd stage, ..., nth stage from the upstream side where the print data signal SI is input to the downstream side.

[0053] Each of the n latch circuits 214 simultaneously latches the 2-bit print data [SIH, SIL] held in the corresponding shift register 212 at the rising edge of the latch signal LAT.

[0054] The 2-bit print data [SIH, SIL] latched by the latch circuit 214 is input to the corresponding decoder 216. Each of the n decoders 216 decodes the input 2-bit print data [SIH, SIL] and outputs selection signals S1, S2, and S3 with logic levels corresponding to the decoded content every period T. FIG. 5 is a diagram showing an example of the decoded content in the decoder 216. The decoder 216 outputs selection signals S1, S2, and S3 with logic levels defined by the input 2-bit print data [SIH, SIL] and the decoded content shown in FIG. 5. For example, if the 2-bit print data [SIH, SIL] input to the decoder 216 is [1, 0], the decoder 216 sets the logic levels of the selection signals S1, S2, and S3 to L, H, and L levels, respectively, during period T.

[0055] Returning to FIG. 4 , a selection circuit 230 is provided corresponding to each of the n discharge units 600. That is, the drive signal selection circuit 200 has n selection circuits 230. The selection circuits 230 receive selection signals S1, S2, S3 and drive signals COMA, COMB, COMC output by the decoder 216 corresponding to the same discharge unit 600. The selection circuits 230 select or deselect each of the drive signals COMA, COMB, COMC based on the selection signals S1, S2, S3 to generate a drive signal VOUT and output it to the corresponding discharge unit 600.

[0056] Fig. 6 is a diagram showing an example of the configuration of the selection circuit 230 corresponding to one discharge section 600. As shown in Fig. 6, the selection circuit 230 has inverters 232a, 232b, and 232c, and transfer gates 234a, 234b, and 234c.

[0057] The selection signal S1 is input to the positive control terminal (not marked with a circle) of the transfer gate 234a, and is also logically inverted by the inverter 232a and input to the negative control terminal (marked with a circle) of the transfer gate 234a. The drive signal COMA is input to the input terminal of the transfer gate 234a. When the input selection signal S1 is at H level, the transfer gate 234a establishes conduction between the input terminal and the output terminal, and when the input selection signal S1 is at L level, the transfer gate 234a establishes non-conduction between the input terminal and the output terminal. In other words, when the selection signal S1 is at H level, the transfer gate 234a outputs the drive signal COMA to the output terminal, and when the selection signal S1 is at L level, the transfer gate 234a does not output the drive signal COMA to the output terminal.

[0058] The selection signal S2 is input to a positive control terminal (not marked with a circle) of the transfer gate 234b, and is also logically inverted by the inverter 232b and input to a negative control terminal (marked with a circle) of the transfer gate 234b. The drive signal COMB is input to the input terminal of the transfer gate 234b. When the input selection signal S2 is at a high level, the transfer gate 234b establishes electrical continuity between its input terminal and output terminal, and when the input selection signal S2 is at a low level, the transfer gate 234b establishes electrical continuity between its input terminal and output terminal. That is, when the selection signal S2 is at a high level, the transfer gate 234b outputs the drive signal COMB to the output terminal, and when the selection signal S2 is at a low level, the transfer gate 234b does not output the drive signal COMB to the output terminal.

[0059] The selection signal S3 is input to the positive control terminal (not marked with a circle) of the transfer gate 234c, and is also logically inverted by the inverter 232c and input to the negative control terminal (marked with a circle) of the transfer gate 234c. The drive signal COMC is also input to the input terminal of the transfer gate 234c. When the input selection signal S3 is at a high level, the transfer gate 234c establishes electrical continuity between its input terminal and output terminal, and when the input selection signal S3 is at a low level, the transfer gate 234c establishes electrical continuity between its input terminal and output terminal. That is, when the selection signal S3 is at a high level, the transfer gate 234c outputs the drive signal COMC to the output terminal, and when the selection signal S3 is at a low level, the transfer gate 234c does not output the drive signal COMC to the output terminal.

[0060] In the selection circuit 230, the output terminals of the transfer gates 234a, 234b, and 234c are commonly connected. That is, the drive signals COMA, COMB, and COMC selected or not selected by the selection signals S1, S2, and S3 are output from the output terminals of the commonly connected transfer gates 234a, 234b, and 234c. The drive signal selection circuit 200 then supplies the signals from the output terminals of the transfer gates 234a, 234b, and 234c as drive signals VOUT to the piezoelectric elements 60 of the corresponding ejection units 600.

[0061] The operation of the drive signal selection circuit 200 configured as described above will now be described. FIG. 7 is a diagram illustrating the operation of the drive signal selection circuit 200. The print data signal SI is a signal that includes 2-bit print data [SIH, SIL] serially, and is input to the drive signal selection circuit 200 in synchronization with the clock signal SCK. The 2-bit print data [SIH, SIL] included in the print data signal SI is then sequentially transferred to the subsequent shift register 212 in synchronization with the clock signal SCK. Thereafter, when the input of the clock signal SCK stops, the 2-bit print data [SIH, SIL] corresponding to each of the ejection units 600 is held in the shift register 212 corresponding to the same ejection unit 600.

[0062] Thereafter, when the latch signal LAT rises, the latch circuit 214 simultaneously latches the 2-bit print data [SIH, SIL] held in the shift register 212. Note that in Fig. 7, the 2-bit print data [SIH, SIL] latched by the latch circuit 214 and corresponding to the 1st, 2nd, ..., nth stages of the shift register 212 are illustrated as LT1, LT2, ..., LTn.

[0063] The 2-bit print data [SIH, SIL] latched by the latch circuit 214 is input to the decoder 216. The decoder 216 outputs selection signals S1, S2, and S3 at logic levels corresponding to the dot size defined by the input 2-bit print data [SIH, SIL].

[0064] Specifically, when the input 2-bit print data [SIH, SIL] is [1, 1], the decoder 216 outputs the logic levels of the selection signals S1, S2, and S3 as H, L, and L levels to the selection circuit 230 during the period T. As a result, the selection circuit 230 selects the trapezoidal waveform Adp during the period T. This causes the drive signal selection circuit 200 to output the drive signal VOUT corresponding to the "large dot LD" shown in FIG.

[0065] Furthermore, when the input 2-bit print data [SIH, SIL] is [1, 0], the decoder 216 outputs the logic levels of the selection signals S1, S2, and S3 as L, H, and L levels to the selection circuit 230 during the period T. As a result, the selection circuit 230 selects the trapezoidal waveform Bdp during the period T. This causes the drive signal selection circuit 200 to output a drive signal VOUT corresponding to the "small dot SD" shown in FIG.

[0066] Furthermore, when the input 2-bit print data [SIH, SIL] is [0, 1], the decoder 216 outputs the logic levels of the selection signals S1, S2, and S3 as L, L, L levels to the selection circuit 230 during the period T. As a result, the selection circuit 230 does not select any of the trapezoidal waveforms Adp, Bdp, and Cdp during the period T. This causes the drive signal selection circuit 200 to output a drive signal VOUT corresponding to "non-ejection ND" shown in FIG.

[0067] Here, when the selection circuit 230 does not select any of the trapezoidal waveforms Adp, Bdp, and Cdp, the voltage Vc that was previously supplied to the corresponding piezoelectric element 60 is held at one end of the piezoelectric element 60 by the capacitive component of the piezoelectric element 60. In other words, when the drive signal selection circuit 200 outputs a constant drive signal VOUT at voltage Vc, this includes the case where the previous voltage Vc held by the capacitive component of the piezoelectric element 60 is supplied to the piezoelectric element 60 as the drive signal VOUT when none of the trapezoidal waveforms Adp, Bdp, and Cdp is selected as the drive signal VOUT.

[0068] Furthermore, when the input 2-bit print data [SIH, SIL] is [0, 0], the decoder 216 outputs the logic levels of the selection signals S1, S2, and S3 as L, L, and H levels to the selection circuit 230 during the period T. As a result, the selection circuit 230 selects the trapezoidal waveform Cdp during the period T. This causes the drive signal selection circuit 200 to output a drive signal VOUT corresponding to the "micro vibration BSD" shown in FIG.

[0069] As described above, the drive signal selection circuit 200 selects or deselects the drive signals COMA, COMB, and COMC based on the print data signal SI, the latch signal LAT, and the clock signal SCK, thereby generating drive signals VOUT corresponding to each of the multiple ejection units 600 and outputting them to the corresponding ejection units 600. This allows the amount of ink ejected from each of the multiple ejection units 600 to be individually controlled.

[0070] Furthermore, in the liquid ejection device 1 of the first embodiment, when large dots are formed on the medium P, the drive signal selection circuit 200 supplies the drive signal COMA output by the drive circuit 52a to the ejection unit 600 as the drive signal VOUT. When small dots are formed on the medium P, the drive signal selection circuit 200 supplies the drive signal COMB output by the drive circuit 52b to the ejection unit 600 as the drive signal VOUT. That is, the drive signal selection circuit 200 selects either the drive signal COMA or COMB depending on the size of the dots to be formed on the medium P. Therefore, the waveform cycle of the drive signals COMA and COMB can be shortened compared to a configuration in which one drive signal includes multiple signal waveforms and the size of the dots to be formed on the medium P is determined by selecting the signal waveforms in a time-division manner. As a result, the image formation speed at which the liquid ejection device 1 forms a desired image on the medium P can be increased.

[0071] Furthermore, in the liquid ejection device 1 of the first embodiment, in addition to the drive signals COMA and COMB, the drive signal COMC that drives the piezoelectric element 60 so as not to eject ink onto the medium P is included, thereby reducing the risk of ejection abnormalities occurring in the ejection section 600 due to increased ink viscosity, without reducing the image formation speed at which a desired image is formed on the medium P. In other words, in the liquid ejection device 1 of the first embodiment, by having the drive signal COMC in addition to the drive signals COMA and COMB, it is possible to increase the image formation speed at which a desired image is formed on the medium P without reducing the quality of the image formed on the medium P, and reduce the risk of a decrease in ink ejection accuracy.

[0072] Here, the drive signal VOUT supplied to the piezoelectric element 60 is generated by selecting a signal waveform included in each of the drive signals COMA, COMB, and COMC. That is, when the drive signal selection circuit 200 selects the drive signal COMA, the drive signal COMA is supplied as the drive signal VOUT to the corresponding piezoelectric element 60. When the drive signal selection circuit 200 selects the drive signal COMB, the drive signal COMB is supplied as the drive signal VOUT to the corresponding piezoelectric element 60. When the drive signal selection circuit 200 selects the drive signal COMC, the drive signal COMC is supplied as the drive signal VOUT to the corresponding piezoelectric element 60. That is, the drive circuit 52a outputs the drive signal COMA to be supplied to the piezoelectric element 60, the drive circuit 52b outputs the drive signal COMB to be supplied to the piezoelectric element 60, and the drive circuit 52c outputs the drive signal COMC to be supplied to the piezoelectric element 60.

[0073] 1.3 Configuration of the drive signal output circuit Next, a description will be given of the configuration and operation of the drive circuit 52 that outputs the drive signal COM. Fig. 8 is a diagram showing the configuration of the drive circuit 52. The drive circuit 52 has an integrated circuit 500, an amplifier circuit 550, a demodulation circuit 560, feedback circuits 570 and 572, and other electronic components.

[0074] The integrated circuit 500 has a plurality of terminals including a terminal In, a terminal Bst, a terminal Hdr, a terminal Sw, a terminal Gvd, a terminal Ldr, and a terminal Gnd. The integrated circuit 500 is electrically connected to an external substrate (not shown) via the plurality of terminals. The integrated circuit 500 also includes a digital-to-analog converter (DAC) 511, a modulation circuit 510, a gate drive circuit 520, and a power supply circuit 590.

[0075] The power supply circuit 590 generates voltage signals DAC_HV and DAC_LV and supplies them to the DAC 511. A digital reference drive signal do that defines the signal waveform of the drive signal COM is also input to the DAC 511. The DAC 511 then converts the input reference drive signal do into a reference drive signal ao, which is an analog signal with a voltage value between the voltage signals DAC_HV and DAC_LV, and outputs it to the modulation circuit 510. That is, the maximum value of the voltage amplitude of the reference drive signal ao is defined by the voltage signal DAC_HV, and the minimum value is defined by the voltage signal DAC_LV. The signal obtained by amplifying this analog reference drive signal ao output by the DAC 511 corresponds to the drive signal COM. That is, the reference drive signal ao corresponds to a target signal before amplification of the drive signal COM.

[0076] The modulation circuit 510 generates a modulation signal Ms by modulating the basic drive signal ao, and outputs the modulation signal Ms to the gate drive circuit 520. The modulation circuit 510 includes adders 512 and 513, a comparator 514, an inverter 515, an integral attenuator 516, and an attenuator 517.

[0077] The integral attenuator 516 attenuates and integrates the drive signal COM input via terminal Vfb, and supplies the result to the negative input terminal of the adder 512. The basic drive signal ao is input to the positive input terminal of the adder 512. The adder 512 then subtracts the voltage input to the negative input terminal from the voltage input to the positive input terminal, and supplies the resulting integrated voltage to the positive input terminal of the adder 513.

[0078] The attenuator 517 attenuates the high-frequency components of the drive signal COM input via the terminal Ifb and supplies the resulting voltage to the negative input terminal of the adder 513. The voltage output from the adder 512 is input to the positive input terminal of the adder 513. The adder 513 then generates a voltage signal Os by subtracting the voltage input to the negative input terminal from the voltage input to the positive input terminal, and outputs the resulting voltage signal Os to the comparator 514.

[0079] The comparator 514 outputs a modulated signal Ms that is obtained by pulse-modulating the voltage signal Os input from the adder 513. Specifically, the comparator 514 generates and outputs a modulated signal Ms that goes to H level when the voltage value of the voltage signal Os input from the adder 513 is rising and exceeds a predetermined threshold Vth1, and goes to L level when the voltage value of the voltage signal Os is falling and falls below a predetermined threshold Vth2. Here, the thresholds Vth1 and Vth2 are set to have the relationship threshold Vth1 => threshold Vth2.

[0080] The modulation signal Ms output by the comparator 514 is input to a gate driver 521 included in the gate drive circuit 520, and is also input to a gate driver 522 included in the gate drive circuit 520 via an inverter 515. That is, signals having an exclusive relationship in terms of logical levels are input to the gate drivers 521 and 522. Here, the exclusive relationship in terms of logical levels means that the logical levels of the signals input to the gate drivers 521 and 522 are not simultaneously at the H level. Therefore, the modulation circuit 510 may include a timing control circuit, instead of or in addition to the inverter 515, for controlling the timing of the modulation signal Ms input to the gate driver 521 and the signal whose logical level is an inverted version of the modulation signal Ms input to the gate driver 522.

[0081] The gate drive circuit 520 includes a gate driver 521 and a gate driver 522. The gate driver 521 level-shifts the modulation signal Ms output from the comparator 514 and outputs it from a terminal Hdr as an amplification control signal Hgd.

[0082] Specifically, the gate driver 521 receives a power supply voltage on the high side via a terminal Bst and a power supply voltage on the low side via a terminal Sw. The terminal Bst is connected to one end of a capacitor C5 and the cathode of a diode D1 for preventing backflow. The terminal Sw is connected to the other end of the capacitor C5. The anode of the diode D1 is connected to a terminal Gvd, to which a voltage Vm, e.g., a DC voltage of 7.5 V, is supplied from a power supply circuit (not shown). That is, the voltage Vm is supplied to the anode of the diode D1. Therefore, the potential difference between the terminals Bst and Sw is approximately equal to the voltage Vm. As a result, the gate driver 521 generates an amplification control signal Hgd having a voltage value higher than that of the terminal Sw by the voltage Vm in accordance with the input modulation signal Ms, and outputs the signal from the terminal Hdr.

[0083] The gate driver 522 operates at a lower potential side than the gate driver 521. The gate driver 522 level-shifts a signal obtained by inverting the logical level of the modulation signal Ms output from the comparator 514 by an inverter 515, and outputs the signal as an amplification control signal Lgd from a terminal Ldr.

[0084] Specifically, the gate driver 522 receives a voltage Vm on the high side of its power supply voltage, and a ground potential GND1 via a terminal Gnd on the low side. The gate driver 522 outputs an amplification control signal Lgd from a terminal Ldr, which has a voltage value that is higher than the terminal Gnd by the voltage Vm, in accordance with a signal that is the inverted logical level of the input modulation signal Ms. Here, the ground potential GND1 is the reference potential of the drive circuit 52, and is, for example, 0 V.

[0085] The amplifier circuit 550 includes a transistor M1 and a transistor M2.

[0086] The transistor M1 is a surface-mounted field effect transistor (FET), and a voltage VHV, which is, for example, a DC voltage of 42 V, is supplied to the drain of the transistor M1 as an amplification power supply voltage for the amplifier circuit 550. The gate of the transistor M1 is electrically connected to one end of a resistor R1, and the other end of the resistor R1 is electrically connected to a terminal Hdr of the integrated circuit 500. That is, an amplification control signal Hgd is input to the gate of the transistor M1. The source of the transistor M1 is electrically connected to a terminal Sw of the integrated circuit 500.

[0087] The transistor M2 is a surface-mounted FET, and the drain of the transistor M2 is electrically connected to the terminal Sw of the integrated circuit 500. That is, the drain of the transistor M2 and the source of the transistor M1 are electrically connected to each other. The gate of the transistor M2 is electrically connected to one end of the resistor R2, and the other end of the resistor R2 is electrically connected to the terminal Ldr of the integrated circuit 500. That is, an amplification control signal Lgd is input to the gate of the transistor M2. Furthermore, a ground potential GND1 is supplied to the source of the transistor M2.

[0088] That is, the drive circuit 52 includes surface-mounted transistors M1 and M2 as amplifying transistors. In the amplifier circuit 550, when the drain and source of the transistor M1 are controlled to be non-conductive and the drain and source of the transistor M2 are controlled to be conductive, the potential of the node to which the terminal Sw is connected becomes the ground potential GND1. Therefore, the voltage Vm is supplied to the terminal Bst. On the other hand, when the drain and source of the transistor M1 are controlled to be conductive and the drain and source of the transistor M2 are controlled to be non-conductive, the potential of the node to which the terminal Sw is connected becomes the voltage VHV. Therefore, a voltage signal having a potential of the voltage VHV+Vm is supplied to the terminal Bst. That is, the gate driver 521 that drives the transistor M1 uses the capacitor C5 as a floating power supply, and generates an amplification control signal Hgd whose L level is the potential of the voltage VHV and whose H level is the potential of the voltage VHV + voltage Vm by changing the potential of the terminal Sw to the ground potential GND1 or the voltage VHV depending on the operation of the transistor M1 and the transistor M2, and outputs it to the gate of the transistor M1.

[0089] On the other hand, the gate driver 522 that drives the transistor M2 generates an amplification control signal Lgd whose L level is the ground potential GND1 and whose H level is the potential of the voltage Vm, regardless of the operation of the transistors M1 and M2, and outputs it to the gate of the transistor M2.

[0090] The amplifier circuit 550 configured as described above generates an amplified modulation signal AMs by amplifying the modulation signal Ms based on the voltage VHV at the connection point between the source of the transistor M1 and the drain of the transistor M2. The amplifier circuit 550 then outputs the generated amplified modulation signal AMs to the demodulation circuit 560.

[0091] Here, a capacitor C7 is provided in the propagation path along which the voltage VHV input to the amplifier circuit 550 propagates. Specifically, one end of the capacitor C7 is in the propagation path along which the voltage VHV propagates and is electrically connected to the drain of the transistor M1, and the other end of the capacitor C7 is supplied with the ground potential GND1. This reduces the risk of fluctuations in the potential of the voltage VHV input to the amplifier circuit 550 and reduces the risk of noise being superimposed on the voltage VHV, improving the waveform accuracy of the amplified modulated signal AMs output by the amplifier circuit 550.

[0092] The demodulation circuit 560 demodulates the amplified modulation signal AMs output by the amplifier circuit 550 to generate a drive signal COM, which is output from the drive circuit 52. The demodulation circuit 560 includes an inductor L1 and a capacitor C1. One end of the inductor L1 is connected to one end of the capacitor C1. The amplified modulation signal AMs is input to the other end of the inductor L1. The other end of the capacitor C1 is supplied with a ground potential GND1. That is, in the demodulation circuit 560, the inductor L1 and the capacitor C1 form a low-pass filter. The demodulation circuit 560 demodulates the amplified modulation signal AMs by smoothing it using the low-pass filter, and outputs the demodulated signal as the drive signal COM. That is, the drive circuit 52 outputs the drive signal COM from one end of the inductor L1 and one end of the capacitor C1 included in the demodulation circuit 560.

[0093] The feedback circuit 570 includes resistors R3 and R4. The drive signal COM is supplied to one end of the resistor R3, and the other end is connected to the terminal Vfb and one end of the resistor R4. The voltage VHV is supplied to the other end of the resistor R4. As a result, the drive signal COM that has passed through the feedback circuit 570 is fed back to the terminal Vfb in a state where it has been pulled up by the voltage VHV.

[0094] The feedback circuit 572 includes capacitors C2, C3, and C4 and resistors R5 and R6. The drive signal COM is input to one end of the capacitor C2, and the other end is connected to one end of the resistor R5 and one end of the resistor R6. A ground potential GND1 is supplied to the other end of the resistor R5. This allows the capacitor C2 and the resistor R5 to function as a high-pass filter. The other end of the resistor R6 is connected to one end of the capacitor C4 and one end of the capacitor C3. A ground potential GND1 is supplied to the other end of the capacitor C3. This allows the resistor R6 and the capacitor C3 to function as a low-pass filter. In other words, the feedback circuit 572 includes a high-pass filter and a low-pass filter, and functions as a band-pass filter that passes signals in a predetermined frequency range included in the drive signal COM.

[0095] The other end of the capacitor C4 is connected to the terminal Ifb of the integrated circuit 500. As a result, a signal in which the DC component has been cut out from the high-frequency components of the drive signal COM that has passed through the feedback circuit 572, which functions as a band-pass filter, is fed back to the terminal Ifb.

[0096] The drive signal COM is a signal obtained by smoothing the amplified modulation signal AMs based on the basic drive signal do by the demodulation circuit 560. The drive signal COM is also integrated and subtracted via the terminal Vfb before being fed back to the adder 512. This causes the drive circuit 52 to self-oscillate at a frequency determined by the feedback delay and feedback transfer function. However, the feedback path via the terminal Vfb has a large delay. Therefore, feedback via the terminal Vfb alone may not be able to raise the frequency of self-oscillation sufficiently to ensure the accuracy of the drive signal COM. Therefore, by providing a path that feeds back the high-frequency components of the drive signal COM via the terminal Ifb, in addition to the path via the terminal Vfb, the delay in the entire circuit is reduced. This allows the frequency of the voltage signal Os to be raised sufficiently to ensure the accuracy of the drive signal COM, compared to when the path via the terminal Ifb is not provided.

[0097] As described above, the drive circuit 52 performs digital-to-analog conversion on the input basic drive signal do, then class-D amplifies the analog signal to generate the drive signal COM, and outputs the generated drive signal COM.

[0098] 1.4 Liquid Dispensing Module Configuration Next, the structure of the liquid discharging module 20 will be described with reference to FIGS. 9 to 11. FIG. 9 is a diagram illustrating the structure of the liquid discharging module 20. In describing the structure of the liquid discharging module 20, FIGS. 9 to 11 illustrate arrows indicating the X1, Y1, and Z1 directions, which are perpendicular to one another. In the description of FIGS. 9 to 11, the starting point side of an arrow indicating the X1 direction will be referred to as the -X1 side, and the tip side thereof as the +X1 side. The starting point side of an arrow indicating the Y1 direction will be referred to as the -Y1 side, and the tip side thereof as the +Y1 side. The starting point side of an arrow indicating the Z1 direction will be referred to as the -Z1 side, and the tip side thereof as the +Z1 side. In the following description, the liquid discharging module 20 will be described as having six discharging modules 23, and when distinguishing between the six discharging modules 23, they will be referred to as discharging modules 23-1 to 23-6.

[0099] 9, the liquid ejection module 20 includes a housing 31, an assembly substrate 33, a flow path structure 34, a head substrate 35, distribution channels 37, a fixed plate 39, and ejection modules 23-1 to 23-6. In the liquid ejection module 20, the flow path structure 34, the head substrate 35, the distribution channels 37, and the fixed plate 39 are stacked in this order along the Z1 direction from the −Z1 side to the +Z1 side: the fixed plate 39, the distribution channels 37, the head substrate 35, and the flow path structure 34. The housing 31 is positioned around the flow path structure 34, the head substrate 35, the distribution channels 37, and the fixed plate 39 so as to support the flow path structure 34, the head substrate 35, the distribution channels 37, and the fixed plate 39. The assembly substrate 33 is held by the housing 31 and stands upright on the +Z1 side of the housing 31. The six ejection modules 23 are positioned between the distribution channels 37 and the fixed plate 39 so as to be partially exposed to the outside of the liquid ejection module 20.

[0100] Before describing the structure of the liquid discharging module 20, we will first describe the structure of the discharging module 23 included in the liquid discharging module 20. Fig. 10 is a diagram showing an example of the structure of the discharging module 23. Fig. 11 is a diagram showing an example of a cross section of the discharging module 23. Here, Fig. 11 is a cross section of the discharging module 23 taken along line Aa shown in Fig. 10, and line Aa shown in Fig. 10 is an imaginary line segment that passes through the introduction path 661 included in the discharging module 23 and also passes through the nozzle N1 and nozzle N2.

[0101] 10 and 11, the discharge module 23 has a plurality of nozzles N1 arranged in a row and a plurality of nozzles N2 arranged in a row. The total number of nozzles N1 and nozzles N2 in this discharge module 23 is n, which is the same number as the number of discharge units 600 in the discharge module 23. In the first embodiment, the discharge module 23 will be described assuming that the number of nozzles N1 and the number of nozzles N2 are the same. That is, the discharge module 23 has n / 2 nozzles N1 and n / 2 nozzles N2. Here, in the following description, when there is no need to distinguish between the nozzles N1 and the nozzles N2, they may be simply referred to as nozzles N.

[0102] The ejection module 23 includes a wiring member 388 , a case 660 , a protective substrate 641 , a flow path forming substrate 642 , a communication plate 630 , a compliance substrate 620 , and a nozzle plate 623 .

[0103] In the flow path forming substrate 642, pressure chambers CB1, which are partitioned by a plurality of partition walls by anisotropic etching from one surface side, are arranged in a row corresponding to the nozzles N1, and pressure chambers CB2, which are partitioned by a plurality of partition walls by anisotropic etching from one surface side, are arranged in a row corresponding to the nozzles N2. Here, in the following description, when there is no need to distinguish between the pressure chambers CB1 and CB2, they may be simply referred to as pressure chambers CB.

[0104] The nozzle plate 623 is located on the -Z1 side of the flow path forming substrate 642. The nozzle plate 623 is provided with a nozzle row Ln1 formed by n / 2 nozzles N1 and a nozzle row Ln2 formed by n / 2 nozzles N2. Here, in the following description, the surface of the nozzle plate 623 on the -Z1 side where the nozzles N open may be referred to as the liquid ejection surface 623a.

[0105] A communication plate 630 is located on the -Z1 side of the flow path forming substrate 642 and on the +Z1 side of the nozzle plate 623. The communication plate 630 is provided with a nozzle communication passage RR1 that communicates between the pressure chamber CB1 and the nozzle N1, and a nozzle communication passage RR2 that communicates between the pressure chamber CB2 and the nozzle N2. The communication plate 630 is also provided with a pressure chamber communication passage RK1 that communicates between an end of the pressure chamber CB1 and the manifold MN1, and a pressure chamber communication passage RK2 that communicates between an end of the pressure chamber CB2 and the manifold MN2, which are independent and correspond to the pressure chambers CB1 and CB2, respectively.

[0106] Manifold MN1 includes a supply communication passage RA1 and a connection communication passage RX1. The supply communication passage RA1 penetrates the communication plate 630 along the Z1 direction, while the connection communication passage RX1 does not penetrate the communication plate 630 in the Z1 direction but opens on the nozzle plate 623 side of the communication plate 630 and extends partway in the Z1 direction. Similarly, manifold MN2 includes a supply communication passage RA2 and a connection communication passage RX2. The supply communication passage RA2 penetrates the communication plate 630 along the Z1 direction, while the connection communication passage RX2 does not penetrate the communication plate 630 in the Z1 direction but opens on the nozzle plate 623 side of the communication plate 630 and extends partway in the Z1 direction. The connection communication passage RX1 included in manifold MN1 communicates with the corresponding pressure chamber CB1 via a pressure chamber communication passage RK1, and the connection communication passage RX2 included in manifold MN2 communicates with the corresponding pressure chamber CB2 via a pressure chamber communication passage RK2.

[0107] In the following description, when there is no need to distinguish between the nozzle communication passage RR1 and the nozzle communication passage RR2, they may simply be referred to as the nozzle communication passage RR; when there is no need to distinguish between the manifold MN1 and the manifold MN2, they may simply be referred to as the manifold MN; when there is no need to distinguish between the supply communication passage RA1 and the supply communication passage RA2, they may simply be referred to as the supply communication passage RA; and when there is no need to distinguish between the connection communication passage RX1 and the connection communication passage RX2, they may simply be referred to as the connection communication passage RX.

[0108] A vibration plate 610 is located on the +Z1 side surface of the flow path forming substrate 642. Furthermore, n piezoelectric elements 60 corresponding to the nozzles N1 and N2 are formed in two rows on the +Z1 side surface of the vibration plate 610.

[0109] The piezoelectric element 60 has a piezoelectric body 601 and a pair of electrodes 602, 603 arranged to sandwich the piezoelectric body 601. The electrode 602 and the piezoelectric body 601 are formed for each pressure chamber CB on the +Z1 side surface of the vibration plate 610, and the electrode 603 is configured as a common electrode shared by the pressure chambers CB on the +Z1 side surface of the vibration plate 610. The piezoelectric element 60 is driven so that the piezoelectric body 601 is displaced in the up and down direction by supplying a drive signal VOUT from the drive signal selection circuit 200 to the electrode 602 and a reference voltage signal VBS to the electrode 603, which is the common electrode.

[0110] A protective substrate 641 is bonded to the surface on the +Z1 side of the flow path forming substrate 642. The protective substrate 641 forms a protective space 644 for protecting the piezoelectric element 60. The protective substrate 641 is also provided with a through hole 643 that penetrates along the Z1 direction. Lead electrodes 611 drawn from the electrodes 602, 603 of the piezoelectric element 60 are extended so that their ends are exposed inside the through hole 643. The wiring member 388 is electrically connected to the lead electrodes 611 exposed inside the through hole 643.

[0111] A case 660 is fixed to the protective substrate 641 and the communicating plate 630. The case 660 defines a portion of a manifold MN that communicates with the pressure chambers CB. The case 660 is bonded to the protective substrate 641 and also to the communicating plate 630. Specifically, the case 660 has a recess 665 on its -Z1 side that accommodates the flow path forming substrate 642 and the protective substrate 641. The recess 665 has an opening area larger than the surface where the protective substrate 641 is bonded to the flow path forming substrate 642. The flow path forming substrate 642 and the like are accommodated in the recess 665. The opening surface of the recess 665 on the -Z1 side is sealed by the communicating plate 630 with the flow path forming substrate 642 and the like accommodated in the recess 665. As a result, the case 660, the flow path forming substrate 642, and the protective substrate 641 define supply communication channels RB1 and RB2 on the outer periphery of the flow path forming substrate 642. Here, when there is no need to distinguish between the supply communication passage RB1 and the supply communication passage RB2, they may be simply referred to as the supply communication passage RB.

[0112] Furthermore, a compliance substrate 620 is provided on the surface of the communicating plate 630 where the supply communicating passages RA and the connection communicating passages RX open. The openings of the supply communicating passages RA and the connection communicating passages RX are sealed by this compliance substrate 620. Such a compliance substrate 620 has a sealing film 621 and a fixed substrate 622. The sealing film 621 is formed of a flexible thin film or the like, and the fixed substrate 622 is formed of a hard material, such as a metal, for example, stainless steel.

[0113] An introduction path 661 for supplying ink to the manifold MN is also provided in the case 660. Furthermore, the case 660 is provided with a connection port 662, which is an opening that communicates with the through-hole 643 of the protection substrate 641 and penetrates along the Z1 direction, and through which the wiring member 388 is inserted.

[0114] The wiring member 388 is a flexible member for electrically connecting the discharge module 23 and the head substrate 35, and for example, an FPC can be used. An integrated circuit 201 is mounted on the wiring member 388 by COF (Chip On Film). At least a part of the drive signal selection circuit 200 described above is mounted on this integrated circuit 201.

[0115] In the ejection module 23 configured as described above, the wiring member 388 propagates the drive signals COMA, COMB, COMC, the reference voltage signal VBS, the clock signal SCK, the print data signal SI, and the latch signal LAT. Of these, the drive signals COMA, COMB, COMC, the clock signal SCK, the print data signal SI, and the latch signal LAT are input to a drive signal selection circuit 200 including an integrated circuit 201 provided on the wiring member 388. The drive signal selection circuit 200 generates and outputs a drive signal VOUT by selecting or deselecting the drive signals COMA, COMB, and COMC based on the input clock signal SCK, the print data signal SI, and the latch signal LAT. The drive signal VOUT output by the drive signal selection circuit 200 propagates through the wiring member 388 and is supplied to the electrode 602 via the lead electrode 611. The reference voltage signal VBS propagates through the wiring member 388 and is supplied to the electrode 603 via the lead electrode 611. As a result, the piezoelectric body 601 deforms in accordance with the potential difference between the drive signal VOUT supplied to the electrode 602 and the reference voltage signal VBS supplied to the electrode 603. In other words, the piezoelectric element 60 is driven. As the piezoelectric element 60 is driven, the vibration plate 610 on which the piezoelectric element 60 is provided is displaced in the vertical direction. This causes a change in the internal pressure of the corresponding pressure chamber CB, and ink stored inside the pressure chamber CB is ejected from the nozzle N in accordance with the change in the internal pressure of the pressure chamber CB.

[0116] In the ejection module 23 configured as above, the configuration including the nozzles N, the nozzle communication passages RR, the pressure chambers CB, the piezoelectric elements 60, and the vibration plate 610 corresponds to the above-mentioned ejection sections 600. In other words, the ejection module 23 has a plurality of ejection sections 600 that include the piezoelectric elements 60 and eject ink in response to the driving of the piezoelectric elements 60.

[0117] Returning to FIG. 9, the fixed plate 39 is located on the -Z1 side of the discharge modules 23. Six discharge modules 23 are fixed to the fixed plate 39. Specifically, the fixed plate 39 has six openings 391 that penetrate the fixed plate 39 along the Z2 direction and correspond to the six discharge modules 23, respectively. The six discharge modules 23 are fixed to the fixed plate 39 so that the liquid ejection surfaces 623a are exposed from the six openings 391, respectively.

[0118] The distribution flow path 37 is located on the +Z1 side of the discharge module 23. Four inlet ports 373 are provided on the +Z1 side surface of the distribution flow path 37. The four inlet ports 373 are flow path pipes that protrude from the +Z1 side surface of the distribution flow path 37 to the +Z1 side along the Z1 direction and communicate with flow path holes (not shown) formed on the -Z1 side surface of the flow path structure 34. In addition, flow path pipes (not shown) that communicate with the four inlet ports 373 are located on the -Z1 side surface of the distribution flow path 37. The flow path pipes (not shown) located on the -Z1 side surface of the distribution flow path 37 communicate with the inlet channels 661 of each of the six discharge modules 23. In addition, the distribution flow path 37 has six openings 371 that penetrate along the Z1 direction. Wiring members 388 of each of the six discharge modules 23 are inserted into the six openings 371.

[0119] The head substrate 35 is located on the +Z1 side of the distribution flow path 37. A wiring member FC is attached to the head substrate 35, which is electrically connected to the assembly substrate 33 (described later). Four openings 351 and notches 352 and 353 are formed in the head substrate 35. The wiring members 388 of the discharge modules 23-2 to 23-5 are inserted through the four openings 351 and electrically connected to the head substrate 35 by solder or the like. The wiring member 388 of the discharge module 23-1 passes through the notch 352, and the wiring member 388 of the discharge module 23-6 passes through the notch 353. The wiring members 388 of the discharge modules 23-1 and 23-6 that pass through the notches 352 and 353, respectively, are electrically connected to the head substrate 35 by solder or the like.

[0120] Furthermore, four notches 355 are formed at the four corners of the head substrate 35. Introduction portions 373 pass through the four notches 355. The four introduction portions 373 that pass through the notches 355 are connected to the flow path structure 34 located on the +Z1 side of the head substrate 35.

[0121] The flow path structure 34 includes a flow path plate Su1 and a flow path plate Su2. The flow path plate Su1 and the flow path plate Su2 are stacked along the Z1 direction with the flow path plate Su1 located on the +Z1 side and the flow path plate Su2 located on the -Z1 side, and are bonded to each other with an adhesive or the like. The flow path structure 34 also includes four inlet ports 341 on its +Z1 side surface that protrude toward the +Z1 side along the Z1 direction. The four inlet ports 341 communicate with flow path holes (not shown) formed on the -Z1 side surface of the flow path structure 34 via ink flow paths formed inside the flow path structure 34. The flow path holes (not shown) formed on the -Z1 side surface of the flow path structure 34 communicate with the four inlet ports 373. The flow path structure 34 also includes through holes 343 that penetrate the structure along the Z1 direction. A wiring member FC is inserted through the through holes 343 to electrically connect to the head substrate 35.

[0122] Here, in addition to an ink flow path that connects the introduction section 341 with a flow path hole (not shown) formed on the surface on the -Z1 side, the inside of the flow path structure 34 may also be provided with a capture filter or the like for capturing foreign matter contained in the ink flowing through the ink flow path.

[0123] The housing 31 is positioned so as to cover the periphery of the flow path structure 34, the head substrate 35, the distribution flow paths 37, and the fixed plate 39, and supports the flow path structure 34, the head substrate 35, the distribution flow paths 37, and the fixed plate 39. The housing 31 has four openings 311, an assembly substrate insertion portion 313, and a holding member 315.

[0124] Four introduction parts 341 of the flow path structure 34 are inserted into the four opening parts 311, respectively. Then, ink is supplied from the liquid container 3 to the four introduction parts 341 that have passed through the four opening parts 311 via tubes or the like (not shown).

[0125] The holding member 315 sandwiches the assembly substrate 33 between itself and the housing 31, with a portion of the assembly substrate 33 inserted through the assembly substrate insertion portion 313. The assembly substrate 33 is provided with a connection portion 330. The connection portion 330 is fitted with a connection member 30 that transmits various signals, such as the data signal DATA, drive signals COMA, COMB, and COMC, the reference voltage signal VBS, and other power supply voltages, output by the head drive module 10. The wiring member FC of the head substrate 35 is electrically connected to the assembly substrate 33. This electrically connects the assembly substrate 33 and the head substrate 35. The assembly substrate 33 may also be provided with a semiconductor device equivalent to the restoration circuit 220 described above. While FIG. 9 illustrates a case in which the assembly substrate 33 is provided with one connection portion 330, the assembly substrate 33 may have multiple connection portions 330.

[0126] In the liquid ejection module 20 configured as described above, the liquid container 3 and the introduction portion 341 are connected via a tube (not shown) or the like, so that ink stored in the liquid container 3 is supplied to the liquid ejection module 20. The ink supplied to the liquid ejection module 20 is guided through ink channels formed inside the flow path structure 34 to flow path holes (not shown) formed on the -Z1 side surface of the flow path structure 34, and then supplied to the four introduction portions 373 of the distribution flow paths 37. The ink supplied to the distribution flow paths 37 is distributed to each of the six ejection modules 23 in ink channels (not shown) formed inside the distribution flow path 37, and then supplied to the introduction paths 661 of the corresponding ejection modules 23. The ink supplied to the ejection modules 23 via the introduction paths 661 is then stored in the pressure chambers CB included in the ejection portion 600.

[0127] Furthermore, various signals including the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6, the reference voltage signal VBS, and the data signal DATA output by the head drive module 10 propagate through the connection member 30 and are input to the liquid ejection module 20 via the connection portion 330. The various signals including the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6, the reference voltage signal VBS, and the data signal DATA input to the liquid ejection module 20 propagate through the assembly substrate 33 and the head substrate 35. At this time, the restoration circuit 220 generates clock signals SCK1 to SCK6, print data signals SI1 to SI6, and latch signals LAT1 to LAT6 corresponding to each of the ejection modules 23-1 to 23-6 from the data signal DATA, and separates them corresponding to each of the ejection modules 23-1 to 23-6. The drive signals COMA1-COMA6, COMB1-COMB6, COMC1-COMC6, reference voltage signal VBS, clock signals SCK1-SCK6, print data signals SI1-SI6, and latch signals LAT1-LAT6 are input to the wiring member 388 of the corresponding ejection module 23. The drive signals COMA, COMB, COMC, reference voltage signal VBS, clock signal SCK, print data signal SI, and latch signal LAT supplied to the wiring member 388 propagate through the wiring member 388. At this time, an integrated circuit 201 including a drive signal selection circuit 200 provided on the wiring member 388 generates drive signals VOUT corresponding to each of the n ejection units 600 and supplies them to the electrodes 602 of the piezoelectric elements 60 included in the corresponding ejection units 600. As a result, the n piezoelectric elements 60 are individually driven in response to the drive signals VOUT. As a result, ink stored in the pressure chambers CB corresponding to the piezoelectric elements 60 is ejected from the corresponding nozzles N.

[0128] As described above, in the liquid ejection device 1 of the first embodiment, the liquid ejection module 20 has an electrode 602 and an electrode 603, includes a plurality of piezoelectric elements 60 driven by a drive signal VOUT supplied to the electrode 602 and a reference voltage signal VBS supplied to the electrode 603, and has a plurality of ejection modules 23 that eject ink by driving the piezoelectric elements 60.

[0129] 1.5 Head drive module structure Next, the structure of the head drive module 10 will be described with reference to Figure 12. Here, in describing the structure of the head drive module 10, Figure 12 also shows arrows indicating the X2 direction, Y2 direction, and Z2 direction, which are directions independent of the X1 direction, Y1 direction, and Z1 direction described above and which are perpendicular to one another. In the following description, the starting side of an arrow indicating the X2 direction will be referred to as the -X2 side, and the tip side will be referred to as the +X2 side; the starting side of an arrow indicating the Y2 direction will be referred to as the -Y2 side, and the tip side will be referred to as the +Y2 side; and the starting side of an arrow indicating the Z2 direction will be referred to as the -Z2 side, and the tip side will be referred to as the +Z2 side.

[0130] 12 is a diagram showing an example of the structure of the head drive module 10. As shown in Fig. 12, the head drive module 10 has a drive circuit board 800, a group of heat conduction members 720, a plurality of screws 780, and a cooling fan 770.

[0131] The drive circuit board 800 receives an image information signal IP from the control unit 2 and outputs a plurality of signals including drive signals COMA, COMB, COMC, a reference voltage signal VBS, and a data signal DATA to the liquid ejection module 20. In other words, the drive circuit board 800 drives the piezoelectric element 60 of the liquid ejection module 20.

[0132] The drive circuit board 800 has a plurality of drive circuits 52, a reference voltage output circuit 53, an integrated circuit 101, connection parts CN1 and CN2, and a wiring board 810. The wiring board 810 includes a plurality of through holes 820 that penetrate the wiring board 810 along the Z2 direction. The wiring board 810 also has a plurality of drive circuits 52, a reference voltage output circuit 53, an integrated circuit 101, and connection parts CN1 and CN2 provided thereon.

[0133] The connection part CN1 is located on the +X2 side of the wiring board 810. A cable (not shown) is attached to the connection part CN1 to electrically connect the control unit 2 and the drive circuit board 800. This allows an image information signal IP output by the control unit 2 to be input to the drive circuit board 800. The connection part CN2 is located on the -X2 side of the wiring board 810. A connection member 30 is attached to the connection part CN2 to electrically connect the drive circuit board 800 and the liquid ejection module 20. This allows signals including the drive signals COMA, COMB, COMC, the reference voltage signal VBS, and the data signal DATA output by the drive circuit board 800 to be propagated to the liquid ejection module 20.

[0134] The integrated circuit 101, the reference voltage output circuit 53, and the plurality of drive circuits 52 are located between the connectors CN1 and CN2 on the wiring board 810. Specifically, the integrated circuit 101 is located on the −X2 side of the connector CN1, the reference voltage output circuit 53 is located on the −X2 side of the integrated circuit 101, and the plurality of drive circuits 52 are located side by side along the X2 direction on the −X2 side of the reference voltage output circuit 53. That is, the wiring board 810 is provided with drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 as the plurality of drive circuits 52, and the reference voltage output circuit 53. The configuration provided on the wiring board 810, including the integrated circuit 101, the reference voltage output circuit 53, and the plurality of drive circuits 52, generates signals including drive signals COMA, COMB, and COMC, a reference voltage signal VBS, and a data signal DATA, based on an image information signal IP input from the connector CN1, and outputs the signals to the liquid ejection module 20.

[0135] Here, in addition to the plurality of drive circuits 52, the reference voltage output circuit 53, the integrated circuit 101, and the connection parts CN1 and CN2, a plurality of electronic components may be provided on the wiring board 810. Details of the drive circuit board 800 including the wiring board 810 will be described later.

[0136] The heat sink 710 is located on the +Z2 side of the drive circuit board 800 and is attached to the wiring board 810 with a plurality of screws 780. The heat sink 710 includes a bottom 711, side portions 712 and 713, protrusions 715, 716 and 717, and a plurality of fin portions 718.

[0137] The bottom 711 is positioned opposite the wiring board 810 and has a generally rectangular shape extending in a plane formed by the X2 and Y2 directions. The side 712 protrudes from the -Y2-side end of the bottom 711 toward the -Z2 side and extends along the X2 direction. At least a portion of the -Z2-side end of the side 712 contacts the -Y2-side end of the wiring board 810. The side 713 protrudes from the +Y2-side end of the bottom 711 toward the -Z2 side and extends along the X2 direction. At least a portion of the -Z2-side end of the side 713 contacts the +Y2-side end of the wiring board 810. That is, the bottom 711 and the side portions 712 and 713 of the heat sink 710 form an accommodation space that is open on the -Z2 side. The plurality of drive circuits 52 of the drive circuit board 800 are housed in the housing space formed by the heat sink 710. In other words, the heat sink 710 is attached to the wiring board 810 and is provided so as to cover the plurality of drive circuits 52.

[0138] The protrusions 715, 716, and 717 are provided within the accommodation space defined by the bottom 711 and the side portions 712 and 713, corresponding to the inductor L1, the transistors M1 and M2, and the integrated circuit 500 of each of the multiple drive circuits 52 provided on the wiring substrate 810. Specifically, the protrusion 715 is located corresponding to the inductor L1 provided on the wiring substrate 810, protrudes from the bottom 711 toward the -Z2 side, and extends along the X2 direction. The protrusion 716 is located corresponding to the transistors M1 and M2 provided on the wiring substrate 810, protrudes from the bottom 711 toward the -Z2 side, and extends along the X2 direction. The protrusion 717 is located corresponding to the integrated circuit 500 provided on the wiring substrate 810, protrudes from the bottom 711 toward the -Z2 side, and extends along the X2 direction.

[0139] The multiple fin portions 718 each protrude from the bottom portion 711 toward the -Z2 side, extend along the X2 direction, and are spaced apart from one another in the Y2 direction. Providing multiple fin portions 718 in the heat sink 710 increases the surface area of ​​the heat sink 710, thereby improving the heat dissipation performance of the heat sink 710. The number of such fin portions 718 is set based on an optimal spacing that is determined depending on the amount of heat dissipated by the heat sink 710, the length of the fin portions 718 along the Z2 direction, the airflow acting on the fin portions 718, and the like.

[0140] Heat sink 710 configured as described above is attached to wiring board 810 of drive circuit board 800, thereby dissipating heat generated by multiple drive circuits 52 provided on wiring board 810. Furthermore, heat sink 710 is attached so as to cover multiple drive circuits 52 provided on wiring board 810, thereby functioning as a protective member that protects multiple drive circuits 52 provided on wiring board 810 from impacts and the like. For this reason, heat sink 710 is preferably made of a material that has high thermal conductivity for dissipating heat generated by drive circuits 52, as well as sufficient rigidity for protecting drive circuits 52, and includes a metal such as aluminum, iron, or copper.

[0141] The heat conduction member group 720 is located between the drive circuit board 800 and the heat sink 710. By attaching the heat sink 710 to the wiring board 810, the heat conduction member group 720 comes into contact with both the heat sink 710 and the multiple drive circuits 52 provided on the wiring board 810. As a result, the heat conduction member group 720 improves the contact efficiency between the multiple drive circuits 52 and the heat sink 710, and improves the conduction efficiency of heat conducted from the drive circuit board 800 to the heat sink 710. Such a heat conduction member group 720 is preferably made of a material that has elasticity, flame retardancy, and electrical insulation in addition to thermal conductivity. For example, a gel sheet or rubber sheet containing silicone or acrylic resin and having high thermal conductivity can be used. As a result, the heat conduction member group 720 functions as a conductive member that conducts heat generated in the drive circuit board 800 to the heat sink 710. Furthermore, since the heat conduction member group 720 is made up of a gel sheet or a rubber sheet, the heat conduction member group 720 functions as an insulating member for ensuring electrical insulation performance between the drive circuit board 800 and the heat sink 710, and also functions as a buffer member for alleviating stress that may occur when the heat sink 710 is attached to the drive circuit board 800.

[0142] Specifically, the thermal conduction member group 720 includes thermal conduction members 730, 740, 750, and 760. The thermal conduction member 730 is located between the inductor L1 of each of the multiple drive circuits 52 and the protrusion 715 of the heat sink 710. When the heat sink 710 is attached to the drive circuit board 800, the thermal conduction member 730 comes into contact with both the inductor L1 of each of the multiple drive circuits 52 and the protrusion 715. This increases the efficiency with which the thermal conduction member 730 conducts heat generated in the inductor L1 to the heat sink 710. The thermal conduction member 740 is located between the transistor M1 of each of the multiple drive circuits 52 and the protrusion 716 of the heat sink 710. When the heat sink 710 is attached to the drive circuit board 800, the thermal conduction member 740 comes into contact with both the transistor M1 of each of the multiple drive circuits 52 and the protrusion 716. As a result, the thermal conductive member 740 improves the efficiency of conduction of heat generated in the transistor M1 to the heat sink 710. The thermal conductive member 750 is located between the transistor M2 of each of the multiple drive circuits 52 and the protrusion 716 of the heat sink 710. When the heat sink 710 is attached to the drive circuit board 800, the thermal conductive member 750 comes into contact with both the transistor M2 of each of the multiple drive circuits 52 and the protrusion 716. As a result, the thermal conductive member 750 improves the efficiency of conduction of heat generated in the transistor M2 to the heat sink 710. The thermal conductive member 760 is located between the integrated circuit 500 of each of the multiple drive circuits 52 and the protrusion 717 of the heat sink 710. When the heat sink 710 is attached to the drive circuit board 800, the thermal conductive member 760 comes into contact with both the integrated circuit 500 of each of the multiple drive circuits 52 and the protrusion 717. As a result, the thermal conductive member 760 improves the efficiency of conduction of heat generated in the transistor M2 to the heat sink 710.

[0143] Each of the plurality of screws 780 is inserted from the -Z2 side toward the +Z2 side through each of the plurality of through holes 820 included in the wiring board 810 of the drive circuit board 800. Then, each of the plurality of screws 780 is tightened into the heat sink 710. In this way, the heat sink 710 is attached to the wiring board 810 of the drive circuit board 800.

[0144] The cooling fan 770 is located on the -Z2 side of the heat sink 710. The cooling fan 770 introduces outside air into the head drive module 10 through an opening 714 provided in the upper part of the heat sink 710 on the +X2 side. Specifically, the heat sink 710 has an opening 714 that penetrates between the outside of the heat sink 710 and the storage space defined by the heat sink 710. The cooling fan 770 is attached to the heat sink 710 so as to cover the opening 714. When the cooling fan 770 operates, outside air is introduced into the storage space defined by the heat sink 710 through the opening 714. This improves the circulation efficiency of the air floating inside the storage space defined by the heat sink 710, and further improves the efficiency of dissipating heat generated by the drive circuit 52 housed in the storage space.

[0145] Here, cooling fan 770 only needs to be attached so as to increase the circulation efficiency of air floating inside the storage space formed by heat sink 710. Therefore, opening 714 to which cooling fan 770 is attached only needs to be located on either side of the storage space formed by heat sink 710. Furthermore, the operation of cooling fan 770 to introduce outside air into the storage space formed by heat sink 710 is not limited to the operation of cooling fan 770 to take in outside air into the storage space, but also includes the case where cooling fan 770 operates to exhaust air floating inside the storage space.

[0146] Head drive module 10 configured as described above receives image information signal IP output by control unit 2 via connection CN2. Integrated circuit 101 of head drive module 10 generates and outputs basic drive signals dA1-dA6, dB1-dB6, dC1-dC6 and data signal DATA based on the input image information signal IP, and reference voltage output circuit 53 generates and outputs reference voltage signal VBS. Basic drive signals dA1-dA6, dB1-dB6, dC1-dC6 propagate through wiring board 810 and are input to corresponding drive circuits 52a1-52a6, 52b1-52b6, 52c1-52c6. The drive circuits 52a1-52a6, 52b1-52b6, and 52c1-52c6 generate and output drive signals COMA1-COMA6, COMB1-COMB6, and COMC1-COMC6 in response to the corresponding input base drive signals dA1-dA6, dB1-dB6, and dC1-dC6. The data signal DATA output by the integrated circuit 101, the drive signals COMA1-COMA6, COMB1-COMB6, and COMC1-COMC6 output by the drive circuits 52a1-52a6, 52b1-52b6, and 52c1-52c6, and the reference voltage signal VBS output by the reference voltage output circuit 53 are propagated through the wiring board 810 and output to the liquid ejection module 20 via the connection part CN2.

[0147] 1.6 Configuration of the drive circuit board As described above, in the liquid ejection device 1 of the first embodiment, the piezoelectric elements 60 included in each of the ejection modules 23-1 to 23-6 of the liquid ejection module 20 are driven in accordance with the potential difference between the reference voltage signal VBS and the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 output by the head drive module 10. Each of the ejection modules 23-1 to 23-6 then ejects an amount of ink from the corresponding nozzle N in accordance with the drive amount of the piezoelectric element 60. Therefore, to improve the ejection accuracy of the ink ejected by the liquid ejection module 20, in addition to improving the waveform accuracy of the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 that drive the piezoelectric elements 60, stability in the potential of the reference voltage signal VBS, which serves as the reference potential for driving the piezoelectric elements 60, is required.

[0148] Therefore, from the viewpoint of improving the waveform accuracy of the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 that drive the piezoelectric elements 60 and improving the stability of the potential of the reference voltage signal VBS, an example of the configuration of the drive circuit board 800 that generates the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 and the reference voltage signal VBS and outputs them to the liquid ejection module 20 will be described in more detail.

[0149] FIG. 13 is a diagram showing an example of the electrical connection relationship of the drive circuit board 800. Here, FIG. 13 does not show the integrated circuit 101, which has a small contribution to the waveform accuracy of the drive signals COMA, COMB, and COMC and the reference voltage signal VBS, and the wiring through which the data signal DATA output by the integrated circuit 101 is propagated. On the other hand, the voltage VHV input to each of the drive circuits 52a1-52a6, 52b1-52b6, and 52c1-52c6 contributes greatly to the waveform accuracy of the drive signals COMA1-COMA6, COMB1-COMB6, and COMC1-COMC6 output by each of the drive circuits 52a1-52a6, 52b1-52b6, and 52c1-52c6. Therefore, FIG. 13 shows the voltages VHV input to the multiple drive circuits 52 and the propagation paths through which the voltages VHV propagate. In addition, in Figure 13, the voltage VHV is shown as being supplied from a power supply circuit (not shown) configured outside the drive circuit board 800, but the power supply circuit that generates the voltage VHV may be provided on the drive circuit board 800.

[0150] As described above, drive circuit board 800 has drive circuits 52a1-52a6, 52b1-52b6, 52c1-52c6, reference voltage output circuit 53, and connectors CN1 and CN2, as well as capacitors C6-1-C6-6, C8-1-C8-6, C9a1-C9a6, C9b1-C9b6, and C9c1-C9c6. Drive circuit board 800 also has wiring board 810 which includes wiring WA1-WA6 through which drive signals COMA1-COMA6 are propagated, wiring WB1-WB6 through which drive signals COMB1-COMB6 are propagated, wiring WC1-WC6 through which drive signals COMC1-COMC6 are propagated, wiring WSc, WS1-WS6 through which reference voltage signal VBS is propagated, and wiring WHc, WH1-WH6 through which voltage VHV is propagated.

[0151] The voltage VHV is input to the drive circuit board 800 via the connection part CN1. The voltage VHV then propagates through the wiring WHc provided on the wiring board 810.

[0152] The wiring WH1 is electrically connected to the wiring WHc at the contact Cha1. The wiring WH1 is also electrically connected to the drive circuits 52a1, 52b1, and 52c1. As a result, the voltage VHV propagating through the wiring WHc is input to each of the drive circuits 52a1, 52b1, and 52c1 via the contact Cha1 and the wiring WH1. Each of the drive circuits 52a1, 52b1, and 52c1 amplifies and demodulates the modulation signal Ms based on the input voltage VHV, thereby generating and outputting the drive signals COMA1, COMB1, and COMC1. At this time, the drive signal COMA1 output by the drive circuit 52a1 propagates through the wiring WA1 included in the wiring board 810 and is input to the ejection module 23-1 via the connection part CN2, the drive signal COMB1 output by the drive circuit 52b1 propagates through the wiring WB1 included in the wiring board 810 and is input to the ejection module 23-1 possessed by the liquid ejection module 20 via the connection part CN2, and the drive signal COMC1 output by the drive circuit 52c1 propagates through the wiring WC1 included in the wiring board 810 and is input to the ejection module 23-1 possessed by the liquid ejection module 20 via the connection part CN2.

[0153] Furthermore, a capacitor C6-1 is electrically connected to the wiring WH1. Specifically, one end of the capacitor C6-1 is electrically connected to the wiring WH1 at a contact point Chb1, and the other end is supplied with a ground potential GND2. Here, the ground potential GND2 is a reference potential for the operation of the drive circuit board 800, and may be the same potential as the above-mentioned ground potential GND1. That is, in the drive circuit board 800, the capacitor C6-1 and the above-mentioned capacitor C7 included in each of the drive circuits 52a1, 52b1, and 52c1 are electrically connected in parallel.

[0154] This capacitor C6-1 and each capacitor C7 of drive circuits 52a1, 52b1, and 52c1 reduce voltage fluctuations that may occur in the voltage VHV supplied to each of drive circuits 52a1, 52b1, and 52c1, and reduce the risk of noise being superimposed on the voltage VHV supplied to each of drive circuits 52a1, 52b1, and 52c1. Therefore, it is preferable that each capacitor C6-1 has a large capacitance that can reduce voltage fluctuations and is located near drive circuits 52a1, 52b1, and 52c1 from the perspective of noise reduction.

[0155] In the liquid ejection device 1 of the first embodiment, a capacitor C6-1 and a capacitor C7 provided in each of the drive circuits 52a1, 52b1, and 52c1 are provided in a supply path that supplies the voltage VHV to each of the drive circuits 52a1, 52b1, and 52c1. The capacitor C6-1 reduces the risk of voltage fluctuations occurring in the voltage VHV supplied to each of the drive circuits 52a1, 52b1, and 52c1, and the capacitor C7 provided in each of the drive circuits 52a1, 52b1, and 52c1 reduces the risk of noise being superimposed on the voltage VHV supplied to the corresponding drive circuit 52a1, 52b1, and 52c1. Capacitor C6-1 can be an electrolytic capacitor that can obtain a large capacitance, and capacitor C7 in each of drive circuits 52a1, 52b1, and 52c1 can be a chip ceramic capacitor that is less susceptible to the heat generated in drive circuits 52a1, 52b1, and 52c1 and can be mounted in a space-saving manner, thereby improving the accuracy of voltage VHV supplied to each of drive circuits 52a1, 52b1, and 52c1.

[0156] Similarly, each of the wires WH2 to WH5 is electrically connected to the wire WHc at each of the contact points Cha2 to Cha6. In addition, the wire WH2 is also electrically connected to the drive circuits 52a2, 52b2, and 52c2, the wire WH3 is also electrically connected to the drive circuits 52a3, 52b3, and 52c3, the wire WH4 is also electrically connected to the drive circuits 52a4, 52b4, and 52c4, the wire WH5 is also electrically connected to the drive circuits 52a5, 52b5, and 52c5, and the wire WH6 is also electrically connected to the drive circuits 52a6, 52b6, and 52c6. As a result, the voltage VHV propagating through the wiring WHc is input to each of the drive circuits 52a2, 52b2, and 52c2, each of the drive circuits 52a3, 52b3, and 52c3, each of the drive circuits 52a4, 52b4, and 52c4, each of the drive circuits 52a5, 52b5, and 52c5, and each of the drive circuits 52a6, 52b6, and 52c6.

[0157] The drive circuits 52a2 to 52a6, 52b2 to 52b6, and 52c2 to 52c6 amplify and demodulate the modulated signal Ms based on the input voltage VHV to generate and output the drive signals COMA2 to COMA6, COMB2 to COMB6, and COMC1 to COMC6, respectively. At this time, the drive signals COMA2, COMB2, COMC2 output by the drive circuits 52a2, 52b2, 52c2, respectively, are propagated through the wiring WA2, WB2, WC2 included in the wiring board 810, respectively, and are input to the discharge module 23-2 via the connection part CN2, the drive signals COMA3, COMB3, COMC3 output by the drive circuits 52a3, 52b3, 52c3, respectively, are propagated through the wiring WA3, WB3, WC3 included in the wiring board 810, respectively, and are input to the discharge module 23-3 via the connection part CN2, and the drive signals COMA4, COMB4, COMC4 output by the drive circuits 52a4, 52b4, 52c4, respectively, are propagated through the wiring WA3, WB3, WC3 included in the wiring board 810, respectively, and are input to the discharge module 23-3 via the connection part CN2. The drive signals COMA5, COMB5, COMC5 output by the drive circuits 52a5, 52b5, 52c5 respectively propagate through the wiring WA4, WB4, WC4 included in the board 810 and are input to the discharge module 23-4 via the connection part CN2, and the drive signals COMA5, COMB5, COMC5 output by the drive circuits 52a5, 52b5, 52c5 respectively propagate through the wiring WA5, WB5, WC5 included in the wiring board 810 and are input to the discharge module 23-5 via the connection part CN2, and the drive signals COMA6, COMB6, COMC6 output by the drive circuits 52a6, 52b6, 52c6 respectively propagate through the wiring WA6, WB6, WC6 included in the wiring board 810 and are input to the discharge module 23-6 via the connection part CN2.

[0158] Furthermore, a capacitor C6-2 is electrically connected to the wiring WH2. Specifically, one end of the capacitor C6-2 is electrically connected to the wiring WH2 at a contact point Chb2, and the other end is supplied with a ground potential GND2. That is, on the drive circuit board 800, the capacitor C6-2 and the capacitor C7 included in each of the drive circuits 52a2, 52b2, and 52c2 are electrically connected in parallel. In this case, by using an electrolytic capacitor that can obtain a large capacitance as capacitor C6-2, the risk of voltage fluctuations occurring in the voltage VHV input to each of drive circuits 52a2, 52b2, and 52c2 is reduced, and by arranging capacitor C7 in each of drive circuits 52a2, 52b2, and 52c2 in the vicinity of the corresponding drive circuit 52a2, 52b2, and 52c2, and by using a chip ceramic capacitor that is less susceptible to the heat generated by drive circuits 52a2, 52b2, and 52c2 and can be mounted in a space-saving manner, the accuracy of the voltage VHV supplied to each of drive circuits 52a2, 52b2, and 52c2 is improved.

[0159] Furthermore, a capacitor C6-3 is electrically connected to the wiring WH3. Specifically, one end of the capacitor C6-3 is electrically connected to the wiring WH3 at a contact point Chb3, and the other end is supplied with a ground potential GND2. That is, on the drive circuit board 800, the capacitor C6-3 and the capacitor C7 included in each of the drive circuits 52a3, 52b3, and 52c3 are electrically connected in parallel. In this case, by using an electrolytic capacitor that can obtain a large capacitance as capacitor C6-3, the risk of voltage fluctuations occurring in the voltage VHV input to each of drive circuits 52a3, 52b3, and 52c3 is reduced, and by arranging capacitor C7 in each of drive circuits 52a3, 52b3, and 52c3 near the corresponding drive circuit 52a3, 52b3, and 52c3, and by using a chip ceramic capacitor that is less susceptible to the heat generated by drive circuits 52a3, 52b3, and 52c3 and can be mounted in a space-saving manner, the accuracy of the voltage VHV supplied to each of drive circuits 52a3, 52b3, and 52c3 is improved.

[0160] Furthermore, a capacitor C6-4 is electrically connected to the wiring WH4. Specifically, one end of the capacitor C6-4 is electrically connected to the wiring WH4 at a contact point Chb4, and the other end is supplied with a ground potential GND2. That is, on the drive circuit board 800, the capacitor C6-4 and the capacitor C7 included in each of the drive circuits 52a4, 52b4, and 52c4 are electrically connected in parallel. In this case, by using an electrolytic capacitor that can obtain a large capacitance as capacitor C6-4, the risk of voltage fluctuations occurring in the voltage VHV input to each of drive circuits 52a4, 52b4, and 52c4 is reduced, and by arranging capacitor C7 in each of drive circuits 52a4, 52b4, and 52c4 near the corresponding drive circuit 52a4, 52b4, and 52c4, and by using a chip ceramic capacitor that is less susceptible to the heat generated by drive circuits 52a4, 52b4, and 52c4 and can be mounted in a space-saving manner, the accuracy of the voltage VHV supplied to each of drive circuits 52a4, 52b4, and 52c4 is improved.

[0161] Furthermore, a capacitor C6-5 is electrically connected to the wiring WH5. Specifically, one end of the capacitor C6-5 is electrically connected to the wiring WH5 at a contact point Chb5, and the other end is supplied with a ground potential GND2. That is, on the drive circuit board 800, the capacitor C6-5 and the capacitor C7 included in each of the drive circuits 52a5, 52b5, and 52c5 are electrically connected in parallel. In this case, by using an electrolytic capacitor that can obtain a large capacitance as capacitor C6-5, the risk of voltage fluctuations occurring in the voltage VHV input to each of drive circuits 52a5, 52b5, and 52c5 is reduced, and by arranging capacitor C7 in each of drive circuits 52a5, 52b5, and 52c5 in the vicinity of the corresponding drive circuit 52a5, 52b5, and 52c5, and by using a chip ceramic capacitor that is less susceptible to the heat generated by drive circuits 52a5, 52b5, and 52c5 and can be mounted in a space-saving manner, the accuracy of the voltage VHV supplied to each of drive circuits 52a5, 52b5, and 52c5 is improved.

[0162] Furthermore, a capacitor C6-6 is electrically connected to the wiring WH6. Specifically, one end of the capacitor C6-6 is electrically connected to the wiring WH6 at a contact Chb6, and the other end is supplied with a ground potential GND2. That is, on the drive circuit board 800, the capacitor C6-6 and the capacitor C7 included in each of the drive circuits 52a6, 52b6, and 52c6 are electrically connected in parallel. In this case, by using an electrolytic capacitor that can obtain a large capacitance as capacitor C6-6, the risk of voltage fluctuations occurring in the voltage VHV input to each of drive circuits 52a6, 52b6, and 52c6 is reduced, and by arranging capacitor C7 in each of drive circuits 52a6, 52b6, and 52c6 in the vicinity of the corresponding drive circuit 52a6, 52b6, and 52c6, and by using a chip ceramic capacitor that is less susceptible to the heat generated by drive circuits 52a6, 52b6, and 52c6 and can be mounted in a space-saving manner, the accuracy of the voltage VHV supplied to each of drive circuits 52a6, 52b6, and 52c6 is improved.

[0163] The reference voltage output circuit 53 generates and outputs a reference voltage signal VBS of a predetermined voltage value by stepping down or stepping up the voltage VHV or a voltage signal (not shown). The reference voltage signal VBS output by the reference voltage output circuit 53 propagates through the wiring WSc provided on the wiring substrate 810.

[0164] The wiring WS1 is electrically connected to the wiring WSc at the contact point Csa1. The wiring WH1 is also electrically connected to the discharge module 23-1 via the connection point CN2. This allows the reference voltage signal VBS to be input to the discharge module 23-1. That is, the wiring WH1 is electrically connected to the contact point Csa1 and the electrode 603 of the piezoelectric element 60 of the discharge module 23-1. This allows the reference voltage signal VBS output by the reference voltage output circuit 53 to propagate through the wiring WS1 via the contact point Csa1 and be supplied to the electrodes 603 of the piezoelectric elements 60 of the discharge module 23-1.

[0165] Similarly, each of the wirings WS2 to WS6 is electrically connected to the wiring WSc at each of the contacts Csa2 to Csa6. Furthermore, the wiring WH2 is electrically connected to the discharge module 23-2 via the connection part CN2, the wiring WH3 is electrically connected to the discharge module 23-3 via the connection part CN2, the wiring WH4 is electrically connected to the discharge module 23-4 via the connection part CN2, the wiring WH5 is electrically connected to the discharge module 23-5 via the connection part CN2, and the wiring WH6 is electrically connected to the discharge module 23-6 via the connection part CN2. That is, wiring WH2 is electrically connected between contact Csa2 and electrode 603 of the piezoelectric element 60 of ejection module 23-2, wiring WH3 is electrically connected between contact Csa3 and electrode 603 of the piezoelectric element 60 of ejection module 23-3, wiring WH4 is electrically connected between contact Csa4 and electrode 603 of the piezoelectric element 60 of ejection module 23-4, wiring WH5 is electrically connected between contact Csa5 and electrode 603 of the piezoelectric element 60 of ejection module 23-5, and wiring WH6 is electrically connected between contact Csa6 and electrode 603 of the piezoelectric element 60 of ejection module 23-6.

[0166] As a result, the reference voltage signal VBS output by the reference voltage output circuit 53 propagates through the wiring WS2 via the contact Csa2 and is supplied to the electrodes 603 of the multiple piezoelectric elements 60 possessed by the ejection module 23-2, propagates through the wiring WS3 via the contact Csa3 and is supplied to the electrodes 603 of the multiple piezoelectric elements 60 possessed by the ejection module 23-3, propagates through the wiring WS4 via the contact Csa4 and is supplied to the electrodes 603 of the multiple piezoelectric elements 60 possessed by the ejection module 23-4, propagates through the wiring WS5 via the contact Csa5 and is supplied to the electrodes 603 of the multiple piezoelectric elements 60 possessed by the ejection module 23-5, propagates through the wiring WS6 via the contact Csa6 and is supplied to the electrodes 603 of the multiple piezoelectric elements 60 possessed by the ejection module 23-6.

[0167] That is, the electrodes 603 of the piezoelectric elements 60 in each of the discharge modules 23-1 to 23-6 are electrically connected to one another via the wirings WSc, and WH1 to WH6. The reference voltage signal VBS propagates through the wirings WSc, WH1 to WH6, and is supplied to the electrodes 603 of the piezoelectric elements 60 in each of the discharge modules 23-1 to 23-6. In other words, the reference voltage signal VBS propagates through a propagation path formed by the wirings WH1 to WH6 and the wiring WSc, and this propagation path is electrically connected to the electrodes 603 of the piezoelectric elements 60 in each of the discharge modules 23-1 to 23-6, thereby supplying the reference voltage signal VBS to the electrodes 603 of the piezoelectric elements 60 in each of the discharge modules 23-1 to 23-6.

[0168] The capacitor C8-1 is provided between a propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 in the discharging module 23-1 and ground potential GND2, with one end electrically connected to the propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 at a contact Csb1, and the other end supplied with ground potential GND2. That is, the capacitor C8-1 is electrically connected to the propagation path through which the reference voltage signal VBS propagates at a contact Csb1 provided on the propagation path. In this case, the contact Csb1 to which the capacitor C8-1 is electrically connected is located between the electrode 603 of the piezoelectric element 60 in the discharging module 23-1 and the contact Csa1 in the propagation path through which the reference voltage signal VBS propagates. In other words, the contact point Csb1 is located on the wiring WS1 that electrically connects the contact point Csa1 and the electrode 603 of the piezoelectric element 60 of the ejection module 23-1, within the propagation path along which the reference voltage signal VBS propagates.

[0169] The capacitor C8-2 is provided between a propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 in the discharging module 23-2 and ground potential GND2, with one end electrically connected to the propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 at contact point Csb2, and the other end supplied with ground potential GND2. That is, the capacitor C8-2 is electrically connected to the propagation path through which the reference voltage signal VBS propagates at contact point Csb2 provided on the propagation path. In this case, contact point Csb2 to which the capacitor C8-2 is electrically connected is located between the electrode 603 of the piezoelectric element 60 in the discharging module 23-2 and contact point Csa2 in the propagation path through which the reference voltage signal VBS propagates. In other words, the contact point Csb2 is located on the wiring WS2 that electrically connects the contact point Csa2 and the electrode 603 of the piezoelectric element 60 of the ejection module 23-2, within the propagation path along which the reference voltage signal VBS propagates.

[0170] The capacitor C8-3 is provided between a propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 in the discharging module 23-3 and ground potential GND2, with one end electrically connected to the propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 at a contact Csb3, and the other end supplied with ground potential GND2. That is, the capacitor C8-3 is electrically connected to the propagation path through which the reference voltage signal VBS propagates at a contact Csb3 provided on the propagation path. In this case, the contact Csb3 to which the capacitor C8-3 is electrically connected is located between the electrode 603 of the piezoelectric element 60 in the discharging module 23-3 and the contact Csa3 in the propagation path through which the reference voltage signal VBS propagates. In other words, the contact point Csb3 is located on the wiring WS3 that electrically connects the contact point Csa3 and the electrode 603 of the piezoelectric element 60 of the ejection module 23-3, in the propagation path along which the reference voltage signal VBS propagates.

[0171] The capacitor C8-4 is provided between a propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 in the discharging module 23-4 and ground potential GND2, with one end electrically connected to the propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 at a contact Csb4, and the other end supplied with ground potential GND2. That is, the capacitor C8-4 is electrically connected to the propagation path through which the reference voltage signal VBS propagates at a contact Csb4 provided on the propagation path. In this case, the contact Csb4 to which the capacitor C8-4 is electrically connected is located between the electrode 603 of the piezoelectric element 60 in the discharging module 23-4 and the contact Csa4 in the propagation path through which the reference voltage signal VBS propagates. In other words, the contact point Csb4 is located on the wiring WS4 that electrically connects the contact point Csa4 and the electrode 603 of the piezoelectric element 60 of the ejection module 23-4, within the propagation path along which the reference voltage signal VBS propagates.

[0172] The capacitor C8-5 is provided between a propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 in the discharging module 23-5 and ground potential GND2, with one end electrically connected to the propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 at a contact Csb5, and the other end supplied with ground potential GND2. That is, the capacitor C8-5 is electrically connected to the propagation path through which the reference voltage signal VBS propagates at a contact Csb5 provided on the propagation path. In this case, the contact Csb5 to which the capacitor C8-5 is electrically connected is located between the electrode 603 of the piezoelectric element 60 in the discharging module 23-5 and the contact Csa5 in the propagation path through which the reference voltage signal VBS propagates. In other words, the contact point Csb5 is located on the wiring WS5 that electrically connects the contact point Csa5 and the electrode 603 of the piezoelectric element 60 of the ejection module 23-5, within the propagation path along which the reference voltage signal VBS propagates.

[0173] The capacitor C8-6 is provided between a propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 in the discharging module 23-6 and ground potential GND2, with one end electrically connected to the propagation path that supplies the reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 at a contact Csb6, and the other end supplied with ground potential GND2. That is, the capacitor C8-6 is electrically connected to the propagation path through which the reference voltage signal VBS propagates at a contact Csb6 provided on the propagation path. In this case, the contact Csb6 to which the capacitor C8-6 is electrically connected is located between the electrode 603 of the piezoelectric element 60 in the discharging module 23-6 and the contact Csa6 in the propagation path through which the reference voltage signal VBS propagates. In other words, the contact point Csb6 is located on the wiring WS6 that electrically connects the contact point Csa6 and the electrode 603 of the piezoelectric element 60 of the ejection module 23-6, within the propagation path along which the reference voltage signal VBS propagates.

[0174] One end of the capacitors C9a1, C9b1, and C9c1 is electrically connected to the wiring WS1, and the other end is supplied with a ground potential GND1. The ground potential GND1 is also supplied to each of the drive circuits 52a1, 52b1, and 52c1. The capacitor C9a1 is provided corresponding to the drive circuit 52a1, the capacitor C9b1 is provided corresponding to the drive circuit 52b1, and the capacitor C9c1 is provided corresponding to the drive circuit 52c1. Here, "correspondingly provided" includes that capacitor C9a1 is located near drive circuit 52a1 on wiring board 810 and connected to the same reference potential as drive circuit 52a1, that capacitor C9b1 is located near drive circuit 52b1 on wiring board 810 and connected to the same reference potential as drive circuit 52b1, and that capacitor C9c1 is located near drive circuit 52c1 on wiring board 810 and connected to the same reference potential as drive circuit 52c1.

[0175] One end of the capacitors C9a2, C9b2, and C9c2 is electrically connected to the wiring WS2, and the other end is supplied with a ground potential GND1. The ground potential GND1 is also supplied to each of the drive circuits 52a2, 52b2, and 52c2. The capacitor C9a2 is provided corresponding to the drive circuit 52a2, the capacitor C9b2 is provided corresponding to the drive circuit 52b2, and the capacitor C9c2 is provided corresponding to the drive circuit 52c2. Here, "correspondingly provided" includes that capacitor C9a2 is located near drive circuit 52a2 on wiring board 810 and connected to the same reference potential as drive circuit 52a2, that capacitor C9b2 is located near drive circuit 52b2 on wiring board 810 and connected to the same reference potential as drive circuit 52b2, and that capacitor C9c2 is located near drive circuit 52c2 on wiring board 810 and connected to the same reference potential as drive circuit 52c2.

[0176] One end of the capacitors C9a3, C9b3, and C9c3 is electrically connected to the wiring WS3, and the other end is supplied with a ground potential GND1. The ground potential GND1 is also supplied to each of the drive circuits 52a3, 52b3, and 52c3. The capacitor C9a3 is provided corresponding to the drive circuit 52a3, the capacitor C9b3 is provided corresponding to the drive circuit 52b3, and the capacitor C9c3 is provided corresponding to the drive circuit 52c3. Here, "correspondingly provided" includes capacitor C9a3 being located near drive circuit 52a3 on wiring board 810 and connected to the same reference potential as drive circuit 52a3, capacitor C9b3 being located near drive circuit 52b3 on wiring board 810 and connected to the same reference potential as drive circuit 52b3, and capacitor C9c3 being located near drive circuit 52c3 on wiring board 810 and connected to the same reference potential as drive circuit 52c3.

[0177] One end of the capacitors C9a4, C9b4, and C9c4 is electrically connected to the wiring WS4, and the other end is supplied with a ground potential GND1. The ground potential GND1 is also supplied to each of the drive circuits 52a4, 52b4, and 52c4. The capacitor C9a4 is provided corresponding to the drive circuit 52a4, the capacitor C9b4 is provided corresponding to the drive circuit 52b4, and the capacitor C9c4 is provided corresponding to the drive circuit 52c4. Here, "correspondingly provided" includes that capacitor C9a4 is located near drive circuit 52a4 on wiring board 810 and connected to the same reference potential as drive circuit 52a4, that capacitor C9b4 is located near drive circuit 52b4 on wiring board 810 and connected to the same reference potential as drive circuit 52b4, and that capacitor C9c4 is located near drive circuit 52c4 on wiring board 810 and connected to the same reference potential as drive circuit 52c4.

[0178] One end of the capacitors C9a5, C9b5, and C9c5 is electrically connected to the wiring WS5, and the other end is supplied with a ground potential GND1. The ground potential GND1 is also supplied to each of the drive circuits 52a5, 52b5, and 52c5. The capacitor C9a5 is provided corresponding to the drive circuit 52a5, the capacitor C9b5 is provided corresponding to the drive circuit 52b5, and the capacitor C9c5 is provided corresponding to the drive circuit 52c5. Here, "correspondingly provided" includes capacitor C9a5 being located near drive circuit 52a5 on wiring board 810 and connected to the same reference potential as drive circuit 52a5, capacitor C9b5 being located near drive circuit 52b5 on wiring board 810 and connected to the same reference potential as drive circuit 52b5, and capacitor C9c5 being located near drive circuit 52c5 on wiring board 810 and connected to the same reference potential as drive circuit 52c5.

[0179] One end of capacitors C9a6, C9b6, and C9c6 is electrically connected to wiring WS6, and the other end is supplied with ground potential GND1. Ground potential GND1 is also supplied to drive circuits 52a6, 52b6, and 52c6. Capacitor C9a6 is provided corresponding to drive circuit 52a6, capacitor C9b6 is provided corresponding to drive circuit 52b6, and capacitor C9c6 is provided corresponding to drive circuit 52c6. Here, "correspondingly provided" includes capacitor C9a6 being located near drive circuit 52a6 on wiring board 810 and connected to the same reference potential as drive circuit 52a6, capacitor C9b6 being located near drive circuit 52b6 on wiring board 810 and connected to the same reference potential as drive circuit 52b6, and capacitor C9c6 being located near drive circuit 52c6 on wiring board 810 and connected to the same reference potential as drive circuit 52c6.

[0180] As described above, in the liquid ejection device 1 of the first embodiment, the capacitor C8-1 provided in the propagation path that propagates the reference voltage signal VBS to the ejection module 23-1 reduces the risk of fluctuations in the voltage value of the reference voltage signal VBS supplied to the ejection module 23-1, and also reduces the risk of fluctuations in the voltage value of the reference voltage signal VBS input to the ejection modules 23-2 to 23-6 even if the amount of current generated by the reference voltage signal VBS supplied to the ejection module 23-1 fluctuates as a result of the ink ejection operation by the ejection module 23-1, causing fluctuations in the voltage value of the reference voltage signal VBS supplied to the ejection module 23-1. In other words, by providing the capacitor C8-1 on the wiring WS1 in the propagation path that propagates the reference voltage signal VBS to the ejection module 23-1, the accuracy of the reference voltage signal VBS input to the ejection module 23-1 is improved.

[0181] In addition, the current generated by the drive signals COMA1, COMB1, and COMC1 supplied to the electrode 602 of the piezoelectric element 60 of the ejection module 23-1 is returned to each of the drive circuits 52a1, 52b1, and 52c1 via wiring WS1 electrically connected to the electrode 603 of the electrode 602 of the piezoelectric element 60 of the ejection module 23-1, and a wiring pattern to which a ground potential GND1 is supplied. In the liquid ejection device 1 of the first embodiment, each of the capacitors C9a1, C9b1, and C9c1 is provided corresponding to each of the drive circuits 52a1, 52b1, and 52c1 that supply drive signals COMA1, COMB1, and COMC1 to the ejection module 23-1, and one end is electrically connected to the propagation path that propagates the reference voltage signal VBS to the ejection module 23-1, and the other end is supplied with the same ground potential as each of the drive circuits 52a1, 52b1, and 52c1, thereby shortening the path along which the current generated by the drive signals COMA1, COMB1, and COMC1 supplied to the electrode 602 of the piezoelectric element 60 of the ejection module 23-1 flows. This reduces the inductance component that may be generated due to the current generated by the drive signals COMA1, COMB1, COMC1 supplied to the electrodes 602 of the piezoelectric element 60 of the discharging module 23-1, resulting in an improvement in the waveform accuracy of the drive signals COMA1, COMB1, COMC1 supplied to the electrodes 602 of the piezoelectric element 60 of the discharging module 23-1, and also an improvement in the stability of the voltage value of the reference voltage signal VBS supplied to the electrode 603 of the piezoelectric element 60 of the discharging module 23-1. That is, by providing capacitors C9a1, C9b1, C9c1 corresponding to the drive circuits 52a1, 52b1, 52c1 that supply the drive signals COMA1, COMB1, COMC1 to the discharging module 23-1, respectively, the accuracy of the drive signals COMA1, COMB1, COMC1 and the reference voltage signal VBS input to the discharging module 23-1 is improved.

[0182] Similarly, by providing a capacitor C8-2 on the wiring WS2 of the propagation path that propagates the reference voltage signal VBS to the discharging module 23-2, the accuracy of the reference voltage signal VBS input to the discharging module 23-2 is improved. Also, by providing capacitors C9a2, C9b2, and C9c2 corresponding to the drive circuits 52a2, 52b2, and 52c2 that supply the drive signals COMA2, COMB2, and COMC2 to the discharging module 23-2, respectively, the accuracy of the drive signals COMA2, COMB2, and COMC2 and the reference voltage signal VBS input to the discharging module 23-2 is improved.

[0183] Similarly, by providing a capacitor C8-3 on the wiring WS3 of the propagation path that propagates the reference voltage signal VBS to the discharging module 23-3, the accuracy of the reference voltage signal VBS input to the discharging module 23-3 is improved. Also, by providing capacitors C9a3, C9b3, and C9c3 corresponding to the drive circuits 52a3, 52b3, and 52c3 that supply drive signals COMA3, COMB3, and COMC3 to the discharging module 23-3, respectively, the accuracy of the drive signals COMA3, COMB3, and COMC3 and the reference voltage signal VBS input to the discharging module 23-3 is improved.

[0184] Similarly, by providing a capacitor C8-4 on the wiring WS4 of the propagation path that propagates the reference voltage signal VBS to the discharging module 23-4, the accuracy of the reference voltage signal VBS input to the discharging module 23-4 is improved. Also, by providing capacitors C9a4, C9b4, and C9c4 corresponding to the drive circuits 52a4, 52b4, and 52c4 that supply drive signals COMA4, COMB4, and COMC4 to the discharging module 23-4, respectively, the accuracy of the drive signals COMA4, COMB4, and COMC4 and the reference voltage signal VBS input to the discharging module 23-4 is improved.

[0185] Similarly, by providing a capacitor C8-5 on the wiring WS5 of the propagation path that propagates the reference voltage signal VBS to the discharging module 23-5, the accuracy of the reference voltage signal VBS input to the discharging module 23-5 is improved. Also, by providing capacitors C9a5, C9b5, and C9c5 corresponding to the drive circuits 52a5, 52b5, and 52c5 that supply drive signals COMA5, COMB5, and COMC5 to the discharging module 23-5, respectively, the accuracy of the drive signals COMA5, COMB5, and COMC5 and the reference voltage signal VBS input to the discharging module 23-5 is improved.

[0186] Similarly, by providing a capacitor C8-6 on the wiring WS6 in the propagation path that propagates the reference voltage signal VBS to the discharging module 23-6, the accuracy of the reference voltage signal VBS input to the discharging module 23-6 is improved. Also, by providing capacitors C9a6, C9b6, and C9c6 corresponding to the drive circuits 52a6, 52b6, and 52c6 that supply drive signals COMA6, COMB6, and COMC6 to the discharging module 23-6, respectively, the accuracy of the drive signals COMA6, COMB6, and COMC6 and the reference voltage signal VBS input to the discharging module 23-6 is improved.

[0187] As described above, the drive circuit board 800 includes a drive circuit 52a1 that includes a transistor M1 and capacitors C1 and C7 to one end of which the ground potential GND1 is supplied, and that outputs a drive signal COMA1 to the electrode 602 of the piezoelectric element 60 that drives the piezoelectric element 60 of the discharge module 23-1 so that ink is discharged from the nozzle N of the discharge module 23-1 of the liquid discharge module 20; and a drive circuit 52b1 that includes a transistor M1 and capacitors C1 and C7 to one end of which the ground potential GND1 is supplied, and that outputs a drive signal COMB1 to the electrode 602 of the piezoelectric element 60 that drives the piezoelectric element 60 of the discharge module 23-1 so that ink is discharged from the nozzle N of the discharge module 23-1 of the liquid discharge module 20. The liquid ejection module 20 includes a circuit 52b1, a drive circuit 52c1 including a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and which outputs a drive signal COMC1 to an electrode 602 of the piezoelectric element 60 of the ejection module 23-1 to drive the piezoelectric element 60 of the ejection module 23-1 so that ink is not ejected from the nozzle N of the ejection module 23-1, capacitors C9a1, C9b1, and C9c1, one end of which is electrically connected to an electrode 603 of the piezoelectric element 60 of the ejection module 23-1 and the other end of which is supplied with a ground potential GND1, and a capacitor C8-1, one end of which is electrically connected to the electrode 603 of the piezoelectric element 60 of the ejection module 23-1 and the other end of which is supplied with a ground potential GND2.

[0188] The drive circuit board 800 further includes a drive circuit 52a2 that includes a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and that outputs a drive signal COMA2 to the electrode 602 of the piezoelectric element 60 to drive the piezoelectric element 60 of the discharge module 23-2 so that ink is discharged from the nozzle N of the discharge module 23-2 of the liquid discharge module 20; and a drive circuit 52a2 that includes a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and that outputs a drive signal COMB2 to the electrode 602 of the piezoelectric element 60 to drive the piezoelectric element 60 of the discharge module 23-2 so that ink is discharged from the nozzle N of the discharge module 23-2 of the liquid discharge module 20. 52b2, a drive circuit 52c2 including a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and which outputs a drive signal COMC2 to an electrode 602 of the piezoelectric element 60 of the discharge module 23-2 so that ink is not discharged from the nozzle N of the discharge module 23-2 of the liquid discharge module 20, capacitors C9a2, C9b2, and C9c2, one end of which is electrically connected to the electrode 603 of the piezoelectric element 60 of the discharge module 23-2 and the other end of which is supplied with a ground potential GND1, and a capacitor C8-2, one end of which is electrically connected to the electrode 603 of the piezoelectric element 60 of the discharge module 23-2 and the other end of which is supplied with a ground potential GND2.

[0189] The drive circuit board 800 further includes a drive circuit 52a3 that includes a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and that outputs a drive signal COMA3 to the electrode 602 of the piezoelectric element 60 to drive the piezoelectric element 60 of the discharge module 23-3 so that ink is discharged from the nozzle N of the discharge module 23-3 of the liquid discharge module 20; and a drive circuit 52a3 that includes a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and that outputs a drive signal COMB3 to the electrode 602 of the piezoelectric element 60 to drive the piezoelectric element 60 of the discharge module 23-3 so that ink is discharged from the nozzle N of the discharge module 23-3 of the liquid discharge module 20. 52b3, a drive circuit 52c3 including a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and which outputs a drive signal COMC3 to an electrode 602 of the piezoelectric element 60 of the discharge module 23-3 so that ink is not discharged from the nozzle N of the discharge module 23-3 of the liquid discharge module 20, capacitors C9a3, C9b3, and C9c3, one end of which is electrically connected to the electrode 603 of the piezoelectric element 60 of the discharge module 23-3 and the other end of which is supplied with a ground potential GND1, and a capacitor C8-3, one end of which is electrically connected to the electrode 603 of the piezoelectric element 60 of the discharge module 23-3 and the other end of which is supplied with a ground potential GND2.

[0190] The drive circuit board 800 further includes a drive circuit 52a4 that includes a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and that outputs a drive signal COMA4 to the electrode 602 of the piezoelectric element 60 to drive the piezoelectric element 60 of the discharge module 23-4 so that ink is discharged from the nozzle N of the discharge module 23-4 of the liquid discharge module 20; and a drive circuit 52a4 that includes a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and that outputs a drive signal COMB4 to the electrode 602 of the piezoelectric element 60 to drive the piezoelectric element 60 of the discharge module 23-4 so that ink is discharged from the nozzle N of the discharge module 23-4 of the liquid discharge module 20. 52b4, a drive circuit 52c4 including a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and which outputs a drive signal COMC4 to an electrode 602 of the piezoelectric element 60 of the ejection module 23-4 so that ink is not ejected from the nozzle N of the ejection module 23-4 of the liquid ejection module 20, capacitors C9a4, C9b4, and C9c4, one end of which is electrically connected to the electrode 603 of the piezoelectric element 60 of the ejection module 23-4 and the other end of which is supplied with a ground potential GND1, and a capacitor C8-4, one end of which is electrically connected to the electrode 603 of the piezoelectric element 60 of the ejection module 23-4 and the other end of which is supplied with a ground potential GND2.

[0191] The drive circuit board 800 further includes a drive circuit 52a5 that includes a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and that outputs a drive signal COMA5 to the electrode 602 of the piezoelectric element 60 to drive the piezoelectric element 60 of the discharge module 23-5 so that ink is discharged from the nozzle N of the discharge module 23-5 of the liquid discharge module 20; and a drive circuit 52a5 that includes a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and that outputs a drive signal COMB5 to the electrode 602 of the piezoelectric element 60 to drive the piezoelectric element 60 of the discharge module 23-5 so that ink is discharged from the nozzle N of the discharge module 23-5 of the liquid discharge module 20. 52b5, a drive circuit 52c5 including a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and which outputs a drive signal COMC5 to an electrode 602 of the piezoelectric element 60 of the ejection module 23-5 of the liquid ejection module 20 to drive the piezoelectric element 60 of the ejection module 23-5 so that ink is not ejected from the nozzle N of the ejection module 23-5, capacitors C9a5, C9b5, and C9c5, one end of which is electrically connected to the electrode 603 of the piezoelectric element 60 of the ejection module 23-5 and the other end of which is supplied with a ground potential GND1, and a capacitor C8-5, one end of which is electrically connected to the electrode 603 of the piezoelectric element 60 of the ejection module 23-5 and the other end of which is supplied with a ground potential GND2.

[0192] The drive circuit board 800 further includes a drive circuit 52a6 including a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and which outputs a drive signal COMA6 to an electrode 602 of the piezoelectric element 60, the drive signal COMA6 driving the piezoelectric element 60 of the discharge module 23-6 so that ink is discharged from the nozzle N of the discharge module 23-6 of the liquid discharge module 20; and a drive circuit 52a6 including a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and which outputs a drive signal COMB6 to an electrode 602 of the piezoelectric element 60, the drive signal COMB6 driving the piezoelectric element 60 of the discharge module 23-6 so that ink is discharged from the nozzle N of the discharge module 23-6 of the liquid discharge module 20. 52b6, a drive circuit 52c6 including a transistor M1 and capacitors C1 and C7, one end of which is supplied with a ground potential GND1, and which outputs a drive signal COMC6 to an electrode 602 of the piezoelectric element 60 of the ejection module 23-6 so that ink is not ejected from the nozzle N of the ejection module 23-6 of the liquid ejection module 20, capacitors C9a6, C9b6, and C9c6, one end of which is electrically connected to the electrode 603 of the piezoelectric element 60 of the ejection module 23-6 and the other end of which is supplied with a ground potential GND1, and a capacitor C8-6, one end of which is electrically connected to the electrode 603 of the piezoelectric element 60 of the ejection module 23-6 and the other end of which is supplied with a ground potential GND2.

[0193] Furthermore, the drive circuit board 800 is provided with a reference voltage output circuit 53 that outputs a reference voltage signal VBS to the electrode 603 of the piezoelectric element 60 of the ejection module 23-1, the electrode 603 of the piezoelectric element 60 of the ejection module 23-2, the electrode 603 of the piezoelectric element 60 of the ejection module 23-3, the electrode 603 of the piezoelectric element 60 of the ejection module 23-4, the electrode 603 of the piezoelectric element 60 of the ejection module 23-5, and the electrode 603 of the piezoelectric element 60 of the ejection module 23-6.

[0194] In such a drive circuit board 800, capacitors C9a1 to C9a6, C9b1 to C9b6, and C9c1 to C9c6 are each a chip capacitor, and capacitors C8-1 to C8-6 are each an electrolytic capacitor. That is, the capacitance of each of capacitors C9a1 to C9a6, C9b1 to C9b6, and C9c1 to C9c6 is smaller than the capacitance of each of capacitors C8-1 to C8-6.

[0195] Here, capacitors C9a1 to C9a6, C9b1 to C9b6, and C9c1 to C9c6 all have the same purpose, function, and configuration, and may be simply referred to as capacitor C9 if there is no need to distinguish them in the following description. Furthermore, capacitors C6-1 to C6-6 all have the same purpose, function, and configuration, and may be simply referred to as capacitor C6 if there is no need to distinguish them in the following description. Furthermore, capacitors C8-1 to C8-6 all have the same purpose, function, and configuration, and may be simply referred to as capacitor C8 if there is no need to distinguish them in the following description. Furthermore, in the following description, wiring WSc and WS1 to WS6 through which the reference voltage signal VBS propagates may be collectively referred to as wiring WS.

[0196] Next, a specific example of drive circuit board 800 corresponding to the electrical connection relationship of drive circuit board 800 shown in Fig. 13 will be described. Fig. 14 is a diagram showing an example of the cross-sectional structure of wiring board 810 included in drive circuit board 800. As shown in Fig. 14, wiring board 810 includes surface 831 and surface 832. Surface 831 and surface 832 are positioned opposite each other along the Z2 direction, with surface 831 on the +Z2 side and surface 832 on the -Z2 side.

[0197] Wiring substrate 810 includes multiple layers 840 and layers 841 to 845. Layers 841 to 845 are located between surface 831 and surface 832, and are located in the order of layer 841, layer 842, layer 843, layer 844, and layer 845 in the Z2 direction from the +Z2 side where surface 831 is located to the −Z2 side where surface 832 is located. Multiple layers 840 are located between surface 831 and layer 841, between layer 841 and layer 842, between layer 842 and layer 843, between layer 843 and layer 844, between layer 844 and layer 845, and between layer 845 and surface 832 in the Z2 direction.

[0198] The surfaces 831 and 832 are provided with a plurality of electronic components that configure various circuits, including a plurality of drive circuits 52, and portions of a plurality of wiring patterns that electrically connect the electronic components to one another and propagate various signals. Furthermore, the layers 841 to 845 are provided with portions of a plurality of wiring patterns that electrically connect the electronic components provided on the surfaces 831 and 832 and propagate various signals. The layer 840 provides insulation between the surfaces 831 and 832 and the layers 841 to 845. In other words, the surfaces 831 and 832 and the layers 841 to 845 correspond to wiring layers on which wiring patterns that propagate various signals are provided, and the plurality of layers 840 correspond to insulator layers.

[0199] Each of the surfaces 831 and 832 and layers 841 to 845 corresponding to the wiring layers has a plurality of wiring patterns formed by etching copper foil, which is a material with excellent electrical conductivity for transmitting various signals. The plurality of layers 840 corresponding to the insulator layers are made of a material with excellent insulating properties, and are composed of epoxy glass formed by impregnating glass fiber cloth with epoxy resin.

[0200] As described above, wiring board 810 in the first embodiment includes surface 831 and surface 832 different from surface 831, and is a so-called multilayer board having a plurality of layers between surfaces 831 and 832.

[0201] First, a specific example of the configuration of surfaces 831, 832 on which various electronic components are mounted will be described. Fig. 15 is a diagram showing an example of the configuration of surface 831 of wiring board 810. Here, Fig. 15 shows an example of the configuration of surface 831 when wiring board 810 is viewed from the +Z2 side along the Z2 direction. In the following description, the case where wiring board 810 is viewed from the +Z2 side along the Z2 direction may be referred to as a planar view of wiring board 810.

[0202] 15, wiring board 810 has a generally rectangular shape including sides 811 and 812 facing each other along the X2 direction and sides 813 and 814 facing each other along the Y2 direction. Specifically, side 811 is located on the +X2 side of wiring board 810, side 812 is located on the -X2 side of wiring board 810, side 813 intersects with both sides 811 and 812 and is located on the +Y2 side of wiring board 810, and side 814 intersects with both sides 811 and 812 and is located on the -Y2 side of wiring board 810.

[0203] As shown in FIG. 15, surface 831 of wiring board 810 is provided with connection parts CN1 and CN2, an integrated circuit 101, a plurality of driving circuits 52, a reference voltage output circuit 53, and a plurality of capacitors C9 provided corresponding to each of the plurality of driving circuits 52.

[0204] The connection part CN1 is located along the side 811 and is electrically connected to the control unit 2. Specifically, a cable (not shown) that is electrically connected to the control unit 2 is attached to the connection part CN1. This allows signals including the image information signal IP output by the control unit 2 to be supplied to the head driving module 10. Note that the connection part CN1 may be a BtoB (Board to Board) connector that enables electrical connection between the control unit 2 and the head driving module 10 without a cable.

[0205] The connection part CN2 is located along the side 812 of the wiring board 810, and is electrically connected to the liquid discharging module 20. Specifically, one end of a connection member 30 is attached to the connection part CN2. The other end of the connection member 30 is connected to a connection part 330 of the liquid discharging module 20. As a result, signals including the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 output by the head driving module 10 and the data signal DATA are supplied to the liquid discharging module 20 via the connection part CN2 and the connection member 30. Here, the connection part CN2, 330 may be a BtoB connector, as described above.

[0206] The integrated circuit 101 is located on the -X2 side of the connection part CN1. This integrated circuit 101 includes the entire control circuit 100 and the entire conversion circuit 120 described above. The integrated circuit 101 generates and outputs various signals, including a data signal DATA and basic drive signals dA1 to dA6, dB1 to dB6, and dC1 to dC6, based on an image information signal IP input via the connection part CN1. The data signal DATA output by the integrated circuit 101 propagates through a wiring pattern (not shown) provided on the wiring board 810 and is output to the liquid ejection module 20 via the connection part CN2. Furthermore, the basic drive signals dA1 to dA6, dB1 to dB6, and dC1 to dC6 output by the integrated circuit 101 propagate through a wiring pattern (not shown) provided on the wiring board 810 and are input to the corresponding drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6, respectively. Note that a part of the control circuit 100 or a part of the conversion circuit 120 included in the integrated circuit 101 may be configured outside the integrated circuit 101 .

[0207] The reference voltage output circuit 53 is located on the -X2 side of the integrated circuit 101. The reference voltage output circuit 53 generates and outputs a reference voltage signal VBS by stepping down or stepping up the voltage VHV input from the connection part CN1 or a voltage signal (not shown). The reference voltage signal VBS is then propagated through a wiring pattern provided on the wiring board 810 and supplied to the liquid ejection module 20 via the connection part CN2. Such a reference voltage output circuit 53 may be composed of one or more semiconductor devices, or may be composed of multiple electronic components.

[0208] 15 illustrates an example in which the integrated circuit 101 and the reference voltage output circuit 53 are arranged on a surface 831 of the wiring board 810 together with the plurality of drive circuits 52, but at least one of the integrated circuit 101 and the reference voltage output circuit 53 may be arranged on a surface 832 of the wiring board 810. Furthermore, at least one of the integrated circuit 101 and the reference voltage output circuit 53 may be provided on a circuit board (not shown) different from the wiring board 810.

[0209] The plurality of drive circuits 52 including drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 are positioned between the reference voltage output circuit 53 and the connection part CN2, and are positioned side by side along the X2 direction. Specifically, the driving circuits 52a1 to 52a6, 52b1 to 52b6, 52c1 to 52c6 corresponding to each of the ejection modules 23-1 to 23-6 of the liquid ejection module 20 are arranged on the surface 831 of the wiring board 810 along the X2 direction from the +X2 side to the -X2 side, in the order of driving circuits 52a1, 52b1, 52c1, 52a2, 52b2, 52c2, 52a3, 52b3, 52c3, 52a4, 52b4, 52c4, 52a5, 52b5, 52c5, 52a6, 52b6, 52c6.

[0210] In this case, the transistor M1 and the transistor M2 included in each of the multiple drive circuits 52 are positioned side by side in the X2 direction, with the transistor M1 on the +X2 side and the transistor M2 on the -X2 side, the inductor L1 is positioned on the -Y2 side of the transistors M1 and M2 positioned side by side in the X2 direction, and the integrated circuit 500 is positioned on the +Y2 side of the transistors M1 and M2 positioned side by side in the X2 direction. That is, the integrated circuit 500, the transistors M1 and M2, and the inductor L1 included in the drive circuit 52 are positioned side by side on the surface 831 of the wiring substrate 810, in the direction from the side 813 to the side 814, in the order of the integrated circuit 500, the juxtaposed transistors M1 and M2, and the inductor L1.

[0211] Furthermore, the capacitors C1 and C7 included in each of the multiple drive circuits 52 are located between the transistors M1 and M2 and the inductor L1, which are arranged in parallel along the direction from the side 813 to the side 814. In this case, the capacitor C7 is located near the transistor M1, and the capacitor C1 is located near the inductor L1.

[0212] Capacitor C7 reduces noise that may be superimposed on voltage VHV supplied to the drain of transistor M1 and reduces voltage fluctuations that may occur in voltage VHV. By locating capacitor C7 near transistor M1, the wiring length between capacitor C1 and the drain of transistor M1 can be shortened. As a result, the risk of noise being superimposed on voltage VHV and the risk of fluctuations in the voltage value of voltage VHV input to the drain of transistor M1 are further reduced. This improves the accuracy of voltage VHV supplied to transistor M1 and the accuracy of amplified modulation signal AMs output by amplifier circuit 550 including transistor M1.

[0213] The capacitor C1 and the inductor L1 form a low-pass filter. The amplified modulated signal AMs output by the amplifier circuit 550 is demodulated by the low-pass filter including the capacitor C1 and the inductor L1 to generate the drive signal COM. By positioning the capacitor C1, which constitutes such a low-pass filter, near the inductor L1, the wiring length electrically connecting the capacitor C1 and the inductor L1 can be shortened, thereby improving the operational stability of the low-pass filter constituted by the capacitor C1 and the inductor L1. This improves the waveform accuracy of the drive signal COM output by the demodulation circuit 560, which includes the low-pass filter constituted by the capacitor C1 and the inductor L1.

[0214] Here, on the wiring board 810, the integrated circuits 500 included in each of the multiple drive circuits 52 are positioned side by side along the X2 direction, the juxtaposed transistors M1 and M2 are positioned side by side alternately along the X2 direction, and the inductors L1 are positioned side by side along the X2 direction. That is, on the surface 831 of the wiring board 810, the multiple drive circuits 52 are positioned so as to form a row of the integrated circuits 500 positioned side by side from the side 812 to the side 811, a row of the transistors M1 and M2 positioned side by side from the side 812 to the side 811, and a row of the inductors L1 positioned side by side from the side 812 to the side 811.

[0215] The multiple capacitors C9 are provided corresponding to the multiple drive circuits 52, respectively. Specifically, at least one of the multiple capacitors C9 is located on the -X2 side of the drive circuit 52a1, near the inductor L1 and capacitor C1 of the drive circuit 52a1. The capacitor C9 located near the inductor L1 and capacitor C1 of the drive circuit 52a1 corresponds to the capacitor C9a1 corresponding to the drive circuit 52a1. Furthermore, at least one of the multiple capacitors C9 is located on the -X2 side of the drive circuit 52b1, near the inductor L1 and capacitor C1 of the drive circuit 52b1. The capacitor C9 located near the inductor L1 and capacitor C1 of the drive circuit 52b1 corresponds to the capacitor C9b1 corresponding to the drive circuit 52b1. At least one of the plurality of capacitors C9 is located on the -X2 side of the drive circuit 52c1, near the inductor L1 and capacitor C1 of the drive circuit 52c1. The capacitor C9 located near the inductor L1 and capacitor C1 of the drive circuit 52c1 corresponds to the capacitor C9c1 for the drive circuit 52c1.

[0216] Similarly, multiple capacitors C9 are located near the inductor L1 and capacitor C1 of each of the drive circuits 52a2 to 52a6 on the -X2 side of each of the drive circuits 52a2 to 52a6. The capacitors C9 located near the inductor L1 and capacitor C1 of each of the drive circuits 52a2 to 52a6 correspond to the capacitors C9a2 to C9a6 corresponding to each of the drive circuits 52a2 to 52a6. Furthermore, multiple capacitors C9 are located near the inductor L1 and capacitor C1 of each of the drive circuits 52b2 to 52b6 on the -X2 side of each of the drive circuits 52b2 to 52b6. The capacitors C9 located near the inductor L1 and capacitor C1 of each of the drive circuits 52b2 to 52b6 correspond to the capacitors C9b2 to C9b6 corresponding to each of the drive circuits 52b2 to 52b6. Furthermore, the plurality of capacitors C9 are located on the -X2 side of each of the drive circuits 52c2 to 52c6, near the inductor L1 and capacitor C1 of each of the drive circuits 52c2 to 52c6. The capacitors C9 located near the inductor L1 and capacitor C1 of each of the drive circuits 52c2 to 52c6 correspond to the capacitors C9c2 to C9c1 corresponding to the drive circuits 52c2 to 52c6, respectively.

[0217] As described above, in the liquid ejection device 1 of the first embodiment, the transistor M1 and capacitors C1 and c7 of each of the drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6, and the capacitors C9a1 to C9a6, C9b1 to C9b6, and C9c1 to C9c6 corresponding to each of the drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6, are provided on surface 831 of the wiring substrate 810.

[0218] Fig. 16 is a diagram showing an example of the configuration of surface 832 of wiring substrate 810. Here, Fig. 16 is a perspective view showing an example of the configuration of surface 832 in a plan view of wiring substrate 810. Note that in Fig. 16, some of the components provided other than on surface 832 of wiring substrate 810 are indicated by dashed lines.

[0219] As shown in FIG. 16, a surface 832 of the wiring board 810 is provided with a plurality of capacitors C6 and a plurality of capacitors C8.

[0220] One of the plurality of capacitors C6 is provided on the surface 832 of the wiring board 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a1, 52b1, and 52c1 in a plan view of the wiring board 810. The capacitor C6 provided so as to overlap at least a portion thereof with at least one of the drive circuits 52a1, 52b1, and 52c1 corresponds to the capacitor C6-1 for stabilizing the voltage value of the voltage VHV input to the drive circuits 52a1, 52b1, and 52c1 that output the drive signals COMA1, COMB1, and COMC1 to the discharge module 23-1, respectively. In addition, one of the plurality of capacitors C8 is provided on the surface 832 of the wiring board 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a1, 52b1, and 52c1 in a plan view of the wiring board 810. The capacitor C8, which is provided so as to overlap at least a portion of at least one of the drive circuits 52a1, 52b1, and 52c1, corresponds to the capacitor C8-1 for stabilizing the voltage value of the reference voltage signal VBS supplied to the discharge module 23-1.

[0221] One of the plurality of capacitors C6 is provided on the surface 832 of the wiring board 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a2, 52b2, and 52c2 in a plan view of the wiring board 810. The capacitor C6 provided so as to overlap at least a portion thereof with at least one of the drive circuits 52a2, 52b2, and 52c2 corresponds to the capacitor C6-2 for stabilizing the voltage value of the voltage VHV input to the drive circuits 52a2, 52b2, and 52c2 that output the drive signals COMA2, COMB2, and COMC2 to the discharge module 23-2, respectively. In addition, one of the plurality of capacitors C8 is provided on the surface 832 of the wiring board 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a2, 52b2, and 52c2 in a plan view of the wiring board 810. The capacitor C8, which is provided so as to overlap at least a portion of at least one of the drive circuits 52a2, 52b2, and 52c2, corresponds to the capacitor C8-2 for stabilizing the voltage value of the reference voltage signal VBS supplied to the discharge module 23-2.

[0222] One of the plurality of capacitors C6 is provided on the surface 832 of the wiring board 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a3, 52b3, and 52c3 in a plan view of the wiring board 810. The capacitor C6 provided so as to overlap at least a portion thereof with at least one of the drive circuits 52a3, 52b3, and 52c3 corresponds to the capacitor C6-3 for stabilizing the voltage value of the voltage VHV input to the drive circuits 52a3, 52b3, and 52c3 that output the drive signals COMA3, COMB3, and COMC3 to the discharge module 23-3, respectively. Furthermore, one of the plurality of capacitors C8 is provided on the surface 832 of the wiring board 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a3, 52b3, and 52c3 in a plan view of the wiring board 810. The capacitor C8, which is provided so as to overlap at least a portion of at least one of the drive circuits 52a3, 52b3, and 52c3, corresponds to the capacitor C8-3 for stabilizing the voltage value of the reference voltage signal VBS supplied to the discharge module 23-3.

[0223] One of the plurality of capacitors C6 is provided on the surface 832 of the wiring substrate 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a4, 52b4, and 52c4 in a plan view of the wiring substrate 810. The capacitor C6 provided so as to overlap at least a portion thereof with at least one of the drive circuits 52a4, 52b4, and 52c4 corresponds to the capacitor C6-4 for stabilizing the voltage value of the voltage VHV input to the drive circuits 52a4, 52b4, and 52c4 that output the drive signals COMA4, COMB4, and COMC4 to the discharge module 23-4, respectively. In addition, one of the plurality of capacitors C8 is provided on the surface 832 of the wiring substrate 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a4, 52b4, and 52c4 in a plan view of the wiring substrate 810. The capacitor C8, which is provided so as to overlap at least a portion of at least one of the drive circuits 52a4, 52b4, and 52c4, corresponds to the capacitor C8-4 for stabilizing the voltage value of the reference voltage signal VBS supplied to the discharge module 23-4.

[0224] One of the plurality of capacitors C6 is provided on the surface 832 of the wiring substrate 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a5, 52b5, and 52c5 in a plan view of the wiring substrate 810. The capacitor C6 provided so as to overlap at least a portion thereof with at least one of the drive circuits 52a5, 52b5, and 52c5 corresponds to the capacitor C6-5 for stabilizing the voltage value of the voltage VHV input to the drive circuits 52a5, 52b5, and 52c5 that output the drive signals COMA5, COMB5, and COMC5 to the discharge module 23-5, respectively. Furthermore, one of the plurality of capacitors C8 is provided on the surface 832 of the wiring substrate 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a5, 52b5, and 52c5 in a plan view of the wiring substrate 810. The capacitor C8, which is provided so as to overlap at least a portion of at least one of the drive circuits 52a5, 52b5, and 52c5, corresponds to the capacitor C8-5 for stabilizing the voltage value of the reference voltage signal VBS supplied to the ejection module 23-5.

[0225] One of the plurality of capacitors C6 is provided on a surface 832 of the wiring substrate 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a6, 52b6, and 52c6 in a plan view of the wiring substrate 810. The capacitor C6 provided so as to overlap at least a portion thereof with at least one of the drive circuits 52a6, 52b6, and 52c6 corresponds to a capacitor C6-6 for stabilizing the voltage value of the voltage VHV input to the drive circuits 52a6, 52b6, and 52c6 that output drive signals COMA6, COMB6, and COMC6 to the discharge module 23-6, respectively. Furthermore, one of the plurality of capacitors C8 is provided on a surface 832 of the wiring substrate 810 so as to overlap at least a portion thereof with at least one of the drive circuits 52a6, 52b6, and 52c6 in a plan view of the wiring substrate 810. The capacitor C8, which is provided so as to overlap at least a portion of at least one of the drive circuits 52a6, 52b6, and 52c6, corresponds to the capacitor C8-6 for stabilizing the voltage value of the reference voltage signal VBS supplied to the discharge module 23-6.

[0226] As described above, in the liquid ejection device 1 of the first embodiment, the capacitors C8-1 to C8-6 for stabilizing the voltage value of the reference voltage signal VBS input to each of the ejection modules 23-1 to 23-6 are provided on the surface 832 of the wiring substrate 810. In other words, the capacitors C8-1 to C8-6 are provided on a surface of the wiring substrate 810 different from the surface on which the plurality of drive circuits 52 are provided.

[0227] Here, as described above, capacitors C8-1 to C8-6 preferably have large capacitance, and therefore include electrolytic capacitors. Therefore, the size of capacitors C8-1 to C8-6 is larger than that of multiple capacitors C9 provided on surface 831 of wiring board 810 and including chip capacitors. Specifically, the mounting area of ​​capacitor C9 on wiring board 810 is smaller than the mounting area of ​​capacitor C8 on wiring board 810. In other words, the size of capacitor C9 when viewed normal to wiring board 810 along the Z2 direction is smaller than the size of capacitor C8 when viewed normal to wiring board 810 along the Z2 direction.

[0228] By providing capacitor C9, which can be mounted on wiring board 810 with such a small mounting area, on the same mounting surface of wiring board 810 as multiple drive circuits 52, and providing capacitor C8, which has a large mounting area and can be mounted on wiring board 810, on a different mounting surface of wiring board 810 from multiple drive circuits 52, it is possible to make effective use of the mounting area of ​​wiring board 810 and reduce the risk of drive circuit board 800 becoming larger.

[0229] Next, the configuration of layers 841 to 845 located between surfaces 831 and 832 among the wiring layers of wiring substrate 810 will be described. As shown in FIG. 14, layers 841 to 845 of wiring substrate 810 are located in the order of layer 841, layer 842, layer 843, layer 844, and layer 845 along the Z2 direction, from the +Z2 side where surface 831 is located to the −Z2 side where surface 832 is located. Layer 841 is provided with a wiring pattern that propagates ground potential GND1 of the reference potentials of drive circuit substrate 800. Layer 842 is provided with wiring WA1 to WA6 that propagate drive signals COMA1 to COMA6. Layer 843 is provided with wiring WC1 to WC6 that propagate drive signals COMC1 to COMC6 and wiring WS that propagate reference voltage signal VBS. Furthermore, wirings WB1 to WB6 through which drive signals COMB1 to COMB6 propagate are provided on the layer 844. Furthermore, wiring patterns through which the ground potential GND2 of the reference potential of the drive circuit board 800 propagates are provided on the layer 845.

[0230] That is, wiring board 810 includes: layer 841 including a wiring pattern through which ground potential GND1, which is one of the constant reference potentials of drive circuit board 800, is propagated; layer 842 on which wires WA1 to WA6 through which drive signals COMA1 to COMA6 are propagated, respectively; layer 843 located between layer 842 and layer 844 along the Z2 direction, which is one direction, and on which wires WC1 to WC6 through which drive signals COMC1 to COMC6 are propagated, respectively, and wire WS through which reference voltage signal VBS is propagated; layer 844 on which wires WB1 to WB6 through which drive signals COMB1 to COMB6 are propagated, respectively; and layer 845 including a wiring pattern through which ground potential GND2, which is one of the reference potentials of drive circuit board 800, is propagated.

[0231] That is, in the wiring board 810, a surface 831 on which the plurality of drive circuits 52 and the plurality of capacitors C9 are provided is adjacent to a layer 841 on which a wiring pattern propagating a ground potential GND1 electrically connecting the plurality of drive circuits 52 and the plurality of capacitors C9 is provided, and a surface 832 on which the plurality of capacitors C6 and C8 are provided is adjacent to a layer 845 on which a wiring pattern propagating a ground potential GND2 electrically connecting the plurality of capacitors C6 and C8 is provided. In other words, the shortest distance between the surface 831 and the layer 841 is shorter than the shortest distance between the surface 831 and the layer 845, and the shortest distance between the surface 832 and the layer 845 is shorter than the shortest distance between the surface 832 and the layer 841.

[0232] First, a specific example of the configuration of layer 841 among the inner layers of wiring substrate 810 will be described. Fig. 17 is a diagram showing an example of the configuration of layer 841 of wiring substrate 810. Here, Fig. 17 is a perspective view showing an example of the configuration of layer 841 in a plan view of wiring substrate 810. Note that in Fig. 17, some of the components provided other than layer 841 of wiring substrate 810 are indicated by dashed lines.

[0233] 17, wiring WG1 is formed on substantially the entire surface of layer 841. Specifically, wiring WG1 is formed on layer 841 so that at least a portion of it overlaps with each of drive circuits 52a1-52a6, 52b1-52b6, and 52c1-52c6 in a plan view of wiring board 810. This wiring WG1 is supplied with ground potential GND1, which is one of the reference potentials of drive circuit board 800. That is, the other end of each of capacitors C9a1-C9a6, C9b1-C9b6, and C9c1-C9c6, the other end of capacitor C1 in each of drive circuits 52a1-52a6, 52b1-52b6, and 52c1-52c6, the source of transistor M2, the other end of capacitor C7, and the like are electrically connected to wiring WG1 formed on layer 841.

[0234] Therefore, the other end of capacitor C1, the source of transistor M2, and the other end of capacitor C7 of each of drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6, and the other ends of capacitors C9a1 to C9a6, C9b1 to C9b6, and C9c1 to C9c6 are electrically connected to wiring WG1 through which ground potential GND1 propagates, without passing through a wiring pattern through which ground potential GND2 propagates.

[0235] This shortens the wiring length of the feedback path along which currents generated by the propagation of drive signals COMA1-COMA6, COMB1-COMB6, and COMC1-COMC6 return to each of drive circuits 52a1-52a6, 52b1-52b6, and 52c1-52c6 via capacitors C9a1-C9a6, C9b1-C9b6, and C9c1-C9c6, respectively, and via the wiring pattern through which ground potential GND1 propagates. This improves the waveform accuracy of drive signals COMA1-COMA6, COMB1-COMB6, and COMC1-COMC6, and the stability of the voltage value of reference voltage signal VBS, thereby improving the ejection accuracy of ink ejected from each of ejection modules 23-1-23-6.

[0236] 17 illustrates an example in which only the wiring WG1 is formed on substantially the entire surface of the layer 841, but this is not limiting. That is, in addition to the wiring WG1, the layer 841 may be provided with wiring patterns for transmitting various signals and power supply voltages, such as the data signal DATA, clock signals SCK1 to SCK6 generated by restoring the data signal DATA, print data signals SI1 to SI6, and latch signals LAT1 to LAT6. Furthermore, the layer 841 may be provided with via wiring for electrically connecting the layers of the wiring substrate 810 to each other. Therefore, "the wiring WG1 is formed on substantially the entire surface of the layer 841" does not necessarily mean that the wiring WG1 is formed on the entire area of ​​the layer 841. Specifically, the wiring WG1 may occupy the majority of the area of ​​the layer 841, for example, the wiring WG1 may occupy 50% or more of the entire area of ​​the layer 841.

[0237] Next, a specific example of the configuration of layer 842, one of the inner layers of wiring substrate 810, will be described. Fig. 18 is a diagram showing an example of the configuration of layer 842 of wiring substrate 810. Here, Fig. 18 is a perspective view showing an example of the configuration of layer 842 in a plan view of wiring substrate 810. Note that in Fig. 18, some of the components provided other than layer 842 of wiring substrate 810 are indicated by dashed lines.

[0238] Wiring lines WA1 to WA6 are formed on layer 842. One end of wiring line WA1 is electrically connected to one end of inductor L1 and one end of capacitor C1 in drive circuit 52a1 via vias or the like (not shown), and the other end is electrically connected to connection part CN2 via vias or the like (not shown). As a result, wiring line WA1 propagates drive signal COMA1, which is output by drive circuit 52a1 and supplied to one end, to connection part CN2.

[0239] The wiring WA2 is located on the -X2 side of the wiring WA1 and on the -Y2 side of the wiring WA1. One end of the wiring WA2 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52a2 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WA2 propagates the drive signal COMA2 output by the drive circuit 52a2 and supplied to one end thereof to the connection part CN2.

[0240] The wiring WA3 is located on the -X2 side of the wiring WA2 and on the -Y2 side of the wiring WA2. One end of the wiring WA3 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52a3 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WA3 propagates the drive signal COMA3 output by the drive circuit 52a3 and supplied to one end thereof to the connection part CN2.

[0241] The wiring WA4 is located on the -X2 side of the wiring WA3 and on the -Y2 side of the wiring WA3. One end of the wiring WA4 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52a4 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WA4 propagates the drive signal COMA4 output by the drive circuit 52a4 and supplied to one end thereof to the connection part CN2.

[0242] The wiring WA5 is located on the -X2 side of the wiring WA4 and on the -Y2 side of the wiring WA4. One end of the wiring WA5 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52a5 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WA5 propagates the drive signal COMA5 output by the drive circuit 52a5 and supplied to one end thereof to the connection part CN2.

[0243] The wiring WA6 is located on the -X2 side of the wiring WA5 and on the -Y2 side of the wiring WA5. One end of the wiring WA6 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52a6 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WA6 propagates the drive signal COMA6 output by the drive circuit 52a6 and supplied to one end to the connection part CN2.

[0244] That is, wirings WA1-WA6 that propagate drive signals COMA1-COMA6 output by drive circuits 52a1-52a6, respectively, are formed on layer 842. Here, in addition to wirings WA1-WA6, layer 842 may be provided with wiring patterns that propagate various signals and power supply voltages, such as data signals DATA, clock signals SCK1-SCK6 generated by restoring data signals DATA, print data signals SI1-SI6, and latch signals LAT1-LAT6, and may also be provided with via wiring that interconnects layers of wiring substrate 810.

[0245] As described above, the layer 842 is provided with the wirings WA1 to WA6 through which the drive signals COMA1 to COMA6 output from the drive circuits 52a1 to 52a6 propagate.

[0246] Next, a specific example of the configuration of layer 843 among the inner layers of wiring substrate 810 will be described. Fig. 19 is a diagram showing an example of the configuration of layer 843 of wiring substrate 810. Here, Fig. 19 is a perspective view showing an example of the configuration of layer 843 in a plan view of wiring substrate 810. Note that in Fig. 19, some of the configurations provided other than layer 843 of wiring substrate 810 are indicated by dashed lines.

[0247] Wirings WC1 to WC6 and WS are formed on layer 843. One end of wiring WC1 is electrically connected to one end of inductor L1 and one end of capacitor C1 in drive circuit 52c1 via vias or the like (not shown), and the other end is electrically connected to connection part CN2 via vias or the like (not shown). As a result, wiring WC1 propagates drive signal COMC1, which is output by drive circuit 52c1 and supplied to one end, to connection part CN2.

[0248] The wiring WC2 is located on the -X2 side of the wiring WC1 and on the -Y2 side of the wiring WC1. One end of the wiring WC2 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52c2 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WC2 propagates the drive signal COMC2 output by the drive circuit 52c2 and supplied to one end thereof to the connection part CN2.

[0249] The wiring WC3 is located on the -X2 side of the wiring WC2 and on the -Y2 side of the wiring WC2. One end of the wiring WC3 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52c3 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WC3 propagates the drive signal COMC3 output by the drive circuit 52c3 and supplied to one end thereof to the connection part CN2.

[0250] The wiring WC4 is located on the -X2 side of the wiring WC3 and on the -Y2 side of the wiring WC3. One end of the wiring WC4 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52c4 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WC4 propagates the drive signal COMC4 output by the drive circuit 52c4 and supplied to one end thereof to the connection part CN2.

[0251] The wiring WC5 is located on the -X2 side of the wiring WC4 and on the -Y2 side of the wiring WC4. One end of the wiring WC5 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52c5 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WC5 propagates the drive signal COMC5 output by the drive circuit 52c5 and supplied to one end of the wiring WC5 to the connection part CN2.

[0252] The wiring WC6 is located on the -X2 side of the wiring WC5 and on the -Y2 side of the wiring WC5. One end of the wiring WC6 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52c6 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WC6 propagates the drive signal COMC6 output by the drive circuit 52c6 and supplied to one end thereof to the connection part CN2.

[0253] One end of the wiring WS is electrically connected to the reference voltage output circuit 53 through a via or the like (not shown). That is, the wiring WS propagates the reference voltage signal VBS. Such wiring WS includes wirings WSc and WS1 to WS6 as shown in FIG.

[0254] One end of the wiring WSc is electrically connected to the reference voltage output circuit 53, and extends along the side 814 of the wiring substrate 810. In other words, the region of the wiring WS that extends along the side 814 of the wiring substrate 810 corresponds to the wiring WSc.

[0255] The wiring WS1 is located in a region on the +X2 side and a region on the +Y2 side of the wiring WC1 on the wiring substrate 810. One end of the wiring WS1 is connected to the wiring WSc, and the other end is electrically connected to the connection portion CN2. This allows the wiring WS1 to propagate the reference voltage signal VBS to the connection portion CN2. The connection region where one end of the wiring WC1 and the wiring WSc are electrically connected corresponds to the contact point Csa1 shown in FIG. 13. In this embodiment, the wiring WS1 at least partially overlaps with at least a portion of the drive circuits 52a1, 52b1, and 52c1 in a plan view of the wiring substrate 810, and is electrically connected to one end of the capacitor C8 provided on the surface 832. The region of the wiring WS1 electrically connected to one end of the capacitor C8 corresponds to the contact point Csb1 shown in FIG. 13, and the capacitor C8 corresponds to the capacitor C8-1.

[0256] The wiring WS2 is located between the wiring WC1 and the wiring WC2 on the wiring substrate 810, with one end connected to the wiring WSc and the other end electrically connected to the connection portion CN2. This allows the wiring WS2 to propagate the reference voltage signal VBS to the connection portion CN2. The connection region where one end of the wiring WC2 and the wiring WSc are electrically connected corresponds to the contact point Csa2 shown in FIG. 13. In this embodiment, in a plan view of the wiring substrate 810, at least a portion of the wiring WS2 overlaps with at least a portion of the drive circuits 52a2, 52b2, and 52c2, and is electrically connected to one end of the capacitor C8 provided on the surface 832. The region of the wiring WS2 electrically connected to one end of the capacitor C8 corresponds to the contact point Csb2 shown in FIG. 13, and the capacitor C8 corresponds to the capacitor C8-2.

[0257] The wiring WS3 is located between the wiring WC2 and the wiring WC3 on the wiring substrate 810, with one end connected to the wiring WSc and the other end electrically connected to the connection portion CN2. This allows the wiring WS3 to propagate the reference voltage signal VBS to the connection portion CN2. The connection region where one end of the wiring WC3 and the wiring WSc are electrically connected corresponds to the contact point Csa3 shown in FIG. 13. In this embodiment, the wiring WS3 at least partially overlaps with at least a portion of the drive circuits 52a3, 52b3, and 52c3 in a plan view of the wiring substrate 810, and is electrically connected to one end of the capacitor C8 provided on the surface 832. The region of the wiring WS3 electrically connected to one end of the capacitor C8 corresponds to the contact point Csb3 shown in FIG. 13, and the capacitor C8 corresponds to the capacitor C8-3.

[0258] The wiring WS4 is located between the wiring WC3 and the wiring WC4 on the wiring substrate 810, with one end connected to the wiring WSc and the other end electrically connected to the connection portion CN2. This allows the wiring WS4 to propagate the reference voltage signal VBS to the connection portion CN2. The connection region where one end of the wiring WC4 and the wiring WSc are electrically connected corresponds to the contact point Csa4 shown in FIG. 13. In this embodiment, the wiring WS4 at least partially overlaps with at least a portion of the drive circuits 52a4, 52b4, and 52c4 in a plan view of the wiring substrate 810, and is electrically connected to one end of the capacitor C8 provided on the surface 832. The region of the wiring WS4 electrically connected to one end of the capacitor C8 corresponds to the contact point Csb4 shown in FIG. 13, and the capacitor C8 corresponds to the capacitor C8-4.

[0259] The wiring WS5 is located between the wiring WC4 and the wiring WC5 on the wiring substrate 810, with one end connected to the wiring WSc and the other end electrically connected to the connection portion CN2. This allows the wiring WS5 to propagate the reference voltage signal VBS to the connection portion CN2. The connection region where one end of the wiring WC5 and the wiring WSc are electrically connected corresponds to the contact Csa5 shown in FIG. 13. In this embodiment, the wiring WS5 at least partially overlaps with at least a portion of the drive circuits 52a5, 52b5, and 52c5 in a plan view of the wiring substrate 810, and is electrically connected to one end of the capacitor C8 provided on the surface 832. The region of the wiring WS5 electrically connected to one end of the capacitor C8 corresponds to the contact Csb5 shown in FIG. 13, and the capacitor C8 corresponds to the capacitor C8-5.

[0260] The wiring WS6 is located between the wiring WC5 and the wiring WC6 on the wiring substrate 810, and has one end connected to the wiring WSc and the other end electrically connected to the connection portion CN2. This allows the wiring WS6 to propagate the reference voltage signal VBS to the connection portion CN2. The connection region where one end of the wiring WC6 and the wiring WSc are electrically connected corresponds to the contact point Csa6 shown in FIG. 13. In this embodiment, the wiring WS6 at least partially overlaps with at least a portion of the drive circuits 52a6, 52b6, and 52c6 in a plan view of the wiring substrate 810, and is electrically connected to one end of the capacitor C8 provided on the surface 832. The region of the wiring WS6 electrically connected to one end of the capacitor C8 corresponds to the contact point Csb6 shown in FIG. 13, and the capacitor C8 corresponds to the capacitor C8-6.

[0261] That is, the layer 843 is provided with wiring patterns through which the drive signals COMC1 to COMC6 output by the drive circuits 52c1 to 52c6, respectively, propagate, and a wiring pattern through which the reference voltage signal VBS output by the reference voltage output circuit 53 propagate. In other words, the layer 843 is provided with wiring WS located between the layers 842 and 844 along the Z2 direction, which is one direction, and through which the reference voltage signal VBS propagates. Furthermore, the wiring WC1 to WC6 through which the drive signals COMC1 to COMC6 propagate are provided on the layer 843 on which the wiring WS through which the reference voltage signal VBS propagates are provided, as shown in FIG. 19. That is, the wiring WC1 to WC6 through which the drive signals COMC1 to COMC6 propagate are provided on the layer 843 on which the wiring WS through which the reference voltage signal VBS propagates are provided.

[0262] Here, in addition to the wiring WA1 to WA6 and WS, the layer 843 may be provided with a portion of a wiring pattern through which various signals and power supply voltages are propagated, such as data signals DATA, clock signals SCK1 to SCK6 generated by restoring the data signals DATA, print data signals SI1 to SI6, and latch signals LAT1 to LAT6, and may also be provided with via wiring that interconnects the layers of the wiring board 810.

[0263] Next, a specific example of the configuration of layer 844 among the inner layers of wiring substrate 810 will be described. Fig. 20 is a diagram showing an example of the configuration of layer 844 of wiring substrate 810. Here, Fig. 20 is a perspective view showing an example of the configuration of layer 844 in a plan view of wiring substrate 810. Note that in Fig. 20, some of the configurations provided other than layer 844 of wiring substrate 810 are indicated by dashed lines.

[0264] Wirings WB1 to WB6 are formed on layer 844. One end of the wiring WB1 is electrically connected to one end of an inductor L1 and one end of a capacitor C1 in the drive circuit 52b1 through a via or the like (not shown), and the other end is electrically connected to the connection part CN2 through a via or the like (not shown). As a result, the wiring WB1 propagates the drive signal COMB1 output by the drive circuit 52b1 and supplied to one end thereof to the connection part CN2.

[0265] The wiring WB2 is located on the -X2 side of the wiring WB1 and on the -Y2 side of the wiring WB1. One end of the wiring WB2 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52b2 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WB2 propagates the drive signal COMB2 output by the drive circuit 52b2 and supplied to one end to the connection part CN2.

[0266] The wiring WB3 is located on the -X2 side of the wiring WB2 and on the -Y2 side of the wiring WB2. One end of the wiring WB3 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52b3 via vias or the like (not shown), and the other end is electrically connected to the connection part CN2 via vias or the like (not shown). As a result, the wiring WB3 propagates the drive signal COMB3 output by the drive circuit 52b3 and supplied to one end to the connection part CN2.

[0267] The wiring WB4 is located on the -X2 side of the wiring WB3 and on the -Y2 side of the wiring WB3. One end of the wiring WB4 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52b4 via vias (not shown), and the other end is electrically connected to the connection part CN2 via vias (not shown). As a result, the wiring WB4 propagates the drive signal COMB4 output by the drive circuit 52b4 and supplied to one end to the connection part CN2.

[0268] The wiring WB5 is located on the -X2 side of the wiring WB4 and on the -Y2 side of the wiring WB4. One end of the wiring WB5 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52b5 via vias (not shown), and the other end is electrically connected to the connection part CN2 via vias (not shown). As a result, the wiring WB5 propagates the drive signal COMB5 output by the drive circuit 52b5 and supplied to one end to the connection part CN2.

[0269] The wiring WB6 is located on the -X2 side of the wiring WB5 and on the -Y2 side of the wiring WB5. One end of the wiring WB6 is electrically connected to one end of the inductor L1 and one end of the capacitor C1 of the drive circuit 52b6 via vias (not shown), and the other end is electrically connected to the connection part CN2 via vias (not shown). As a result, the wiring WB6 propagates the drive signal COMB6 output by the drive circuit 52b6 and supplied to one end to the connection part CN2.

[0270] That is, wirings WB1-WB6 that propagate drive signals COMB1-COMB6 output by drive circuits 52b1-52b6, respectively, are formed on layer 844. Here, in addition to wirings WB1-WB6, layer 844 may be provided with wiring patterns that propagate various signals and power supply voltages, such as data signals DATA, clock signals SCK1-SCK6 generated by restoring data signals DATA, print data signals SI1-SI6, and latch signals LAT1-LAT6, and may also be provided with via wiring that interconnects layers of wiring board 810.

[0271] As described above, the layer 844 is provided with the wirings WB1 to WB6 through which the drive signals COMB1 to COMB6 output from the drive circuits 52b1 to 52b6 propagate.

[0272] Next, a specific example of the configuration of layer 845 among the inner layers of wiring substrate 810 will be described. Fig. 21 is a diagram showing an example of the configuration of layer 845 of wiring substrate 810. Here, Fig. 21 is a perspective view showing an example of the configuration of layer 845 in a plan view of wiring substrate 810. Note that in Fig. 21, some of the configurations provided other than layer 845 of wiring substrate 810 are indicated by dashed lines.

[0273] 21, wiring WG2 is formed on substantially the entire surface of layer 845. Specifically, wiring WG2 is formed on layer 845 so that at least a portion of it overlaps with each of drive circuits 52a1-52a6, 52b1-52b6, and 52c1-52c6 in a plan view of wiring board 810. A ground potential GND2 of the reference potential of drive circuit board 800 is supplied to wiring WG2. That is, the other ends of capacitors C6-1-C6-6 and C8-1-C8-6 are electrically connected to wiring WG2 formed on layer 845.

[0274] Therefore, the other ends of capacitors C6-1 to C6-6 and C8-1 to C8-6 are electrically connected to the wiring WG2 through which ground potential GND2 propagates, without passing through wiring WG1 through which ground potential GND1 propagates. Also, as described above, the other end of capacitor C1, the source of transistor M2, and the other end of capacitor C7 in each of drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6, and the other ends of capacitors C9a1 to C9a6, C9b1 to C9b6, and C9c1 to C9c6 are electrically connected to the wiring WG1 through which ground potential GND1 propagates, without passing through a wiring pattern through which ground potential GND2 propagates. Therefore, the distance of the wiring pattern electrically connecting the other end of capacitor C1, the source of transistor M2, and the other end of capacitor C7 in each of drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 to capacitors C9a1 to C9a6, C9b1 to C9b6, and C9c1 to C9c6 is shorter than the distance of the wiring pattern electrically connecting the other end of capacitor C1, the source of transistor M2, and the other end of capacitor C7 in each of drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 to the other ends of capacitors C6-1 to C6-6 and C8-1 to C8-6. In other words, the electrical distance between the other end of capacitor C1, the source of transistor M2, and the other end of capacitor C7 in each of drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 and capacitors C9a1 to C9a6, C9b1 to C9b6, and C9c1 to C9c6 is shorter than the electrical distance between the other end of capacitor C1, the source of transistor M2, and the other end of capacitor C7 in each of drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 and the other ends of capacitors C6-1 to C6-6 and C8-1 to C8-6.

[0275] 21 illustrates an example in which only the wiring WG2 is formed on substantially the entire surface of the layer 845, but this is not limiting. That is, in addition to the wiring WG2, the layer 845 may be provided with wiring patterns for transmitting various signals and power supply voltages, such as the data signal DATA, clock signals SCK1 to SCK6 generated by restoring the data signal DATA, print data signals SI1 to SI6, and latch signals LAT1 to LAT6. Furthermore, the layer 845 may be provided with via wiring for electrically connecting the layers of the wiring substrate 810 to each other. Therefore, "the wiring WG2 is formed on substantially the entire surface of the layer 845" does not necessarily mean that the wiring WG2 is formed on the entire area of ​​the layer 845. Specifically, the wiring WG2 may occupy the majority of the area of ​​the layer 845, for example, the wiring WG1 may occupy 50% or more of the entire area of ​​the layer 845.

[0276] In the drive circuit board 800 configured as described above, at least a portion of the wiring pattern through which the drive signal COMA propagates, at least a portion of the wiring pattern through which the drive signal COMB propagates, and at least a portion of the wiring pattern through which the reference voltage signal VBS propagates are positioned to overlap in a plan view of the wiring board 810. The wiring pattern through which the drive signal COMC propagates, which generates a small amount of current when propagating relative to the drive signals COMA and COMB, is provided in the same wiring layer as at least one of the wiring layer on which the wiring pattern through which the drive signal COMA propagates, the wiring layer on which the wiring pattern through which the drive signal COMB propagates, and the wiring layer on which the wiring pattern through which the reference voltage signal VBS propagates are provided. This reduces the risk of distortion of the signal waveforms of the drive signals COMA, COMB, and COMC due to inductance components of the wiring patterns included in the wiring board 810.

[0277] A specific example of such a configuration will be described with reference to Fig. 22. Fig. 22 is a cross-sectional view of wiring board 810 when wiring board 810 is cut along line Bb shown in Figs.

[0278] 22, the wiring WS1 that propagates the reference voltage signal VBS supplied to the discharge module 23-1 is provided on a layer 843, the wiring WA1 that propagates the drive signal COMA1 is provided on a layer 842, and the wiring WB1 that propagates the drive signal COMB1 is provided on a layer 844. That is, the wiring WA1 and the wiring WS1 are provided on adjacent wiring layers, and the wiring WB1 and the wiring WS1 are provided on adjacent wiring layers. In other words, the layer 842 on which the wiring WA1 is provided and the layer 843 on which the wiring WS1 is provided are located adjacent to each other in the direction along the Z2 direction, which is one direction, and the layer 844 on which the wiring WB1 is provided and the layer 843 on which the wiring WS1 is provided are located adjacent to each other in the direction along the Z2 direction, which is one direction.

[0279] In this case, the wiring WS1 is located between the wiring WA1 and the wiring WB1, and at least a portion of the wiring WA1 and at least a portion of the wiring WB1 are arranged to overlap at least a portion of the wiring WS1 in the Z2 direction. The wiring WC1 that propagates the drive signal COMC1 supplied to the discharge module 23-1 is arranged adjacent to the wiring WS1 on the −Y2 side of the wiring WS1 in the same layer 843 as the wiring WS1.

[0280] The current generated when the drive signals COMA1, COMB1, and COMC1 are input to the discharge module 23-1 propagates through the wiring WA1, WB1, and WC1, and is input to the discharge module 23-1. The current then propagates through the wiring WS1, which also propagates the reference voltage signal VBS, and returns to the drive circuits 52a1, 52b1, and 52c1 that output the drive signals COMA1, COMB1, and COMC1. In other words, currents flow in opposite directions through the wiring WA1, WB1, and WC1 and the wiring WS1. As a result, the inductance components generated by the currents flowing through the wiring WA1, WB1, and WC1 and the inductance component generated by the current flowing through the wiring WS1 cancel each other out. This reduces the risk of waveform distortion due to the inductance components occurring in the signal waveforms of the drive signals COMA1, COMB1, and COMC1.

[0281] Similarly, the wirings WS2 to WS6 that propagate the reference voltage signal VBS supplied to each of the discharge modules 23-2 to 23-6 are provided on a layer 843, the wirings WA2 to WA6 that propagate the drive signals COMA2 to COMA6 are provided on a layer 842, and the wirings WB2 to WB6 that propagate the drive signals COMB2 to COMB6 are provided on a layer 844. That is, the wirings WA2 to WA6 and the wirings WS2 to WS6 are provided on adjacent wiring layers, and the wirings WB2 to WB6 and the wirings WS2 to WS6 are provided on adjacent wiring layers. In other words, layer 842 on which wirings WA2 to WA6 are provided and layer 843 on which wirings WS2 to WS6 are provided are located adjacent to each other in the direction along the Z2 direction, and layer 844 on which wirings WB2 to WB6 are provided and layer 843 on which wirings WS2 to WS6 are provided are located adjacent to each other in the direction along the Z2 direction.

[0282] In this case, the wiring WS2 is located between the wiring WA2 and the wiring WB2, and at least a part of the wiring WA2 and at least a part of the wiring WB2 are arranged to overlap with at least a part of the wiring WS2 in the direction along the Z2 direction; the wiring WS3 is located between the wiring WA3 and the wiring WB3, and at least a part of the wiring WA3 and at least a part of the wiring WB3 are arranged to overlap with at least a part of the wiring WS3 in the direction along the Z2 direction; the wiring WS4 is located between the wiring WA4 and the wiring WB4, and at least a part of the wiring WA4 and the wiring WB At least a portion of wiring WS4 is arranged to overlap at least a portion of wiring WS4 in the direction along the Z2 direction, wiring WS5 is located between wiring WA5 and wiring WB5, and at least a portion of wiring WA5 and at least a portion of wiring WB5 are arranged to overlap at least a portion of wiring WS5 in the direction along the Z2 direction, and wiring WS6 is located between wiring WA6 and wiring WB6, and at least a portion of wiring WA6 and at least a portion of wiring WB6 are arranged to overlap at least a portion of wiring WS6 in the direction along the Z2 direction.

[0283] The wiring WC2 that propagates the drive signal COMC2 supplied to the discharge module 23-2 is provided adjacent to the wiring WS2 on the −Y2 side of the wiring WS2 in the same layer 843 as the wiring WS2, the wiring WC3 that propagates the drive signal COMC3 supplied to the discharge module 23-3 is provided adjacent to the wiring WS3 on the −Y2 side of the wiring WS3 in the same layer 843 as the wiring WS3, and the wiring WC4 that propagates the drive signal COMC4 supplied to the discharge module 23-4 is provided adjacent to the wiring WS3 on the −Y2 side of the wiring WS3 in the same layer 843 as the wiring WS3. Wiring WC5, which propagates drive signal COMC5 supplied to ejection module 23-5, is arranged adjacent to wiring WS4 on the -Y2 side of wiring WS4 in the same layer 843 as wiring S4, and is arranged adjacent to wiring WS5 on the -Y2 side of wiring WS5 in the same layer 843 as wiring WS5, and wiring WC6, which propagates drive signal COMC6 supplied to ejection module 23-6, is arranged adjacent to wiring WS6 on the -Y2 side of wiring WS6 in the same layer 843 as wiring WS6.

[0284] This causes the inductance components generated by the current flowing through each of the wirings WA2 to WA6, WB2 to WB6, and WC2 to WC6 to cancel out the inductance components generated by the current flowing through the wirings WS2 to WS6, thereby reducing the risk of waveform distortion caused by the inductance components occurring in the signal waveforms of the drive signals COMA2 to SOMA6, COMB2 to COMB6, and COMC2 to COMC6.

[0285] Furthermore, as described above, wiring substrate 810 includes layer 841 on which wiring WG1, which propagates a constant potential GGND1, is provided, and layer 845 on which wiring WG2, which propagates a constant ground potential GND2, is provided. Layer 841 on which wiring WG1 is provided is located on the +Z2 side of layer 842 on which wiring WA1 to WA6 are provided, and layer 845 on which wiring WG2 is provided is located on the −Z2 side of layer 844 on which wiring WB1 to WB6 are provided. In other words, layer 842 is located between layer 843 and layer 841, and layer 844 is located between layer 843 and layer 845. In this case, at least a portion of wiring WG1 is arranged to overlap at least a portion of each of wirings WA1 to WA6 in the Z2 direction, and at least a portion of wiring WG2 is arranged to overlap at least a portion of wirings WB1 to WB6 in the Z2 direction.

[0286] As a result, the wiring WG1 functions as a shielding member that reduces the risk of disturbance noise and the like being superimposed on each of the wirings WA1 to WA6, and the wiring WG2 functions as a shielding member that reduces the risk of disturbance noise and the like being superimposed on each of the wirings WB1 to WB6. As a result, the accuracy of the signal waveforms of the drive signals COMA1 to COMA6 propagating through the wirings WA1 to WA6 and the drive signals COMB1 to COMB6 propagating through the wirings WB1 to WB6 is further improved.

[0287] In the liquid ejection device 1 configured as described above, the liquid ejection module 20 is an example of a liquid ejection head, the electrode 602 of the piezoelectric element 60 of the liquid ejection module 20 is an example of a first electrode, and the electrode 603 is an example of a second electrode. Furthermore, any one of drive circuits 52a1 to 52a1 is an example of a first drive circuit, any one of drive circuits 52b1 to 52b1 is an example of a second drive circuit, capacitors C9a1 to C9a1 corresponding to drive circuits 52a1 to 52a1 corresponding to the first drive circuit are an example of a first capacitor, capacitors C8-1 to C8-6 corresponding to drive circuits 52a1 to 52a1 corresponding to the first drive circuit are an example of a second capacitor, capacitors C9b1 to C9b6 corresponding to drive circuits 52b1 to 52b1 corresponding to the second drive circuit are an example of a third capacitor, drive signals COMA1 to COMA6 output by drive circuits 52a1 to 52a1 corresponding to the first drive circuit are an example of a first drive signal, drive signals COMB1 to COMB6 output by drive circuits 52b1 to 52b1 corresponding to the second drive circuit are an example of a second drive signal, and reference voltage signal VBS is an example of a reference voltage signal. Furthermore, wiring board 810 is an example of a substrate, surface 831 is an example of a first surface, surface 832 is an example of a second surface, layer 841 is an example of a first wiring layer, layer 845 is an example of a second wiring layer, layer 843 is an example of a third wiring layer, wiring WG1 provided on layer 841 and propagating ground potential GND1 is an example of a first ground wiring, wiring WG2 provided on layer 845 and propagating ground potential GND2 is an example of a second ground wiring, and wiring WS provided on layer 843 and propagating reference voltage signal VBS is an example of a reference voltage signal wiring.

[0288] Of the transistors M1 and M2 included in the amplifier circuit 550 of the drive circuit 52a1 to 52a1 corresponding to the first drive circuit, the transistor M2 having a source terminal supplied with a ground potential GND1 is an example of an amplifying transistor, the voltage VHV supplied to the amplifier circuit 550 of the drive circuit 52a1 to 52a1 corresponding to the first drive circuit is an example of an amplifying power supply voltage, the capacitor C7 included in the amplifier circuit 550 of the drive circuit 52a1 to 52a1 corresponding to the first drive circuit and having one end supplied with a voltage VHV and one end supplied with a ground potential GND1 is an example of a stabilizing capacitor, and the capacitor C1 included in the demodulation circuit 560 of the drive circuit 52a1 to 52a1 corresponding to the first drive circuit and constituting a low-pass filter is an example of a low-pass filter capacitor. At least one of the transistor M2 and the capacitors C1 and C7 of the drive circuits 52a1 to 52a1 corresponding to the first drive circuit is an example of a first circuit element, and at least one of the transistor M2 and the capacitors C1 and C7 of the drive circuits 52b1 to 52b1 corresponding to the second drive circuit is an example of a second circuit element.

[0289] 1.7 Effects In the liquid ejection device 1 configured as described above, the piezoelectric element is driven by a drive signal COMA1 supplied to the electrode 602 and a reference voltage signal VBS supplied to the electrode 603, thereby driving the liquid ejection module 20 that ejects ink. In the drive circuit board 800, a transistor M1 supplied with a ground potential GND1, which is included in the drive circuit 52a1 that outputs the drive signal COMA1 to the electrode 602 of the piezoelectric element 60, capacitors C1 and C7, and capacitor C9a1, which is a chip capacitor having one end electrically connected to the electrode 603 of the piezoelectric element and the other end supplied with a ground potential GND1, are provided on a surface 831 of the wiring board 810, and capacitor C8-1, which is an electrolytic capacitor having one end electrically connected to the electrode 603 of the piezoelectric element and the other end supplied with a ground potential GND2, is provided on a surface 832 of the wiring board 810 that is different from the surface 831.

[0290] The current generated by the propagation of the drive signal COMA1 returns to the drive circuit 52a1 via each of the capacitors C9a1 and the ground potential GND1. In the drive circuit board 800 of the liquid ejection device 1 of the first embodiment, the transistor M1, capacitors C1 and C7 included in the drive circuit 52a1, and the chip capacitor C9a1 are all provided on the surface 831 of the wiring board 810, which shortens the electrical distance between the transistor M1, capacitors C1 and C7 included in the drive circuit 52a1 and the chip capacitor C9a1 in the wiring pattern through which the ground potential GND1 propagates. In other words, the wiring length of the feedback path through which the current generated by the propagation of the drive signal COMA1 returns to the drive circuit 52a1 can be shortened. This improves the waveform accuracy of the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 and the stability of the voltage value of the reference voltage signal VBS, thereby improving the ejection accuracy of the ink ejected from each of the ejection modules 23-1 to 23-6.

[0291] In this case, wiring board 810 includes layer 841 including wiring WG1 provided with ground potential GND1 to which transistor M1, capacitors C1 and C7 included in drive circuit 52a1 and capacitor C9a1, which is a chip capacitor, are electrically connected, and layer 845 including wiring WG2 provided with ground potential GND2 to which capacitor C8-1 is electrically connected. In wiring board 810, surfaces 831, 832 and layers 841, 845 are positioned so that the shortest distance between surface 831 and layer 841 is shorter than the shortest distance between surface 831 and layer 845, and the shortest distance between surface 832 and layer 845 is shorter than the shortest distance between surface 832 and layer 841, thereby further shortening the wiring length of the feedback path along which the current generated by the propagation of drive signal COMA1 returns to drive circuit 52a1.

[0292] Furthermore, in the liquid ejection device 1 of the first embodiment, the drive circuit board 800 supplies a reference voltage signal VBS to the electrodes 603 of the piezoelectric elements 60 included in each of the ejection modules 23-1 to 23-6 via the wiring WS. Specifically, in the ejection module 23-1, the reference voltage signal VBS supplied to the wiring WSc of the wiring WS branches at the contact point Csa1, propagates through the wiring WS1, and is supplied to the electrodes 603 of the piezoelectric elements 60 included in the ejection module 23-1. In each of the ejection modules 23-2 to 23-6, the reference voltage signal VBS supplied to the wiring WSc of the wiring WS branches at the contact points Csa2 to Csa6, propagates through the wirings WS2 to WS6, and is supplied to the electrodes 603 of the piezoelectric elements 60 included in the ejection modules 23-2 to 23-6.

[0293] In this case, the wiring WS1 that electrically connects the contact Csa1 and the electrode 603 of the piezoelectric element 60 of the discharge module 23-1 has a contact Csb1 to which the capacitor C8-1 is electrically connected. As a result, even if fluctuations occur in the voltage value of the reference voltage signal VBS due to the operation of any of the discharge modules 23-2 to 23-6, the fluctuations in the voltage value are absorbed by the capacitor C8-1. As a result, the risk of fluctuations in the voltage value of the reference voltage signal VBS supplied to the discharge module 23-1 is reduced.

[0294] Furthermore, in the liquid ejection device 1 of the first embodiment, a contact Csb2 to which a capacitor C8-2 is electrically connected is located on a wiring WS2 that electrically connects the contact Csa2 and the electrode 603 of the piezoelectric element 60 that the ejection module 23-2 has, a contact Csb3 to which a capacitor C8-3 is electrically connected is located on a wiring WS3 that electrically connects the contact Csa3 and the electrode 603 of the piezoelectric element 60 that the ejection module 23-3 has, and a contact Csb4 to which a capacitor C8-4 is electrically connected is located on a wiring WS3 that electrically connects the contact Csa4 and the electrode 603 of the piezoelectric element 60 that the ejection module 23-4 has. 03, a contact Csb4 to which a capacitor C8-4 is electrically connected is located, a contact Csb5 to which a capacitor C8-5 is electrically connected is located on a wiring WS5 that electrically connects the contact Csa5 and the electrode 603 of the piezoelectric element 60 of the ejection module 23-5, and a contact Csb6 to which a capacitor C8-6 is electrically connected is located on a wiring WS6 that electrically connects the contact Csa6 and the electrode 603 of the piezoelectric element 60 of the ejection module 23-6.

[0295] Thus, even if the voltage value of the reference voltage signal VBS fluctuates due to the operation of any one of the discharge modules 23-1 to 23-6, the fluctuation in the voltage value is absorbed by the capacitors C8-1 to C6, thereby reducing the possibility that the voltage value of the reference voltage signal VBS supplied to each of the discharge modules 23-1 to 23-6 will fluctuate.

[0296] In the liquid ejection device 1 configured as described above, a wiring WS1 for transmitting a reference voltage signal VBS is located between a wiring WA1 for transmitting a drive signal COMA1 that drives the piezoelectric element 60 of the ejection module 23-1 so as to eject ink from the ejection module 23-1, and a wiring WB1 for transmitting a drive signal COMB1 that drives the piezoelectric element 60 of the ejection module 23-1 so as to eject ink from the ejection module 23-1. A wiring WC1 for transmitting a drive signal COMC1 that drives the piezoelectric element 60 of the ejection module 23-1 is provided on the same layer 843 as the wiring WS1 so as to prevent ink from being ejected from the ejection module 23-1. Thus, a current generated when the drive signals COMA1, COMB1, and COMC1 propagate through the wiring WA1, WB1, and WC1, flows into the ejection module 23-1, and then propagates through the wiring WS1 and returns to the drive circuits 52a1, 52b1, and 52c1. That is, currents flow in opposite directions through the wiring WA1, WB1, WC1 and the wiring WS1 on the wiring board 810. As a result, inductance components caused by currents generated when the drive signals COMA1, COMB1, COMC1 propagate are canceled out, reducing the risk of distortion of the signal waveforms of the drive signals COMA1, COMB1, COMC1 due to the inductance components.

[0297] Furthermore, in the liquid ejection device 1 of this embodiment, the wiring WS1 is located between the wiring WA1 and the wiring WB1 along the Z2 direction, and the wiring WC1, through which the drive signal COMC1 that drives the piezoelectric element 60 of the ejection module 23-1 propagates, is located in the same wiring layer as the wiring WS1 so as to prevent ink from being ejected from the ejection module 23-1. The amount of current generated when the drive signal COMC1 propagates is smaller than the amount of current generated when the drive signals COMA1 and COMB1 propagate. Therefore, the pattern width of the wiring WC1 is smaller than the pattern widths of the wiring WA1 and WB1. Furthermore, the inductance component generated by the current generated when the drive signal COMC1, which has a small current amount, propagates is smaller than the inductance component generated by the current generated when the drive signals COMA1 and COMB1 propagate. Therefore, there is little risk of distortion in the signal waveforms of the drive signals COMA1, COMB1, and COMC1 due to the inductance component generated by the current generated when the drive signal COMC1 propagates. By providing the wiring WC1 through which such a drive signal COMC1 propagates in the same wiring layer as at least one of the wirings WA1, WB1, and WS1, preferably in the same wiring layer as the wiring WS1, even when the drive circuit board 800 outputs the drive signals COMA1, COMB1, and COMC1 and the reference voltage signal VBS, the risk of distortion occurring in the signal waveforms of the drive signals COMA1, COMB1, and COMC1 supplied to the ejection module 23-1 is reduced without increasing the number of wiring layers that the wiring board 810 has.

[0298] 1.8 Variations In the liquid ejection device 1 in the first embodiment described above, it has been explained that the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 are supplied to the ejection modules 23-1 to 23-6, respectively, but this is not limited to this, and only the drive signals COMA1 to COMA6, or only the drive signals COMA1 to COMA6, and COMB1 to COMB6 may be supplied to the ejection modules 23-1 to 23-6, respectively.

[0299] Furthermore, in the liquid ejection device 1 of the first embodiment, the wiring substrate 810 has been described as being a single substrate, but it may be made up of a plurality of wiring substrates 810. In this case, one surface of the plurality of wiring substrates 810 can be regarded as a first surface, and another surface of the plurality of wiring substrates 810 can be regarded as a second surface.

[0300] 2. Second embodiment Next, a liquid ejection device 1 according to a second embodiment will be described. In describing the liquid ejection device 1 according to the second embodiment, the same components as those in the liquid ejection device 1 according to the first embodiment will be denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0301] Fig. 23 is a diagram showing an example of the electrical connection relationship of the drive circuit board 800 in the second embodiment. As shown in Fig. 23, the drive circuit board 800 in the second embodiment has resistors Rs1 to Rs6. One end of the resistor Rs1 is electrically connected to the contact Csa1, and the other end is electrically connected to the contact Csb1. In other words, the resistor Rs1 electrically connects the contact Csa1 and the contact Csb1. Similarly, resistor Rs2 has one end electrically connected to contact Csa2 and the other end electrically connected to contact Csb2, resistor Rs3 has one end electrically connected to contact Csa3 and the other end electrically connected to contact Csb3, resistor Rs4 has one end electrically connected to contact Csa4 and the other end electrically connected to contact Csb4, resistor Rs5 has one end electrically connected to contact Csa5 and the other end electrically connected to contact Csb5, and resistor Rs6 has one end electrically connected to contact Csa6 and the other end electrically connected to contact Csb6. That is, resistor Rs2 electrically connects contact Csa2 and contact Csb2, resistor Rs3 electrically connects contact Csa3 and contact Csb3, resistor Rs4 electrically connects contact Csa4 and contact Csb4, resistor Rs5 electrically connects contact Csa5 and contact Csb5, and resistor Rs6 electrically connects contact Csa6 and contact Csb6.

[0302] Thus, even if the voltage value of the reference voltage signal VBS fluctuates due to the operation of any one of the ejection modules 23-1 to 23-6, the fluctuation in the voltage value is absorbed by the capacitors C8-1 to C6 and the resistors Rs1 to Rs6, which further reduces the risk of fluctuation in the voltage value of the reference voltage signal VBS supplied to each of the ejection modules 23-1 to 23-6.

[0303] 3. Third embodiment Next, a liquid ejection device 1 according to a third embodiment will be described. In describing the liquid ejection device 1 according to the third embodiment, the same components as those in the liquid ejection devices 1 according to the first and second embodiments will be denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0304] FIG. 24 is a cross-sectional view of wiring board 810 of the third embodiment when wiring board 810 is cut along a line segment corresponding to line Bb shown in FIGS.

[0305] As shown in Figure 24, in the liquid ejection device 1 of the third embodiment, the wiring WC1 that propagates the drive signal COMC1 is provided on the same layer 844 as the wiring WB1 that propagates the drive signal COMB1, and similarly, the wiring WC2 to WC6 that propagate each of the drive signals COMC2 to COMC6 are provided on the same layer 844 as the wiring WB2 to WB6 that propagate each of the drive signals COMB2 to COMB6.

[0306] In this case, as shown in FIG. 24, the wiring WC1 is preferably provided on the same layer 844 as the wiring WB1, which carries a smaller current than the wiring WA1. Because the wiring WB1 carries a smaller current than the wiring WA1, the pattern width of the wiring WB1 can be made smaller than the pattern width of the wiring WA1. This allows the wiring WC1 to be arranged facing the wiring WA1 and the wiring WS1 along the Z2 direction. As a result, the area of ​​the wiring substrate 810 occupied by the wiring patterns transmitting the drive signals COMA1, COMB1, and COM1 and the reference voltage signal VBS to the ejection module 23-1 can be reduced, thereby enabling the miniaturization of the wiring substrate 810. In other words, the liquid ejection device 1 of the second embodiment has the same effects as the liquid ejection device 1 of the first embodiment, and also enables the miniaturization of the wiring substrate 810.

[0307] Here, as shown in the liquid ejection device 1 of the first and second embodiments, the wiring WC1 that propagates the drive signal COMC1 may be provided on at least one of the layer 842 on which the wiring WA1 that propagates the drive signal COMA1 is provided, the layer 844 on which the wiring WB1 that propagates the drive signal COMB1 is provided, and the layer 843 on which the wiring WS1 that propagates the reference voltage signal VBS is provided, thereby reducing the risk of distortion in the signal waveforms of the drive signals COMA1, COMB1, and COMC1 supplied to the ejection module 23-1 without increasing the number of wiring layers that the wiring board 810 has.

[0308] 4. Fourth embodiment Next, a liquid ejection device 1 according to a fourth embodiment will be described. In describing the liquid ejection device 1 according to the fourth embodiment, the same components as those of the liquid ejection devices 1 according to the first to third embodiments will be denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0309] FIG. 25 is a cross-sectional view of wiring board 810 of the fourth embodiment when wiring board 810 is cut along a line segment corresponding to line Bb shown in FIGS.

[0310] 25, in the liquid ejection device 1 of the fourth embodiment, the wiring substrate 810 has a layer 853 and a layer 863. The layer 853 is located between the layers 842 and 843 in the Z2 direction. The layer 863 is located between the layers 843 and 844 in the Z2 direction. The layers 853 and 863 are provided with wirings WS1 to WS6 that propagate the reference voltage signal VBS. That is, the reference voltage signal VBS propagates through the wirings WS1 to WS6 formed on the layers 843, 853, and 863.

[0311] Furthermore, each of the wirings WC1 to WC6 that propagate the drive signals COMC1 to COMC6 and are provided on layer 843 is located at least partially between the wirings WS1 to WS6 provided on layer 853 and the wirings WS1 to WS6 provided on layer 863, and is located so as to overlap with each of the wirings WA1 to WA6, each of the wirings WB1 to WB6, and each of the wirings WS1 to WS6 in a direction along the Z2 direction, which is one direction.

[0312] In the liquid ejection device 1 of the fourth embodiment configured as described above, the effective cross-sectional area of ​​the wirings WS1 to WS6 through which the reference voltage signal VBS propagates can be increased, which not only provides the same effects as the liquid ejection devices 1 of the first to third embodiments, but also further reduces the risk of fluctuations in the voltage value of the reference voltage signal VBS due to the impedance components of the wirings WS1 to WS6.

[0313] 5. Fifth embodiment Next, a liquid ejection device 1 according to a fifth embodiment will be described. In describing the liquid ejection device 1 according to the fifth embodiment, the same components as those of the liquid ejection devices 1 according to the first to fourth embodiments will be denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0314] Figure 26 is a cross-sectional view of the wiring board 810 of the fifth embodiment when the wiring board 810 is cut along a line segment corresponding to line Bb shown in Figures 15 to 21. As shown in Figure 26, in the liquid ejection device 1 of the fifth embodiment, the wiring board 810 has layers 852, 853, and 854.

[0315] Wiring lines WA1 to WA6, through which the drive signals COMA1 to COMA6 propagate, are provided on the layer 852. The layer 852 is located adjacent to the layer 842, on which the wiring lines WA1 to WA6, through which the drive signals COMA1 to COMA6 propagate, are provided, along the Z2 direction, which is one direction, and the layer 842 is located between the layer 843 and the layer 852. In this case, at least a portion of each of the wiring lines WA1 to WA6 provided on the layer 852 is arranged to overlap at least a portion of each of the wiring lines WA1 to WA6 provided on the layer 842, along the Z2 direction, which is one direction.

[0316] Wirings WB1 to WB6, through which the drive signals COMB1 to COMB6 propagate, are provided on the layer 854. The layer 854 is located adjacent to the layer 844, on which the wirings WB1 to WB6, through which the drive signals COMB1 to COMB6 propagate, are provided, along the Z2 direction, which is one direction, and the layer 844 is located between the layers 843 and 854. In this case, at least a portion of each of the wirings WB1 to WB6 provided on the layer 854 is arranged to overlap at least a portion of each of the wirings WB1 to WB6 provided on the layer 844, along the Z2 direction, which is one direction.

[0317] Wiring lines WS1 to WS6, through which the reference voltage signal VBS propagates, are provided on the layer 853. The layer 853 is located adjacent to the layer 843, on which the wiring lines WS1 to WS6, through which the reference voltage signal VBS propagates, are provided, along the Z2 direction, which is one direction. In this case, at least a portion of each of the wiring lines WS1 to WS6 provided on the layer 853 is arranged to overlap at least a portion of each of the wiring lines WS1 to WS6 provided on the layer 843, along the Z2 direction, which is one direction.

[0318] In the liquid ejection device 1 of the fifth embodiment configured as described above, the effective cross-sectional areas of the wirings WS1 to WS6 through which the reference voltage signal VBS propagates can be increased, and the effective cross-sectional areas of the wirings WA1 to WA6 through which the drive signals COMA1 to COMA6 propagate and the wirings WB1 to WB6 through which the drive signals COMB1 to COMB6 propagate can also be increased. This not only achieves the same effects as the liquid ejection device 1 of the first to fourth embodiments, but also reduces the risk of distortion in the signal waveforms of the drive signals COMA1 to COMA6 due to the impedance components of the wirings WA1 to WA6, reduces the risk of distortion in the signal waveforms of the drive signals COMB1 to COMB6 due to the impedance components of the wirings WB1 to WB6, and further reduces the risk of fluctuations in the voltage value of the reference voltage signal VBS due to the impedance components of the wirings WS1 to WS6.

[0319] Although the embodiments and modifications have been described above, the present invention is not limited to these embodiments and can be embodied in various forms without departing from the spirit of the present invention. For example, the above embodiments can be combined as appropriate.

[0320] The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects). The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects as the configurations described in the embodiments or that can achieve the same purpose. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments.

[0321] The following can be derived from the above-described embodiment.

[0322] One aspect of the liquid ejection device is a liquid ejection head having a piezoelectric element driven by a first drive signal supplied to a first electrode and a reference voltage signal supplied to a second electrode, the liquid ejection head ejecting liquid by driving the piezoelectric element; a drive circuit board that outputs the first drive signal; Equipped with The drive circuit board includes: a substrate having a plurality of wiring layers; a first drive circuit including a first circuit element having one end supplied with a ground potential and outputting the first drive signal; a first capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; a second capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; and the substrate includes a first surface and a second surface different from the first surface; The first capacitor is a chip capacitor, The second capacitor is an electrolytic capacitor, the first circuit element and the first capacitor are provided on the first surface, The second capacitor is provided on the second surface.

[0323] According to this liquid ejection device, the current generated by the first drive signal output by the first drive circuit returns to the first drive circuit via the piezoelectric element, the first capacitor, the second capacitor, and the ground potential. In this case, by providing the first drive circuit and the first capacitor, which is a chip capacitor, on the first surface of the substrate, the ground potential supplied to the first circuit element of the first drive circuit and the ground potential supplied to the first capacitor can be supplied via a wiring pattern formed on the same wiring layer. This shortens the feedback path along which the current generated by the first drive signal returns to the first drive circuit. As a result, the inductance component generated by the current generated by the first drive signal can be reduced, the risk of noise being superimposed on the current generated by the first drive signal is reduced, and the waveform accuracy of the drive signal is improved.

[0324] Furthermore, by using a chip capacitor as the first capacitor, a ceramic capacitor as the second capacitor connected in parallel to the first capacitor, and providing the second capacitor on the second surface of the board, the risk of the drive circuit board becoming larger due to the electrolytic capacitor being a relatively large component is reduced, and the risk of the characteristics of the electrolytic capacitor changing due to heat generated in the first drive circuit is reduced, resulting in improved waveform accuracy of the first drive signal and improved stability of the voltage value of the reference voltage signal VBS.

[0325] In one aspect of the liquid ejection device, the substrate includes a first wiring layer including a first ground wiring at a ground potential and a second wiring layer including a second ground wiring at a ground potential; The shortest distance between the first surface and the first wiring layer may be shorter than the shortest distance between the first surface and the second wiring layer, and the shortest distance between the second surface and the second wiring layer may be shorter than the shortest distance between the second surface and the first wiring layer.

[0326] According to this liquid ejection device, the first capacitor and the first circuit element can be electrically connected to the first ground wiring included in the first wiring layer provided near the first surface. This further shortens the feedback path along which the current generated by the first drive signal returns to the first drive circuit. This improves the waveform accuracy of the first drive signal and the stability of the voltage value of the reference voltage signal VBS.

[0327] In one aspect of the liquid ejection device, The first circuit element and the first capacitor may be electrically connected to the first ground wiring without passing through the second wiring layer.

[0328] In this liquid ejection device, the first capacitor and the first circuit element are electrically connected to the first ground wiring included in the first wiring layer without going through the second ground wiring included in the second wiring layer, thereby further shortening the feedback path along which the current generated by the first drive signal returns to the first drive circuit, thereby improving the waveform accuracy of the first drive signal and improving the stability of the voltage value of the reference voltage signal VBS.

[0329] In one aspect of the liquid ejection device, The second capacitor may be electrically connected to the second ground wiring without going through the first wiring layer.

[0330] In one aspect of the liquid ejection device, the substrate includes a third wiring layer including a reference voltage signal wiring through which the reference voltage signal propagates; At least a portion of the third wiring layer may be located between the first wiring layer and the second wiring layer.

[0331] In one aspect of the liquid ejection device, The electrical distance between the first circuit element and the first capacitor may be shorter than the electrical distance between the first circuit element and the second capacitor.

[0332] According to this liquid ejection device, by making the electrical distance between the first capacitor, which is a chip capacitor, and the first circuit element shorter than the electrical distance between the second capacitor, which is an electrolytic capacitor, and the second circuit element, it becomes easier to place the first capacitor near the first circuit element, and it is possible to further shorten the feedback path along which the current generated by the first drive signal returns to the first drive circuit, thereby improving the waveform accuracy of the first drive signal and improving the stability of the voltage value of the reference voltage signal VBS.

[0333] In one aspect of the liquid ejection device, the first driving circuit includes an amplifier circuit; The first circuit element may be an amplifying transistor included in the amplifier circuit.

[0334] According to this liquid ejection device, by shortening the electrical distance between the first capacitor and the amplifying transistor, it is possible to further shorten the feedback path along which the current generated by the first drive signal returns to the first drive circuit, thereby improving the waveform accuracy of the first drive signal and improving the stability of the voltage value of the reference voltage signal VBS.

[0335] In one aspect of the liquid ejection device, the first driving circuit includes an amplifier circuit; The first circuit element may be a capacitor for stabilizing an amplification power supply voltage supplied to the amplifier circuit.

[0336] According to this liquid ejection device, by shortening the electrical distance between the first capacitor and the stabilizing capacitor, the feedback path along which the current generated by the first drive signal returns to the first drive circuit can be further shortened, thereby improving the waveform accuracy of the first drive signal and improving the stability of the voltage value of the reference voltage signal VBS.

[0337] In one aspect of the liquid ejection device, the first driving circuit includes a demodulation circuit; The first circuit element may be a capacitor for a low-pass filter included in the demodulation circuit.

[0338] According to this liquid ejection device, by shortening the electrical distance between the first capacitor and the capacitor for the low-pass filter that outputs the drive signal, it is possible to further shorten the feedback path through which the current generated by the first drive signal returns to the first drive circuit, thereby improving the waveform accuracy of the first drive signal and improving the stability of the voltage value of the reference voltage signal VBS.

[0339] In one aspect of the liquid ejection device, The capacitance of the first capacitor may be smaller than the capacitance of the second capacitor.

[0340] According to this liquid ejection device, by using a capacitor with a large capacitance as the second capacitor, the stability of the voltage value of the reference voltage signal VBS is further improved.

[0341] In one aspect of the liquid ejection device, The size of the first capacitor in a normal direction of the substrate may be smaller than the size of the second capacitor in the normal direction.

[0342] According to this liquid ejection device, even if the second capacitor is a component larger than the first capacitor, the second capacitor is provided on the second surface of the substrate, thereby reducing the risk of the substrate becoming large.

[0343] In one aspect of the liquid ejection device, The drive circuit board includes: a second drive circuit including a second circuit element having one end supplied with a ground potential, and outputting a second drive signal to be supplied to the first electrode of the piezoelectric element; a third capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; Has, The third capacitor is a chip capacitor, the second circuit element and the third capacitor are provided on the first surface; 12. The liquid ejection device according to claim 1, wherein the liquid ejection device is a liquid ejection device.

[0344] According to this liquid ejection device, by controlling the drive of the piezoelectric element using the first drive signal and the second drive signal, it is possible to precisely control the amount of ink ejected from the liquid ejection head, thereby improving the ejection accuracy of the ink ejected from the liquid ejection head. Also, in this case, by providing a second capacitor common to the first drive circuit and the second drive circuit, the risk of the substrate becoming large is reduced.

[0345] One aspect of the drive circuit board is a drive circuit board that has a piezoelectric element driven by a first drive signal supplied to a first electrode and a reference voltage signal supplied to a second electrode, and outputs the first drive signal to a liquid ejection head that ejects liquid by driving the piezoelectric element, a substrate having a plurality of wiring layers; a first drive circuit including a first circuit element having one end supplied with a ground potential and outputting the first drive signal; a first capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; a second capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; Equipped with the substrate includes a first surface and a second surface different from the first surface; The first capacitor is a chip capacitor, The second capacitor is an electrolytic capacitor, the first circuit element and the first capacitor are provided on the first surface, The second capacitor is provided on the second surface.

[0346] According to this drive circuit board, the current generated by the first drive signal output by the first drive circuit returns to the first drive circuit via the piezoelectric element, the first capacitor, the second capacitor, and the ground potential. In this case, by providing the first drive circuit and the first capacitor, which is a chip capacitor, on the first surface of the board, the ground potential supplied to the first circuit element of the first drive circuit and the ground potential supplied to the first capacitor can be supplied via a wiring pattern formed on the same wiring layer. This shortens the feedback path along which the current generated by the first drive signal returns to the first drive circuit. As a result, the inductance component generated by the current generated by the first drive signal can be reduced, the risk of noise being superimposed on the current generated by the first drive signal is reduced, and the waveform accuracy of the drive signal is improved.

[0347] Furthermore, by using a chip capacitor as the first capacitor, a ceramic capacitor as the second capacitor connected in parallel to the first capacitor, and providing the second capacitor on the second surface of the board, the risk of the drive circuit board becoming larger due to the electrolytic capacitor being a relatively large component is reduced, and the risk of the characteristics of the electrolytic capacitor changing due to heat generated in the first drive circuit is reduced, resulting in improved waveform accuracy of the first drive signal and improved stability of the voltage value of the reference voltage signal VBS. [Explanation of symbols]

[0348] 1...liquid ejection device, 2...control unit, 3...liquid container, 4...transport unit, 5...ejection unit, 10...head drive module, 20...liquid ejection module, 23...ejection module, 30...connection member, 31...casing, 33...aggregate substrate, 34...flow path structure, 35...head substrate, 37...distribution flow path, 39...fixing plate, 41...transport motor, 42...transport roller, 50...drive signal output circuit, 52...drive circuit, 53...reference voltage output circuit, 60...piezoelectric element, 100...control circuit, 101...integrated circuit, 120...conversion circuit, 200...drive signal selection circuit, 201...integrated circuit, 10... selection control circuit, 212... shift register, 214... latch circuit, 216... decoder, 220... restoration circuit, 230... selection circuit, 232a, 232b, 232c... inverter, 234a, 234b, 234c... transfer gate, 311... opening, 313... aggregate substrate insertion portion, 315... holding member, 330... connection portion, 341... introduction portion, 343... through hole, 351... opening, 352, 353, 355... notch portion, 371... opening, 373... introduction portion, 388... wiring member, 391... opening, 500... integrated circuit, 510... modulation circuit, 512, 513... Calculator, 514... Comparator, 515... Inverter, 516... Integral attenuator, 517... Attenuator, 520... Gate drive circuit, 521, 522... Gate drivers, 550... Amplification circuit, 560... Demodulation circuit, 570, 572... Feedback circuit, 590... Power supply circuit, 600... Discharge portion, 601... Piezoelectric element, 602, 603... Electrode, 610... Vibration plate, 611... Lead electrode, 620... Compliance substrate, 621... Sealing film, 622... Fixed substrate, 623... Nozzle plate, 623a... Liquid ejection surface, 630... Communication plate, 641... Protective substrate, 642... Flow path forming substrate, 643 ...through hole, 644...protective space, 660...case, 661...inlet path, 662...connection port, 665...recess, 710...heat sink, 711...bottom, 712, 713...side, 714...opening, 715-717...protrusion, 718...fin portion, 720...thermal conduction member group, 730, 740, 750, 760...thermal conduction member, 770...cooling fan, 780...screw, 800...drive circuit board, 810...wiring board, 811-814...side, 820...through hole, 831, 832...surface, 840-845, 852-854, 863...layer, C1-C9...condenser, CB...pressure chamber, CN1,CN2...connection part, Cha1 to Cha6, Chb1 to Chb6, Csa1 to Csa6, Csb1 to Csb6...contacts, D1...diode, FC...wiring member, L1...inductor, Ln1, Ln2...nozzle array, M1, M2...transistor, MN...manifold, N...nozzle, P...medium, R1 to R6...resistor, RA, RB...supply communication path, RK1, RK2...pressure chamber communication path, RR...nozzle communication path, RX...connection communication path, Rs1 to Rs6...resistor, Su1, Su2...flow path plate, WA1 to WA6, WB1 to WB6, WC1 to WC6, WG1, WG2, WH1 to WH6, WHc, WS1 to WS6, WSc...wiring,

Claims

1. Driven by a first drive signal supplied to the first electrode and a reference voltage signal supplied to the second electrode. a liquid ejection head having a piezoelectric element that is driven by the piezoelectric element and that ejects liquid; a drive circuit board that outputs the first drive signal; Equipped with The drive circuit board includes: a substrate having a plurality of wiring layers; a first circuit element having one end supplied with a ground potential, and outputting the first drive signal; a first drive circuit; A first capacitor has one end electrically connected to the second electrode and the other end to which a ground potential is supplied. and a second capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; and and The substrate has a first surface, a second surface different from the first surface, and a first ground surface at a ground potential. a first wiring layer including a ground wiring, and a second wiring layer including a second ground wiring at a ground potential; Including, The first capacitor is a chip capacitor, The second capacitor is an electrolytic capacitor, the first circuit element and the first capacitor are provided on the first surface, the second capacitor is provided on the second surface, The shortest distance between the first surface and the first wiring layer is the shortest distance between the first surface and the second wiring layer. The shortest distance between the second surface and the second wiring layer is shorter than the distance between the second surface and the first wiring layer. shorter than the shortest distance to the layer, A liquid ejection device characterized by:

2. The first circuit element and the first capacitor are connected to the first group without the second wiring layer. Electrically connected to the round wiring, The liquid ejection device according to claim 1 .

3. The second capacitor is electrically connected to the second ground wiring without passing through the first wiring layer. connected to 3. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

4. the substrate includes a third wiring layer including a reference voltage signal wiring through which the reference voltage signal propagates; At least a part of the third wiring layer is located between the first wiring layer and the second wiring layer. are 4. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

5. The electrical distance between the first circuit element and the first capacitor is Shorter than the electrical distance to the second capacitor 5. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

6. the first driving circuit includes an amplifier circuit; the first circuit element is an amplifying transistor included in the amplifier circuit; 6. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

7. the first driving circuit includes an amplifier circuit; The first circuit element is a capacitor for stabilizing the power supply voltage for amplification supplied to the amplifier circuit. - is, 6. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

8. the first driving circuit includes a demodulation circuit; The first circuit element is a capacitor for a low-pass filter included in the demodulation circuit. Ru, 6. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

9. The capacitance of the first capacitor is smaller than the capacitance of the second capacitor.

9. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

10. The size of the first capacitor in the normal direction of the substrate is smaller than the size of the second capacitor; 9. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

11. The drive circuit board includes: a second circuit element having one end supplied with a ground potential; a second drive circuit that outputs a second drive signal that is supplied to the a third capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; and Has, The third capacitor is a chip capacitor, the second circuit element and the third capacitor are provided on the first surface.

11. The liquid ejection device according to claim 1.

12. Driven by a first drive signal supplied to the first electrode and a reference voltage signal supplied to the second electrode. a liquid ejection head that ejects liquid by driving the piezoelectric element, a drive circuit board that outputs the first drive signal, a substrate having a plurality of wiring layers; a first circuit element having one end supplied with a ground potential, and outputting the first drive signal; a first drive circuit; A first capacitor has one end electrically connected to the second electrode and the other end to which a ground potential is supplied. and a second capacitor having one end electrically connected to the second electrode and the other end to which a ground potential is supplied; and Equipped with The substrate has a first surface, a second surface different from the first surface, and a first ground surface at a ground potential. a first wiring layer including a ground wiring, and a second wiring layer including a second ground wiring at a ground potential; Including, The first capacitor is a chip capacitor, The second capacitor is an electrolytic capacitor, the first circuit element and the first capacitor are provided on the first surface, the second capacitor is provided on the second surface, The shortest distance between the first surface and the first wiring layer is the shortest distance between the first surface and the second wiring layer. The shortest distance between the second surface and the second wiring layer is shorter than the distance between the second surface and the first wiring layer. shorter than the shortest distance to the layer, A drive circuit board characterized by:

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