Liquid ejection device and head drive circuit

Abstract

To provide a liquid discharge device that can radiate heat generated in a driving circuit more efficiently.SOLUTION: A liquid discharge device comprises a substrate having a first through-hole, a first driving circuit, a second driving circuit, a third driving circuit, a metallic frame, and a first screw that is inserted through the first through-hole to mount the metallic frame on the substrate. The first driving circuit outputs a first driving signal for driving a first piezoelectric element so that a discharge head discharges a first discharge amount of liquid. The second driving circuit outputs a second driving signal for driving the first piezoelectric element so that the discharge head discharges a second discharge amount of liquid. The third driving circuit outputs a third driving signal for driving the first piezoelectric element so that the discharge head does not discharge liquid. The first driving circuit, the second driving circuit and the third driving circuit are positioned side by side along one direction in this order in the substrate. The first through-hole is positioned between the first driving circuit and the second driving circuit in the one direction.SELECTED DRAWING: Figure 12

Description

[Technical Field]

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

[0002] A known liquid ejection device, which forms images or documents on a medium by ejecting ink as a liquid, has a drive element provided corresponding to each of a plurality of nozzles that eject the liquid, and when the drive element is driven, ink is ejected from the corresponding nozzle. The drive elements used in such liquid ejection devices are provided corresponding to each of the plurality of nozzles. Therefore, the drive circuit must output a drive signal containing a sufficient current to simultaneously drive the plurality of drive elements. In particular, in a liquid ejection device that uses a piezoelectric element as the drive element, the piezoelectric element is electrically a capacitive load similar to a capacitor, and therefore, in order to drive the piezoelectric element with precision, it is necessary to supply a sufficient current to the piezoelectric element.

[0003] However, the drive elements and drive circuits generate a large amount of heat because they output drive signals containing large currents. If the heat generated by the drive circuits is transferred to the liquid being ejected, the physical properties of the liquid may change. Furthermore, if the heat generated by the drive circuits is transferred to the electronic components of the drive circuits, the characteristics of the electronic components may change. In other words, the heat generated by the drive circuits may reduce the operational stability of the drive circuits and may also change the physical properties of the liquid, thereby degrading the liquid ejection characteristics of the liquid ejection device. Therefore, various heat dissipation structures have been considered for liquid ejection devices to efficiently dissipate heat from the drive circuits.

[0004] For example, Patent Document 1 discloses a liquid ejection device in which a circuit board on which multiple drive circuits are arranged, each of which outputs a drive signal to drive a piezoelectric element as a drive element, is housed in a case, and a technology is disclosed in which the drive circuit that generates the most heat is arranged near the air intake of the case, thereby increasing the heat dissipation efficiency of the drive circuit and improving the stability of its operation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-099835 Summary of the Invention [Problem to be solved by the invention]

[0006] In response to recent market demands for even faster ink ejection speeds, liquid ejection devices have been shortening the cycle of the drive waveforms included in the drive signals that drive drive elements. At the same time, the amount of ink ejected per drive waveform has been increasing, with the aim of achieving the formation of dots of sufficient size even with the shortened cycle drive waveform. This has resulted in an increase in the amount of current generated by the propagation of the drive signal, and an increase in the amount of heat generated by the drive circuit. The heat dissipation technique described in Patent Document 1 alone is insufficient to address this increase in the amount of heat generated by the drive circuit, and further improvements are needed to more efficiently dissipate the heat generated by the drive circuit. [Means for solving the problem]

[0007] One aspect of the liquid ejection device according to the present invention is a discharge head that discharges liquid in response to driving of a first piezoelectric element; a substrate having a first through hole; a first drive circuit, a second drive circuit, and a third drive circuit provided on the substrate; a metal frame attached to the substrate; a first screw that passes through the first through hole and attaches the metal frame to the substrate; Equipped with the first drive circuit outputs a first drive signal that drives the first piezoelectric element so that the ejection head ejects a first ejection amount of liquid; the second drive circuit outputs a second drive signal that drives the first piezoelectric element so that the ejection head ejects a second amount of liquid; the third drive circuit outputs a third drive signal that drives the first piezoelectric element so as not to cause the ejection head to eject liquid; the first drive circuit, the second drive circuit, and the third drive circuit are arranged side by side in one direction on the substrate in the order of the first drive circuit, the second drive circuit, and the third drive circuit; The first through hole is located between the first drive circuit and the second drive circuit in the one direction.

[0008] One aspect of the head drive circuit according to the present invention is a head drive circuit that drives a discharge head that discharges liquid in response to driving of a first piezoelectric element, a substrate having a first through hole; a first drive circuit, a second drive circuit, and a third drive circuit provided on the substrate; a metal frame attached to the substrate; a first screw that passes through the first through hole and attaches the metal frame to the substrate; Equipped with the first drive circuit outputs a first drive signal that drives the first piezoelectric element so that the ejection head ejects a first ejection amount of liquid; the second drive circuit outputs a second drive signal that drives the first piezoelectric element so that the ejection head ejects a second amount of liquid; the third drive circuit outputs a third drive signal that drives the first piezoelectric element so as not to cause the ejection head to eject liquid; the first drive circuit, the second drive circuit, and the third drive circuit are arranged side by side in one direction on the substrate in the order of the first drive circuit, the second drive circuit, and the third drive circuit; The first through hole is located between the first drive circuit and the second drive circuit in the one direction. [Brief explanation of the drawings]

[0009] [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] FIG. 2 is a diagram showing an example of a cross section of a discharge module. [Figure 12] FIG. 2 is a diagram illustrating an example of the structure of a head driving module. [Figure 13] FIG. 2 is a diagram showing an example of a cross-sectional structure of a wiring substrate on which a plurality of drive circuits are provided. [Figure 14] FIG. 2 is a diagram showing an example of the configuration of a first layer of a wiring board. [Figure 15] FIG. 10 is a diagram showing an example of a wiring pattern provided on a second layer of the wiring board. [Figure 16] FIG. 10 is a diagram showing an example of a wiring pattern provided on a third layer of a wiring board. [Figure 17] FIG. 10 is a diagram showing an example of a wiring pattern provided on a fourth layer of the wiring board. [Figure 18]FIG. 10 is a diagram illustrating an example of the configuration of a first layer of a wiring board according to a second embodiment. [Figure 19] FIG. 10 is a diagram showing an example of a wiring pattern provided on a second layer of a wiring board according to a second embodiment. [Figure 20] 10A and 10B are diagrams illustrating an example of a wiring pattern provided on a third layer of the wiring board according to the second embodiment. [Figure 21] 10A and 10B are diagrams illustrating an example of a wiring pattern provided on a fourth layer of the wiring board according to the second embodiment. [Figure 22] FIG. 10 is a diagram showing an example of the configuration of a first layer of a wiring board according to a third embodiment. [Figure 23] 10A and 10B are diagrams illustrating an example of a wiring pattern provided on a second layer of a wiring board according to a third embodiment. [Figure 24] 10A and 10B are diagrams illustrating an example of a wiring pattern provided on a third layer of a wiring board according to a third embodiment. [Figure 25] 10A and 10B are diagrams illustrating an example of a wiring pattern provided on a fourth layer of the wiring board according to the third embodiment. [Figure 26] FIG. 11 is a diagram showing an example of the configuration of a first layer of a wiring board according to a modified example of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] 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.

[0012] 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.

[0013] 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 to control each element of the liquid ejection device 1 based on image data supplied from an external device such as a host computer (not shown) provided outside the liquid ejection device 1.

[0014] 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.

[0015] 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, thereby transporting the medium P along the transport direction.

[0016] 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. The head driving module 10 controls the operation of the liquid ejection module 20 based on the image information signal IP input from the control unit 2, 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.

[0017] The liquid ejection device 1 in the first embodiment constitutes a so-called line-type inkjet printer that is capable of ejecting ink to the entire area in the width direction of the transported medium P by arranging the liquid ejection modules 20 of each of the multiple ejection units 5 in a line along the main scanning direction so that the width is equal to or greater than the width of the medium P. Note that the liquid ejection device 1 is not limited to a line-type inkjet printer.

[0018] Next, a description will be given of the schematic configuration of the 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 wiring member 30.

[0019] The wiring member 30 is a flexible member for electrically connecting the head driving module 10 and the liquid ejection module 20, and is, for example, a flexible printed circuit (FPC) or a flexible flat cable (FFC). Note that the head driving module 10 and the liquid ejection module 20 may be electrically connected by, for example, a BtoB (Board to Board) connector without using an FPC or FFC, or may be electrically connected by using a BtoB connector in combination with an FPC or FFC.

[0020] The head driving module 10 includes a control circuit 100, driving signal output circuits 50-1 to 50-m, and a conversion circuit 120.

[0021] 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.

[0022] 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 the base data signal dDATA 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 the data signal DATA to the liquid ejection module 20. Note that 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 the data signal DATA to the liquid ejection module 20, or may output a part or all of the input base data signal dDATA to the liquid ejection module 20 as a single-ended data signal DATA.

[0023] 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.

[0024] Here, each of the drive circuits 52a, 52b, 52c is only required to generate the drive signals COMA1, COMB1, COMC1 by amplifying the waveforms defined by the input basic drive signals dA1, dB1, dC1, respectively, and may include a class A amplifier circuit, a class B amplifier circuit, or a class AB amplifier circuit instead of or in addition to the class D amplifier circuit. Also, each of the basic drive signals dA1, dB1, dC1 may be an analog signal as long as it can define the waveform of the corresponding drive signal COMA1, COMB1, COMC1.

[0025] The drive signal output circuit 50-1 also has a reference voltage output circuit 53. The reference voltage output circuit 53 generates a reference voltage signal VBS1 of a constant potential that indicates the reference potential of a piezoelectric element 60 (described later) that the liquid discharging module 20 has, and outputs the signal to the liquid discharging module 20. This reference voltage signal VBS1 may be, for example, ground potential or a constant potential such as 5.5 V or 6 V. Here, the constant potential includes cases where the potential can be considered to be approximately constant when various fluctuations are taken into consideration, such as fluctuations in potential caused by the operation of peripheral circuits, fluctuations in potential caused by variations in circuit elements, and fluctuations in potential caused by the temperature characteristics of circuit elements.

[0026] The drive signal output circuits 50-2 to 50-m have the same configuration as the drive signal output circuit 50-1, except that the signals they input and output are different. That is, the drive signal output circuits 50-j (j is any of 1 to m) each include a circuit equivalent to the drive circuits 52a, 52b, 52c, and a circuit equivalent to the reference voltage output circuit 53, and generate drive signals COMAj, COMBj, COMCj and a reference voltage signal VBSj based on the basic drive signals dAj, dBj, dCj input from the control circuit 100, and output them to the liquid ejection module 20.

[0027] Here, the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50-1 and the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50-j have the same configuration, and when there is no need to distinguish between them in the following description, they may be simply referred to as drive circuits 52. In this case, the description will be given assuming that the drive circuit 52 generates a drive signal COM based on the basic drive signal do and outputs it to the liquid ejection module 20. Furthermore, when distinguishing between the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50-1 and 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, 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.

[0028] The liquid ejection module 20 includes a restoration circuit 220 and ejection modules 23-1 to 23-m.

[0029] The restoration circuit 220 restores the data signal DATA to a single-ended signal, separates it into signals corresponding to the respective discharge modules 23-1 to 23-m, and outputs them to the corresponding discharge modules 23-1 to 23-m.

[0030] 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 corresponding to the ejection module 23-1, and outputs them to the ejection module 23-1. Also, the restoration circuit 220 restores and separates the data signal DATA to generate a clock signal SCKj, a print data signal SIj, and a latch signal LATj corresponding to the ejection module 23-j, and outputs them to the ejection module 23-j.

[0031] As described above, the restoration circuit 220 restores the data signal DATA, which is a differential signal output by the head driving module 10, to a single-ended signal, and separates and outputs the restored signal into signals corresponding to the ejection modules 23-1 to 23-m. As a result, the restoration circuit 220 generates 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, and outputs them to the corresponding ejection modules 23-1 to 23-m. 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 a common signal for the ejection modules 23-1 to 23-m.

[0032] Here, in view of the fact 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 control circuit 100 is a differential signal corresponding to the clock signals SCK1-SCKm, the print data signals SI1-SIm, and the latch signals LAT1-LATm, and the original data signal dDATA on which the data signal DATA is based includes 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 that the liquid ejection module 20 has.

[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 VBS1, 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, and supplies the drive signal VOUT to one end of the piezoelectric element 60 included in the corresponding ejection section 600. At this time, the reference voltage signal VBS1 is supplied to the other end of the piezoelectric element 60. The piezoelectric element 60 is driven by the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBS1 supplied to the other end. As a result, ink 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 drive signals COMAj, COMBj, and COMCj, a reference voltage signal VBSj, a clock signal SCKj, a print data signal SIj, and a 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, and supplies the drive signal VOUT to one end of the piezoelectric element 60 included in the corresponding ejection section 600. At this time, the reference voltage signal VBSj is supplied to the other end of the piezoelectric element 60. The piezoelectric element 60 is driven by the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBSj supplied to the other end. As a result, ink is ejected from the corresponding ejection section 600 .

[0037] As described above, in the liquid ejection device 1 of the first embodiment, 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 ejection of ink from the liquid ejection module 20 of the ejection unit 5. This allows the liquid ejection device 1 to land a desired amount of ink at a desired position on the medium P, forming a desired image 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 reference voltage signals VBS1 to VBSm as reference voltage signals VBS, 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 a piezoelectric element 60, causes the ejection section 600 corresponding to that piezoelectric element 60 to eject a predetermined amount of ink.

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

[0042] That is, 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, and 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. 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 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 in conjunction with the propagation of the drive signal COMA is greater than the amount of current generated in conjunction with the propagation of the drive signal COMB.

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

[0044] That is, 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. Therefore, 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, and therefore 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 values ​​of the trapezoidal waveforms Adp, Bdp, and Cdp are all the same, at voltage Vc. In other words, the trapezoidal waveforms Adp, Bdp, and Cdp are signal waveforms that each start and end at voltage Vc.

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

[0047] As described above, 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 amount of ink that is relatively large, 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.

[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 propagated, etc. That is, the drive signals COMA1 to COMAm may each include a different signal waveform, and the amount of ink ejected from the ejection unit 600 including the piezoelectric element 60 to which the drive signal COMA1 is supplied may differ from the amount of ink ejected from the ejection unit 600 including the piezoelectric element 60 to which the drive signal COMAj is supplied. Similarly, the drive signals COMB1 to COMBm may each include a different signal waveform, and the amount of ink ejected from the ejection unit 600 including the piezoelectric element 60 to which the drive signal COMB1 is supplied may differ from the amount of ink ejected from the ejection unit 600 including the piezoelectric element 60 to which the drive signal COMBj is supplied. Similarly, the drive signals COMC1 to COMCm may each contain a different signal waveform, and the amount of displacement that occurs in the piezoelectric element 60 when the drive signal COMC1 is supplied may be different from the amount of displacement that occurs in the piezoelectric element 60 when the drive signal COMCj is supplied.

[0049] Next, a description will be given of the configuration and operation of the drive signal selection circuit 200, which outputs the drive signal VOUT by selecting or deselecting each of the drive signals COMA, COMB, and COMC. 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 sections 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 total number of ejection sections 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 serially input 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 is stopped, 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 between the n cascaded shift registers 212, they are denoted 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] Each of the n decoders 216 decodes the 2-bit print data [SIH, SIL] latched by the corresponding latch circuit 214 and outputs selection signals S1, S2, and S3 at 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 at logic levels determined by the latched 2-bit print data [SIH, SIL] and the decoded content shown in FIG. 5. For example, in the first embodiment, if the 2-bit print data [SIH, SIL] latched by the corresponding latch circuit 214 is input as [1, 0], the decoder 216 sets the logic levels of the selection signals S1, S2, and S3 to L, H, and L levels during period T.

[0055] 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 and the drive signals COMA, COMB, COMC, thereby generating a drive signal VOUT and outputting 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 of the transfer gate 234a, which is not marked with a circle, and is logically inverted by the inverter 232a and input to the negative control terminal of the transfer gate 234a, which is marked with a circle. The drive signal COMA is also supplied to the input terminal of the transfer gate 234a. When the input selection signal S1 is at a high level, the transfer gate 234a establishes electrical continuity between its input terminal and output terminal, and when the input selection signal S1 is at a low level, the transfer gate 234a establishes electrical continuity between its input terminal and output terminal. That is, when the selection signal S1 is at a high level, the transfer gate 234a outputs the drive signal COMA to the output terminal, and when the selection signal S1 is at a low 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 of the transfer gate 234b (not marked with a circle), and is logically inverted by the inverter 232b and input to a negative control terminal of the transfer gate 234b (marked with a circle). The drive signal COMB is also supplied 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, whereas 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 its 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 its output terminal.

[0059] The selection signal S3 is input to the positive control terminal of the transfer gate 234c (not marked with a circle), and is logically inverted by the inverter 232c and input to the negative control terminal of the transfer gate 234c (marked with a circle). The drive signal COMC is also supplied 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, whereas 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] 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 supplied to the commonly connected output terminals of the transfer gates 234a, 234b, and 234c. The selection circuit 230 outputs the signal supplied to this commonly connected output terminal as a drive signal VOUT to the corresponding ejection unit 600.

[0061] The operation of the drive signal selection circuit 200 will now be described. Fig. 7 is a diagram for explaining the operation of the drive signal selection circuit 200. The print data signal SI is input serially in synchronization with the clock signal SCK and is transferred sequentially by the shift registers 212 corresponding to the ejection units 600. Then, 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 corresponding shift registers 212.

[0062] Thereafter, when the latch signal LAT rises, the 2-bit print data [SIH, SIL] held in the shift register 212 is latched all at once by the latch circuit 214. 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 decoder 216 outputs selection signals S1, S2, and S3 of logical levels according to the dot size defined by the latched 2-bit print data [SIH, SIL].

[0064] Specifically, when the 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, 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 and outputs a drive signal VOUT corresponding to a "large dot LD." Furthermore, when the 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, 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 and outputs a drive signal VOUT corresponding to a "small dot SD." Furthermore, when the 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, or Cdp during the period T, and outputs a drive signal VOUT corresponding to "non-ejection ND" at a constant voltage Vc. Furthermore, when the print data [SIH, SIL] is [0,0], the decoder 216 outputs the logical levels of the selection signals S1, S2, and S3 to the selection circuit 230 as L, L, and H levels during the period T. As a result, the selection circuit 230 selects the trapezoidal waveform Cdp during the period T, and outputs a drive signal VOUT corresponding to "micro-vibration BSD."

[0065] 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 selection circuit 230 outputs a constant drive signal VOUT at voltage Vc, this includes a 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.

[0066] 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.

[0067] 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.

[0068] 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 includes a DAC (Digital to Analog Converter) 511, a modulation circuit 510, a gate drive circuit 520, and a power supply circuit 590.

[0069] The power supply circuit 590 generates voltage signals DAC_HV and DAC_LV and supplies them to the DAC 511. The DAC 511 converts the digital reference drive signal do, which defines the signal waveform of the input drive signal COM, 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. Here, 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. In other words, the voltage signal DAC_HV is a reference voltage on the high-voltage side of the DAC 511, and the voltage signal DAC_LV is a reference voltage on the low-voltage side of the DAC 511. The analog reference drive signal ao output by the DAC 511 is amplified to form the drive signal COM. In other words, the reference drive signal ao corresponds to a target signal for the drive signal COM before amplification.

[0070] 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.

[0071] 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 also 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 integrated voltage to the positive input terminal of the adder 513.

[0072] 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 outputs to the comparator 514 a voltage signal Os obtained by subtracting the voltage input to the negative input terminal from the voltage input to the positive input terminal.

[0073] The comparator 514 outputs a modulated signal Ms that is obtained by pulse-modulating the voltage signal Os output from the adder 513. Specifically, the comparator 514 outputs a modulated signal Ms that goes to H level when the voltage value of the voltage signal Os output 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. The thresholds Vth1 and Vth2 are set to have the relationship threshold Vth1 => threshold Vth2.

[0074] The modulation signal Ms output from the comparator 514 is supplied to a gate driver 521 included in the gate drive circuit 520, and after its logical level is inverted by an inverter 515, is supplied to a gate driver 522 included in the gate drive circuit 520. That is, signals of logical levels having an exclusive relationship are input to the gate drivers 521 and 522. Here, strictly speaking, the logical levels of the signals supplied to the gate drivers 521 and 522 do not become H level at the same time, and more specifically, this means that the transistors M1 and M2 included in the amplifier circuit 550 described below do not turn on at the same time. Therefore, the modulation circuit 510 may include a timing control circuit for controlling the timing of the modulation signal Ms supplied to the gate driver 521 and the signal obtained by inverting the logical level of the modulation signal Ms supplied to the gate driver 522.

[0075] 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.

[0076] Specifically, the gate driver 521 receives a high-level power supply voltage via a terminal Bst and a low-level power supply voltage 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 anode of the diode D1 is supplied with the voltage Vm, a DC voltage. Therefore, the potential difference between the terminals Bst and Sw is approximately equal to the voltage Vm. As a result, the gate driver 521 outputs an amplification control signal Hgd from the terminal Hdr, which has a voltage value higher than that of the terminal Sw by the voltage Vm, in accordance with the input modulation signal Ms.

[0077] 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.

[0078] Specifically, a voltage Vm is supplied to the high side of the power supply voltage of the gate driver 522, and a ground potential of, for example, 0 V is supplied to the low side via a terminal Gnd. The gate driver 522 then outputs an amplification control signal Lgd from a terminal Ldr, which has a voltage value that is higher than that of the terminal Gnd by the voltage Vm, in accordance with a signal obtained by inverting the logical level of the input modulation signal Ms.

[0079] The amplifier circuit 550 includes a transistor M1 and a transistor M2.

[0080] The transistor M1 is a surface-mounted field effect transistor (FET), and a voltage VHV, which is a DC voltage of, for example, 42 V, is supplied to the drain of the transistor M1 as an amplified voltage. 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 supplied 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.

[0081] 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 supplied to the gate of the transistor M2. The ground potential is supplied to the source of the transistor M2.

[0082] That is, the drive circuit 52 includes surface-mounted transistors M1 and M2. In the amplifier circuit 550 configured as described above, when the transistor M1 is controlled to be off and the transistor M2 is controlled to be on, the potential of the node to which the terminal Sw is connected is ground potential. Therefore, a voltage Vm is supplied to the terminal Bst. On the other hand, when the transistor M1 is controlled to be on and the transistor M2 is controlled to be off, the potential of the node to which the terminal Sw is connected is voltage VHV. Therefore, a voltage signal having a potential of 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 the potential of the terminal Sw changes to 0 V or voltage VHV depending on the operation of the transistors M1 and M2, thereby supplying an amplification control signal Hgd to the gate of the transistor M1, whose L level is the potential of voltage VHV and whose H level is the potential of voltage VHV+voltage Vm.

[0083] On the other hand, the gate driver 522 that drives the transistor M2 supplies an amplification control signal Lgd, whose L level is the ground potential and whose H level is the potential of the voltage Vm, to the gate of the transistor M2, regardless of the operation of the transistors M1 and M2.

[0084] 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.

[0085] 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. 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 output from the amplifier circuit 550 by smoothing it using the low-pass filter, and outputs the demodulated signal as the drive signal COM. That is, the drive signal COM is output from one end of the inductor L1 included in the demodulation circuit 560.

[0086] 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.

[0087] The feedback circuit 572 includes capacitors C2, C3, and C4 and resistors R5 and R6. One end of the capacitor C2 is supplied with the drive signal COM, and the other end is connected to one end of the resistor R5 and one end of the resistor R6. The other end of the resistor R5 is supplied with ground potential. This allows the capacitors C2 and R5 to function as a high-pass filter. The cutoff frequency of this high-pass filter is set to, for example, approximately 9 MHz. The other end of the resistor R6 is connected to one end of the capacitor C4 and one end of the capacitor C3. The other end of the capacitor C3 is supplied with ground potential. This allows the resistors R6 and C3 to function as a low-pass filter. The cutoff frequency of this low-pass filter is set to, for example, approximately 160 MHz. 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.

[0088] 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.

[0089] 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 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 terminal Vfb has a large delay. Therefore, feedback via 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, as shown in Figure 8, a path is provided via terminal Ifb that feeds back the high-frequency components of the drive signal COM, separate from the path via terminal Vfb, thereby reducing the delay in the overall circuit. 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 terminal Ifb is not provided.

[0090] 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.

[0091] 1.4 Liquid Dispensing Module Configuration Next, the structure of the liquid ejection module 20 will be described with reference to FIGS. 9 to 11. FIG. 9 is a diagram illustrating the structure of the liquid ejection module 20. In describing the structure of the liquid ejection 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 leading end 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 leading end 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 leading end side thereof as the +Z1 side. In the following description, the liquid ejection module 20 included in the liquid ejection device 1 according to the first embodiment will be described as having six ejection modules 23. When distinguishing between the six ejection modules 23, the six ejection modules 23 will be referred to as ejection modules 23-1 to 23-6.

[0092] 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.

[0093] 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, and 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 channel 661 included in the discharging module 23 and also passes through the nozzle N1 and nozzle N2.

[0094] 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 number of nozzles N1 and the number of nozzles N2 in the discharge module 23 will be described as being the same. That is, the discharge module 23 will be described as having 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.

[0095] 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 .

[0096] 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.

[0097] 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.

[0098] 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 passages that correspond to the pressure chambers CB1 and CB2, respectively.

[0099] 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.

[0100] 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.

[0101] A vibration plate 610 is positioned on the surface on the +Z1 side of the flow path forming substrate 642. Furthermore, two rows of piezoelectric elements 60 are formed on the surface on the +Z1 side of the vibration plate 610, corresponding to the nozzles N1 and N2. One electrode of the piezoelectric element 60 and the piezoelectric layer are formed for each pressure chamber CB, and the other electrode of the piezoelectric element 60 is configured as a common electrode shared by the pressure chambers CB. A drive signal VOUT is supplied from the drive signal selection circuit 200 to one electrode of the piezoelectric element 60, and a reference voltage signal VBS is supplied to the other electrode of the piezoelectric element 60, which is a common electrode.

[0102] 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. The end of a lead electrode 611 drawn from the electrode of the piezoelectric element 60 is extended so as to be exposed inside the through hole 643. The wiring member 388 is electrically connected to the end of the lead electrode 611 exposed inside the through hole 643.

[0103] A case 660 that defines a portion of a manifold MN that communicates with the multiple pressure chambers CB is fixed to the protective substrate 641 and the communicating plate 630. 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. When the flow path forming substrate 642 and the like are accommodated in the recess 665, the opening surface on the -Z1 side of the recess 665 is sealed by the communicating plate 630. As a result, supply communication channels RB1 and RB2 are defined on the outer periphery of the flow path forming substrate 642 by the case 660, the flow path forming substrate 642, and the protective substrate 641. 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.

[0104] 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.

[0105] An introduction path 661 for supplying ink to the manifold MN is provided in the case 660. The case 660 also has 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.

[0106] 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. In addition, 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.

[0107] In the ejection module 23 configured as described above, the drive signal VOUT output by the drive signal selection circuit 200 and the reference voltage signal VBS are supplied to the piezoelectric element 60 via the wiring member 388. The piezoelectric element 60 is driven by a change in the potential difference between the drive signal VOUT and the reference voltage signal VBS. As the piezoelectric element 60 is driven, the vibration plate 610 is displaced vertically, changing the internal pressure of the pressure chamber CB. The change in the internal pressure of the pressure chamber CB causes ink stored in the pressure chamber CB to be ejected from the corresponding nozzle N. In the ejection module 23, the configuration including the nozzle N, the nozzle communication channel RR, the pressure chamber CB, the piezoelectric element 60, and the vibration plate 610 corresponds to the aforementioned ejection unit 600. In other words, the ejection module 23 includes a piezoelectric element 60 and has a plurality of ejection units 600 that eject ink in response to the driving of the piezoelectric element 60.

[0108] Returning to FIG. 9 , the fixing plate 39 is located on the −Z1 side of the discharge modules 23. The fixing plate 39 fixes six discharge modules 23. Specifically, the fixing plate 39 has six openings 391 that penetrate the fixing plate 39 along the Z2 direction. The liquid ejection surfaces 623a of the discharge modules 23 are exposed from each of the six openings 391. That is, the six discharge modules 23 are fixed to the fixing plate 39 so that the liquid ejection surfaces 623a are exposed from the corresponding openings 391.

[0109] 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 these six openings 371.

[0110] 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, which will be described later. The head substrate 35 also has four openings 351 and cutouts 352 and 353. The wiring members 388 of the discharge modules 23-2 to 23-5 are inserted into the four openings 351. The wiring members 388 of the discharge modules 23-2 to 23-5 that have passed through the four openings 351 are 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 cutout 352, and the wiring member 388 of the discharge module 23-6 passes through the cutout 353. The wiring members 388 of the ejection 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.

[0111] 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.

[0112] 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 four inlet ports 373 communicate with flow path holes (not shown) formed on the -Z1 side surface of the flow path structure 34. The flow path structure 34 also includes through holes 343 that penetrate the flow path structure 34 along the Z1 direction. A wiring member FC that electrically connects to the head substrate 35 is inserted through the through holes 343. Inside the flow path structure 34, in addition to an ink flow path that connects the introduction section 341 and a flow path hole (not shown) formed on the surface on the -Z1 side, a filter or the like may be provided to capture foreign matter contained in the ink flowing through the ink flow path.

[0113] 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.

[0114] 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).

[0115] The holding member 315 holds the aggregate substrate 33 with a portion of the aggregate substrate 33 inserted through the aggregate substrate insertion portion 313. The aggregate substrate 33 is provided with a connection portion 330. Various signals such as the data signal DATA, drive signals COMA, COMB, COMC, reference voltage signal VBS, and other power supply voltages output by the head drive module 10 are input to the connection portion 330 via wiring member 30. In addition, a wiring member FC included in the head substrate 35 is electrically connected to the aggregate substrate 33. This electrically connects the aggregate substrate 33 and the head substrate 35. A semiconductor device including the restoration circuit 220 described above may be provided on this aggregate substrate 33. Note that Figure 9 illustrates a case where the assembly substrate 33 has one connection portion 330, but if the liquid ejection device 1 has multiple wiring members 30 and various signals such as the data signal DATA, drive signals COMA, COMB, COMC, reference voltage signal VBS, and other power supply voltages output by the head drive module 10 are input to the assembly substrate 33 via multiple wiring members 30, the assembly substrate 33 may have multiple connection portions 330 corresponding to each of the multiple wiring members 30.

[0116] 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, thereby supplying ink stored in the liquid container 3. The ink supplied to the liquid ejection module 20 is then 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 via the four introduction portions 373 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.

[0117] The head driving module 10 and the liquid ejection module 20 are electrically connected by one or more wiring members 30. This allows the liquid ejection module 20 to be supplied with various signals, including the drive signals COMA, COMB, and COMC, the reference voltage signal VBS, and the data signal DATA, output by the head driving module 10. The various signals, including the drive signals COMA, COMB, and COMC, 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 the ejection modules 23-1 to 23-6, respectively, from the data signal DATA. 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 these signals to the piezoelectric elements 60 included in the corresponding ejection units 600. As a result, the piezoelectric element 60 is driven, and the ink stored in the pressure chamber CB is ejected.

[0118] That is, the liquid ejection module 20 includes an ejection module 23-1 that includes a piezoelectric element 60 and includes n ejection sections 600 that eject liquid in response to the driving of the piezoelectric element 60, an ejection module 23-2 that includes a piezoelectric element 60 and includes n ejection sections 600 that eject liquid in response to the driving of the piezoelectric element 60, an ejection module 23-3 that includes a piezoelectric element 60 and includes n ejection sections 600 that eject liquid in response to the driving of the piezoelectric element 60, an ejection module 23-4 that includes a piezoelectric element 60 and includes n ejection sections 600 that eject liquid in response to the driving of the piezoelectric element 60, an ejection module 23-5 that includes a piezoelectric element 60 and includes n ejection sections 600 that eject liquid in response to the driving of the piezoelectric element 60, and an ejection module 23-6 that includes a piezoelectric element 60 and includes n ejection sections 600 that eject liquid in response to the driving of the piezoelectric element 60. In other words, the liquid ejection module 20 ejects liquid in response to the driving of the piezoelectric element 60 possessed by the ejection module 23-1, ejects liquid in response to the driving of the piezoelectric element 60 possessed by the ejection module 23-2, ejects liquid in response to the driving of the piezoelectric element 60 possessed by the ejection module 23-3, ejects liquid in response to the driving of the piezoelectric element 60 possessed by the ejection module 23-4, ejects liquid in response to the driving of the piezoelectric element 60 possessed by the ejection module 23-5, and ejects liquid in response to the driving of the piezoelectric element 60 possessed by the ejection module 23-6.

[0119] 1.5 Head drive module structure Next, the structure of the head drive module 10 will be described with reference to Figure 12. Figure 12 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 are perpendicular to one another. In the following description, the starting point 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 point 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. The starting point 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.

[0120] 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.

[0121] The drive circuit board 800 includes a wiring board 810 on which the above-mentioned plurality of drive circuits 52 are provided, and outputs a drive signal COM to the liquid ejection module 20. 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 conduction member group 720 is located between the drive circuit board 800 and the heat sink 710, and by attaching the heat sink 710 to the wiring board 810, the heat conduction member group 720 comes into contact with both the plurality of drive circuits 52 provided on the wiring board 810 and the heat sink 710. As a result, the heat conduction member group 720 conducts heat generated by the plurality of drive circuits 52 provided on the wiring board 810 to the heat sink 710.

[0122] The structure of the head drive module 10 configured as above will now be described in detail with reference to the drawings.

[0123] First, a specific example of the structure of the drive circuit board 800 of the head drive module 10 will be described. Fig. 13 is a diagram showing an example of the cross-sectional structure of a wiring board 810 on which multiple drive circuits 52 are provided. As shown in Fig. 13, the wiring board 810 has a first layer 831, a second layer 832, a third layer 833, a fourth layer 834, a fifth layer 835, and multiple insulating layers 840. The first layer 831, second layer 832, third layer 833, fourth layer 834, and fifth layer 835 are positioned along the Z2 direction from the +Z2 side to the -Z2 side in the order of first layer 831, second layer 832, third layer 833, fourth layer 834, and fifth layer 835, and multiple insulating layers 840 are positioned along the Z2 direction between the first layer 831 and the second layer 832, between the second layer 832 and the third layer 833, between the third layer 833 and the fourth layer 834, and between the fourth layer 834 and the fifth layer 835.

[0124] The first layer 831 and the fifth layer 835 are provided with a plurality of electronic components that constitute various circuits, including a plurality of drive circuits 52. Furthermore, the first layer 831, the second layer 832, the third layer 833, the fourth layer 834, and the fifth layer 835 are provided with a plurality of wiring patterns that electrically connect the electronic components provided on the first layer 831 and the fifth layer 835 and transmit various signals. The plurality of wiring patterns formed on each of the first layer 831, the second layer 832, the third layer 833, the fourth layer 834, and the fifth layer 835 are made of a material with excellent electrical conductivity, and are formed, for example, by etching copper foil. Furthermore, the insulating layer 840 functions as an insulator layer that insulates the plurality of wiring patterns formed on the first layer 831, the second layer 832, the third layer 833, the fourth layer 834, and the fifth layer 835 from one another. Such insulating layer 840 may be made of, for example, epoxy glass formed by impregnating glass fiber cloth with epoxy resin.

[0125] That is, wiring board 810 in the first embodiment is a multilayer board including a first layer 831, a second layer 832, a third layer 833, a fourth layer 834, and a fifth layer 835, where first layer 831 and fifth layer 835 constitute surface layers of wiring board 810, and second layer 832, third layer 833, and fourth layer 834 constitute inner layers of wiring board 810. Note that wiring board 810 may have through holes (not shown) that penetrate insulating layer 840 along the Z2 direction and electrically connect first layer 831, second layer 832, third layer 833, fourth layer 834, and fifth layer 835 to one another. In addition, in the following explanation, it is assumed that the electronic components constituting the various circuits including the multiple drive circuits 52 possessed by the drive circuit board 800 are provided on the first layer 831, but some of the electronic components constituting the various circuits including the multiple drive circuits 52 possessed by the drive circuit board 800 may be provided on the fifth layer 835.

[0126] The detailed configurations of the first layer 831, the second layer 832, the third layer 833, and the fourth layer 834 will be described with reference to Figures 14 to 17. Figure 14 is a diagram showing an example of the configuration of the first layer 831 when the wiring board 810 is viewed from the Z2 side along the Z2 direction.

[0127] 14, wiring board 810 is a substantially rectangular multilayer board 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.

[0128] On a first layer 831 of the wiring board 810, connection parts CN1 and CN2, an integrated circuit 101, and a plurality of drive circuits 52 are provided.

[0129] 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.

[0130] The connection unit CN2 is located along a side 812 of the wiring board 810, and is electrically connected to the liquid discharging module 20. Specifically, one end of a wiring member 30 is attached to the connection unit CN2. The other end of the wiring member 30 is connected to a connection unit 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 from the connection unit 330 to the liquid discharging module 20 via the connection unit CN2 and the wiring member 30. That is, the connection unit CN2 is provided on the wiring board 810, and electrically connects the wiring board 810 and the liquid discharging module 20, thereby transmitting the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 to the liquid discharging module 20. Here, the connection portions CN2, 330 may be BtoB connectors that allow mutual electrical connection without using a cable or the like. In this case, the connection portions CN2, 330 form the wiring member 30.

[0131] The integrated circuit 101 is located on the -X2 side of the connection part CN1. The integrated circuit 101 constitutes part or all of the control circuit 100 described above. That is, an image information signal IP is input to the integrated circuit 101 via the connection part CN1. The integrated circuit 101 then generates and outputs various signals based on the input image information signal IP. Here, the integrated circuit 101 may include part or all of the conversion circuit 120 in addition to the control circuit 100. Note that, in the liquid ejection device 1 of the first embodiment, the integrated circuit 101 will be described as including the entire control circuit 100 and the entire conversion circuit 120, but part of the control circuit 100 or part of the conversion circuit 120 may be configured outside the integrated circuit 101.

[0132] FIG. 14 illustrates an example in which the integrated circuit 101 is disposed on the first layer 831 of the wiring substrate 810 together with the plurality of drive circuits 52. However, the integrated circuit 101 may be disposed on a substrate (not shown) different from the wiring substrate 810. When the integrated circuit 101 and the plurality of drive circuits 52 are mounted on a common substrate as shown in FIG. 14, the wiring pattern through which signals are transmitted between the plurality of drive circuits 52 and the integrated circuit 101 can be shortened. This reduces the risk of noise and other interference being superimposed on signals transmitted between the plurality of drive circuits 52 and the integrated circuit 101. However, the plurality of drive circuits 52 generate more heat than the integrated circuit 101. Therefore, if the heat generated by the plurality of drive circuits 52 contributes to the integrated circuit 101, the stability of the operation of the integrated circuit 101 may be reduced. To address this issue, mounting the integrated circuit 101 on a substrate different from that of the plurality of drive circuits 52 reduces the risk of the heat generated by the plurality of drive circuits 52 contributing to the integrated circuit 101.

[0133] The multiple drive circuits 52 are located between the integrated circuit 101 and the connection part CN2, and are arranged side by side along the X2 direction. Specifically, the multiple drive circuits 52, that is, drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6, are provided on a first layer 831 of the wiring board 810, and are arranged side by side on the first layer 831 of the wiring board 810 from the −X2 side to the +X2 side along the X2 direction in the order of drive circuits 52a1, 52b1, 52a2, 52b2, 52a3, 52b3, 52a4, 52b4, 52a5, 52b5, 52a6, 52b6, 52c1, 52c2, 52c3, 52c4, 52c5, and 52c6.

[0134] In this case, the transistor M1 and the transistor M2 included in each of the multiple drive circuits 52 are positioned side by side along 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 along the X2 direction, and the integrated circuit 500 is positioned on the +Y2 side of the transistors M1 and M2 positioned side by side along 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 on the first layer 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.

[0135] 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, the first layer 831 of the wiring board 810 is configured with a row of integrated circuits 500 positioned side by side from the side 812 to the side 811, a row of transistors M1 and M2 positioned side by side from the side 812 to the side 811, and a row of inductors L1 positioned side by side from the side 812 to the side 811.

[0136] In the first layer 831 of the wiring board 810 of the liquid ejection device 1 of the first embodiment, the drive circuits 52a1, 52a2, 52b1, 52b2, 52c1, and 52c2 are positioned such that the drive circuit 52a2 is located between the drive circuits 52a1 and 52c1 along the X2 direction, and the shortest distance between the drive circuits 52c2 and 52c1 is shorter than the shortest distance between the drive circuits 52c2 and 52a2, and the drive circuits 52b1 and 52b2 are located between the drive circuits 52a1 and 52c1 and between the drive circuits 52a1 and 52c2 along the X2 direction.

[0137] Similarly, in the first layer 831 of the wiring board 810 of the liquid ejection device 1 of the first embodiment, the drive circuits 52a3, 52a4, 52b3, 52b4, 52c3, and 52c4 are positioned such that the drive circuit 52a4 is located between the drive circuits 52a3 and 52c3 along the X2 direction, and the shortest distance between the drive circuits 52c4 and 52c3 is shorter than the shortest distance between the drive circuits 52c4 and 52a4, and the drive circuits 52b3 and 52b4 are located between the drive circuits 52a3 and 52c3 along the X2 direction, and are also located between the drive circuits 52a3 and 52c4.

[0138] Similarly, in the first layer 831 of the wiring board 810 of the liquid ejection device 1 of the first embodiment, the drive circuits 52a5, 52a6, 52b5, 52b6, 52c5, and 52c6 are positioned such that the drive circuit 52a6 is located between the drive circuits 52a5 and 52c5 along the X2 direction, and the shortest distance between the drive circuits 52c6 and 52c5 is shorter than the shortest distance between the drive circuits 52c6 and 52a6, and the drive circuits 52b5 and 52b6 are located between the drive circuits 52a5 and 52c5 along the X2 direction, and are also located between the drive circuits 52a5 and 52c6.

[0139] In this case, the drive circuit 52a1 that outputs the drive signal COMA1 to the piezoelectric element 60 of the discharge module 23-1 and the drive circuit 52b1 that outputs the drive signal COMB1 are positioned adjacent to each other along the X2 direction, the drive circuit 52a2 that outputs the drive signal COMA2 to the piezoelectric element 60 of the discharge module 23-2 and the drive circuit 52b2 that outputs the drive signal COMB2 are positioned adjacent to each other along the X2 direction, and the drive circuit 52a3 that outputs the drive signal COMA3 to the piezoelectric element 60 of the discharge module 23-3 and the drive circuit 52b3 that outputs the drive signal COMB3 are positioned adjacent to each other along the X2 direction. The drive circuit 52a4 that outputs the drive signal COMA4 to the piezoelectric element 60 of the discharge module 23-4 and the drive circuit 52b4 that outputs the drive signal COMB4 are positioned adjacent to each other along the X2 direction, the drive circuit 52a5 that outputs the drive signal COMA5 to the piezoelectric element 60 of the discharge module 23-5 and the drive circuit 52b5 that outputs the drive signal COMB5 are positioned adjacent to each other along the X2 direction, and the drive circuit 52a6 that outputs the drive signal COMA6 to the piezoelectric element 60 of the discharge module 23-6 and the drive circuit 52b6 that outputs the drive signal COMB6 are positioned adjacent to each other along the X2 direction.

[0140] In detail, the drive circuit 52a1 outputs a drive signal COMA1 for driving the piezoelectric element 60 of the ejection module 23-1 so that ink is ejected from the ejection section 600 of the ejection module 23-1, and the drive circuit 52b1 outputs a drive signal COMB1 for driving the piezoelectric element 60 of the ejection module 23-1 so that ink is ejected from the ejection section 600 of the ejection module 23-1. These are positioned adjacent to each other along the X2 direction on the first layer 831 of the wiring board 810, with the drive circuit 52a1 on the -X2 side and the drive circuit 52b1 on the +X2 side.

[0141] The drive circuit 52a2 outputs a drive signal COMA2 for driving the piezoelectric element 60 of the ejection module 23-2 so that ink is ejected from the ejection section 600 of the ejection module 23-2, and the drive circuit 52b2 outputs a drive signal COMB2 for driving the piezoelectric element 60 of the ejection module 23-2 so that ink is ejected from the ejection section 600 of the ejection module 23-2. These circuits are positioned adjacent to each other along the X2 direction on the first layer 831 of the wiring board 810, on the +X2 side of the drive circuit 52b1, with the drive circuit 52a2 on the -X2 side and the drive circuit 52b2 on the +X2 side.

[0142] The drive circuit 52a3 outputs a drive signal COMA3 for driving the piezoelectric element 60 of the ejection module 23-3 so that ink is ejected from the ejection section 600 of the ejection module 23-3, and the drive circuit 52b3 outputs a drive signal COMB3 for driving the piezoelectric element 60 of the ejection module 23-3 so that ink is ejected from the ejection section 600 of the ejection module 23-3. These are positioned adjacent to each other along the X2 direction on the first layer 831 of the wiring board 810, on the +X2 side of the drive circuit 52b2, with the drive circuit 52a3 on the -X2 side and the drive circuit 52b3 on the +X2 side.

[0143] The drive circuit 52a4 outputs a drive signal COMA4 for driving the piezoelectric element 60 of the ejection module 23-4 so that ink is ejected from the ejection section 600 of the ejection module 23-4, and the drive circuit 52b4 outputs a drive signal COMB4 for driving the piezoelectric element 60 of the ejection module 23-4 so that ink is ejected from the ejection section 600 of the ejection module 23-4. These are positioned adjacent to each other along the X2 direction on the first layer 831 of the wiring board 810, on the +X2 side of the drive circuit 52b3, with the drive circuit 52a4 on the -X2 side and the drive circuit 52b4 on the +X2 side.

[0144] The drive circuit 52a5 outputs a drive signal COMA5 for driving the piezoelectric element 60 of the ejection module 23-5 so that ink is ejected from the ejection section 600 of the ejection module 23-5, and the drive circuit 52b5 outputs a drive signal COMB5 for driving the piezoelectric element 60 of the ejection module 23-5 so that ink is ejected from the ejection section 600 of the ejection module 23-5. These are positioned adjacent to each other along the X2 direction on the first layer 831 of the wiring board 810, on the +X2 side of the drive circuit 52b4, with the drive circuit 52a5 on the -X2 side and the drive circuit 52b5 on the +X2 side.

[0145] The drive circuit 52a6 outputs a drive signal COMA6 for driving the piezoelectric element 60 of the ejection module 23-6 so that ink is ejected from the ejection section 600 of the ejection module 23-6, and the drive circuit 52b6 outputs a drive signal COMB6 for driving the piezoelectric element 60 of the ejection module 23-6 so that ink is ejected from the ejection section 600 of the ejection module 23-6. These drive circuits are located adjacent to each other along the X2 direction on the first layer 831 of the wiring board 810, on the +X2 side of the drive circuit 52b5, with the drive circuit 52a6 on the -X2 side and the drive circuit 52b6 on the +X2 side.

[0146] Furthermore, the drive circuit 52c1 that outputs the drive signal COMC1 for driving the piezoelectric element 60 of the discharge module 23-1 so that ink is not discharged from the discharge unit 600 of the discharge module 23-1 is located on the +X2 side of the drive circuit 52b6 along the X2 direction on the first layer 831 of the wiring substrate 810. The drive circuit 52c2 that outputs the drive signal COMC2 for driving the piezoelectric element 60 of the discharge module 23-2 so that ink is not discharged from the discharge unit 600 of the discharge module 23-2 is located on the +X2 side of the drive circuit 52c1 along the X2 direction on the first layer 831 of the wiring substrate 810. The drive circuit 52c3 outputs a drive signal COMC3 for driving the piezoelectric element 60 of the discharge module 23-3 so that the discharge unit 600 of the discharge module 23-3 does not discharge ink, and is located on the +X2 side of the drive circuit 52c2 along the X2 direction on the first layer 831 of the wiring substrate 810. The drive circuit 52c4 outputs a drive signal COMC4 for driving the piezoelectric element 60 of the discharge module 23-4 so that the discharge unit 600 of the discharge module 23-4 does not discharge ink, and is located on the +X2 side of the drive circuit 52c3 along the X2 direction on the first layer 831 of the wiring substrate 810. The drive circuit 52c5 outputs a drive signal COMC5 for driving the piezoelectric element 60 of the discharge module 23-5 so that the discharge unit 600 of the discharge module 23-5 does not discharge ink, and is located on the +X2 side of the drive circuit 52c4 along the X2 direction on the first layer 831 of the wiring substrate 810. The drive circuit 52c6 outputs a drive signal COMC6 for driving the piezoelectric element 60 of the ejection module 23-6 so that ink is not ejected from the ejection section 600 of the ejection module 23-6, and is located on the +X2 side of the drive circuit 52c5 along the X2 direction on the first layer 831 of the wiring substrate 810.

[0147] That is, in the head driving module 10, the driving circuits 52a1 to 52a6, 52b1 to 52b6 that output driving signals COMA1 to COMA6, COMB1 to COMB6 that drive the piezoelectric elements 60 to eject ink are positioned adjacent to each other for each corresponding ejection module 23 along the X2 direction on the first layer 831 of the wiring board 810, and the driving circuits 52c1 to 52c6 that output driving signals COMC1 to COMC6 that drive the piezoelectric elements 60 so as not to eject ink are positioned along the X2 direction on the first layer 831 of the wiring board 810 on the +X2 side of the driving circuits 52a1 to 52a6, 52b1 to 52b6 in the order of driving circuits 52c1, 52c2, 52c3, 52c4, 52c5, 52c6.

[0148] In the drive circuit board 800 configured as described above, an image information signal IP input via the connection part CN1 is supplied to the integrated circuit 101. Then, the integrated circuit 101 generates and outputs basic drive signals dA1 to dA6, dB1 to dB6, dC1 to dC6 and a data signal DATA based on the input image information signal IP. The basic drive signals dA1 to dA6, dB1 to dB6, dC1 to dC6 output by the integrated circuit 101 propagate through a wiring pattern (not shown) of the wiring board 810 and are input to the corresponding drive circuits 52. The multiple drive circuits 52 generate and output drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 based on the input basic drive signals dA1 to dA6, dB1 to dB6, dC1 to dC6. Then, a plurality of signals including drive signals COMA1 to COMA6, COMB1 to COMB6, COMC1 to COMC6 output by each of the plurality of drive circuits 52 and a signal based on the data signal DATA output by the integrated circuit 101 are supplied to the liquid ejection module 20 via the connection part CN2.

[0149] As described above, of the signals supplied from the head driving module 10 to the liquid ejection module 20, the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 output by each of the multiple drive circuits 52 are analog signals that are supplied to the corresponding piezoelectric elements 60 and drive the piezoelectric elements 60, as described above. If waveform distortion occurs in such drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6, this directly contributes to the ink ejection status from the corresponding ejection section 600. In other words, from the perspective of improving the ejection accuracy of ink ejected from the liquid ejection module 20, reducing the risk of waveform distortion occurring in the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 is an important factor in improving the ejection accuracy of ink ejected from the liquid ejection module 20.

[0150] An example of the configuration of a wiring pattern through which the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 output by the drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6, respectively, propagate in the head drive module 10 will be described with reference to FIGS.

[0151] 15 is a diagram showing an example of a wiring pattern provided on a second layer 832 of the wiring substrate 810, Fig. 16 is a diagram showing an example of a wiring pattern provided on a third layer 833 of the wiring substrate 810, and Fig. 17 is a diagram showing an example of a wiring pattern provided on a fourth layer 834 of the wiring substrate 810. Here, in the head driving module 10 of the first embodiment, a description will be given assuming that a plurality of wiring patterns through which drive signals COMA1 to COMA6 propagate are provided on the second layer 832 of the wiring substrate 810, a plurality of wiring patterns through which drive signals COMB1 to COMB6 propagate are provided on the third layer 833 of the wiring substrate 810, and a plurality of wiring patterns through which drive signals COMC1 to COMC6 propagate are provided on the fourth layer 834 of the wiring substrate 810. 15 to 17 are perspective views of the wiring board 810 viewed from the +Z2 side to the -Z2 side along the Z2 direction, and in FIGS. 15 to 17, the multiple driving circuits 52, connection parts CN1 and CN2, and integrated circuit 101 provided on the first layer 831 of the wiring board 810 are shown by dashed lines.

[0152] As shown in FIG. 14, the drive circuit 52a1 that outputs the drive signal COMA1 is located on the +X2 side of the connection portion CN2 on the first layer 831. As shown in FIG. 15, one end of the inductor L1, to which the drive circuit 52a1 outputs the drive signal COMA1, is electrically connected to one end of a wiring WA1 provided on the second layer 832 via a through-hole (not shown). The wiring WA1 extends along the X2 direction on the second layer 832. The other end of the wiring WA1 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes the wiring WA1 that electrically connects the drive circuit 52a1 and the connection portion CN2 and propagates the drive signal COMA1. As a result, the drive signal COMA1 output by the drive circuit 52a1 is propagated to the connection portion CN2.

[0153] As shown in FIG. 14, the drive circuit 52b1 that outputs the drive signal COMB1 is located on the +X2 side of the drive circuit 52a1 on the first layer 831. As shown in FIG. 16, one end of the inductor L1, to which the drive circuit 52b1 outputs the drive signal COMB1, is electrically connected to one end of a wiring WB1 provided on the third layer 833 via a through-hole (not shown). The wiring WB1 extends along the X2 direction on the third layer 833. The other end of the wiring WB1 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WB1 that electrically connects the drive circuit 52b1 and the connection portion CN2 and propagates the drive signal COMB1. As a result, the drive signal COMB1 output by the drive circuit 52b1 is propagated to the connection portion CN2.

[0154] As shown in FIG. 14, the drive circuit 52a2 that outputs the drive signal COMA2 is located on the +X2 side of the drive circuit 52b1 on the first layer 831. As shown in FIG. 15, one end of the inductor L1, to which the drive circuit 52a2 outputs the drive signal COMA2, is electrically connected to one end of a wiring WA2 provided on the second layer 832 via a through-hole (not shown). The wiring WA2 extends along the X2 direction on the second layer 832. The other end of the wiring WA2 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WA2 that electrically connects the drive circuit 52a2 and the connection portion CN2 and propagates the drive signal COMA2. This allows the drive signal COMA2 output by the drive circuit 52a2 to propagate to the connection portion CN2.

[0155] As shown in FIG. 14, the drive circuit 52b2 that outputs the drive signal COMB2 is located on the +X2 side of the drive circuit 52a2 on the first layer 831. As shown in FIG. 16, one end of the inductor L1, to which the drive circuit 52b2 outputs the drive signal COMB2, is electrically connected to one end of a wiring WB2 provided on the third layer 833 via a through-hole (not shown). The wiring WB2 extends along the X2 direction on the third layer 833. The other end of the wiring WB2 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WB2 that electrically connects the drive circuit 52b2 and the connection portion CN2 and propagates the drive signal COMB2. As a result, the drive signal COMB2 output by the drive circuit 52b2 is propagated to the connection portion CN2.

[0156] As shown in FIG. 14, the drive circuit 52a3, which outputs the drive signal COMA3, is located on the +X2 side of the drive circuit 52b2 on the first layer 831. As shown in FIG. 15, one end of the inductor L1, to which the drive circuit 52a3 outputs the drive signal COMA3, is electrically connected to one end of a wiring WA3 provided on the second layer 832 via a through-hole (not shown). The wiring WA3 extends along the X2 direction on the second layer 832. The other end of the wiring WA3 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes the wiring WA3 that electrically connects the drive circuit 52a3 and the connection portion CN2 and propagates the drive signal COMA3. As a result, the drive signal COMA3 output by the drive circuit 52a3 is propagated to the connection portion CN2.

[0157] As shown in FIG. 14, the drive circuit 52b3, which outputs the drive signal COMB3, is located on the +X2 side of the drive circuit 52a3 on the first layer 831. As shown in FIG. 16, one end of the inductor L1, to which the drive circuit 52b3 outputs the drive signal COMB3, is electrically connected to one end of a wiring WB3 provided on the third layer 833 via a through-hole (not shown). The wiring WB3 extends along the X2 direction on the third layer 833. The other end of the wiring WB3 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WB3 that electrically connects the drive circuit 52b3 and the connection portion CN2 and propagates the drive signal COMB3. As a result, the drive signal COMB3 output by the drive circuit 52b3 is propagated to the connection portion CN2.

[0158] As shown in FIG. 14, the drive circuit 52a4, which outputs the drive signal COMA4, is located on the +X2 side of the drive circuit 52b3 on the first layer 831. As shown in FIG. 15, one end of the inductor L1, to which the drive circuit 52a4 outputs the drive signal COMA4, is electrically connected to one end of a wiring WA4 provided on the second layer 832 via a through-hole (not shown). The wiring WA4 extends along the X2 direction on the second layer 832. The other end of the wiring WA4 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WA4 that electrically connects the drive circuit 52a4 and the connection portion CN2 and propagates the drive signal COMA4. This allows the drive signal COMA4 output by the drive circuit 52a4 to propagate to the connection portion CN2.

[0159] As shown in FIG. 14, the drive circuit 52b4, which outputs the drive signal COMB4, is located on the +X2 side of the drive circuit 52a4 on the first layer 831. As shown in FIG. 16, one end of the inductor L1, to which the drive circuit 52b4 outputs the drive signal COMB4, is electrically connected to one end of a wiring WB4 provided on the third layer 833 via a through-hole (not shown). The wiring WB4 extends along the X2 direction on the third layer 833. The other end of the wiring WB4 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WB4 that electrically connects the drive circuit 52b4 and the connection portion CN2 and propagates the drive signal COMB4. This allows the drive signal COMB4 output by the drive circuit 52b4 to propagate to the connection portion CN2.

[0160] As shown in FIG. 14, the drive circuit 52a5, which outputs the drive signal COMA5, is located on the +X2 side of the drive circuit 52b4 on the first layer 831. As shown in FIG. 15, one end of the inductor L1, to which the drive circuit 52a5 outputs the drive signal COMA5, is electrically connected to one end of a wiring WA5 provided on the second layer 832 via a through-hole (not shown). The wiring WA5 extends along the X2 direction on the second layer 832. The other end of the wiring WA5 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WA5 that electrically connects the drive circuit 52a5 and the connection portion CN2 and propagates the drive signal COMA5. As a result, the drive signal COMA5 output by the drive circuit 52a5 is propagated to the connection portion CN2.

[0161] As shown in FIG. 14, the drive circuit 52b5, which outputs the drive signal COMB5, is located on the +X2 side of the drive circuit 52a5 on the first layer 831. As shown in FIG. 16, one end of the inductor L1, to which the drive circuit 52b5 outputs the drive signal COMB5, is electrically connected to one end of a wiring WB5 provided on the third layer 833 via a through-hole (not shown). The wiring WB5 extends along the X2 direction on the third layer 833. The other end of the wiring WB5 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WB5 that electrically connects the drive circuit 52b5 and the connection portion CN2 and propagates the drive signal COMB5. As a result, the drive signal COMB5 output by the drive circuit 52b5 is propagated to the connection portion CN2.

[0162] 14, the drive circuit 52a6 that outputs the drive signal COMA6 is located on the +X2 side of the drive circuit 52b5 on the first layer 831. Then, as shown in Fig. 15, one end of the inductor L1 to which the drive circuit 52a6 outputs the drive signal COMA6 is electrically connected, via a through-hole (not shown), to one end of a wire WA6 provided on the second layer 832. The wire WA6 extends along the X2 direction on the second layer 832.

[0163] The other end of the wiring WA6 is electrically connected to the connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes the wiring WA6 that electrically connects the drive circuit 52a6 and the connection portion CN2 and propagates the drive signal COMA6. As a result, the drive signal COMA6 output by the drive circuit 52a6 is propagated to the connection portion CN2.

[0164] As shown in FIG. 14, the drive circuit 52b6, which outputs the drive signal COMB6, is located on the +X2 side of the drive circuit 52a6 on the first layer 831. As shown in FIG. 16, one end of the inductor L1, to which the drive circuit 52b6 outputs the drive signal COMB6, is electrically connected to one end of a wiring WB6 provided on the third layer 833 via a through-hole (not shown). The wiring WB6 extends along the X2 direction on the third layer 833. The other end of the wiring WB6 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WB6 that electrically connects the drive circuit 52b6 and the connection portion CN2 and propagates the drive signal COMB6. As a result, the drive signal COMB6 output by the drive circuit 52b6 is propagated to the connection portion CN2.

[0165] As shown in FIG. 14, the drive circuit 52c1 that outputs the drive signal COMC1 is located on the +X2 side of the drive circuit 52b6 on the first layer 831. As shown in FIG. 17, one end of the inductor L1, to which the drive circuit 52c1 outputs the drive signal COMC1, is electrically connected to one end of a wiring WC1 provided on the fourth layer 834 via a through-hole (not shown). The wiring WC1 extends along the X2 direction on the fourth layer 834. The other end of the wiring WC1 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WC1 that electrically connects the drive circuit 52c1 and the connection portion CN2 and propagates the drive signal COMC1. This allows the drive signal COMC1 output by the drive circuit 52c1 to propagate to the connection portion CN2.

[0166] As shown in FIG. 14, the drive circuit 52c2 that outputs the drive signal COMC2 is located on the +X2 side of the drive circuit 52c1 on the first layer 831. As shown in FIG. 17, one end of the inductor L1, to which the drive circuit 52c2 outputs the drive signal COMC2, is electrically connected to one end of a wiring WC2 provided on the fourth layer 834 via a through-hole (not shown). The wiring WC2 extends along the X2 direction on the fourth layer 834. The other end of the wiring WC2 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WC2 that electrically connects the drive circuit 52c2 and the connection portion CN2 and propagates the drive signal COMC2. This allows the drive signal COMC2 output by the drive circuit 52c2 to propagate to the connection portion CN2.

[0167] As shown in FIG. 14, the drive circuit 52c3, which outputs the drive signal COMC3, is located on the +X2 side of the drive circuit 52c2 on the first layer 831. As shown in FIG. 17, one end of the inductor L1, to which the drive circuit 52c3 outputs the drive signal COMC3, is electrically connected to one end of a wiring WC3 provided on the fourth layer 834 via a through-hole (not shown). The wiring WC3 extends along the X2 direction on the fourth layer 834. The other end of the wiring WC3 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WC3 that electrically connects the drive circuit 52c3 and the connection portion CN2 and propagates the drive signal COMC3. This allows the drive signal COMC3 output by the drive circuit 52c3 to propagate to the connection portion CN2.

[0168] As shown in FIG. 14, the drive circuit 52c4, which outputs the drive signal COMC4, is located on the +X2 side of the drive circuit 52c3 on the first layer 831. As shown in FIG. 17, one end of the inductor L1, to which the drive circuit 52c4 outputs the drive signal COMC4, is electrically connected to one end of a wiring WC4 provided on the fourth layer 834 via a through-hole (not shown). The wiring WC4 extends along the X2 direction on the fourth layer 834. The other end of the wiring WC4 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WC4 that electrically connects the drive circuit 52c4 and the connection portion CN2 and propagates the drive signal COMC4. This allows the drive signal COMC4 output by the drive circuit 52c4 to propagate to the connection portion CN2.

[0169] As shown in FIG. 14, the drive circuit 52c5, which outputs the drive signal COMC5, is located on the +X2 side of the drive circuit 52c4 on the first layer 831. As shown in FIG. 17, one end of the inductor L1, to which the drive circuit 52c5 outputs the drive signal COMC5, is electrically connected to one end of a wiring WC5 provided on the fourth layer 834 via a through-hole (not shown). The wiring WC5 extends along the X2 direction on the fourth layer 834. The other end of the wiring WC5 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring substrate 810 includes a wiring WC5 that electrically connects the drive circuit 52c5 and the connection portion CN2 and propagates the drive signal COMC5. As a result, the drive signal COMC5 output by the drive circuit 52c5 is propagated to the connection portion CN2.

[0170] As shown in FIG. 14, the drive circuit 52c6 that outputs the drive signal COMC6 is located on the +X2 side of the drive circuit 52c5 on the first layer 831. As shown in FIG. 17, one end of the inductor L1, to which the drive circuit 52c6 outputs the drive signal COMC6, is electrically connected to one end of a wiring WC6 provided on the fourth layer 834 via a through-hole (not shown). The wiring WC6 extends along the X2 direction on the fourth layer 834. The other end of the wiring WC6 is electrically connected to a connection portion CN2 provided on the first layer 831 via a through-hole (not shown). That is, the wiring board 810 includes a wiring WC6 that electrically connects the drive circuit 52c6 and the connection portion CN2 and propagates the drive signal COMC6. As a result, the drive signal COMC6 output by the drive circuit 52c6 is propagated to the connection portion CN2.

[0171] As described above, in the liquid ejection device 1 of the first embodiment, the drive circuit board 800 of the head drive module 10 includes drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 as a plurality of drive circuits 52, and the wiring board 810 of the drive circuit board 800 includes wires WA1 to WA6, WB1 to WB6, and WC1 to WC6 as a plurality of wiring patterns that electrically connect each of the plurality of drive circuits 52 to the connection portion CN2. The driving circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 are arranged on the wiring substrate 810 along the X2 direction from the +X2 side to the −X2 side in the order of driving circuits 52a1, 52b1, 52a2, 52b2, 52a3, 52b3, 52a4, 52b4, 52a5, 52b5, 52a6, 52b6, 52c1, 52c2, 52c3, 52c4, 52c5, and 52c6.

[0172] That is, the drive circuits 52a1, 52b1, and 52c1 that output drive signals COMA1, COMB1, and COMC1 to the piezoelectric element 60 of the discharge module 23-1 are located on the first layer 831 of the wiring substrate 810 in the order of drive circuit 52a1, drive circuit 52b1, and drive circuit 52c1 along the X2 direction from the side 812 on which the connection portion CN2 is located toward the side 811 on which the connection portion CN1 is located. Therefore, the length of the wiring WA1 electrically connecting the drive circuit 52a1 and the connection portion CN2 is shorter than the lengths of the wiring WB1 electrically connecting the drive circuit 52b1 and the connection portion CN2 and the wiring WC1 electrically connecting the drive circuit 52c1 and the connection portion CN2, and the length of the wiring WB1 electrically connecting the drive circuit 52b1 and the connection portion CN2 is shorter than the length of the wiring WC1 electrically connecting the drive circuit 52c1 and the connection portion CN2. That is, the wiring WB1 is longer than the wiring WA1 and shorter than the wiring WC1.

[0173] Furthermore, the drive circuits 52a2, 52b2, and 52c2 that output drive signals COMA2, COMB2, and COMC2 to the piezoelectric element 60 of the discharge module 23-2 are located on the first layer 831 of the wiring substrate 810 in the order of drive circuit 52a2, drive circuit 52b2, and drive circuit 52c2 along the X2 direction from the side 812 on which the connection portion CN2 is located toward the side 811 on which the connection portion CN1 is located. Therefore, the length of the wiring WA2 electrically connecting the drive circuit 52a2 to the connection portion CN2 is shorter than the lengths of the wiring WB2 electrically connecting the drive circuit 52b2 to the connection portion CN2 and the wiring WC2 electrically connecting the drive circuit 52c2 to the connection portion CN2, and the length of the wiring WB2 electrically connecting the drive circuit 52b2 to the connection portion CN2 is shorter than the length of the wiring WC2 electrically connecting the drive circuit 52c2 to the connection portion CN2. That is, the wiring WB2 is longer than the wiring WA2 and shorter than the wiring WC2.

[0174] Furthermore, the drive circuits 52a3, 52b3, and 52c3 that output drive signals COMA3, COMB3, and COMC3 to the piezoelectric element 60 of the discharge module 23-3 are located on the first layer 831 of the wiring substrate 810 in the order of drive circuit 52a3, drive circuit 52b3, and drive circuit 52c3 along the X2 direction from the side 812 on which the connection portion CN2 is located toward the side 811 on which the connection portion CN1 is located. Therefore, the length of the wiring WA3 electrically connecting the drive circuit 52a3 to the connection portion CN2 is shorter than the lengths of the wiring WB3 electrically connecting the drive circuit 52b3 to the connection portion CN2 and the wiring WC3 electrically connecting the drive circuit 52c3 to the connection portion CN2, and the length of the wiring WB3 electrically connecting the drive circuit 52b3 to the connection portion CN2 is shorter than the length of the wiring WC3 electrically connecting the drive circuit 52c3 to the connection portion CN2. In other words, the wiring WB3 is longer than the wiring WA3 and shorter than the wiring WC3.

[0175] Furthermore, the drive circuits 52a4, 52b4, and 52c4 that output drive signals COMA4, COMB4, and COMC4 to the piezoelectric element 60 of the discharge module 23-4 are located on the first layer 831 of the wiring substrate 810 in the order of drive circuit 52a4, drive circuit 52b4, and drive circuit 52c4 along the X2 direction from the side 812 on which the connection portion CN2 is located toward the side 811 on which the connection portion CN1 is located. Therefore, the length of the wiring WA4 electrically connecting the drive circuit 52a4 and the connection portion CN2 is shorter than the lengths of the wiring WB4 electrically connecting the drive circuit 52b4 and the connection portion CN2 and the wiring WC4 electrically connecting the drive circuit 52c4 and the connection portion CN2, and the length of the wiring WB4 electrically connecting the drive circuit 52b4 and the connection portion CN2 is shorter than the length of the wiring WC4 electrically connecting the drive circuit 52c4 and the connection portion CN2. In other words, the wiring WB4 is longer than the wiring WA4 and shorter than the wiring WC4.

[0176] Furthermore, the drive circuits 52a5, 52b5, and 52c5 that output drive signals COMA5, COMB5, and COMC5 to the piezoelectric element 60 of the discharge module 23-5 are located on the first layer 831 of the wiring substrate 810 in the order of drive circuit 52a5, drive circuit 52b5, and drive circuit 52c5 along the X2 direction from the side 812 on which the connection portion CN2 is located toward the side 811 on which the connection portion CN1 is located. Therefore, the length of the wiring WA5 electrically connecting the drive circuit 52a5 and the connection portion CN2 is shorter than the lengths of the wiring WB5 electrically connecting the drive circuit 52b5 and the connection portion CN2 and the wiring WC5 electrically connecting the drive circuit 52c5 and the connection portion CN2, and the length of the wiring WB5 electrically connecting the drive circuit 52b5 and the connection portion CN2 is shorter than the length of the wiring WC5 electrically connecting the drive circuit 52c5 and the connection portion CN2. In other words, the wiring WB5 is longer than the wiring WA5 and shorter than the wiring WC5.

[0177] Furthermore, the drive circuits 52a6, 52b6, and 52c6 that output drive signals COMA6, COMB6, and COMC6 to the piezoelectric element 60 of the discharge module 23-6 are located on the first layer 831 of the wiring substrate 810 in the order of drive circuit 52a6, drive circuit 52b6, and drive circuit 52c6 along the X2 direction from the side 812 on which the connection portion CN2 is located toward the side 811 on which the connection portion CN1 is located. Therefore, the length of the wiring WA6 electrically connecting the drive circuit 52a6 to the connection portion CN2 is shorter than the lengths of the wiring WB6 electrically connecting the drive circuit 52b6 to the connection portion CN2 and the wiring WC6 electrically connecting the drive circuit 52c6 to the connection portion CN2, and the length of the wiring WB6 electrically connecting the drive circuit 52b6 to the connection portion CN2 is shorter than the length of the wiring WC6 electrically connecting the drive circuit 52c6 to the connection portion CN2. In other words, the wiring WB6 is longer than the wiring WA6 and shorter than the wiring WC6.

[0178] 14, in the liquid ejection device 1 of the first embodiment, on a first layer 831 of a wiring substrate 810, from a side 812 where the connection portion CN2 is located to a side 811 where the connection portion CN1 is located, there are drive circuits 52a1 and 52b1 that output drive signals COMA1 and COMB1 to drive corresponding piezoelectric elements 60 so that ink is ejected from the ejection portion 600 of the ejection module 23-1, drive circuits 52a2 and 52b2 that output drive signals COMA2 and COMB2 to drive corresponding piezoelectric elements 60 so that ink is ejected from the ejection portion 600 of the ejection module 23-2, drive circuits 52a3 and 52b3 that output drive signals COMA3 and COMB3 to drive corresponding piezoelectric elements 60 so that ink is ejected from the ejection portion 600 of the ejection module 23-3, and drive circuits 52a4 and 52b4 that output drive signals COMA5 and COMB6 to drive corresponding piezoelectric elements 60 so that ink is ejected from the ejection portion 600 of the ejection module 23-4. Drive circuits 52a4 and 52b4 outputting COMA4 and COMB4, drive circuits 52a5 and 52b5 outputting drive signals COMA5 and COMB5 that drive corresponding piezoelectric elements 60 so that ink is ejected from the ejection section 600 that the ejection module 23-5 has, and drive circuits 52a6 and 52b6 outputting drive signals COMA6 and COMB6 that drive corresponding piezoelectric elements 60 so that ink is ejected from the ejection section 600 that the ejection module 23-6 has. Drive circuits 52c1 to 52c6 that output drive signals COMC1 to COMC6 that drive corresponding piezoelectric elements 60 so as not to eject ink are arranged in this order on the drive circuits 52a1 to 52a6, 52b1 to 52b6+X2 side of the first layer 831 of the wiring board 810, from side 812 where connection part CN2 is located to side 811 where connection part CN1 is located.

[0179] That is, the drive circuit 52a1 that outputs the drive signal COMA1 that drives the corresponding piezoelectric element 60 so that ink is ejected from the ejection portion 600 of the ejection module 23-1 is located closest to the connection portion CN2 among the multiple drive circuits 52 arranged side by side on the wiring board 810 along the X2 direction, and the drive circuit 52c6 that outputs the drive signal COMC6 that drives the corresponding piezoelectric element 60 so that ink is not ejected from the ejection portion 600 of the ejection module 23-6 is located furthest from the connection portion CN2 among the multiple drive circuits 52 arranged side by side on the wiring board 810 along the X2 direction.

[0180] Therefore, the length of the wiring WA1 electrically connecting the drive circuit 52a1 and the connection part CN2 is shorter than the wiring WA2 to WA6, WB1 to WB6, WC1 to WC6 electrically connecting each of the drive circuits 52a2 to 52a6, 52b1 to 52b6, 52c1 to 52c6 to the connection part CN2, and the length of the wiring WC6 electrically connecting the drive circuit 52c6 to the connection part CN2 is longer than the wiring WA1 to WA6, WB1 to WB6, WC1 to WC5 electrically connecting each of the drive circuits 52a1 to 52a6, 52b1 to 52b6, 52c1 to 52c5 to the connection part CN2. That is, the wiring board 810 includes a plurality of wiring patterns that electrically connect a plurality of drive circuits 52 and the connection portion CN2, and among the plurality of wiring patterns, the length of the wiring WA1 that electrically connects the drive circuit 52a1 and the connection portion CN2 is the shortest, and the length of the wiring WC6 that electrically connects the drive circuit 52c6 and the connection portion CN2 is the longest.

[0181] In the head driving module 10 configured as described above, the voltage amplitude of the drive signals COMA1 and COMB1, which drive the piezoelectric element 60 to eject ink from the nozzle N of the ejection module 23-1, is larger than the voltage amplitude of the drive signal COMC1, which drives the piezoelectric element 60 to prevent ink from being ejected from the nozzle N of the ejection module 23-1. That is, the amount of current generated by the propagation of the drive signals COMA1 and COMB1 is larger than the amount of current generated by the propagation of the drive signal COMC1. Therefore, the drive signals COMA1 and COMB1 are more susceptible to the influence of impedance generated in the wiring pattern than the drive signal COMC1. By shortening the wiring lengths of the wirings WA1 and WB1 through which the drive signals COMA1 and COMB1 propagate, which are susceptible to the influence of impedance generated in the wiring pattern, compared to the wiring length of the wiring WC1 through which the drive signal COMC1 propagates, the waveform accuracy of the drive signals COMA1 and COMB1, which directly contribute to ink ejection, can be improved. As a result, the ink ejection accuracy of the liquid ejection device 1 is improved.

[0182] Furthermore, the amount of ink ejected from the corresponding nozzle N when drive signal COMA1 is supplied to the piezoelectric element 60 is greater than the amount of ink ejected from the corresponding nozzle N when drive signal COMB1 is supplied to the piezoelectric element 60, and therefore the voltage amplitude of drive signal COMA1 is greater than the voltage amplitude of drive signal COMB1, and the amount of current generated in conjunction with the propagation of drive signal COMA1 is greater than the amount of current generated in conjunction with the propagation of drive signal COMB1. Therefore, by making the wiring length of wiring WA1 through which drive signal COMA1 propagates shorter than the wiring length of wiring WB1 through which drive signal COMB1 propagates, the risk of a decrease in the waveform accuracy of drive signal COMA1 due to the influence of impedance generated in the wiring pattern is reduced.

[0183] Similarly, the amount of current generated by the propagation of drive signals COMA2 and COMB2 supplied to the piezoelectric element 60 of the ejection module 23-2 is greater than the amount of current generated by the propagation of drive signal COMC2, and the amount of current generated by the propagation of drive signal COMA2 is greater than the amount of current generated by the propagation of drive signal COMB2. Therefore, by making the wiring lengths of the wirings WA2 and WB2 through which drive signals COMA2 and COMB2 are propagated shorter than the wiring length of the wiring WC2 through which drive signal COMC2 is propagated, it is possible to improve the waveform accuracy of drive signals COMA2 and COMB2 output from the head driving module 10. Furthermore, by making the wiring length of the wiring WA2 through which drive signal COMA2 is propagated shorter than the wiring length of the wiring WB2 through which drive signal COMB2 is propagated, the risk of the waveform accuracy of drive signal COMA2 being reduced is reduced, and the ink ejection accuracy of the liquid ejection device 1 is improved.

[0184] Similarly, the amount of current generated by the propagation of drive signals COMA3 and COMB3 supplied to the piezoelectric element 60 of the ejection module 23-3 is greater than the amount of current generated by the propagation of drive signal COMC3, and the amount of current generated by the propagation of drive signal COMA3 is greater than the amount of current generated by the propagation of drive signal COMB3. Therefore, by making the wiring lengths of the wirings WA3 and WB3 through which drive signals COMA3 and COMB3 propagate shorter than the wiring length of the wiring WC3 through which drive signal COMC3 propagates, it is possible to improve the waveform accuracy of drive signals COMA3 and COMB3 output from the head driving module 10. Furthermore, by making the wiring length of the wiring WA3 through which drive signal COMA3 propagates shorter than the wiring length of the wiring WB3 through which drive signal COMB3 propagates, the risk of the waveform accuracy of drive signal COMA3 decreasing is reduced, and the ink ejection accuracy of the liquid ejection device 1 is improved.

[0185] Similarly, the amount of current generated by the propagation of drive signals COMA4 and COMB4 supplied to the piezoelectric element 60 of the ejection module 23-4 is greater than the amount of current generated by the propagation of drive signal COMC4, and the amount of current generated by the propagation of drive signal COMA4 is greater than the amount of current generated by the propagation of drive signal COMB4. Therefore, by making the wiring lengths of the wirings WA4 and WB4 through which drive signals COMA4 and COMB4 are propagated shorter than the wiring length of the wiring WC4 through which drive signal COMC4 is propagated, it is possible to improve the waveform accuracy of drive signals COMA4 and COMB4 output from the head driving module 10. Furthermore, by making the wiring length of the wiring WA4 through which drive signal COMA4 is propagated shorter than the wiring length of the wiring WB4 through which drive signal COMB4 is propagated, the risk of the waveform accuracy of drive signal COMA4 decreasing is reduced, and the ink ejection accuracy of the liquid ejection device 1 is improved.

[0186] Similarly, the amount of current generated by the propagation of drive signals COMA5 and COMB5 supplied to the piezoelectric element 60 of the ejection module 23-5 is greater than the amount of current generated by the propagation of drive signal COMC5, and the amount of current generated by the propagation of drive signal COMA5 is greater than the amount of current generated by the propagation of drive signal COMB5. Therefore, by making the wiring lengths of the wirings WA5 and WB5 through which drive signals COMA5 and COMB5 are propagated shorter than the wiring length of the wiring WC5 through which drive signal COMC5 is propagated, it is possible to improve the waveform accuracy of the drive signals COMA5 and COMB5 output from the head driving module 10. Furthermore, by making the wiring length of the wiring WA5 through which drive signal COMA5 is propagated shorter than the wiring length of the wiring WB5 through which drive signal COMB5 is propagated, the risk of the waveform accuracy of the drive signal COMA5 decreasing is reduced, and the ink ejection accuracy of the liquid ejection device 1 is improved.

[0187] Similarly, the amount of current generated by the propagation of drive signals COMA6 and COMB6 supplied to the piezoelectric element 60 of the ejection module 23-6 is greater than the amount of current generated by the propagation of drive signal COMC6, and the amount of current generated by the propagation of drive signal COMA6 is greater than the amount of current generated by the propagation of drive signal COMB6. Therefore, by making the wiring lengths of the wirings WA6 and WB6 through which drive signals COMA6 and COMB6 are propagated shorter than the wiring length of the wiring WC6 through which drive signal COMC6 is propagated, it is possible to improve the waveform accuracy of the drive signals COMA6 and COMB6 output from the head driving module 10. Furthermore, by making the wiring length of the wiring WA6 through which drive signal COMA6 is propagated shorter than the wiring length of the wiring WB6 through which drive signal COMB6 is propagated, the risk of the waveform accuracy of the drive signal COMA6 being reduced is reduced, and the ink ejection accuracy of the liquid ejection device 1 is improved.

[0188] Furthermore, in the liquid ejection device 1 of the first embodiment, the drive circuits 52a1 to 52a6, 52b1 to 52b6 that output drive signals COMA1 to COMA6, COMB1 to COMB6 that drive the piezoelectric elements 60 of the ejection modules 23-1 to 23-6 so that ink is ejected from the corresponding nozzles N are located closer to the connection part CN2 than the drive circuits 52c1 to 52c6 that output drive signals COMC1 to COMC6 that drive the piezoelectric elements 60 of the ejection modules 23-1 to 23-6 so that ink is not ejected from the corresponding nozzles N. As a result, as shown in Figures 15 to 17, the wiring lengths of the wirings WA1 to WA6, WB1 to WB6 that electrically connect each of the drive circuits 52a1, 52b1, 52a2, 52b2, 52a3, 52b3, 52a4, 52b4, 52a5, 52b5, 52a6, and 52b6 to the connection part CN2 and propagate the drive signals COMA1 to COMA6, COMB1 to COMB6 can be made shorter than the wiring lengths of the wirings WC1 to WC6 that electrically connect each of the drive circuits 52c1, 52c2, 52c3, 52c4, 52c5, and 52c6 to the connection part CN2 and propagate the drive signals COMC1 to COMC6.

[0189] That is, the wiring lengths of the wirings WA1-WA6, WB1-WB6 through which the drive signals COMA1-COMA6, COMB1-COMB6, which have large amounts of current generated during propagation, propagate can be made shorter than the wiring lengths of the wirings WC1-WC6 through which the drive signals COMC1-COMC6, which have small amounts of current generated during propagation, propagate. As a result, the waveform accuracy of the drive signals COMA1-COMA6, COMB1-COMB6, which directly contribute to ink ejection, can be further improved. This further improves the ink ejection accuracy of the liquid ejection device 1.

[0190] Here, in the drive circuit board 800 of the first embodiment, the drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 are provided on the first layer 831 of the wiring board 810, the wiring WA1 to WA6 that propagate drive signals COMA1 to COMA6 are provided on the second layer 832 of the wiring board 810, the wiring WB1 to WB6 that propagate drive signals COMB1 to COMB6 are provided on the third layer 833, and the wiring WC1 to WC6 that propagate drive signals COMC1 to COMC6 are provided on the fourth layer 834. However, this is not limited to this, and for example, some of the drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 may be provided on the second layer 832, the third layer 833, the fourth layer 834, or the fifth layer 835. Furthermore, at least some of the wiring WA1 to WA6 that propagate the drive signals COMA1 to COMA6, the wiring WB1 to WB6 that propagate the drive signals COMB1 to COMB6, and the wiring WC1 to WC6 that propagate the drive signals COMC1 to COMC6 may be provided in the same wiring layer. Furthermore, in the drive circuit board 800 of the first embodiment, the second layer 832, the third layer 833, and the fourth layer 834 are illustrated as being stacked in this order along the Z2 direction from the +Z2 side to the -Z2 side, but the stacking order in the wiring board 810 is not limited to this. Furthermore, in the first embodiment, the wiring board 810 has been described as having the second layer 832, the third layer 833, and the fourth layer 834 as inner layers, but the wiring board 810 may also include multiple inner layers, such as a layer through which the reference voltage signals VBS1 to VBS6 are propagated, a layer through which various control signals including the data signal DATA are propagated, and a layer maintained at ground potential.

[0191] 14, wiring board 810 has a plurality of through holes 820 through which a plurality of screws 780 are inserted. Some of the plurality of through holes 820 are arranged side by side along side 813 of wiring board 810, and some different of the plurality of through holes 820 are arranged side by side along side 814 of wiring board 810. That is, wiring board 810 has a plurality of through holes 820 arranged side by side in two rows along the X2 direction. Here, "arranged side by side along the side 813 of the wiring board 810" means that the plurality of through holes 820 are arranged side by side along the X2 direction in a state where the shortest distance between each of the plurality of through holes 820 arranged side by side and the side 813 of the wiring board 810 is shorter than the shortest distance between each of the plurality of through holes 820 arranged side by side and the side 814 of the wiring board 810, and "arranged side by side along the side 814 of the wiring board 810" means that the plurality of through holes 820 are arranged side by side along the X2 direction in a state where the shortest distance between each of the plurality of through holes 820 arranged side by side and the side 814 of the wiring board 810 is shorter than the shortest distance between each of the plurality of through holes 820 arranged side by side and the side 813 of the wiring board 810.

[0192] At least one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are located between connection portion CN2 and drive circuit 52a1. In other words, at least one of the plurality of through holes 820 is located between connection portion CN2 and drive circuit 52a1 in the direction along the X2 direction.

[0193] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are positioned between drive circuits 52a1 and 52b1. In other words, at least one of the plurality of through holes 820 is positioned between drive circuits 52a1 and 52b1 in the direction along the X2 direction.

[0194] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are positioned between drive circuits 52b1 and 52a2. In other words, at least one of the plurality of through holes 820 is positioned between drive circuits 52b1 and 52a2 in the direction along the X2 direction.

[0195] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are located between drive circuits 52a2 and 52b2. In other words, at least one of the plurality of through holes 820 is located between drive circuits 52a2 and 52b2 in the direction along the X2 direction.

[0196] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are located between drive circuit 52b2 and drive circuit 52a3. In other words, at least one of the plurality of through holes 820 is located between drive circuit 52b2 and drive circuit 52a3 in the direction along the X2 direction.

[0197] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are located between drive circuits 52a3 and 52b3. In other words, at least one of the plurality of through holes 820 is located between drive circuits 52a3 and 52b3 in the direction along the X2 direction.

[0198] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are located between drive circuit 52b3 and drive circuit 52a4. In other words, at least one of the plurality of through holes 820 is located between drive circuit 52b3 and drive circuit 52a4 in the X2 direction.

[0199] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are located between drive circuits 52a4 and 52b4. In other words, at least one of the plurality of through holes 820 is located between drive circuits 52a4 and 52b4 in the direction along the X2 direction.

[0200] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are located between drive circuit 52b4 and drive circuit 52a5. In other words, at least one of the plurality of through holes 820 is located between drive circuit 52b4 and drive circuit 52a5 in the X2 direction.

[0201] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are located between drive circuits 52a5 and 52b5. In other words, at least one of the plurality of through holes 820 is located between drive circuits 52a5 and 52b5 in the direction along the X2 direction.

[0202] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are located between drive circuit 52b5 and drive circuit 52a6. In other words, at least one of the plurality of through holes 820 is located between drive circuit 52b5 and drive circuit 52a6 in the X2 direction.

[0203] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are positioned between drive circuits 52a6 and 52b6. In other words, at least one of the plurality of through holes 820 is positioned between drive circuits 52a6 and 52b6 in the direction along the X2 direction.

[0204] At least one different one of the plurality of through holes 820 arranged in a row along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged in a row along side 814 of wiring substrate 810 are located between drive circuit 52b6 and drive circuit 52c1. In other words, at least one of the plurality of through holes 820 is located between drive circuit 52b6 and drive circuit 52c1 in the direction along the X2 direction.

[0205] At least one different one of the plurality of through holes 820 arranged side by side along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged side by side along side 814 of wiring substrate 810 are located between drive circuit 52c3 and drive circuit 52c4, at least one different one of the plurality of through holes 820 arranged side by side along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged side by side along side 814 of wiring substrate 810 are located between drive circuit 52c6 and integrated circuit 101, and at least one different one of the plurality of through holes 820 arranged side by side along side 813 of wiring substrate 810 and at least one different one of the plurality of through holes 820 arranged side by side along side 814 of wiring substrate 810 are located between integrated circuit 101 and connection portion CN1.

[0206] That is, the wiring board 810 is provided with wiring between the drive circuits 52a1 and 52b1 that output drive signals COMA1 and COMB1 to drive the piezoelectric element 60 so that ink is ejected from the ejection module 23-1, between the drive circuits 52a2 and 52b2 that output drive signals COMA2 and COMB2 to drive the piezoelectric element 60 so that ink is ejected from the ejection module 23-2, between the drive circuits 52a3 and 52b3 that output drive signals COMA3 and COMB3 to drive the piezoelectric element 60 so that ink is ejected from the ejection module 23-3, and between the drive circuits 52a4 and 52b4 that output drive signals COMA5 and COMB6 to drive the piezoelectric element 60 so that ink is ejected from the ejection module 23-4. Through holes 820 are located between drive circuits 52a4 and 52b4 that output drive signals COMA4 and COMB4 to drive the piezoelectric element 60 so that ink is ejected from module 23-4, between drive circuits 52a5 and 52b5 that output drive signals COMA5 and COMB5 to drive the piezoelectric element 60 so that ink is ejected from ejection module 23-5, and between drive circuits 52a1 and 52b1 that output drive signals COMA6 and COMB6 to drive the piezoelectric element 60 so that ink is ejected from ejection module 23-6.

[0207] Furthermore, when the drive circuits 52a1, 52b1 that output drive signals COMA1, COMB1 and the drive circuits 52a2, 52b2 that output drive signals COMA2, COMB2 as shown in FIG. 14 are positioned adjacent to each other along the X2 direction, it is preferable that the through hole 820 be positioned between the drive circuits 52a1, 52b1 and the drive circuits 52a2, 52b2. Similarly, when the drive circuits 52a2 and 52b2 that output drive signals COMA2 and COMB2 and the drive circuits 52a3 and 52b3 that output drive signals COMA3 and COMB3 are positioned adjacent to each other along the X2 direction, it is preferable that the through-hole 820 be positioned between the drive circuits 52a2 and 52b2 and the drive circuits 52a3 and 52b3. When the drive circuits 52a3 and 52b3 that output drive signals COMA3 and COMB3 and the drive circuits 52a4 and 52b4 that output drive signals COMA4 and COMB4 are positioned adjacent to each other along the X2 direction, it is preferable that the through-hole 820 be positioned between the drive circuits 52a3 and 52b3 and the drive circuits 52a4 and 52b4. Furthermore, when the drive circuits 52a4, 52b4 that output drive signals COMA4, COMB4 and the drive circuits 52a5, 52b5 that output drive signals COMA5, COMB5 are positioned adjacent to each other along the X2 direction, it is preferable that the through hole 820 be located between the drive circuits 52a4, 52b4 and the drive circuits 52a5, 52b5, and when the drive circuits 52a5, 52b5 that output drive signals COMA5, COMB5 and the drive circuits 52a6, 52b6 that output drive signals COMA6, COMB6 are positioned adjacent to each other along the X2 direction, it is preferable that the through hole 820 be located between the drive circuits 52a5, 52b5 and the drive circuits 52a6, 52b6.

[0208] 12, a specific example of the structure of the heat sink 710 of the head drive module 10 will now be described. The heat sink 710 is located on the +Z2 side of the drive circuit board 800. The heat sink 710 includes a bottom 711, side portions 712 and 713, protrusions 715, 716, and 717, and a plurality of fins 718.

[0209] 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 accommodated in the accommodation 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.

[0210] The protrusions 715, 716, and 717 are provided inside 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 provided on the wiring board 810, respectively. The protrusion 715 is located corresponding to the inductor L1 provided on the wiring board 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 board 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 board 810, protrudes from the bottom 711 toward the -Z2 side, and extends along the X2 direction.

[0211] 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 fin portions 718 that such a heat sink 710 has is set based on an optimal spacing that is determined depending on the amount of heat generated in the drive circuit board 800 that the heat sink 710 dissipates, the length of the fin portions 718 in the Z2 direction, the airflow acting on the fin portions 718, and the like.

[0212] The heat sink 710 configured as described above is attached to the wiring board 810 of the drive circuit board 800, and dissipates heat generated by the multiple drive circuits 52 provided on the wiring board 810. In other words, the head drive module 10 is provided with a heat sink 710 that is attached to the wiring board 810 and dissipates heat from at least one of the multiple drive circuits 52. Such a heat sink 710 is made of a material that has high thermal conductivity and sufficient rigidity to protect the drive circuits 52, and is made of a metal such as aluminum, iron, or copper.

[0213] Furthermore, in the head drive module 10 of the first embodiment, the heat sink 710 is made of a metal such as aluminum, iron, or copper, and is provided to cover the multiple drive circuits 52. As a result, the heat sink 710 not only dissipates heat generated by the multiple drive circuits 52, but also functions as a shielding material that reduces the risk of external noise contributing to the multiple drive circuits 52. This further improves the waveform accuracy of the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 output by the multiple drive circuits 52.

[0214] The heat conduction member group 720 is positioned between the drive circuit board 800 and the heat sink 710 in the Z2 direction. The heat conduction member group 720 contacts both the heat-generating electronic components of the drive circuit board 800 and the heat sink 710, thereby increasing the efficiency of heat conduction from the drive circuit board 800 to the heat sink 710. The 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 heat conduction member that conducts heat generated in the drive circuit board 800 to the heat sink 710, as well as an insulating member that ensures electrical insulation between the drive circuit board 800 and the heat sink 710. Furthermore, the heat conduction member group 720 also functions as a buffer member that relieves stress that occurs when the heat sink 710 is attached to the drive circuit board 800.

[0215] 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, and is in contact with both the inductor L1 of each of the multiple drive circuits 52 and the protrusion 715 when the heat sink 710 is attached to the drive circuit board 800. This increases the efficiency of the thermal conduction member 730 in conducting 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, and is in contact with both the transistor M1 of each of the multiple drive circuits 52 and the protrusion 716 when the heat sink 710 is attached to the drive circuit board 800. 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, and comes into contact with both the transistor M2 of each of the multiple drive circuits 52 and the protrusion 716 when the heat sink 710 is attached to the drive circuit board 800. 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, and comes into contact with both the integrated circuit 500 of each of the multiple drive circuits 52 and the protrusion 717 when the heat sink 710 is attached to the drive circuit board 800. This allows the thermal conductive member 760 to increase the efficiency of conducting heat generated in the transistor M2 to the heat sink 710.

[0216] Each of the multiple screws 780 is made of a metal such as steel, iron, aluminum, or stainless steel, and is inserted from the -Z2 side toward the +Z2 side through each of the multiple through holes 820 of the wiring board 810 of the drive circuit board 800, and is tightened to the heat sink 710 located on the +Z2 side of the drive circuit board 800, thereby attaching the heat sink 710 to the wiring board 810 of the drive circuit board 800.

[0217] Specifically, some of the screws 780 are inserted through through holes 820 located between the connection portion CN2 and the drive circuit 52a1, among the through holes 820 formed in the wiring substrate 810. Then, the screws 780 are fastened to the side portions 712, 713 of the heat sink 710, thereby attaching the heat sink 710 to the wiring substrate 810.

[0218] Similarly, some of the multiple screws 780 are inserted into through holes 820 arranged in a row along a side 813 of the wiring board 810, including a through hole 820 located between the drive circuit 52a1 and the drive circuit 52b1, a through hole 820 located between the drive circuit 52b1 and the drive circuit 52a2, a through hole 820 located between the drive circuit 52a2 and the drive circuit 52b2, a through hole 820 located between the drive circuit 52b2 and the drive circuit 52a3, a through hole 820 located between the drive circuit 52a3 and the drive circuit 52b3, a through hole 820 located between the drive circuit 52b3 and the drive circuit 52a4, and a through hole 820 located between the drive circuit 52a4 and the drive circuit 52b4. 5 and 6. Screws 780 are inserted through through holes 820 located between drive circuits 52b4 and 52a5, through holes 820 located between drive circuits 52a5 and 52b5, through holes 820 located between drive circuits 52b5 and 52a6, through holes 820 located between drive circuits 52a6 and 52b6, through holes 820 located between drive circuits 52b6 and 52c1, through holes 820 located between drive circuits 52c3 and 52c4, through holes 820 located between drive circuit 52c6 and integrated circuit 101, and through holes 820 located between integrated circuit 101 and connection portion CN1. Screws 780 are then fastened to side portions 712 and 713 of heat sink 710, thereby attaching heat sink 710 to wiring board 810.

[0219] As described above, the heat sink 710 including the side portions 712 and 713 is attached to the wiring board 810 of the drive circuit board 800 by inserting the screws 780 through the through holes 820 of the wiring board 810 and fastening them to the side portions 712 and 713. As a result, the heat conduction member 730 is in close contact with both the inductor L1 and the protruding portion 715, the heat conduction member 740 is in close contact with both the transistor M1 and the protruding portion 716, the heat conduction member 750 is in close contact with both the transistor M2 and the protruding portion 716, and the heat conduction member 750 is in close contact with both the integrated circuit 500 and the protruding portion 717. In other words, the thermal contact efficiency between the inductor L1, the transistors M1 and M2, the integrated circuit 500, and the heat sink 710, which generate a large amount of heat, is improved. As a result, heat generated by the inductor L1, the transistors M1 and M2, and the integrated circuit 500, which generate a large amount of heat, can be conducted to the heat sink 710 more efficiently, and the temperature rise of the drive circuit 52 included in the drive circuit board 800 is reduced.

[0220] Here, the drive circuit 52a1 outputs a drive signal COMA1 that drives the piezoelectric element 60 of the ejection module 23-1 so that a large amount of ink is ejected from the liquid ejection module 20, the drive circuit 52b1 outputs a drive signal COMB1 that drives the piezoelectric element 60 of the ejection module 23-1 so that a small amount of ink is ejected from the liquid ejection module 20, and the drive circuit 52c1 outputs a drive signal COMC1 that drives the piezoelectric element 60 of the ejection module 23-1 so that no ink is ejected from the liquid ejection module 20. Therefore, the heat generation amounts of the drive circuits 52a1 and 52b1 are greater than that of the drive circuit 52c1, and the heat generation amount of the drive circuit 52a1 is greater than that of the drive circuit 52b1.

[0221] Such drive circuits 52a1, 52b1, and 52c1 are positioned on a first layer 831 of wiring substrate 810, lined up in the X2 direction in the order of drive circuits 52a1, 52b1, and 52c1, and a through-hole 820 through which a screw 780 is inserted is positioned between drive circuits 52a1 and 52b1, which generate a large amount of heat. That is, heat sink 710 is attached to wiring substrate 810 by metal screws 780 between drive circuit 52a1, which outputs drive signal COMA1 that drives piezoelectric element 60 to eject ink, and drive circuit 52b1, which outputs drive signal COMB1 that drives piezoelectric element 60 to eject ink. As a result, heat generated by drive circuits 52a1 and 52b1 and conducted to wiring substrate 810 is released to heat sink 710 via metal screws 780. That is, the heat generated by drive circuits 52a1 and 52b1 is conducted to heat sink 710 via heat conduction members 730, 740, 750, and 760, and is also conducted to heat sink 710 via metal screw 780. This improves the heat dissipation efficiency of drive circuits 52a1 and 52b1, which generate a large amount of heat.

[0222] Similarly, the amount of heat generated by drive circuits 52a2 and 52b2 is greater than the amount of heat generated by drive circuit 52c2, and the amount of heat generated by drive circuit 52a2 is greater than the amount of heat generated by drive circuit 52b2. Such drive circuits 52a2, 52b2, and 52c2 are positioned on first layer 831 of wiring substrate 810, lined up in the X2 direction in the order of drive circuits 52a2, 52b2, and 52c2, and through-hole 820, through which screw 780 is inserted, is positioned between drive circuits 52a2 and 52b2. As a result, of the heat generated by drive circuits 52a2 and 52b2, the heat conducted to wiring substrate 810 is released to heat sink 710 via metal screw 780. That is, the heat generated by drive circuits 52a2 and 52b2 is conducted to heat sink 710 via heat conduction members 730, 740, 750, and 760, and is also conducted to heat sink 710 via metal screw 780. This improves the heat dissipation efficiency of drive circuits 52a2 and 52b2, which generate a large amount of heat.

[0223] Similarly, the amount of heat generated by drive circuits 52a3 and 52b3 is greater than the amount of heat generated by drive circuit 52c3, which in turn is greater than the amount of heat generated by drive circuit 52a3. Drive circuits 52a3, 52b3, and 52c3 are arranged side by side in the X2 direction on first layer 831 of wiring substrate 810 in the order of drive circuits 52a3, 52b3, and 52c3, and through-hole 820 through which screw 780 is inserted is located between drive circuits 52a3 and 52b3. This allows heat generated by drive circuits 52a3 and 52b3 and conducted to wiring substrate 810 to be released to heat sink 710 via metal screw 780. That is, the heat generated by drive circuits 52a3 and 52b3 is conducted to heat sink 710 via heat conduction members 730, 740, 750, and 760, and is also conducted to heat sink 710 via metal screw 780. This improves the heat dissipation efficiency of drive circuits 52a3 and 52b3, which generate a large amount of heat.

[0224] Similarly, the amount of heat generated by drive circuits 52a4 and 52b4 is greater than the amount of heat generated by drive circuit 52c4, which in turn is greater than the amount of heat generated by drive circuit 52a4. Such drive circuits 52a4, 52b4, and 52c4 are positioned on first layer 831 of wiring substrate 810, lined up in the X2 direction in the order of drive circuits 52a4, 52b4, and 52c4, and through-hole 820, through which screw 780 is inserted, is positioned between drive circuits 52a4 and 52b4. As a result, of the heat generated by drive circuits 52a4 and 52b4, the heat conducted to wiring substrate 810 is released to heat sink 710 via metal screw 780. That is, the heat generated by drive circuits 52a4 and 52b4 is conducted to heat sink 710 via heat conduction members 730, 740, 750, and 760, and is also conducted to heat sink 710 via metal screw 780. This improves the heat dissipation efficiency of drive circuits 52a4 and 52b4, which generate a large amount of heat.

[0225] Similarly, the amount of heat generated by drive circuits 52a5 and 52b5 is greater than the amount of heat generated by drive circuit 52c5, which in turn is greater than the amount of heat generated by drive circuit 52a5. Drive circuits 52a5, 52b5, and 52c5 are arranged side by side in the X2 direction on first layer 831 of wiring substrate 810 in the order of drive circuits 52a5, 52b5, and 52c5, and through-hole 820 through which screw 780 is inserted is located between drive circuits 52a5 and 52b5. This allows heat generated by drive circuits 52a5 and 52b5 that is conducted to wiring substrate 810 to be released to heat sink 710 via metal screw 780. That is, the heat generated by drive circuits 52a5 and 52b5 is conducted to heat sink 710 via heat conduction members 730, 740, 750, and 760, and is also conducted to heat sink 710 via metal screw 780. This improves the heat dissipation efficiency of drive circuits 52a5 and 52b5, which generate a large amount of heat.

[0226] Similarly, the amount of heat generated by drive circuits 52a6 and 52b6 is greater than the amount of heat generated by drive circuit 52c6, which in turn is greater than the amount of heat generated by drive circuit 52a6. Drive circuits 52a6, 52b6, and 52c6 are arranged side by side in the X2 direction on first layer 831 of wiring substrate 810 in the order of drive circuits 52a6, 52b6, and 52c6, and through-hole 820 through which screw 780 is inserted is located between drive circuits 52a6 and 52b6. This allows heat generated by drive circuits 52a6 and 52b6 that is conducted to wiring substrate 810 to be released to heat sink 710 via metal screw 780. That is, the heat generated by drive circuits 52a6 and 52b6 is conducted to heat sink 710 via heat conduction members 730, 740, 750, and 760, and is also conducted to heat sink 710 via metal screw 780. This improves the heat dissipation efficiency of drive circuits 52a6 and 52b6, which generate a large amount of heat.

[0227] Furthermore, in the liquid ejection device 1 of the first embodiment, the drive circuits 52a1 to 52a6, 52b1 to 52b6 that output drive signals COMA1 to COMA6, COMB1 to COMB6 that drive the piezoelectric elements 60 to eject ink are positioned adjacent to each other for each corresponding ejection module 23 along the X2 direction of the wiring board 810, and the drive circuits 52c1 to 52c6 that output drive signals COMC1 to COMC6 that drive the piezoelectric elements 60 not to eject ink are positioned adjacent to each other in the order of drive circuits 52c1, 52c2, 52c3, 52c4, 52c5, 52c6 along the X2 direction of the wiring board 810 on the +X2 side of the drive circuits 52a1 to 52a6, 52b1 to 52b6.

[0228] In such a head drive module 10, the wiring board 810 has through holes 820 between the drive circuits 52b1 and 52a2, between the drive circuits 52b2 and 52a3, between the drive circuits 52b3 and 52a4, between the drive circuits 52b4 and 52a5, and between the drive circuits 52b5 and 52a6. Heat sink 710 is attached to wiring board 810 by screws 780 inserted through through holes 820 located respectively between drive circuits 52a1 to 52a6 and 52b1 to 52b6, between drive circuits 52b4 and 52a5, and between drive circuits 52b5 and 52a6. This makes it possible to further increase the efficiency of dissipating heat generated in drive circuits 52a1 to 52a6 and 52b1 to 52b6, even when drive circuits 52a1 to 52a6 and 52b1 to 52b6, which generate a large amount of heat, are concentrated on wiring board 810.

[0229] Here, in the head drive module 10, the heat sink 710 may be attached to the drive circuit board 800 using, for example, metal rivets instead of the multiple metal screws 780. Alternatively, the heat sink 710 may be attached to the drive circuit board 800 by inserting a portion of the heat sink 710 into the through-hole 820 and attaching the portion of the heat sink 710 that has inserted into the through-hole 820 to a metal portion of the drive circuit board 800 with solder or the like. However, in a configuration in which the multiple drive circuits 52 of the drive circuit board 800 are housed inside the heat sink 710 as shown in the first embodiment, attaching the heat sink 710 to the drive circuit board 800 using metal rivets, solder, or the like reduces the maintainability of the drive circuit board 800. That is, from the perspective of improving the maintainability of the drive circuit board 800, it is preferable to use metal screws 780 that allow the drive circuit board 800 and the heat sink 710 to be easily attached and detached and have excellent thermal conductivity.

[0230] 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.

[0231] Specifically, the cooling fan 770 is attached so as to cover the opening 714. The opening 714 is a through-hole that passes through the heat sink 710 in the Z2 direction, and communicates with the interior of the head drive module 10 when the heat sink 710 is attached to the drive circuit board 800. When the cooling fan 770 operates, outside air is introduced into the head drive module 10 through the opening 714. This improves the efficiency of circulation of air floating inside the head drive module 10, and improves the efficiency with which the heat sink 710 dissipates heat generated in the drive circuit board 800.

[0232] Here, the cooling fan 770 only needs to be attached in a way that increases the efficiency of circulation of air floating inside the head drive module 10, and may be provided on any of the +X2, -X2, +Y2, or -Y2 sides of the head drive module 10. Furthermore, the operation of the cooling fan 770 to introduce outside air into the head drive module 10 is not limited to the operation of the cooling fan 770 to take in outside air into the head drive module 10, but also includes the case where the cooling fan 770 operates to exhaust air floating inside the head drive module 10.

[0233] In the liquid ejection device 1 configured as above, the piezoelectric element 60 included in the ejection module 23-1 is an example of a first piezoelectric element, the piezoelectric element 60 included in the ejection module 23-2 is an example of a second piezoelectric element, and the piezoelectric element 60 included in the ejection module 23-1 and the liquid ejection module 20 that ejects ink in response to the driving of the piezoelectric element 60 included in the ejection module 23-1 are an example of an ejection head. The head driving module 10 that drives the liquid ejection module 20 corresponds to a head driving circuit.

[0234] Furthermore, the drive signal COMA1 that drives the piezoelectric element 60 included in the ejection module 23-1 is an example of a first drive signal, the drive signal COMB1 is an example of a second drive signal, the drive signal COMC1 is an example of a third drive signal, the drive circuit 52a1 that outputs the drive signal COMA1 is an example of a first drive circuit, the drive circuit 52b1 that outputs the drive signal COMB1 is an example of a second drive circuit, and the drive circuit 52c1 that outputs the drive signal COMC1 is an example of a third drive circuit. The amount of ink ejected when the drive signal COMA1 is supplied to the piezoelectric element 60 is an example of a first ejection amount, and the amount of ink ejected when the drive signal COMB1 is supplied to the piezoelectric element 60 is an example of a second ejection amount.

[0235] Furthermore, the drive signal COMA2 that drives the piezoelectric element 60 included in the ejection module 23-2 is an example of a fourth drive signal, the drive signal COMB2 is an example of a fifth drive signal, the drive signal COMC2 is an example of a sixth drive signal, the drive circuit 52a2 that outputs the drive signal COMA2 is an example of a fourth drive circuit, the drive circuit 52b2 that outputs the drive signal COMB2 is an example of a fifth drive circuit, and the drive circuit 52c2 that outputs the drive signal COMC2 is an example of a sixth drive circuit. The amount of ink ejected when the drive signal COMA2 is supplied to the piezoelectric element 60 is an example of a third ejection amount, and the amount of ink ejected when the drive signal COMB2 is supplied to the piezoelectric element 60 is an example of a fourth ejection amount.

[0236] Furthermore, wiring substrate 810 on which drive circuits 52a1, 52b1, 52c1, 52a2, 52b2, and 52c2 are provided is an example of a substrate, and the X2 direction in which drive circuits 52a1, 52b1, 52c1, 52a2, 52b2, and 52c2 are arranged on wiring substrate 810 is an example of one direction. Of the multiple through holes 820 provided in the wiring board 810, the through hole 820 located between the drive circuits 52a1 and 52b1 is an example of a first through hole, and the screw 780 inserted through the through hole 820 corresponding to the first through hole is an example of a first screw; of the multiple through holes 820 provided in the wiring board 810, the through hole 820 located between the drive circuits 52b1 and 52a2 is an example of a fourth through hole, and the screw 780 inserted through the through hole 820 corresponding to the fourth through hole is an example of a fourth screw; of the multiple through holes 820 provided in the wiring board 810, the through hole 820 located between the drive circuits 52a2 and 52b2 is an example of a fifth through hole, and the screw 780 inserted through the through hole 820 corresponding to the fifth through hole is an example of a fifth screw.

[0237] The heat sink 710 attached to the wiring board 810 by the screws 780 is an example of a metal frame.

[0238] 1.6 Effects In the liquid ejection device 1 of the first embodiment configured as described above, the head driving module 10 has a driving circuit 52a1 that outputs a driving signal COMA1 that drives the piezoelectric element 60 so that the liquid ejection module 20 ejects a large amount of ink, a driving circuit 52b1 that outputs a driving signal COMB1 that drives the piezoelectric element 60 so that the liquid ejection module 20 ejects a small amount of ink, a driving circuit 52c1 that outputs a driving signal COMC1 that drives the piezoelectric element 60 so that the liquid ejection module 20 does not eject ink, a wiring board 810 on which the driving circuits 52a1, 52b1, and 52c1 are arranged in the order of drive circuit 52a1, drive circuit 52b1, and drive circuit 52c1 along the X2 direction, and a heat sink 710 attached to the wiring board 810.

[0239] In this head driving module 10, the heat generated by the driving circuits 52a1 and 52b1 that output the driving signals COMA1 and COMB1 that drive the piezoelectric element 60 so that the liquid ejection module 20 ejects ink is greater than the heat generated by the driving circuit 52c1 that outputs the driving signal COMC1 that drives the piezoelectric element 60 so that the liquid ejection module 20 does not eject ink, and by positioning the through-holes 820 through which the screws 780 for attaching the heat sink 710 to the wiring board 810 are inserted between the driving circuits 52a1 and 52b1 that generate more heat, the heat generated by the driving circuits 52a1 and 52b1 that is conducted to the wiring board 810 is released to the heat sink 710 via the screws 780. This allows the heat generated in the head driving module 10 to be released more efficiently.

[0240] Furthermore, when the head driving module 10 includes, in addition to the driving circuits 52a1, 52b1, and 52c1, driving circuits 52a2 and 52b2 that output driving signals COMA2 and COMB2 to drive the piezoelectric element 60 so that the liquid ejection module 20 ejects ink, and a driving circuit 52c2 that outputs a driving signal COMC2 to drive the piezoelectric element 60 so that the liquid ejection module 20 does not eject ink, through holes 820 through which screws 780 for attaching the heat sink 710 to the wiring board 810 are inserted are located not only between the driving circuits 52a1 and 52b1, but also between the driving circuits 52a2 and 52b2 and between the driving circuits 52b1 and 52a2, so that the heat generated in the driving circuits 52a1, 52b1, 52a2, and 52b2 that is conducted to the wiring board 810 can be released to the heat sink 710 via the screws 780. That is, even if the head driving module 10 has multiple sets of driving circuits 52 that supply driving signals COM to different piezoelectric elements 60, the heat generated in the head driving module 10 can be dissipated more efficiently.

[0241] Furthermore, in the liquid ejection device 1 of this embodiment, in the head drive module 10, the heat generated by the multiple drive circuits 52, including the heat conducted to the wiring board 810, can also be efficiently conducted to the heat sink 710. Therefore, even if the transistors M1 and M2 included in the drive circuits 52 are surface-mounted types that conduct a large amount of heat to the wiring board 810, the heat generated by the drive circuits 52 can be efficiently conducted to the heat sink 710.

[0242] Furthermore, in the liquid ejection device 1 of the first embodiment, the head driving module 10 includes a driving circuit 52a1 that outputs a driving signal COMA1 that drives the piezoelectric element 60 of the ejection module 23-1 so that ink is ejected from the corresponding ejection section 600, a driving circuit 52c1 that outputs a driving signal COMC1 that drives the piezoelectric element 60 of the ejection module 23-1 so that ink is not ejected from the corresponding ejection section 600, a driving circuit 52a2 that outputs a driving signal COMA2 that drives the piezoelectric element 60 of the ejection module 23-2 so that ink is ejected from the corresponding ejection section 600, and a driving circuit 52c2 that outputs a driving signal COMC2 that drives the piezoelectric element 60 of the ejection module 23-2 so that ink is not ejected from the corresponding ejection section 600.

[0243] Here, the voltage amplitude of the drive signal COMA1 output by the drive circuit 52a1 drives the piezoelectric element 60 of the ejection module 23-1 to eject ink from the corresponding ejection section 600, and therefore is larger than the voltage amplitude of the drive signal COMC1 that drives the piezoelectric element 60 of the ejection module 23-1 to prevent ink from being ejected from the corresponding ejection section 600. Similarly, the voltage amplitude of the drive signal COMA2 output by the drive circuit 52a2 drives the piezoelectric element 60 of the ejection module 23-2 to eject ink from the corresponding ejection section 600, and therefore is larger than the voltage amplitude of the drive signal COMC2 that drives the piezoelectric element 60 of the ejection module 23-2 to prevent ink from being ejected from the corresponding ejection section 600. Therefore, the amount of heat generated by the drive circuit 52a1 is larger than the amount of heat generated by the drive circuit 52c1, and the amount of heat generated by the drive circuit 52a2 is larger than the amount of heat generated by the drive circuit 52c2. That is, the liquid ejection device 1 of the first embodiment includes, as the plurality of drive circuits 52, drive circuits 52a1, 52c1, 52a2, and 52c2 that generate different amounts of heat.

[0244] In the liquid ejection device 1 of the first embodiment, the drive circuit 52a2 is located between the drive circuits 52a1 and 52c1 along the X2 direction, and the drive circuits 52a1, 52c1, 52a2, and 52c2 are arranged side by side along the X2 direction on the wiring board 810 so that the shortest distance between the drive circuits 52c2 and 52c1 is shorter than the shortest distance between the drive circuits 52c2 and 52a2. That is, the drive circuits 52a1, 52c1, 52a2, and 52c2 are arranged side by side in the order of the drive circuits 52a1, 52a2, 52c1, and 52c2 along the X2 direction of the wiring board 810. In other words, on the wiring board 810, the drive circuits 52a1 and 52a2, which generate a large amount of heat, are arranged close to each other, and the drive circuits 52c1 and 52c2, which generate a small amount of heat, are arranged close to each other. This makes it easy to concentrate heat dissipation members such as heat sinks 710 for dissipating heat from the drive circuits 52 in the head drive module 10 on the drive circuits 52a1 and 52a2, which generate large amounts of heat. Furthermore, whether or not to dispose such heat dissipation members for the drive circuits 52c1 and 52c2, which generate small amounts of heat, can be easily selected depending on the usage environment and operating conditions of the liquid ejector 1. That is, in the liquid ejector 1 of the first embodiment, the drive circuits 52 that generate large amounts of heat are disposed together on the wiring board 810, and the drive circuits 52 that generate small amounts of heat are disposed together on the wiring board 810. This reduces the risk of the structure of heat dissipation members such as heat sinks 710 that dissipate heat from the multiple drive circuits 52 becoming complicated, and makes it possible to appropriately select whether or not to dispose such heat dissipation members depending on the amounts of heat generated by the multiple drive circuits 52. As a result, even when the liquid ejector 1 includes multiple drive circuits 52, it is possible to apply an optimal heat dissipation structure depending on the amount of heat generated by the multiple drive circuits 52, and to efficiently dissipate the heat generated by the multiple drive circuits 52.

[0245] Furthermore, in the liquid ejection device 1 of the first embodiment, the head driving module 10 includes a driving circuit 52b1 that outputs a driving signal COMB1 that drives the piezoelectric element 60 of the ejection module 23-1 so that ink is ejected from the corresponding ejection portion 600, and a driving circuit 52a2 that outputs a driving signal COMB2 that drives the piezoelectric element 60 of the ejection module 23-2 so that ink is ejected from the corresponding ejection portion 600. This makes it possible to control the amount of ink ejected from the ejection module 23-1 using the driving signals COMA1 and COMB1, and similarly, to control the amount of ink ejected from the ejection module 23-2 using the driving signals COMA2 and COMB2. In other words, more detailed control of the amount of ink ejected from each of the ejection modules 23-1 and 23-2 becomes possible, improving the quality of images formed on a medium.

[0246] In the liquid ejection device 1 of the first embodiment, the voltage amplitude of the drive signal COMB1 output by the drive circuit 52b1 drives the piezoelectric element 60 of the ejection module 23-1 to eject ink from the corresponding ejection section 600, and is therefore larger than the voltage amplitude of the drive signal COMC1 that drives the piezoelectric element 60 of the ejection module 23-1 to prevent ink from being ejected from the corresponding ejection section 600. Similarly, the voltage amplitude of the drive signal COMB2 output by the drive circuit 52b2 drives the piezoelectric element 60 of the ejection module 23-2 to eject ink from the corresponding ejection section 600, and is therefore larger than the voltage amplitude of the drive signal COMC2 that drives the piezoelectric element 60 of the ejection module 23-2 to prevent ink from being ejected from the corresponding ejection section 600. Therefore, the amount of heat generated by the drive circuit 52b1 is larger than the amount of heat generated by the drive circuit 52c1, and the amount of heat generated by the drive circuit 52b2 is larger than the amount of heat generated by the drive circuit 52c2.

[0247] In the liquid ejector 1 of the first embodiment, when the liquid ejector 1 includes a drive circuit 52b1 that outputs a drive signal COMB1 that drives the piezoelectric element 60 of the ejection module 23-1 so as to eject ink from the corresponding ejection portion 600, and a drive circuit 52a2 that outputs a drive signal COMB2 that drives the piezoelectric element 60 of the ejection module 23-2 so as to eject ink from the corresponding ejection portion 600, the drive circuits 52b1 and 52b2 are located between the drive circuits 52a1 and 52c1 and between the drive circuits 52a1 and 52c2 along the X2 direction. In other words, the drive circuits 52b1 and 52b2 that generate large amounts of heat are not located between the drive circuits 52c1 and 52c2 that generate small amounts of heat.

[0248] As a result, even when the liquid ejector 1 includes a drive circuit 52b1 that outputs a drive signal COMB1 that drives the piezoelectric element 60 of the ejection module 23-1 so that ink is ejected from the corresponding ejection portion 600, and a drive circuit 52a2 that outputs a drive signal COMB2 that drives the piezoelectric element 60 of the ejection module 23-2 so that ink is ejected from the corresponding ejection portion 600, the drive circuits 52 that generate a large amount of heat can be arranged together on the wiring board 810, and the drive circuits 52 that generate a small amount of heat can be arranged together on the wiring board 810. This reduces the risk that the structure of a heat dissipation member such as a heat sink 710 that dissipates heat from the drive circuits 52 will become complicated, and makes it possible to appropriately select whether to arrange the drive circuits 52 depending on the amount of heat generated by the multiple drive circuits 52. As a result, even when the liquid ejector 1 includes a multiple number of drive circuits 52, the heat generated by the multiple drive circuits 52 can be efficiently dissipated.

[0249] In the liquid ejection device 1 of the first embodiment, the drive circuits 52a1 and 52b1 that output the drive signals COMA1 and COMB1 supplied to the ejection module 23-1 are positioned adjacent to each other on the wiring board 810, and the drive circuits 52a2 and 52b2 that output the drive signals COMA2 and COMB2 supplied to the ejection module 23-2 are positioned adjacent to each other on the wiring board 810. This makes it possible to reduce the difference between the wiring length through which the drive signal COMA1 supplied to the ejection module 23-1 is propagated and the wiring length through which the drive signal COMB1 is propagated, and similarly, makes it possible to reduce the difference between the wiring length through which the drive signal COMA2 supplied to the ejection module 23-2 is propagated and the wiring length through which the drive signal COMB2 is propagated. As a result, the possibility of a time difference occurring due to signal propagation between the drive signals COMA1 and COMB1 for ejecting ink from the ejection module 23-1 is reduced, and similarly, the possibility of a time difference occurring due to signal propagation between the drive signals COMA2 and COMB2 for ejecting ink from the ejection module 23-2 is reduced, thereby further improving the ejection accuracy of the ink ejected from the ejection modules 23-1 and 23-2.

[0250] Furthermore, in the liquid ejection device 1 of the first embodiment, the drive circuit board 800 of the head drive module 10 includes a drive circuit 52a1 that outputs a drive signal COMA1 that drives the piezoelectric element 60 so that the ejection section 600 of the ejection module 23-1 ejects a large amount of ink, a drive circuit 52c1 that outputs a drive signal COMC1 that drives the piezoelectric element 60 so that the ejection section 600 of the ejection module 23-1 does not eject ink, a drive circuit 52a6 that outputs a drive signal COMA6 that drives the piezoelectric element 60 so that the ejection section 600 of the ejection module 23-6 ejects a large amount of ink, and a drive circuit 52c7 that outputs a drive signal COMC8 that drives the piezoelectric element 60 so that the ejection section 600 of the ejection module 23-6 does not eject ink. 6, a connection portion CN2 that electrically connects the head driving module 10 and the liquid ejection module 20, and a wiring board 810 on which the multiple driving circuits 52 and the connection portion CN2 are provided, the wiring board 810 including a wiring WA1 that propagates a driving signal COMA1 from the driving circuit 52a1 to the connection portion CN2, a wiring WC1 that propagates a driving signal COMC1 from the driving circuit 52c1 to the connection portion CN2, a wiring WA6 that propagates a driving signal COMA6 from the driving circuit 52a6 to the connection portion CN2, and a wiring WA6 that propagates a driving signal COMC6 from the driving circuit 52a6 to the connection portion CN2, and further including a multiple wiring patterns that electrically connect each of the multiple driving circuits 52 to the connection portion CN2. In such a head driving module 10, the driving circuits 52a1, 52c1, 52a6, and 52c6 are provided on the wiring board 810 so that the wiring WA1 is shorter than the wirings WC1, WA6, and WC6, and the wiring WC6 is longer than the wirings WA1, WC1, and WA6.

[0251] Here, the drive signal COMA1 drives the piezoelectric element 60 so that the ejection unit 600 of the ejection module 23-1 ejects a large amount of ink, and the drive signal COMC1 drives the piezoelectric element 60 so that the ejection unit 600 of the ejection module 23-1 does not eject ink. Therefore, the amount of current generated when the drive signal COMA1 is propagated is greater than the amount of current generated when the drive signal COMC1 is propagated. Furthermore, the drive signal COMA6 drives the piezoelectric element 60 so that the ejection unit 600 of the ejection module 23-6 ejects a large amount of ink, and the drive signal COMC6 drives the piezoelectric element 60 so that the ejection unit 600 of the ejection module 23-6 does not eject ink. Therefore, the amount of current generated when the drive signal COMA6 is propagated is greater than the amount of current generated when the drive signal COMC6 is propagated. That is, in the liquid ejection device 1 of the first embodiment, the wiring length through which a signal with a large current generated when the drive signal COM is propagated is shorter than the wiring length through which a signal with a small current generated when the signal is propagated. This reduces the influence of the impedance components of the wiring WA1, WA6 through which the drive signals COMA1, COMA propagate, which can generate a large current as they propagate. As a result, the risk of a voltage drop in the drive signals COMA1, COMA6 due to the impedance components of the wiring WA1, WA6 is reduced. That is, the waveform accuracy of the drive signals COMA1, COMA6 supplied to the liquid ejection module 20 is improved. As a result, the ink ejection accuracy of the ejection modules 23-1, 23-6 of the liquid ejection module 20 is improved.

[0252] Furthermore, in the liquid ejection device 1 of the first embodiment, in addition to the drive circuits 52a1, 52c1, 52a6, and 52c6, the head drive module 10 includes a drive circuit 52b1 that outputs a drive signal COMB1 that drives the piezoelectric element 60 so that the ejection section 600 of the ejection module 23-1 ejects a small amount of ink, and a drive circuit 52b6 that outputs a drive signal COMB6 that drives the piezoelectric element 60 so that the ejection section 600 of the ejection module 23-6 ejects a small amount of ink, and the wiring board 810 includes a wiring WB1 that propagates the drive signal COMB1 from the drive circuit 52b1 to the connection part CN2, and a wiring WB6 that propagates the drive signal COMB6 from the drive circuit 52b6 to the connection part CN2. In the head drive module 10, the drive circuit 52b1 is provided on the wiring board 810 so that the wiring WB1 is longer than the wiring WA1 and shorter than the wiring WC1, and the drive circuit 52b6 is provided on the wiring board 810 so that the wiring WB6 is longer than the wiring WA6 and shorter than the wiring WC6.

[0253] The amount of current generated when the drive signal COMB1 is propagated is smaller than the amount of current generated when the drive signal COMA1 is propagated and larger than the amount of current generated when the drive signal COMC1 is propagated, because the ejection unit 600 of the ejection module 23-1 drives the piezoelectric element 60 to eject a small amount of ink. Also, the amount of current generated when the drive signal COMB6 is propagated is smaller than the amount of current generated when the drive signal COMA6 is propagated and larger than the amount of current generated when the drive signal COMC6 is propagated, because the ejection unit 600 of the ejection module 23-6 drives the piezoelectric element 60 to eject a small amount of ink. In this head driving module 10, the driving circuit 52b1 is provided on the wiring board 810 so that the wiring WB1 is longer than the wiring WA1 and shorter than the wiring WC1, and the driving circuit 52b6 is provided on the wiring board 810 so that the wiring WB6 is longer than the wiring WA6 and shorter than the wiring WC6. This reduces the risk of a voltage drop in the driving signals COMA1 and COMA6 due to the impedance components of the wiring WA1 and WA6, even when the head driving module 10 includes the driving circuit 52b1 that outputs the driving signal COMB1 and the driving circuit 52b6 that outputs the driving signal COMB6. This reduces the risk of a voltage drop in the driving signals COMB1 and COMB6 due to the impedance components of the wiring WB1 and WB6. As a result, the ink ejection accuracy of the ejection modules 23-1 and 23-6 of the liquid ejecting module 20 is improved.

[0254] 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 assigned the same reference numerals, and their description will be simplified or omitted. In the liquid ejection device 1 according to the second embodiment, the arrangement of the multiple drive circuits 52 provided on the wiring substrate 810 differs from that of the liquid ejection device 1 according to the first embodiment.

[0255] Fig. 18 is a diagram showing an example of the configuration of a first layer 831 of a wiring substrate 810 included in a liquid ejection device 1 of the second embodiment. As shown in Fig. 18, in the liquid ejection device 1 of the second embodiment, a plurality of drive circuits 52 are located between the integrated circuit 101 and the connection part CN2, and are arranged side by side along the X2 direction.

[0256] Specifically, a drive circuit 52a1 that outputs a drive signal COMA1 for driving the piezoelectric element 60 so that a large amount of ink is ejected from the ejection module 23-1, and a drive circuit 52a2 that outputs a drive signal COMA2 for driving the piezoelectric element 60 so that a large amount of ink is ejected from the ejection module 23-2, are positioned adjacent to each other along the X2 direction, and the drive circuit 52a2 and a drive circuit 52a3 that outputs a drive signal COMA3 for driving the piezoelectric element 60 so that a large amount of ink is ejected from the ejection module 23-3, are positioned adjacent to each other along the X2 direction, and the drive circuit 52a3 and the ejection module The drive circuit 52a4 and the drive circuit 52a5 outputting a drive signal COMA5 to drive the piezoelectric element 60 so that a large amount of ink is ejected from ejection module 23-4 are positioned adjacent to each other along the X2 direction, the drive circuit 52a4 and the drive circuit 52a5 outputting a drive signal COMA5 to drive the piezoelectric element 60 so that a large amount of ink is ejected from ejection module 23-5 are positioned adjacent to each other along the X2 direction, and the drive circuit 52a5 and the drive circuit 52a6 outputting a drive signal COMA6 to drive the piezoelectric element 60 so that a large amount of ink is ejected from ejection module 23-6 are positioned adjacent to each other along the X2 direction.

[0257] Furthermore, the drive circuit 52b1 that outputs a drive signal COMB1 for driving the piezoelectric element 60 so that a small amount of ink is ejected from the ejection module 23-1 is located on the +X2 side of the drive circuit 52a6, the drive circuit 52b1 and the drive circuit 52b2 that outputs a drive signal COMB2 for driving the piezoelectric element 60 so that a small amount of ink is ejected from the ejection module 23-2 are located adjacent to each other along the X2 direction, the drive circuit 52b2 and the drive circuit 52b3 that outputs a drive signal COMB3 for driving the piezoelectric element 60 so that a small amount of ink is ejected from the ejection module 23-3 are located adjacent to each other along the X2 direction, and the drive circuit 52b3 and a drive circuit 52b4 that outputs a drive signal COMB4 to drive the piezoelectric element 60 so that a small amount of ink is ejected from the ejection module 23-4 are positioned adjacent to each other along the X2 direction, drive circuit 52b4 and a drive circuit 52b5 that outputs a drive signal COMB5 to drive the piezoelectric element 60 so that a small amount of ink is ejected from the ejection module 23-5 are positioned adjacent to each other along the X2 direction, and drive circuit 52b5 and a drive circuit 52b6 that outputs a drive signal COMB6 to drive the piezoelectric element 60 so that a small amount of ink is ejected from the ejection module 23-6 are positioned adjacent to each other along the X2 direction.

[0258] That is, in the head drive module 10, drive circuits 52a1 to 52a6 that output drive signals COMA1 to COMA6 that drive the piezoelectric element 60 to eject a large amount of ink are positioned adjacent to each other on the first layer 831 of the wiring board 810, and drive circuits 52b1 to 52b6 that output drive signals COMB1 to COMB6 that drive the piezoelectric element 60 to eject a small amount of ink are positioned adjacent to each other on the first layer 831 of the wiring board 810.

[0259] The drive circuits 52c1 to 52c6, which output drive signals COMC1 to COMC6 that drive the piezoelectric element 60 so as not to eject ink, are located closer to the side 811 of the wiring substrate 810 than the drive circuits 52b1 to 52b6, and are lined up in the order of drive circuits 52c1, 52c2, 52c3, 52c4, 52c5, and 52c6 along the X2 direction from the side 812 to the side 811.

[0260] That is, in the liquid ejector 1 of the second embodiment, the drive circuits 52a1 to 52a6, which eject a large amount of ink and therefore generate a very large amount of heat, are arranged together on the first layer 831 of the wiring board 810, the drive circuits 52b1 to 52b6, which eject a small amount of ink and therefore generate a large amount of heat, are arranged together on the first layer 831 of the wiring board 810, and the drive circuits 52c1 to 52c6, which generate an even smaller amount of heat, are arranged together on the first layer 831 of the wiring board 810. As a result, similar to the liquid ejector 1 of the first embodiment, it is possible to appropriately select whether to arrange the drive circuits 52 depending on the amount of heat generated by the large number of drive circuits 52 while reducing the risk that the structure of a heat dissipation member such as a heat sink 710 that dissipates heat from the large number of drive circuits 52 becomes complicated. As a result, even when the liquid ejector 1 is equipped with a large number of drive circuits 52, the heat generated by the large number of drive circuits 52 can be efficiently dissipated.

[0261] Next, an example of the configuration of the wiring pattern through which the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 propagate in the liquid ejection device 1 of the second embodiment will be described with reference to Figs. 19 to 21. Fig. 19 is a diagram showing an example of the wiring pattern provided on the second layer 832 of the wiring board 810 of the second embodiment. Fig. 20 is a diagram showing an example of the wiring pattern provided on the third layer 833 of the wiring board 810 of the second embodiment. Fig. 21 is a diagram showing an example of the wiring pattern provided on the fourth layer 834 of the wiring board 810 of the second embodiment.

[0262] As shown in Figure 18, in the liquid ejection device 1 of the second embodiment, the driving circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 as multiple driving circuits 52 are arranged on the first layer 831 of the wiring substrate 810 along the X2 direction from the -X2 side to the +X2 side in the order of driving circuits 52a1, 52a2, 52a3, 52a4, 52a5, 52a6, 52b1, 52b2, 52b3, 52b4, 52b5, 52b6, 52c1, 52c2, 52c3, 52c4, 52c5, and 52c6. That is, in the liquid ejection device 1 of the second embodiment, the drive circuits 52a1 to 52a6 that output drive signals COMA1 to COMA6 that drive the piezoelectric elements 60 of the ejection modules 23-1 to 23-6 so as to eject a large amount of ink from the corresponding nozzles N are located together near the connection part CN2, the drive circuits 52b1 to 52b6 that output drive signals COMB1 to COMB6 that drive the piezoelectric elements 60 of the ejection modules 23-1 to 23-6 so as to eject a small amount of ink from the corresponding nozzles N are located together farther from the connection part CN2 than the drive circuits 52a1 to 52a6, and the drive circuits 52c1 to 52c6 that output drive signals COMC1 to COMC6 that drive the piezoelectric elements 60 of the ejection modules 23-1 to 23-6 so as not to eject ink from the corresponding nozzles N are located together farther from the connection part CN2 than the drive circuits 52b1 to 52b6.

[0263] As a result, in the liquid ejection device 1 of the second embodiment, as shown in Figures 19 to 21, the wiring length of the wiring WA1 to WA6 that electrically connects each of the drive circuits 52a1 to 52a6 to the connection part CN2 and propagates the drive signals COMA1 to COMA6 can be made shorter than the wiring length of the wiring WB1 to WB6 that electrically connects each of the drive circuits 52b1 to 52b6 to the connection part CN2 and propagates the drive signals COMB1 to COMB6, and the wiring length of the wiring WA1 to WA6 and WB1 to WB6 that electrically connects each of the drive circuits 52a1 to 52a6 and 52b1 to 52b6 to the connection part CN2 and propagates the drive signals COMA1 to COMA6 and COMB1 to COMB6 can be made shorter than the wiring length of the wiring WC1 to WC6 that electrically connects each of the drive circuits 52c1 to 52c6 to the connection part CN2 and propagates the drive signals COMC1 to COMC6.

[0264] As described above, in the head driving module 10, the voltage amplitude of the driving signals COMA1 to COMA6 drives the piezoelectric element 60 so that a large amount of ink is ejected from the nozzles N of the ejection modules 23-1 to 23-6, and therefore is larger than the voltage amplitude of the driving signals COMB1 to COMB6 which drive the piezoelectric element 60 so that a small amount of ink is not ejected from the nozzles N of the ejection modules 23-1 to 23-6; and the voltage amplitude of the driving signals COMA1 to COMA6 and COMB1 to COMB6 drives the piezoelectric element 60 so that ink is ejected from the nozzles N of the ejection modules 23-1 to 23-6, and therefore is larger than the voltage amplitude of the driving signals COMC1 to COMC6 which drive the piezoelectric element 60 so that ink is not ejected from the nozzles N of the ejection modules 23-1 to 23-6.

[0265] That is, the amount of current generated by the propagation of drive signals COMA1 to COMA6 is greater than the amount of current generated by the propagation of drive signals COMB1 to COMB6 and COMC1 to COMC6, and the amount of current generated by the propagation of drive signals COMB1 to COMB6 is greater than the amount of current generated by the propagation of drive signals COMC1 to COMC6. Therefore, drive signals COMA1 to COMA6 are more susceptible to the influence of impedance generated in the wiring pattern than drive signals COMB1 to COMB6 and COMC1 to COMC6, and drive signals COMB1 to COMB6 are more susceptible to the influence of impedance generated in the wiring pattern than drive signals COMC1 to COMC6. By making the wiring length of the wiring WA1 to WA6 through which the drive signals COMA1 to COMA6 propagate, which are susceptible to the influence of impedance generated in such wiring patterns, shorter than the wiring length of the wiring WB1 to WB6 and WC1 to WC6 through which the drive signals COMB1 to COMB6 and COMC1 to COMC6 propagate, and by making the wiring length of the wiring WB1 to WB6 through which the drive signals COMB1 to COMB6 propagate shorter than the wiring length of the wiring WC1 to WC6 through which the drive signals COMC1 to COMC6 propagate, the waveform accuracy of the drive signals COMA1 to COMA6 can be further improved compared to the liquid ejection device 1 of the first embodiment.

[0266] 18, in the liquid ejection device 1 of the second embodiment, some of the plurality of through holes 820 through which screws 780 for attaching the heat sink 710 to the wiring board 810 are inserted are located between the adjacent drive circuits 52a1 and 52a2, between the adjacent drive circuits 52a2 and 52a3, between the adjacent drive circuits 52a3 and 52a4, between the adjacent drive circuits 52a4 and 52a5, The gaps are located between adjacent drive circuits 52a5 and 52a6, between adjacent drive circuits 52a6 and 52b1, between adjacent drive circuits 52b1 and 52b2, between adjacent drive circuits 52b2 and 52b3, between adjacent drive circuits 52b3 and 52b4, between adjacent drive circuits 52b4 and 52b5, and between adjacent drive circuits 52b5 and 52b6.

[0267] That is, when the heat sink 710 is attached to the wiring board 810, the screws 780 are positioned between the drive circuits 52a1-52a6 and the drive circuits 52b1-52b6 that are arranged side by side on the wiring board 810. As a result, similar to the liquid ejection device 1 of the first embodiment, heat generated in the drive circuits 52a1-52a6 and the drive circuits 52b1-52b6, which generate a large amount of heat, that is conducted to the wiring board 810 can be released to the heat sink 710 via the screws 780, thereby realizing efficient release of heat generated in the head drive module 10.

[0268] 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 of the liquid ejection device 1 according to the first and second embodiments will be denoted by the same reference numerals, and their description will be simplified or omitted. In the liquid ejection device 1 according to the third embodiment, the arrangement of the plurality of drive circuits 52 provided on the wiring substrate 810 differs from that of the liquid ejection device 1 according to the first and second embodiments. FIG. 22 is a diagram illustrating an example of the configuration of a first layer 831 of the wiring substrate 810 according to the third embodiment when viewed from the Z2 side along the Z2 direction. FIG. 23 is a diagram illustrating an example of a wiring pattern provided on a second layer 832 of the wiring substrate 810 according to the third embodiment. FIG. 24 is a diagram illustrating an example of a wiring pattern provided on a third layer 833 of the wiring substrate 810 according to the third embodiment. FIG. 25 is a diagram illustrating an example of a wiring pattern provided on a fourth layer 834 of the wiring substrate 810 according to the third embodiment.

[0269] As shown in Figure 22, in the liquid ejection device 1 of the third embodiment, the driving circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 as multiple driving circuits 52 are arranged on the first layer 831 of the wiring substrate 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, and 52c6. That is, in the liquid ejection device 1 of the third embodiment, drive circuits 52a1, 52b1, 52c1 that output drive signals COMA1, COMB1, COMC1 to drive the piezoelectric element 60 of the ejection module 23-1 are located near the connection part CN2, drive circuits 52a2, 52b2, 52c2 that output drive signals COMA2, COMB2, COMC2 to drive the piezoelectric element 60 of the ejection module 23-2 are located on the +X2 side of the drive circuits 52a1, 52b1, 52c2, and drive circuits 52a3, 52b3, 52c3 that output drive signals COMA3, COMB3, COMC3 to drive the piezoelectric element 60 of the ejection module 23-3 are located on the +X2 side of the drive circuits 52a2, 52b2, 52c2. On the +X2 side of the drive circuits 52a3, 52b3, 52c3, drive circuits 52a4, 52b4, 52c4 are located which output drive signals COMA4, COMB4, COMC4 to drive the piezoelectric element 60 of the discharge module 23-4, drive circuits 52a5, 52b5, 52c5 are located on the +X2 side of the drive circuits 52a4, 52b4, 52c4, drive circuits 52a5, 52b5, 52c5 are located which output drive signals COMA5, COMB5, COMC5 to drive the piezoelectric element 60 of the discharge module 23-5, and drive circuits 52a6, 52b6, 52c6 are located on the +X2 side of the drive circuits 52a5, 52b5, 52c5, drive circuits 52a6, 52b6, 52c6 are located which output drive signals COMA6, COMB6, COMC6 to drive the piezoelectric element 60 of the discharge module 23-6.

[0270] As a result, as shown in Figures 23 to 25, the wiring length of wiring WA1, which electrically connects drive circuit 52a1 and connection part CN2 and propagates drive signal COMA1, can be made shorter than the wiring length of wiring WB1, which electrically connects drive circuit 52b1 and connection part CN2 and propagates drive signal COMB1, and the wiring length of wiring WA1, WB1 can be made shorter than the wiring length of wiring WC1, which electrically connects drive circuit 52c1 and connection part CN2 and propagates drive signal COMC1.

[0271] Similarly, the wiring length of wiring WA2, which electrically connects drive circuit 52a2 and connection part CN2 and propagates drive signal COMA2, can be made shorter than the wiring length of wiring WB2, which electrically connects drive circuit 52b2 and connection part CN2 and propagates drive signal COMB2, and the wiring length of wiring WA2, WB2 can be made shorter than the wiring length of wiring WC2, which electrically connects drive circuit 52c2 and connection part CN2 and propagates drive signal COMC2.

[0272] Similarly, the wiring length of wiring WA3, which electrically connects drive circuit 52a3 and connection part CN2 and propagates drive signal COMA3, can be made shorter than the wiring length of wiring WB3, which electrically connects drive circuit 52b3 and connection part CN2 and propagates drive signal COMB3, and the wiring length of wiring WA3, WB3 can be made shorter than the wiring length of wiring WC3, which electrically connects drive circuit 52c3 and connection part CN2 and propagates drive signal COMC3.

[0273] Similarly, the wiring length of wiring WA4, which electrically connects drive circuit 52a4 and connection part CN2 and propagates drive signal COMA4, can be made shorter than the wiring length of wiring WB4, which electrically connects drive circuit 52b4 and connection part CN2 and propagates drive signal COMB4, and the wiring length of wiring WA4, WB4 can be made shorter than the wiring length of wiring WC4, which electrically connects drive circuit 52c4 and connection part CN2 and propagates drive signal COMC4.

[0274] Similarly, the wiring length of wiring WA5, which electrically connects drive circuit 52a5 and connection part CN2 and propagates drive signal COMA5, can be made shorter than the wiring length of wiring WB5, which electrically connects drive circuit 52b5 and connection part CN2 and propagates drive signal COMB5, and the wiring length of wiring WA5, WB5 can be made shorter than the wiring length of wiring WC5, which electrically connects drive circuit 52c5 and connection part CN2 and propagates drive signal COMC5.

[0275] Similarly, the wiring length of wiring WA6, which electrically connects drive circuit 52a6 and connection part CN2 and propagates drive signal COMA6, can be made shorter than the wiring length of wiring WB6, which electrically connects drive circuit 52b6 and connection part CN2 and propagates drive signal COMB6, and the wiring length of wiring WA6, WB6 can be made shorter than the wiring length of wiring WC6, which electrically connects drive circuit 52c6 and connection part CN2 and propagates drive signal COMC6.

[0276] As a result, for each ejection module 23, the wiring length of the wiring WA1 to WA6 through which the drive signals COMA1 to COMA6 propagate, which are susceptible to the influence of impedance generated in the wiring pattern, can be made shorter than the wiring length of the wiring WB1 to WB6 and WC1 to WC6 through which the drive signals COMB1 to COMB6 and COMC1 to COMC6 propagate, and the wiring length of the wiring WB1 to WB6 through which the drive signals COMB1 to COMB6 propagate can be made shorter than the wiring length of the wiring WC1 to WC6 through which the drive signals COMC1 to COMC6 propagate, thereby improving the ink ejection accuracy for each ejection module 23.

[0277] Furthermore, in the liquid ejection device 1 of the third embodiment, the difference in length between the wiring length of the wiring WA1 that supplies the drive signal COMA1 to the ejection module 23-1, the wiring length of the wiring WB1 that supplies the drive signal COMB1, and the wiring length of the wiring WC1 that supplies the drive signal COMC1 can be reduced, thereby reducing supply errors that may occur due to differences in the wiring lengths of the drive signals COMA1, COMB1, and COMC1 supplied to the ejection module 23-1.

[0278] Similarly, the difference in length between the wiring length of the wiring WA2 that supplies the drive signal COMA2 to the discharge module 23-2, the wiring length of the wiring WB2 that supplies the drive signal COMB2, and the wiring length of the wiring WC2 that supplies the drive signal COMC2 can be reduced, and the difference in length between the wiring length of the wiring WA3 that supplies the drive signal COMA3 to the discharge module 23-3, the wiring length of the wiring WB3 that supplies the drive signal COMB3, and the wiring length of the wiring WC3 that supplies the drive signal COMC3 can be reduced, and the difference in length between the wiring length of the wiring WA4 that supplies the drive signal COMA4 to the discharge module 23-4, and the wiring length of the wiring WB2 that supplies the drive signal COMB4 to the discharge module 23-5 can be reduced. It is possible to reduce the difference in length between the wiring length of the wiring WB4 that supplies the drive signal COMC4 to the discharge module 23-5 and the wiring length of the wiring WC4 that supplies the drive signal COMC4, it is possible to reduce the difference in length between the wiring length of the wiring WA5 that supplies the drive signal COMA5 to the discharge module 23-5, the wiring length of the wiring WB5 that supplies the drive signal COMB5, and the wiring length of the wiring WC5 that supplies the drive signal COMC5, it is possible to reduce the difference in length between the wiring length of the wiring WA6 that supplies the drive signal COMA6 to the discharge module 23-6, the wiring length of the wiring WB6 that supplies the drive signal COMB6, and the wiring length of the wiring WC6 that supplies the drive signal COMC6.

[0279] This reduces the possibility that timing differences due to wiring length will occur in the signals input to the ejection modules 23-1 to 23-6, and improves the ink ejection accuracy for each ejection module 23.

[0280] Also, as shown in Figure 22, in the liquid ejection device 1 of the third embodiment, some of the multiple through holes 820 through which screws 780 for attaching the heat sink 710 to the wiring board 810 are inserted are located between adjacent drive circuits 52a1 and 52b1, between adjacent drive circuits 52a2 and 52b2, between adjacent drive circuits 52a3 and 52b3, between adjacent drive circuits 52a4 and 52b4, between adjacent drive circuits 52a5 and 52b5, and between adjacent drive circuits 52a6 and 52b6.

[0281] That is, in the liquid ejection device 1 of the third embodiment, the drive circuits 52a1 to 52a6, the drive circuits 52b1 to 52b6, and the drive circuits 52c1 to 52c6 are arranged on the wiring substrate 810 in the X2 direction in the order of drive circuits 52a1, 52b1, 52c1, 52a2, 52b2, 52c2, 52a3, 52b3, 52c3, 52a4, 52b4, 52c4, 52a5, 52b5, 52c5, 52a6, 52b6, 52c6. The through holes 820 through which the screws 780 for attaching the heat sink 710 to the wiring board 810 are inserted are located in the X2 direction between the drive circuits 52a1 and 52b1, between the drive circuits 52a2 and 52b2, between the drive circuits 52a3 and 52b3, between the drive circuits 52a4 and 52b4, between the drive circuits 52a5 and 52b5, and between the drive circuits 52a6 and 52b6.

[0282] Even in the liquid ejection device 1 of the third embodiment configured as described above, like the liquid ejection devices 1 of the first and second embodiments, the heat generated in the drive circuits 52a1 to 52a6 and drive circuits 52b1 to 52b6, which have a large amount of heat, and conducted to the wiring board 810 can be released to the heat sink 710 via the screws 780, thereby realizing efficient release of the heat generated in the head drive module 10.

[0283] 26, in the liquid ejection device 1 of the third embodiment, a plurality of through holes 820 through which screws 780 for attaching the heat sink 710 to the wiring board 810 are inserted may be further provided along the X2 direction between the drive circuits 52c1 and 52a2, between the drive circuits 52c2 and 52a3, between the drive circuits 52c3 and 52a4, between the drive circuits 52c4 and 52a5, and between the drive circuits 52c5 and 52a6. Figure 26 is a diagram showing an example of the configuration of a first layer 831 of the wiring board 810 of the modified example of the third embodiment when viewed from the Z2 side along the Z2 direction.

[0284] In the liquid ejection device 1 in the modified example of the third embodiment configured as described above, the heat generated in the drive circuits 52a1 to 52a6, which generate particularly large amounts of heat, is conducted to the wiring board 810 and can be dissipated to the heat sink 710 via the two screws 780, thereby further improving the efficiency of dissipating heat generated in the head drive module 10.

[0285] 22 and 26, among the multiple through holes 820 provided in the wiring substrate 810, the through hole 820 located between drive circuits 52a1 and 52b1 is an example of a first through hole, the through hole 820 located between drive circuits 52a2 and 52b2 is an example of a second through hole, and the through hole 820 located between drive circuits 52c1 and 52a2 is an example of a third through hole. Furthermore, the screw 780 inserted through the through hole 820 corresponding to the first through hole is an example of a first screw, the screw 780 inserted through the through hole 820 corresponding to the second through hole is an example of a second screw, and the screw 780 inserted through the through hole 820 corresponding to the third through hole is an example of a third screw.

[0286] 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.

[0287] 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.

[0288] The following can be derived from the above-described embodiment.

[0289] One aspect of the liquid ejection device is a discharge head that discharges liquid in response to driving of a first piezoelectric element; a substrate having a first through hole; a first drive circuit, a second drive circuit, and a third drive circuit provided on the substrate; a metal frame attached to the substrate; a first screw that passes through the first through hole and attaches the metal frame to the substrate; Equipped with the first drive circuit outputs a first drive signal that drives the first piezoelectric element so that the ejection head ejects a first ejection amount of liquid; the second drive circuit outputs a second drive signal that drives the first piezoelectric element so that the ejection head ejects a second amount of liquid; the third drive circuit outputs a third drive signal that drives the first piezoelectric element so as not to cause the ejection head to eject liquid; the first drive circuit, the second drive circuit, and the third drive circuit are arranged side by side in one direction on the substrate in the order of the first drive circuit, the second drive circuit, and the third drive circuit; The first through hole is located between the first drive circuit and the second drive circuit in the one direction.

[0290] In this liquid ejection device, the first screw attaches a metal frame to the substrate between the first drive circuit, which generates a large amount of heat because it outputs a first drive signal that drives the first piezoelectric element so that the ejection head ejects a first amount of liquid, and the second drive circuit, which generates a large amount of heat because it outputs a second drive signal that drives the first piezoelectric element so that the ejection head ejects a second amount of liquid, so that the first drive circuit can conduct some of the heat generated in the first drive circuit and the second drive circuit to the heat sink via the first screw.This improves the efficiency of conduction of heat generated in the first drive circuit and the second drive circuit to the metal frame, and improves the efficiency of heat dissipation from the first drive circuit and the second drive circuit by the metal frame.

[0291] In one aspect of the liquid ejection device, the ejection head includes a second piezoelectric element, a fourth drive circuit, a fifth drive circuit, and a sixth drive circuit provided on the substrate; the fourth drive circuit outputs a fourth drive signal that drives the second piezoelectric element so that the ejection head ejects a third ejection amount of liquid; the fifth drive circuit outputs a fifth drive signal that drives the second piezoelectric element so that the ejection head ejects a fourth ejection amount of liquid; The sixth drive circuit may output a sixth drive signal that drives the second piezoelectric element so as to prevent the ejection head from ejecting liquid.

[0292] According to this liquid ejection device, even when it has a fourth drive circuit that outputs a fourth drive signal supplied to the second piezoelectric element, a fifth drive circuit that outputs a fifth drive signal, and a sixth drive circuit that outputs a sixth drive signal, the efficiency of heat conduction to the metal frame is improved, so efficient heat dissipation through the metal frame can be achieved.

[0293] In one aspect of the liquid ejection device, The first drive circuit, the second drive circuit, the third drive circuit, the fourth drive circuit, the fifth drive circuit, and the sixth drive circuit may be arranged in the same direction on the substrate in the order of the first drive circuit, the second drive circuit, the third drive circuit, the fourth drive circuit, the fifth drive circuit, and the sixth drive circuit.

[0294] In one aspect of the liquid ejection device, the substrate has a second through hole; a second screw that passes through the second through hole and attaches the metal frame to the substrate; The second through hole may be located between the fourth drive circuit and the fifth drive circuit in the one direction.

[0295] According to this liquid ejection device, the second screw attaches the metal frame to the substrate between the fourth drive circuit, which generates a large amount of heat because it outputs a fourth drive signal that drives the second piezoelectric element so that the ejection head ejects the third amount of liquid, and the fifth drive circuit, which generates a large amount of heat because it outputs a fifth drive signal that drives the second piezoelectric element so that the ejection head ejects the fourth amount of liquid, so that the second drive circuit can conduct some of the heat generated in the fourth drive circuit and the fifth drive circuit to the heat sink via the second screw.This improves the efficiency of conduction of heat generated in the fourth drive circuit and the fifth drive circuit to the metal frame, and improves the efficiency of heat dissipation from the fourth drive circuit and the fifth drive circuit by the metal frame.

[0296] In one aspect of the liquid ejection device, the substrate has a third through hole; a third screw that is inserted through the third through hole and attaches the metal frame to the substrate; The third through hole may be located between the third drive circuit and the fourth drive circuit in the one direction.

[0297] In this liquid ejection device, the second and third screws attach the metal frame to the substrate on both sides of the fourth drive circuit, allowing some of the heat generated in the fourth drive circuit to be conducted to the heat sink via the second and third screws, further improving the efficiency of conduction of heat generated in the fourth drive circuit to the metal frame and further improving the efficiency of heat dissipation from the fourth drive circuit by the metal frame.

[0298] In one aspect of the liquid ejection device, the substrate has a fourth through hole and a fifth through hole; a fourth screw that is inserted through the fourth through hole and attaches the metal frame to the substrate; a fifth screw that is inserted through the fifth through hole and attaches the metal frame to the substrate; Equipped with the first drive circuit, the second drive circuit, the third drive circuit, the fourth drive circuit, the fifth drive circuit, and the sixth drive circuit are arranged side by side on the substrate in the one direction in this order: the first drive circuit, the second drive circuit, the fourth drive circuit, the fifth drive circuit, the third drive circuit, and the sixth drive circuit; the fourth through hole is located between the second drive circuit and the fourth drive circuit in the one direction, The fifth through hole may be located between the fourth drive circuit and the fifth drive circuit in the one direction.

[0299] According to this liquid ejection device, a first drive circuit that outputs a first drive signal to drive the first piezoelectric element so that the ejection head ejects liquid, a second drive circuit that outputs a second drive signal to drive the first piezoelectric element so that the ejection head ejects liquid, a fourth drive circuit that outputs a fourth drive signal to drive the second piezoelectric element so that the ejection head ejects liquid, and a fifth drive circuit that outputs a fifth drive signal to drive the second piezoelectric element so that the ejection head ejects liquid are all positioned together on the substrate, and a third drive circuit that outputs a third drive signal to drive the first piezoelectric element so that the ejection head does not eject liquid, and a fifth drive circuit that outputs a fifth drive signal to drive the second piezoelectric element so that the ejection head does not eject liquid. and the sixth drive circuit that outputs a sixth drive signal that drives the second piezoelectric element are positioned together on the substrate, and a first screw attaches the metal frame to the substrate between the first drive circuit and the second drive circuit, a fourth screw attaches the metal frame to the substrate between the second drive circuit and the fourth drive circuit, and a fifth screw attaches the metal frame to the substrate between the fourth drive circuit and the fifth drive circuit, so that heat generated in the first drive circuit, second drive circuit, fourth drive circuit, and fifth drive circuit, which generate more heat than the third drive circuit and the sixth drive circuit, can be conducted to the heat sink more efficiently via the first screw, fourth screw, and fifth screw. This further improves the heat dissipation efficiency of the metal frames of the first drive circuit, second drive circuit, fourth drive circuit, and fifth drive circuit.

[0300] In one aspect of the liquid ejection device, The first drive circuit may include a surface-mounted transistor.

[0301] According to this liquid ejection device, even if a portion of the heat generated in the first drive circuit is conducted to the substrate, the heat conducted to the substrate via the first screw can be conducted to the metal frame. Therefore, even if the first drive circuit includes a surface-mounted transistor that conducts a large amount of heat to the substrate, the heat generated in the first drive circuit can be conducted to the heat sink more efficiently via the first screw.

[0302] In one aspect of the liquid ejection device, The metal frame may be a heat sink that dissipates heat from at least one of the first drive circuit, the second drive circuit, and the third drive circuit.

[0303] According to this liquid ejection device, the metal frame is configured as a heat sink for the purpose of heat dissipation, which further improves the efficiency of dissipating heat generated in the first drive circuit and the second drive circuit.

[0304] One aspect of the head drive circuit is a head drive circuit that drives a discharge head that discharges liquid in response to driving of a first piezoelectric element, a substrate having a first through hole; a first drive circuit, a second drive circuit, and a third drive circuit provided on the substrate; a metal frame attached to the substrate; a first screw that passes through the first through hole and attaches the metal frame to the substrate; Equipped with the first drive circuit outputs a first drive signal that drives the first piezoelectric element so that the ejection head ejects a first ejection amount of liquid; the second drive circuit outputs a second drive signal that drives the first piezoelectric element so that the ejection head ejects a second amount of liquid; the third drive circuit outputs a third drive signal that drives the first piezoelectric element so as not to cause the ejection head to eject liquid; the first drive circuit, the second drive circuit, and the third drive circuit are arranged side by side in one direction on the substrate in the order of the first drive circuit, the second drive circuit, and the third drive circuit; The first through hole is located between the first drive circuit and the second drive circuit in the one direction.

[0305] According to this head drive circuit, the first drive circuit generates a large amount of heat because it outputs a first drive signal that drives the first piezoelectric element to eject a first amount of liquid from the ejection head, and the second drive circuit generates a large amount of heat because it outputs a second drive signal that drives the first piezoelectric element to eject a second amount of liquid from the ejection head, and by attaching the metal frame to the substrate with the first screw, some of the heat generated in the first drive circuit and the second drive circuit can be conducted to the heat sink via the first screw. This improves the efficiency of conduction of heat generated in the first drive circuit and the second drive circuit to the metal frame, and improves the efficiency of heat dissipation from the first drive circuit and the second drive circuit by the metal frame. [Explanation of symbols]

[0306] 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...wiring 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, 50-1 to 50-j...drive signal output circuit, 52, 52a, 52b, 52c...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, 210...selection control circuit, 212...shift register, 214...latch circuit, 216...decoder, 220...restoration circuit, 230...selection circuit, 232a, 232b, 232c...inverters, 234a, 234b, 234c...transfer gates, 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 circuit, 512, 513...adder, 514...comparator, 515...inverter, 516...integral attenuator, 517...attenuator, 520...gate drive circuit, 521, 522...gate driver, 550...amplifier circuit, 560...demodulation circuit, 570, 572...feedback circuit, 590...power supply circuit, 600...discharge portion, 610...diaphragm, 611...lead electrode, 620...compliance substrate, 621...sealing film, 622...fixed substrate, 623...nozzle plate, 623a...liquid ejection surface, 630...communicating plate, 641...protective substrate, 642...flow path forming substrate, 643...through hole, 644...protective cavity Between, 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...first layer, 832...second layer, 833...third layer, 834...fourth layer, 835...fifth layer, 840...insulating layer, C1-C5...capacitor, CB...pressure chamber, CN1,CN2...connection part, 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, Su1, Su2...flow path plate, WA1 to WA6, WB1 to WB6, WC1 to WC6...wiring,

Claims

1. a discharge head having a first discharge module that discharges liquid in response to driving of a first piezoelectric element; a substrate having a first through hole; a first drive circuit, a second drive circuit, and a third drive circuit provided on the substrate; a metal frame attached to the substrate; a first screw that passes through the first through hole and attaches the metal frame to the substrate; Equipped with the first drive circuit outputs a first drive signal that drives the first piezoelectric element so that the ejection head ejects a first ejection amount of liquid; the second drive circuit outputs a second drive signal that drives the first piezoelectric element so that the ejection head ejects a second amount of liquid; the third drive circuit outputs a third drive signal that drives the first piezoelectric element so as not to cause the ejection head to eject liquid; the first drive circuit, the second drive circuit, and the third drive circuit are arranged side by side in one direction on the substrate in this order; the first through hole is located between the first drive circuit and the second drive circuit in the one direction; A liquid ejection device characterized by:

2. the ejection head includes a second ejection module that ejects liquid in response to driving of a second piezoelectric element; a fourth drive circuit, a fifth drive circuit, and a sixth drive circuit provided on the substrate; the fourth drive circuit outputs a fourth drive signal that drives the second piezoelectric element so that the ejection head ejects a third ejection amount of liquid; the fifth drive circuit outputs a fifth drive signal that drives the second piezoelectric element so that the ejection head ejects a fourth ejection amount of liquid; the sixth drive circuit outputs a sixth drive signal that drives the second piezoelectric element so as not to cause the ejection head to eject liquid; The liquid ejection device according to claim 1 .

3. the first drive circuit, the second drive circuit, the third drive circuit, the fourth drive circuit, the fifth drive circuit, and the sixth drive circuit are arranged on the substrate in the one direction in this order: the first drive circuit, the second drive circuit, the third drive circuit, the fourth drive circuit, the fifth drive circuit, and the sixth drive circuit; 3. The liquid ejection device according to claim 2.

4. the substrate has a second through hole; a second screw that passes through the second through hole and attaches the metal frame to the substrate; the second through hole is located between the fourth drive circuit and the fifth drive circuit in the one direction; 4. The liquid ejection device according to claim 3.

5. the substrate has a third through hole; a third screw that is inserted through the third through hole and attaches the metal frame to the substrate; the third through hole is located between the third drive circuit and the fourth drive circuit in the one direction; 5. The liquid ejection device according to claim 3 or 4.

6. the substrate has a fourth through hole and a fifth through hole; a fourth screw that is inserted through the fourth through hole and attaches the metal frame to the substrate; a fifth screw that is inserted through the fifth through hole and attaches the metal frame to the substrate; Equipped with the first drive circuit, the second drive circuit, the third drive circuit, the fourth drive circuit, the fifth drive circuit, and the sixth drive circuit are arranged on the substrate in the one direction in this order: the first drive circuit, the second drive circuit, the fourth drive circuit, the fifth drive circuit, the third drive circuit, and the sixth drive circuit; the fourth through hole is located between the second drive circuit and the fourth drive circuit in the one direction, the fifth through hole is located between the fourth drive circuit and the fifth drive circuit in the one direction; 3. The liquid ejection device according to claim 2.

7. the first drive circuit includes a surface-mounted transistor; 7. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

8. the metal frame is a heat sink that dissipates heat from at least one of the first drive circuit, the second drive circuit, and the third drive circuit.

8. The liquid ejection device according to claim 1, wherein the liquid ejection device is a liquid ejection device.

9. a head drive circuit that drives a discharge head that discharges liquid in response to driving of a first piezoelectric element, a substrate having a first through hole; a first drive circuit, a second drive circuit, and a third drive circuit provided on the substrate; a metal frame attached to the substrate; a first screw that passes through the first through hole and attaches the metal frame to the substrate; Equipped with the first drive circuit outputs a first drive signal that drives the first piezoelectric element so that the ejection head ejects a first ejection amount of liquid; the second drive circuit outputs a second drive signal that drives the first piezoelectric element so that the ejection head ejects a second amount of liquid; the third drive circuit outputs a third drive signal that drives the first piezoelectric element so as not to cause the ejection head to eject liquid; the first drive circuit, the second drive circuit, and the third drive circuit are arranged side by side in one direction on the substrate in this order; The first through hole is located between the first drive circuit and the second drive circuit in the one direction. Located A head drive circuit comprising:

Images