Liquid ejection device and head drive circuit

Abstract

To provide a liquid discharge device that can radiate heat generated in a number of driving circuits efficiently.SOLUTION: A liquid discharge device comprises: a first discharge part that discharges liquid in response to driving of a first piezoelectric element; a second discharge part that discharges liquid in response to driving of a second piezoelectric element; a substrate; a first driving circuit that outputs a first driving signal for driving the first piezoelectric element so that the first discharge part discharges a first discharge amount of liquid; a second driving circuit that outputs a second driving signal for driving the first piezoelectric element so that the first discharge part does not discharge liquid; a third driving circuit that outputs a third driving signal for driving the second piezoelectric element so that the second discharge part discharges a second discharge amount of liquid; and a fourth driving circuit that outputs a fourth driving signal for driving the second piezoelectric element so that the second discharge part does not discharge liquid. The third driving circuit is positioned, along one direction, between the first driving circuit and the second driving circuit. The shortest distance between the fourth driving circuit and the second driving circuit is shorter than the shortest distance between the fourth driving circuit and the third driving circuit.SELECTED DRAWING: Figure 14

Description

Technical Field

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

Background Art

[0002] A liquid ejection device that forms an image or a document on a medium by ejecting ink as a liquid has drive elements provided corresponding to each of a plurality of nozzles that eject the liquid. When the drive elements are driven, ink is ejected from the corresponding nozzles, and such a configuration is known. The drive elements used in such a liquid ejection device are provided corresponding to each of the plurality of nozzles. Therefore, the drive circuit needs to output a drive signal including sufficient current to drive a plurality of drive elements simultaneously. In particular, in a liquid ejection device using a piezoelectric element as a drive element, since the piezoelectric element is a capacitive load like a capacitor electrically, it is necessary to supply sufficient current to the piezoelectric element from the viewpoint of accurately driving the piezoelectric element.

[0003] However, since the drive circuit for driving the drive elements outputs a drive signal including a large current, it generates a large amount of heat. If the heat generated in such a drive circuit contributes to the liquid to be ejected, the physical properties of the liquid may change. Also, if the heat generated in the drive circuit contributes to the electronic components included in the drive circuit, the characteristics of the electronic components may change. That is, the heat generated in the drive circuit may reduce the stability of the operation of the drive circuit and may also reduce the liquid ejection characteristics in the liquid ejection device by changing the physical properties of the liquid. Therefore, various heat dissipation structures for efficiently releasing the heat of the drive circuit have been studied in liquid ejection devices.

[0004] For example, Patent Document 1 discloses a liquid ejection device in which a circuit board on which a plurality of drive circuits that output drive signals for driving a piezoelectric element as a drive element are arranged is housed in a case, and among the plurality of drive circuits, a drive circuit with a large heat generation amount is arranged near the intake port of the case, thereby enhancing the heat dissipation efficiency of the drive circuit and enhancing the operating stability of the drive circuit.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In response to the market demand for higher image formation speeds in recent liquid ejection devices, the number of nozzles of the liquid ejection device has increased, and as a result, the number of drive elements for ejecting liquid from the nozzles has also increased. Such an increase in the number of drive elements leads to an increase in the output current of the drive circuit that outputs the drive signal for driving the drive element, and as a result, there is a risk of increasing the heat generation of the drive circuit. In addition, an increase in the number of drive elements of the liquid ejection device also increases the number of drive circuits that output drive signals for driving the drive elements. That is, in response to the market demand for higher image formation speeds in recent years, the liquid ejection device is required to efficiently dissipate heat from a large number of drive circuits that generate a large amount of heat. However, from the perspective of efficiently dissipating heat from a large number of drive circuits, the heat dissipation method described in Patent Document 1 is not sufficient and there is room for improvement.

Means for Solving the Problems

[0007] One aspect of the liquid ejection device according to the present invention is a first ejection unit group including a first ejection unit that includes a first piezoelectric element and ejects liquid in response to driving of the first piezoelectric element, and a second ejection unit group including a second ejection unit that includes a second piezoelectric element and ejects liquid in response to driving of the second piezoelectric element, and a discharge head having the same; a substrate, a first drive circuit, a second drive circuit, a third drive circuit, and a fourth drive circuit provided side by side along one direction of the substrate, and is provided with, the first drive circuit outputs a first drive signal for driving the first piezoelectric element so that the first discharge portion discharges a liquid of a first discharge amount, the second drive circuit outputs a second drive signal for driving the first piezoelectric element so that the first discharge portion does not discharge a liquid, the third drive circuit outputs a third drive signal for driving the second piezoelectric element so that the second discharge portion discharges a liquid of a second discharge amount, the fourth drive circuit outputs a fourth drive signal for driving the second piezoelectric element so that the second discharge portion does not discharge a liquid, the third drive circuit is located between the first drive circuit and the second drive circuit along the one direction, the shortest distance between the fourth drive circuit and the second drive circuit is shorter than the shortest distance between the fourth drive circuit and the third drive circuit.

[0008] One aspect of the head drive circuit according to the present invention is, a head drive circuit for driving a discharge head having a first discharge portion group including a first piezoelectric element and including a first discharge portion that discharges a liquid according to driving of the first piezoelectric element, and a second discharge portion group including a second piezoelectric element and including a second discharge portion that discharges a liquid according to driving of the second piezoelectric element, a substrate, a first drive circuit, a second drive circuit, a third drive circuit, and a fourth drive circuit provided side by side along one direction of the substrate, and is provided with, the first drive circuit outputs a first drive signal for driving the first piezoelectric element so that the first discharge portion discharges a liquid of a first discharge amount, the second drive circuit outputs a second drive signal for driving the first piezoelectric element so that the first discharge portion does not discharge a liquid, the third drive circuit outputs a third drive signal for driving the second piezoelectric element so that the second discharge portion discharges a liquid of a second discharge amount, The fourth drive circuit outputs a fourth drive signal for driving the second piezoelectric element so that the second discharge unit does not discharge liquid. The third drive circuit is located between the first drive circuit and the second drive circuit along the one direction. The shortest distance between the fourth drive circuit and the second drive circuit is shorter than the shortest distance between the fourth drive circuit and the third drive circuit.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The drawings used are for convenience of explanation. Note that the embodiments described below do not unduly limit the content of the present invention described in the claims. Also, not all of the configurations described below are essential constituent elements of the present invention.

[0011] 1. First Embodiment 1.1 Configuration of the Liquid Discharge 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 conveyed by a conveyance unit 4. Here, in the following description, the direction in which the medium P is conveyed may be referred to as the conveyance direction, and the width direction of the conveyed medium P may 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 conveyance unit 4, and a plurality of ejection units 5.

[0013] The control unit 2 includes a processing circuit such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and a storage circuit such as a semiconductor memory. The control unit 2 outputs a signal for controlling 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 the liquid supplied to the ejection unit 5. Specifically, the liquid container 3 stores inks of a plurality of colors ejected onto the medium P, such as, for example, black, cyan, magenta, yellow, red, gray, and the like.

[0015] The conveyance unit 4 has a conveyance motor 41 and conveyance rollers 42. A conveyance control signal Ctrl-T output by the control unit 2 is input to the conveyance unit 4. Then, when the conveyance motor 41 operates based on the input conveyance control signal Ctrl-T, and the conveyance rollers 42 are rotationally driven along with the operation of the conveyance motor 41, the medium P is conveyed along the conveyance direction.

[0016] The plurality of ejection units 5 each have a head drive 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 thereto. Then, based on the image information signal IP input from the control unit 2, the head drive module 10 controls the operation of the liquid ejection module 20, and in accordance with the control of the head drive module 10, the liquid ejection module 20 ejects the ink supplied from the liquid container 3 onto the medium P.

[0017] In the liquid ejection device 1 according to the first embodiment, the liquid ejection modules 20 each included in the plurality of ejection units 5 are arranged side by side along the main scanning direction so as to have a width equal to or greater than the width of the medium P, thereby constituting a so-called line-type inkjet printer capable of ejecting ink onto the entire area in the width direction of the conveyed medium P. Note that the liquid ejection device 1 is not limited to a line-type inkjet printer.

[0018] Next, the schematic configuration of the ejection unit 5 will be described. FIG. 2 is a diagram showing the schematic configuration of the ejection unit 5. As shown in FIG. 2, the ejection unit 5 has a head drive module 10 and a liquid ejection module 20. Also, in the ejection unit 5, the head drive module 10 and the liquid ejection module 20 are electrically connected by a wiring member 30.

[0019] The wiring member 30 is a flexible member for electrically connecting the head drive 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 drive module 10 and the liquid ejection module 20 may be electrically connected without having an FPC or an FFC, for example, by a board-to-board (BtoB) connector, or may be electrically connected by using a combination of a BtoB connector and an FPC or an FFC.

[0020] The head drive module 10 includes a control circuit 100, drive 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 from the control unit 2 is input to the control circuit 100. The control circuit 100 outputs a signal for controlling each element of the ejection 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 it to the conversion circuit 120. The conversion circuit 120 converts the base data signal dDATA into a differential signal such as LVDS (Low Voltage Differential Signaling), and outputs it to the liquid ejection module 20 as a data signal DATA. Note that the conversion circuit 120 may convert the base data signal dDATA into a differential signal of a high-speed transfer method such as LVPECL (Low Voltage Positive Emitter Coupled Logic) or CML (Current Mode Logic) other than LVDS, and output it to the liquid ejection module 20 as the data signal DATA. Also, a part or all of the input base data signal dDATA may be output to the liquid ejection module 20 as a single-ended data signal DATA.

[0023] Further, the control circuit 100 outputs base drive signals dA1, dB1, and dC1 to the drive signal output circuit 50-1. The drive signal output circuit 50-1 includes drive circuits 52a, 52b, and 52c. The base drive signal dA1 is input to the drive circuit 52a. The drive circuit 52a digitally / analog-converts the input base drive signal dA1 and then generates a drive signal COMA1 by Class-D amplification and outputs it to the liquid ejection module 20. The base drive signal dB1 is input to the drive circuit 52b. The drive circuit 52b digitally / analog-converts the input base drive signal dB1 and then generates a drive signal COMB1 by Class-D amplification and outputs it to the liquid ejection module 20. The base drive signal dC1 is input to the drive circuit 52c. The drive circuit 52c digitally / analog-converts the input base drive signal dC1 and then generates a drive signal COMC1 by Class-D amplification and outputs it to the liquid ejection module 20.

[0024] Here, each of the drive circuits 52a, 52b, and 52c only needs to be able to generate the drive signals COMA1, COMB1, and COMC1 by amplifying the waveforms defined by the respective input base drive signals dA1, dB1, and dC1. Instead of or in addition to the Class-D amplification circuit, it may include a Class-A amplification circuit, a Class-B amplification circuit, or a Class-AB amplification circuit, etc. Also, each of the base drive signals dA1, dB1, and dC1 only needs to be able to define the waveforms of the corresponding drive signals COMA1, COMB1, and COMC1 and may be an analog signal.

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

[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 input and output signals are different. That is, each of the drive signal output circuits 50-j (j is any one of 1 to m) includes circuits corresponding to the drive circuits 52a, 52b, and 52c, respectively, and a circuit corresponding to the reference voltage output circuit 53. Based on the basic drive signals dAj, dBj, and dCj input from the control circuit 100, the drive signals COMAj, COMBj, and COMCj and the reference voltage signal VBSj are generated and output 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. When there is no need to distinguish in the following description, they may simply be referred to as the drive circuit 52. In this case, the drive circuit 52 will be described as generating the drive signal COM based on the basic drive signal do and outputting it to the liquid ejection module 20. Also, when distinguishing and describing 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 ejection modules 23-1 to 23-m, respectively, and outputs it to the corresponding ejection 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 differential signal data signal DATA output by the head drive module 10 to a single-ended signal, and separates and outputs the restored signal to signals corresponding to the ejection modules 23-1 to 23-m. Thereby, 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 one 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 to SCKm, the print data signals SI1 to SIm, and the latch signals LAT1 to LATm, the data signal DATA output by the control circuit 100 is a differential signal corresponding to the clock signals SCK1 to SCKm, the print data signals SI1 to SIm, and the latch signals LAT1 to LATm. Also, the base data signal dDATA that serves as the basis of the data signal DATA includes signals corresponding to each of the clock signals SCK1 to SCKm, the print data signals SI1 to SIm, and the latch signals LAT1 to LATm. That is, the control circuit 100 outputs the base data signal dDATA as a signal for controlling the operations of the discharge modules 23-1 to 23-m included in the liquid discharge module 20.

[0033] The discharge module 23-1 includes 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 the same number of piezoelectric elements 60 as the plurality of discharge units 600.

[0034] The drive signals COMA1, COMB1, COMC1, the reference voltage signal VBS1, the clock signal SCK1, the print data signal SI1, and the latch signal LAT1 are input to the discharge module 23-1. The drive signals COMA1, COMB1, COMC1, the clock signal SCK1, the print data signal SI1, and the latch signal LAT1 are input to the drive signal selection circuit 200 included in the discharge module 23-1. The drive signal selection circuit 200 generates a drive signal VOUT by selecting or not selecting each of the drive signals COMA1, COMB1, COMC1 based on the input clock signal SCK1, print data signal SI1, and latch signal LAT1, and supplies it to one end of the piezoelectric element 60 included in the corresponding discharge unit 600. At this time, the reference voltage signal VBS1 is supplied to the other end of the piezoelectric element 60. Then, 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 discharged from the corresponding discharge unit 600.

[0035] Similarly, the ejection module 23-j includes 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 the same number of piezoelectric elements 60 as the plurality of ejection units 600.

[0036] Drive signals COMAj, COMBj, COMCj, a reference voltage signal VBSj, a clock signal SCKj, a print data signal SIj, and a latch signal LATj are input to the ejection module 23-j. The drive signals COMAj, COMBj, COMCj, the clock signal SCKj, the print data signal SIj, and the latch signal LATj are input to the drive signal selection circuit 200 included in the ejection module 23-j. Based on the input clock signal SCKj, print data signal SIj, and latch signal LATj, the drive signal selection circuit 200 generates a drive signal VOUT by selecting or not selecting each of the drive signals COMAj, COMBj, COMCj, and supplies it to one end of the piezoelectric element 60 included in the corresponding ejection unit 600. At this time, the reference voltage signal VBSj is supplied to the other end of the piezoelectric element 60. Then, 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 unit 600.

[0037] As described above, in the liquid ejection apparatus 1 according to the first embodiment, the control unit 2 controls the conveyance of the medium P by the conveyance unit 4 based on image data supplied from a host computer (not shown) or the like, and controls the ejection of ink from the liquid ejection module 20 included in the ejection unit 5. Thereby, the liquid ejection apparatus 1 can land a desired amount of ink at a desired position on the medium P and form a desired image on the medium P.

[0038] Here, the ejection modules 23-1 to 23-m of the liquid ejection module 20 have the same configuration, differing only in the input signals. Therefore, in the following description, when there is no need to distinguish between the ejection modules 23-1 to 23-m, they may simply be referred to as the ejection module 23. Also, in this case, the drive signals COMA1 to COMAm input to the ejection module 23 may be referred to as the drive signal COMA, the drive signals COMB1 to COMBm may be referred to as the drive signal COMB, the drive signals COMC1 to COMCm may be referred to as the drive signal COMC, the reference voltage signals VBS1 to VBSm may be referred to as the reference voltage signal VBS, the clock signals SCK1 to SCKm may be referred to as the clock signal SCK, the print data signals SI1 to SIm may be referred to as the print data signal SI, and the latch signals LAT1 to LATm may be referred to as the latch signal LAT.

[0039] 1.2 Functional Configuration of Drive Signal Selection Circuit Next, the configuration and operation of the drive signal selection circuit 200 of the ejection module 23 will be described. In explaining the configuration and operation of the drive signal selection circuit 200 of the ejection module 23, first, an example of the signal waveforms included in the drive signals COMA, COMB, and COMC input to the drive signal selection circuit 200 will be described.

[0040] FIG. 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 until the latch signal LAT rises next. The trapezoidal waveform Adp is a signal waveform that, when supplied to one end of the piezoelectric element 60, causes a predetermined amount of ink to be ejected from the ejection unit 600 corresponding to the piezoelectric element 60.

[0041] The drive signal COMB includes a trapezoidal waveform Bdp arranged in the 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 a smaller amount of ink than a predetermined amount to be ejected from the ejection unit 600 corresponding to the piezoelectric element 60.

[0042] That is, the driving amount of the piezoelectric element 60 when the driving signal COMA is supplied to the piezoelectric element 60 is larger than the driving amount of the piezoelectric element 60 when the driving signal COMB is supplied to the piezoelectric element 60. Also, the amount of ink ejected from the ejection unit 600 corresponding to the case where the driving signal COMA is supplied to the piezoelectric element 60 is larger than the amount of ink ejected from the ejection unit 600 corresponding to the case where the driving signal COMB is supplied to the piezoelectric element 60. In other words, when the driving signal COMA is supplied to the piezoelectric element 60, the amount of ink ejected from the ejection unit 600 corresponding to the piezoelectric element 60 is larger than the amount of ink ejected from the ejection unit 600 corresponding to the piezoelectric element 60 when the driving signal COMB is supplied to the piezoelectric element 60. Therefore, the amount of current generated along with the propagation of the driving signal COMA is larger than the amount of current generated along with the propagation of the driving signal COMB.

[0043] Also, the driving signal COMC includes a trapezoidal waveform Cdp arranged in the period T. This trapezoidal waveform Cdp is a signal waveform with a voltage amplitude smaller than those of the trapezoidal waveforms Adp and Bdp, and is a signal waveform that vibrates the ink near the nozzle orifice so that no ink is ejected from the ejection unit 600 corresponding to the piezoelectric element 60 when supplied to one end of the piezoelectric element 60. This trapezoidal waveform Cdp vibrates the ink near the nozzle orifice of the ejection unit 600 including the piezoelectric element 60 when supplied to the piezoelectric element 60. Thereby, the possibility of an increase in the viscosity of the ink near the nozzle orifice is reduced.

[0044] That is, the driving signals COMA and COMB drive the corresponding piezoelectric element 60 so that ink is ejected from the ejection unit 600, and the driving signal COMC drives the corresponding piezoelectric element 60 so that no ink is ejected from the ejection unit 600. Therefore, the driving amount of the piezoelectric element 60 when the driving signals COMA and COMB are supplied to the piezoelectric element 60 is larger than the driving amount of the piezoelectric element 60 when the driving signal COMC is supplied to the piezoelectric element 60. Therefore, the amount of current generated along with the propagation of the driving signals COMA and COMB is larger than the amount of current generated along with the propagation of the driving signal COMC.

[0045] Also, at the start timing and end timing of each of the trapezoidal waveforms Adp, Bdp, and Cdp, the voltage values of the trapezoidal waveforms Adp, Bdp, and Cdp are all common at the voltage Vc. In other words, the trapezoidal waveforms Adp, Bdp, and Cdp are signal waveforms that each start at the voltage Vc and end at the voltage Vc.

[0046] Here, in the following description, when the trapezoidal waveform Adp is supplied to one end of the piezoelectric element 60, the amount of ink ejected from the ejection portion 600 corresponding to the piezoelectric element 60 is referred to as a large amount, and when the trapezoidal waveform Bdp is supplied to one end of the piezoelectric element 60, the amount of ink ejected from the ejection portion 600 corresponding to the piezoelectric element 60 may be referred to as a small amount different from the large amount. Also, when the trapezoidal waveform Cdp is supplied to one end of the piezoelectric element 60, vibrating the ink near the nozzle orifice so that no ink is ejected from the ejection portion 600 corresponding to the piezoelectric element 60 may be referred to as fine 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 portion 600 included in the ejection module 23 ejects a predetermined amount of ink, which is a large amount, the drive circuit 52b outputs a drive signal COMB that drives the piezoelectric element 60 so that the ejection portion 600 included in the ejection module 23 ejects an amount of ink that is less than the predetermined amount and is a small amount, and the drive circuit 52c outputs a drive signal COMC that drives the piezoelectric element 60 so that the ejection portion 600 included in the ejection module 23 does not eject ink.

[0048] Note that the signal waveforms included in the drive signals COMA, COMB, and COMC are not limited to the signal waveforms illustrated in FIG. 3, and various signal waveforms may be used according to the type of ink ejected from the ejection unit 600, the number of piezoelectric elements 60 driven by the drive signals COMA, COMB, and COMC, the wiring length through which the drive signals COMA, COMB, and COMC propagate, and the like. That is, each of the drive signals COMA1 to COMAm may 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 be different 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, each of the drive signals COMB1 to COMBm may 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 be different 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, each of the drive signals COMC1 to COMCm may include a different signal waveform, and the amount of displacement generated in the piezoelectric element 60 when the drive signal COMC1 is supplied may be different from the amount of displacement generated in the piezoelectric element 60 when the drive signal COMCj is supplied.

[0049] Next, the configuration and operation of the drive signal selection circuit 200 that outputs the drive signal VOUT by selecting or not selecting each of the drive signals COMA, COMB, and COMC will be described. FIG. 4 is a diagram showing the functional configuration of the drive signal selection circuit 200. As shown in FIG. 4, the drive signal selection circuit 200 includes a selection control circuit 210 and a plurality of selection circuits 230.

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

[0051] The print data signal SI is a signal synchronized with the clock signal SCK, and includes 2-bit print data [SIH, SIL] for defining the dot size formed by the ink ejected from each of the n ejection units 600 as any one of "large dot LD", "small dot SD", "non-ejection ND", and "fine 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 connected in cascade with each other. The serially input print data signal SI is sequentially transferred to the subsequent stage of the shift register 212 connected in cascade according to the clock signal SCK. Then, by stopping the supply of the clock signal SCK, the n shift registers 212 hold 2-bit print data [SIH, SIL] corresponding to the ejection unit 600 corresponding to the shift register 212. In FIG. 4, in order to distinguish the n shift registers 212 connected in cascade, they are denoted as the 1st stage, 2nd stage, ..., nth stage from the upstream side to the downstream side where the print data signal SI is input.

[0053] Each of the n latch circuits 214 latches the 2-bit print data [SIH, SIL] held in the corresponding shift register 212 simultaneously 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, S3 with logic levels corresponding to the decoded content every period T. FIG. 5 is a diagram showing an example of the decoded content in the decoder 216. The decoder 216 outputs selection signals S1, S2, S3 with logic levels defined by the latched 2-bit print data [SIH, SIL] and the decoded content shown in FIG. 5. For example, when the 2-bit print data [SIH, SIL] latched by the corresponding latch circuit 214 is input as [1, 0] to the decoder 216 in the first embodiment, the decoder 216 sets the logic levels of the selection signals S1, S2, S3 to L, H, L levels at period T.

[0055] The selection circuit 230 is provided corresponding to each of the n ejection units 600. That is, the drive signal selection circuit 200 has n selection circuits 230. The selection signals S1, S2, S3 output by the decoder 216 corresponding to the same ejection unit 600 and the drive signals COMA, COMB, COMC are input to the selection circuit 230. The selection circuit 230 generates a drive signal VOUT by selecting or not selecting each of the drive signals COMA, COMB, COMC based on the selection signals S1, S2, S3 and the drive signals COMA, COMB, COMC, and outputs it to the corresponding ejection unit 600.

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

[0057] The selection signal S1 is input to the non-marked positive control terminal of the transfer gate 234a, while being logically inverted by the inverter 232a and input to the marked negative control terminal of the transfer gate 234a. Also, a drive signal COMA is supplied to the input terminal of the transfer gate 234a. The transfer gate 234a conducts between the input terminal and the output terminal when the input selection signal S1 is at the H level, and non-conducts between the input terminal and the output terminal when the input selection signal S1 is at the L level. That is, the transfer gate 234a outputs the drive signal COMA to the output terminal when the selection signal S1 is at the H level, and does not output the drive signal COMA to the output terminal when the selection signal S1 is at the L level.

[0058] The selection signal S2 is input to the non-marked positive control terminal of the transfer gate 234b, while being logically inverted by the inverter 232b and input to the marked negative control terminal of the transfer gate 234b. Also, a drive signal COMB is supplied to the input terminal of the transfer gate 234b. The transfer gate 234b conducts between the input terminal and the output terminal when the input selection signal S2 is at the H level, and non-conducts between the input terminal and the output terminal when the input selection signal S2 is at the L level. That is, the transfer gate 234b outputs the drive signal COMB to the output terminal when the selection signal S2 is at the H level, and does not output the drive signal COMB to the output terminal when the selection signal S2 is at the L level.

[0059] The selection signal S3 is input to the non - marked positive control terminal of the transfer gate 234c, while being logically inverted by the inverter 232c and input to the marked negative control terminal of the transfer gate 234c. Also, a drive signal COMC is supplied to the input terminal of the transfer gate 234c. When the input selection signal S3 is at the H level, the transfer gate 234c conducts between the input terminal and the output terminal, and when the input selection signal S3 is at the L level, the transfer gate 234c does not conduct between the input terminal and the output terminal. That is, when the selection signal S3 is at the H level, the transfer gate 234c outputs the drive signal COMC to the output terminal, and when the selection signal S3 is at the L 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 the drive signal VOUT to the corresponding ejection unit 600.

[0061] The operation of the drive signal selection circuit 200 will be described. FIG. 7 is a diagram for explaining the operation of the drive signal selection circuit 200. The print data signal SI is serially input in synchronization with the clock signal SCK and sequentially transferred by the shift register 212 corresponding to the ejection unit 600. Then, by stopping the input of the clock signal SCK, the 2 - bit print data [SIH, SIL] corresponding to each of the ejection units 600 is held in the corresponding shift register 212.

[0062] After that, 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] corresponding to the first-stage, second-stage, ..., n-stage shift registers 212 latched by the latch circuit 214 are illustrated as LT1, LT2, ..., LTn.

[0063] The decoder 216 outputs selection signals S1, S2, 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 logical levels of the selection signals S1, S2, S3 as H, L, L levels to the selection circuit 230 in the period T. As a result, the selection circuit 230 selects the trapezoidal waveform Adp in the period T and outputs a drive signal VOUT corresponding to "large dot LD". Also, when the print data [SIH, SIL] is [1, 0], the decoder 216 outputs the logical levels of the selection signals S1, S2, S3 as L, H, L levels to the selection circuit 230 in the period T. As a result, the selection circuit 230 selects the trapezoidal waveform Bdp in the period T and outputs a drive signal VOUT corresponding to "small dot SD". Also, when the print data [SIH, SIL] is [0, 1], the decoder 216 outputs the logical levels of the selection signals S1, S2, S3 as L, L, L levels to the selection circuit 230 in the period T. As a result, the selection circuit 230 does not select any of the trapezoidal waveforms Adp, Bdp, Cdp in the period T and outputs a drive signal VOUT corresponding to "non-ejection ND" at a constant voltage Vc. Also, when the print data [SIH, SIL] is [0, 0], the decoder 216 outputs the logical levels of the selection signals S1, S2, S3 as L, L, H levels to the selection circuit 230 in the period T. As a result, the selection circuit 230 selects the trapezoidal waveform Cdp in the period T and outputs a drive signal VOUT corresponding to "fine vibration BSD".

[0065] Here, when the selection circuit 230 does not select any of the trapezoidal waveforms Adp, Bdp, and Cdp, at one end of the corresponding piezoelectric element 60, the voltage Vc that was supplied to the piezoelectric element 60 immediately before is held by the capacitance component of the piezoelectric element 60. That is, when the selection circuit 230 outputs a constant drive signal VOUT at the voltage Vc, it includes the case where, when none of the trapezoidal waveforms Adp, Bdp, and Cdp are selected as the drive signal VOUT, the voltage Vc held immediately before by the capacitance component of the piezoelectric element 60 is supplied to the piezoelectric element 60 as the drive signal VOUT.

[0066] As described above, the drive signal selection circuit 200 generates a drive signal VOUT corresponding to each of the plurality of ejection units 600 by selecting or not selecting the drive signals COMA, COMB, and COMC based on the print data signal SI, the latch signal LAT, and the clock signal SCK, and outputs the drive signal to the corresponding ejection unit 600. Thereby, the amount of ink ejected from each of the plurality of ejection units 600 is individually controlled.

[0067] 1.3 Configuration of Drive Signal Output Circuit Next, the configuration and operation of the drive circuit 52 that outputs the drive signal COM will be described. FIG. 8 is a diagram showing the configuration of the drive circuit 52. The drive circuit 52 includes 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 a substrate (not shown) provided outside 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 a voltage signal DAC_HV and a voltage signal DAC_LV, and supplies them to the DAC 511. The DAC 511 converts a digital base drive signal do that defines the signal waveform of the input drive signal COM into an analog base drive signal ao that is a voltage value between the voltage signal DAC_HV and the voltage signal DAC_LV, and outputs it to the modulation circuit 510. Here, the maximum value of the voltage amplitude of the base drive signal ao is defined by the voltage signal DAC_HV, and the minimum value is defined by the voltage signal DAC_LV. That is, the voltage signal DAC_HV is the reference voltage on the high voltage side in the DAC 511, and the voltage signal DAC_LV is the reference voltage on the low voltage side in the DAC 511. And, the signal obtained by amplifying the analog base drive signal ao output from the DAC 511 becomes the drive signal COM. That is, the base drive signal ao corresponds to the target signal before amplification of the drive signal COM.

[0070] The modulation circuit 510 generates a modulation signal Ms obtained by modulating the base drive signal ao, and outputs it to the gate drive circuit 520. The modulation circuit 510 includes adders 512 and 513, a comparator 514, an inverter 515, an integrating attenuator 516, and an attenuator 517.

[0071] The integrating attenuator 516 attenuates and integrates the drive signal COM input via the terminal Vfb, and supplies it to the negative input terminal of the adder 512. Also, the base drive signal ao is input to the positive input terminal of the adder 512. Then, the adder 512 subtracts the voltage input to the negative input terminal from the voltage input to the positive input terminal, integrates the result, and supplies the integrated voltage to the positive input terminal of the adder 513.

[0072] The attenuator 517 attenuates the high-frequency component of the drive signal COM input via the terminal Ifb, and supplies the resulting voltage to the negative input terminal of the adder 513. Also, the voltage output from the adder 512 is input to the positive input terminal of the adder 513. Then, the adder 513 subtracts the voltage input to the negative input terminal from the voltage input to the positive input terminal, and outputs a voltage signal Os to the comparator 514.

[0073] Comparator 514 outputs a modulated signal Ms obtained by pulse-modulating the voltage signal Os output from adder 513. Specifically, comparator 514 becomes the H level when the voltage value of the voltage signal Os output from adder 513 is rising and becomes equal to or higher than a predetermined threshold value Vth1, and outputs a modulated signal Ms that becomes the L level when the voltage value of the voltage signal Os is falling and falls below a predetermined threshold value Vth2. These threshold values Vth1 and Vth2 are set in the relationship of threshold value Vth1 >= threshold value Vth2.

[0074] The modulated signal Ms output from comparator 514 is supplied to gate driver 521 included in gate drive circuit 520, and after the logic level is inverted by inverter 515, it is supplied to gate driver 522 included in gate drive circuit 520. That is, signals with mutually exclusive logic levels are input to gate driver 521 and gate driver 522. Here, the mutually exclusive logic level strictly means that the logic levels of the signals supplied to gate driver 521 and gate driver 522 do not become the H level at the same time. Specifically, it means that transistor M1 and transistor M2 included in amplifier circuit 550 described later do not turn on at the same time. Therefore, modulation circuit 510 may include a timing control circuit for controlling the timing between the modulated signal Ms supplied to gate driver 521 and the signal with the inverted logic level of the modulated signal Ms supplied to gate driver 522.

[0075] Gate drive circuit 520 includes gate driver 521 and gate driver 522. Gate driver 521 level-shifts the modulated signal Ms output from comparator 514 and outputs it as an amplification control signal Hgd from terminal Hdr.

[0076] Specifically, a voltage is supplied to the high-potential side of the power supply voltage of the gate driver 521 via the terminal Bst, and a voltage is supplied to the low-potential side via the terminal Sw. The terminal Bst is connected to one end of the capacitor C5 and the cathode of the anti-backflow diode D1. The terminal Sw is connected to the other end of the capacitor C5. Also, the anode of the diode D1 is connected to the terminal Gvd to which a voltage Vm, which is, for example, a DC voltage of 7.5V, is supplied from a power supply circuit (not shown). That is, a voltage Vm, which is a DC voltage, is supplied to the anode of the diode D1. Therefore, the potential difference between the terminal Bst and the terminal Sw is approximately equal to the voltage Vm. As a result, the gate driver 521 outputs, from the terminal Hdr, an amplified control signal Hgd having a voltage value larger than the voltage Vm with respect to the terminal Sw in accordance with the input modulation signal Ms.

[0077] The gate driver 522 operates on the lower potential side than the gate driver 521. The gate driver 522 level-shifts a signal obtained by inverting the logic level of the modulation signal Ms output from the comparator 514 by the inverter 515, and outputs it as an amplified control signal Lgd from the terminal Ldr.

[0078] Specifically, the voltage Vm is supplied to the high-potential side of the power supply voltage of the gate driver 522, and a ground potential of, for example, 0V is supplied to the low-potential side via the terminal Gnd. Then, the gate driver 522 outputs, from the terminal Ldr, an amplified control signal Lgd having a voltage value larger than the voltage Vm with respect to the terminal Gnd in accordance with a signal obtained by inverting the logic level of the input modulation signal Ms.

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

[0080] Transistor M1 is a surface-mounted FET (Field Effect Transistor). A voltage VHV, which is, for example, a DC voltage of 42V, is supplied as an amplified voltage to the drain of transistor M1. Also, the gate of transistor M1 is electrically connected to one end of resistor R1, and the other end of resistor R1 is electrically connected to terminal Hdr of integrated circuit 500. That is, an amplification control signal Hgd is supplied to the gate of transistor M1. And the source of transistor M1 is electrically connected to terminal Sw of integrated circuit 500.

[0081] Transistor M2 is a surface-mounted FET. The drain of transistor M2 is electrically connected to terminal Sw of integrated circuit 500. That is, the drain of transistor M2 and the source of transistor M1 are electrically connected to each other. The gate of transistor M2 is electrically connected to one end of resistor R2, and the other end of resistor R2 is electrically connected to terminal Ldr of integrated circuit 500. That is, an amplification control signal Lgd is supplied to the gate of transistor M2. And a ground potential is supplied to the source of 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 turned off and the transistor M2 is turned on, the potential of the node to which the terminal Sw is connected becomes the ground potential. Therefore, the voltage Vm is supplied to the terminal Bst. On the other hand, when the transistor M1 is turned on and the transistor M2 is turned off, the potential of the node to which the terminal Sw is connected becomes the voltage VHV. Therefore, a voltage signal with 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 according to the operations of the transistors M1 and M2, as the potential of the terminal Sw changes to 0V or the voltage VHV, the L level is the potential of the voltage VHV, and the H level is an amplified control signal Hgd with a potential of voltage VHV + voltage Vm is supplied to the gate of the transistor M1.

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

[0084] The amplifier circuit 550 configured as described above generates an amplified modulation signal AMs obtained 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. Then, the amplifier circuit 550 outputs the generated amplified modulation signal AMs to the demodulation circuit 560.

[0085] The demodulation circuit 560 generates a drive signal COM by demodulating the amplified modulation signal AMs output by the amplification circuit 550 and outputs it 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. Also, a ground potential is supplied to the other end of the capacitor C1. That is, in the demodulation circuit 560, the inductor L1 and the capacitor C1 constitute a low-pass filter. Then, the demodulation circuit 560 demodulates by smoothing the amplified modulation signal AMs output from the amplification circuit 550 with 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 a resistor R3 and a resistor 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 pulled up by the voltage VHV.

[0087] The feedback circuit 572 includes capacitors C2, C3, C4 and resistors R5, R6. One end of capacitor C2 is supplied with the drive signal COM, and the other end is connected to one end of resistor R5 and one end of resistor R6. The other end of resistor R5 is supplied with the ground potential. Thereby, capacitor C2 and resistor R5 function as a high pass filter. The cut-off frequency of this high pass filter is set to, for example, about 9 MHz. Also, the other end of resistor R6 is connected to one end of capacitor C4 and one end of capacitor C3. The other end of capacitor C3 is supplied with the ground potential. Thereby, resistor R6 and capacitor C3 function as a low pass filter. The cut-off frequency of this low pass filter is set to, for example, about 160 MHz. That is, 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] And the other end of capacitor C4 is connected to the terminal Ifb of the integrated circuit 500. Thereby, a signal with the DC component cut off among the high frequency components of the drive signal COM that has passed through the feedback circuit 572 functioning 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 base drive signal do by the demodulation circuit 560. Further, the drive signal COM is integrated and subtracted via the terminal Vfb and then fed back to the adder 512. As a result, the drive circuit 52 self-oscillates at a frequency determined by the feedback delay and the feedback transfer function. However, the feedback path via the terminal Vfb has a large delay amount. Therefore, only with the feedback via the terminal Vfb, it may not be possible to increase the self-oscillation frequency enough to sufficiently ensure the accuracy of the drive signal COM. Therefore, as shown in FIG. 8, a path for feeding back the high-frequency component of the drive signal COM is provided via the terminal Ifb separately from the path via the terminal Vfb, thereby reducing the delay in the entire circuit. As a result, the frequency of the voltage signal Os can be increased to a level sufficient to ensure the accuracy of the drive signal COM as compared with the case where the path via the terminal Ifb does not exist.

[0090] As described above, the drive circuit 52 generates the drive signal COM by digitally / analog-converting the input base drive signal do and then class-D amplifying the analog signal, and outputs the generated drive signal COM.

[0091] 1.4 Configuration of the Liquid Discharge Module Next, the structure of the liquid discharge module 20 will be described with reference to FIGS. 9 to 11. FIG. 9 is a diagram showing the structure of the liquid discharge module 20. Here, when explaining the structure of the liquid discharge module 20, FIGS. 9 to 11 illustrate arrows indicating the X1 direction, Y1 direction, and Z1 direction perpendicular to each other. Further, in the description of FIGS. 9 to 11, the starting side of the arrow indicating the X1 direction is referred to as the -X1 side, the tip side is referred to as the +X1 side, the starting side of the arrow indicating the Y1 direction is referred to as the -Y1 side, the tip side is referred to as the +Y1 side, and the starting side of the arrow indicating the Z1 direction is referred to as the -Z1 side, and the tip side may be referred to as the +Z1 side. Further, in the following description, the liquid discharge module 20 included in the liquid discharge device 1 in the first embodiment will be described as having six discharge modules 23. And when distinguishing each of the six discharge modules 23, each of the six discharge modules 23 may be referred to as discharge modules 23-1 to 23-6.

[0092] As shown in FIG. 9, the liquid ejection module 20 includes a housing 31, a common substrate 33, a flow path structure 34, a head substrate 35, a distribution flow path 37, a fixing 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 flow path 37, and the fixing plate 39 are arranged along the Z1 direction from the -Z1 side to the +Z1 side, and are laminated in the order of the fixing plate 39, the distribution flow path 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 flow path 37, and the fixing plate 39 so as to support them. The common substrate 33 stands upright while being held by the housing 31 on the +Z1 side of the housing 31, and six ejection modules 23 are positioned between the distribution flow path 37 and the fixing plate 39 such that a part thereof is exposed outside the liquid ejection module 20.

[0093] In explaining the structure of the liquid ejection module 20, first, the structure of the ejection module 23 included in the liquid ejection module 20 will be described. FIG. 10 is a diagram showing an example of the structure of the ejection module 23, and FIG. 11 is a diagram showing an example of a cross section of the ejection module 23. Here, FIG. 11 is a cross-sectional view when the ejection module 23 is cut along the A-a line shown in FIG. 10, and the A-a line shown in FIG. 10 is a virtual line segment passing through the introduction path 661 included in the ejection module 23 and passing through the nozzles N1 and N2.

[0094] As shown in FIGS. 10 and 11, the discharge module 23 has a plurality of nozzles N1 arranged in parallel and a plurality of nozzles N2 arranged in parallel. The total number of the nozzles N1 and N2 included in the discharge module 23 is n, which is the same as the number of discharge portions 600 included in the discharge module 23. In the first embodiment, the description will be made on the assumption that the number of the nozzles N1 and the number of the nozzles N2 included in the discharge module 23 are the same. That is, the description will be made on the assumption that the discharge module 23 has n / 2 nozzles N1 and n / 2 nozzles N2. Here, in the following description, when it is not necessary to distinguish between the nozzle N1 and the nozzle N2, they may simply be referred to as the nozzle N.

[0095] The discharge module 23 has a wiring member 388, a case 660, a protection 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 partitioned by a plurality of partition walls by anisotropic etching from one surface side are arranged in parallel corresponding to the nozzles N1, and pressure chambers CB2 partitioned by a plurality of partition walls by anisotropic etching from one surface side are arranged in parallel corresponding to the nozzles N2. Here, in the following description, when it is not necessary to distinguish between the pressure chamber CB1 and the pressure chamber CB2, they may simply be referred to as the pressure chamber 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 on the -Z1 side of the nozzle plate 623 where the nozzle N opens may be referred to as the liquid injection surface 623a.

[0098] On the -Z1 side of the flow path forming substrate 642 and on the +Z1 side of the nozzle plate 623, a communication plate 630 is positioned. The communication plate 630 is provided with a nozzle communication path RR1 that communicates the pressure chamber CB1 and the nozzle N1, and a nozzle communication path RR2 that communicates the pressure chamber CB2 and the nozzle N2. Further, the communication plate 630 is independently provided with a pressure chamber communication path RK1 that communicates the end of the pressure chamber CB1 and the manifold MN1, and a pressure chamber communication path RK2 that communicates the end of the pressure chamber CB2 and the manifold MN2, corresponding to each of the pressure chambers CB1 and CB2.

[0099] The manifold MN1 includes a supply communication path RA1 and a connection communication path RX1. The supply communication path RA1 is provided to penetrate the communication plate 630 along the Z1 direction, and the connection communication path RX1 is provided to open on the nozzle plate 623 side of the communication plate 630 without penetrating the communication plate 630 in the Z1 direction and extending to the middle in the Z1 direction. Similarly, the manifold MN2 includes a supply communication path RA2 and a connection communication path RX2. The supply communication path RA2 is provided to penetrate the communication plate 630 along the Z1 direction, and the connection communication path RX2 is provided to open on the nozzle plate 623 side of the communication plate 630 without penetrating the communication plate 630 in the Z1 direction and extending to the middle in the Z1 direction. Then, the connection communication path RX1 included in the manifold MN1 communicates with the corresponding pressure chamber CB1 through the pressure chamber communication path RK1, and the connection communication path RX2 included in the manifold MN2 communicates with the corresponding pressure chamber CB2 through the pressure chamber communication path RK2.

[0100] Here, in the following description, when there is no need to distinguish between the nozzle communication path RR1 and the nozzle communication path RR2, it may simply be referred to as the nozzle communication path RR; when there is no need to distinguish between the manifold MN1 and the manifold MN2, it may simply be referred to as the manifold MN; when there is no need to distinguish between the supply communication path RA1 and the supply communication path RA2, it may simply be referred to as the supply communication path RA; and when there is no need to distinguish between the connection communication path RX1 and the connection communication path RX2, it may simply be referred to as the connection communication path RX.

[0101] On the +Z1 side surface of the flow path forming substrate 642, the diaphragm 610 is positioned. Also, on the +Z1 side surface of the diaphragm 610, piezoelectric elements 60 are formed in two rows corresponding to the nozzles N1, 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 common to the pressure chambers CB. Then, 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 common electrode which is the other electrode of the piezoelectric element 60.

[0102] On the +Z1 side surface of the flow path forming substrate 642, a protective substrate 641 is joined. The protective substrate 641 forms a protective space 644 for protecting the piezoelectric element 60. Also, the protective substrate 641 is provided with a through hole 643 penetrating along the Z1 direction. The end of the lead electrode 611 drawn from the electrode of the piezoelectric element 60 is extended so as to be exposed inside this through hole 643. Then, a wiring member 388 is electrically connected to the end of the lead electrode 611 exposed inside the through hole 643.

[0103] Also, a case 660 that defines a part of a manifold MN communicating with a plurality of pressure chambers CB is fixed to the protective substrate 641 and the communication plate 630. The case 660 is joined to the protective substrate 641 and is also joined to the communication plate 630. Specifically, the case 660 has a recess 665 on its -Z1 side surface in which the flow path forming substrate 642 and the protective substrate 641 are accommodated. The recess 665 has an opening area wider than the surface where the protective substrate 641 is joined to the flow path forming substrate 642. And with the flow path forming substrate 642 etc. accommodated in the recess 665, the -Z1 side opening surface of the recess 665 is sealed by the communication plate 630. Thereby, a supply communication path RB1 and a supply communication path RB2 are defined at the outer peripheral portion 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 path RB1 and the supply communication path RB2, it may be simply referred to as the supply communication path RB.

[0104] Further, a compliance substrate 620 is provided on the surface of the communication plate 630 where the supply communication path RA and the connection communication path RX open. The compliance substrate 620 seals the openings of the supply communication path RA and the connection communication path RX. 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 metal such as stainless steel.

[0105] The case 660 is provided with an introduction path 661 for supplying ink to the manifold MN. Further, the case 660 is provided with a connection port 662 which is an opening communicating with the through hole 643 of the protection substrate 641 and penetrating 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 ejection module 23 and the head substrate 35. For example, an FPC can be used. Further, an integrated circuit 201 is mounted on the wiring member 388 by COF (Chip On Film). At least a part of the above-described drive signal selection circuit 200 is mounted on this integrated circuit 201.

[0107] In the ejection module 23 configured as described above, the drive signal VOUT output from the drive signal selection circuit 200 and the reference voltage signal VBS are supplied to the piezoelectric element 60 via the wiring member 388. Then, the piezoelectric element 60 is driven by a change in the potential difference between the drive signal VOUT and the reference voltage signal VBS. Along with the driving of the piezoelectric element 60, the diaphragm 610 is displaced in the vertical direction, and the internal pressure of the pressure chamber CB changes. Then, due to the change in the internal pressure of the pressure chamber CB, the ink stored inside the pressure chamber CB is ejected from the corresponding nozzle N. Here, in the ejection module 23, the configuration including the nozzle N, the nozzle communication path RR, the pressure chamber CB, the piezoelectric element 60, and the diaphragm 610 corresponds to the above-described ejection unit 600. That is, 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 ejection module 23. The fixing plate 39 fixes six ejection modules 23. Specifically, the fixing plate 39 has six openings 391 penetrating along the Z2 direction. The liquid ejection surfaces 623a of the ejection modules 23 are exposed from each of these six openings 391. That is, six ejection modules 23 are fixed to the fixing plate 39 such that the liquid ejection surfaces 623a are exposed from the respective openings 391 corresponding thereto.

[0109] The distribution flow path 37 is located on the +Z1 side of the ejection module 23. Four introduction parts 373 are provided on the +Z1 side surface of the distribution flow path 37. The four introduction parts 373 are flow path pipes protruding in the +Z1 direction along the Z1 direction from the +Z1 side surface of the distribution flow path 37 and communicate with a flow path hole (not shown) formed on the -Z1 side surface of the flow path structure 34. Also, on the -Z1 side surface of the distribution flow path 37, flow path pipes (not shown) communicating with the four introduction parts 373 are located. The flow path pipes (not shown) located on the -Z1 side surface of the distribution flow path 37 communicate with the introduction paths 661 each of the six ejection modules 23 has. Further, the distribution flow path 37 has six openings 371 penetrating along the Z1 direction. Wiring members 388 each of the six ejection modules 23 has are inserted through these six openings 371.

[0110] The head substrate 35 is located on the +Z1 side of the distribution channel 37. A wiring member FC that is electrically connected to the collective substrate 33 described later is attached to the head substrate 35. Further, four openings 351 and notches 352 and 353 are formed in the head substrate 35. Wiring members 388 included in the ejection modules 23-2 to 23-5 are inserted through the four openings 351. Then, the respective wiring members 388 of the ejection 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. Further, the wiring member 388 included in the ejection module 23-1 passes through the notch 352, and the wiring member 388 included in the ejection module 23-6 passes through the notch 353. Then, the respective wiring members 388 of the ejection modules 23-1 and 23-6 that have passed through the notches 352 and 353 are electrically connected to the head substrate 35 by solder or the like.

[0111] Further, four notches 355 are formed at the four corners of the head substrate 35. Four introduction parts 373 pass through the four notches 355. Then, the four introduction parts 373 that have passed through the notches 355 are connected to a channel structure 34 located on the +Z1 side of the head substrate 35.

[0112] The flow path structure 34 has a flow path plate Su1 and a flow path plate Su2. The flow path plate Su1 and the flow path plate Su2 are laminated along the Z1 direction with the flow path plate Su1 positioned on the +Z1 side and the flow path plate Su2 positioned on the -Z1 side, and are joined to each other by an adhesive or the like. Further, the flow path structure 34 has four introduction portions 341 that project toward the +Z1 side along the Z1 direction on the surface on the +Z1 side. The four introduction portions 341 communicate with a flow path hole (not shown) formed on the surface on the -Z1 side of the flow path structure 34 via an ink flow path formed inside the flow path structure 34. And a flow path hole (not shown) formed on the surface on the -Z1 side of the flow path structure 34 communicates with the four introduction portions 373. Furthermore, a through hole 343 that penetrates along the Z1 direction is formed in the flow path structure 34. A wiring member FC that is electrically connected to the head substrate 35 is inserted into the through hole 343. And inside the flow path structure 34, in addition to the ink flow path that communicates the introduction portion 341 and the flow path hole (not shown) formed on the surface on the -Z1 side, a filter or the like for catching foreign matter contained in the ink flowing through the ink flow path may be provided.

[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 path 37, and the fixing plate 39, and supports the flow path structure 34, the head substrate 35, the distribution flow path 37, and the fixing plate 39. The housing 31 has four openings 311, a collective substrate insertion portion 313, and a holding member 315.

[0114] Each of the four openings 311 has inserted therein the four introduction portions 341 that the flow path structure 34 has. And ink is supplied to the four introduction portions 341 that have passed through the four openings 311 via a tube or the like (not shown) from the liquid container 3.

[0115] The holding member 315 sandwiches the assembly substrate 33 in a state where a part of the assembly substrate 33 is inserted through the assembly substrate insertion portion 313. The assembly substrate 33 is provided with a connection portion 330. Various signals such as a data signal DATA, drive signals COMA, COMB, COMC, a reference voltage signal VBS, and other power supply voltages output from the head drive module 10 are input to the connection portion 330 via the wiring member 30. Further, a wiring member FC included in the head substrate 35 is electrically connected to the assembly substrate 33. Thereby, the assembly substrate 33 and the head substrate 35 are electrically connected. A semiconductor device including the above-described restoration circuit 220 may be provided on the assembly substrate 33. In FIG. 9, the case where the assembly substrate 33 has one connection portion 330 is illustrated. However, when the liquid ejection device 1 has a plurality of wiring members 30 and various signals such as a data signal DATA, drive signals COMA, COMB, COMC, a reference voltage signal VBS, and other power supply voltages output from the head drive module 10 are input to the assembly substrate 33 via the plurality of wiring members 30, the assembly substrate 33 may have a plurality of connection portions 330 corresponding to each of the plurality of wiring members 30.

[0116] In the liquid ejection module 20 configured as described above, the ink stored in the liquid container 3 is supplied by communicating the liquid container 3 and the introduction portion 341 via a tube or the like (not shown). Then, the ink supplied to the liquid ejection module 20 is guided to a flow path hole (not shown) formed on the -Z1 side surface of the flow path structure 34 via an ink flow path formed inside the flow path structure 34, and then supplied to four introduction portions 373 included in the distribution flow path 37. The ink supplied to the distribution flow path 37 via the four introduction portions 373 is distributed corresponding to each of the six ejection modules 23 in an ink flow path (not shown) formed inside the distribution flow path 37, and then supplied to an introduction path 661 included in the corresponding ejection module 23. Then, the ink supplied to the ejection module 23 via the introduction path 661 is stored in a pressure chamber CB included in the ejection portion 600.

[0117] Further, the head drive module 10 and the liquid ejection module 20 are electrically connected by one or more wiring members 30. As a result, various signals including drive signals COMA, COMB, COMC, a reference voltage signal VBS, and a data signal DATA output from the head drive module 10 are supplied to the liquid ejection module 20. The various signals including the drive signals COMA, COMB, 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 each of the ejection modules 23-1 to 23-6 from the data signal DATA. Then, drive signals VOUT corresponding to each of the n and the ejection units 600 are generated by the integrated circuit 201 including the drive signal selection circuit 200 provided in the wiring member 388 and supplied to the piezoelectric elements 60 included in the corresponding ejection units 600. As a result, the piezoelectric elements 60 are driven and the ink stored in the pressure chamber CB is ejected.

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

[0119] 1.5 Structure of the head drive module Next, the structure of the head drive module 10 will be described with reference to FIG. 12. Here, FIG. 12 shows arrows indicating the X2 direction, Y2 direction, and Z2 direction that are independent of the aforementioned X1 direction, Y1 direction, and Z1 direction and are perpendicular to each other. Also, in the following description, the starting side of the arrow indicating the X2 direction may be referred to as the -X2 side and the tip side may be referred to as the +X2 side, the starting side of the arrow indicating the Y2 direction may be referred to as the -Y2 side and the tip side may be referred to as the +Y2 side, and the starting side of the arrow indicating the Z2 direction may be referred to as the -Z2 side and the tip side may be referred to as the +Z2 side.

[0120] FIG. 12 is a diagram showing an example of the structure of the head driving module 10. As shown in FIG. 12, the head driving module 10 includes a drive circuit board 800, a heat conduction member group 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 plurality of drive circuits 52 described above 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 by 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 when the heat sink 710 is attached to the wiring board 810, it contacts both the plurality of drive circuits 52 provided on the wiring board 810 and the heat sink 710. Thereby, the heat conduction member group 720 conducts the heat generated in the plurality of drive circuits 52 provided on the wiring board 810 to the heat sink 710.

[0122] The details of the structure of the head driving module 10 configured as described above will be described with reference to the drawings.

[0123] First, a specific example of the structure of the drive circuit board 800 included in the head driving 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 a plurality of 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 a plurality of insulating layers 840. And the first layer 831, the second layer 832, the third layer 833, the fourth layer 834, and the fifth layer 835 are located in the order of the first layer 831, the second layer 832, the third layer 833, the fourth layer 834, the fifth layer 835 from the +Z2 side to the -Z2 side along the Z2 direction, and the plurality of insulating layers 840 are located 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 along the Z2 direction.

[0124] In the first layer 831 and the fifth layer 835, a plurality of electronic components that constitute various circuits including a plurality of drive circuits 52 are provided. Further, in the first layer 831, the second layer 832, the third layer 833, the fourth layer 834, and the fifth layer 835, a plurality of wiring patterns are formed that electrically connect the electronic components provided in the first layer 831 and the fifth layer 835 and propagate various signals. The plurality of wiring patterns formed in 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 excellent in electrical conductivity, and are formed, for example, by subjecting a copper foil to an etching process. Further, the insulating layer 840 functions as an insulator layer that insulates between the plurality of wiring patterns formed in the first layer 831, the second layer 832, the third layer 833, the fourth layer 834, and the fifth layer 835. As such an insulating layer 840, for example, an epoxy glass formed by impregnating a cloth of glass fiber with an epoxy resin can be used.

[0125] That is, the wiring board 810 in the first embodiment is a multilayer board including the first layer 831, the second layer 832, the third layer 833, the fourth layer 834, and the fifth layer 835. The first layer 831 and the fifth layer 835 constitute the surface layer of the wiring board 810, and the second layer 832, the third layer 833, and the fourth layer 834 constitute the inner layer of the wiring board 810. Note that the wiring board 810 may have a through hole (not shown) that penetrates the insulating layer 840 along the Z2 direction and electrically connects the first layer 831, the second layer 832, the third layer 833, the fourth layer 834, and the fifth layer 835 to each other. Further, in the following description, it is described that the electronic components that constitute various circuits including the plurality of drive circuits 52 included in the drive circuit board 800 are provided in the first layer 831. However, a part of the electronic components that constitute various circuits including the plurality of drive circuits 52 included in the drive circuit board 800 may be provided in the fifth layer 835.

[0126] Details of the 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 FIGS. 14 to 17. FIG. 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] As shown in FIG. 14, the 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 the wiring board 810, side 812 is located on the -X2 side of the wiring board 810, side 813 intersects both sides 811 and 812 and is located on the +Y2 side of the wiring board 810, and side 814 intersects both sides 811 and 812 and is located on the -Y2 side of the wiring board 810.

[0128] On the 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 side 811 and is electrically connected to the control unit 2. Specifically, a cable (not shown) electrically connected to the control unit 2 is attached to the connection part CN1. Thereby, a signal including the image information signal IP output by the control unit 2 is supplied to the head drive 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 drive module 10 without a cable.

[0130] The connection part CN2 is located along the side 812 of the wiring board 810 and is electrically connected to the liquid ejection module 20. Specifically, one end of the wiring member 30 is attached to the connection part CN2. Also, the other end of the wiring member 30 is connected to the connection part 330 that the liquid ejection module 20 has. Thereby, signals including the drive signals COMA1 to COMA6, COMB1 to COMB6, COMC1 to COMC6, and the data signal DATA output by the head drive module 10 are supplied from the connection part 330 to the liquid ejection module 20 via the connection part CN2 and the wiring member 30. That is, the connection part CN2 is provided on the wiring board 810 and electrically connects the wiring board 810 and the liquid ejection module 20, thereby propagating the drive signals COMA1 to COMA6, COMB1 to COMB6, COMC1 to COMC6 to the liquid ejection module 20. Here, the connection parts CN2 and 330 may be B-to-B connectors that can be electrically connected to each other without passing through a cable or the like. In this case, the connection parts CN2 and 330 constitute 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, the image information signal IP is input to the integrated circuit 101 via the connection part CN1. Then, the integrated circuit 101 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. In the liquid ejection device 1 of the first embodiment, although it is described that the integrated circuit 101 includes all of the control circuit 100 and all of the conversion circuit 120, part of the control circuit 100 or part of the conversion circuit 120 may be configured outside the integrated circuit 101.

[0132] Here, in FIG. 14, an example is illustrated in which the integrated circuit 101 is disposed on the first layer 831 of the wiring board 810 together with a plurality of drive circuits 52. However, the integrated circuit 101 may be disposed on a substrate (not shown) different from the wiring board 810. As shown in FIG. 14, when the integrated circuit 101 and the plurality of drive circuits 52 are mounted on a common substrate, the wiring pattern through which signals are propagated between the plurality of drive circuits 52 and the integrated circuit 101 can be shortened. Thereby, the possibility that noise or the like is superimposed on the signals propagated between the plurality of drive circuits 52 and the integrated circuit 101 is reduced. On the other hand, the plurality of drive circuits 52 generate a larger amount of heat compared to the integrated circuit 101. Therefore, if the heat generated in the plurality of drive circuits 52 contributes to the integrated circuit 101, the stability of the operation of the integrated circuit 101 may decrease. To address such a problem, by mounting the integrated circuit 101 on a substrate different from the plurality of drive circuits 52, the possibility that the heat generated in the plurality of drive circuits 52 contributes to the integrated circuit 101 can be reduced.

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

[0134] In this case, the transistors M1 and M2 included in each of the plurality of drive circuits 52 are arranged side by side such that the transistor M1 is on the +X2 side and the transistor M2 is on the -X2 side along the X2 direction. The inductor L1 is located on the -Y2 side of the transistors M1 and M2 arranged side by side along the X2 direction, and the integrated circuit 500 is located on the +Y2 side of the transistors M1 and M2 arranged 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 arranged in this order along the direction from the side 813 to the side 814 in the first layer 831 of the wiring board 810.

[0135] Further, the integrated circuits 500 included in each of the plurality of drive circuits 52 are arranged side by side along the X2 direction, the transistors M1 and M2 arranged side by side are arranged alternately along the X2 direction, and the inductor L1 is arranged side by side along the X2 direction. That is, in the first layer 831 of the wiring board 810, there are formed a column of integrated circuits 500 arranged side by side from the side 812 to the side 811, a column of transistors M1 and M2 arranged side by side from the side 812 to the side 811, and a column of inductors L1 arranged side by side from the side 812 to the side 811.

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

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

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

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

[0140] Specifically, a drive circuit 52a1 that outputs a drive signal COMA1 for driving the piezoelectric element 60 included in the ejection module 23-1 so that ink is ejected from the ejection unit 600 included in the ejection module 23-1, and a drive circuit 52b1 that outputs a drive signal COMB1 for driving the piezoelectric element 60 included in the ejection module 23-1 so that ink is ejected from the ejection unit 600 included in the ejection module 23-1 are positioned adjacent to each other along the X2 direction in 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] A drive circuit 52a2 that outputs a drive signal COMA2 for driving a piezoelectric element 60 included in a discharge module 23-2 so that ink is discharged from a discharge unit 600 included in the discharge module 23-2, and a drive circuit 52b2 that outputs a drive signal COMB2 for driving the piezoelectric element 60 included in the discharge module 23-2 so that ink is discharged from the discharge unit 600 included in the discharge module 23-2 are adjacent to each other on the first layer 831 of a wiring board 810 along the X2 direction, with the drive circuit 52a2 on the -X2 side and the drive circuit 52b2 on the +X2 side on the +X2 side of the drive circuit 52b1.

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

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

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

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

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

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

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

[0149] Among the signals supplied from the head drive module 10 to the liquid ejection module 20 as described above, the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 output by each of the plurality of drive circuits 52 are, as described above, supplied to the corresponding piezoelectric elements 60 and are analog signals for driving the piezoelectric elements 60. When waveform distortion occurs in such drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6, it directly contributes to the ink ejection state from the corresponding ejection unit 600. That is, from the viewpoint of improving the ejection accuracy of the ink ejected from the liquid ejection module 20, reducing the possibility 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 the ink ejected from the liquid ejection module 20.

[0150] Therefore, in the head drive module 10, an example of the configuration of the wiring pattern through which the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 output by each of the drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 propagate will be described with reference to FIGS. 15 to 17.

[0151] FIG. 15 is a diagram showing an example of a wiring pattern provided in the second layer 832 of the wiring board 810. FIG. 16 is a diagram showing an example of a wiring pattern provided in the third layer 833 of the wiring board 810. FIG. 17 is a diagram showing an example of a wiring pattern provided in the fourth layer 834 of the wiring board 810. Here, in the head drive module 10 of the first embodiment, a plurality of wiring patterns through which drive signals COMA1 to COMA6 propagate are provided in the second layer 832 of the wiring board 810, and a plurality of wiring patterns through which drive signals COMB1 to COMB6 propagate are provided in the third layer 833 of the wiring board 810. A plurality of wiring patterns through which drive signals COMC1 to COMC6 propagate will be described as being provided in the fourth layer 834 of the wiring board 810. Note that FIGS. 15 to 17 are perspective views when the wiring board 810 is viewed from the +Z2 side to the -Z2 side along the Z2 direction. In FIGS. 15 to 17, a plurality of drive circuits 52, connection parts CN1 and CN2, and the integrated circuit 101 provided in the first layer 831 of the wiring board 810 are shown by broken 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 part CN2 in the first layer 831. Then, as shown in FIG. 15, one end of the inductor L1 through which the drive circuit 52a1 outputs the drive signal COMA1 is electrically connected to one end of a wiring WA1 provided in the second layer 832 via a through hole (not shown). The wiring WA1 extends along the X2 direction in the second layer 832. The other end of the wiring WA1 is electrically connected to the connection part CN2 provided in 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 part CN2 and propagates the drive signal COMA1. Thereby, the drive signal COMA1 output by the drive circuit 52a1 is propagated to the connection part CN2.

[0153] Also, 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 in the first layer 831. Then, as shown in FIG. 16, one end of the inductor L1 through which the drive circuit 52b1 outputs the drive signal COMB1 is electrically connected to one end of a wiring WB1 provided in the third layer 833 via a through hole (not shown). The wiring WB1 extends along the X2 direction in the third layer 833. And the other end of the wiring WB1 is electrically connected to a connection part CN2 provided in the first layer 831 via a through hole (not shown). That is, the wiring board 810 electrically connects the drive circuit 52b1 and the connection part CN2 and includes the wiring WB1 that propagates the drive signal COMB1. Thereby, the drive signal COMB1 output by the drive circuit 52b1 is propagated to the connection part CN2.

[0154] Also, 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 in the first layer 831. Then, as shown in FIG. 15, one end of the inductor L1 through which the drive circuit 52a2 outputs the drive signal COMA2 is electrically connected to one end of a wiring WA2 provided in the second layer 832 via a through hole (not shown). The wiring WA2 extends along the X2 direction in the second layer 832. And the other end of the wiring WA2 is electrically connected to a connection part CN2 provided in the first layer 831 via a through hole (not shown). That is, the wiring board 810 electrically connects the drive circuit 52a2 and the connection part CN2 and includes the wiring WA2 that propagates the drive signal COMA2. Thereby, the drive signal COMA2 output by the drive circuit 52a2 is propagated to the connection part CN2.

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

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

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

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

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

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

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

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

[0163] And the other end of the wiring WA6 is electrically connected to the connection portion CN2 provided in 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. Thereby, the drive signal COMA6 output by the drive circuit 52a6 is propagated to the connection portion CN2.

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

[0165] Also, 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 in the first layer 831. Then, as shown in FIG. 17, one end of the inductor L1 through which the drive circuit 52c1 outputs the drive signal COMC1 is electrically connected to one end of the wiring WC1 provided in the fourth layer 834 via a through hole (not shown). The wiring WC1 extends along the X2 direction in the fourth layer 834. And the other end of the wiring WC1 is electrically connected to the connection portion CN2 provided in the first layer 831 via a through hole (not shown). That is, the wiring board 810 includes the wiring WC1 that electrically connects the drive circuit 52c1 and the connection portion CN2 and propagates the drive signal COMC1. Thereby, the drive signal COMC1 output by the drive circuit 52c1 is propagated to the connection portion CN2.

[0166] Also, 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 in the first layer 831. Then, as shown in FIG. 17, one end of the inductor L1 through which the drive circuit 52c2 outputs the drive signal COMC2 is electrically connected to one end of a wiring WC2 provided in the fourth layer 834 via a through hole (not shown). The wiring WC2 extends along the X2 direction in the fourth layer 834. And the other end of the wiring WC2 is electrically connected to a connection portion CN2 provided in the first layer 831 via a through hole (not shown). That is, the wiring board 810 electrically connects the drive circuit 52c2 and the connection portion CN2 and includes the wiring WC2 that propagates the drive signal COMC2. Thereby, the drive signal COMC2 output by the drive circuit 52c2 is propagated to the connection portion CN2.

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

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

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

[0170] Also, 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 in the first layer 831. And, as shown in FIG. 17, one end of the inductor L1 through which the drive circuit 52c6 outputs the drive signal COMC6 is electrically connected to one end of the wiring WC6 provided in the fourth layer 834 via a through hole (not shown). The wiring WC6 extends along the X2 direction in the fourth layer 834. And the other end of the wiring WC6 is electrically connected to the connection part CN2 provided in the first layer 831 via a through hole (not shown). That is, the wiring board 810 includes the wiring WC6 that electrically connects the drive circuit 52c6 and the connection part CN2 and propagates the drive signal COMC6. Thereby, the drive signal COMC6 output by the drive circuit 52c6 is propagated to the connection part 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, 52c1 to 52c6 as a plurality of drive circuits 52. The wiring board 810 provided on the drive circuit board 800 includes wirings WA1 to WA6, WB1 to WB6, WC1 to WC6 as a plurality of wiring patterns that electrically connect each of the plurality of drive circuits 52 and the connection part CN2. And the drive circuits 52a1 to 52a6, 52b1 to 52b6, 52c1 to 52c6 are arranged in order of drive circuits 52a1, 52b1, 52a2, 52b2, 52a3, 52b3, 52a4, 52b4, 52a5, 52b5, 52a6, 52b6, 52c1, 52c2, 52c3, 52c4, 52c5, 52c6 from the +X2 side to the -X2 side along the X2 direction on the wiring board 810.

[0172] That is, the drive circuits 52a1, 52b1, and 52c1 that output the drive signals COMA1, COMB1, and COMC1 to the piezoelectric element 60 included in the ejection module 23-1 are located in the order of the drive circuit 52a1, the drive circuit 52b1, and the drive circuit 52c1 along the X2 direction from the side 812 where the connection portion CN2 is located to the side 811 where the connection portion CN1 is located in the first layer 831 of the wiring board 810. Therefore, the length of the wiring WA1 that electrically connects the drive circuit 52a1 and the connection portion CN2 is shorter than the lengths of the wiring WB1 that electrically connects the drive circuit 52b1 and the connection portion CN2 and the wiring WC1 that electrically connects the drive circuit 52c1 and the connection portion CN2, and the length of the wiring WB1 that electrically connects the drive circuit 52b1 and the connection portion CN2 is shorter than the length of the wiring WC1 that electrically connects 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] Also, the drive circuits 52a2, 52b2, and 52c2 that output the drive signals COMA2, COMB2, and COMC2 to the piezoelectric element 60 included in the ejection module 23-2 are located in the order of the drive circuit 52a2, the drive circuit 52b2, and the drive circuit 52c2 along the X2 direction from the side 812 where the connection portion CN2 is located to the side 811 where the connection portion CN1 is located in the first layer 831 of the wiring board 810. Therefore, the length of the wiring WA2 that electrically connects the drive circuit 52a2 and the connection portion CN2 is shorter than the lengths of the wiring WB2 that electrically connects the drive circuit 52b2 and the connection portion CN2 and the wiring WC2 that electrically connects the drive circuit 52c2 and the connection portion CN2, and the length of the wiring WB2 that electrically connects the drive circuit 52b2 and the connection portion CN2 is shorter than the length of the wiring WC2 that electrically connects the drive circuit 52c2 and the connection portion CN2. That is, the wiring WB2 is longer than the wiring WA2 and shorter than the wiring WC2.

[0174] Also, drive circuits 52a3, 52b3, and 52c3 that output drive signals COMA3, COMB3, and COMC3 to piezoelectric element 60 included in ejection module 23-3 are located in the order of drive circuit 52a3, drive circuit 52b3, and drive circuit 52c3 along the X2 direction from side 812 where connection portion CN2 is located toward side 811 where connection portion CN1 is located in the first layer 831 of wiring board 810. Therefore, the length of wiring WA3 that electrically connects drive circuit 52a3 and connection portion CN2 is shorter than the lengths of wiring WB3 that electrically connects drive circuit 52b3 and connection portion CN2 and wiring WC3 that electrically connects drive circuit 52c3 and connection portion CN2, and the length of wiring WB3 that electrically connects drive circuit 52b3 and connection portion CN2 is shorter than the length of wiring WC3 that electrically connects drive circuit 52c3 and connection portion CN2. That is, wiring WB3 is longer than wiring WA3 and shorter than wiring WC3.

[0175] Also, drive circuits 52a4, 52b4, and 52c4 that output drive signals COMA4, COMB4, and COMC4 to piezoelectric element 60 included in ejection module 23-4 are located in the order of drive circuit 52a4, drive circuit 52b4, and drive circuit 52c4 along the X2 direction from side 812 where connection portion CN2 is located toward side 811 where connection portion CN1 is located in the first layer 831 of wiring board 810. Therefore, the length of wiring WA4 that electrically connects drive circuit 52a4 and connection portion CN2 is shorter than the lengths of wiring WB4 that electrically connects drive circuit 52b4 and connection portion CN2 and wiring WC4 that electrically connects drive circuit 52c4 and connection portion CN2, and the length of wiring WB4 that electrically connects drive circuit 52b4 and connection portion CN2 is shorter than the length of wiring WC4 that electrically connects drive circuit 52c4 and connection portion CN2. That is, wiring WB4 is longer than wiring WA4 and shorter than wiring WC4.

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

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

[0178] Then, as shown in FIG. 14, in the liquid ejection device 1 of the first embodiment, on the first layer 831 of the wiring board 810, drive signals COMA1 and COMB1 for driving the piezoelectric element 60 corresponding to ink ejection from the ejection unit 600 of the ejection module 23-1 are output from the side 812 where the connection portion CN2 is located toward the side 811 where the connection portion CN1 is located. Drive circuits 52a1 and 52b1, drive signals COMA2 and COMB2 for driving the piezoelectric element 60 corresponding to ink ejection from the ejection unit 600 of the ejection module 23-2 are output. Drive circuits 52a2 and 52b2, drive signals COMA3 and COMB3 for driving the piezoelectric element 60 corresponding to ink ejection from the ejection unit 600 of the ejection module 23-3 are output. Drive circuits 52a3 and 52b3, drive signals COMA4 and COMB4 for driving the piezoelectric element 60 corresponding to ink ejection from the ejection unit 600 of the ejection module 23-4 are output. Drive circuits 52a4 and 52b4, drive signals COMA5 and COMB5 for driving the piezoelectric element 60 corresponding to ink ejection from the ejection unit 600 of the ejection module 23-5 are output. Drive circuits 52a5 and 52b5, drive signals COMA6 and COMB6 for driving the piezoelectric element 60 corresponding to ink ejection from the ejection unit 600 of the ejection module 23-6 are output. Drive circuits 52a6 and 52b6 are located in this order, and drive circuits 52c1 to 52c6 for outputting drive signals COMC1 to COMC6 for driving the piezoelectric element 60 corresponding to non-ink ejection are on the +X2 side of the drive circuits 52a1 to 52a6 and 52b1 to 52b6 on the first layer 831 of the wiring board 810, from the side 812 where the connection portion CN2 is located toward the side 811 where the connection portion CN1 is located, and are located in the order of drive circuits 52c1, 52c2, 52c3, 52c4, 52c5, 52c6.

[0179] That is, a drive circuit 52a1 that outputs a drive signal COMA1 for driving a piezoelectric element 60 corresponding to ink being ejected from an ejection unit 600 included in an ejection module 23-1 is located closest to a connection part CN2 among a plurality of drive circuits 52 arranged side by side on a wiring board 810 along the X2 direction, and a drive circuit 52c6 that outputs a drive signal COMC6 for driving a piezoelectric element 60 corresponding to ink not being ejected from an ejection unit 600 included in an ejection module 23-6 is located farthest from the connection part CN2 among the plurality of drive circuits 52 arranged side by side on the wiring board 810 along the X2 direction.

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

[0181] In the head drive module 10 configured as described above, as described above, the voltage amplitudes of the drive signals COMA1 and COMB1 are larger than the voltage amplitude of the drive signal COMC1 that drives the piezoelectric element 60 so that ink is not ejected from the nozzles N of the ejection module 23-1 because the piezoelectric element 60 is driven so that ink is ejected from the nozzles N of the ejection module 23-1. That is, the amount of current generated with the propagation of the drive signals COMA1 and COMB1 is larger than the amount of current generated with 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 compared to the drive signal COMC1. By making the wiring lengths of the wirings WA1 and WB1 through which the drive signals COMA1 and COMB1 that are susceptible to the influence of impedance generated in such a wiring pattern propagate shorter than the wiring length of the wiring WC1 through which the drive signal COMC1 propagates, the waveform accuracy of the drive signals COMA1 and COMB1 that directly contribute to ink ejection can be improved. As a result, the ink ejection accuracy in the liquid ejection device 1 is improved.

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

[0183] Similarly, the amount of current generated due to the propagation of drive signals COMA2 and COMB2 supplied to the piezoelectric element 60 of ejection module 23-2 is larger than the amount of current generated due to the propagation of drive signal COMC2, and the amount of current generated due to the propagation of drive signal COMA2 is larger than the amount of current generated due to the propagation of drive signal COMB2. Therefore, by making the wiring lengths of wirings WA2 and WB2 through which drive signals COMA2 and COMB2 propagate shorter than the wiring length of wiring WC2 through which drive signal COMC2 propagates, the waveform accuracy of drive signals COMA2 and COMB2 output from head drive module 10 can be improved. Furthermore, by making the wiring length of wiring WA2 through which drive signal COMA2 propagates shorter than the wiring length of wiring WB2 through which drive signal COMB2 propagates, the possibility of a decrease in the waveform accuracy of drive signal COMA2 is reduced, and the ejection accuracy of ink in liquid ejection device 1 is improved.

[0184] Similarly, the amount of current generated due to the propagation of drive signals COMA3 and COMB3 supplied to the piezoelectric element 60 of ejection module 23-3 is larger than the amount of current generated due to the propagation of drive signal COMC3, and the amount of current generated due to the propagation of drive signal COMA3 is larger than the amount of current generated due to the propagation of drive signal COMB3. Therefore, by making the wiring lengths of wirings WA3 and WB3 through which drive signals COMA3 and COMB3 propagate shorter than the wiring length of wiring WC3 through which drive signal COMC3 propagates, the waveform accuracy of drive signals COMA3 and COMB3 output from head drive module 10 can be improved. Furthermore, by making the wiring length of wiring WA3 through which drive signal COMA3 propagates shorter than the wiring length of wiring WB3 through which drive signal COMB3 propagates, the possibility of a decrease in the waveform accuracy of drive signal COMA3 is reduced, and the ejection accuracy of ink in liquid ejection device 1 is improved.

[0185] Similarly, the amount of current generated due to the propagation of drive signals COMA4 and COMB4 supplied to the piezoelectric element 60 included in the ejection module 23-4 is larger than the amount of current generated due to the propagation of drive signal COMC4, and the amount of current generated due to the propagation of drive signal COMA4 is larger than the amount of current generated due to the propagation of drive signal COMB4. Therefore, by making the wiring lengths of wirings WA4 and WB4 through which drive signals COMA4 and COMB4 propagate shorter than the wiring length of wiring WC4 through which drive signal COMC4 propagates, the waveform accuracy of drive signals COMA4 and COMB4 output from the head drive module 10 can be improved. Furthermore, by making the wiring length of wiring WA4 through which drive signal COMA4 propagates shorter than the wiring length of wiring WB4 through which drive signal COMB4 propagates, the risk of a decrease in the waveform accuracy of drive signal COMA4 is reduced, and the ejection accuracy of ink in the liquid ejection apparatus 1 is improved.

[0186] Similarly, the amount of current generated due to the propagation of drive signals COMA5 and COMB5 supplied to the piezoelectric element 60 included in the ejection module 23-5 is larger than the amount of current generated due to the propagation of drive signal COMC5, and the amount of current generated due to the propagation of drive signal COMA5 is larger than the amount of current generated due to the propagation of drive signal COMB5. Therefore, by making the wiring lengths of wirings WA5 and WB5 through which drive signals COMA5 and COMB5 propagate shorter than the wiring length of wiring WC5 through which drive signal COMC5 propagates, the waveform accuracy of drive signals COMA5 and COMB5 output from the head drive module 10 can be improved. Furthermore, by making the wiring length of wiring WA5 through which drive signal COMA5 propagates shorter than the wiring length of wiring WB5 through which drive signal COMB5 propagates, the risk of a decrease in the waveform accuracy of drive signal COMA5 is reduced, and the ejection accuracy of ink in the liquid ejection apparatus 1 is improved.

[0187] Similarly, the amount of current generated due to the propagation of the drive signals COMA6 and COMB6 supplied to the piezoelectric element 60 of the ejection module 23-6 is larger than the amount of current generated due to the propagation of the drive signal COMC6, and the amount of current generated due to the propagation of the drive signal COMA6 is larger than the amount of current generated due to the propagation of the drive signal COMB6. Therefore, by making the wiring lengths of the wirings WA6 and WB6 through which the drive signals COMA6 and COMB6 propagate shorter than the wiring length of the wiring WC6 through which the drive signal COMC6 propagates, the waveform accuracy of the drive signals COMA6 and COMB6 output from the head drive module 10 can be improved. Furthermore, by making the wiring length of the wiring WA6 through which the drive signal COMA6 propagates shorter than the wiring length of the wiring WB6 through which the drive signal COMB6 propagates, the possibility of a decrease in the waveform accuracy of the drive signal COMA6 is reduced, and the ink ejection accuracy in 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 and 52b1 to 52b6 that output the drive signals COMA1 to COMA6 and COMB1 to COMB6 for driving 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 portion CN2 than the drive circuits 52c1 to 52c6 that output the drive signals COMC1 to COMC6 for driving 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 FIGS. 15 to 17, each of the drive circuits 52a1, 52b1, 52a2, 52b2, 52a3, 52b3, 52a4, 52b4, 52a5, 52b5, 52a6, and 52b6 is electrically connected to the connection portion CN2, and the wiring lengths of the wirings WA1 to WA6 and WB1 to WB6 through which the drive signals COMA1 to COMA6 and COMB1 to COMB6 propagate can be made shorter than the wiring lengths of the wirings WC1 to WC6 through which the drive signals COMC1 to COMC6 propagate by electrically connecting each of the drive circuits 52c1, 52c2, 52c3, 52c4, 52c5, and 52c6 to the connection portion CN2.

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

[0190] Here, in the drive circuit board 800 of the first embodiment, drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 are provided on the first layer 831 of the wiring board 810, wirings WA1 to WA6 that propagate drive signals COMA1 to COMA6 are provided on the second layer 832 of the wiring board 810, wirings WB1 to WB6 that propagate drive signals COMB1 to COMB6 are provided on the third layer 833, and wirings WC1 to WC6 that propagate drive signals COMC1 to COMC6 are provided on the fourth layer 834. However, the present invention is not limited to this. For example, a part 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, and the fifth layer 835. Also, at least a part of the wirings WA1 to WA6 that propagate drive signals COMA1 to COMA6, the wirings WB1 to WB6 that propagate drive signals COMB1 to COMB6, and the wirings WC1 to WC6 that propagate drive signals COMC1 to COMC6 may be provided in the same wiring layer. Further, in the drive circuit board 800 of the first embodiment, a case where the second layer 832, the third layer 833, and the fourth layer 834 are laminated in the order of the second layer 832, the third layer 833, and the fourth layer 834 from the +Z2 side to the -Z2 side along the Z2 direction is illustrated. However, the lamination order in the wiring board 810 is not limited to this. Further, in the first embodiment, the wiring board 810 is described as having the second layer 832, the third layer 833, and the fourth layer 834 as inner layers. However, the wiring board 810 may include a plurality of inner layers such as a layer through which reference voltage signals VBS1 to VBS6 propagate, a layer through which various control signals including a data signal DATA propagate, and a layer held at a ground potential.

[0191] Further, as shown in FIG. 14, the 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 in parallel along the side 813 of the wiring board 810, and some different ones of the plurality of through holes 820 are arranged in parallel along the side 814 of the wiring board 810. That is, the wiring board 810 has a plurality of through holes 820 arranged in two rows in parallel along the X2 direction. Here, being arranged in parallel along the side 813 of the wiring board 810 means that the shortest distance between each of the plurality of through holes 820 arranged in parallel and the side 813 of the wiring board 810 is shorter than the shortest distance from the side 814 of the wiring board 810, and the plurality of through holes 820 are arranged in parallel along the X2 direction. Being arranged in parallel along the side 814 of the wiring board 810 means that the shortest distance between each of the plurality of through holes 820 arranged in parallel and the side 814 of the wiring board 810 is shorter than the shortest distance from the side 813 of the wiring board 810, and the plurality of through holes 820 are arranged in parallel along the X2 direction.

[0192] And at least one of the plurality of through holes 820 arranged in parallel along the side 813 of the wiring board 810 and at least one of the plurality of through holes 820 arranged in parallel along the side 814 of the wiring board 810 are located between the connection portion CN2 and the drive circuit 52a1. That is, at least one of the plurality of through holes 820 is located between the connection portion CN2 and the 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 parallel along the side 813 of the wiring board 810 and at least one different one of the plurality of through holes 820 arranged in parallel along the side 814 of the wiring board 810 are located between the drive circuit 52a1 and the drive circuit 52b1. That is, at least one of the plurality of through holes 820 is located between the drive circuit 52a1 and the drive circuit 52b1 in the direction along the X2 direction.

[0194] At least one different one of the plurality of vias 820 arranged side by side along the side 813 of the wiring board 810, and at least one different one of the plurality of vias 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52b1 and the drive circuit 52a2. That is, at least one of the plurality of vias 820 is located between the drive circuit 52b1 and the drive circuit 52a2 in the direction along the X2 direction.

[0195] At least one different one of the plurality of vias 820 arranged side by side along the side 813 of the wiring board 810, and at least one different one of the plurality of vias 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52a2 and the drive circuit 52b2. That is, at least one of the plurality of vias 820 is located between the drive circuit 52a2 and the drive circuit 52b2 in the direction along the X2 direction.

[0196] At least one different one of the plurality of vias 820 arranged side by side along the side 813 of the wiring board 810, and at least one different one of the plurality of vias 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52b2 and the drive circuit 52a3. That is, at least one of the plurality of vias 820 is located between the drive circuit 52b2 and the drive circuit 52a3 in the direction along the X2 direction.

[0197] At least one different one of the plurality of vias 820 arranged side by side along the side 813 of the wiring board 810, and at least one different one of the plurality of vias 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52a3 and the drive circuit 52b3. That is, at least one of the plurality of vias 820 is located between the drive circuit 52a3 and the drive circuit 52b3 in the direction along the X2 direction.

[0198] At least one different one of the plurality of through-holes 820 arranged side by side along the side 813 of the wiring board 810 and at least one different one of the plurality of through-holes 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52b3 and the drive circuit 52a4. That is, at least one of the plurality of through-holes 820 is located between the drive circuit 52b3 and the drive circuit 52a4 in the direction along the X2 direction.

[0199] At least one different one of the plurality of through-holes 820 arranged side by side along the side 813 of the wiring board 810 and at least one different one of the plurality of through-holes 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52a4 and the drive circuit 52b4. That is, at least one of the plurality of through-holes 820 is located between the drive circuit 52a4 and the drive circuit 52b4 in the direction along the X2 direction.

[0200] At least one different one of the plurality of through-holes 820 arranged side by side along the side 813 of the wiring board 810 and at least one different one of the plurality of through-holes 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52b4 and the drive circuit 52a5. That is, at least one of the plurality of through-holes 820 is located between the drive circuit 52b4 and the drive circuit 52a5 in the direction along the X2 direction.

[0201] At least one different one of the plurality of through-holes 820 arranged side by side along the side 813 of the wiring board 810 and at least one different one of the plurality of through-holes 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52a5 and the drive circuit 52b5. That is, at least one of the plurality of through-holes 820 is located between the drive circuit 52a5 and the drive circuit 52b5 in the direction along the X2 direction.

[0202] At least one different one of the plurality of through-holes 820 arranged side by side along the side 813 of the wiring board 810 and at least one different one of the plurality of through-holes 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52b5 and the drive circuit 52a6. That is, at least one of the plurality of through-holes 820 is located between the drive circuit 52b5 and the drive circuit 52a6 in the direction along the X2 direction.

[0203] At least one different one of the plurality of through-holes 820 arranged side by side along the side 813 of the wiring board 810 and at least one different one of the plurality of through-holes 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52a6 and the drive circuit 52b6. That is, at least one of the plurality of through-holes 820 is located between the drive circuit 52a6 and the drive circuit 52b6 in the direction along the X2 direction.

[0204] At least one different one of the plurality of through-holes 820 arranged side by side along the side 813 of the wiring board 810 and at least one different one of the plurality of through-holes 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52b6 and the drive circuit 52c1. That is, at least one of the plurality of through-holes 820 is located between the drive circuit 52b6 and the 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 the side 813 of the wiring board 810, and at least one different one of the plurality of through-holes 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52c3 and the drive circuit 52c4. At least one different one of the plurality of through-holes 820 arranged side by side along the side 813 of the wiring board 810, and at least one different one of the plurality of through-holes 820 arranged side by side along the side 814 of the wiring board 810 are located between the drive circuit 52c6 and the integrated circuit 101. At least one different one of the plurality of through-holes 820 arranged side by side along the side 813 of the wiring board 810, and at least one different one of the plurality of through-holes 820 arranged side by side along the side 814 of the wiring board 810 are located between the integrated circuit 101 and the connection portion CN1.

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

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

[0208] Returning to FIG. 12, next, a specific example of the structure of the heat sink 710 included in the head drive module 10 will be described. The heat sink 710 is positioned on the +Z2 side of the drive circuit board 800. The heat sink 710 includes a bottom 711, side portions 712 and 713, protruding portions 715, 716, and 717, and a plurality of fin portions 718.

[0209] The bottom 711 is located facing the wiring board 810 and is substantially rectangular extending in the plane formed by the X2 direction and the Y2 direction. The side part 712 protrudes from the -Y2 side end of the bottom 711 toward the -Z2 side and extends along the X2 direction. At least a part of the -Z2 side end of this side part 712 is in contact with the -Y2 side end of the wiring board 810. The side part 713 protrudes from the +Y2 side end of the bottom 711 toward the -Z2 side and extends along the X2 direction. At least a part of the -Z2 side end of this side part 713 is in contact with the +Y2 side end of the wiring board 810. That is, the heat sink 710 forms an accommodation space that opens on the -Z2 side with the bottom 711 and the side parts 712, 713. And a 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 provided so as to cover the plurality of drive circuits 52.

[0210] The protrusions 715, 716, 717 are provided corresponding to the inductor L1, transistors M1, M2, and integrated circuit 500 provided on the wiring board 810 inside the accommodation space formed by the bottom 711 and the side parts 712, 713. 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 protrusions 716 are located corresponding to the transistors M1, M2 provided on the wiring board 810, protrude from the bottom 711 toward the -Z2 side, and extend 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 plurality of fin portions 718 each project from the bottom 711 toward the -Z2 side, extend along the X2 direction, and are spaced apart from each other in the Y2 direction. Since the heat sink 710 has the plurality of fin portions 718, the surface area of the heat sink 710 increases, and as a result, the heat dissipation performance of the heat sink 710 is improved. The number of fin portions 718 of such a heat sink 710 is set based on an optimal interval defined according to the amount of heat that the heat sink 710 dissipates from the heat generated in the drive circuit board 800, the length of the fin portions 718 along the Z2 direction, the air flow applied to 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, thereby dissipating the heat generated by the plurality of drive circuits 52 provided on the wiring board 810. That is, the head drive module 10 is attached to the wiring board 810 and includes a heat sink 710 that dissipates the heat of at least any one of the plurality of drive circuits 52. Such a heat sink 710 is a material having sufficient rigidity to protect the drive circuit 52 in addition to high thermal conductivity, and is configured to include, for example, 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 configured to include a metal such as aluminum, iron, or copper and is provided so as to cover the plurality of drive circuits 52. Thereby, the heat sink 710 functions not only as a shielding material that dissipates the heat generated by the plurality of drive circuits 52 but also reduces the possibility that external disturbance noise contributes to the plurality of drive circuits 52. As a result, the waveform accuracy of the drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 output by the plurality of drive circuits 52 is further improved.

[0214] The heat conduction member group 720 is located between the drive circuit board 800 and the heat sink 710 in the direction along the Z2 direction. By contacting both the heat-generating electronic components of the drive circuit board 800 and the heat sink 710, the heat conduction member group 720 enhances the heat conduction efficiency of the heat conducted from the drive circuit board 800 to the heat sink 710. As such a heat conduction member group 720, it is preferably a substance having elasticity, flame retardancy, and electrical insulation properties in addition to heat conductivity. For example, it can include silicone or acrylic resin, and a gel sheet or a rubber sheet having high heat conductivity can be used. Thereby, the heat conduction member group 720 functions as a heat conduction member that conducts the heat generated in the drive circuit board 800 to the heat sink 710, functions as an insulation member for ensuring electrical insulation performance between the drive circuit board 800 and the heat sink 710, and further functions as a buffer member that relieves the stress generated when the heat sink 710 is attached to the drive circuit board 800.

[0215] The heat conduction member group 720 includes heat conduction members 730, 740, 750, and 760. The heat conduction member 730 is positioned between the inductor L1 that each of the plurality of drive circuits 52 has and the protrusion 715 that the heat sink 710 has, and in a state where the heat sink 710 is attached to the drive circuit board 800, it contacts both the inductor L1 that each of the plurality of drive circuits 52 has and the protrusion 715. Thereby, the heat conduction member 730 enhances the conduction efficiency of the heat generated in the inductor L1 to the heat sink 710. The heat conduction member 740 is positioned between the transistor M1 that each of the plurality of drive circuits 52 has and the protrusion 716 that the heat sink 710 has, and in a state where the heat sink 710 is attached to the drive circuit board 800, it contacts both the transistor M1 that each of the plurality of drive circuits 52 has and the protrusion 716. Thereby, the heat conduction member 740 enhances the conduction efficiency of the heat generated in the transistor M1 to the heat sink 710. The heat conduction member 750 is positioned between the transistor M2 that each of the plurality of drive circuits 52 has and the protrusion 716 that the heat sink 710 has, and in a state where the heat sink 710 is attached to the drive circuit board 800, it contacts both the transistor M2 that each of the plurality of drive circuits 52 has and the protrusion 716. Thereby, the heat conduction member 750 enhances the conduction efficiency of the heat generated in the transistor M2 to the heat sink 710. The heat conduction member 760 is positioned between the integrated circuit 500 that each of the plurality of drive circuits 52 has and the protrusion 717 that the heat sink 710 has, and in a state where the heat sink 710 is attached to the drive circuit board 800, it contacts both the integrated circuit 500 that each of the plurality of drive circuits 52 has and the protrusion 717. Thereby, the heat conduction member 760 enhances the conduction efficiency of the heat generated in the transistor M2 to the heat sink 710.

[0216] Each of the plurality of screws 780 is made of a metal such as steel, iron, aluminum, or stainless steel, and is inserted from the -Z2 side to the +Z2 side through each of the plurality of through holes 820 provided in the wiring board 810 of the drive circuit board 800, and is fastened 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 plurality of screws 780 are inserted through the through holes 820 located between the connection portion CN2 and the drive circuit 52a1 among the plurality of through holes 820 formed in the wiring board 810. Then, by fastening the screws 780 to the side portions 712, 713 of the heat sink 710, the heat sink 710 is attached to the wiring board 810.

[0218] Similarly, some of the plurality of screws 780 are inserted through through-holes 820 that are arranged side by side along side 813 of the wiring board 810 and are located between drive circuit 52a1 and drive circuit 52b1, between drive circuit 52b1 and drive circuit 52a2, between drive circuit 52a2 and drive circuit 52b2, between drive circuit 52b2 and drive circuit 52a3, between drive circuit 52a3 and drive circuit 52b3, between drive circuit 52b3 and drive circuit 52a4, between drive circuit 52a4 and drive circuit 52b4, between drive circuit 52b4 and drive circuit 52a5, between drive circuit 52a5 and drive circuit 52b5, between drive circuit 52b5 and drive circuit 52a6, between drive circuit 52a6 and drive circuit 52b6, between drive circuit 52b6 and drive circuit 52c1, between drive circuit 52c3 and drive circuit 52c4, between drive circuit 52c6 and integrated circuit 101, and between integrated circuit 101 and connection portion CN1. Then, by tightening the screws 780 to side portions 712, 713 of the heat sink 710, the heat sink 710 is attached to the wiring board 810.

[0219] As described above, a plurality of screws 780 are inserted through a plurality of through holes 820 provided in the wiring board 810 and tightened to the side portions 712, 713, whereby the heat sink 710 including the side portions 712, 713 is attached to the wiring board 810 of the drive circuit board 800. 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. That is, the thermal contact efficiency between the inductor L1, transistors M1, M2, integrated circuit 500 with a large heat generation amount and the heat sink 710 is improved. As a result, the heat of the inductor L1, transistors M1, M2, integrated circuit 500 with a large heat generation amount can be conducted to the heat sink 710 more efficiently, and the temperature rise of the drive circuit 52 of the drive circuit board 800 is reduced.

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

[0221] Such drive circuits 52a1, 52b1, and 52c1 are arranged in the order of drive circuits 52a1, 52b1, and 52c1 in a direction along the X2 direction on the first layer 831 of the wiring board 810, and a through hole 820 through which a screw 780 is inserted is located between the drive circuit 52a1 with a large heat generation amount and the drive circuit 52b1. That is, the heat sink 710 is attached to the wiring board 810 by a metal screw 780 between the drive circuit 52a1 that outputs a drive signal COMA1 for driving the piezoelectric element 60 to eject ink and the drive circuit 52b1 that outputs a drive signal COMB1 for driving the piezoelectric element 60 to eject ink. Thereby, among the heat generated by the drive circuit 52a1 and the drive circuit 52b1, the heat conducted to the wiring board 810 is released to the heat sink 710 via the metal screw 780. That is, the heat generated by the drive circuit 52a1 and the drive circuit 52b1 is conducted to the heat sink 710 via the heat conducting members 730, 740, 750, and 760 and is also conducted to the heat sink 710 via the metal screw 780. Thereby, the heat dissipation efficiency of the drive circuits 52a1 and 52b1 with a large heat generation amount is improved.

[0222] Similarly, the heat generation amounts of the drive circuits 52a2 and 52b2 are larger than the heat generation amount of the drive circuit 52c2, and the heat generation amount of the drive circuit 52a2 is larger than the heat generation amount of the drive circuit 52b2. Such drive circuits 52a2, 52b2, and 52c2 are arranged in the order of drive circuits 52a2, 52b2, and 52c2 in a direction along the X2 direction on the first layer 831 of the wiring board 810, and a through hole 820 through which a screw 780 is inserted is located between the drive circuit 52a2 and the drive circuit 52b2. Thereby, among the heat generated by the drive circuit 52a2 and the drive circuit 52b2, the heat conducted to the wiring board 810 is released to the heat sink 710 via the metal screw 780. That is, the heat generated by the drive circuit 52a2 and the drive circuit 52b2 is conducted to the heat sink 710 via the heat conducting members 730, 740, 750, and 760 and is also conducted to the heat sink 710 via the metal screw 780. Thereby, the heat dissipation efficiency of the drive circuits 52a2 and 52b2 with a large heat generation amount is improved.

[0223] Similarly, the heat generation amounts of the drive circuits 52a3 and 52b3 are larger than that of the drive circuit 52c3, and the heat generation amount of the drive circuit 52a3 is larger than that of the drive circuit 52b3. Such drive circuits 52a3, 52b3, and 52c3 are arranged side by side in the direction along the X2 direction in the first layer 831 of the wiring board 810 in the order of the drive circuits 52a3, 52b3, and 52c3, and a through hole 820 through which a screw 780 is inserted is located between the drive circuit 52a3 and the drive circuit 52b3. Thereby, among the heat generated by the drive circuits 52a3 and 52b3, the heat conducted to the wiring board 810 is released to the heat sink 710 via the metal screw 780. That is, the heat generated by the drive circuits 52a3 and 52b3 is conducted to the heat sink 710 via the heat conduction members 730, 740, 750, and 760 and is also conducted to the heat sink 710 via the metal screw 780. Thereby, the heat dissipation efficiency of the drive circuits 52a3 and 52b3 with large heat generation amounts is improved.

[0224] Similarly, the heat generation amounts of the drive circuits 52a4 and 52b4 are larger than that of the drive circuit 52c4, and the heat generation amount of the drive circuit 52a4 is larger than that of the drive circuit 52b4. Such drive circuits 52a4, 52b4, and 52c4 are arranged side by side in the direction along the X2 direction in the first layer 831 of the wiring board 810 in the order of the drive circuits 52a4, 52b4, and 52c4, and a through hole 820 through which a screw 780 is inserted is located between the drive circuit 52a4 and the drive circuit 52b4. Thereby, among the heat generated by the drive circuits 52a4 and 52b4, the heat conducted to the wiring board 810 is released to the heat sink 710 via the metal screw 780. That is, the heat generated by the drive circuits 52a4 and 52b4 is conducted to the heat sink 710 via the heat conduction members 730, 740, 750, and 760 and is also conducted to the heat sink 710 via the metal screw 780. Thereby, the heat dissipation efficiency of the drive circuits 52a4 and 52b4 with large heat generation amounts is improved.

[0225] Similarly, the heat generation amounts of the drive circuits 52a5 and 52b5 are larger than that of the drive circuit 52c5, and the heat generation amount of the drive circuit 52a5 is larger than that of the drive circuit 52b5. Such drive circuits 52a5, 52b5, and 52c5 are arranged side by side in the direction along the X2 direction in the first layer 831 of the wiring board 810 in the order of the drive circuits 52a5, 52b5, and 52c5, and a through hole 820 through which a screw 780 is inserted is located between the drive circuit 52a5 and the drive circuit 52b5. Thereby, among the heat generated by the drive circuits 52a5 and 52b5, the heat conducted to the wiring board 810 is released to the heat sink 710 via the metal screw 780. That is, the heat generated by the drive circuits 52a5 and 52b5 is conducted to the heat sink 710 via the heat conductive members 730, 740, 750, and 760 and is also conducted to the heat sink 710 via the metal screw 780. Thereby, the heat dissipation efficiency of the drive circuits 52a5 and 52b5 with large heat generation amounts is improved.

[0226] Similarly, the heat generation amounts of the drive circuits 52a6 and 52b6 are larger than that of the drive circuit 52c6, and the heat generation amount of the drive circuit 52a6 is larger than that of the drive circuit 52b6. Such drive circuits 52a6, 52b6, and 52c6 are arranged side by side in the direction along the X2 direction in the first layer 831 of the wiring board 810 in the order of the drive circuits 52a6, 52b6, and 52c6, and a through hole 820 through which a screw 780 is inserted is located between the drive circuit 52a6 and the drive circuit 52b6. Thereby, among the heat generated by the drive circuits 52a6 and 52b6, the heat conducted to the wiring board 810 is released to the heat sink 710 via the metal screw 780. That is, the heat generated by the drive circuits 52a6 and 52b6 is conducted to the heat sink 710 via the heat conductive members 730, 740, 750, and 760 and is also conducted to the heat sink 710 via the metal screw 780. Thereby, the heat dissipation efficiency of the drive circuits 52a6 and 52b6 with large heat generation amounts is improved.

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

[0228] In such a head drive module 10, the wiring board 810 has through holes 820 respectively between the drive circuit 52b1 and the drive circuit 52a2, between the drive circuit 52b2 and the drive circuit 52a3, between the drive circuit 52b3 and the drive circuit 52a4, between the drive circuit 52b4 and the drive circuit 52a5, and between the drive circuit 52b5 and the drive circuit 52a6, and the heat sink 710 is attached to the wiring board 810 by screws 780 inserted through the through holes 820 respectively positioned between the drive circuit 52b1 and the drive circuit 52a2, between the drive circuit 52b2 and the drive circuit 52a3, between the drive circuit 52b3 and the drive circuit 52a4, between the drive circuit 52b4 and the drive circuit 52a5, and between the drive circuit 52b5 and the drive circuit 52a6. Thus, even when the drive circuits 52a1 to 52a6 and 52b1 to 52b6 that generate a large amount of heat are concentratedly arranged on the wiring board 810, the heat dissipation efficiency of the heat generated by the drive circuits 52a1 to 52a6 and 52b1 to 52b6 can be further enhanced.

[0229] Here, instead of a plurality of metal screws 780, the head drive module 10 may attach the heat sink 710 to the drive circuit board 800 using, for example, metal rivets. Also, a part of the heat sink 710 passes through the through hole 820, and a part of the heat sink 710 passing through the through hole 820 is attached to the metal part of the drive circuit board 800 by solder or the like, so that the heat sink 710 may be attached to the drive circuit board 800. However, in the case of a configuration in which a plurality of drive circuits 52 included in the drive circuit board 800 as shown in the first embodiment are housed inside the heat sink 710, when the heat sink 710 is attached to the drive circuit board 800 using metal rivets, solder, or the like, the maintainability of the drive circuit board 800 is reduced. That is, from the viewpoint of improving the maintainability of the drive circuit board 800, it is preferable to use a metal screw 780 that enables easy attachment and detachment between the drive circuit board 800 and the heat sink 710 and has excellent thermal conductivity.

[0230] The cooling fan 770 is located on the -Z2 side of the heat sink 710. And the cooling fan 770 introduces outside air into the inside of the head drive module 10 through an opening 714 provided in the upper part on the +X2 side of the heat sink 710.

[0231] Specifically, the cooling fan 770 is attached so as to cover the opening 714. The opening 714 is a through hole that penetrates the heat sink 710 along the Z2 direction, and communicates with the inside of the head drive module 10 when the heat sink 710 is attached to the drive circuit board 800. Then, when the cooling fan 770 operates, outside air is introduced into the inside of the head drive module 10 through the opening 714. Thereby, the circulation efficiency of the air floating inside the head drive module 10 is improved, and the heat release efficiency of the heat generated by the drive circuit board 800 by the heat sink 710 is improved.

[0232] Here, the cooling fan 770 only needs to be attached so as to improve the circulation efficiency of the air floating inside the head drive module 10, and it may be provided on any side surface of the +X2 side, -X2 side, +Y2 side, or -Y2 side of the head drive module 10. Further, the operation of the cooling fan 770 to introduce outside air into the head drive module 10 does not necessarily mean that the cooling fan 770 only operates to take in outside air into the head drive module 10, and it also includes the case where the cooling fan 770 operates to discharge the air floating inside the head drive module 10.

[0233] In the liquid ejection device 1 configured as described above, the piezoelectric element 60 included in the ejection module 23-1 is an example of a first piezoelectric element, and the ejection unit 600 included in the ejection module 23-1 that ejects ink in response to the driving of the first piezoelectric element is an example of a first ejection unit. And the ejection module 23-1 having a plurality of ejection units 600 including the ejection unit 600 corresponding to the first ejection unit is an example of a first ejection unit group. Also, the piezoelectric element 60 included in the ejection module 23-2 is an example of a second piezoelectric element, and the ejection unit 600 included in the ejection module 23-2 that ejects ink in response to the driving of the second piezoelectric element is an example of a second ejection unit. And the ejection module 23-2 having a plurality of ejection units 600 including the ejection unit 600 corresponding to the second ejection unit is an example of a second ejection unit group. And the liquid ejection module 20 including the ejection modules 23-1 and 23-2 is an example of an ejection head. And the head drive module 10 that drives the liquid ejection module 20 corresponds to a head drive circuit.

[0234] Further, the drive signal COMA1 for driving 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 fifth drive signal, the drive signal COMC1 is an example of a second 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 fifth drive circuit, and the drive circuit 52c1 that outputs the drive signal COMC1 is an example of a second drive circuit. When the drive signal COMA1 is supplied to the piezoelectric element 60, the amount of ink ejected is an example of a first ejection amount. The amount of ink ejected when the drive signal COMB1 is supplied to the piezoelectric element 60 is less than the first ejection amount and is an example of a third ejection amount. The amount of current generated along with the propagation of the drive signal COMA1 is an example of a first current amount, and is smaller than the first current amount. The amount of current generated along with the propagation of the drive signal COMC1 is an example of a second current amount.

[0235] Also, the drive signal COMA2 for driving the piezoelectric element 60 included in the ejection module 23-2 is an example of a third drive signal, the drive signal COMB2 is an example of a sixth drive signal, the drive signal COMC2 is an example of a fourth drive signal, the drive circuit 52a2 that outputs the drive signal COMA2 is an example of a third drive circuit, the drive circuit 52b2 that outputs the drive signal COMB2 is an example of a sixth drive circuit, and the drive circuit 52c2 that outputs the drive signal COMC2 is an example of a fourth drive circuit. When the drive signal COMA2 is supplied to the piezoelectric element 60, the amount of ink ejected is an example of a second ejection amount. 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. The amount of current generated along with the propagation of the drive signal COMA2 is an example of a third current amount, and is smaller than the third current amount. The amount of current generated along with the propagation of the drive signal COMC2 is an example of a fourth current amount.

[0236] Further, the wiring board 810 provided with the drive circuits 52a1, 52b1, 52c1, 52a2, 52b2, 52c2 is an example of a board. In the wiring board 810, the X2 direction in which the drive circuits 52a1, 52b1, 52c1, 52a2, 52b2, 52c2 are arranged is an example of a direction.

[0237] 1.6 Effects In the liquid ejection device 1 of the first embodiment configured as described above, the head drive module 10 includes a drive circuit 52a1 that outputs a drive signal COMA1 for driving the piezoelectric element 60 so that the liquid ejection module 20 ejects a large amount of ink, a drive circuit 52b1 that outputs a drive signal COMB1 for driving the piezoelectric element 60 so that the liquid ejection module 20 ejects a small amount of ink, a drive circuit 52c1 that outputs a drive signal COMC1 for driving the piezoelectric element 60 so that the liquid ejection module 20 does not eject ink, a wiring board 810 that is arranged side by side in the X2 direction in the order of the drive circuit 52a1, the drive circuit 52b1, and the drive circuit 52c1, and a heat sink 710 attached to the wiring board 810.

[0238] In such a head drive module 10, the heat generation of the drive circuits 52a1 and 52b1 that output the drive signals COMA1 and COMB1 for driving the piezoelectric element 60 so that the liquid ejection module 20 ejects ink is greater than the heat generation of the drive circuit 52c1 that outputs the drive signal COMC1 for driving the piezoelectric element 60 so that the liquid ejection module 20 does not eject ink. A through hole 820 through which a screw 780 for attaching the heat sink 710 to the wiring board 810 is inserted is located between the drive circuit 52a1 and the drive circuit 52b1 with large heat generation. Thus, among the heat generated in the drive circuit 52a1 and the drive circuit 52b1, the heat conducted to the wiring board 810 is released to the heat sink 710 via the screw 780. As a result, the heat generated in the head drive module 10 can be released more efficiently.

[0239] In addition, when the head drive module 10 includes, in addition to the drive circuits 52a1, 52b1, and 52c1, drive circuits 52a2 and 52b2 that output drive signals COMA2 and COMB2 for driving the piezoelectric element 60 so that the liquid discharge module 20 discharges ink, and a drive circuit 52c2 that outputs a drive signal COMC2 for driving the piezoelectric element 60 so that the liquid discharge module 20 does not discharge ink, in addition to between the drive circuit 52a1 and the drive circuit 52b1, between the drive circuit 52a2 and the drive circuit 52b2, and between the drive circuit 52b1 and the drive circuit 52a2, through holes 820 through which screws 780 for attaching the heat sink 710 to the wiring board 810 are inserted are positioned. Thus, among the heat generated in the drive circuit 52a1, the drive circuit 52b1, the drive circuit 52a2, and the drive circuit 52b2, the heat conducted to the wiring board 810 can be released to the heat sink 710 via the screws 780. That is, even when the head drive module 10 has a plurality of sets of drive circuits 52 that supply the drive signal COM to different piezoelectric elements 60, the heat generated in the head drive module 10 can be released more efficiently.

[0240] Furthermore, in the liquid discharge device 1 of the present embodiment, in the head drive module 10, among the heat generated in the plurality of drive circuits 52, since the heat conducted to the wiring board 810 can also be efficiently conducted to the heat sink 710, even if the transistors M1 and M2 included in the drive circuit 52 are surface mount types that conduct a lot of heat to the wiring board 810, the heat generated by the drive circuit 52 can be efficiently conducted to the heat sink 710.

[0241] Also, in the liquid ejection device 1 of the first embodiment, the head drive module 10 includes a drive circuit 52a1 that outputs a drive signal COMA1 for driving the piezoelectric element 60 included in the ejection module 23-1 so that ink is ejected from the corresponding ejection portion 600, a drive circuit 52c1 that outputs a drive signal COMC1 for driving the piezoelectric element 60 included in the ejection module 23-1 so that ink is not ejected from the corresponding ejection portion 600, a drive circuit 52a2 that outputs a drive signal COMA2 for driving the piezoelectric element 60 included in the ejection module 23-2 so that ink is ejected from the corresponding ejection portion 600, and a drive circuit 52c2 that outputs a drive signal COMC2 for driving the piezoelectric element 60 included in the ejection module 23-2 so that ink is not ejected from the corresponding ejection portion 600.

[0242] Here, the voltage amplitude of the drive signal COMA1 output by the drive circuit 52a1 is larger than the voltage amplitude of the drive signal COMC1 for driving the piezoelectric element 60 included in the ejection module 23-1 so that ink is not ejected from the corresponding ejection portion 600 because it drives the piezoelectric element 60 included in the ejection module 23-1 so that ink is ejected from the corresponding ejection portion 600. Similarly, the voltage amplitude of the drive signal COMA2 output by the drive circuit 52a2 is larger than the voltage amplitude of the drive signal COMC2 for driving the piezoelectric element 60 included in the ejection module 23-2 so that ink is not ejected from the corresponding ejection portion 600 because it drives the piezoelectric element 60 included in the ejection module 23-2 so that ink is ejected from the corresponding ejection portion 600. Therefore, the heat generation amount of the drive circuit 52a1 is larger than the heat generation amount of the drive circuit 52c1, and the heat generation amount of the drive circuit 52a2 is larger than the heat generation amount of the drive circuit 52c2. That is, the liquid ejection device 1 of the first embodiment includes drive circuits 52a1, 52c1, 52a2, and 52c2 having different heat generation amounts as the plurality of drive circuits 52.

[0243] In such a liquid ejection device 1 of the first embodiment, the drive circuit 52a2 is located between the drive circuit 52a1 and the drive circuit 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 such that the shortest distance between the drive circuit 52c2 and the drive circuit 52c1 is shorter than the shortest distance between the drive circuit 52c2 and the drive circuit 52a2. That is, the drive circuits 52a1, 52c1, 52a2, and 52c2 are arranged in the order of drive circuits 52a1, 52a2, 52c1, and 52c2 in the direction along the X2 direction of the wiring board 810. In other words, on the wiring board 810, the drive circuits 52a1 and 52a2 with a large heat generation amount are arranged in the vicinity, and the drive circuits 52c1 and 52c2 with a small heat generation amount are arranged in the vicinity. Thereby, in the head drive module 10, it becomes easy to intensively arrange heat dissipation members such as the heat sink 710 for releasing the heat of the drive circuit 52 to the drive circuits 52a1 and 52a2 with a large heat generation amount. Further, it is possible to easily select whether or not to arrange the heat dissipation member for the drive circuits 52c1 and 52c2 with a small heat generation amount according to the usage environment and operating conditions of the liquid ejection device 1. That is, in the liquid ejection device 1 of the first embodiment, by arranging the drive circuits 52 with a large heat generation amount together on the wiring board 810 and arranging the drive circuits 52 with a small heat generation amount together on the wiring board 810, while reducing the possibility that the structure of the heat dissipation member such as the heat sink 710 for dissipating heat from a large number of drive circuits 52 becomes complicated, it is possible to appropriately select whether or not to arrange the heat dissipation member according to the heat generation amount generated by the large number of drive circuits 52. Thereby, even when the liquid ejection device 1 includes a large number of drive circuits 52, an optimal heat dissipation structure corresponding to the amount of heat generated by the large number of drive circuits 52 can be applied, and the heat generated by the large number of drive circuits 52 can be efficiently dissipated.

[0244] In the liquid ejection device 1 of the first embodiment, the head drive module 10 includes a drive circuit 52b1 that outputs a drive signal COMB1 for driving the piezoelectric element 60 included in the ejection module 23-1 so that ink is ejected from the corresponding ejection unit 600, and a drive circuit 52a2 that outputs a drive signal COMB2 for driving the piezoelectric element 60 included in the ejection module 23-2 so that ink is ejected from the corresponding ejection unit 600. As a result, the ejection amount of the ink ejected from the ejection module 23-1 can be controlled by the drive signals COMA1 and COMB1, and similarly, the ejection amount of the ink ejected from the ejection module 23-2 can be controlled by the drive signals COMA2 and COMB2. That is, more detailed control of the ejection amount of the ink ejected from each of the ejection modules 23-1 and 23-2 becomes possible, and the image quality formed on the medium is improved.

[0245] In such a liquid ejection device 1 of the first embodiment, the voltage amplitude of the drive signal COMB1 output by the drive circuit 52b1 is larger than the voltage amplitude of the drive signal COMC1 for driving so that ink is not ejected from the ejection unit 600 corresponding to the piezoelectric element 60 included in the ejection module 23-1 because it drives so that ink is ejected from the ejection unit 600 corresponding to the piezoelectric element 60 included in the ejection module 23-1. Similarly, the voltage amplitude of the drive signal COMB2 output by the drive circuit 52b2 is larger than the voltage amplitude of the drive signal COMC2 for driving so that ink is not ejected from the ejection unit 600 corresponding to the piezoelectric element 60 included in the ejection module 23-2 because it drives so that ink is ejected from the ejection unit 600 corresponding to the piezoelectric element 60 included in the ejection module 23-2. Therefore, the heat generation amount of the drive circuit 52b1 is larger than the heat generation amount of the drive circuit 52c1, and the heat generation amount of the drive circuit 52b2 is larger than the heat generation amount of the drive circuit 52c2.

[0246] In the liquid ejection device 1 according to the first embodiment, when the liquid ejection device 1 includes a drive circuit 52b1 that outputs a drive signal COMB1 for driving the piezoelectric element 60 included in the ejection module 23-1 so that ink is ejected from the corresponding ejection unit 600, and a drive circuit 52a2 that outputs a drive signal COMB2 for driving the piezoelectric element 60 included in the ejection module 23-2 so that ink is ejected from the corresponding ejection unit 600, along the X2 direction, the drive circuits 52b1 and 52b2 are positioned between the drive circuit 52a1 and the drive circuit 52c1, and are also positioned between the drive circuit 52a1 and the drive circuit 52c2. That is, the drive circuits 52b1, 52b2 with a large heat generation amount are not arranged between the drive circuits 52c1, 52c2 with a small heat generation amount.

[0247] Accordingly, even when the liquid ejection device 1 includes the drive circuit 52b1 that outputs the drive signal COMB1 for driving the piezoelectric element 60 included in the ejection module 23-1 so that ink is ejected from the corresponding ejection unit 600, and the drive circuit 52a2 that outputs the drive signal COMB2 for driving the piezoelectric element 60 included in the ejection module 23-2 so that ink is ejected from the corresponding ejection unit 600, the drive circuits 52 with a large heat generation amount can be collectively arranged on the wiring board 810, and the drive circuits 52 with a small heat generation amount can be collectively arranged on the wiring board 810. Thereby, while reducing the possibility that the structure of a heat dissipation member such as the heat sink 710 for dissipating heat from the drive circuit 52 becomes complicated, it is possible to appropriately select whether to arrange according to the heat generation amount generated by a large number of drive circuits 52. As a result, even when the liquid ejection device 1 includes a large number of drive circuits 52, the heat generated by the large number of drive circuits 52 can be efficiently dissipated.

[0248] In the liquid ejection device 1 according to the first embodiment, the drive circuit 52a1 and the drive circuit 52b1 that output the drive signals COMA1 and COMB1 supplied to the ejection module 23-1 are adjacent to each other on the wiring board 810, and the drive circuit 52a2 and the drive circuit 52b2 that output the drive signals COMA2 and COMB2 supplied to the ejection module 23-2 are adjacent to each other on the wiring board 810. As a result, the difference in the wiring lengths through which the drive signal COMA1 supplied to the ejection module 23-1 propagates and the wiring length through which the drive signal COMB1 propagates can be reduced. Similarly, the difference in the wiring lengths through which the drive signal COMA2 supplied to the ejection module 23-2 propagates and the wiring length through which the drive signal COMB2 propagates can be reduced. As a result, the possibility of a time difference due to signal propagation occurring between the drive signal COMA1 and the drive signal COMB1 for ejecting ink from the ejection module 23-1 is reduced. Similarly, the possibility of a time difference due to signal propagation occurring between the drive signal COMA2 and the drive signal COMB2 for ejecting ink from the ejection module 23-2 is reduced. Therefore, the ejection accuracy of the ink ejected from the ejection modules 23-1 and 23-2 is further improved.

[0249] Also, in the liquid ejection device 1 of the first embodiment, the drive circuit board 800 included in the head drive module 10 includes a drive circuit 52a1 that outputs a drive signal COMA1 for driving the piezoelectric element 60 so that the ejection unit 600 included in the ejection module 23-1 ejects a large amount of ink, a drive circuit 52c1 that outputs a drive signal COMC1 for driving the piezoelectric element 60 so that the ejection unit 600 included in the ejection module 23-1 does not eject ink, a drive circuit 52a6 that outputs a drive signal COMA6 for driving the piezoelectric element 60 so that the ejection unit 600 included in the ejection module 23-6 ejects a large amount of ink, and a drive circuit 52a6 that outputs a drive signal COMC6 for driving the piezoelectric element 60 so that the ejection unit 600 included in the ejection module 23-6 does not eject ink. The head drive module 10 further includes a connection part CN2 that electrically connects the head drive module 10 and the liquid ejection module 20, and a wiring board 810 on which the plurality of drive circuits 52 and the connection part CN2 are provided. The wiring board 810 includes a wiring WA1 that propagates the drive signal COMA1 from the drive circuit 52a1 to the connection part CN2, a wiring WC1 that propagates the drive signal COMC1 from the drive circuit 52c1 to the connection part CN2, a wiring WA6 that propagates the drive signal COMA6 from the drive circuit 52a6 to the connection part CN2, and a wiring WA6 that propagates the drive signal COMC6 from the drive circuit 52a6 to the connection part CN2. Further, the wiring board 810 includes a plurality of wiring patterns that electrically connect each of the plurality of drive circuits 52 and the connection part CN2. In such a head drive module 10, the drive circuits 52a1, 52c1, 52a6, and 52c6 are provided on the wiring board 810 such 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.

[0250] Here, the drive signal COMA1 drives the piezoelectric element 60 so that the ejection unit 600 included in 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 included in the ejection module 23-1 does not eject ink. Therefore, the amount of current generated when the drive signal COMA1 propagates is larger than the amount of current generated when the drive signal COMC1 propagates. Also, the drive signal COMA6 drives the piezoelectric element 60 so that the ejection unit 600 included in 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 included in the ejection module 23-6 does not eject ink. Therefore, the amount of current generated when the drive signal COMA6 propagates is larger than the amount of current generated when the drive signal COMC6 propagates. That is, in the liquid ejection apparatus 1 according to the first embodiment, the wiring length through which a signal with a large amount of current generated when the drive signal COM propagates is shorter than the wiring length through which a signal with a small amount of current generated when the signal propagates. As a result, the influence of the impedance component of the wirings WA1 and WA6 through which the drive signals COMA1 and COMA that can generate a large current during propagation propagate is reduced, and as a result, the possibility that a voltage drop due to the impedance component of the wirings WA1 and WA6 occurs in the drive signals COMA1 and COMA6 is reduced. That is, the waveform accuracy of the drive signals COMA1 and COMA6 supplied to the liquid ejection module 20 is improved. As a result, the ink ejection accuracy in the ejection modules 23-1 and 23-6 included in the liquid ejection module 20 is improved.

[0251] Also, 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 for driving the piezoelectric element 60 so that the ejection unit 600 included in the ejection module 23-1 ejects a small amount of ink, and a drive circuit 52b6 that outputs a drive signal COMB6 for driving the piezoelectric element 60 so that the ejection unit 600 included in the ejection module 23-6 ejects a small amount of ink. The wiring board 810 includes a wiring WB1 that propagates the drive signal COMB1 from the drive circuit 52b1 to the connection portion CN2, and a wiring WB6 that propagates the drive signal COMB6 from the drive circuit 52b6 to the connection portion CN2. In the head drive module 10, the drive circuit 52b1 is provided on the wiring board 810 such 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 such that the wiring WB6 is longer than the wiring WA6 and shorter than the wiring WC6.

[0252] When the drive signal COMB1 is propagated, the amount of current generated 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 piezoelectric element 60 is driven so that the ejection unit 600 included in the ejection module 23-1 ejects a small amount of ink. Also, when the drive signal COMB6 is propagated, the amount of current generated 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 piezoelectric element 60 is driven so that the ejection unit 600 included in the ejection module 23-6 ejects a small amount of ink. In such a head drive module 10, the drive circuit 52b1 is provided on the wiring board 810 such 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 such that the wiring WB6 is longer than the wiring WA6 and shorter than the wiring WC6. Thus, even when the head drive module 10 includes the drive circuit 52b1 that outputs the drive signal COMB1 and the drive circuit 52b6 that outputs the drive signal COMB6, it is possible to reduce the possibility that a voltage drop due to the impedance component of the wirings WA1 and WA6 occurs in the drive signals COMA1 and COMA6, and it is possible to reduce the possibility that a voltage drop due to the impedance component of the wirings WB1 and WB6 occurs in the drive signals COMB1 and COMB6. As a result, the ejection accuracy of the ink in the ejection modules 23-1 and 23-6 included in the liquid ejection module 20 is improved.

[0253] 2. Second Embodiment Next, the liquid ejection device 1 of the second embodiment will be described. In describing the liquid ejection device 1 of the second embodiment, the same components as those of the liquid ejection device 1 of the first embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted. In the liquid ejection device 1 of the second embodiment, the arrangement of the plurality of drive circuits 52 provided on the wiring board 810 is different from that of the liquid ejection device 1 of the first embodiment.

[0254] FIG. 18 is a diagram showing an example of the configuration of the first layer 831 of the wiring board 810 included in the liquid ejection device 1 of the second embodiment. As shown in FIG. 18, in the liquid ejection device 1 of the second embodiment, the plurality of drive circuits 52 are located between the integrated circuit 101 and the connection portion CN2 and are arranged side by side along the X2 direction.

[0255] 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 adjacent to each other along the X2 direction. 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 adjacent to each other along the X2 direction. The drive circuit 52a3 and a drive circuit 52a4 that outputs a drive signal COMA4 for driving the piezoelectric element 60 so that a large amount of ink is ejected from the ejection module 23-4 are adjacent to each other along the X2 direction. The drive circuit 52a4 and a drive circuit 52a5 that outputs a drive signal COMA5 for driving the piezoelectric element 60 so that a large amount of ink is ejected from the ejection module 23-5 are adjacent to each other along the X2 direction. The drive circuit 52a5 and a drive circuit 52a6 that outputs a drive signal COMA6 for driving the piezoelectric element 60 so that a large amount of ink is ejected from the ejection module 23-6 are adjacent to each other along the X2 direction.

[0256] Also, a 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 a 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 adjacent to each other along the X2 direction. The drive circuit 52b2 and a 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 adjacent to each other along the X2 direction. The drive circuit 52b3 and a drive circuit 52b4 that outputs a drive signal COMB4 for driving the piezoelectric element 60 so that a small amount of ink is ejected from the ejection module 23-4 are adjacent to each other along the X2 direction. The drive circuit 52b4 and a drive circuit 52b5 that outputs a drive signal COMB5 for driving the piezoelectric element 60 so that a small amount of ink is ejected from the ejection module 23-5 are adjacent to each other along the X2 direction. The drive circuit 52b5 and a drive circuit 52b6 that outputs a drive signal COMB6 for driving the piezoelectric element 60 so that a small amount of ink is ejected from the ejection module 23-6 are adjacent to each other along the X2 direction.

[0257] That is, in the head drive module 10, drive circuits 52a1 to 52a6 that output drive signals COMA1 to COMA6 for driving the piezoelectric element 60 so that a large amount of ink is ejected are adjacent to each other in the first layer 831 of the wiring board 810, and drive circuits 52b1 to 52b6 that output drive signals COMB1 to COMB6 for driving the piezoelectric element 60 so that a small amount of ink is ejected are adjacent to each other in the first layer 831 of the wiring board 810.

[0258] And drive circuits 52c1 to 52c6 that output drive signals COMC1 to COMC6 for driving piezoelectric element 60 so as not to eject ink are arranged in order of drive circuits 52c1, 52c2, 52c3, 52c4, 52c5, 52c6 along the X2 direction from side 812 to side 811 on the side 811 of wiring board 810 with respect to drive circuits 52b1 to 52b6.

[0259] That is, in liquid ejection device 1 of the second embodiment, drive circuits 52a1 to 52a6 with a very large amount of heat generation because they eject a large amount of ink are collectively arranged in the first layer 831 of wiring board 810, drive circuits 52b1 to 52b6 with a large amount of heat generation because they eject a small amount of ink are collectively arranged in the first layer 831 of wiring board 810, and drive circuits 52c1 to 52c6 with an even smaller amount of heat generation are collectively arranged in the first layer 831 of wiring board 810. Thereby, similar to liquid ejection device 1 of the first embodiment, while reducing the possibility that the structure of heat dissipation members such as heat sink 710 for dissipating heat from a large number of drive circuits 52 becomes complicated, it is possible to appropriately select whether to arrange according to the amount of heat generated by a large number of drive circuits 52. As a result, even when liquid ejection device 1 includes a large number of drive circuits 52, the heat generated by the large number of drive circuits 52 can be efficiently dissipated.

[0260] Next, an example of the configuration of the wiring patterns through which drive signals COMA1 to COMA6, COMB1 to COMB6, and COMC1 to COMC6 propagate in 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 in the second layer 832 of wiring board 810 of the second embodiment. FIG. 20 is a diagram showing an example of the wiring pattern provided in the third layer 833 of wiring board 810 of the second embodiment. FIG. 21 is a diagram showing an example of the wiring pattern provided in the fourth layer 834 of wiring board 810 of the second embodiment.

[0261] As shown in Fig. 18, in the liquid ejection device 1 of the second embodiment, the drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 as a plurality of drive circuits 52 are arranged in the first layer 831 of the wiring board 810 in the order of drive circuits 52a1, 52a2, 52a3, 52a4, 52a5, 52a6, 52b1, 52b2, 52b3, 52b4, 52b5, 52b6, 52c1, 52c2, 52c3, 52c4, 52c5, 52c6 from the -X2 side to the +X2 side along the X2 direction. 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 for driving so that a large amount of ink is ejected from the piezoelectric elements 60 included in the ejection modules 23-1 to 23-6 from the corresponding nozzles N are collectively located in the vicinity of the connection portion CN2, and the drive circuits 52b1 to 52b6 that output drive signals COMB1 to COMB6 for driving so that a small amount of ink is ejected from the piezoelectric elements 60 included in the ejection modules 23-1 to 23-6 from the corresponding nozzles N are collectively located farther from the connection portion CN2 than the drive circuits 52a1 to 52a6, and the drive circuits 52c1 to 52c6 that output drive signals COMC1 to COMC6 for driving so that no ink is ejected from the piezoelectric elements 60 included in the ejection modules 23-1 to 23-6 from the corresponding nozzles N are collectively located farther from the connection portion CN2 than the drive circuits 52b1 to 52b6.

[0262] As a result, in the liquid ejection device 1 of the second embodiment, as shown in FIGS. 19 to 21, the wiring lengths of the wirings WA1 to WA6 that electrically connect each of the drive circuits 52a1 to 52a6 to the connection portion CN2 and propagate the drive signals COMA1 to COMA6 can be made shorter than the wiring lengths of the wirings WB1 to WB6 that electrically connect each of the drive circuits 52b1 to 52b6 to the connection portion CN2 and propagate the drive signals COMB1 to COMB6, and the wiring lengths of the wirings WA1 to WA6, WB1 to WB6 that electrically connect each of the drive circuits 52a1 to 52a6, 52b1 to 52b6 to the connection portion 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 to 52c6 to the connection portion CN2 and propagate the drive signals COMC1 to COMC6.

[0263] As described above, in the head drive module 10, the voltage amplitudes of the drive signals COMA1 to COMA6 are larger than the voltage amplitudes of the drive signals COMB1 to COMB6 that 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 because the piezoelectric element 60 is driven so that a large amount of ink is ejected from the nozzles N of the ejection modules 23-1 to 23-6, and the voltage amplitudes of the drive signals COMA1 to COMA6, COMB1 to COMB6 are larger than the voltage amplitudes of the drive signals COMC1 to COMC6 that drive the piezoelectric element 60 so that ink is not ejected from the nozzles N of the ejection modules 23-1 to 23-6 because the piezoelectric element 60 is driven so that ink is ejected from the nozzles N of the ejection modules 23-1 to 23-6.

[0264] That is, the current amount generated due to the propagation of drive signals COMA1 to COMA6 is larger than the current amount generated due to the propagation of drive signals COMB1 to COMB6 and COMC1 to COMC6, and the current amount generated due to the propagation of drive signals COMB1 to COMB6 is larger than the current amount generated due to the propagation of drive signals COMC1 to COMC6. Therefore, compared with drive signals COMB1 to COMB6 and COMC1 to COMC6, drive signals COMA1 to COMA6 are more susceptible to the influence of impedance generated in the wiring pattern, and compared with drive signals COMC1 to COMC6, drive signals COMB1 to COMB6 are more susceptible to the influence of impedance generated in the wiring pattern. By making the wiring lengths of wirings WA1 to WA6 through which drive signals COMA1 to COMA6 propagate shorter than the wiring lengths of wirings WB1 to WB6 and WC1 to WC6 through which drive signals COMB1 to COMB6 and COMC1 to COMC6 propagate, and making the wiring lengths of wirings WB1 to WB6 through which drive signals COMB1 to COMB6 propagate shorter than the wiring lengths of wirings WC1 to WC6 through which drive signals COMC1 to COMC6 propagate, the waveform accuracy of drive signals COMA1 to COMA6 can be further improved compared with the liquid discharge device 1 of the first embodiment.

[0265] Also, as shown in FIG. 18, in the liquid ejection device 1 according to the second embodiment, some of the plurality of through holes 820 through which the 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, between the adjacent drive circuits 52a5 and 52a6, between the adjacent drive circuits 52a6 and 52b1, between the adjacent drive circuits 52b1 and 52b2, between the adjacent drive circuits 52b2 and 52b3, between the adjacent drive circuits 52b3 and 52b4, between the adjacent drive circuits 52b4 and 52b5, and between the adjacent drive circuits 52b5 and 52b6.

[0266] That is, when the heat sink 710 is attached to the wiring board 810, the screws 780 are located between each of the drive circuits 52a1 to 52a6 and the drive circuits 52b1 to 52b6 provided side by side on the wiring board 810. Thus, similar to the liquid ejection device 1 of the first embodiment, among the heat generated in the drive circuits 52a1 to 52a6 and the drive circuits 52b1 to 52b6 with a large amount of heat generation, the heat conducted to the wiring board 810 can be released to the heat sink 710 via the screws 780, and efficient release of the heat generated in the head drive module 10 can be achieved.

[0267] 3. Third Embodiment Next, the liquid ejection device 1 of the third embodiment will be described. In describing the liquid ejection device 1 of the third embodiment, the same components as those of the liquid ejection devices 1 of the first and second embodiments are denoted by the same reference numerals, and the description thereof will be simplified or omitted. In the liquid ejection device 1 of the third embodiment, the arrangement of the plurality of drive circuits 52 provided on the wiring substrate 810 is different from that of the liquid ejection devices 1 of the first and second embodiments. FIG. 22 is a diagram showing an example of the configuration of the first layer 831 when the wiring substrate 810 of the third embodiment is viewed from the Z2 side along the Z2 direction. FIG. 23 is a diagram showing an example of the wiring pattern provided on the second layer 832 of the wiring substrate 810 of the third embodiment. FIG. 24 is a diagram showing an example of the wiring pattern provided on the third layer 833 of the wiring substrate 810 of the third embodiment. FIG. 25 is a diagram showing an example of the wiring pattern provided on the fourth layer 834 of the wiring substrate 810 of the third embodiment.

[0268] As shown in FIG. 22, in the liquid ejection device 1 of the third embodiment, the drive circuits 52a1 to 52a6, 52b1 to 52b6, and 52c1 to 52c6 as a plurality of drive circuits 52 are arranged in the first layer 831 of the wiring board 810 in the order of drive circuits 52a1, 52b1, 52c1, 52a2, 52b2, 52c2, 52a3, 52b3, 52c3, 52a4, 52b4, 52c4, 52a5, 52b5, 52c5, 52a6, 52b6, 52c6 from the -X2 side to the +X2 side along the X2 direction. That is, in the liquid ejection device 1 of the third embodiment, the drive circuits 52a1, 52b1, and 52c1 that output drive signals COMA1, COMB1, and COMC1 for driving the piezoelectric element 60 included in the ejection module 23-1 are located in the vicinity of the connection portion CN2, and on the +X2 side of the drive circuits 52a1, 52b1, and 52c2, the drive circuits 52a2, 52b2, and 52c2 that output drive signals COMA2, COMB2, and COMC2 for driving the piezoelectric element 60 included in the ejection module 23-2 are located. On the +X2 side of the drive circuits 52a2, 52b2, and 52c2, the drive circuits 52a3, 52b3, and 52c3 that output drive signals COMA3, COMB3, and COMC3 for driving the piezoelectric element 60 included in the ejection module 23-3 are located. On the +X2 side of the drive circuits 52a3, 52b3, and 52c3, the drive circuits 52a4, 52b4, and 52c4 that output drive signals COMA4, COMB4, and COMC4 for driving the piezoelectric element 60 included in the ejection module 23-4 are located. On the +X2 side of the drive circuits 52a4, 52b4, and 52c4, the drive circuits 52a5, 52b5, and 52c5 that output drive signals COMA5, COMB5, and COMC5 for driving the piezoelectric element 60 included in the ejection module 23-5 are located. On the +X2 side of the drive circuits 52a5, 52b5, and 52c5, the drive circuits 52a6, 52b6, and 52c6 that output drive signals COMA6, COMB6, and COMC6 for driving the piezoelectric element 60 included in the ejection module 23-6 are located.

[0269] As a result, as shown in FIGS. 23 to 25, the driving circuit 52a1 and the connection portion CN2 are electrically connected, and the wiring length of the wiring WA1 that propagates the driving signal COMA1 can be made shorter than the wiring length of the wiring WB1 that electrically connects the driving circuit 52b1 and the connection portion CN2 and propagates the driving signal COMB1. Also, the wiring lengths of the wirings WA1 and WB1 can be made shorter than the wiring length of the wiring WC1 that electrically connects the driving circuit 52c1 and the connection portion CN2 and propagates the driving signal COMC1.

[0270] Similarly, the driving circuit 52a2 and the connection portion CN2 are electrically connected, and the wiring length of the wiring WA2 that propagates the driving signal COMA2 can be made shorter than the wiring length of the wiring WB2 that electrically connects the driving circuit 52b2 and the connection portion CN2 and propagates the driving signal COMB2. Also, the wiring lengths of the wirings WA2 and WB2 can be made shorter than the wiring length of the wiring WC2 that electrically connects the driving circuit 52c2 and the connection portion CN2 and propagates the driving signal COMC2.

[0271] Similarly, the driving circuit 52a3 and the connection portion CN2 are electrically connected, and the wiring length of the wiring WA3 that propagates the driving signal COMA3 can be made shorter than the wiring length of the wiring WB3 that electrically connects the driving circuit 52b3 and the connection portion CN2 and propagates the driving signal COMB3. Also, the wiring lengths of the wirings WA3 and WB3 can be made shorter than the wiring length of the wiring WC3 that electrically connects the driving circuit 52c3 and the connection portion CN2 and propagates the driving signal COMC3.

[0272] Similarly, the driving circuit 52a4 and the connection portion CN2 are electrically connected, and the wiring length of the wiring WA4 that propagates the driving signal COMA4 can be made shorter than the wiring length of the wiring WB4 that electrically connects the driving circuit 52b4 and the connection portion CN2 and propagates the driving signal COMB4. Also, the wiring lengths of the wirings WA4 and WB4 can be made shorter than the wiring length of the wiring WC4 that electrically connects the driving circuit 52c4 and the connection portion CN2 and propagates the driving signal COMC4.

[0273] Similarly, the wiring length of the wiring WA5 that electrically connects the drive circuit 52a5 and the connection part CN2 and propagates the drive signal COMA5 can be made shorter than the wiring length of the wiring WB5 that electrically connects the drive circuit 52b5 and the connection part CN2 and propagates the drive signal COMB5, and the wiring lengths of the wirings WA5 and WB5 can be made shorter than the wiring length of the wiring WC5 that electrically connects the drive circuit 52c5 and the connection part CN2 and propagates the drive signal COMC5.

[0274] Similarly, the wiring length of the wiring WA6 that electrically connects the drive circuit 52a6 and the connection part CN2 and propagates the drive signal COMA6 can be made shorter than the wiring length of the wiring WB6 that electrically connects the drive circuit 52b6 and the connection part CN2 and propagates the drive signal COMB6, and the wiring lengths of the wirings WA6 and WB6 can be made shorter than the wiring length of the wiring WC6 that electrically connects the drive circuit 52c6 and the connection part CN2 and propagates the drive signal COMC6.

[0275] As a result, for each ejection module 23, the wiring lengths of the wirings WA1 to WA6 through which the drive signals COMA1 to COMA6, which are liable to be affected by the impedance generated in the wiring pattern, propagate are made shorter than the wiring lengths of the wirings WB1 to WB6 and WC1 to WC6 through which the drive signals COMB1 to COMB6 and COMC1 to COMC6 propagate, and the wiring lengths of the wirings WB1 to WB6 through which the drive signals COMB1 to COMB6 propagate can be made shorter than the wiring lengths of the wirings WC1 to WC6 through which the drive signals COMC1 to COMC6 propagate, thereby improving the ejection accuracy of the ink for each ejection module 23.

[0276] Furthermore, in the liquid ejection device 1 according to 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, and the supply error that may occur due to the difference in wiring length in the drive signals COMA1, COMB1, and COMC1 supplied to the ejection module 23-1 can be reduced.

[0277] Similarly, the difference in length between the wiring WA2 that supplies the drive signal COMA2 to the ejection module 23-2, the wiring WB2 that supplies the drive signal COMB2, and the wiring WC2 that supplies the drive signal COMC2 can be reduced. The difference in length between the wiring WA3 that supplies the drive signal COMA3 to the ejection module 23-3, the wiring WB3 that supplies the drive signal COMB3, and the wiring WC3 that supplies the drive signal COMC3 can be reduced. The difference in length between the wiring WA4 that supplies the drive signal COMA4 to the ejection module 23-4, the wiring WB4 that supplies the drive signal COMB4, and the wiring WC4 that supplies the drive signal COMC4 can be reduced. The difference in length between the wiring WA5 that supplies the drive signal COMA5 to the ejection module 23-5, the wiring WB5 that supplies the drive signal COMB5, and the wiring WC5 that supplies the drive signal COMC5 can be reduced. The difference in length between the wiring WA6 that supplies the drive signal COMA6 to the ejection module 23-6, the wiring WB6 that supplies the drive signal COMB6, and the wiring WC6 that supplies the drive signal COMC6 can be reduced.

[0278] As a result, the possibility of a timing difference caused by the wiring length in the signals input to the ejection modules 23-1 to 23-6 is reduced, and the ink ejection accuracy for each ejection module 23 is improved.

[0279] Also, as shown in FIG. 22, in the liquid ejection device 1 according to the third embodiment, some of the plurality of through holes 820 through which the screws 780 for attaching the heat sink 710 to the wiring board 810 are inserted are located between the adjacent drive circuits 52a1 and 52b1, between the adjacent drive circuits 52a2 and 52b2, between the adjacent drive circuits 52a3 and 52b3, between the adjacent drive circuits 52a4 and 52b4, between the adjacent drive circuits 52a5 and 52b5, and between the adjacent drive circuits 52a6 and 52b6.

[0280] That is, in the liquid ejection device 1 according to the third embodiment, the drive circuits 52a1 to 52a6, the drive circuits 52b1 to 52b6, and the drive circuits 52c1 to 52c6 are arranged side by side along the X2 direction on the wiring board 810 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 between the drive circuit 52a1 and the drive circuit 52b1, between the drive circuit 52a2 and the drive circuit 52b2, between the drive circuit 52a3 and the drive circuit 52b3, between the drive circuit 52a4 and the drive circuit 52b4, between the drive circuit 52a5 and the drive circuit 52b5, and between the drive circuit 52a6 and the drive circuit 52b6 in the X2 direction.

[0281] Even in the liquid ejection device 1 according to the third embodiment configured as described above, similar to the liquid ejection devices 1 of the first and second embodiments, among the heat generated by the drive circuits 52a1 to 52a6 and the drive circuits 52b1 to 52b6 with a large amount of heat generation, the heat conducted to the wiring board 810 can be released to the heat sink 710 via the screws 780, and efficient release of the heat generated in the head drive module 10 can be achieved.

[0282] Here, in the liquid ejection device 1 according to the third embodiment, as shown in FIG. 26, a plurality of through holes 820 through which the screws 780 for attaching the heat sink 710 to the wiring board 810 are inserted may be further provided between the drive circuit 52c1 and the drive circuit 52a2, between the drive circuit 52c2 and the drive circuit 52a3, between the drive circuit 52c3 and the drive circuit 52a4, between the drive circuit 52c4 and the drive circuit 52a5, and between the drive circuit 52c5 and the drive circuit 52a6 along the X2 direction. FIG. 26 is a diagram showing an example of the configuration of the first layer 831 when the wiring board 810 of a modified example of the third embodiment is viewed from the Z2 side along the Z2 direction.

[0283] In the liquid ejection device 1 according to the modified example of the third embodiment configured as described above, among the heat generated in the drive circuits 52a1 to 52a6 with particularly large calorific values, the heat conducted to the wiring board 810 can be released to the heat sink 710 via two screws 780, and the heat release efficiency of the heat generated in the head drive module 10 can be further enhanced.

[0284] Although the embodiments and modified examples have been described above, the present invention is not limited to these embodiments, and can be implemented in various aspects without departing from the gist thereof. For example, it is also possible to appropriately combine the above-described embodiments.

[0285] The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations having the same functions, methods, and results, or configurations having the same purposes and effects). Further, the present invention includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. Further, the present invention includes configurations that exhibit the same operational effects as the configurations described in the embodiments or configurations that can achieve the same purposes. Further, the present invention includes configurations in which known techniques are added to the configurations described in the embodiments.

[0286] The following content is derived from the above-described embodiments.

[0287] One aspect of the liquid ejection device is a first ejection unit group including a first ejection unit that includes a first piezoelectric element and ejects liquid in response to driving of the first piezoelectric element, and a second ejection unit group including a second ejection unit that includes a second piezoelectric element and ejects liquid in response to driving of the second piezoelectric element, a substrate, a first drive circuit, a second drive circuit, a third drive circuit, and a fourth drive circuit provided side by side along one direction of the substrate, and is provided with the first drive circuit outputs a first drive signal for driving the first piezoelectric element so that the first ejection unit ejects a liquid with a first ejection amount, The second drive circuit outputs a second drive signal for driving the first piezoelectric element so that the first discharge unit does not discharge liquid. The third drive circuit outputs a third drive signal for driving the second piezoelectric element so that the second discharge unit discharges a liquid of a second discharge amount. The fourth drive circuit outputs a fourth drive signal for driving the second piezoelectric element so that the second discharge unit does not discharge liquid. The third drive circuit is located between the first drive circuit and the second drive circuit along the one direction. The shortest distance between the fourth drive circuit and the second drive circuit is shorter than the shortest distance between the fourth drive circuit and the third drive circuit.

[0288] According to this liquid ejection device, the first drive signal drives the first piezoelectric element so that the first ejection unit ejects a liquid of a first ejection amount, and the second drive signal drives the first piezoelectric element so that the first ejection unit does not eject the liquid. Therefore, the voltage amplitude of the first drive signal is larger than the voltage amplitude of the second drive signal. Therefore, the heat generation occurring in the first drive circuit that outputs the first drive signal is larger than the heat generation occurring in the second drive circuit that outputs the second drive signal. Similarly, the third drive signal drives the second piezoelectric element so that the second ejection unit ejects a liquid of a second ejection amount, and the fourth drive signal drives the second piezoelectric element so that the second ejection unit does not eject the liquid. Therefore, the voltage amplitude of the third drive signal is larger than the voltage amplitude of the fourth drive signal. Therefore, the heat generation occurring in the third drive circuit that outputs the third drive signal is larger than the heat generation occurring in the fourth drive circuit that outputs the fourth drive signal. In this liquid ejection device, the first drive circuit, the second drive circuit, the third drive circuit, and the fourth drive circuit are provided side by side along one direction of the substrate. The third drive circuit is located between the first drive circuit and the second drive circuit along the one direction. The shortest distance between the fourth drive circuit and the second drive circuit is shorter than the shortest distance between the fourth drive circuit and the third drive circuit. That is, the first drive circuit with a large heat generation and the third drive circuit with a large heat generation are arranged in the vicinity on the substrate, and the second drive circuit with a small heat generation and the fourth drive circuit with a small heat generation are arranged in the vicinity on the substrate. In other words, the first drive circuit and the third drive circuit with a large heat generation on the substrate are collectively arranged, and the second drive circuit and the fourth drive circuit with a small heat generation are collectively arranged. Thereby, it is possible to concentrate and dissipate heat from the first drive circuit with a large heat generation and the third drive circuit with a large heat generation, and it is possible to appropriately select whether to provide a heat dissipation member for the second drive circuit with a small heat generation and the fourth drive circuit with a small heat generation according to the usage environment and operating state of the liquid ejection device. As a result, even when there are a large number of drive circuits including the first drive circuit, the second drive circuit, the third drive circuit, and the fourth drive circuit, an optimal heat dissipation structure corresponding to the amount of heat generated in the first drive circuit, the second drive circuit, the third drive circuit, and the fourth drive circuit can be applied, and the heat generated in the first drive circuit, the second drive circuit, the third drive circuit, and the fourth drive circuit can be efficiently dissipated.

[0289] In one aspect of the liquid ejection device, it includes a fifth drive circuit and a sixth drive circuit provided on the substrate, the fifth drive circuit outputs a fifth drive signal for driving the first piezoelectric element so that the first ejection portion ejects a liquid with a third ejection amount, the sixth drive circuit outputs a sixth drive signal for driving the second piezoelectric element so that the second ejection portion ejects a liquid with a fourth ejection amount, along the one direction, the fifth drive circuit and the sixth drive circuit may be located between the first drive circuit and the second drive circuit, and may also be located between the first drive circuit and the fourth drive circuit.

[0290] According to this liquid ejection device, there is provided a fifth drive circuit that outputs a fifth drive signal which, when supplied to the first piezoelectric element, causes the first ejection portion to eject a liquid with a third ejection amount different from the first ejection amount, and a sixth drive circuit that outputs a sixth drive signal which, when supplied to the second piezoelectric element, causes the second ejection portion to eject a liquid with a fourth ejection amount different from the second ejection amount. Even in a case where multi-tone image formation is possible by including these, the first drive circuit, the third drive circuit, the fifth drive circuit, and the sixth drive circuit that generate a large amount of heat can be concentrated for heat dissipation, and for the second drive circuit with low heat generation and the fourth drive circuit with low heat generation, it is possible to appropriately select whether to provide a heat dissipation member according to the usage environment and operating state of the liquid ejection device. Therefore, even when including a large number of drive circuits including 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, an optimal heat dissipation structure corresponding to the amount of heat generated in 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 can be applied, and the heat generated in 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 can be efficiently dissipated.

[0291] In one aspect of the liquid ejection device, along the one direction, the first drive circuit and the fifth drive circuit may be adjacent to each other, and the third drive circuit and the sixth drive circuit may be adjacent to each other.

[0292] According to this liquid ejection device, a first drive circuit that outputs a first drive signal to the first piezoelectric element and a fifth drive circuit that outputs a fifth drive signal to the first piezoelectric element are arranged adjacent to each other, and a third drive circuit that outputs a third drive signal to the second piezoelectric element and a sixth drive circuit that outputs a sixth drive signal to the second piezoelectric element are arranged adjacent to each other. Thus, it becomes possible to perform collective cooling for each ejection unit group including the piezoelectric element 60 to be driven. Even when the number of ejection unit groups included in the liquid ejection device increases, an optimal heat dissipation structure corresponding to the increased ejection unit groups can be applied.

[0293] Also, according to this liquid ejection device, a first drive circuit that outputs a first drive signal to the first piezoelectric element and a fifth drive circuit that outputs a fifth drive signal to the first piezoelectric element are arranged adjacent to each other, and a third drive circuit that outputs a third drive signal to the second piezoelectric element and a sixth drive circuit that outputs a sixth drive signal to the second piezoelectric element are arranged adjacent to each other. Thus, the difference in the wiring length through which the first drive signal supplied to the first piezoelectric element propagates and the wiring length through which the fifth drive signal supplied to the first piezoelectric element propagates can be reduced, and the difference in the wiring length through which the third drive signal supplied to the second piezoelectric element propagates and the wiring length through which the sixth drive signal supplied to the second piezoelectric element propagates can be reduced. Thereby, the ejection accuracy of the liquid ejected from the first ejection unit and the second ejection unit is improved.

[0294] In one aspect of the liquid ejection device, the first ejection amount is larger than the third ejection amount, the second ejection amount is larger than the fourth ejection amount, along the one direction, the first drive circuit and the third drive circuit may be positioned adjacent to each other, and the fifth drive circuit and the sixth drive circuit may be positioned adjacent to each other.

[0295] According to this liquid ejection device, a first drive circuit that outputs a first drive signal for ejecting a large amount of liquid when supplied to a first piezoelectric element and a third drive circuit that outputs a third drive signal for ejecting a large amount of liquid when supplied to a second piezoelectric element are arranged adjacent to each other, and a fifth drive circuit that outputs a fifth drive signal for ejecting a small amount of liquid when supplied to the first piezoelectric element and a sixth drive circuit that outputs a sixth drive signal for ejecting a small amount of liquid when supplied to the second piezoelectric element are arranged adjacent to each other. Thus, on the substrate, the first drive circuit and the third drive circuit that can generate equivalent heat are arranged in the vicinity, and the fifth drive circuit and the sixth drive circuit are arranged in the vicinity. As a result, it becomes possible to perform collective cooling for each possible amount of heat generation, and even when the number of ejection units of the liquid ejection device increases, an optimal heat dissipation structure corresponding to the increased ejection units can be applied.

[0296] In one aspect of the liquid ejection device, The first current amount generated along with the propagation of the first drive signal may be larger than the second current amount generated along with the propagation of the second drive signal, and the third current amount generated along with the propagation of the third drive signal may be larger than the fourth current amount generated along with the propagation of the fourth drive signal.

[0297] In one aspect of the liquid ejection device, The first drive circuit may include a surface-mounted transistor.

[0298] According to this liquid ejection device, even when the first drive circuit includes a surface-mounted transistor, the heat generated in the first drive circuit can be efficiently dissipated.

[0299] In one aspect of the liquid ejection device, The substrate may be provided with a heat sink that dissipates heat of at least any one of the first drive circuit, the second drive circuit, the third drive circuit, and the fourth drive circuit.

[0300] According to this liquid ejection device, by providing a heat sink with excellent heat dissipation characteristics as a heat dissipation member, the heat generated in the first drive circuit, the second drive circuit, the third drive circuit, and the fourth drive circuit can be dissipated more efficiently.

[0301] One aspect of the head drive circuit is a head drive circuit that drives a discharge head having a first discharge unit group including a first discharge unit that includes a first piezoelectric element and discharges liquid in response to driving of the first piezoelectric element, and a second discharge unit group that includes a second discharge unit that includes a second piezoelectric element and discharges liquid in response to driving of the second piezoelectric element, a substrate, a first drive circuit, a second drive circuit, a third drive circuit, and a fourth drive circuit provided side by side along one direction of the substrate, and includes the first drive circuit outputs a first drive signal for driving the first piezoelectric element so that the first discharge unit discharges a liquid of a first discharge amount, the second drive circuit outputs a second drive signal for driving the first piezoelectric element so that the first discharge unit does not discharge liquid, the third drive circuit outputs a third drive signal for driving the second piezoelectric element so that the second discharge unit discharges a liquid of a second discharge amount, the fourth drive circuit outputs a fourth drive signal for driving the second piezoelectric element so that the second discharge unit does not discharge liquid, the third drive circuit is located between the first drive circuit and the second drive circuit along the one direction, the shortest distance between the fourth drive circuit and the second drive circuit is shorter than the shortest distance between the fourth drive circuit and the third drive circuit.

[0302] According to this head driving circuit, the first driving signal drives the first piezoelectric element so that the first ejection unit ejects a liquid with a first ejection amount, and the second driving signal drives the first piezoelectric element so that the first ejection unit does not eject the liquid. Therefore, the voltage amplitude of the first driving signal is larger than the voltage amplitude of the second driving signal. Therefore, the heat generation occurring in the first driving circuit that outputs the first driving signal is larger than the heat generation occurring in the second driving circuit that outputs the second driving signal. Similarly, the third driving signal drives the second piezoelectric element so that the second ejection unit ejects a liquid with a second ejection amount, and the fourth driving signal drives the second piezoelectric element so that the second ejection unit does not eject the liquid. Therefore, the voltage amplitude of the third driving signal is larger than the voltage amplitude of the fourth driving signal. Therefore, the heat generation occurring in the third driving circuit that outputs the third driving signal is larger than the heat generation occurring in the fourth driving circuit that outputs the fourth driving signal. In the head driving circuit, the first driving circuit, the second driving circuit, the third driving circuit, and the fourth driving circuit are provided side by side along one direction of the substrate. The third driving circuit is located between the first driving circuit and the second driving circuit along one direction. The shortest distance between the fourth driving circuit and the second driving circuit is shorter than the shortest distance between the fourth driving circuit and the third driving circuit. That is, the first driving circuit with a large heat generation and the third driving circuit with a large heat generation are arranged in the vicinity on the substrate, and the second driving circuit with a small heat generation and the fourth driving circuit with a small heat generation are arranged in the vicinity on the substrate. In other words, the first driving circuit and the third driving circuit with a large heat generation on the substrate are arranged together, and the second driving circuit and the fourth driving circuit with a small heat generation are arranged together. Thereby, the first driving circuit with a large heat generation and the third driving circuit with a large heat generation can be concentratedly radiated, and whether to provide a heat radiating member for the second driving circuit with a small heat generation and the fourth driving circuit with a small heat generation can be appropriately selected according to the use environment and operating state of the liquid ejection device. As a result, even when a large number of driving circuits including the first driving circuit, the second driving circuit, the third driving circuit, and the fourth driving circuit are provided, an optimal heat radiating structure corresponding to the amount of heat generated in the first driving circuit, the second driving circuit, the third driving circuit, and the fourth driving circuit can be applied, and the heat generated in the first driving circuit, the second driving circuit, the third driving circuit, and the fourth driving circuit can be efficiently radiated.

Explanation of Signs

[0303] 1…Liquid ejection device, 2…Control unit, 3…Liquid container, 4…Conveyor unit, 5…Ejection unit, 10…Head drive module, 20…Liquid ejection module, 23…Ejection module, 30…Wiring member, 31…Housing, 33…Integrated substrate, 34…Flow path structure, 35…Head substrate, 37…Distribution flow path, 39…Fixing plate, 41…Conveyor motor, 42…Conveyor roller, 50-1~50-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…Inverter, 234a, 234b, 234c…Transfer gate, 311…Opening, 313…Integrated substrate insertion part, 315…Holding member, 330…Connection part, 341…Introduction part, 343…Through hole, 351…Opening, 352, 353, 355…Notch, 371…Opening, 373…Introduction part, 388…Wiring member, 391…Opening, 500…Integrated circuit, 510…Modulation circuit, 512, 513…Adder, 514…Comparator, 515…Inverter, 516…Integral attenuator, 517…Attenuator, 520…Gate drive circuit, 521, 522…Gate driver, 550…Amplification circuit, 560…Demodulation circuit, 570, 572…Feedback circuit, 590…Power supply circuit, 600…Ejection part, 610…Diaphragm, 611…Lead electrode, 620…Compliance substrate, 621…Sealing film, 622…Fixed substrate, 623…Nozzle plate, 623a…Liquid injection surface, 630…Communication plate, 641…Protection substrate, 642…Flow path forming substrate, 643…Through hole, 644…Protection space, 660…Case, 661…Introduction path, 662…Connection port, 665…Recess, 710…Heat sink, 711…Bottom part, 712, 713…Side part, 714…Opening, 715~717…Protrusion, 718…Fin part, 720…Group of heat conduction members, 730, 740, 750, 760…Heat 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…Insulation layer, C1~C5…Capacitor, CB…Pressure chamber, CN1,CN2... connection part, D1... diode, FC... wiring member, L1... inductor, Ln1, Ln2... nozzle row, M1, M2... transistor, MN... manifold, N... nozzle, P... medium, R1~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~WA6, WB1~WB6, WC1~WC6... wiring,

Claims

1. A first ejection unit group including a first piezoelectric element and ejecting liquid in response to driving of the first piezoelectric element; A second ejection unit group including a second piezoelectric element and ejecting liquid in response to driving of the second piezoelectric element; A discharge head having the above; A substrate; A first drive circuit, a second drive circuit, a third drive circuit, a fourth drive circuit, a fifth drive circuit, and a sixth drive circuit provided side by side along one direction of the substrate; And; Comprising The first drive circuit outputs a first drive signal for driving the first piezoelectric element so that the first ejection unit ejects a liquid of a first ejection amount; The second drive circuit outputs a second drive signal for driving the first piezoelectric element so that the first ejection unit does not eject liquid; The third drive circuit outputs a third drive signal for driving the second piezoelectric element so that the second ejection unit ejects a liquid of a second ejection amount; The fourth drive circuit outputs a fourth drive signal for driving the second piezoelectric element so that the second ejection unit does not eject liquid; The fifth drive circuit outputs a fifth drive signal for driving the first piezoelectric element so that the first ejection unit ejects a liquid of a third ejection amount; The sixth drive circuit outputs a sixth drive signal for driving the second piezoelectric element so that the second ejection unit ejects a liquid of a fourth ejection amount; The third drive circuit is located between the first drive circuit and the second drive circuit along the one direction; Along the one direction, the fifth drive circuit and the sixth drive circuit are located between the first drive circuit and the second drive circuit and between the first drive circuit and the fourth drive circuit; Along the one direction, the first drive circuit and the third drive circuit are adjacent to each other, and the fifth drive circuit and the sixth drive circuit are adjacent to each other; The shortest distance between the fourth drive circuit and the second drive circuit is shorter than the shortest distance between the fourth drive circuit and the third drive circuit; The first ejection amount is larger than the third ejection amount; The second ejection amount is larger than the fourth ejection amount; A liquid ejection device characterized by the above.

2. A first current amount generated due to propagation of the first drive signal is larger than a second current amount generated due to propagation of the second drive signal, and a third current amount generated due to propagation of the third drive signal is larger than a fourth current amount generated due to propagation of the fourth drive signal. The liquid ejection device according to claim 1, characterized by the above.

3. The first drive circuit includes a surface-mounted transistor. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The liquid ejection device according to any one of claims 1 or 2, characterized in that...

4. A heat sink that is attached to the substrate and dissipates heat from at least any one of the first drive circuit, the second drive circuit, the third drive circuit, and the fourth drive circuit. The liquid ejection device according to any one of claims 1 to 3, characterized in that...

5. A head drive circuit that drives a discharge head having a first discharge unit group including a first piezoelectric element and including a first discharge unit that discharges liquid in response to driving of the first piezoelectric element, and a second discharge unit group including a second discharge unit that includes a second piezoelectric element and discharges liquid in response to driving of the second piezoelectric element, the head drive circuit comprising: 、 a substrate; a first drive circuit, a second drive circuit, a third drive circuit, a fourth drive circuit, a fifth drive circuit, and a sixth drive circuit provided side by side along one direction of the substrate; wherein the first drive circuit outputs a first drive signal for driving the first piezoelectric element so that the first discharge unit discharges a first discharge amount of liquid, the second drive circuit outputs a second drive signal for driving the first piezoelectric element so that the first discharge unit does not discharge liquid, the third drive circuit outputs a third drive signal for driving the second piezoelectric element so that the second discharge unit discharges a second discharge amount of liquid, the fourth drive circuit outputs a fourth drive signal for driving the second piezoelectric element so that the second discharge unit does not discharge liquid, the fifth drive circuit outputs a fifth drive signal for driving the first piezoelectric element so that the first discharge unit discharges a third discharge amount of liquid, the sixth drive circuit outputs a sixth drive signal for driving the second piezoelectric element so that the second discharge unit discharges a fourth discharge amount of liquid, the third drive circuit is located between the first drive circuit and the second drive circuit along the one direction, the fifth drive circuit and the sixth drive circuit are located between the first drive circuit and the second drive circuit and between the first drive circuit and the fourth drive circuit along the one direction, the first drive circuit and the third drive circuit are adjacent to each other along the one direction, the fifth drive circuit and the sixth drive circuit are adjacent to each other, the shortest distance between the fourth drive circuit and the second drive circuit is shorter than the shortest distance between the fourth drive circuit and the third drive circuit, the first discharge amount is larger than the third discharge amount, the second discharge amount is larger than the fourth discharge amount. The head drive circuit is characterized by the above. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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