Liquid ejection device

Abstract

To provide a liquid ejection device which reduces the risk that the liquid ejection device may be enlarged in size, and furthermore enables overshoot occurring in a driving signal.SOLUTION: The liquid ejection device is provided, comprising: an ejection head which ejects liquid; a head drive circuit which outputs a first driving signal for driving a driving element so that liquid is ejected and a second driving signal for driving the driving element so that liquid is not ejected; and a connection member which electrically connects the head drive circuit to the ejection head and which has first wiring through which the first driving signal is transmitted, second wiring through which the second driving signal is transmitted, third wiring through which a reference voltage signal is transmitted and a base material in which the first wiring, the second wiring and the third wiring are provided. The first wiring and the second wiring are provided on a first surface of the base material, and the third wiring is provided on a second surface different from the first surface, and in a first direction along a direction from the first surface toward the second surface, at least either of the first wiring and the second wiring is positioned while overlapping with at least a portion of the third wiring.SELECTED DRAWING: Figure 16

Description

Technical Field

[0001] The present invention relates to a liquid ejection device.

Background Art

[0002] As a liquid ejection device for ejecting liquid, for example, a device using a piezoelectric element such as a piezo element is known. In such a liquid ejection device, when a drive signal is supplied to the piezoelectric element, the piezoelectric element is driven, and an amount of liquid corresponding to the drive of the piezoelectric element is ejected.

[0003] For example, in Patent Document 1, in a large-format printer which is one of the liquid ejection devices that eject liquid by driving a piezoelectric element, by devising the arrangement of the wiring through which the drive signal propagates in a flexible flat cable that propagates the drive signal supplied to the piezoelectric element, a technique for reducing the possibility that an overshoot voltage is superimposed on the drive signal due to mutual induction is disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In response to the market demand for further speeding up the ink ejection speed in recent years, in a liquid ejection device, in addition to shortening the driving waveform period included in the driving signal for driving the piezoelectric element, even for a shortened driving waveform, from the viewpoint of realizing dot formation of a sufficient size, the ejection amount of ink ejected by one driving waveform is increasing. That is, the number of driving waveforms included per unit time in the driving signal is increasing, and the voltage change of the driving waveform is becoming larger. As a result, the peak current generated along with the propagation of the driving signal increases, and the possibility of the overshoot voltage being superimposed on the driving signal due to mutual induction is further increasing. In response to such a problem, when the technique described in Patent Document 1 is applied, the number of wirings included in the cable increases, and it becomes difficult to miniaturize the liquid ejection device. That is, the technique described in Patent Document 1 was not sufficient for the market demand for further speeding up the ink ejection speed of recent liquid ejection devices, and there was room for improvement.

Means for Solving the Problems

[0006] One aspect of the liquid ejection device according to the present invention is an ejection head that ejects liquid in response to driving of a driving element, a head driving circuit that outputs a first driving signal for driving the driving element so that liquid is ejected and a second driving signal for driving the driving element so that liquid is not ejected, a connection member having one end electrically connected to the head driving circuit and the other end electrically connected to the ejection head, and includes the connection member has a first wiring for propagating the first driving signal, a second wiring for propagating the second driving signal, a third wiring for propagating a reference voltage signal serving as a reference potential for driving the driving element, and a base material on which the first wiring, the second wiring, and the third wiring are provided, the first wiring and the second wiring are provided on a first surface of the base material, the third wiring is provided on a second surface different from the first surface of the base material, In a first direction along the direction from the first surface toward the second surface, at least one of the first wiring and the second wiring is positioned overlapping at least a part of the third wiring. is.

Brief Description of the Drawings

[0007]

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MODE FOR CARRYING OUT THE INVENTION

[0008] 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.

[0009] 1. First Embodiment 1.1 Configuration of Liquid Discharge Device FIG. 1 is a diagram showing a schematic configuration of a liquid discharge device 1. As shown in FIG. 1, the liquid discharge device 1 is a so-called line type inkjet printer that forms a desired image on a medium P by discharging ink, which is an example of a liquid, at a desired timing with respect to 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.

[0010] As shown in FIG. 1, the liquid discharge device 1 includes a control unit 2, a liquid container 3, a conveyance unit 4, and a plurality of discharge units 5.

[0011] 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.

[0012] The liquid container 3 stores ink 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 black, cyan, magenta, yellow, red, gray, and the like.

[0013] The conveyance unit 4 includes a conveyance motor 41 and a conveyance roller 42. A conveyance control signal Ctrl-T output from the control unit 2 is input to the conveyance unit 4. Then, based on the input conveyance control signal Ctrl-T, the conveyance motor 41 operates, and as the conveyance roller 42 is rotationally driven with the operation of the conveyance motor 41, the medium P is conveyed along the conveyance direction.

[0014] 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 from 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.

[0015] Further, the liquid ejection modules 20 each provided in the plurality of ejection units 5 are arranged side by side along the main scanning direction so as to be equal to or greater than the width of the medium P, so that ink can be ejected over the entire area in the width direction of the conveyed medium P. Thereby, the liquid ejection device 1 constitutes a line type inkjet printer. Note that the liquid ejection device 1 is not limited to a line type inkjet printer.

[0016] 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 includes a head drive module 10 and a liquid ejection module 20. In the ejection unit 5, the head drive module 10 and the liquid ejection module 20 are electrically connected by one or a plurality of wiring members 30.

[0017] 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 board (FPC: Flexible Printed Circuits).

[0018] The head drive module 10 includes a control circuit 100, drive signal output circuits 50-1 to 50-m, and a conversion circuit 120.

[0019] The control circuit 100 includes a CPU, an FPGA, or the like. 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.

[0020] 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 the 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, part or all of the base data signal dDATA may be output to the liquid ejection module 20 as a single-ended data signal DATA.

[0021] Also, 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.

[0022] Here, each of the drive circuits 52a, 52b, and 52c only needs to be able to generate 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 amplifier circuit, it may include a class-A amplifier circuit, a class-B amplifier circuit, or a class-AB amplifier 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.

[0023] Further, the drive signal output circuit 50-1 has 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, which will be described later, that the liquid discharge module 20 has, and outputs it to the liquid discharge module 20. This reference voltage signal VBS1 may be, for example, a ground potential or a constant potential such as 5.5 V or 6 V. Here, the constant potential includes cases where it can be regarded as a substantially constant potential when variations due to errors such as potential variations caused by the operation of peripheral circuits, potential variations caused by variations in circuit elements, and potential variations caused by the temperature characteristics of circuit elements are taken into account.

[0024] The drive signal output circuits 50-2 to 50-m only differ in the input and output signals and have the same configuration as the drive signal output circuit 50-1. That is, the drive signal output circuit 50-j (j is any one of 1 to m) includes a circuit corresponding to the drive circuits 52a, 52b, and 52c and a circuit corresponding to the reference voltage output circuit 53, and generates drive signals COMAj, COMBj, and COMCj and a reference voltage signal VBSj based on the base drive signals dAj, dBj, and dCj input from the control circuit 100, and outputs them to the liquid discharge module 20.

[0025] Here, in the following description, 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 them, they may simply be referred to as the drive circuit 52. In this case, the drive circuit 52 will be described as generating and outputting the drive signal COM based on the basic drive signal do. On the other hand, when distinguishing between the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50-1 and the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50-j, the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50-1 may be referred to as drive circuits 52a1, 52b1, and 52c1, and the drive circuits 52a, 52b, and 52c included in the drive signal output circuit 50-j may be referred to as drive circuits 52aj, 52bj, and 52cj.

[0026] The liquid ejection module 20 includes a restoration circuit 220 and ejection modules 23-1 to 23-m.

[0027] The restoration circuit 220 restores the data signal DATA into a single-ended signal and separates it into signals 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.

[0028] Specifically, the restoration circuit 220 restores and separates the data signal DATA to generate the clock signal SCK1, the print data signal SI1, and the latch signal LAT1 corresponding to the ejection module 23-1, and outputs them to the ejection module 23-1. Further, the restoration circuit 220 restores and separates the data signal DATA to generate the clock signal SCKj, the print data signal SIj, and the latch signal LATj corresponding to the ejection module 23-j, and outputs them to the ejection module 23-j.

[0029] ​As described above, the restoration circuit 220 restores the data signal DATA of the differential signal output by the head drive module 10 and separates the restored signal into 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 the respective 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 the respective 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.

[0030] Here, in view of the fact that the restoration circuit 220 generates the clock signals SCK1 to SCKm, the print data signals SI1 to SIm, and the latch signals LAT1 to LATm by restoring and separating the data signal DATA, 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 is the basis of the data signal DATA includes signals corresponding to the respective clock signals SCK1 to SCKm, print data signals SI1 to SIm, and latch signals LAT1 to LATm. That is, the base data signal dDATA includes signals for controlling the operations of the ejection modules 23-1 to 23-m included in the liquid ejection module 20.

[0031] The ejection module 23-1 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.

[0032] The ejection module 23-1 receives 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. The drive signals COMA1, COMB1, COMC1, the clock signal SCK1, the print data signal SI1, and the latch signal LAT1 are input to a drive signal selection circuit 200 included in the ejection module 23-1. Based on the input clock signal SCK1, print data signal SI1, and latch signal LAT1, the drive signal selection circuit 200 generates a drive signal VOUT by selecting or not selecting each of the drive signals COMA1, COMB1, COMC1, and supplies it to one end of a piezoelectric element 60 included in the corresponding ejection 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, so that ink is ejected from the corresponding ejection unit 600.

[0033] 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.

[0034] The ejection module 23-j receives the drive signals COMAj, COMBj, COMCj, the reference voltage signal VBSj, the clock signal SCKj, the print data signal SIj, and the latch signal L ATj and [a certain signal] are input. 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, a 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, and ink is ejected from the corresponding ejection unit 600.

[0035] The liquid ejection device 1 of the first embodiment configured as described above 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 by the control unit 2, and controls the ejection of ink from the liquid ejection module 20 included in the ejection unit 5. Thereby, the liquid ejection device 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.

[0036] Here, the ejection modules 23-1 to 23-m included in the liquid ejection module 20 have the same configuration except that the input signals are different. 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.

[0037] That is, the ejection module 23 receives the drive signals COMA, COMB, COMC, the reference voltage signal VBS, the clock signal SCK, the print data signal SI, and the latch signal LAT. The drive signals COMA, COMB, COMC, the clock signal SCK, the print data signal SI, and the latch signal LAT are input to a drive signal selection circuit 200 included in the ejection module 23. Based on the input clock signal SCK, print data signal SI, and latch signal LAT, the drive signal selection circuit 200 generates a drive signal VOUT by selecting or not selecting each of the drive signals COMA, COMB, COMC, 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 VBS 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, so that ink is ejected from the corresponding ejection unit 600.

[0038] As described above, the liquid ejection device 1 in the present embodiment includes a liquid ejection module 20 including an ejection module 23 that ejects ink in response to driving of the piezoelectric element 60, a head drive module 10 including drive signal output circuits 50-1 to 50-m that output drive signals COMA, COMB, COMC, and a wiring member 30 having one end electrically connected to the head drive module 10 and the other end electrically connected to the liquid ejection module 20. Here, the piezoelectric element 60 is an example of a drive element, the ejection module 23 that ejects ink in response to driving of the piezoelectric element 60 or the liquid ejection module 20 including the ejection module 23 is an example of an ejection head, and any one of the drive signal output circuits 50-1 to 50-m that output the drive signals COMA, COMB, COMC, or the head drive module 10 including the drive signal output circuits 50-1 to 50-m is an example of a head drive circuit.

[0039] 1.2 Functional Configuration of Drive Signal Selection Circuit Next, the configuration and operation of the drive signal selection circuit 200 included in the ejection module 23 will be described. In describing the configuration and operation of the drive signal selection circuit 200 included in 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. The drive signal COMB includes a trapezoidal waveform Bdp arranged in the period T. This trapezoidal waveform Bdp is a signal waveform having 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. The drive signal COMC includes a trapezoidal waveform Cdp arranged in the period T. This trapezoidal waveform Cdp is a signal waveform having a smaller voltage amplitude than the trapezoidal waveforms Adp and Bdp, and when supplied to one end of the piezoelectric element 60, vibrates the ink near the nozzle orifice portion so that no ink is ejected from the ejection unit 600 corresponding to the piezoelectric element 60. This trapezoidal waveform Cdp, when supplied to the piezoelectric element 60, vibrates the ink near the nozzle orifice portion of the ejection unit 600 including the piezoelectric element 60. Thereby, the possibility of an increase in the viscosity of the ink near the nozzle orifice portion is reduced.

[0041] That is, the drive signal COMA is a signal for driving the piezoelectric element 60 so that ink is ejected, the drive signal COMB is a signal for driving the piezoelectric element 60 so that ink is ejected, and the drive signal COMC is a signal for driving the piezoelectric element 60 so that ink is not ejected. When such a drive signal COMA is supplied to the piezoelectric element 60, the amount of ink ejected from the liquid ejection module 20 including the ejection module 23 is different from the amount of ink ejected from the liquid ejection module 20 including the ejection module 23 when the drive signal COMB is supplied to the piezoelectric element 60.

[0042] 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. That is, the trapezoidal waveforms Adp, Bdp, and Cdp are signal waveforms that each start at the voltage Vc and end at the voltage Vc.

[0043] 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 part 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 part 600 corresponding to the piezoelectric element 60 may be referred to as a small 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 part 600 corresponding to the piezoelectric element 60 may be referred to as fine vibration.

[0044] Note that, in FIG. 3, each of the drive signals COMA, COMB, and COMC is illustrated as including one trapezoidal waveform in a period T. However, each of the drive signals COMA, COMB, and COMC may include two or more consecutive trapezoidal waveforms in the period T. In this case, a signal that defines the switching timing of two or more trapezoidal waveforms is input to the drive signal selection circuit 200, and the ejection unit 600 ejects ink a plurality of times in the period T. Then, dots are formed on the medium P by the ink ejected in a plurality of times in the period T landing and bonding on the medium P. As a result, the number of gradations of the dots formed on the medium P can be increased. can

[0045] On the other hand, in the liquid ejection device 1 shown in the first embodiment, the description will be made assuming that the drive signals COMA, COMB, and COMC are signals each including one trapezoidal waveform in the period T. As a result, the period T for forming dots on the medium P can be shortened, the image formation speed on the medium P can be increased, and by supplying the drive signals COMA, COMB, and COMC in parallel to the liquid ejection module 20, an increase in the number of gradations of the dots formed on the medium P is also realized. Here, the period T from when the latch signal LAT rises until the latch signal LAT rises next may be referred to as a dot formation period for forming dots of a desired size on the medium P.

[0046] 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 shown in FIG. 2 may include signal waveforms different from each other. Similarly, each of the drive signals COMB1 to COMBm and the drive signals COMC1 to COMCm may also include signal waveforms different from each other.

[0047] Next, the configuration and operation of a drive signal selection circuit 200 that outputs a 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.

[0048] A print data signal SI, a latch signal LAT, and a clock signal SCK are input to the selection control circuit 210. The selection control circuit 210 also has a set of a shift register (S / R) 212, a latch circuit 214, and a decoder 216 corresponding to each of the n ejection units 600. That is, the drive signal selection circuit 200 includes the same n shift registers 212, latch circuits 214, and decoders 216 as the total number of ejection units 600.

[0049] 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 "micro-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].

[0050] Specifically, the n shift registers 212 corresponding to the ejection units 600 are connected in series with each other. The serially input print data signal SI is sequentially transferred to the subsequent stage of the shift registers 212 connected in series according to the clock signal SCK. Then, by stopping the supply of the clock signal SCK, the n shift registers 212 hold the 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 series, 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.

[0051] 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.

[0052] 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, in the first embodiment, when the 2-bit print data [SIH, SIL] latched by the corresponding latch circuit 214 is [1, 0], the logic levels of the selection signals S1, S2, S3 are set to L, H, L levels at period T.

[0053] 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. Then, 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.

[0054] 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.

[0055] 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 does not conduct 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.

[0056] 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 does not conduct 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.

[0057] 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, the 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 outputs the drive signal COMC to the output terminal not.

[0058] 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.

[0059] 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.

[0060] 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 shown as LT1, LT2, …, LTn.

[0061] The decoder 216 outputs selection signals S1, S2, S3 of logic levels according to the dot size defined by the latched 2-bit print data [SIH, SIL].

[0062] Specifically, when the print data [SIH, SIL] is [1, 1], the decoder 216 outputs the logic 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 the "large dot LD". Also, when the print data [SIH, SIL] is [1, 0], the decoder 216 outputs the logic 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 the "small dot SD". Also, when the print data [SIH, SIL] is [0, 1], the decoder 216 outputs the logic 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 the constant "non-ejection ND" at the voltage Vc. Also, when the print data [SIH, SIL] is [0, 0], the decoder 216 outputs the logic 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 the "fine vibration BSD".

[0063] Here, when the selection circuit 230 does not select any of the trapezoidal waveforms Adp, Bdp, and Cdp, the voltage Vc that was immediately supplied to the corresponding piezoelectric element 60 is held by the capacitance component of the piezoelectric element 60 at one end 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 the voltage Vc held by the capacitance component of the piezoelectric element 60 is supplied to the piezoelectric element 60 as the drive signal VOUT when none of the trapezoidal waveforms Adp, Bdp, and Cdp are selected as the drive signal VOUT.

[0064] As described above, based on the print data signal SI, the latch signal LAT, and the clock signal SCK, the drive signal selection circuit 200 selects or deselects the drive signals COMA, COMB, and COMC, generates drive signals VOUT corresponding to each of the plurality of ejection units 600, and outputs them to the corresponding ejection units 600. Thereby, the amount of ink ejected from each of the plurality of ejection units 600 is individually controlled.

[0065] 1.3 Configuration of the Liquid Ejection Module Next, the structure of the liquid ejection module 20 will be described with reference to FIGS. 8 to 10. FIG. 8 is a diagram showing the structure of the liquid ejection module 20. Here, when explaining the structure of the liquid ejection module 20, FIGS. 8 to 10 illustrate arrows indicating the X1 direction, Y1 direction, and Z1 direction that are perpendicular to each other. Also, in the description of FIGS. 8 to 10, 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 may be referred to as the -Z1 side and the tip side as the +Z1 side. Further, in the following description, the liquid ejection module 20 included in the liquid ejection device 1 in the first embodiment will be described as having six ejection modules 23, and when distinguishing each of the six ejection modules 23, they may be referred to as ejection modules 23-1 to 23-6.

[0066] The liquid ejection module 20 includes a housing 31, a collective 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 stacked 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 located 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 collective 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 such that a part thereof is exposed to the outside of the liquid ejection module 20 between the distribution flow path 37 and the fixing plate 39.

[0067] 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. 9 is a diagram showing an example of the structure of the ejection module 23. FIG. 10 is a diagram showing an example of a cross section of the ejection module 23. Here, FIG. 10 is a cross-sectional view of the ejection module 23 shown in FIG. 9 cut along the line A-a shown in FIG. 9, and the line A-a 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.

[0068] As shown in FIGS. 9 and 10, the ejection 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 ejection module 23 is n, which is the same as the number of ejection portions 600 included in the ejection module 23. In the first embodiment, it will be described assuming that the number of the nozzles N1 and the number of the nozzles N2 included in the ejection module 23 are the same. That is, it will be described assuming that the ejection module 23 has n / 2 nozzles N1 and n / 2 nozzles N2. Here, when there is no need to distinguish between the nozzles N1 and N2 in the following description, they may simply be referred to as nozzles N.

[0069] The ejection module 23 includes 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.

[0070] 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, it may be simply referred to as the pressure chamber CB. In the following description, when it is not necessary to distinguish between the pressure chamber CB1 and the pressure chamber CB2, it may be simply referred to as the pressure chamber CB.

[0071] 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.

[0072] On the -Z1 side of the flow path forming substrate 642 and on the +Z1 side of the nozzle plate 623, the communication plate 630 is located. 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.

[0073] The manifold MN1 includes a supply communication passage RA1 and a connection communication passage RX1. The supply communication passage RA1 is provided by penetrating the communication plate 630 along the Z1 direction, and the connection communication passage RX1 opens to the nozzle plate 623 side of the communication plate 630 without penetrating the communication plate 630 in the Z1 direction and is provided up to the middle in the Z1 direction. Similarly, the manifold MN2 includes a supply communication passage RA2 and a connection communication passage RX2. The supply communication passage RA2 is provided by penetrating the communication plate 630 along the Z1 direction, and the connection communication passage RX2 opens to the nozzle plate 623 side of the communication plate 630 without penetrating the communication plate 630 in the Z1 direction and is provided up to the middle in the Z1 direction. And the connection communication passage RX1 included in the manifold MN1 communicates with the corresponding pressure chamber CB1 through the pressure chamber communication passage RK1, and the connection communication passage RX2 included in the manifold MN2 communicates with the corresponding pressure chamber CB2 through the pressure chamber communication passage RK2.

[0074] Here, in the following description, when it is not necessary to distinguish between the nozzle communication passage RR1 and the nozzle communication passage RR2, it may simply be referred to as the nozzle communication passage RR. When it is not necessary to distinguish between the manifold MN1 and the manifold MN2, it may simply be referred to as the manifold MN. When it is not necessary to distinguish between the supply communication passage RA1 and the supply communication passage RA2, it may simply be referred to as the supply communication passage RA. When it is not necessary to distinguish between the connection communication passage RX1 and the connection communication passage RX2, it may simply be referred to as the connection communication passage RX.

[0075] The diaphragm 610 is located on the +Z1 side surface of the flow path forming substrate 642. 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. And 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.

[0076] A protective substrate 641 is bonded to the surface of the flow path forming substrate 642 on the +Z1 side. The protective substrate 641 forms a protective space 644 for protecting the piezoelectric element 60. The protective substrate 641 is also provided with a through hole 643 penetrating along the Z1 direction. An end of a lead electrode 611 drawn from the electrode of the piezoelectric element 60 is extended so as to be exposed inside the through hole 643. A wiring member 388 is electrically connected to the end of the lead electrode 611 exposed inside the through hole 643.

[0077] In addition, the protective substrate 641 and the communication plate 630 are provided with manifolds that communicate with the multiple pressure chambers CB. A case 660 that defines a part of the nozzle MN is fixed. The case 660 is joined to the protective substrate 641 and also joined to the communication plate 630. Specifically, the case 660 has a recess 665 on the -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 larger than the surface where the protective substrate 641 is joined to the flow path forming substrate 642. Then, in a state in which the flow path forming substrate 642 and the like are accommodated in the recess 665, the opening surface on the -Z1 side of the recess 665 is sealed by the communication plate 630. As a result, the supply communication channel RB1 and the supply communication channel RB2 are defined on the outer periphery of the flow path forming substrate 642 by the case 660, the flow path forming substrate 642, and the protective substrate 641. Here, when it is not necessary to distinguish between the supply communication channel RB1 and the supply communication channel RB2, they may be simply referred to as the supply communication channel RB.

[0078] A compliance substrate 620 is provided on the surface of the communicating plate 630 where the supply communicating passage RA and the connection communicating passage RX open. The openings of the supply communicating passage RA and the connection communicating passage RX are sealed by this compliance substrate 620. Such a compliance substrate 620 has a sealing film 621 and a fixed substrate 622. The sealing film 621 is formed of a flexible thin film or the like, and the fixed substrate 622 is formed of a hard material such as a metal, for example, stainless steel.

[0079] 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 that communicates with the through hole 643 of the protective substrate 641 and penetrates along the Z1 direction, and through which the wiring member 388 is inserted.

[0080] 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 COF (Chip On Film) mounted on the wiring member 388. At least a part of the drive signal selection circuit 200 described above is mounted on this integrated circuit 201.

[0081] In the ejection module 23 configured as described above, the drive signal VOUT output by the drive signal selection circuit 200 and the reference voltage signal VBS are supplied to the piezoelectric element 60 via the wiring member 388. 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 this 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 ejection unit 600 described above.

[0082] 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 that penetrate the fixing plate 39 along the Z2 direction. The liquid ejection surface 623a of the ejection module 23 is exposed from each of these six openings 391. That is, six ejection modules 23 are fixed to the fixing plate 39 so that the liquid ejection surface 623a is exposed from each of the openings 391 corresponding thereto.

[0083] The distribution flow path 37 is located on the +Z1 side of the discharge module 23. On the +Z1 side surface of the distribution flow path 37, four introduction parts 373 are provided. The four introduction parts 373 are flow path pipes that protrude 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) that communicate with the four introduction parts 373 are located. The flow path pipes (not shown) located on the -Z1 side surface of this distribution flow path 37 communicate with the introduction paths 661 each of the six discharge modules 23 has. Further, the distribution flow path 37 penetrates along the Z1 direction and has six openings 371. Wiring members 388 each of the six discharge modules 23 has are inserted into the six openings 371.

[0084] The head substrate 35 is located on the +Z1 side of the distribution flow path 37. A wiring member FC that is electrically connected to the collective substrate 33 described later is attached to the head substrate 35. Also, four openings 351 and cutouts 352 and 353 are formed in the head substrate 35. Wiring members 388 that the discharge modules 23-2 to 23-5 have are inserted into the four openings 351. And each wiring member 388 of the discharge modules 23-2 to 23-5 that has passed through the four openings 351 is electrically connected to the head substrate 35 by solder or the like. Also, the wiring member 388 that the discharge module 23-1 has passes through the cutout 352, and the wiring member 388 that the discharge module 23-6 has passes through the cutout 353. And each wiring member 388 of the discharge modules 23-1 and 23-6 that has passed through each of the cutouts 352 and 353 is electrically connected to the head substrate 35 by solder or the like.

[0085] Also, four cutouts 355 are formed at the four corners of the head substrate 35. The four introduction parts 373 pass through the four cutouts 355. And the four introduction parts 373 that have passed through the cutouts 355 are connected to the flow path structure 34 located on the +Z1 side of the head substrate 35.

[0086] 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 in a state where the flow path plate Su1 is located on the +Z1 side and the flow path plate Su2 is located on the -Z1 side, and are joined to each other by an adhesive or the like.

[0087] The flow path structure 34 has four introduction parts 341 that protrude toward the +Z1 side along the Z1 direction on the surface on the +Z1 side. The four introduction parts 341 communicate with a flow path hole (not shown) formed on the surface on the -Z1 side of the flow path structure 34 through an ink flow path formed inside the flow path structure 34. Then, a flow path hole (not shown) formed on the surface on the -Z1 side of the flow path structure 34 and the four introduction parts 373 communicate with each other. Further, 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. In addition to the ink flow path that communicates the introduction part 341 and the flow path hole (not shown) formed on the surface on the -Z1 side inside the flow path structure 34, a filter or the like for catching foreign matter contained in the ink flowing through the ink flow path may be provided.

[0088] 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 part 313, and a holding member 315.

[0089] Each of the four openings 311 has inserted therein the four introduction parts 341 that the flow path structure 34 has. Then, ink is supplied from the liquid container 3 to the four introduction parts 341 that have passed through the four openings 311 via a tube or the like (not shown).

[0090] 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 the data signal DATA, drive signals COMA, COMB, COMC, reference voltage signal VBS, and other power supply voltages output by the head drive module 10 are input to the connection portion 330 via the wiring member 30. Further, a wiring member FC of 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. 8, 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 the data signal DATA, drive signals COMA, COMB, COMC, reference voltage signal VBS, and other power supply voltages output by the head drive module 10 are input to the assembly substrate 33 via 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.

[0091] 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 through the ink flow path formed inside the flow path structure 34, and then supplied to the four introduction portions 373 of the distribution flow path 37. The ink supplied to the distribution flow path 37 through the four introduction portions 373 is distributed corresponding to each of the six ejection modules 23 in the ink flow path (not shown) formed inside the distribution flow path 37, and then supplied to the introduction path 661 of the corresponding ejection module 23. Then, the ink supplied to the ejection module 23 through the introduction path 661 is stored in the pressure chamber CB included in the ejection portion 600.

[0092] 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 ejection units 600 are generated by the integrated circuit 201 including the drive signal selection circuit 200 provided in the wiring member 388, and are 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.

[0093] 1.4 Structure of Head Drive Module Next, the structure of the head drive module 10 will be described with reference to FIGS. 11 to 12. Here, FIGS. 11 to 12 illustrate arrows indicating directions X2, Y2, and Z2 that are independent of the aforementioned X1 direction, Y1 direction, and Z1 direction and are perpendicular to each other. In the description of FIGS. 11 to 12, the starting side of the arrow indicating the X2 direction is referred to as the -X2 side, the tip side is referred to as the +X2 side, the starting side of the arrow indicating the Y2 direction is referred to as the -Y2 side, the tip side is 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 as the +Z2 side.

[0094] FIG. 11 is a diagram showing an example of the structure of the head drive module 10. As shown in FIG. 11, the head drive module 10 includes a drive circuit board 800 including a plurality of drive circuits 52, a heat sink 710, a group of heat conduction members 720, a plurality of screws 780, and a cooling fan 770. In the head drive module 10, the drive circuit board 800 and the heat sink 710 are provided in the order of the drive circuit board 800 and the heat sink 710 along the Z2 direction, the group of heat conduction members 720 is located between the drive circuit board 800 and the heat sink 710, and the heat sink 710 is attached to the drive circuit board 800 by a plurality of screws 780. Thereby, the group of heat conduction members 720 is sandwiched between the drive circuit board 800 and the heat sink 710, and the heat generated in the drive circuit board 800 is conducted to the heat sink 710 through the group of heat conduction members 720. As a result, the heat generated in the drive circuit board 800 is released to the outside of the head drive module 10.

[0095] An example of the structure of the drive circuit board 800 will be described. FIG. 12 is a diagram showing an example of the structure of the drive circuit board 800. As shown in FIG. 12, the drive circuit board 800 includes a wiring board 810, drive circuits 52a1 to 52a6, 52b1 to 52b6, 52c1 to 52c6 as a plurality of drive circuits 52, connection portions CN1 and CN2, and an integrated circuit 101.

[0096] The wiring board 810 has a substantially shape including sides 811 and 812 facing each other along the X2 direction, and sides 813 and 814 facing each other along the Y2 direction. Specifically, side 811 is located on the -X2 side of the wiring board 810, side 812 is located on the +X2 side of the wiring board 810, side 813 intersects sides 811 and 812 and is located on the +Y2 side of the wiring board 810, and side 814 intersects sides 811 and 812 and is located on the -Y2 side of the wiring board 810. Also, a plurality of through holes 820 are formed in the wiring board 810. Some of the plurality of through holes 820 are arranged side by side along side 813 of the wiring board 810, and some different ones of the plurality of through holes 820 are arranged side by side along side 814 of the wiring board 810. That is, a plurality of through holes 820 are formed in two rows along the X2 direction in the wiring board 810.

[0097] The connection part CN1 is located along side 811 of the wiring board 810. A cable (not shown) electrically connected to the control unit 2 is attached to this 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. Here, the head drive module 10 and the control unit 2 may be connected by, for example, a USB (Universal Serial Bus) cable or an HDMI (High-Definition Multimedia Interface: registered trademark) cable. In this case, as the connection part CN1, a USB connector or an HDMI (registered trademark) connector corresponding to the type of the connected cable is used. Also, the head drive module 10 and the control unit 2 may be directly electrically connected without passing through a cable. As the connection part CN1 in this case, for example, a BtoB (Board to Board) connector can be used.

[0098] The connection part CN2 is located along the side 812 of the wiring board 810. One end of the wiring member 30 is attached to this 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. That is, 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 to the liquid ejection module 20 via the connection part CN2 and the wiring member 30. Details of the wiring member 30 that electrically connects the head drive module 10 and the liquid ejection module 20 will be described later.

[0099] 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 and outputs various signals based on the image information signal IP input via the connection part CN1. Also, the integrated circuit 101 may include part or all of the conversion circuit 120 in addition to the control circuit 100. In the present embodiment, the integrated circuit 101 will be described as including all of the control circuit 100 and all of the conversion circuit 120, but it is not limited to this.

[0100] A plurality of drive circuits 52 are arranged side by side along the X2 direction between the integrated circuit 101 and the connection part CN2.

[0101] Specifically, the drive circuits 52a1 to 52a6, 52b1 to 52b6, 52c1 to 52c6 as a plurality of drive circuits 52 face from the side 811 to the side 812 between the integrated circuit 101 and the connection part CN2, and the drive circuits 52c6, 52b6, 52a6, 52c5, 52b5, 52a5, 52c4, 52b4, 52a4, 52c3, 52b3, 52a3, 52c2, 52b2, 52a2, 52c1, 52b1, 52a1 are arranged in this order.

[0102] In the driving circuit board 800 configured as described above, the image information signal IP input via the connection part CN1 is supplied to the integrated circuit 101. Then, the integrated circuit 101 generates and outputs the basic driving signals dA1~dA6, dB1~dB6, dC1~dC6, and the data signal DATA based on the image information signal IP by the control circuit 100 and the conversion circuit 120 included in the integrated circuit 101. The basic driving signals dA1~dA6, dB1~dB6, dC1~dC6 propagate through a wiring pattern (not shown) of the wiring board 810 and are input to the corresponding driving circuits 52. The driving circuit 52 generates and outputs the corresponding driving signals COMA1~COMA6, COMB1~COMB6, COMC1~COMC6 based on the input basic driving signals dA1~dA6, dB1~dB6, dC1~dC6. The driving signals COMA1~COMA6, COMB1~COMB6, COMC1~COMC6 output by the plurality of driving circuits 52 propagate through a wiring pattern (not shown) of the wiring board 810, the connection part CN2, and the wiring member 30, and are supplied to the liquid ejection module 20.

[0103] Here, FIG. 12 illustrates the case where the integrated circuit 101 is mounted on the wiring board 810 together with the plurality of driving circuits 52. However, the integrated circuit 101 may be mounted on a substrate (not shown) different from the driving circuits 52. As shown in FIG. 12, when the integrated circuit 101 is mounted on the same substrate as the plurality of driving circuits 52, the wiring length for signal propagation between the plurality of driving circuits 52 and the integrated circuit 101 can be shortened. As a result, the possibility of noise or the like being superimposed on the signals propagating between the plurality of driving circuits 52 and the integrated circuit 101 is reduced. On the other hand, the plurality of driving circuits 52 generate more heat than the integrated circuit 101. Therefore, the heat generated by the plurality of driving circuits 52 may reduce the operating stability of the integrated circuit 101. To address such a problem, by mounting the integrated circuit 101 on a substrate different from the plurality of driving circuits 52, the possibility of the heat generated by the plurality of driving circuits 52 contributing to the integrated circuit 101 can be reduced, and the possibility of the operating stability of the integrated circuit 101 being reduced can be reduced.

[0104] Returning to FIG. 11, in the head drive module 10, the heat sink 710 is located on the +Z2 side of the drive circuit board 800. Then, the heat sink 710 releases heat by conducting the heat generated in the drive circuit board 800. Thereby, the possibility of the temperature of the drive circuit board 800 rising is reduced, and the operating stability of various circuits included in the drive circuit board 800 is improved. Such a heat sink 710 is a metal substance with high thermal conductivity from the viewpoint of efficiently releasing the heat generated in the drive circuit board 800, and is composed of, for example, aluminum, iron, copper, etc.

[0105] The plurality of screws 780 fix the heat sink 710 to the drive circuit board 800. Specifically, each of the plurality of screws 780 is inserted through the plurality of through holes 820 formed in the wiring board 810 from the -Z2 side toward the +Z2 side, and is tightened to the heat sink 710 located on the +Z2 side of the drive circuit board 800, thereby attaching the heat sink 710 to the drive circuit board 800.

[0106] Here, the plurality of screws 780 only need to be able to fix the heat sink 710 to the drive circuit board 800, and for example, rivets may be used. Also, the head drive module 10 does not include the plurality of screws 780, and a part of the heat sink 710 is inserted through the through hole 820, and a part of the heat sink 710 that has passed through the through hole 820 may be attached to the metal part of the drive circuit board 800 by solder or the like.

[0107] The heat conduction member group 720 has a plurality of heat conduction members 730. The heat conduction member group 720 is located between the drive circuit board 800 and the heat sink 710 in the Z2 direction and is sandwiched between the drive circuit board 800 and the heat sink 710. Then, the heat conduction member group 720 conducts the heat generated in the drive circuit board 800 to the heat sink 710.

[0108] Such a plurality of heat conduction members 730 are provided corresponding to electronic components in the drive circuit 52 that generate particularly large amounts of heat. Specifically, when the drive circuit 52 is configured to include, for example, a class-D amplifier circuit, some of the plurality of heat conduction members 730 are provided corresponding to a semiconductor device that outputs a gate drive signal for driving a transistor pair based on the base drive signals dA1~dA6, dB1~dB6, dC1~dC6. Also, some different ones of the plurality of heat conduction members 730 are provided corresponding to a transistor pair that outputs an amplified signal based on the base drive signals dA1~dA6, dB1~dB6, dC1~dC6 by operating based on the gate drive signal. Further, some still different ones of the plurality of heat conduction members 730 are provided corresponding to an inductor element that generates and outputs the drive signals COMA1~COMA6, COMB1~COMB6, COMC1~COMC6 by smoothing the amplified signal output by the transistor pair.

[0109] Such a plurality of heat conduction members 730 are substances having flame retardancy and electrical insulation in addition to elasticity, and for example, can include silicone or acrylic resin, and gel sheets or rubber sheets having heat conductivity can be used.

[0110] In the head drive module 10 configured as described above, due to various tolerances including the mounting error of the heat sink 710 to the wiring board 810, the error caused by the mounting variation of various electronic components included in the drive circuit 52, and the dimensional error of the heat sink 710 and various electronic components included in the drive circuit 52, even when the heat sink 710 is attached to the wiring board 810, there is variation in the contact state between the heat sink 710 and the drive circuit board 800. As a result, the conduction efficiency of the heat generated in the drive circuit board 800 to the heat sink 710 decreases, and there is a possibility that the heat sink 710 may not be able to sufficiently release the heat.

[0111] Also, in view of the fact that the heat sink 710 is fastened to the drive circuit board 800 by a plurality of screws 780, when the plurality of screws 780 when attached to the drive circuit board 800 are tightened, or due to the various tolerances described above, unintended stress is applied to various electronic components mounted on the drive circuit board 800, and as a result, there is also a risk of causing malfunction in the head drive module 10.

[0112] Regarding such a problem, since the heat conduction member group 720 has elasticity, the variation in the contact state between the heat sink 710 and various electronic components is reduced, and the risk of applying unintended stress to various electronic components mounted on the wiring board 810 is also reduced. As a result, the operating stability of the head drive module 10 is improved.

[0113] Furthermore, as described above, the heat sink 710 is a substance with high thermal conductivity, and metals such as aluminum and iron are used. Therefore, when the heat sink 710 and various electronic components mounted on the wiring board 810 are in electrical contact, there is also a risk of causing malfunction in the drive circuit board 800. Regarding such a problem, since the heat conduction member group 720 has flame retardancy and electrical insulation properties, the risk of the heat sink 710 and various electronic components mounted on the wiring board 810 being in electrical contact is reduced, and as a result, the operating stability of the head drive module 10 is improved.

[0114] The cooling fan 770 is located on the -Z2 side of the heat sink 710. And the heat sink 710 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.

[0115] Specifically, the opening 714 is a through-hole that penetrates the heat sink 710 along the Z2 direction. When the heat sink 710 is attached to the drive circuit board 800, it functions as an opening that communicates with the inside of the head drive module 10. The cooling fan 770 is attached so as to cover the opening 714. When the cooling fan 770 operates, outside air is introduced into the inside of the head drive module 10 through the opening 714. As a result, the circulation efficiency of the air floating inside the head drive module 10 is improved, and as a result, the heat dissipation efficiency of the heat generated by the drive circuit board 800 by the heat sink 710 is further improved.

[0116] Here, the cooling fan 770 may be attached so as to enhance the circulation efficiency of the air floating inside the head drive module 10, and may be located on any side surface of the +X2 side, -X2 side, +Y2 side, or -Y2 side of the head drive module 10. Further, the head drive module 10 may have a plurality of cooling fans 770. Further, the operation that the cooling fan 770 introduces outside air into the inside of the head drive module 10 does not necessarily mean that the cooling fan 770 operates so that outside air is taken into the inside of the head drive module 10 through the cooling fan 770, and also includes the operation that the cooling fan 770 discharges the air floating inside the head drive module 10 through the cooling fan 770.

[0117] 1.5 Structure of Wiring Member Next, the structure of the wiring member 30 that electrically connects the head drive module 10 and the liquid ejection module 20 will be described with reference to FIGS. 13 to 16. In the following description, among the wiring members 30 that electrically connect the head drive module 10 and the liquid ejection module 20, the structure of the wiring member 30 that propagates the high-voltage drive signals COMA1 to COMA6, COMB1 to COMB6, COMC1 to COMC6 and the reference voltage signals VBS1 to VBS6 corresponding to each of the drive signals COMA1 to COMA6, COMB1 to COMB6, COMC1 to COMC6 will be described.

[0118] FIG. 13 is a diagram showing an example of the structure of the wiring member 30. As shown in FIG. 13, the wiring member 30 includes a base material 700 and wiring groups WG1 to WG6 provided on the base material 700.

[0119] The base material 700 is configured to include a flexible substance such as a plastic film, polyimide, or PET in order to realize the flexibility of the wiring member 30. Such a base material 700 has a substantially rectangular shape including sides 701 and 702 facing each other and sides 703 and 704 facing each other, and includes a surface 705 and a surface 706 different from the surface 705. In the liquid ejection device 1 of the first embodiment, the wiring member 30 is described as having a substantially rectangular shape, but the shape of the wiring member 30 is not limited to a rectangular shape.

[0120] Specifically, the side 701 and the side 702 are located facing each other, and the side 703 and the side 704 are located facing each other. And the side 701 intersects the side 703 and the side 704, and the side 702 intersects the side 703 and the side 704. In this case, one of the planes within the plane formed by the sides 701, 702, 703, and 704 is the surface 705, and the other plane within the plane formed by the sides 701, 702, 703, and 704 is the surface 706.

[0121] Also, FIG. 13 shows an X3 direction, a Y3 direction, and a Z3 direction that intersect each other. The X3 direction, the Y3 direction, and the Z3 direction are directions independent of the X1 direction, the Y1 direction, the Z1 direction, the X2 direction, the Y2 direction, and the Z2 direction described above. Specifically, the X3 direction is a direction along the direction from the side 701 to the side 702 along the base material 700, the Y3 direction is a direction along the direction from the side 703 to the side 704 along the base material 700, and the Z3 direction is a direction along the direction from the surface 705 to the surface 706 along the base material 700.

[0122] Here, as described above, the wiring member 30 is a flexible member such as an FPC, and by bending or flexing, the head drive module 10 and the liquid ejection module 20 are electrically Connect. Therefore, when the wiring member 30 is curved or bent, the direction from side 701 to side 702 of the base material 700 along the wiring member 30 and the direction from side 703 to side 704 of the base material 700 along the wiring member 30 are also curved and bent. That is, in FIG. 13, although each of the X3 direction, Y3 direction, and Z3 direction is shown as a straight line direction, the X3 direction, Y3 direction, and Z3 direction are not limited to the straight line direction, and may be the curved or bent direction along with the curvature and bending of the wiring member 30. In the following description, the starting point side of the arrow indicating the X3 direction may be referred to as the -X3 side, the tip side may be referred to as the +X3 side, the starting point side of the arrow indicating the Y3 direction may be referred to as the -Y3 side, the tip side may be referred to as the +Y3 side, and the starting point side of the arrow indicating the Z3 direction may be referred to as the -Z3 side, and the tip side may be referred to as the +Z3 side.

[0123] The wiring groups WG1 to WG6 are provided corresponding to the ejection modules 23-1 to 23-6 respectively, and include a plurality of wirings for propagating signals supplied to the ejection modules 23-1 to 23-6 respectively. Specifically, the wiring group WG1 includes wirings for propagating the drive signals COMA1, COMB1, and COMC1 corresponding to the ejection module 23-1 respectively, and a wiring for propagating the reference voltage signal VBS1. Also, the wiring group WG2 is located on the +Y3 side of the wiring group WG1, and includes wirings for propagating the drive signals COMA2, COMB2, and COMC2 corresponding to the ejection module 23-2 respectively, and a wiring for propagating the reference voltage signal VBS2. Also, the wiring group WG3 is located on the +Y3 side of the wiring group WG2, and includes wirings for propagating the drive signals COMA3, COMB3, and COMC3 corresponding to the ejection module 23-3 respectively, and a wiring for propagating the reference voltage signal VBS3. Also, the wiring group WG4 is located on the +Y3 side of the wiring group WG3, and includes wirings for propagating the drive signals COMA4, COMB4, and COMC4 corresponding to the ejection module 23-4 respectively, and a wiring for propagating the reference voltage signal VBS4. Also, the wiring group WG5 is located on the +Y3 side of the wiring group WG4, and includes wirings for propagating the drive signals COMA5, COMB5, and COMC5 corresponding to the ejection module 23-5 respectively, and a wiring for propagating the reference voltage signal VBS5. Also, the wiring group WG6 is located on the +Y3 side of the wiring group WG5, and includes wirings for propagating the drive signals COMA6, COMB6, and COMC6 corresponding to the ejection module 23-6 respectively, and a wiring for propagating the reference voltage signal VBS6.

[0124] That is, the wiring groups WG1 to WG6 are arranged in order of the wiring group WG1, the wiring group WG2, the wiring group WG3, the wiring group WG4, the wiring group WG5, and the wiring group WG6 from the -Y3 side to the +Y3 side in the direction from the side 703 to the side 704 of the base material 700, which is the direction along the Y3 direction.

[0125] The wiring member 30 configured as described above has one end, the end on the side of the side 701 of the base material 700, attached to the connection portion CN2 of the head drive module 10, and the other end, the end on the side of the side 702 of the base material 700, attached to the connection portion 330 of the liquid ejection module 20. Thereby, the head drive module 10 and the liquid ejection module 20 are electrically connected via the wiring member 30.

[0126] Next, an example of the configuration of the wiring groups WG1 to WG6 will be described. The wiring groups WG1 to WG6 provided on the base material 700 included in the wiring member 30 in the liquid ejection device 1 of the first embodiment have the same configuration except that the signals to be propagated are different. Therefore, in the following description, only the configuration of the wiring group WG1 corresponding to the ejection module 23-1 will be described, and the description of the respective configurations of the wiring groups WG2 to WG6 corresponding to the ejection modules 23-2 to 23-6 will be omitted.

[0127] FIG. 14 is a diagram showing an example of the wiring provided on the surface 705 of the base material 700 among the wiring group WG1, and FIG. 15 is a diagram showing an example of the wiring provided on the surface 706 of the base material 700 among the wiring group WG1. Note that FIGS. 14 and 15 illustrate the X3 direction, the Y3 direction, and the Z3 direction indicating the same direction as in FIG. 13. Here, FIGS. 14 and 15 are both views of the wiring member 30 viewed from the + Z3 side toward the -Z3 side. That is, FIG. 14 is a plan view showing an example of the configuration of the surface 705 of the base material 700 among the wiring group WG1, and FIG. 15 is a perspective view showing an example of the configuration of the surface 706 of the base material 700 among the wiring group WG1. In FIG. 15, a part of the configuration provided on the surface 705 is illustrated by a broken line.

[0128] As shown in FIGS. 14 and 15, the wiring group WG1 includes terminals TIA, TIB, TIC, TIS, terminals TOA, TOB, TOC, TOS, wiring patterns PA1, PB1, PC1, PS1, PS2, PS3, and through holes SH1, SH2.

[0129] The terminals TIA, TIB, TIC, and TIS are located side by side in the order of TIA, TIB, TIS, and TIC along the side 701 on the surface 705 of the base material 700. Then, when the wiring member 30 is attached to the connection portion CN2, each of the terminals TIA, TIB, TIC, and TIS comes into contact with an electrode (not shown) of the connection portion CN2. Thereby, the wiring member 30 and the connection portion CN2 are electrically connected. Here, FIGS. 14 and 15 illustrate the case where the wiring member 30 has three terminals TIA, three terminals TIB, three terminals TIS, and one terminal TIC. However, the number of the terminals TIA, TIB, TIS, and TIC of the wiring member 30 is not limited to this, and may be appropriately changed according to the amount of current generated during signal propagation and the like.

[0130] The terminals TOA, TOB, TOC, and TOS are located side by side in the order of TOA, TOB, TOS, and TOC along the side 702 on the surface 705 of the base material 700. Then, when the wiring member 30 is attached to the connection portion 330, each of the terminals TOA, TOB, TOC, and TOS comes into contact with an electrode (not shown) of the connection portion 330. Thereby, the wiring member 30 and the connection portion 330 are electrically connected. Here, FIGS. 14 and 15 illustrate the case where the wiring member 30 has three terminals TOA, three terminals TOB, three terminals TOS, and one terminal TOC. However, the number of the terminals TOA, TOB, TOS, and TOC of the wiring member 30 is not limited to this, and may be appropriately changed according to the amount of current generated during signal propagation and the like.

[0131] The wiring pattern PA1 is provided on the surface 705 and electrically connects three terminals TIA and three terminals TOA. Thereby, the signal input to the three terminals TIA from the head drive module 10 via the connection portion CN2 propagates through the wiring pattern PA1 and is supplied to the connection portion 330 of the liquid ejection module 20 via the three terminals TOA.

[0132] On plane 705, wiring pattern PB1 is provided on the +Y3 side of wiring pattern PA1 and electrically connects three terminals TIB and three terminals TOB. As a result, the signal input to the three terminals TIB from the head drive module 10 via the connection part CN2 propagates through the wiring pattern PB1 and is supplied to the connection part 330 of the liquid ejection module 20 via the three terminals TOB.

[0133] On plane 705, wiring pattern PC1 is provided on the +Y3 side of wiring pattern PB1 and electrically connects one terminal TIC and one terminal TOC. As a result, the signal input to the one terminal TIC from the head drive module 10 via the connection part CN2 propagates through the wiring pattern PC1 and is supplied to the connection part 330 of the liquid ejection module 20 via the one terminal TOC.

[0134] On plane 705, wiring pattern PS1 is located between wiring pattern PB1 and wiring pattern PC1 and electrically connects three terminals TIS and through hole SH1. Through hole SH1 penetrates the base material 700 along the Z3 direction and electrically connects the wiring pattern PS1 provided on plane 705 and the wiring pattern PS3 provided on plane 706. Wiring pat tern PS3 electrically connects through hole SH1 and through hole SH2 on plane 706. Through hole SH2 penetrates the base material 700 along the Z3 direction and electrically connects the wiring pattern PS3 provided on plane 706 and the wiring pattern PS2 provided on plane 705. Wiring pattern PS2 is located between wiring pattern PB1 and wiring pattern PC1 on plane 705 and electrically connects three terminals TOS and through hole SH2. As a result, the signal input to the three terminals TIS from the head drive module 10 via the connection part CN2 propagates through the wiring pattern PS1, through hole SH1, wiring pattern PS3, through hole SH2, and wiring pattern PS2 and is supplied to the connection part 330 of the liquid ejection module 20 via the three terminals TOS.

[0135] In the liquid ejection device 1 of the present embodiment, the drive signal COMA1 output from the head drive module 10 is input to the terminal TIA, propagated through the wiring pattern PA1, supplied to the liquid ejection module 20 via the terminal TOA, the drive signal COMB1 is input to the terminal TIB, propagated through the wiring pattern PB1, and supplied to the liquid ejection module 20 via the terminal TOB. Further, the drive signal COMC1, which has a smaller current amount generated when propagated than the drive signals COMA1 and COMB1, is input to the terminal TIC, propagated through the wiring pattern PC1, and supplied to the liquid ejection module 20 via the terminal TOC. Then, the reference voltage signal VBS1 is input to the terminal TIS, propagated through the wiring patterns PS1, PS3, PS2, and supplied to the liquid ejection module 20 via the terminal TOS.

[0136] That is, the wiring member 30 has a wiring pattern PA1 that propagates the drive signal COMA1, a wiring pattern PB1 that propagates the drive signal COMB1, a wiring pattern PC1 that propagates the drive signal COMC1, wiring patterns PS1, PS2, PS3 that propagate the reference voltage signal VBS1 that serves as the reference potential for driving the piezoelectric element 60, and a base material 700 on which the wiring patterns PA1, PB1, PC1, PS1, PS2, PS3 are provided. The wiring patterns PA1, PB1, PC1, PS1, PS2 are provided on the surface 705 of the base material 700, and the wiring pattern PS3 is provided on a surface 706 different from the surface 705 of the base material 700.

[0137] In the wiring member 30 configured as described above, when viewed from the Z3 direction, which is the direction from the surface 705 to the surface 706 of the base material 700, at least one of the wiring pattern PA1 and the wiring pattern PC1 provided on the surface 705 is positioned overlapping at least a part of the wiring pattern PS3 provided on the surface 706.

[0138] A specific example of the configuration of the wiring member 30 will be described with reference to FIG. 16. FIG. 16 is a cross-sectional view when the wiring member 30 is cut along the line B-b shown in FIGS. 14 and 15. As shown in FIG. 16, the wiring member 30 includes the above-described base material 700, a wiring pattern PA1 provided on the surface 705 of the base material 700 for propagating the drive signal COMA1, a wiring pattern PB1 for propagating the drive signal COMB1, a wiring pattern PC1 for propagating the drive signal COMC1, and in addition to a wiring pattern PS3 provided on the surface 706 of the base material 700 for propagating the reference voltage signal VBS1, has an insulating layer IL.

[0139] The insulating layer IL is a flexible insulator such as a polyimide film, for example, which insulates the wiring patterns PA1, PB1, PC1, and PS3 from each other and also insulates the wiring patterns PA1, PB1, PC1, and PS3 from the outside of the wiring member 30.

[0140] As shown in FIG. 16, in the cross-section when the wiring member 30 is cut along the line B-b, the wiring pattern PA1 is a conductor having a length along the Y3 direction of width wa and a length along the Z3 direction of thickness ta, and is located on the surface 705 of the base material 700. Also, in the cross-section when the wiring member 30 is cut along the line B-b, the wiring pattern PB1 is a conductor having a length along the Y3 direction of width wb and a length along the Z3 direction of thickness ta, and is located on the surface 705 of the base material 700 on the +Y3 side of the wiring pattern PA1. Also, in the cross-section when the wiring member 30 is cut along the line B-b, the wiring pattern PC1 is a conductor having a length along the Y3 direction of width wc and a length along the Z3 direction of thickness ta, and is located on the surface 705 of the base material 700 on the +Y3 side of the wiring pattern PB1. In the cross-section when the wiring member 30 is cut along the line B-b, the wiring pattern PB1 is a conductor having a length along the Y3 direction of width wb and a length along the Z3 direction of thickness ta, and is located on the surface 705 of the base material 700 on the +Y3 side of the wiring pattern PA1. Also, in the cross-section when the wiring member 30 is cut along the line B-b, the wiring pattern PC1 is a conductor having a length along the Y3 direction of width wc and a length along the Z3 direction of thickness ta, and is located on the surface 705 of the base material 700 on the +Y3 side of the wiring pattern PB1.

[0141] In this case, the width wa of the wiring pattern PA1 is larger than the width wc of the wiring pattern PC1, and the width wb of the wiring pattern PB1 is larger than the width wc of the wiring pattern PC1. That is, in the cross section when the wiring member 30 is cut along the B-b line, the effective cross-sectional area of the wiring pattern PA1 through which the drive signal COMA1 propagates is larger than the effective cross-sectional area of the wiring pattern PC1 through which the drive signal COMC1 propagates, and the effective cross-sectional area of the wiring pattern PB1 through which the drive signal COMB1 propagates is larger than the effective cross-sectional area of the wiring pattern PC1 through which the drive signal COMC1 propagates.

[0142] As described above, the drive signals COMA1 and COMB1 are signals for driving the piezoelectric element 60 so as to eject ink, while the drive signal COMC1 is a signal for driving the piezoelectric element 60 so as not to eject ink. Therefore, the amount of current generated when the drive signals COMA1 and COMB1 propagate through the wiring member 30 is larger than the amount of current generated when the drive signal COMC1 propagates through the wiring member 30. By making the effective cross-sectional area of the wiring pattern PA1 through which the drive signal COMA1 propagates larger than the effective cross-sectional area of the wiring pattern PC1 through which the drive signal COMC1 propagates, and making the effective cross-sectional area of the wiring pattern PB1 through which the drive signal COMB1 propagates larger than the effective cross-sectional area of the wiring pattern PC1 through which the drive signal COMC1 propagates, it becomes possible to reduce the influence of the impedance of the wiring member 30 when the drive signals COMA1, COMB1, and COMC1 propagate through the wiring member 30. As a result, the possibility of distortion occurring in the waveforms of the drive signals COMA1, COMB1, and COMC1 is reduced, and the temperature rise of the wiring member 30 caused by the current generated during the propagation of the drive signals COMA1, COMB1, and COMC1 can be reduced, improving the reliability of the liquid ejection device 1.

[0143] Here, in FIG. 16, it is exemplified that the lengths of the wiring patterns PA1, PB1, and PC1 along the Z3 direction are all common and equal to the thickness ta. This is because when forming the wiring patterns PA1, PB1, and PC1 on the surface 705 of the base material 700, the copper foil serving as the base of the wiring patterns PA1, PB1, and PC1 is adhered to the surface 705 of the base material 700, and the copper foil is processed into a predetermined pattern by an etching process, from which the wiring patterns PA1, PB1, and PC1 are formed. However, the manufacturing method of the wiring member 30 is not limited to the method described above. Therefore, the lengths of the wiring patterns PA1, PB1, and PC1 along the Z3 direction may be individually different lengths.

[0144] Also, in the cross-section when the wiring member 30 is cut along the B-b line, the wiring pattern PS3 is a conductor having a length along the Y3 direction of width ws and a length along the Z3 direction of thickness ts, and is located on the surface 706 of the base material 700. At this time, as shown in FIG. 16, at least a part of the -Y3 side end of the wiring pattern PS3 overlaps and is located with the -Y3 side end of the wiring pattern PA1 in the direction along the Z3 direction, and at least a part of the +Y3 side end of the wiring pattern PS3 overlaps and is located with the -Y3 side end of the wiring pattern PC1. That is, the width ws, which is the length of the wiring pattern PS3 along the Y3 direction, is larger than the width wa, which is the length of the wiring pattern PA1 along the Y3 direction, larger than the width wb, which is the length of the wiring pattern PB1 along the Y3 direction, and larger than the width wc, which is the length of the wiring pattern PC1 along the Y3 direction. Thereby, at least a part of the wiring pattern PS3 can overlap and be located with the wiring patterns PA1, PB1, and PC1 in the direction along the Z3 direction.

[0145] As described above, at one end of the piezoelectric element 60 included in the liquid ejection module 20, a drive signal CO A drive signal VOUT generated based on MA1, COMB1, and COMC1 is supplied, and a reference voltage signal VBS1 is supplied to the other end of the piezoelectric element 60. That is, in the wiring pattern PS3, a current amount equivalent to the sum of the currents flowing through the wiring patterns PA1, PB1, and PC1 flows in a direction opposite to the currents flowing through the wiring patterns PA1, PB1, and PC1. In this case, as shown in FIG. 16, at least a part of the wiring pattern PS3 overlaps with the wiring patterns PA1, PB1, and PC1 in the Z3 direction, so that the magnetic field generated by the current flowing through the wiring patterns PA1, PB1, and PC1 and the magnetic field generated by the current flowing through the wiring pattern PS3 cancel each other out. As a result, the inductance component caused by the current generated when the wiring member 30 propagates the drive signals COMA1, COMB1, and COMC1 is reduced.

[0146] Then, by reducing the inductance component caused by the current generated when the wiring member 30 propagates the drive signals COMA1, COMB1, and COMC1, the possibility of waveform distortion occurring in the drive signals COMA1, COMB1, and COMC1 is reduced, the waveform accuracy of the drive signals COMA1, COMB1, and COMC1 is improved, and the waveform accuracy of the drive signal VOUT generated based on the drive signals COMA1, COMB1, and COMC1 is improved. As a result, the ink ejection accuracy is improved.

[0147] Here, as shown in FIG. 16, it is preferable that at least a part of the wiring pattern PS3 overlaps with all of the wiring patterns PA1, PB1, and PC1 in the direction along the Z3 direction, but it is not limited to this. As long as at least a part of the wiring pattern PS3 overlaps with at least a part of any one of the wiring patterns PA1, PB1, and PC1, the inductance component generated when the drive signals COMA1, COMB1, and COMC1 are propagated can be reduced.

[0148] Also, from the perspective of reducing the inductance component caused by the current generated when the drive signals COMA1, COMB1, and COMC1 propagate through the wiring member 30, as shown in FIG. 16, it is preferable to make the width wa of the wiring pattern PA1 larger than the thickness ta, make the width wb of the wiring pattern PB1 larger than the thickness ta, make the width wc of the wiring pattern PC1 larger than the thickness ta, and make the width ws of the wiring pattern PS3 larger than the thickness ts. As a result, it becomes possible to increase the area where the wiring patterns PA1, PB1, PC1 and the wiring pattern PS3 face each other via the base material 700. Consequently, the cancellation efficiency between the magnetic field generated by the current flowing through each of the wiring patterns PA1, PB1, PC1 and the magnetic field generated by the current flowing through the wiring pattern PS3 is improved, and the inductance component caused by the current generated when the wiring member 30 propagates the drive signals COMA1, COMB1, and COMC1 can be further reduced. As a result, the possibility of waveform distortion occurring in the drive signals COMA1, COMB1, and COMC1 is further reduced.

[0149] Here, the wiring member 30 is an example of a connection member. Also, one of the drive signals COMA1 and COMB1 for driving the piezoelectric element 60 so that ink is ejected is an example of a first drive signal, the other of the drive signals COMA1 and COMB1 for driving the piezoelectric element 60 so that ink is ejected is an example of a third drive signal, and the drive signal COMC1 for driving the piezoelectric element 60 so that ink is not ejected is an example of a second drive signal. The wiring pattern PA1 or the wiring pattern PB1 through which one of the drive signals COMA1 and COMB1 corresponding to the first drive signal propagates is an example of a first wiring, the wiring pattern PA1 or the wiring pattern PB1 through which the other of the drive signals COMA1 and COMB1 corresponding to the third drive signal propagates is an example of a fourth wiring, the wiring pattern PC1 through which the drive signal COMC1 corresponding to the second drive signal propagates is an example of a second wiring, and the wiring pattern PS3 through which the reference voltage signal VBS1 propagates is an example of a third wiring. Also, the surface 705 of the base material 700 is an example of a first surface, and the surface 706 is an example of a second surface. And the Z3 direction along the direction from the surface 705 to the surface 706 is an example of a first direction. The X3 direction along the wiring member 30 from the side 701 which is one end toward the side 702 which is the other end is an example of the second direction, and it is the direction in which the wiring patterns PA1, PB1, and PC1 are arranged. The Y3 direction which intersects both the Z3 direction and the X3 direction is an example of the third direction.

[0150] 1.6 Operational effects In the liquid ejection device 1, when a flexible flat cable (FFC) as shown in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2019-005961) is used when propagating the drive signal COMA1 for driving the piezoelectric element 60 so as to eject ink from the head drive module 10 to the liquid ejection module 20, the drive signal COMC1 for driving the piezoelectric element 60 so as not to eject ink, and the reference voltage signal VBS1 which is the reference potential for driving the piezoelectric element 60, from the viewpoint of further increasing the ejection speed of the ink in the liquid ejection device 1, when the current amount generated along with the drive signal COMA1 for driving the piezoelectric element 60 so as to eject ink increases, it becomes necessary to increase the number of wirings for propagating the drive signal COMA. Along with the increase in the number of wirings for propagating the drive signal COMA, from the viewpoint of reducing the inductance component, the number of wirings for propagating the reference voltage signal VBS also increases. As a result, the area occupied by the wiring member 30 in the liquid ejection device 1 increases, and the liquid ejection device 1 becomes larger.

[0151] In response to such problems, in the liquid ejection device 1 according to the present embodiment, a wiring pattern PA1 that propagates a drive signal COMA1 for driving the piezoelectric element 60 so as to eject ink, a wiring pattern PC1 that propagates a drive signal COMC1 for driving the piezoelectric element 60 so as not to eject ink, and wiring patterns PS1, PS2, and PS3 that propagate a reference voltage signal VBS1 that serves as a reference potential for driving the piezoelectric element 60 are provided on a single wiring member 30. The wiring patterns PA1 and PC1 are provided on the surface 705 of the base material 700 included in the wiring member 30, and the wiring pattern PC3 is provided on the surface 706 of the base material 700 included in the wiring member 30. That is, in the liquid ejection device 1 of the present embodiment, the wiring member 30 is a wiring board in which the wiring patterns PA1, PC1 and the wiring pattern PC3 are provided on the base material 700, and is composed of, for example, an FPC or the like. As a result, it is possible to arbitrarily change the cross-sectional area of the wiring through which each of the drive signal COMA1 for driving the piezoelectric element 60 so as to eject ink, the drive signal COMC1 for driving the piezoelectric element 60 so as not to eject ink, and the reference voltage signal VBS1 that serves as the reference potential for driving the piezoelectric element 60 propagates. Thereby, even when the amount of current generated along with the drive signal COMA1 for driving the piezoelectric element 60 so as to eject ink increases, it becomes possible to form wiring with an optimal current density on the wiring member 30. That is, it is possible to reduce the possibility that the number of wirings included in the wiring member 30 increases as the amount of current generated when propagating the drive signal COMA increases. As a result, it is possible to reduce the possibility that the area occupied by the wiring member 30 in the liquid ejection device 1 increases, and it is possible to reduce the possibility that the liquid ejection device 1 becomes larger in size.

[0152] Further, by arranging at least a part of the wiring patterns PA1 and PC1 provided on the surface 705 of the base material 700 of the wiring member 30 to overlap with the wiring pattern PC3 and the wiring pattern PS3 provided on the surface 706 of the base material 700 of the wiring member 30 in the normal direction of the base material 700 and in the direction from the surface 705 to the surface 706, it is possible to reduce the inductance component caused by the current generated when the drive signal COMA1 propagates. As a result, the possibility that the overshoot voltage caused by the inductance component is superimposed on the drive signal COMA is reduced. That is, the waveform accuracy of the drive signal COMA1 supplied to the liquid ejection module 20 is improved, and as a result, the ink ejection accuracy in the liquid ejection module 20 is also improved.

[0153] Furthermore, since the wiring patterns PA1 and PC1 are provided on the surface 705 of the base material 700 of the wiring member 30 and the wiring pattern PC3 is provided on the surface 706 of the same base material 700, even when the wiring member 30 is bent and deformed, the relative positional relationship between the wiring patterns PA1 and PC1 and the wiring pattern PC3 can be kept substantially constant. As a result, even when the wiring member 30 is bent and deformed, it is possible to keep the cancellation relationship between the magnetic field generated by the current flowing through the wiring patterns PA1 and PC1 and the magnetic field generated by the current flowing through the wiring pattern PC3 constant. Even when the wiring member 30 is bent and deformed, the possibility that the reduction efficiency of the inductance component caused by the current generated when the drive signal COMA1 propagates decreases is reduced. That is, even when the wiring member 30 is bent and deformed, the possibility that the waveform accuracy of the drive signal COMA1 supplied to the liquid ejection module 20 decreases is reduced, and the ink ejection accuracy in the liquid ejection module 20 is improved.

[0154] 1.7 Modification Example In the liquid ejection device 1 according to the present embodiment described above, although the wiring groups WG1 to WG6 included in the wiring member 30 have been described as having the same configuration except that the signals they propagate are different, each of the wiring groups WG1 to WG6 included in the wiring member 30 includes a wiring pattern PA1 that propagates the drive signal COMA, a wiring pattern PB1 that propagates the drive signal COMB, a wiring pattern PC1 that propagates the drive signal COMC, and a wiring pattern PS3 that propagates a reference voltage signal VBS1 that serves as a reference potential for driving the piezoelectric element 60, and a base material 700 on which the wiring patterns PA1, PB1, PC1, PS1, PS2, and PS3 are provided. In each of the wiring groups WG1 to WG6 included in the wiring member 30, the wiring pattern PA1 that propagates the drive signal COMA, the wiring pattern PB1 that propagates the drive signal COMB, and the wiring pattern PC1 that propagates the drive signal COMC may be provided on one surface of the base material 700, and the wiring pattern PS3 may be provided on the other surface of the base material 700. In this case, when each of the wiring groups WG1 to WG6 included in the wiring member 30 is viewed from the Z3 direction, it is sufficient that at least one of the wiring pattern PA1 and the wiring pattern PC1 overlaps at least a part of the wiring pattern PS3.

[0155] An example of the configuration of the wiring member 30 in the modified example will be described with reference to FIG. 17. FIG. 17 is a cross-sectional view of the wiring member 30 in the modified example. As shown in FIG. 17, a wiring pattern PA1 that propagates the drive signal COMA1, a wiring pattern PB1 that propagates the drive signal COMB1, and a wiring pattern PC1 that propagates the drive signal COMC1 in the wiring group WG1 are provided on the surface 705 of the base material 700, and the wiring pattern PS3 is provided on a surface 706 different from the surface 705 of the base material 700. On the other hand, a wiring pattern PA1 that propagates the drive signal COMA2, a wiring pattern PB1 that propagates the drive signal COMB2, and a wiring pattern PC1 that propagates the drive signal COMC2 in the wiring group WG2 are provided on the surface 706 of the base material 700, and the wiring pattern PS3 is provided on a surface 705 different from the surface 706 of the base material 700. Even with the wiring member 30 having such a configuration, the same operational effects can be achieved.

[0156] 2. Second embodiment Next, a liquid ejection device 1 according to a second embodiment will be described. In describing the liquid ejection device 1 according to the second embodiment, the same components as those in the liquid ejection device 1 according to the first embodiment will be denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0157] The second embodiment of the liquid ejection device 1 differs from the first embodiment of the liquid ejection device 1 in that, in the wiring member 30, the wiring through which the drive signal COMA1 propagates and the wiring through which the drive signal COMB1 propagates are provided on different surfaces of the substrate 700, the wiring through which the drive signal COMA1 propagates and the wiring through which the reference voltage signal VBS propagates are positioned opposite each other along the Z3 direction, and the wiring through which the drive signal COMB1 propagates and the wiring through which the reference voltage signal VBS propagates are positioned opposite each other along the Z3 direction.

[0158] FIG. 18 is a diagram showing an example of wiring provided on a surface 705 of a base material 700 in a wiring group WG1 of a wiring member 30 in the second embodiment, and FIG. 19 is a diagram showing an example of wiring provided on a surface 705 of a base material 700 in the second embodiment. 18 is a diagram showing an example of wiring provided on a surface 706 of a substrate 700 in a wiring group WG1 of a line member 30. Note that, in FIG. 18 and FIG. 19, the same X3 direction, Y3 direction, and Z3 direction as in the first embodiment are shown. Here, FIG. 18 and FIG. 19 are both views of the wiring member 30 viewed from the +Z3 side toward the -Z3 side. That is, FIG. 18 is a plan view showing an example of the configuration of a surface 705 of a substrate 700 in a wiring group WG1, and FIG. 19 is a perspective view showing an example of the configuration of a surface 706 of a substrate 700 in a wiring group WG1. Also, in FIG. 19, a part of the configuration provided on the surface 705 is illustrated by a dashed line.

[0159] As shown in Figures 18 and 19, wiring group WG1 includes terminals TIA, TIB, TIC, and TIS, terminals TOA, TOB, TOC, and TOS, wiring patterns PA2, PB2, PB3, PB4, PC2, PC3, PC4, PS4, and PS5, and through holes SH3, SH4, SH5, SH6, SH7, and SH8.

[0160] The terminals TIA, TIB, TIC, and TIS are arranged in the order of TIA, TIB, TIS, and TIC along the side 701 on the surface 705 of the base material 700, similar to the first embodiment. Then, by attaching the wiring member 30 to the connection portion CN2, each of the terminals TIA, TIB, TIC, and TIS comes into contact with an electrode (not shown) of the connection portion CN2. Thereby, the wiring member 30 and the connection portion CN2 are electrically connected. Further, the terminals TOA, TOB, TOC, and TOS are arranged in the order of TOA, TOB, TOS, and TOC along the side 702 on the surface 705 of the base material 700, similar to the first embodiment. Then, by attaching the wiring member 30 to the connection portion 330, each of the terminals TOA, TOB, TOC, and TOS comes into contact with an electrode (not shown) of the connection portion 330. Thereby, the wiring member 30 and the connection portion 330 are electrically connected.

[0161] The wiring pattern PA2 is provided on the surface 705 and electrically connects three terminals TIA and three terminals TOA. Thereby, the signal input to the three terminals TIA from the head drive module 10 via the connection portion CN2 propagates through the wiring pattern PA2 and is supplied to the connection portion 330 of the liquid ejection module 20 via the three terminals TOA.

[0162] The wiring pattern PB2 is located on the +Y3 side of the wiring pattern PA2 on the surface 705 and electrically connects the three terminals TIB and the through hole SH3. The through hole SH3 penetrates the base material 700 along the Z3 direction and electrically connects the wiring pattern PB2 provided on the surface 705 and the wiring pattern PB4 provided on the surface 706. The wiring pattern PB4 electrically connects the through hole SH3 and the through hole SH4 on the surface 706. The through hole SH4 penetrates the base material 700 along the Z3 direction and electrically connects the wiring pattern PB4 provided on the surface 706 and the wiring pattern PB3 provided on the surface 705. The wiring pattern PB3 is located on the +Y3 side of the wiring pattern PA2 on the surface 705 and electrically connects the three terminals TOB and the through hole SH4. Thereby, the signal input to the three terminals TIB from the head drive module 10 via the connection portion CN2 propagates through the wiring pattern PB2, the through hole SH3, the wiring pattern PB4, the through hole SH4, and the wiring pattern PB3, and is supplied to the connection portion 330 of the liquid ejection module 20 via the three terminals TOB.

[0163] The wiring pattern PC2 is located on the +Y3 side of the wiring pattern PB2 on the surface 705 and electrically connects one terminal TIC and the through hole SH5. The through hole SH5 penetrates the base material 700 along the Z3 direction and electrically connects the wiring pattern PC2 provided on the surface 705 and the wiring pattern PC4 provided on the surface 706. The wiring pattern PC4 electrically connects the through hole SH5 and the through hole SH6 on the surface 706. The through hole SH6 penetrates the base material 700 along the Z3 direction and electrically connects the wiring pattern PC4 provided on the surface 706 and the wiring pattern PC3 provided on the surface 705. The wiring pat The turn PC3 is located on the +Y3 side of the wiring pattern PB2 on the surface 705 and electrically connects one terminal TOC and the through hole SH6. Thereby, the signals input to the three terminals TIC from the head drive module 10 via the connection part CN2 are propagated through the wiring pattern PC2, the through hole SH5, the wiring pattern PC4, the through hole SH6, and the wiring pattern PC3, and supplied to the connection part 330 of the liquid ejection module 20 via one terminal TOC.

[0164] The wiring pattern PS4 is on the +Y3 side of the wiring pattern PA2 on the surface 705, with a part located between the wiring pattern PB2 and the wiring pattern PC2 and a different part located between the wiring pattern PB3 and the wiring pattern PC3. And the wiring pattern PS4 electrically connects three terminals TIS and three terminals TOS. Also, the wiring pattern PS4 is electrically connected to the through holes SH7 and SH8. The through hole SH7 penetrates the base material 700 along the Z3 direction and electrically connects the wiring pattern PS4 provided on the surface 705 and the wiring pattern PS5 provided on the surface 706. The through hole SH8 is located on the +X3 side of the through hole SH7 and penetrates the base material 700 along the Z3 direction. Thereby, the through hole SH8 electrically connects the wiring pattern PS4 provided on the surface 705 and the wiring pattern PS5 provided on the surface 706. Thereby, the signals input to the three terminals TIS from the head drive module 10 via the connection part CN2 are propagated through the wiring pattern PS4 and supplied to the connection part 330 of the liquid ejection module 20 via the three terminals TOS, and are propagated through the wiring pattern PS5 provided in parallel with the wiring pattern PS4 by the through holes SH7 and SH8 and supplied to the connection part 330 of the liquid ejection module 20 via the three terminals TOS.

[0165] Also in the wiring member 30 of the second embodiment configured like the above-described place, similar to the liquid ejection apparatus 1 of the first embodiment, the drive signal COMA1 output from the head drive module 10 is input to the terminal TIA, the drive signal COMB1 is input to the terminal TIB, the drive signal COMC1 is input to the terminal TIC, and the reference voltage signal VBS1 is input to the terminal TIS.

[0166] The drive signal COMA1 input to the terminal TIA propagates through the wiring pattern PA2 and is supplied to the liquid ejection module 20 via the terminal TOA. The drive signal COMB1 input to the terminal TIB propagates through the wiring patterns PB2, PB3, PB4 and is supplied to the liquid ejection module 20 via the terminal TOB. The drive signal COMC1 input to the terminal TIC propagates through the wiring patterns PC2, PC3, PC4 and is supplied to the liquid ejection module 20 via the terminal TOC. The reference voltage signal VBS1 input to the terminal TIS branches at the through hole SH7 in the wiring pattern PS4. One of the branched reference voltage signals VBS1 propagates through the wiring pattern PS4 and is supplied to the liquid ejection module 20 via the terminal TOS, and the other branched reference voltage signal VBS1 propagates through the wiring pattern PS5 via the through hole SH7 and merges into the wiring pattern PS4 via the through hole SH8. That is, the reference voltage signal VBS1 input to the terminal TIS propagates through the wiring pattern PS4 and the wiring pattern PS5 provided in parallel with the wiring pattern PS4, and is supplied to the liquid ejection module 20 via the terminal TOS.

[0167] That is, the wiring member 30 in the second embodiment includes a wiring pattern PA2 that propagates the drive signal COMA1, wiring patterns PB2 to PB4 that propagate the drive signal COMB1, wiring patterns PC2 to PC4 that propagate the drive signal COMC1, wiring patterns PS4 and PS5 that propagate the reference voltage signal VBS1 which is the reference potential for driving the piezoelectric element 60, and a base material 700 on which the wiring patterns PA2, PB2 to PB4, PC2 to PC4, PS4, and PS5 are provided. And the wiring patterns PA2, PB2, PB3, PC2, PC3, and PS4 are provided on the surface 705 of the base material 700, and the wiring patterns PB4 and PS5 are provided on a surface 706 different from the surface 705 of the base material 700.

[0168] In the wiring member 30 configured as described above, when the base material 700 is viewed from the Z3 direction, at least a part of the wiring pattern PA2 provided on the surface 705 is located overlapping with the wiring pattern PS5 provided on the surface 706, and at least a part of the wiring pattern PB4 provided on the surface 706 is located overlapping with the wiring pattern PS4 provided on the surface 705.

[0169] A specific example of the configuration of such a wiring member 30 will be described with reference to FIG. 20. FIG. 20 is a cross-sectional view when the wiring member 30 is cut along the C-c line shown in FIGS. 18 and 19. As shown in FIG. 20, at least a part of the wiring pattern PA2 provided on the surface 705 of the base material 700 that propagates the drive signal COMA1 is located overlapping in the direction along the Z3 direction with the wiring pattern PS5 provided on the surface 706 of the base material 700 that propagates the reference voltage signal VBS1. Also, at least a part of at least one of the wiring pattern PB4 that propagates the drive signal COMB1 and the wiring pattern PC4 that propagates the drive signal COMC1 provided on the surface 706 of the base material 700 is located overlapping along the Z3 direction with the wiring pattern PS5 provided on the surface 706 of the base material 700 that propagates the reference voltage signal VBS1.

[0170] Even in the liquid ejection device 1 of the second embodiment configured as described above, the same operational effects as those of the liquid ejection device 1 of the first embodiment can be achieved.

[0171] Here, a drive signal COMB1 for driving the piezoelectric element 60 so that ink is ejected is an example of a first drive signal in the second embodiment, a drive signal COMA1 for driving the piezoelectric element 60 so that ink is ejected is an example of a third drive signal in the second embodiment, and a drive signal COMC1 for driving the piezoelectric element 60 so that ink is not ejected is an example of a second drive signal in the second embodiment. And a wiring pattern PB4 through which the drive signal COMB1 corresponding to the first drive signal propagates is an example of a first wiring in the second embodiment, a wiring pattern PA2 through which the drive signal COMA1 corresponding to the third drive signal propagates is an example of a fourth wiring in the second embodiment, a wiring pattern PC4 through which the drive signal COMC1 corresponding to the second drive signal propagates is an example of a second wiring in the second embodiment, and a wiring pattern PS4 through which the reference voltage signal VBS1 propagates is an example of a third wiring in the second embodiment.

[0172] As described above, the embodiments and modifications have been explained, but the present invention is not limited to these embodiments, and can be implemented in various modes without departing from the gist thereof. For example, it is also possible to appropriately combine the above-described embodiments.

[0173] The present invention includes a configuration that is substantially the same as the configuration described in the embodiment (for example, a configuration having the same function, method, and result, or a configuration having the same purpose and effect). Further, the present invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. Further, the present invention includes a configuration that exhibits the same operational effect as the configuration described in the embodiment or a configuration that can achieve the same purpose. Further, the present invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

[0174] The following content is derived from the above-described embodiment.

[0175] One aspect of the liquid ejection device is a discharge head that discharges liquid in response to driving of a driving element, A head drive circuit that outputs a first drive signal for driving the drive element so that liquid is ejected and a second drive signal for driving the drive element so that liquid is not ejected; A connection member having one end electrically connected to the head drive circuit and the other end electrically connected to the ejection head; comprising; The connection member includes a first wiring that propagates the first drive signal, a second wiring that propagates the second drive signal, a third wiring that propagates a reference voltage signal that serves as a reference potential for driving the drive element, and a base material on which the first wiring, the second wiring, and the third wiring are provided. The first wiring and the second wiring are provided on a first surface of the base material. The third wiring is provided on a second surface of the base material different from the first surface. In a first direction along the direction from the first surface to the second surface, at least one of the first wiring and the second wiring is positioned overlapping at least a part of the third wiring.

[0176] According to this liquid ejection device, by using a wiring board provided on a base material as a connection member for the first wiring that propagates the first drive signal, the second wiring that propagates the second drive signal, and the third wiring that propagates the reference voltage signal, the effective cross-sectional areas of the first wiring, the second wiring, and the third wiring can be optimized according to the amount of current flowing through the first wiring, the second wiring, and the third wiring. As a result, even when the ejection speed of the liquid is further increased, the possibility of an increase in the first wiring, the second wiring, and the third wiring included in the connection member is reduced. Therefore, the possibility of an increase in the area occupied by the connection member in the liquid ejection device is reduced, and as a result, the possibility of an increase in the size of the liquid ejection device is reduced.

[0177] Further, according to this liquid ejection device, in a first direction along the direction from the first surface to the second surface of the substrate, at least one of the first wiring and the second wiring overlaps at least a part of the third wiring, so that when the first drive signal or the second drive signal propagates through the connection member, the magnetic field generated due to the current generated is canceled out. As a result, the possibility of an overshoot voltage being superimposed on the first drive signal or the second drive signal is reduced, the driving accuracy of the drive element by the first drive signal or the second drive signal is improved, and the liquid ejection accuracy from the ejection head is improved.

[0178] Furthermore, according to this liquid ejection device, a first wiring for propagating a first drive signal, a second wiring for propagating a second drive signal, and a third wiring for propagating a reference voltage signal are provided on one substrate as connection members. Even when the connection member is curved or bent, the relative positional relationship between the first wiring in the connection member and the second drive signal and the third wiring is maintained. As a result, even when the connection member is curved or bent, the inductance component generated due to the current generated when the first drive signal and the second drive signal propagate is reduced.

[0179] In one aspect of the liquid ejection device, The first wiring and the second wiring may be arranged side by side along a third direction that intersects both the first direction and a second direction from one end to the other end along the connection member.

[0180] According to this liquid ejection device, the magnetic field generated due to the current generated when the first drive signal or the second drive signal propagates through the connection member can be more efficiently canceled out. Therefore, the possibility of an overshoot voltage being superimposed on the first drive signal or the second drive signal is further reduced, the driving accuracy of the drive element by the first drive signal or the second drive signal is further improved, and the liquid ejection accuracy from the ejection head is further improved.

[0181] In one aspect of the liquid ejection device, The length of the third wiring in the third direction may be greater than the length of the first wiring in the third direction.

[0182] According to this liquid ejection device, it is possible to more efficiently cancel out the magnetic field caused by the current generated when the first drive signal or the second drive signal propagates through the connection member. This further reduces the risk of an overshoot voltage being superimposed on the first drive signal or the second drive signal, further improves the driving accuracy of the drive element by the first drive signal or the second drive signal, and further improves the ejection accuracy of liquid from the ejection head.

[0183] In one aspect of the liquid ejection device, a length of the first wiring in the third direction is greater than a length of the first wiring in the first direction; The length of the third wiring in the third direction may be greater than the length of the third wiring in the first direction.

[0184] According to this liquid ejection device, the magnetic field caused by the current generated when the first drive signal or the second drive signal propagates through the connection member can be more efficiently cancelled out, which further reduces the risk of an overshoot voltage being superimposed on the first drive signal or the second drive signal, further improves the driving accuracy of the drive element by the first drive signal or the second drive signal, and further improves the ejection accuracy of the liquid from the ejection head.

[0185] In one aspect of the liquid ejection device, the head drive circuit outputs a third drive signal that drives the drive element so as to eject liquid; The connection member may include a fourth wiring that propagates the third drive signal.

[0186] According to this liquid ejection device, the head drive circuit outputs a third drive signal that drives the drive element to eject liquid, in addition to a first drive signal that drives the drive element to eject liquid, thereby enabling fine control of the drive of the drive element.

[0187] In one aspect of the liquid ejection device, The amount of liquid discharged from the discharge head when the third drive signal is supplied to the drive element may be different from the amount of liquid discharged from the discharge head when the first drive signal is supplied to the drive element.

[0188] According to this liquid discharge device, it is possible to finely control the discharge amount of the liquid when the first drive signal and the third drive signal output by the head drive circuit are supplied to the drive element. As a result, it is possible to finely control the discharge amount of the liquid discharged by driving the drive element.

[0189] In one aspect of the liquid discharge device, The fourth wiring may be provided on the first surface.

[0190] In one aspect of the liquid discharge device, The fourth wiring may be provided on the second surface.

[0191] In one aspect of the liquid discharge device, The connection member may have an insulating layer that insulates the first wiring, the second wiring, and the third wiring.

Explanation of Signs

[0192] 1... Liquid discharge device, 2... Control unit, 3... Liquid container, 4... Conveying unit, 5... Discharge unit, 10... Head drive module, 20... Liquid discharge module, 23... Discharge module, 30... Wiring member, 31... Housing, 33... Aggregate substrate, 34... Flow path structure, 35... Head substrate, 37... Distribution flow path, 39... Fixed plate, 41... Conveying motor, 42... Conveying roller, 50... Drive signal output circuit, 52... Drive circuit, 52a... Drive circuit, 52b... Drive circuit, 52c... Drive Moving 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... Collective 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, 600... Discharge 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, 700... Base material, 701, 702, 703, 704... Side, 705, 706... Surface, 710... Heat sink, 714... Opening, 720... Heat conduction member group, 730... Heat conduction member, 770... Cooling fan, 780... Screw, 800... Drive circuit board, 810... Wiring board, 811, 812, 813, 814... Side, 820... Through hole, CB... Pressure chamber, CN1, CN2... Connection part, FC... Wiring member, IL... Insulating layer, Ln1, Ln2... Nozzle row, MN... Manifold, N, N1, N2... Nozzle, P... Medium, PA1, PA2... Wiring pattern, PB1~PB4... Wiring pattern, PC1~PC4... Wiring pattern, PS1~PS5... Wiring pattern, RA... Supply communication path, RB... Supply communication path, RK1, RK2... Pressure chamber communication path, RR... Nozzle communication path, RX... Connection communication path, SH1~SH8... Through hole, Su1, Su2... Flow path plate, TIA, TIB, TIC, TIS, TOA, TOB, TOC, TOS... Terminal, WG1, WG2, WG3, WG4, WG5, WG6... Wiring group

Claims

1. A discharge head that discharges liquid in response to driving of a driving element, a first drive signal having a first drive waveform that drives the drive element so that liquid is discharged in a dot formation cycle in which dots of a desired size are formed on a medium by the liquid discharged from the discharge head, and a second drive signal having a second drive waveform that drives the drive element so that liquid is not discharged in the dot formation cycle and does not include a signal waveform for driving the drive element so that liquid is discharged, and a head drive circuit that outputs the second drive signal, a connection member having one end electrically connected to the head drive circuit and the other end electrically connected to the discharge head, comprising, the connection member includes a first wiring that propagates the first drive signal, a second wiring that propagates the second drive signal, a third wiring that propagates a reference voltage signal that is a reference potential for driving the drive element, and a base material on which the first wiring, the second wiring, and the third wiring are provided, the first wiring and the second wiring are provided on a first surface of the base material, the third wiring is provided on a second surface of the base material different from the first surface, in a first direction along a direction from the first surface toward the second surface, at least one of the first wiring and the second wiring is positioned overlapping at least a part of the third wiring, a liquid discharge device characterized by the above.

2. The first wiring and the second wiring are arranged side by side along a third direction that intersects both the first direction and a second direction from the one end toward the other end along the connection member. The liquid discharge device according to claim 1, characterized by the above.

3. The length of the third wiring in the third direction is greater than the length of the first wiring in the third direction. The liquid discharge device according to claim 2, characterized by the above.

4. The length of the first wiring in the third direction is greater than the length of the first wiring in the first direction, and the length of the third wiring in the third direction is greater than the length of the third wiring in the first direction. The liquid discharge device according to claim 2 or 3, characterized by the above.

5. The head drive circuit outputs a third drive signal for driving the drive element so that liquid is discharged, and the connection member has a fourth wiring that propagates the third drive signal. The liquid discharge device according to any one of claims 1 to 4, characterized by the above.

6. ​ The amount of liquid discharged from the discharge head when the third drive signal is supplied to the drive element is different from the amount of liquid discharged from the discharge head when the first drive signal is supplied to the drive element. The liquid discharge device according to claim 5, characterized in that.

7. The fourth wiring is provided on the first surface. The liquid discharge device according to claim 5 or 6, characterized in that.

8. The fourth wiring is provided on the second surface. The liquid discharge device according to claim 5 or 6, characterized in that.

9. The connection member has an insulating layer that insulates the first wiring, the second wiring, and the third wiring. The liquid discharge device according to any one of claims 1 to 8, characterized in that.

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