Head unit, and liquid discharge device

Abstract

To provide a head unit having a drive circuit that drives an improved piezoelectric element.SOLUTION: A head unit comprises: a first discharge part that includes a first piezoelectric element which drives in response to a first drive signal and discharges liquid through the drive by the first piezoelectric element; a flexible wiring board electrically connected to the first discharge part; and a drive signal output circuit into which a first DC voltage signal with a first voltage value, a second DC voltage signal with a second voltage value and a discharge control signal are input and which outputs the first drive signal. The drive signal output circuit is provided on the flexible wiring board, and outputs the first drive signal with the first DC voltage signal selected or deselected, and with the second DC voltage signal selected or deselected, on the basis of the discharge control signal.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a head unit and a liquid ejection apparatus. [Background technology]

[0002] A known liquid ejection device that ejects liquid uses a driving element such as a piezoelectric element. In such a liquid ejection device, the piezoelectric element is driven in response to a potential difference between a drive signal supplied to one end and a reference potential supplied to the other end, and ejects an amount of liquid in response to the drive of the piezoelectric element.

[0003] For example, Patent Document 1 discloses a liquid ejection device having multiple drive circuits that output drive signals, each drive circuit having a modulation circuit that modulates a basic drive signal and multiple power amplifier circuits that power amplify the signal output by the modulation circuit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-063708 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 is not sufficient for the configuration of a liquid ejection device and a head unit that are equipped with a drive circuit for driving a piezoelectric element, and there is room for improvement. [Means for solving the problem]

[0006] One aspect of the head unit according to the present invention is a first ejection section including a first piezoelectric element that is driven by a first drive signal and that ejects liquid by driving the first piezoelectric element; A flexible wiring board electrically connected to the first discharge unit; a drive signal output circuit that receives a first DC voltage signal having a first voltage value, a second DC voltage signal having a second voltage value, and an ejection control signal, and outputs the first drive signal; Equipped with The drive signal output circuit is provided on the flexible wiring board, and outputs the first drive signal, which selects or deselects the first DC voltage signal and selects or deselects the second DC voltage signal based on the ejection control signal.

[0007] One aspect of the liquid ejection device according to the present invention is to a first ejection section including a first piezoelectric element that is driven by a first drive signal and that ejects liquid by driving the first piezoelectric element; A flexible wiring board electrically connected to the first discharge unit; a drive signal output circuit that receives a first DC voltage signal having a first voltage value, a second DC voltage signal having a second voltage value, and an ejection control signal, and outputs the first drive signal; A control circuit that outputs the ejection control signal; Equipped with The drive signal output circuit is provided on the flexible wiring board, and outputs the first drive signal, which selects or deselects the first DC voltage signal and selects or deselects the second DC voltage signal based on the ejection control signal. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of a schematic structure of a liquid ejection device. [Diagram 2] FIG. 2 is a diagram illustrating an example of a functional configuration of a liquid ejection device. [Diagram 3] FIG. 2 is a diagram showing an example of the structure of a print head. [Figure 4] FIG. 2 is a diagram illustrating an example of a configuration of a drive signal output circuit. [Diagram 5] 4A and 4B are diagrams for explaining a latch signal and a change signal; [Figure 6] FIG. 4 is a diagram illustrating an example of a drive signal. [Figure 7] FIG. 2 is a diagram illustrating an example of a configuration of a waveform selection control circuit. [Figure 8] FIG. 2 is a diagram illustrating an example of a configuration of an output circuit. [Figure 9] 5A and 5B are diagrams for explaining the operation of a drive signal output circuit. [Figure 10] 13A and 13B are diagrams illustrating an example of the operation of a decoder and the signal waveforms of drive signals when print data [SIH, SIL]=[1, 1] is input. [Figure 11] 13A and 13B are diagrams illustrating an example of the operation of a decoder and the signal waveforms of drive signals when print data [SIH, SIL]=[1, 0] is input. [Figure 12] 13A and 13B are diagrams illustrating an example of the operation of a decoder and the signal waveforms of drive signals when print data [SIH, SIL]=[0, 1] is input. [Figure 13] 13A and 13B are diagrams illustrating an example of the operation of a decoder and the signal waveforms of drive signals when print data [SIH, SIL]=[0, 0] is input. [Figure 14] FIG. 13 is a diagram showing an example of the configuration of an output switching circuit 252-1 in a modified example. [Figure 15] FIG. 13 is a diagram showing an example of the configuration of an output switching circuit 252-2 in a modified example. [Figure 16] FIG. 13 is a diagram showing a configuration of an output switching circuit 252-7 of a modified example. [Figure 17] 13 is a diagram showing an example of the relationship between the slope of the signal waveform of the drive signal and a voltage control signal of a modified example. [Figure 18] FIG. 13 is a diagram illustrating an example of a configuration of an output circuit according to a second embodiment. [Figure 19] FIG. 13 is a diagram illustrating an example of a configuration of an output switching circuit according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0010] 1. First embodiment 1.1 Overview of liquid ejection device 1 is a diagram showing an example of a schematic structure of a liquid ejection device 1. The liquid ejection device 1 in the first embodiment is a so-called line printing type inkjet printer that transports a medium P along a transport direction and ejects ink, which is an example of a liquid, onto the transported medium P using print heads 21-1 to 21-7 arranged side by side along a main scanning direction intersecting the transport direction, thereby forming an image on the medium P. Such a liquid ejection device 1 can use any printing target, such as printing paper, a resin film, or a fabric, as the medium P. Note that the liquid ejection device 1 is not limited to a line printing type inkjet printer, and may be a serial printing type inkjet printer.

[0011] As shown in FIG. 1, the liquid ejection device 1 includes an ink container 5, a control unit 10, a head unit 20, and a transport unit 40.

[0012] The ink container 5 stores ink of a plurality of colors to be ejected onto the medium P. Examples of the colors of ink stored in the ink container 5 include black k, cyan c, magenta m, and yellow y. As the ink container 5, an ink cartridge, a bag-shaped ink pack formed of a flexible film, an ink tank that can be refilled with ink, and the like can be used.

[0013] The control unit 10 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 10 controls each element of the liquid ejection device 1 including the head unit 20.

[0014] Head unit 20 has print heads 21-1 to 21-7. Print heads 21-1 to 21-7 are arranged in a staggered pattern in the order of print head 21-1, print head 21-2, print head 21-3, print head 21-4, print head 21-5, print head 21-6, and print head 21-7 along a scanning direction that intersects with the transport direction in which medium P is transported.

[0015] The head unit 20 receives as input a control signal Ctrl-H and a voltage signal VDD output by the control unit 10. The control signal Ctrl-H and the voltage signal VDD are input to each of the print heads 21-1 to 21-7. Ink stored in the ink container 5 is supplied to each of the print heads 21-1 to 21-7 via a tube or the like (not shown). Each of the print heads 21-1 to 21-7 ejects ink supplied from the ink container 5 based on the input control signal Ctrl-H and voltage signal VDD.

[0016] The transport unit 40 includes a transport motor 41 and a transport roller 42. The transport motor 41 is driven to rotate based on a control signal Ctrl-T input from the control unit 10. The transport roller 42 rotates in accordance with the rotational drive of the transport motor 41. As the transport roller 42 rotates, the medium P is transported in the transport direction.

[0017] As described above, in the liquid ejection device 1 of the first embodiment, the control unit 10 controls the transportation of the medium P and the ejection of ink from the head unit 20. As a result, the print heads 21-1 to 21-7 of the head unit 20 eject ink at a timing linked to the transportation of the medium P by the transport unit 40. As a result, the ink ejected from the head unit 20 lands at a desired position on the medium P, and a desired image is formed on the medium P.

[0018] 1.2 Functional configuration of the liquid ejection device Next, a description will be given of the functional configuration of the liquid ejection device 1. Fig. 2 is a diagram showing an example of the functional configuration of the liquid ejection device 1. As shown in Fig. 2, the liquid ejection device 1 includes a control unit 10, a head unit 20, and a transport unit 40.

[0019] The control unit 10 includes a constant voltage output circuit 50 and a control circuit 100 .

[0020] The control circuit 100 includes a processor such as a microcontroller, and is communicatively connected to an external device such as a host computer (not shown) that is provided outside the liquid ejection device 1. An image information signal including image data to be formed on the medium P is input from the external device to the control circuit 100. The control circuit 100 performs predetermined image processing on the input image information signal to generate various data for controlling the liquid ejection device 1 and signals corresponding to the data, and outputs the data to corresponding components.

[0021] The control circuit 100 generates a control signal Ctrl-T for controlling the transport of the medium P, and outputs it to the transport unit 40. This causes the transport motor 41 of the transport unit 40 to rotate, controlling the transport along the transport direction of the medium P. Here, the control signal Ctrl-T output by the control circuit 100 may be converted into a signal by a driver circuit (not shown), and then input to the transport motor 41.

[0022] In addition, based on the input image information signal, the control circuit 100 generates a latch signal LAT, a change signal CH, a clock signal SCK, print data signals SI1 to SI7, and a waveform selection signal WS as control signals Ctrl-H for controlling the head unit 20, and outputs them to the head unit 20.

[0023] The control circuit 100 also outputs a voltage value setting signal VSET to the constant voltage output circuit 50. The constant voltage output circuit 50 generates a constant drive voltage signal VDRV at a voltage value defined by the voltage value setting signal VSET as a voltage signal VDD, and outputs the signal to the head unit 20. Such a constant voltage output circuit 50 may be configured to include an AC / DC converter that converts an AC voltage supplied to the liquid ejection device 1 into a DC voltage, or may be configured to include a DC / DC converter that converts the voltage value of the DC voltage used in the liquid ejection device 1. Here, the constant voltage output circuit 50 of the first embodiment may output a plurality of drive voltage signals VDRV with different voltage values. That is, the constant voltage output circuit 50 may be configured to include at least a plurality of AC / DC converters and / or DC / DC converters.

[0024] Furthermore, the constant voltage output circuit 50 generates a reference voltage signal VBS as a reference potential for driving a piezoelectric element 60 (described later) of the head unit 20 as a voltage signal VDD, and outputs it to the head unit 20. The voltage value of the reference voltage signal VBS output by the constant voltage output circuit 50 may be a constant value defined by the voltage value setting signal VSET, or may be a constant value such as 5.5 V or 6 V that is defined regardless of the voltage value setting signal VSET.

[0025] Here, the voltage values ​​of the drive voltage signal VDRV and the reference voltage signal VBS as the voltage signal VDD output by the constant voltage output circuit 50 being constant includes the case where the voltage values ​​can be regarded as constant when taking into account ripples and noise superimposed on the voltage signal VDD, variations in the electronic components that make up the constant voltage output circuit 50, temperature characteristics, and the like.

[0026] The head unit 20 has print heads 21-1 to 21-7. Furthermore, the print head 21-i (where i is any of 1 to 7) includes a drive signal output circuit 200 and ejection units 600[1] to 600[n].

[0027] The drive signal output circuit 200 includes an integrated circuit device. The drive signal output circuit 200 of the print head 21-i receives the latch signal LAT, change signal CH, clock signal SCK, print data signal SIi, waveform selection signal WS, and drive voltage signal VDRV. Based on the input latch signal LAT, change signal CH, clock signal SCK, print data signal SIi, waveform selection signal WS, and drive voltage signal VDRV, the drive signal output circuit 200 generates drive signals VOUT[1] to VOUT[n] corresponding to each of the ejection sections 600[1] to 600[n], and outputs them to the corresponding ejection sections 600[1] to 600[n]. Details of the configuration and operation of the drive signal output circuit 200 will be described later.

[0028] The drive signal VOUT[j] (j is any of 1 to n) output by the drive signal output circuit 200 is input to one end of the piezoelectric element 60 of the ejection section 600[j]. The reference voltage signal VBS output by the constant voltage output circuit 50 is input to the other end of the piezoelectric element 60 of the ejection section 600[j]. The piezoelectric element 60 of the ejection section 600[j] is driven in response to the potential difference between the drive signal VOUT[j] input to one end and the reference voltage signal VBS input to the other end. Then, an amount of ink corresponding to the drive of the piezoelectric element 60 of the ejection section 600[j] is ejected from the ejection section 600[j]. When the ink ejected from the ejection section 600[j] hits the medium P, a dot is formed at a desired position on the medium P.

[0029] That is, the head unit 20 of this embodiment is equipped with an ejection section 600[1] that includes a piezoelectric element 60 driven by a drive signal VOUT[1] and ejects ink by driving the piezoelectric element 60, an ejection section 600[2] that includes a piezoelectric element 60 driven by a drive signal VOUT[2] and ejects ink by driving the piezoelectric element 60, and an ejection section 600[j] that includes a piezoelectric element 60 driven by a drive signal VOUT[j] and ejects ink by driving the piezoelectric element 60.

[0030] Here, the print heads 21-1 to 21-7 are all of the same configuration, and may be referred to as print head 21 when there is no need to distinguish them. In this case, the description will be made on the assumption that print data signal SI is input to print head 21 as print data signals SI1 to SI7. Also, the ejection units 600[1] to 600[n] of print head 21 are all of the same configuration, and may be referred to simply as ejection unit 600 when there is no need to distinguish them. In this case, the description will be made on the assumption that drive signal VOUT is supplied to ejection unit 600 as drive signals VOUT[1] to VOUT[n].

[0031] 1.3 Print head structure Next, an example of the structure of the print head 21 of the head unit 20 will be described. Here, in the following description, an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other will be used. When defining a direction along the X-axis, the starting point side of an arrow along the illustrated X-axis may be referred to as the -X side, and the tip side as the +X side. When defining a direction along the Y-axis, the starting point side of an arrow along the illustrated Y-axis may be referred to as the -Y side, and the tip side as the +Y side. When defining a direction along the Z-axis, the starting point side of an arrow along the illustrated Z-axis may be referred to as the -Z side, and the tip side as the +Z side.

[0032] Fig. 3 is a diagram showing an example of the structure of the print head 21. Here, Fig. 3 shows a cross section of the print head 21, which has a plurality of ejection portions 600 arranged in two rows along the Y axis, cut along the X axis so as to include at least one ejection portion 600.

[0033] 3, the print head 21 has a head chip 300 including a plurality of ejection portions 600, and a flexible wiring substrate 400 electrically connected to the head chip 300. The head chip 300 also has a nozzle plate 310, a flow path forming substrate 320, a pressure chamber substrate 330, a protection substrate 340, a compliance portion 350, a vibration plate 360, a case 370, and a piezoelectric element 60.

[0034] The nozzle plate 310 has nozzles 651 that eject ink arranged in two rows along the Y axis. The flow path forming substrate 320 defines individual flow paths 614, a communicating flow path 615, and a reservoir 616. The pressure chamber substrate 330 defines a pressure chamber 613. The case 370 defines a reservoir 612 and a liquid inlet 611.

[0035] Ink stored in the ink container 5 is supplied to the head chip 300 via a liquid inlet 611. The ink supplied to the head chip 300 reaches a nozzle 651 via an ink flow path 610 including reservoirs 612, 616, an individual flow path 614, a pressure chamber 613, and a communicating flow path 615. The ink that has reached the nozzle 651 is then ejected as the piezoelectric element 60 is driven.

[0036] Specifically, the ink flow path 610 is defined by stacking the flow path forming substrate 320, the pressure chamber substrate 330, and the case 370 along the Z axis. The ink introduced from the liquid inlet 611 is stored in a reservoir 612 defined by the case 370 and a reservoir 616 defined by the flow path forming substrate 320. The reservoirs 612 and 616 are provided in common for each of the multiple nozzles 651 provided in the nozzle plate 310. The ink stored in the reservoirs 612 and 616 is supplied to the pressure chambers 613 provided individually corresponding to each of the multiple nozzles 651 through the individual flow paths 614 provided individually corresponding to each of the multiple nozzles 651. Then, when pressure is applied to the ink supplied to the pressure chambers 613, the ink stored in the pressure chambers 613 is ejected from the nozzles 651 through the communication flow paths 615.

[0037] That is, the ink flow path 610 has a liquid inlet 611 and reservoirs 612, 616 that are common to multiple nozzles 651, and individual flow paths 614, pressure chambers 613, and communicating flow paths 615 that branch off from the reservoir 616 and are individually provided corresponding to each of the multiple nozzles 651.

[0038] The vibration plate 360 ​​is located on the -Z side of the pressure chamber substrate 330 and is provided so as to seal the pressure chamber 613. A piezoelectric element 60 is provided on the -Z side of the vibration plate 360. The piezoelectric element 60 is composed of a piezoelectric body and a pair of electrodes formed on both sides of the piezoelectric body. A drive signal VOUT output by the drive signal output circuit 200 is supplied to one of the pair of electrodes of the piezoelectric element 60, and a reference voltage signal VBS output by the constant voltage output circuit 50 is supplied to the other of the pair of electrodes of the piezoelectric element 60. Then, the piezoelectric body of the piezoelectric element 60 is displaced according to the potential difference generated between the pair of electrodes of the piezoelectric element 60. That is, the piezoelectric element 60 is driven according to the potential difference between the drive signal VOUT and the reference voltage signal VBS. With the driving of the piezoelectric element 60, the vibration plate 360 ​​on which the piezoelectric element 60 is provided is deformed. Then, the internal pressure of the pressure chamber 613 changes due to the deformation of the vibration plate 360. This applies pressure to the ink supplied to the pressure chamber 613. As a result, the ink stored in the pressure chamber 613 is ejected from the nozzle 651 via the communication flow path 615.

[0039] The nozzle plate 310 is located on the +Z side of the flow path forming substrate 320, and is fixed to the flow path forming substrate 320 so that a plurality of nozzles 651 formed in the nozzle plate 310 communicate with the corresponding communicating flow paths 615 formed in the flow path forming substrate 320. In addition, a compliance section 350 is also fixed to the +Z side of the flow path forming substrate 320. The compliance section 350 is located on the +Z side of the reservoir 616 and the individual flow paths 614, and includes a sealing film 351 and a support 352. The sealing film 351 is a flexible film-like member, and seals the +Z side of the reservoir 616 and the individual flow paths 614. The support 352 supports the outer periphery of the sealing film 351 in a frame shape. The compliance section 350 configured as above protects the head chip 300, and reduces fluctuations in pressure applied to the ink inside the reservoir 616 and inside the communicating flow paths 615.

[0040] Here, the configuration including the piezoelectric element 60 , the vibration plate 360 ​​, the pressure chamber 613 , the individual flow path 614 , the communication flow path 615 , and the nozzle 651 corresponds to the ejection section 600 .

[0041] One end of the flexible wiring board 400 is electrically connected to the diaphragm 360, and the other end is electrically connected to a head substrate (not shown). That is, the other end of the flexible wiring board 400 of each of the print heads 21-1 to 21-7 is electrically connected to the head substrate. A semiconductor device 410 is mounted on the flexible wiring board 400 by COF (Chip On Film). The semiconductor device 410 includes the drive signal output circuit 200 described above.

[0042] The print head 21 has a flexible wiring board 400 electrically connected to the ejection units 600[1] to 600[n], and the drive signal output circuit 200 is provided on the flexible wiring board 400. This makes it possible to shorten the propagation path of the drive signals VOUT[1] to VOUT[n] that the drive signal output circuit 200 outputs to the ejection units 600[1] to 600[n], and reduces the risk of waveform distortion in the drive signals VOUT[1] to VOUT[n] due to the influence of the impedance of the propagation path. This improves the driving accuracy of the piezoelectric elements 60 of each of the ejection units 600[1] to 600[n], and improves the ejection accuracy of ink from the ejection units 600[1] to 600[n].

[0043] In addition, by shortening the propagation paths of the drive signals VOUT[1] to VOUT[n], the distances of the propagation paths of the drive signals VOUT[1] to VOUT[n] can be made substantially equal. That is, the propagation distance of the drive signal VOUT[1] from the drive signal output circuit 200 to the discharge section 600[1], the propagation distance of the drive signal VOUT[2] from the drive signal output circuit 200 to the discharge section 600[2], and the propagation distance of the drive signal VOUT[j] from the drive signal output circuit 200 to the discharge section 600[j] are substantially equal. This reduces the risk of variation in the impedances contributing to each of the drive signals VOUT[1] to VOUT[n]. As a result, the risk of variation occurring in the driving of the piezoelectric elements 60 of each of the ejection sections 600[1] to 600[n] is reduced, and the risk of variation occurring in the ejection of ink from the ejection sections 600[1] to 600[n] is reduced.

[0044] The latch signal LAT, change signal CH, clock signal SCK, print data signals SI1 to SI7, waveform selection signal WS, drive voltage signal VDRV, and reference voltage signal VBS input to the head unit 20 propagate through the head substrate, and are input to a flexible wiring substrate 400 of the corresponding print head 21. Then, the latch signal LAT, change signal CH, clock signal SCK, print data signal SI, waveform selection signal WS, and drive voltage signal VDRV propagate through the flexible wiring substrate 400, and are input to a semiconductor device 410 including a drive signal output circuit 200.

[0045] The semiconductor device 410, which includes the drive signal output circuit 200, generates and outputs drive signals VOUT[1] to VOUT[n] corresponding to the ejection sections 600[1] to 600[n] based on the input latch signal LAT, change signal CH, clock signal SCK, print data signal SI, waveform selection signal WS, and drive voltage signal VDRV.

[0046] The drive signal VOUT output by the semiconductor device 410 propagates through a wiring pattern (not shown) formed on the flexible wiring board 400 and the diaphragm 360, and is supplied to one of a pair of electrodes of the piezoelectric element 60. A reference voltage signal VBS propagated through a wiring pattern (not shown) formed on the flexible wiring board 400 and the diaphragm 360 is supplied to the other of the pair of electrodes of the piezoelectric element 60. This causes the piezoelectric element 60 to drive in response to the potential difference between the drive signal VOUT and the reference voltage signal VBS. Then, an amount of ink corresponding to the drive of the piezoelectric element 60 is ejected from the nozzle 651 of the ejection unit 600.

[0047] 1.4 Configuration and operation of the drive signal output circuit 1.4.1 Configuration of the drive signal output circuit The drive signal output circuit 200 generates drive signals VOUT[1] to VOUT[n] corresponding to each of the ejection sections 600[1] to 600[n] from the drive voltage signal VDRV based on the latch signal LAT, the change signal CH, the clock signal SCK, the print data signals SI1 to SI7, and the waveform selection signal WS, and outputs them to the ejection sections 600[1] to 600[n].

[0048] Fig. 4 is a diagram showing an example of the configuration of the drive signal output circuit 200. As shown in Fig. 4, the drive signal output circuit 200 has a waveform selection control circuit 210, a waveform information storage circuit 230, and output circuits 250[1] to 250[n].

[0049] The waveform information storage circuit 230 includes a non-volatile memory such as a flash memory or an EEPROM (Electronically Erasable Programmable Read Only Memory). The waveform information storage circuit 230 stores information on the signal waveform of the drive signal VOUT output by the drive signal output circuit 200, for example, waveform information that specifies the decoded content in the decoder 216 (described later) according to the signal waveform of the drive signal VOUT output by the drive signal output circuit 200. The waveform information storage circuit 230 reads out waveform information selected by the input waveform selection signal WS, and generates a waveform information signal WI including the read out waveform information. Then, the waveform information storage circuit 230 outputs the generated waveform information signal WI to the waveform selection control circuit 210. That is, the drive signal output circuit 200 has a waveform information storage circuit 230 in which the waveform information of the drive signals VOUT[1] to VOUT[n] is stored.

[0050] The waveform selection control circuit 210 receives the latch signal LAT, the change signals CHA, CHB, CHC, and CHD as the change signal CH, the clock signal SCK, the print data signal SI, and the waveform information signal WI output by the waveform information storage circuit 230. The waveform selection control circuit 210 generates and outputs voltage selection signals S[1] to S[n] based on the input latch signal LAT, the change signals CHA, CHB, CHC, and CHD, the clock signal SCK, the print data signal SI, and the waveform information signal WI.

[0051] The output circuits 250[1] to 250[n] are provided corresponding to the ejection portions 600[1] to 600[n] of the print head 21. The voltage selection signals S[1] to S[n] output by the waveform selection control circuit 210 are input to the output circuits 250[1] to 250[n]. In addition, the drive voltage signals VHV1, VHV2, VHV3, VCV, VBV1, VBV2, and VBV3 serving as the drive voltage signal VDRV are input to the output circuits 250[1] to 250[n]. The output circuits 250[1] to 250[n] select or deselect the drive voltage signals VHV1, VHV2, VHV3, VCV, VBV1, VBV2, and VBV3 based on the corresponding voltage selection signals S[1] to S[n], thereby generating drive signals VOUT[1] to VOUT[n] and outputting them to the corresponding discharge sections 600[1] to 600[n].

[0052] Specifically, the voltage selection signal S[1] output by the waveform selection control circuit 210 is input to the output circuit 250[1]. The output circuit 250[1] generates a drive signal VOUT[1] by selecting or not selecting the drive voltage signals VHV1, VHV2, VHV3, VCV, VBV1, VBV2, and VBV3 based on the input voltage selection signal S[1], and outputs the drive signal VOUT[1] to the discharge unit 600[1]. In addition, the voltage selection signal S[j] output by the waveform selection control circuit 210 is input to the output circuit 250[j]. The output circuit 250[j] generates a drive signal VOUT[j] by selecting or not selecting the drive voltage signals VHV1, VHV2, VHV3, VCV, VBV1, VBV2, and VBV3 based on the input voltage selection signal S[j], and outputs the drive signal VOUT[j] to the discharge unit 600[j].

[0053] In the following description, the voltage values ​​of the drive voltage signal VDRV defined by the voltage value setting signal VSET are as follows: the voltage value of the drive voltage signal VHV1 is referred to as voltage Vh1, the voltage value of the drive voltage signal VHV2 is referred to as voltage Vh2, the voltage value of the drive voltage signal VHV3 is referred to as voltage Vh3, the voltage value of the drive voltage signal VCV is referred to as voltage Vc, the voltage value of the drive voltage signal VBV1 is referred to as voltage Vb1, the voltage value of the drive voltage signal VBV2 is referred to as voltage Vb2, and the voltage value of the drive voltage signal VBV3 is referred to as voltage Vb3. The voltage values ​​of the voltages Vh1, Vh2, Vh3, Vc, Vb1, Vb2, and Vb3 are described in the order of Vh3, Vh2, Vh1, Vc, Vb1, Vb2, and Vb3. That is, voltage Vc is greater than voltages Vb1, Vb2, and Vb3, and voltages Vh1, Vh2, and Vh3 are greater than voltage Vc. Such voltages Vh1, Vh2, Vh3, Vc, Vb1, Vb2, and Vb3 can be changed by voltage value setting signal VSET.

[0054] In the following description, the output circuits 250[1] to 250[n] corresponding to the ejection unit 600 may be referred to as the output circuit 250. In this case, the description will be given on the assumption that the voltage selection signal S is input to the output circuit 250 as the voltage selection signal S[j].

[0055] As described above, the drive voltage signal output circuit 200 of the first embodiment receives as input a drive voltage signal VHV1 having a voltage value of voltage Vh1, a drive voltage signal VHV2 having a voltage value of voltage Vh2, a drive voltage signal VHV3 having a voltage value of voltage Vh3, a drive voltage signal VCV having a voltage value of voltage Vc, a drive voltage signal VBV1 having a voltage value of voltage Vb1, a drive voltage signal VBV2 having a voltage value of voltage Vb2, a drive voltage signal VBV3 having a voltage value of voltage Vb3, and a print data signal SI. The drive signal output circuit 200 outputs drive signals VOUT[1] to VOUT[n] based on a drive voltage signal VHV1 having a voltage value of voltage Vh1, a drive voltage signal VHV2 having a voltage value of voltage Vh2, a drive voltage signal VHV3 having a voltage value of voltage Vh3, a drive voltage signal VCV having a voltage value of voltage Vc, a drive voltage signal VBV1 having a voltage value of voltage Vb1, a drive voltage signal VBV2 having a voltage value of voltage Vb2, a drive voltage signal VBV3 having a voltage value of voltage Vb3, and the print data signal SI.

[0056] Specifically, the drive signal output circuit 200 selects or deselects the drive voltage signal VHV1, selects or deselects the drive voltage signal VHV2, selects or deselects the drive voltage signal VHV3, selects or deselects the drive voltage signal VCV, selects or deselects the drive voltage signal VBV1, selects or deselects the drive voltage signal VBV2, and selects or deselects the drive voltage signal VBV3 based on the print data signal SI, thereby outputting the drive signals VOUT[1] to VOUT[n].

[0057] 1.4.2 Functions of Latch Signal and Change Signal CH Next, the latch signal LAT and the change signals CHA, CHB, CHC, and CHD input to the drive signal output circuit 200 will be described.

[0058] FIG. 5 is a diagram for explaining the latch signal LAT and the change signals CHA, CHB, CHC, and CHD. As shown in FIG. 5, the latch signal LAT is a pulse signal that defines a dot formation period cd at which dots are formed on the medium P. Specifically, the control circuit 100 acquires the transport position of the medium P using an encoder (not shown) or the like. Then, the control circuit 100 outputs a latch signal LAT that temporarily becomes an H level at a predetermined timing synchronized with the acquired transport position of the medium P, thereby defining a dot formation period cd at which dots are formed on the medium P according to the transport position of the medium P. Note that, when the liquid ejection device 1 is an inkjet printer of a serial printing method, the control circuit 100 may define the dot formation period cd by outputting a latch signal that temporarily becomes an H level at a predetermined timing synchronized with the transport position of the medium P, as well as the scanning position of a carriage that carries the print head 21 and moves in the scanning direction.

[0059] The change signal CHA is a pulse signal that divides the dot formation cycle cd into p (p is an integer equal to or greater than 1) periods pa1 to pap. The change signal CHB is a pulse signal that divides the dot formation cycle cd into q (q is an integer equal to or greater than 1) periods pb1 to pbq. The change signal CHC is a pulse signal that divides the dot formation cycle cd into r (r is an integer equal to or greater than 1) periods pc1 to pcr. The change signal CHD is a pulse signal that divides the dot formation cycle cd into s (s is an integer equal to or greater than 1) periods pd1 to pdr. The timing and number at which the change signals CHA, CHB, CHC, and CHD go to H level are controlled by the control circuit 100 in accordance with the signal waveform defined by the waveform selection signal WS. In other words, the control circuit 100 controls the timing at which the change signals CHA, CHB, CHC, and CHD temporarily go to H level in the dot formation cycle cd and the number of times that the change signals CHA, CHB, CHC, and CHD temporarily go to H level in the dot formation cycle cd, thereby independently controlling the number of divisions of the dot formation cycle cd and the lengths of each of the periods pa1~pap, pb1~pbq, pc1~pcr, and pd1~pds.

[0060] 1.4.3 Example of drive signal VOUT Next, an example of the drive signal VOUT output by the drive signal output circuit 200 will be described. Fig. 6 is a diagram showing an example of the drive signal VOUT. As shown in Fig. 6, the drive signal output circuit 200 of the first embodiment outputs a drive signal VOUT including a drive waveform DEP, a drive signal VOUT including a drive waveform BSD, a drive signal VOUT including a drive waveform NVT, and a drive signal VOUT including a drive waveform ND.

[0061] The driving waveform DEP has a constant voltage Vc at time t0 when the latch signal LAT rises, a voltage value drops at time ta1 after time t0, and then becomes constant at voltage Vb3, a voltage value rises at time ta2 after time ta1, and then becomes constant at voltage Vh3, a voltage value drops at time ta3 after time ta2, and then becomes constant at voltage Vc. That is, the driving waveform DEP is a signal waveform whose voltage value changes in the order of voltage Vc, voltage Vb3, voltage Vh3, and voltage Vc in the dot formation period cd. When a driving signal VOUT including such a driving waveform DEP is input to the ejection section 600, the piezoelectric element 60 is driven to draw ink from the reservoir 616 to the pressure chamber 613 during the period from time ta1 to ta2, and is driven to eject the drawn ink from the nozzle 651 during the period from time ta2 to ta3. That is, the driving waveform DEP is a signal waveform that drives the piezoelectric element 60 to eject ink from the ejection section 600.

[0062] The driving waveform BSD has a constant voltage value of Vc at time t0 when the latch signal LAT rises, a voltage value drops at time tb1 after time t0, and then becomes constant at voltage Vb1, and a voltage value rises at time tb2 after time tb1, and then becomes constant at voltage Vc. That is, the driving waveform BSD is a signal waveform whose voltage value changes in the order of voltage Vc, voltage Vb1, and voltage Vc in the dot formation period cd. When a driving signal VOUT including such a driving waveform BSD is input to the ejection unit 600, the piezoelectric element 60 is driven to such an extent that liquid is not ejected from the nozzle 651. As a result, the ink near the nozzle 651 vibrates. This reduces the possibility that the ink near the nozzle 651 of the ejection unit 600 dries and the viscosity increases. That is, the driving waveform BSD is a signal waveform that drives the piezoelectric element 60 so that ink is not ejected from the ejection unit 600.

[0063] The driving waveform NVT has a constant voltage value of Vc at time t0 when the latch signal LAT rises, and the voltage value rises at time tc1 after time t0, and then becomes constant at voltage Vh2, and the voltage value drops at time tc2 after time tc1, and then becomes constant at voltage Vb2, and the voltage value rises at time tc3 after time tc2, and then becomes constant at voltage Vc. That is, the driving waveform NVT is a signal waveform whose voltage value changes in the order of voltage Vc, voltage Vh2, voltage Vb2, and voltage Vc in the dot formation cycle cd. When the driving signal VOUT including such a driving waveform NVT is input to the ejection section 600, the piezoelectric element 60 is driven to such an extent that liquid is not ejected from the nozzle 651 during the period from time ta2 to ta3, thereby generating a predetermined residual vibration in the ink stored in the pressure chamber 613. At this time, a counter electromotive force associated with the residual vibration is generated in the piezoelectric element 60. It is known that the amplitude and period of the back electromotive force generated by the piezoelectric element 60 changes depending on the state of the ejection section 600. The drive signal output circuit 200 determines the state of the ejection section 600 by acquiring the back electromotive force associated with the residual vibration generated in the piezoelectric element 60. In other words, the drive waveform NVT is a signal waveform for inspecting the state of the ejection section 600.

[0064] The drive waveform ND is a signal waveform whose voltage value is constant at voltage Vc during the dot formation cycle cd. When a drive signal VOUT including such a drive waveform ND is input to the ejection section 600, the piezoelectric element 60 is not driven and ink is not ejected from the nozzle 651. In other words, the drive waveform ND is a signal waveform for not driving the piezoelectric element 60 included in the ejection section 600 and for maintaining it in a constant state.

[0065] That is, the drive signal output circuit 200 outputs a drive signal VOUT[1] including a drive waveform DEP that drives the piezoelectric element 60 included in the ejection section 600[1] so that ink is ejected from the ejection section 600[1], a drive signal VOUT[1] including a drive waveform BSD that drives the piezoelectric element 60 included in the ejection section 600[1] so that ink is not ejected from the ejection section 600[1], and a drive signal VOUT[1] including a drive waveform NVT for inspecting the state of the ejection section 600[1].

[0066] As described above, the drive signal output circuit 200 of this embodiment generates a drive signal VOUT including any one of the drive waveform DEP for ejecting ink from the ejection section 600, the drive waveform BSD for vibrating the ejection section 600 to such an extent that ink is not ejected from the ejection section 600, the drive waveform NVT for determining the state of the ejection section 600, and the drive waveform ND for not driving the piezoelectric element 60 included in the ejection section 600, and outputs it to the corresponding ejection section 600. Note that the signal waveform of the drive signal VOUT shown in FIG. 6 is an example and is not limited thereto. In addition, the drive signal output circuit 200 may output a plurality of types of drive waveforms DEP for ejecting ink from the ejection section 600.

[0067] 1.4.4 Configuration of the waveform selection control circuit Next, a description will be given of the configuration of the waveform selection control circuit 210. Fig. 7 is a diagram showing an example of the configuration of the waveform selection control circuit 210. Here, Fig. 7 shows, in addition to the configuration of the waveform selection control circuit 210, output circuits 250[1]-250[n] to which voltage selection signals S[1]-S[n] output by the waveform selection control circuit 210 are input, and discharge units 600[1]-600[n].

[0068] 7, the waveform selection control circuit 210 receives a clock signal SCK, a print data signal SI, a latch signal LAT, change signals CHA, CHB, CHC, CHD, and a waveform information signal WI. The waveform selection control circuit 210 also includes a set of a register 212, a latch circuit 214, and a decoder 216 corresponding to each of the ejection units 600[1] to 600[n]. That is, the waveform selection control circuit 210 includes the same number of sets of registers 212, latch circuits 214, and decoders 216 as the number of n ejection units 600.

[0069] The print data signal SI is a signal synchronized with the clock signal SCK, and includes 2-bit print data [SIH, SIL] in serial for selecting a signal waveform included in the drive signal VOUT output to each of the n ejection units 600 from among the drive waveforms DEP, BSD, NVT, and ND. That is, the print data signal SI includes at least a 2n-bit signal. The print data [SIH, SIL] included in the print data signal SI corresponds to the n ejection units 600 and is held in the register 212.

[0070] Specifically, in the waveform selection control circuit 210, the registers 212 are connected in cascade to configure an n-stage shift register. The print data [SIH, SIL] input serially as the print data signal SI is transferred to the registers 212 in the following stages in sequence in accordance with the clock signal SCK. When the supply of the clock signal SCK is stopped, the print data [SIH, SIL] corresponding to each of the n ejection units 600 is held in the registers 212 corresponding to each of the n ejection units 600. In the following description, in order to distinguish the n registers 212 that configure the shift register, they may be referred to as 1st stage, 2nd stage, ..., nth stage in order from the upstream side to the downstream side along which the print data signal SI is propagated.

[0071] Each of the n latch circuits 214 is provided corresponding to the n registers 212. Each of the latch circuits 214 latches the print data [SIH, SIL] held in each of the n registers 212 at the same time at the rising edge of the latch signal LAT. Then, each of the n latch circuits 214 outputs the latched signal as a latch signal LS[1], LS[2], ..., LS[n] to the corresponding decoder 216. Here, in the following description, the signal latched by the latch circuit 214 among the n latch circuits 214 may be referred to as a latch signal LS, which may be the latch signal LS[1], LS[2], ..., LS[n].

[0072] In addition to the latch signal LS latched by the latch circuit 214, the decoder 216 receives the latch signal LAT, the change signals CHA, CHB, CHC, and CHD, and the waveform information signal WI. The decoder 216 decodes the print data [SIH, SIL] included in the input latch signal LS with the content based on the waveform information signal WI, thereby generating a voltage selection signal S of a predetermined logic level in each of the periods pa1 to pap, pb1 to pbq, pc1 to pcr, and pd1 to pds defined by the latch signal LAT and the change signals CHA, CHB, CHC, and CHD, and outputs the generated voltage selection signal S to the output circuit 250. At this time, the decoder 216 outputs the voltage selection signal S whose L level is the ground potential and whose H level is a voltage value level-shifted to voltage Vh3 or a voltage value greater than voltage Vh3.

[0073] 1.4.5 Output circuit configuration Next, a description will be given of the configuration of the output circuit 250 to which the voltage selection signal S output by the waveform selection control circuit 210 is input. Fig. 8 is a diagram showing an example of the configuration of the output circuit 250. As shown in Fig. 8, the output circuit 250 has output switching circuits 252-1 to 252-7.

[0074] The output switching circuit 252-1 includes a switch sw1a and a constant current circuit ci1. A voltage selection signal S1 as a voltage selection signal S and a drive voltage signal VHV3 are input to the output switching circuit 252-1. The voltage selection signal S1 is input to a control terminal of the switch sw1a. The drive voltage signal VHV3 is input to one terminal of the switch sw1a. The other terminal of the switch sw1a is electrically connected to an input terminal of the constant current circuit ci1.

[0075] When an H-level voltage selection signal S1 is input to the control end of the switch sw1a, the switch sw1a is controlled so that one end and the other end are conductive. As a result, a drive voltage signal VHV3 is supplied to the input end of the constant current circuit ci1. This causes the constant current circuit ci1 to output from its output end a signal with a constant current value based on the voltage Vh3, which is the voltage value of the drive voltage signal VHV3 supplied to the input end, and the voltage value of the output end. Here, the switch sw1a and the constant current circuit ci1 may be formed of separate circuit elements, or may be formed of a single circuit element.

[0076] The output switching circuit 252-2 includes switches sw2a, sw2b and constant current circuits ci2, co2. Voltage selection signals S2a, S2b as the voltage selection signal S and a drive voltage signal VHV2 are input to the output switching circuit 252-2. The voltage selection signal S2a is input to a control terminal of the switch sw2a. The voltage selection signal S2b is input to a control terminal of the switch sw2b. The drive voltage signal VHV2 is input to one terminal of the switch sw2a and one terminal of the switch sw2b. The other terminal of the switch sw2a is electrically connected to an input terminal of the constant current circuit ci2. The other terminal of the switch sw2b is electrically connected to an output terminal of the constant current circuit co2.

[0077] When a voltage selection signal S2a of H level is input to the control end of the switch ws2a, the switch sw2a is controlled so that one end and the other end are conductive. As a result, a drive voltage signal VHV2 is supplied to the input end of the constant current circuit ci2. As a result, the constant current circuit ci2 outputs a signal of a constant current value based on the voltage Vh2, which is the voltage value of the drive voltage signal VHV2 supplied to the input end, and the voltage value of the output end from the output end. When a voltage selection signal S2b of H level is input to the control end of the switch ws2b, the switch sw2b is controlled so that one end and the other end are conductive. As a result, a drive voltage signal VHV2 is supplied to the output end of the constant current circuit co2. As a result, the constant current circuit co2 outputs a signal of a constant current value based on the voltage value of the input end and the voltage Vh2 supplied to the output end from the output end. Here, the switch sw2a and the constant current circuit ci2 may be configured as separate circuit elements, or may be configured as one circuit element. Similarly, the switch sw2b and the constant current circuit co2 may be configured as separate circuit elements, or may be configured as a single circuit element.

[0078] The output switching circuit 252-3 includes switches sw3a and sw3b and constant current circuits ci3 and co3. Voltage selection signals S3a and S3b as the voltage selection signal S and a drive voltage signal VHV1 are input to the output switching circuit 252-3. The voltage selection signal S3a is input to a control terminal of the switch sw3a. The voltage selection signal S3b is input to a control terminal of the switch sw3b. The drive voltage signal VHV1 is input to one terminal of the switch sw3a and one terminal of the switch sw3b. The other terminal of the switch sw3a is electrically connected to an input terminal of the constant current circuit ci3. The other terminal of the switch sw3b is electrically connected to an output terminal of the constant current circuit co3.

[0079] When a voltage selection signal S3a of H level is input to the control end of the switch ws3a, the switch sw3a is controlled so that one end and the other end are conductive. As a result, the drive voltage signal VHV1 is supplied to the input end of the constant current circuit ci3. As a result, the constant current circuit ci3 outputs a signal of a constant current value based on the voltage Vh1, which is the voltage value of the drive voltage signal VHV1 supplied to the input end, and the voltage value of the output end from the output end. When a voltage selection signal S3b of H level is input to the control end of the switch ws3b, the switch sw3b is controlled so that one end and the other end are conductive. As a result, the drive voltage signal VHV1 is supplied to the output end of the constant current circuit co3. As a result, the constant current circuit co3 outputs a signal of a constant current value based on the voltage value of the input end and the voltage Vh1 supplied to the output end from the output end. Here, the switch sw3a and the constant current circuit ci3 may be configured as separate circuit elements or may be configured as one circuit element. Similarly, the switch sw3b and the constant current circuit co3 may be configured as separate circuit elements, or may be configured as a single circuit element.

[0080] The output switching circuit 252-4 includes switches sw4a, sw4b and constant current circuits ci4, co4. Voltage selection signals S4a, S4b as the voltage selection signal S and a drive voltage signal VCV are input to the output switching circuit 252-4. The voltage selection signal S4a is input to a control terminal of the switch sw4a. The voltage selection signal S4b is input to a control terminal of the switch sw4b. The drive voltage signal VCV is input to one terminal of the switch sw4a and one terminal of the switch sw4b. The other terminal of the switch sw4a is electrically connected to an input terminal of the constant current circuit ci4. The other terminal of the switch sw4b is electrically connected to an output terminal of the constant current circuit co4.

[0081] When a voltage selection signal S4a of H level is input to the control end of the switch ws4a, the switch sw4a is controlled so that one end and the other end are conductive. As a result, a drive voltage signal VCV is supplied to the input end of the constant current circuit ci4. As a result, the constant current circuit ci4 outputs a signal of a constant current value based on the voltage Vc, which is the voltage value of the drive voltage signal VCV supplied to the input end, and the voltage value of the output end from the output end. When a voltage selection signal S4b of H level is input to the control end of the switch ws4b, the switch sw4b is controlled so that one end and the other end are conductive. As a result, a drive voltage signal VCV is supplied to the output end of the constant current circuit co4. As a result, the constant current circuit co4 outputs a signal of a constant current value based on the voltage value of the input end and the voltage Vc supplied to the output end from the output end. Here, the switch sw4a and the constant current circuit ci4 may be configured as separate circuit elements, or may be configured as one circuit element. Similarly, the switch sw4b and the constant current circuit co4 may be configured as separate circuit elements, or may be configured as a single circuit element.

[0082] The output switching circuit 252-5 includes switches sw5a and sw5b and constant current circuits ci5 and co5. Voltage selection signals S5a and S5b as the voltage selection signal S and a drive voltage signal VBV1 are input to the output switching circuit 252-5. The voltage selection signal S5a is input to a control terminal of the switch sw5a. The voltage selection signal S5b is input to a control terminal of the switch sw5b. The drive voltage signal VBV1 is input to one terminal of the switch sw5a and one terminal of the switch sw5b. The other terminal of the switch sw5a is electrically connected to an input terminal of the constant current circuit ci5. The other terminal of the switch sw5b is electrically connected to an output terminal of the constant current circuit co5.

[0083] When a voltage selection signal S5a of H level is input to the control end of the switch ws5a, the switch sw5a is controlled so that one end and the other end are conductive. As a result, the drive voltage signal VBV1 is supplied to the input end of the constant current circuit ci5. As a result, the constant current circuit ci5 outputs a signal of a constant current value based on the voltage Vb1, which is the voltage value of the drive voltage signal VBV1 supplied to the input end, and the voltage value of the output end from the output end. When a voltage selection signal S5b of H level is input to the control end of the switch ws5b, the switch sw5b is controlled so that one end and the other end are conductive. As a result, the drive voltage signal VBV1 is supplied to the output end of the constant current circuit co5. As a result, the constant current circuit co5 outputs a signal of a constant current value based on the voltage value of the input end and the voltage Vb1 supplied to the output end from the output end. Here, the switch sw5a and the constant current circuit ci5 may be configured as separate circuit elements or may be configured as one circuit element. Similarly, the switch sw5b and the constant current circuit co5 may be configured as separate circuit elements, or may be configured as a single circuit element.

[0084] The output switching circuit 252-6 includes switches sw6a and sw6b and constant current circuits ci6 and co6. Voltage selection signals S6a and S6b as the voltage selection signal S and a drive voltage signal VBV2 are input to the output switching circuit 252-6. The voltage selection signal S6a is input to a control terminal of the switch sw6a. The voltage selection signal S6b is input to a control terminal of the switch sw6b. The drive voltage signal VBV2 is input to one terminal of the switch sw6a and one terminal of the switch sw6b. The other terminal of the switch sw6a is electrically connected to an input terminal of the constant current circuit ci6. The other terminal of the switch sw6b is electrically connected to an output terminal of the constant current circuit co6.

[0085] When a voltage selection signal S6a of H level is input to the control end of the switch ws6a, the switch sw6a is controlled so that one end and the other end are conductive. As a result, the drive voltage signal VBV2 is supplied to the input end of the constant current circuit ci6. As a result, the constant current circuit ci6 outputs a signal of a constant current value based on the voltage Vb2, which is the voltage value of the drive voltage signal VBV2 supplied to the input end, and the voltage value of the output end from the output end. When a voltage selection signal S6b of H level is input to the control end of the switch ws6b, the switch sw6b is controlled so that one end and the other end are conductive. As a result, the drive voltage signal VBV2 is supplied to the output end of the constant current circuit co6. As a result, the constant current circuit co6 outputs a signal of a constant current value based on the voltage value of the input end and the voltage Vb2 supplied to the output end from the output end. Here, the switch sw6a and the constant current circuit ci6 may be configured as separate circuit elements, or may be configured as one circuit element. Similarly, the switch sw6b and the constant current circuit co6 may be configured as separate circuit elements, or may be configured as a single circuit element.

[0086] The output switching circuit 252-7 includes a switch sw7b and a constant current circuit co7. A voltage selection signal S7 as the voltage selection signal S and a drive voltage signal VBV3 are input to the output switching circuit 252-7. The voltage selection signal S7 is input to a control terminal of the switch sw7b. The drive voltage signal VBV3 is input to one terminal of the switch sw7b. The other terminal of the switch sw7b is electrically connected to the output terminal of the constant current circuit co7.

[0087] When a voltage selection signal S7 of H level is input to the control terminal of the switch ws7b, the switch sw7b is controlled so that one terminal and the other terminal are conductive. As a result, the drive voltage signal VBV3 is supplied to the output terminal of the constant current circuit co7. This causes the constant current circuit co7 to output a signal of a constant current value based on the voltage value of the input terminal and the voltage Vb3, which is the voltage value of the drive voltage signal VBV3 supplied to the output terminal. Here, the switch sw7b and the constant current circuit co7 may be formed of separate circuit elements or may be formed of a single circuit element.

[0088] The outputs of the output switching circuits 252-1 to 252-7 are commonly connected. The output circuit 250 outputs the signals generated at the outputs of the commonly connected output switching circuits 252-1 to 252-7 as the drive signal VOUT.

[0089] As described above, the output circuit 250 generates the drive signal VOUT by switching whether or not the input drive voltage signals VHV1, VHV2, VHV3, VCV, VBV1, VBV2, and VBV3 are output based on the logic level of the corresponding voltage selection signal S, and outputs the drive signal VOUT to the corresponding discharge section 600. That is, the constant current circuits ci1, ci2, ci3, ci4, ci5, and ci6 output currents based on the voltage values ​​of the drive voltage signals VHV3, VHV2, VHV1, VCV, VBV1, and VBV2 and the voltage value of the drive signal VOUT to the discharge section 600. Such constant current circuits ci1, ci2, ci3, ci4, ci5, and ci6 can be configured to include, for example, P-channel type FETs (Field Effect Transistors). Furthermore, the constant current circuits co2, co3, co4, co5, co6, and co7 draw currents based on the voltage value of the drive signal VOUT and the voltage values ​​of the drive voltage signals VHV3, VHV2, VHV1, VCV, VBV1, and VBV2 from the discharge unit 600. Such constant current circuits co2, co3, co4, co5, co6, and co7 can be configured to include, for example, an N-channel type FET (Field Effect Transistor).

[0090] That is, the output switching circuit 252-1 includes a P-channel FET, the output switching circuits 252-2 to 252-6 include P-channel FETs and N-channel FETs, and the output switching circuit 252-7 includes an N-channel FET.

[0091] As described above, the drive signal output circuit 200 includes an output switching circuit 252-1 that outputs a signal of a constant current value based on the drive voltage signal VHV3, an output switching circuit 252-2 that outputs a signal of a constant current value based on the drive voltage signal VHV2, an output switching circuit 252-3 that outputs a signal of a constant current value based on the drive voltage signal VHV1, an output switching circuit 252-4 that outputs a signal of a constant current value based on the drive voltage signal VCV, an output switching circuit 252-5 that outputs a signal of a constant current value based on the drive voltage signal VBV1, an output switching circuit 252-6 that outputs a signal of a constant current value based on the drive voltage signal VBV2, and an output switching circuit 252-7 that outputs a signal of a constant current value based on the drive voltage signal VBV3.

[0092] Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the output switching circuit 252-1 outputs a signal of a constant current value based on the drive voltage signal VHV3, whether the output switching circuit 252-2 outputs a signal of a constant current value based on the drive voltage signal VHV2, whether the output switching circuit 252-3 outputs a signal of a constant current value based on the drive voltage signal VHV1, whether the output switching circuit 252-4 outputs a signal of a constant current value based on the drive voltage signal VCV, whether the output switching circuit 252-5 outputs a signal of a constant current value based on the drive voltage signal VBV1, whether the output switching circuit 252-6 outputs a signal of a constant current value based on the drive voltage signal VBV2, and whether the output switching circuit 252-7 outputs a signal of a constant current value based on the drive voltage signal VBV3. In other words, the waveform selection control circuit 210 acquires the waveform information signal WI, and controls the output switching circuits 252-1 to 252-7 based on the acquired waveform information signal WI and the print data signal SI.

[0093] As a result, the output switching circuit 252-1 switches between whether to output a signal of a constant current value based on the drive voltage signal VHV3 by selecting or not selecting the drive voltage signal VHV3, the output switching circuit 252-2 switches between whether to output a signal of a constant current value based on the drive voltage signal VHV2 by selecting or not selecting the drive voltage signal VHV2, the output switching circuit 252-3 switches between whether to output a signal of a constant current value based on the drive voltage signal VHV3 by selecting or not selecting the drive voltage signal VHV3, and the output switching circuit 252-4 selects or not selects the drive voltage signal VCV. The output switching circuit 252-5 switches whether or not to output a signal of a constant current value based on the drive voltage signal VBV1 by selecting or deselecting the drive voltage signal VBV1, the output switching circuit 252-6 switches whether or not to output a signal of a constant current value based on the drive voltage signal VBV2 by selecting or deselecting the drive voltage signal VBV2, and the output switching circuit 252-7 switches whether or not to output a signal of a constant current value based on the drive voltage signal VBV3 by selecting or deselecting the drive voltage signal VBV3.

[0094] As a result, the drive signal output circuit 200 outputs drive signals VOUT[1] to VOUT[n] corresponding to a constant current value signal based on the drive voltage signal VHV3, a constant current value signal based on the drive voltage signal VHV2, a constant current value signal based on the drive voltage signal VHV1, a constant current value signal based on the drive voltage signal VCV, a constant current value signal based on the drive voltage signal VBV1, a constant current value signal based on the drive voltage signal VBV2, and a constant current value signal based on the drive voltage signal VBV3.

[0095] Here, the output switching circuit 252-1, which switches whether to output a signal based on the drive voltage signal VHV3 with the largest voltage value among the drive voltage signals VHV1, VHV2, VHV3, VCV, VBV1, VBV2, and VBV3, may include a circuit that outputs a constant current signal from the output terminal based on the voltage value of the input terminal and the voltage Vh3 supplied to the output terminal, in addition to the constant current circuit ci1 that outputs a constant current signal from the output terminal based on the voltage value of the input terminal and the voltage Vh3 supplied to the output terminal. Furthermore, the output switching circuit 252-7, which switches whether to output a signal based on the driving voltage signal VBV3 having the smallest voltage value among the driving voltage signals VHV1, VHV2, VHV3, VCV, VBV1, VBV2, and VBV3, may include a circuit that outputs a signal of a constant current value based on the voltage Vb3 supplied to the input terminal and the voltage value of the output terminal from the output terminal, in addition to the constant current circuit co7 that outputs a signal of a constant current value based on the voltage value of the input terminal and the voltage Vb3 supplied to the output terminal from the output terminal. This allows the output switching circuits 252-1 to 252-7 to all have the same configuration, and the manufacturing cost of the semiconductor device 410 including the output switching circuits 252-1 to 252-7 to be reduced.

[0096] 1.4.6 Operation of the drive signal output circuit The operation of the drive signal output circuit 200 will be described. FIG. 9 is a diagram for explaining the operation of the drive signal output circuit 200. The print data [SIH, SIL] included in the print data signal SI is serially input to the drive signal output circuit 200 in synchronization with the clock signal SCK. The print data [SIH, SIL] input to the drive signal output circuit 200 is sequentially transferred by the registers 212 corresponding to the discharge units 600[1] to 600[n] in synchronization with the clock signal SCK. Thereafter, the supply of the clock signal SCK is stopped, and the print data [SIH, SIL] corresponding to each of the discharge units 600[1] to 600[n] is held in each of the registers 212. Note that in the first embodiment, the print data [SIH, SIL] included in the print data signal SI is input in the order corresponding to the discharge unit 600[n], discharge unit 600[n-1], ..., discharge unit 600[2], and discharge unit 600[1].

[0097] Thereafter, when the latch signal LAT rises, the latch circuits 214 simultaneously latch the print data [SIH, SIL] held in the register 212 as a latch signal LS. Then, the latch circuits 214 input the latch signal LS including the latched print data [SIH, SIL] to the corresponding decoder 216. Each of the decoders 216 decodes the input latch signal LS based on the waveform information signal WI input from the waveform information storage circuit 230 to generate a voltage selection signal S and output it to the output circuit 250.

[0098] Specifically, the latch circuit 214 corresponding to the ejection unit 600[1] latches the print data [SIH, SIL] held in the register 212 corresponding to the ejection unit 600[1] as a latch signal LS[1], and inputs the latched latch signal LS[1] to the decoder 216 corresponding to the ejection unit 600[1]. The decoder 216 corresponding to the ejection unit 600[1] decodes the latch signal LS[1] based on the waveform information signal WI input from the waveform information storage circuit 230 to generate voltage selection signals S1, S2a, S2b, S3a, S3b, S4a, S4b, S5a, S5b, S6a, S6b, and S7 as the voltage selection signal S[1], and outputs them to the output circuit 250[1].

[0099] Similarly, the latch circuit 214 corresponding to the discharge unit 600[j] latches the print data [SIH, SIL] held in the register 212 corresponding to the discharge unit 600[j] as a latch signal LS[j], and inputs the latched latch signal LS[j] to the decoder 216 corresponding to the discharge unit 600[j]. The decoder 216 corresponding to the discharge unit 600[j] decodes the latch signal LS[j] based on the waveform information signal WI input from the waveform information storage circuit 230, thereby generating voltage selection signals S1, S2a, S2b, S3a, S3b, S4a, S4b, S5a, S5b, S6a, S6b, and S7 as the voltage selection signal S[j], and outputs them to the output circuit 250[j].

[0100] Next, a specific example of the decoded contents in the decoder 216 will be described. Here, the drive signal output circuit 200 of the liquid ejection device 1 of the first embodiment will be described as outputting a drive signal VOUT including a drive waveform DEP to the corresponding ejection section 600 when the print data is [SIH, SIL]=[1,1], outputting a drive signal VOUT including a drive waveform BSD to the corresponding ejection section 600 when the print data is [SIH, SIL]=[1,0], outputting a drive signal VOUT including a drive waveform NVT to the corresponding ejection section 600 when the print data is [SIH, SIL]=[0,1], and outputting a drive signal VOUT including a drive waveform ND to the corresponding ejection section 600 when the print data is [SIH, SIL]=[0,0].

[0101] 10 is a diagram showing an example of the operation of the decoder 216 and the signal waveform of the drive signal VOUT when print data [SIH, SIL]=[1,1] is input. As shown in FIG. 10, when a latch signal LS including print data [SIH, SIL]=[1,1] is input, the decoder 216 generates voltage selection signals S1, S2a, S2b, S3a, S3b, S4a, S4b, S5a, S5b, S6a, S6b, and S7 as voltage selection signals S of predetermined logic levels in each of periods pa1 to pa4 defined by the latch signal LAT and the change signal CHA, and outputs them to the output circuit 250.

[0102] Specifically, the period pa1 starts when the latch signal LAT rises. In the period pa1, the decoder 216 sets the logic level of the voltage selection signal S4b to be output at the H level and the other at the L level. That is, in the period pa1, the switch sw4b of the output switching circuit 252-4 is controlled so that one end and the other end are conductive. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value is constant at the voltage Vc. Note that, in the period pa1, the decoder 216 may set the logic level of the voltage selection signal S4a to be output at the H level and the other at the L level. That is, in the period pa1, the switch sw4a of the output switching circuit 252-4 may be controlled so that one end and the other end are conductive.

[0103] Then, after the latch signal LAT rises, the change signal CHA rises next, starting the period pa2. In the period pa2, the decoder 216 sets the logic level of the voltage selection signal S7 to the H level and the other to the L level. That is, in the period pa2, the switch sw4b of the output switching circuit 252-4 is controlled so that one end and the other end are non-conductive, and the switch sw7b of the output switching circuit 252-7 is controlled so that one end and the other end are conductive. Therefore, the constant current circuit co7 outputs a signal of a constant current value based on the potential difference between the voltage value of the drive signal VOUT supplied to the input terminal and the voltage Vb3 supplied to the output terminal. In other words, the output switching circuit 252-7 draws in a signal of a constant current value based on the potential difference between the voltage value of the drive signal VOUT and the voltage Vb3. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value decreases from the voltage Vc toward the voltage Vb3. When the voltage value of the drive signal VOUT supplied to the input terminal of the constant current circuit co7 becomes the voltage Vb3, the constant current circuit co7 stops outputting the signal with the constant current value. As a result, the voltage value of the drive signal VOUT output by the output circuit 250 becomes constant at the voltage Vb3.

[0104] Then, the change signal CHA rises, and the period pa3 starts. In the period pa3, the decoder 216 sets the logic level of the voltage selection signal S1 to the H level and the other to the L level. That is, in the period pa3, the switch sw7b of the output switching circuit 252-7 is controlled so that one end and the other end are not conductive, and the switch sw1a of the output switching circuit 252-1 is controlled so that one end and the other end are conductive. Therefore, the constant current circuit ci1 outputs a signal of a constant current value based on the potential difference between the signal whose voltage value is the voltage Vh3 supplied to the input terminal and the voltage value of the drive signal VOUT supplied to the output terminal. In other words, the output switching circuit 252-1 outputs a signal of a constant current value based on the potential difference between the voltage Vh3 and the voltage value of the drive signal VOUT. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value increases from the voltage Vb3 toward the voltage Vh3. Then, the voltage value of the drive signal VOUT supplied to the output terminal of the constant current circuit ci1 becomes the voltage Vh3, so that the constant current circuit ci1 stops outputting the signal with the constant current value. As a result, the voltage value of the drive signal VOUT output by the output circuit 250 becomes constant at the voltage Vh3.

[0105] Then, the change signal CHA rises, and the period pa4 starts. In the period pa4, the decoder 216 sets the logic level of the voltage selection signal S4b to the H level and the other to the L level. That is, in the period pa4, the switch sw1a of the output switching circuit 252-1 is controlled so that one end and the other end are not conductive, and the switch sw4b of the output switching circuit 252-4 is controlled so that one end and the other end are conductive. Therefore, the constant current circuit co4 outputs a signal of a constant current value based on the potential difference between the voltage value of the drive signal VOUT supplied to the input terminal and the signal whose voltage value is voltage Vc supplied to the output terminal. In other words, the output switching circuit 252-4 draws in a signal of a constant current value based on the potential difference between the voltage value of the drive signal VOUT and the voltage Vc. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value decreases from voltage Vh3 toward voltage Vc. When the voltage value of the drive signal VOUT supplied to the input terminal of the constant current circuit co4 becomes the voltage Vc, the constant current circuit co4 stops outputting the signal with the constant current value. As a result, the voltage value of the drive signal VOUT output by the output circuit 250 becomes constant at the voltage Vc.

[0106] Thereafter, the latch signal LAT rises, and the dot formation cycle cd ends. As a result, when print data [SIH, SIL]=[1, 1] is input, the drive signal output circuit 200 generates a drive signal VOUT including the drive waveform DEP shown in FIG. 6 in the dot formation cycle cd, and outputs it to the corresponding discharge section 600. Here, as shown in FIG. 10, the timing at which the change signal CHA that specifies the end of the period pa1 rises corresponds to the time ta1 shown in FIG. 6, the timing at which the change signal CHA that specifies the end of the period pa2 rises corresponds to the time ta2 shown in FIG. 6, and the timing at which the change signal CHA that specifies the end of the period pa3 rises corresponds to the time ta3 shown in FIG. 6.

[0107] 11 is a diagram showing an example of the operation of the decoder 216 and the signal waveform of the drive signal VOUT when print data [SIH, SIL]=[1, 0] is input. As shown in FIG. 11, when a latch signal LS including print data [SIH, SIL]=[1, 0] is input, the decoder 216 generates voltage selection signals S1, S2a, S2b, S3a, S3b, S4a, S4b, S5a, S5b, S6a, S6b, and S7 as voltage selection signals S of predetermined logic levels during each of periods pb1 to pb3 defined by the latch signal LAT and the change signal CHB, and outputs them to the output circuit 250.

[0108] Specifically, the period pb1 starts when the latch signal LAT rises. In the period pb1, the decoder 216 sets the logic level of the voltage selection signal S4a to be output at the H level and the other at the L level. That is, in the period pb1, the switch sw4a in the output switching circuit 252-4 is controlled so that one end and the other end are conductive. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value is constant at the voltage Vc. Note that, in the period pb1, the decoder 216 may set the logic level of the voltage selection signal S4b to be output at the H level and the other at the L level. That is, in the period pb1, the switch sw4b in the output switching circuit 252-4 may be controlled so that one end and the other end are conductive.

[0109] Then, after the latch signal LAT rises, the change signal CHB rises next, starting the period pb2. In the period pb2, the decoder 216 sets the logic level of the voltage selection signal S5b to the H level and the other to the L level. That is, in the period pb2, the switch sw4a of the output switching circuit 252-4 is controlled so that one end and the other end are not conductive, and the switch sw5b of the output switching circuit 252-5 is controlled so that one end and the other end are conductive. Therefore, the constant current circuit co5 outputs a signal of a constant current value based on the potential difference between the voltage value of the drive signal VOUT supplied to the input terminal and the voltage Vb1 supplied to the output terminal. In other words, the output switching circuit 252-5 draws in a signal of a constant current value based on the potential difference between the voltage value of the drive signal VOUT and the voltage Vb1. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value decreases from the voltage Vc toward the voltage Vb1. When the voltage value of the drive signal VOUT supplied to the input terminal of the constant current circuit co5 becomes the voltage Vb1, the constant current circuit co5 stops outputting the signal with the constant current value. As a result, the voltage value of the drive signal VOUT output by the output circuit 250 becomes constant at the voltage Vb1.

[0110] Then, the change signal CHB rises, and the period pb3 starts. In the period pb3, the decoder 216 sets the logic level of the voltage selection signal S4a to the H level and the other to the L level. That is, in the period pb3, the switch sw5b of the output switching circuit 252-5 is controlled so that one end and the other end are not conductive, and the switch sw4a of the output switching circuit 252-4 is controlled so that one end and the other end are conductive. Therefore, the constant current circuit ci4 outputs a signal of a constant current value based on the potential difference between the signal whose voltage value is the voltage Vb1 supplied to the input terminal and the voltage value of the drive signal VOUT supplied to the output terminal. In other words, the output switching circuit 252-4 outputs a signal of a constant current value based on the potential difference between the voltage Vc and the voltage value of the drive signal VOUT. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value increases from the voltage Vb1 toward the voltage Vc. Then, when the voltage value of the drive signal VOUT supplied to the output terminal of the constant current circuit ci4 becomes the voltage Vc, the constant current circuit ci4 stops outputting the signal with the constant current value. As a result, the voltage value of the drive signal VOUT output by the output circuit 250 becomes constant at the voltage Vc.

[0111] Thereafter, the latch signal LAT rises, ending the dot formation cycle cd. As a result, when print data [SIH, SIL]=[1, 0] is input, the drive signal output circuit 200 generates a drive signal VOUT including the drive waveform BSD shown in FIG. 6 during the dot formation cycle cd, and outputs it to the corresponding discharge section 600. Here, as shown in FIG. 11, the timing at which the change signal CHB that defines the end of the period pb1 rises corresponds to time tb1 shown in FIG. 6, and the timing at which the change signal CHB that defines the end of the period pb2 rises corresponds to time tb2 shown in FIG. 6.

[0112] 12 is a diagram showing an example of the operation of the decoder 216 and the signal waveform of the drive signal VOUT when print data [SIH, SIL]=[0, 1] is input. As shown in FIG. 12, when a latch signal LS including print data [SIH, SIL]=[0, 1] is input, the decoder 216 generates voltage selection signals S1, S2a, S2b, S3a, S3b, S4a, S4b, S5a, S5b, S6a, S6b, and S7 as voltage selection signals S of predetermined logic levels during each of periods pc1 to pc4 defined by the latch signal LAT and the change signal CHC, and outputs them to the output circuit 250.

[0113] Specifically, the period pc1 starts when the latch signal LAT rises. In the period pc1, the decoder 216 sets the logic level of the voltage selection signal S4a to be output at the H level and the other at the L level. That is, in the period pc1, the switch sw4a in the output switching circuit 252-4 is controlled so that one end and the other end are conductive. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value is constant at the voltage Vc. Note that, in the period pc1, the decoder 216 may set the logic level of the voltage selection signal S4b to be output at the H level and the other at the L level. That is, in the period pc1, the switch sw4b in the output switching circuit 252-4 may be controlled so that one end and the other end are conductive.

[0114] Then, after the latch signal LAT rises, the change signal CHC rises next, starting the period pc2. During the period pc2, the decoder 216 sets the logic level of the voltage selection signal S2a to the H level and the other to the L level. That is, during the period pa2, the switch sw4a of the output switching circuit 252-4 is controlled so that one end and the other end are non-conductive, and the switch sw2a of the output switching circuit 252-2 is controlled so that one end and the other end are conductive. Therefore, the constant current circuit ci2 outputs a signal of a constant current value based on the potential difference between the voltage Vh2 supplied to the input terminal and the voltage value of the drive signal VOUT supplied to the output terminal. In other words, the output switching circuit 252-2 outputs a signal of a constant current value based on the potential difference between the voltage Vh2 and the voltage value of the drive signal VOUT. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value increases from the voltage Vc toward the voltage Vh2. Then, when the voltage value of the drive signal VOUT supplied to the input terminal of the constant current circuit ci2 becomes the voltage Vh2, the constant current circuit ci2 stops outputting the signal with the constant current value. As a result, the voltage value of the drive signal VOUT output by the output circuit 250 becomes constant at the voltage Vh2.

[0115] Then, the change signal CHC rises next, and the period pc3 starts. During the period pc3, the decoder 216 sets the logic level of the voltage selection signal S6b to the H level and the other to the L level. That is, during the period pc3, the switch sw2a of the output switching circuit 252-2 is controlled so that one end and the other end are not conductive, and the switch sw6b of the output switching circuit 252-6 is controlled so that one end and the other end are conductive. Therefore, the constant current circuit co6 outputs a signal of a constant current value based on the potential difference between the voltage value of the drive signal VOUT supplied to the input terminal and the voltage value of the drive signal VOUT supplied to the output terminal and the voltage Vb2. In other words, the output switching circuit 252-6 draws in a signal of a constant current value based on the potential difference between the voltage value of the drive signal VOUT and the voltage Vb2. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value decreases from the voltage Vh2 toward the voltage Vb2. When the voltage value of the drive signal VOUT supplied to the output terminal of the constant current circuit co6 becomes the voltage Vb2, the constant current circuit co6 stops outputting the signal with the constant current value. As a result, the voltage value of the drive signal VOUT output by the output circuit 250 becomes constant at the voltage Vb2.

[0116] Then, the change signal CHC rises, starting the period pc4. During the period pc4, the decoder 216 sets the logic level of the voltage selection signal S4a to the H level and the other to the L level. That is, during the period pc4, the switch sw6b of the output switching circuit 252-6 is controlled so that one end and the other end are not conductive, and the switch sw4a of the output switching circuit 252-4 is controlled so that one end and the other end are conductive. Therefore, the constant current circuit ci4 outputs a signal with a constant current value based on the potential difference between the voltage Vc supplied to the input terminal and the voltage value of the drive signal VOUT supplied to the output terminal. In other words, the output switching circuit 252-4 outputs a signal with a constant current value based on the potential difference between the voltage Vb2 and the voltage value of the drive signal VOUT. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value increases from the voltage Vb2 toward the voltage Vc. Then, when the voltage value of the drive signal VOUT supplied to the output terminal of the constant current circuit ci4 becomes the voltage Vc, the constant current circuit ci4 stops outputting the signal with the constant current value. As a result, the voltage value of the drive signal VOUT output by the output circuit 250 becomes constant at the voltage Vc.

[0117] Thereafter, the latch signal LAT rises, and the dot formation cycle cd ends. As a result, when print data [SIH, SIL]=[0, 1] is input, the drive signal output circuit 200 generates a drive signal VOUT including the drive waveform NVT shown in Fig. 6 during the dot formation cycle cd, and outputs it to the corresponding discharge section 600. Here, as shown in Fig. 12, the timing at which the change signal CHC that defines the end of the period pc1 rises corresponds to time tc1 shown in Fig. 6, the timing at which the change signal CHC that defines the end of the period pc2 rises corresponds to time tc2 shown in Fig. 6, and the timing at which the change signal CHC that defines the end of the period pc3 rises corresponds to time tc3 shown in Fig. 6.

[0118] 13 is a diagram showing an example of the operation of the decoder 216 and the signal waveform of the drive signal VOUT when print data [SIH, SIL]=[0,0] is input. As shown in FIG. 13, when a latch signal LS including print data [SIH, SIL]=[0,0] is input, the decoder 216 generates voltage selection signals S1, S2a, S2b, S3a, S3b, S4a, S4b, S5a, S5b, S6a, S6b, and S7 as voltage selection signals S of a predetermined logic level during a period pd1 defined by the latch signal LAT and the change signal CHD, and outputs them to the output circuit 250.

[0119] Specifically, the period pd1 starts when the latch signal LAT rises. In the period pd1, the decoder 216 sets the logic level of the voltage selection signal S4a to be output at the H level and the other at the L level. That is, in the period pd1, the switch sw4a in the output switching circuit 252-4 is controlled so that one end and the other end are conductive. As a result, the output circuit 250 outputs the drive signal VOUT whose voltage value is constant at the voltage Vc. Note that, in the period pd1, the decoder 216 may set the logic level of the voltage selection signal S4b to be output at the H level and the other at the L level. That is, in the period pd1, the switch sw4b in the output switching circuit 252-4 may be controlled so that one end and the other end are conductive.

[0120] After that, the latch signal LAT rises, and the dot formation cycle cd ends. As a result, when print data [SIH, SIL]=[0,0] is input, the drive signal output circuit 200 generates a drive signal VOUT including a drive waveform ND in the dot formation cycle cd and outputs it to the corresponding ejection section 600.

[0121] As described above, the drive signal output circuit 200 of the first embodiment selects or deselects each of the drive voltage signals VHV1, VHV2, VHV3, VCV, VBV1, VBV2, and VBV3 as the drive voltage signal VDRV based on the latch signal LAT, change signal CH, clock signal SCK, print data signal SI, and waveform selection signal WS, thereby generating a drive signal VOUT corresponding to the voltage values ​​of the drive waveforms DEP, BSD, NVT, and ND, and outputs it to the corresponding ejection section 600.

[0122] 1.5 Effects In the liquid ejection device 1 and head unit 20 of the first embodiment configured as described above, the drive signal output circuit 200 includes an output switching circuit 252-1 that outputs a signal of a constant current value based on a drive voltage signal VHV3 having a voltage value of voltage Vh3, an output switching circuit 252-2 that outputs a signal of a constant current value based on a drive voltage signal VHV2 having a voltage value of voltage Vh2, an output switching circuit 252-3 that outputs a signal of a constant current value based on a drive voltage signal VHV1 having a voltage value of voltage Vh1, and an output switching circuit 252-4 that outputs a signal of a constant current value based on a drive voltage signal VCV having a voltage value of voltage Vc. The output switching circuit 252-4 outputs a signal of a current value, an output switching circuit 252-5 outputs a signal of a constant current value based on a drive voltage signal VBV1 having a voltage value of voltage Vb1, an output switching circuit 252-6 outputs a signal of a constant current value based on a drive voltage signal VBV2 having a voltage value of voltage Vb2, an output switching circuit 252-7 outputs a signal of a constant current value based on a drive voltage signal VBV3 having a voltage value of voltage Vb3, and a waveform selection control circuit 210 controls the output switching circuits 252-1 to 252-7 based on a print data signal SI.

[0123] The drive signal output circuit 200 outputs a drive signal VOUT that corresponds to a signal of a constant current value based on the drive voltage signal VHV3 output by the output switching circuit 252-1, a signal of a constant current value based on the drive voltage signal VHV2 output by the output switching circuit 252-2, a signal of a constant current value based on the drive voltage signal VHV1 output by the output switching circuit 252-3, a signal of a constant current value based on the drive voltage signal VCV output by the output switching circuit 252-4, a signal of a constant current value based on the drive voltage signal VBV1 output by the output switching circuit 252-5, a signal of a constant current value based on the drive voltage signal VBV2 output by the output switching circuit 252-6, and a signal of a constant current value based on the drive voltage signal VBV3 output by the output switching circuit 252-7.

[0124] That is, the drive signal output circuit 200 generates a drive signal VOUT whose voltage value changes between voltages Vh3, Vh2, Vh1, Vc, Vb1, Vh2, and Vb3 by each of the output switching circuits 252-1 to 252-7 selecting each of the drive voltage signals VHV3, VHV2, VHV1, VCV, VBV1, VBV2, and VHV3, and outputs it to the ejection portion 600. As a result, the liquid ejection device 1 and the head unit 20 do not need to use an amplifier circuit such as a class D amplifier or a class AB amplifier for driving the piezoelectric element 60, and the head unit 20 and the liquid ejection device 1 can be made smaller in size.

[0125] In the liquid ejection device 1 and head unit 20 of the first embodiment, each of the output switching circuits 252-1 to 252-7 selects each of the ejection section 600 drive voltage signals VHV3, VHV2, VHV1, VCV, VBV1, VBV2, and VHV3, and the drive signal output circuit 200 outputs the drive signal VOUT whose voltage value changes between voltages Vh3, Vh2, Vh1, Vc, Vb1, Vh2, and Vb3 to each of the ejection sections 600[1] to 600[n]. Therefore, in the liquid ejection device 1 and head unit 20 of the first embodiment, there is no need to use an amplifier circuit such as a class D amplifier that performs switching operation or a class AB amplifier through which a large current flows, and the loss of the liquid ejection device 1 and head unit 20 is reduced. As a result, the power consumption in the liquid ejection device 1 and head unit 20 is reduced.

[0126] The reduction in power consumption in the drive signal output circuit 200 reduces the heat generated by the drive signal output circuit 200. This reduces the risk that the characteristics of the ink stored in the print head 21 will change due to the influence of heat generated by the drive signal output circuit 200. Therefore, in the liquid ejection device 1 and the head unit 20 of the first embodiment, the drive signal output circuit 200 that outputs the drive signal VOUT can be disposed in the vicinity of the ejection section 600 on the flexible wiring board 400 that propagates various signals to the ejection section 600. As a result, it is possible to shorten the propagation distance over which the drive signal VOUT propagates between the drive signal output circuit 200 and the ejection section 600, and the risk that the signal waveform of the drive signal VOUT will be distorted due to the influence of the impedance of the propagation path over which the drive signal VOUT propagates is reduced. Therefore, the waveform accuracy of the drive signal VOUT supplied to the ejection section 600 is improved, and the ejection accuracy of the ink ejected from the ejection section 600 is improved.

[0127] In addition, since the drive signal output circuit 200 that outputs the drive signal VOUT can be disposed near the ejection unit 600 such as the flexible wiring board 400, the difference between the propagation distance of the drive signal VOUT[1] output by the drive signal output circuit 200 to the ejection unit 600[1] and the propagation distance of the drive signal VOUT[2] output by the drive signal output circuit 200 to the ejection unit 600[2] is reduced, and the propagation distances can be made substantially equal. This reduces the risk of signal delay occurring between the drive signal VOUT[1] supplied to the ejection unit 600[1] and the drive signal VOUT[2] supplied to the ejection unit 600[2]. As a result, the ejection accuracy of ink from the print head 21 including the ejection units 600[1] and 600[2] is improved.

[0128] Furthermore, in the liquid ejection device 1 and the head unit 20 of the first embodiment, the drive signal output circuit 200 outputs a drive signal VOUT corresponding to a signal of a constant current value based on the drive voltage signal VHV3 output by the output switching circuit 252-1, a signal of a constant current value based on the drive voltage signal VHV2 output by the output switching circuit 252-2, a signal of a constant current value based on the drive voltage signal VHV1 output by the output switching circuit 252-3, a signal of a constant current value based on the drive voltage signal VCV output by the output switching circuit 252-4, a signal of a constant current value based on the drive voltage signal VBV1 output by the output switching circuit 252-5, a signal of a constant current value based on the drive voltage signal VBV2 output by the output switching circuit 252-6, and a signal of a constant current value based on the drive voltage signal VBV3 output by the output switching circuit 252-7. That is, the drive signal VOUT controlled to a constant current value is supplied to the piezoelectric element 60, which is a capacitive load. This reduces the risk that distortion will occur in the signal waveform of the drive signal VOUT due to the capacitive component of the piezoelectric element 60 when the voltage value of the drive signal VOUT changes. This improves the waveform accuracy of the drive signal VOUT supplied to the ejection unit 600, and improves the ejection accuracy of the ink ejected from the ejection unit 600.

[0129] 1.6 Variations In the first embodiment of the liquid ejection device 1 described above, the output switching circuit 252-1 of the output circuit 250 has been described as having one pair of a switch sw1a and a constant current circuit ci1 that outputs a signal of a constant current value based on the voltage Vh3, which is the voltage value of the drive voltage signal VHV3, and the voltage value of the drive signal VOUT to the ejection section 600. However, the output switching circuit 252-1 may have multiple pairs of a switch sw1a and a constant current circuit ci1 that outputs a signal of a constant current value based on the voltage Vh3 and the voltage value of the drive signal VOUT to the ejection section 600.

[0130] Similarly, the output switching circuit 252-2 may have a plurality of pairs of a switch sw2a and a constant current circuit ci2 that output a signal of a constant current value based on the voltage Vh2 that is the voltage value of the drive voltage signal VHV2 and the voltage value of the drive signal VOUT to the discharge unit 600, the output switching circuit 252-3 may have a plurality of pairs of a switch sw3a and a constant current circuit ci3 that output a signal of a constant current value based on the voltage Vh1 that is the voltage value of the drive voltage signal VHV1 and the voltage value of the drive signal VOUT to the discharge unit 600, and the output switching circuit 252-4 may have a plurality of pairs of a switch sw3a and a constant current circuit ci3 that output a signal of a constant current value based on the voltage Vc that is the voltage value of the drive voltage signal VCV and the voltage value of the drive signal VOUT to the discharge unit 600. The output switching circuit 252-5 may have multiple pairs of a switch sw5a and a constant current circuit ci5 that output a constant current signal based on the voltage Vb1, which is the voltage value of the drive voltage signal VBV1, and the voltage value of the drive signal VOUT, to the discharge section 600, and the output switching circuit 252-6 may have multiple pairs of a switch sw6a and a constant current circuit ci6 that output a constant current signal based on the voltage Vb2, which is the voltage value of the drive voltage signal VBV2, and the voltage value of the drive signal VOUT, to the discharge section 600.

[0131] Furthermore, in the first embodiment of the liquid ejection device 1 described above, the output switching circuit 252-2 of the output circuit 250 has been described as having one pair of a switch sw2b and a constant current circuit co2 that draws in from the ejection section 600 a signal of a constant current value based on the voltage Vh2, which is the voltage value of the drive voltage signal VHV2, and the voltage value of the drive signal VOUT, but the output switching circuit 252-2 may have multiple pairs of a switch sw2b and a constant current circuit co2 that draw in from the ejection section 600 a current based on the voltage Vh2 and the voltage value of the drive signal VOUT.

[0132] Similarly, the output switching circuit 252-3 may have a plurality of pairs of a switch sw3b and a constant current circuit co3 that draw in from the discharge unit 600 a signal of a constant current value based on the voltage Vh1 that is the voltage value of the drive voltage signal VHV1 and the voltage value of the drive signal VOUT, the output switching circuit 252-4 may have a plurality of pairs of a switch sw4b and a constant current circuit co4 that draw in from the discharge unit 600 a signal of a constant current value based on the voltage Vc that is the voltage value of the drive voltage signal VCV and the voltage value of the drive signal VOUT, and the output switching circuit 252-5 may have a plurality of pairs of a switch sw4b and a constant current circuit co4 that draw in from the discharge unit 600 a signal of a constant current value based on the voltage Vb1 that is the voltage value of the drive voltage signal VBV1 and the voltage value of the drive signal VOUT. The output switching circuit 252-6 may have a plurality of pairs of a switch sw6b and a constant current circuit co6 that draw in, from the output unit 600, a signal of a constant current value based on the voltage Vb2 that is the voltage value of the drive voltage signal VBV2 and the voltage value of the drive signal VOUT, and the output switching circuit 252-7 may have a plurality of pairs of a switch sw7b and a constant current circuit co7 that draw in, from the output unit 600, a signal of a constant current value based on the voltage Vb3 that is the voltage value of the drive voltage signal VBV3 and the voltage value of the drive signal VOUT.

[0133] A specific example of the configuration of the liquid ejection device 1 of the modified example will be described. Fig. 14 is a diagram showing an example of the configuration of an output switching circuit 252-1 of the modified example. As shown in Fig. 14, the output switching circuit 252-1 of the modified example includes switches sw1a-1 to sw1a-4 and constant current circuits ci1-1 to ci1-4. Furthermore, voltage selection signals S1-1, S1-2, S1-3, and S1-4 as the voltage selection signal S1, and a drive voltage signal VHV3 are input to the output switching circuit 252-1 of the modified example.

[0134] The voltage selection signal S1-1 is input to the control terminal of the switch sw1a-1. The voltage selection signal S1-2 is input to the control terminal of the switch sw1a-2. The voltage selection signal S1-3 is input to the control terminal of the switch sw1a-3. The voltage selection signal S1-4 is input to the control terminal of the switch sw1a-4. The drive voltage signal VHV3 is input to one terminal of the switches sw1a-1 to sw1a-4. The other terminal of the switch sw1a-1 is electrically connected to the input terminal of the constant current circuit ci1-1. The other terminal of the switch sw1a-2 is electrically connected to the input terminal of the constant current circuit ci1-2. The other terminal of the switch sw1a-3 is electrically connected to the input terminal of the constant current circuit ci1-3. The other terminal of the switch sw1a-4 is electrically connected to the input terminal of the constant current circuit ci1-4.

[0135] In the output switching circuit 252-1 of the modified example configured as above, when an H-level voltage selection signal S1-1 is input to the control terminal of the switch sw1a-1, one terminal and the other terminal of the switch sw1a-1 are controlled to be conductive. As a result, a drive voltage signal VHV3 is supplied to the input terminal of the constant current circuit ci1-1, and the constant current circuit ci1-1 outputs a signal of a constant current value based on the voltage Vh3 supplied to the input terminal and the voltage value of the output terminal from the output terminal.

[0136] When an H-level voltage selection signal S1-2 is input to the control terminal of the switch sw1a-2, one terminal and the other terminal of the switch sw1a-2 are controlled to be conductive. As a result, a drive voltage signal VHV3 is supplied to the input terminal of the constant current circuit ci1-2, and the constant current circuit ci1-2 outputs a signal of a constant current value based on the voltage Vh3 supplied to the input terminal and the voltage value of the output terminal from the output terminal.

[0137] When an H-level voltage selection signal S1-3 is input to the control terminal of the switch sw1a-3, one terminal and the other terminal of the switch sw1a-3 are controlled to be conductive, whereby a drive voltage signal VHV3 is supplied to the input terminal of the constant current circuit ci1-3, and the constant current circuit ci1-3 outputs a signal of a constant current value based on the voltage Vh3 supplied to the input terminal and the voltage value of the output terminal from the output terminal.

[0138] When an H-level voltage selection signal S1-4 is input to the control terminal of the switch sw1a-4, one terminal and the other terminal of the switch sw1a-4 are controlled to be conductive. As a result, the drive voltage signal VHV3 is supplied to the input terminal of the constant current circuit ci1-4, and the constant current circuit ci1-4 outputs a signal of a constant current value based on the voltage Vh3 supplied to the input terminal and the voltage value of the output terminal from the output terminal.

[0139] That is, in the output switching circuit 252-1 of the modified example, a set of a switch sw1a-1 and a constant current circuit ci1-1, a set of a switch sw1a-2 and a constant current circuit ci1-2, a set of a switch sw1a-3 and a constant current circuit ci1-3, and a set of a switch sw1a-4 and a constant current circuit ci1-4 are connected in parallel between a wiring pattern to which the drive voltage signal VHV3 is supplied and a wiring pattern to which the drive signal VOUT is output. Then, by individually switching the conductive state of the switches sw1a-1 to sw1a-4 based on the logical levels of the voltage selection signals S1-1 to S1-4, the output switching circuit 252-1 of the modified example can be switched to output or not output a signal of a constant current value based on the voltage Vh3 and the voltage value of the output terminal.

[0140] In the following description, the voltage selection signal S1-1 input to the control end of the switch sw1a-1, the voltage selection signal S1-2 input to the control end of the switch sw1a-2, the voltage selection signal S1-3 input to the control end of the switch sw1a-3, and the voltage selection signal S1-4 input to the control end of the switch sw1a-4 may be collectively referred to as voltage selection signal S1[S1-1, S1-2, S1-3, S1-4].

[0141] When the voltage selection signal S1 [S1-1, S1-2, S1-3, S1-4] = [H, L, L, L] is input to the output switching circuit 252-1 of the modified example configured as above, the switch sw1a-1 is controlled so that one end and the other end are conductive, and the switches sw1a-2 to sw1a-4 are controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-1 outputs a constant signal to the discharge unit 600 at a current value determined by the constant current circuit ci1-1 based on the voltage Vh3 and the voltage value of the output terminal.

[0142] In addition, when the voltage selection signal S1 [S1-1, S1-2, S1-3, S1-4] = [H, H, L, L] is input to the output switching circuit 252-1 of the modified example, the switches sw1a-1 and sw1a-2 are controlled so that one end and the other end are conductive, and the switches sw1a-3 and sw1a-4 are controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-1 outputs a constant signal to the discharge unit 600 with a current value that is the sum of the current value determined by the constant current circuit ci1-1 and the current value determined by the constant current circuit ci1-2 based on the voltage Vh3 and the voltage value of the output terminal.

[0143] In addition, when the voltage selection signal S1 [S1-1, S1-2, S1-3, S1-4] = [H, H, H, L] is input to the output switching circuit 252-1 of the modified example, the switches sw1a-1 to sw1a-3 are controlled so that one end and the other end are conductive, and the switch sw1a-4 is controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-1 outputs a constant signal to the discharge unit 600 with a current value that is the sum of a current value determined by the constant current circuit ci1-1, a current value determined by the constant current circuit ci1-2, and a current value determined by the constant current circuit ci1-3 based on the voltage Vh3 and the voltage value of the output terminal.

[0144] In addition, when the voltage selection signal S1 [S1-1, S1-2, S1-3, S1-4] = [H, H, H, H] is input to the output switching circuit 252-1 of the modified example, the switches sw1a-1 to sw1a-4 are controlled so that one end and the other end are conductive. At this time, the output switching circuit 252-1 outputs a constant signal to the discharge unit 600 at a current value that is the sum of a current value determined by the constant current circuit ci1-1, a current value determined by the constant current circuit ci1-2, a current value determined by the constant current circuit ci1-3, and a current value determined by the constant current circuit ci1-4, based on the voltage Vh3 and the voltage value of the output terminal.

[0145] As a result, the output switching circuit 252-1 of the modified example can control the current value output to the discharge unit 600 according to the logic level of the voltage selection signal S1 [S1-1, S1-2, S1-3, S1-4] as the voltage selection signal S output by the waveform selection control circuit 210. Here, the switch sw1a-1 and the constant current circuit ci1-1 may be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch sw1a-2 and the constant current circuit ci1-2, the switch sw1a-3 and the constant current circuit ci1-3, and the switch sw1a-4 and the constant current circuit ci1-4 may each be configured with separate circuit elements or may be configured with one circuit element.

[0146] That is, the output switching circuit 252-1 of the modified example has a constant current circuit ci1-1 having one end supplied with the drive voltage signal VHV3 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV3, a constant current circuit ci1-2 having one end supplied with the drive voltage signal VHV3 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV3, a constant current circuit ci1-3 having one end supplied with the drive voltage signal VHV3 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV3, and a constant current circuit ci1-4 having one end supplied with the drive voltage signal VHV3 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV3. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit ci1-1 outputs a signal of a constant current value based on the drive voltage signal VHV3, whether the constant current circuit ci1-2 outputs a signal of a constant current value based on the drive voltage signal VHV3, whether the constant current circuit ci1-3 outputs a signal of a constant current value based on the drive voltage signal VHV3, and whether the constant current circuit ci1-4 outputs a signal of a constant current value based on the drive voltage signal VHV3, thereby controlling the current value output from the output switching circuit 252-1 of the modified example.

[0147] Fig. 15 is a diagram showing an example of the configuration of an output switching circuit 252-2 of a modified example. As shown in Fig. 15, the output switching circuit 252-2 of the modified example includes switches sw2a-1 to sw2a-4, sw2b-1 to sw2b-4, and constant current circuits ci2-1 to ci2-4, co2-1 to co2-4. In addition, the output switching circuit 252-2 receives voltage selection signals S2a-1, S2a-2, S2a-3, and S2a-4 as the voltage selection signal S2a, voltage selection signals S2b-1, S2b-2, S2b-3, and S2b-4 as the voltage selection signal S2b, and a drive voltage signal VHV2.

[0148] The voltage selection signal S2a-1 is input to a control end of the switch sw2a-1. The voltage selection signal S2a-2 is input to a control end of the switch sw2a-2. The voltage selection signal S2a-3 is input to a control end of the switch sw2a-3. The voltage selection signal S2a-4 is input to a control end of the switch sw2a-4. The voltage selection signal S2b-1 is input to a control end of the switch sw2b-1. The voltage selection signal S2b-2 is input to a control end of the switch sw2b-2. The voltage selection signal S2b-3 is input to a control end of the switch sw2b-3. The voltage selection signal S2b-4 is input to a control end of the switch sw2b-4. The drive voltage signal VHV2 is input to one end of the switches sw2a-1 to sw2a-4, sw2b-1 to sw2b-4. The other end of the switch SW2A-1 is electrically connected to the input terminal of the constant current circuit CI2-1. The other end of the switch SW2A-2 is electrically connected to the input terminal of the constant current circuit CI2-2. The other end of the switch SW2A-3 is electrically connected to the input terminal of the constant current circuit CI2-3. The other end of the switch SW2A-4 is electrically connected to the input terminal of the constant current circuit CI2-4. The other end of the switch SW2B-1 is electrically connected to the output terminal of the constant current circuit CO2-1. The other end of the switch SW2B-2 is electrically connected to the output terminal of the constant current circuit CO2-2. The other end of the switch SW2B-3 is electrically connected to the output terminal of the constant current circuit CO2-3. The other end of the switch SW2B-4 is electrically connected to the output terminal of the constant current circuit CO2-4.

[0149] In the output switching circuit 252-2 of the modified example configured as above, when an H-level voltage selection signal S2a-1 is input to the control terminal of the switch sw2a-1, the switch sw2a-1 is controlled so that one terminal and the other terminal are conductive. As a result, the drive voltage signal VHV2 is supplied to the input terminal of the constant current circuit ci2-1, and the constant current circuit ci2-1 outputs a signal of a constant current value from the output terminal based on the voltage Vh2 supplied to the input terminal and the voltage value of the output terminal.

[0150] When an H-level voltage selection signal S2a-2 is input to the control terminal of the switch sw2a-2, one terminal and the other terminal of the switch sw2a-2 are controlled to be conductive. As a result, a drive voltage signal VHV2 is supplied to the input terminal of the constant current circuit ci2-2, and the constant current circuit ci2-2 outputs a signal of a constant current value based on the voltage Vh2 supplied to the input terminal and the voltage value of the output terminal from the output terminal.

[0151] When an H-level voltage selection signal S2a-3 is input to the control terminal of the switch sw2a-3, one terminal and the other terminal of the switch sw2a-3 are controlled to be conductive. As a result, the drive voltage signal VHV2 is supplied to the input terminal of the constant current circuit ci2-3, and the constant current circuit ci2-3 outputs a signal of a constant current value based on the voltage Vh2 supplied to the input terminal and the voltage value of the output terminal from the output terminal.

[0152] When an H-level voltage selection signal S2a-4 is input to the control terminal of the switch sw2a-4, one terminal and the other terminal of the switch sw2a-4 are controlled to be conductive. As a result, the drive voltage signal VHV2 is supplied to the input terminal of the constant current circuit ci2-4, and the constant current circuit ci2-4 outputs a signal of a constant current value based on the voltage Vh2 supplied to the input terminal and the voltage value of the output terminal from the output terminal.

[0153] When an H-level voltage selection signal S2b-1 is input to the control terminal of the switch sw2b-1, one terminal and the other terminal of the switch sw2b-1 are controlled to be conductive, whereby a drive voltage signal VHV2 is supplied to the output terminal of the constant current circuit co2-1, and the constant current circuit ci2-1 outputs a signal of a constant current value from its output terminal based on the voltage value of the input terminal and the voltage Vh2 supplied to the output terminal.

[0154] When an H-level voltage selection signal S2b-2 is input to the control terminal of the switch sw2b-2, one terminal and the other terminal of the switch sw2b-2 are controlled to be conductive, whereby a drive voltage signal VHV2 is supplied to the output terminal of the constant current circuit ci2-2, and the constant current circuit ci2-2 outputs a signal of a constant current value from its output terminal based on the voltage value of the input terminal and the voltage Vh2 supplied to the output terminal.

[0155] When an H-level voltage selection signal S2b-3 is input to the control terminal of the switch sw2b-3, one terminal and the other terminal of the switch sw2a-3 are controlled to be conductive, whereby the drive voltage signal VHV2 is supplied to the output terminal of the constant current circuit ci2-3, and the constant current circuit ci2-3 outputs a signal of a constant current value based on the voltage value of the input terminal and the voltage Vh2 supplied to the output terminal from the output terminal.

[0156] When an H-level voltage selection signal S2b-4 is input to the control terminal of the switch sw2b-4, the switch sw2a-4 is controlled so that one terminal and the other terminal are conductive, whereby the drive voltage signal VHV2 is supplied to the output terminal of the constant current circuit ci2-4, and the constant current circuit ci2-4 outputs a signal of a constant current value from the output terminal based on the voltage value of the input terminal and the voltage Vh2 supplied to the output terminal.

[0157] That is, in the output switching circuit 252-2 of the modified example, a pair of switch sw2a-1 and constant current circuit ci2-1, a pair of switch sw2a-2 and constant current circuit ci2-2, a pair of switch sw2a-3 and constant current circuit ci2-3, a pair of switch sw2a-4 and constant current circuit ci2-4, a pair of switch sw2b-1 and constant current circuit co2-1, a pair of switch sw2b-2 and constant current circuit co2-2, a pair of switch sw2b-3 and constant current circuit co2-3, and a pair of switch sw2b-4 and constant current circuit co2-4 are connected in parallel between the wiring pattern to which the drive voltage signal VHV2 is supplied and the wiring pattern to which the drive signal VOUT is output.

[0158] The conductive state of the switches sw2a-1 to sw2a-4 can be individually switched based on the logical levels of the voltage selection signals S2a-1 to S2a-4, so that the output switching circuit 252-2 of the modified example switches whether or not to output a signal of a constant current value based on the voltage Vh2 and the voltage value of the output terminal, and the conductive state of the switches sw2b-1 to sw2b-4 can be individually switched based on the logical levels of the voltage selection signals S2b-1 to S2b-4, so that the output switching circuit 252-2 of the modified example switches whether or not to draw in a signal of a constant current value based on the voltage value of the input terminal and voltage Vh2.

[0159] Here, in the following description, the voltage selection signal S2a-1 input to the control end of switch sw2a-1, the voltage selection signal S2a-2 input to the control end of switch sw2a-2, the voltage selection signal S2a-3 input to the control end of switch sw2a-3, and the voltage selection signal S2a-4 input to the control end of switch sw2a-4 may be collectively referred to as voltage selection signal S2a [S2a-1, S2a-2, S2a-3, S2a-4]. Similarly, the voltage selection signal S2b-1 input to the control end of switch sw2b-1, the voltage selection signal S2b-2 input to the control end of switch sw2b-2, the voltage selection signal S2b-3 input to the control end of switch sw2b-3, and the voltage selection signal S2b-4 input to the control end of switch sw2b-4 may be collectively referred to as voltage selection signals S2b [S2b-1, S2b-2, S2b-3, S2b-4].

[0160] When the voltage selection signal S2a [S2a-1, S2a-2, S2a-3, S2a-4] = [H, L, L, L] is input to the output switching circuit 252-2 of the modified example configured as above, the switch sw2a-1 is controlled so that one end and the other end are conductive, and the switches sw2a-2 to sw2a-4 are controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-2 outputs a constant signal to the discharge unit 600 at a current value determined by the constant current circuit ci2-1 based on the voltage Vh2 and the voltage value of the output terminal.

[0161] In addition, when the voltage selection signal S2a [S2a-1, S2a-2, S2a-3, S2a-4] = [H, H, L, L] is input to the output switching circuit 252-2 of the modified example, the switches sw2a-1 and sw2a-2 are controlled so that one end and the other end are conductive, and the switches sw2a-3 and sw2a-4 are controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-2 outputs a constant signal to the discharge unit 600 at a current value that is the sum of a current value determined by the constant current circuit ci2-1 and a current value determined by the constant current circuit ci2-2 based on the voltage Vh2 and the voltage value of the output terminal.

[0162] In addition, when the voltage selection signal S2a [S2a-1, S2a-2, S2a-3, S2a-4] = [H, H, H, L] is input to the output switching circuit 252-2 of the modified example, the switches sw2a-1 to sw2a-3 are controlled so that one end and the other end are conductive, and the switch sw2a-4 is controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-2 outputs a constant signal to the discharge unit 600 with a current value that is the sum of a current value determined by the constant current circuit ci2-1, a current value determined by the constant current circuit ci2-2, and a current value determined by the constant current circuit ci2-3 based on the voltage Vh2 and the voltage value of the output terminal.

[0163] In addition, when the voltage selection signal S2a [S2a-1, S2a-2, S2a-3, S2a-4] = [H, H, H, H] is input to the output switching circuit 252-2 of the modified example, the switches sw2a-1 to sw2a-4 are controlled so that one end and the other end are conductive. At this time, the output switching circuit 252-2 outputs a constant signal to the discharge unit 600 at a current value that is the sum of a current value determined by the constant current circuit ci2-1, a current value determined by the constant current circuit ci2-2, a current value determined by the constant current circuit ci2-3, and a current value determined by the constant current circuit ci2-4 based on the voltage Vh2 and the voltage value of the output terminal.

[0164] In addition, when the voltage selection signal S2b [S2b-1, S2b-2, S2b-3, S2b-4] = [H, L, L, L] is input to the output switching circuit 252-2 of the modified example, the switch sw2b-1 is controlled so that one end and the other end are conductive, and the switches sw2b-2 to sw2b-4 are controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-2 draws a constant signal from the discharge unit 600 at a current value determined by the constant current circuit co2-1 based on the voltage value of the input terminal and the voltage Vh2.

[0165] In addition, when the voltage selection signal S2b [S2b-1, S2b-2, S2b-3, S2b-4] = [H, H, L, L] is input to the output switching circuit 252-2 of the modified example, the switches sw2b-1 and sw2b-2 are controlled so that one end and the other end are conductive, and the switches sw2b-3 and sw2b-4 are controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-2 draws a constant signal from the discharge unit 600 with a current value that is the sum of the current value determined by the constant current circuit co2-1 and the current value determined by the constant current circuit co2-2 based on the voltage value of the input terminal and the voltage Vh2.

[0166] In addition, when the voltage selection signal S2b [S2b-1, S2b-2, S2b-3, S2b-4] = [H, H, H, L] is input to the output switching circuit 252-2 of the modified example, the switches sw2b-1 to sw2b-3 are controlled so that one end and the other end are conductive, and the switch sw2b-4 is controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-2 draws a constant signal from the discharge unit 600 with a current value that is the sum of the current value determined by the constant current circuit co2-1, the current value determined by the constant current circuit co2-2, and the current value determined by the constant current circuit co2-3 based on the voltage value of the input terminal and the voltage Vh2.

[0167] In addition, when the voltage selection signal S2b [S2b-1, S2b-2, S2b-3, S2b-4] = [H, H, H, H] is input to the output switching circuit 252-2 of the modified example, the switches sw2b-1 to sw2b-4 are controlled so that one end and the other end are conductive. At this time, the output switching circuit 252-2 draws a constant signal from the discharge unit 600 with a current value that is the sum of the current value determined by the constant current circuit co2-1, the current value determined by the constant current circuit co2-2, the current value determined by the constant current circuit co2-3, and the current value determined by the constant current circuit co2-4 based on the voltage value of the input end and the voltage Vh2.

[0168] As a result, the output switching circuit 252-2 of the modified example can control the current value output to the discharge unit 600 according to the logic level of the voltage selection signal S2a [S2a-1, S2a-2, S2a-3, S2a-4] as the voltage selection signal S output by the waveform selection control circuit 210, and can control the current value drawn from the discharge unit 600 according to the logic level of the voltage selection signal S2b [S2b-1, S2b-2, S2b-3, S2b-4] as the voltage selection signal S output by the waveform selection control circuit 210. Here, the switch sw2a-1 and the constant current circuit ci2-1 may be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch sw2a-2 and the constant current circuit ci2-2, the switch sw2a-3 and the constant current circuit ci2-3, and the switch sw2a-4 and the constant current circuit ci2-4 may each be configured with separate circuit elements or may be configured with one circuit element. In addition, the switch SW2b-1 and the constant current circuit CO2-1 may be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch SW2b-2 and the constant current circuit CO2-2, the switch SW2b-3 and the constant current circuit CO2-3, and the switch SW2b-4 and the constant current circuit CO2-4 may each be configured with separate circuit elements or may be configured with one circuit element.

[0169] That is, the output switching circuit 252-2 of the modified example has a constant current circuit ci2-1 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV2, a constant current circuit ci2-2 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV2, a constant current circuit ci2-3 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV2, and a constant current circuit ci2-4 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV2. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit ci2-1 outputs a signal of a constant current value based on the drive voltage signal VHV2, whether the constant current circuit ci2-2 outputs a signal of a constant current value based on the drive voltage signal VHV2, whether the constant current circuit ci2-3 outputs a signal of a constant current value based on the drive voltage signal VHV2, and whether the constant current circuit ci2-4 outputs a signal of a constant current value based on the drive voltage signal VHV2, thereby controlling the current value output from the output switching circuit 252-2 of the modified example.

[0170] In addition, the output switching circuit 252-2 of the modified example has a constant current circuit co2-1 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV2, a constant current circuit co2-2 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV2, a constant current circuit co2-3 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV2, and a constant current circuit co2-4 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV2. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit co2-1 outputs a signal of a constant current value based on the drive voltage signal VHV2, whether the constant current circuit co2-2 outputs a signal of a constant current value based on the drive voltage signal VHV2, whether the constant current circuit co2-3 outputs a signal of a constant current value based on the drive voltage signal VHV2, and whether the constant current circuit co2-4 outputs a signal of a constant current value based on the drive voltage signal VHV2, thereby controlling the current value drawn by the output switching circuit 252-2 of the modified example.

[0171] Here, the output switching circuits 252-3 to 252-6 of the modified example have the same configuration as the output switching circuit 252-2 of the modified example, except that the input signals and output signals are different. Therefore, the configurations of the output switching circuits 252-3 to 252-6 of the modified example are not shown in the figures, and the description will be simplified.

[0172] The output switching circuit 252-3 of the modified example has a pair of a switch sw3a-1 and a constant current circuit ci3-1, a pair of a switch sw3a-2 and a constant current circuit ci3-2, a pair of a switch sw3a-3 and a constant current circuit ci3-3, a pair of a switch sw3a-4 and a constant current circuit ci3-4, a pair of a switch sw3b-1 and a constant current circuit co3-1, a pair of a switch sw3b-2 and a constant current circuit co3-2, a pair of a switch sw3b-3 and a constant current circuit co3-3, and a pair of a switch sw3b-4 and a constant current circuit co3-4, all connected in parallel between a wiring pattern to which a drive voltage signal VHV1 is supplied and a wiring pattern to which a drive signal VOUT is output.

[0173] Each of the pair of switch sw3a-1 and constant current circuit ci3-1, the pair of switch sw3a-2 and constant current circuit ci3-2, the pair of switch sw3a-3 and constant current circuit ci3-3, and the pair of switch sw3a-4 and constant current circuit ci3-4 switches whether or not to output a signal of a constant current value based on the voltage Vh1 and the voltage value of the output terminal from the output switching circuit 252-3 based on the logical level of the voltage selection signal S3a [S3a-1, S3a-2, S3a-3, S3a-4] as the voltage selection signal S. Similarly, the pair of switch sw3b-1 and constant current circuit co3-1, the pair of switch sw3b-2 and constant current circuit co3-2, the pair of switch sw3b-3 and constant current circuit co3-3, and the pair of switch sw3b-4 and constant current circuit co3-4 each switch whether or not to draw a signal of a constant current value based on the voltage value of the input terminal and voltage Vh1 into the output switching circuit 252-3 based on the logical level of the voltage selection signal S3b [S3b-1, S3b-2, S3b-3, S3b-4] as the voltage selection signal S.

[0174] Therefore, the output switching circuit 252-3 of the modified example can control the current value output to the discharge portion 600 according to the logical level of the voltage selection signal S3a [S3a-1, S3a-2, S3a-3, S3a-4] as the voltage selection signal S output by the waveform selection control circuit 210, and can control the current value drawn from the discharge portion 600 according to the logical level of the voltage selection signal S3b [S3b-1, S3b-2, S3b-3, S3b-4] as the voltage selection signal S output by the waveform selection control circuit 210.

[0175] That is, the output switching circuit 252-3 of the modified example has a constant current circuit ci3-1 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV1, a constant current circuit ci3-2 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV1, a constant current circuit ci3-3 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV1, and a constant current circuit ci3-4 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV1. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit ci3-1 outputs a signal of a constant current value based on the drive voltage signal VHV1, whether the constant current circuit ci3-2 outputs a signal of a constant current value based on the drive voltage signal VHV1, whether the constant current circuit ci3-3 outputs a signal of a constant current value based on the drive voltage signal VHV1, and whether the constant current circuit ci3-4 outputs a signal of a constant current value based on the drive voltage signal VHV1, thereby controlling the current value output from the output switching circuit 252-3 of the modified example.

[0176] In addition, the output switching circuit 252-3 of the modified example has a constant current circuit co3-1 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV1, a constant current circuit co3-2 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV1, a constant current circuit co3-3 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV1, and a constant current circuit co3-4 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VHV1. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit co3-1 outputs a signal of a constant current value based on the drive voltage signal VHV1, whether the constant current circuit co3-2 outputs a signal of a constant current value based on the drive voltage signal VHV1, whether the constant current circuit co3-3 outputs a signal of a constant current value based on the drive voltage signal VHV1, and whether the constant current circuit co3-4 outputs a signal of a constant current value based on the drive voltage signal VHV1, thereby controlling the current value drawn by the output switching circuit 252-3 of the modified example.

[0177] Here, the switch SW3a-1 and the constant current circuit CI3-1 may be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch SW3a-2 and the constant current circuit CI3-2, the switch SW3a-3 and the constant current circuit CI3-3, and the switch SW3a-4 and the constant current circuit CI3-4 may each be configured with separate circuit elements or may be configured with one circuit element. Also, the switch SW3b-1 and the constant current circuit CO3-1 may each be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch SW3b-2 and the constant current circuit CO3-2, the switch SW3b-3 and the constant current circuit CO3-3, and the switch SW3b-4 and the constant current circuit CO3-4 may each be configured with separate circuit elements or may be configured with one circuit element.

[0178] In addition, the output switching circuit 252-4 of the modified example has a pair of a switch sw4a-1 and a constant current circuit ci4-1, a pair of a switch sw4a-2 and a constant current circuit ci4-2, a pair of a switch sw4a-3 and a constant current circuit ci4-3, a pair of a switch sw4a-4 and a constant current circuit ci4-4, a pair of a switch sw4b-1 and a constant current circuit co4-1, a pair of a switch sw4b-2 and a constant current circuit co4-2, a pair of a switch sw4b-3 and a constant current circuit co4-3, and a pair of a switch sw4b-4 and a constant current circuit co4-4, which are connected in parallel between the wiring pattern to which the drive voltage signal VCV is supplied and the wiring pattern to which the drive signal VOUT is output.

[0179] Each of the pair of switch sw4a-1 and constant current circuit ci4-1, the pair of switch sw4a-2 and constant current circuit ci4-2, the pair of switch sw4a-3 and constant current circuit ci4-3, and the pair of switch sw4a-4 and constant current circuit ci4-4 switches whether or not to output a signal of a constant current value based on the voltage Vc and the voltage value of the output terminal from the output switching circuit 252-4 based on the logical level of the voltage selection signal S4a [S4a-1, S4a-2, S4a-3, S4a-4] as the voltage selection signal S. Similarly, the pair of switch sw4b-1 and constant current circuit co4-1, the pair of switch sw4b-2 and constant current circuit co4-2, the pair of switch sw4b-3 and constant current circuit co4-3, and the pair of switch sw4b-4 and constant current circuit co4-4 switch whether or not to draw a signal of a constant current value based on the voltage value of the input terminal and voltage Vc into the output switching circuit 252-4 based on the logical level of the voltage selection signal S4b [S4b-1, S4b-2, S4b-3, S4b-4] as the voltage selection signal S.

[0180] Therefore, the output switching circuit 252-4 of the modified example can control the current value output to the discharge portion 600 according to the logical level of the voltage selection signal S4a [S4a-1, S4a-2, S4a-3, S4a-4] as the voltage selection signal S output by the waveform selection control circuit 210, and can control the current value drawn from the discharge portion 600 according to the logical level of the voltage selection signal S4b [S4b-1, S4b-2, S4b-3, S4b-4] as the voltage selection signal S output by the waveform selection control circuit 210.

[0181] That is, the output switching circuit 252-4 of the modified example has a constant current circuit ci4-1, which has one end supplied with the drive voltage signal VCV and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputs a signal of a constant current value based on the drive voltage signal VCV, a constant current circuit ci4-2, which has one end supplied with the drive voltage signal VCV and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputs a signal of a constant current value based on the drive voltage signal VCV, a constant current circuit ci4-3, which has one end supplied with the drive voltage signal VCV and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputs a signal of a constant current value based on the drive voltage signal VCV, and a constant current circuit ci4-4, which has one end supplied with the drive voltage signal VCV and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputs a signal of a constant current value based on the drive voltage signal VCV. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit ci4-1 outputs a signal of a constant current value based on the drive voltage signal VCV, whether the constant current circuit ci4-2 outputs a signal of a constant current value based on the drive voltage signal VCV, whether the constant current circuit ci4-3 outputs a signal of a constant current value based on the drive voltage signal VCV, and whether the constant current circuit ci4-4 outputs a signal of a constant current value based on the drive voltage signal VCV, thereby controlling the current value output from the output switching circuit 252-4 of the modified example.

[0182] In addition, the output switching circuit 252-4 of the modified example has a constant current circuit co4-1 having one end supplied with the drive voltage signal VCV and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VCV, a constant current circuit co4-2 having one end supplied with the drive voltage signal VCV and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VCV, a constant current circuit co4-3 having one end supplied with the drive voltage signal VCV and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VCV, and a constant current circuit co4-4 having one end supplied with the drive voltage signal VCV and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VCV. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit co4-1 outputs a signal of a constant current value based on the drive voltage signal VCV, whether the constant current circuit co4-2 outputs a signal of a constant current value based on the drive voltage signal VCV, whether the constant current circuit co4-3 outputs a signal of a constant current value based on the drive voltage signal VCV, and whether the constant current circuit co4-4 outputs a signal of a constant current value based on the drive voltage signal VCV, thereby controlling the current value drawn by the output switching circuit 252-4 of the modified example.

[0183] Here, the switch SW4a-1 and the constant current circuit CI4-1 may be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch SW4a-2 and the constant current circuit CI4-2, the switch SW4a-3 and the constant current circuit CI4-3, and the switch SW4a-4 and the constant current circuit CI4-4 may each be configured with separate circuit elements or may be configured with one circuit element. Also, the switch SW4b-1 and the constant current circuit CO4-1 may each be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch SW4b-2 and the constant current circuit CO4-2, the switch SW4b-3 and the constant current circuit CO4-3, and the switch SW4b-4 and the constant current circuit CO4-4 may each be configured with separate circuit elements or may be configured with one circuit element.

[0184] In addition, the output switching circuit 252-5 of the modified example has a pair of a switch sw5a-1 and a constant current circuit ci5-1, a pair of a switch sw5a-2 and a constant current circuit ci5-2, a pair of a switch sw5a-3 and a constant current circuit ci5-3, a pair of a switch sw5a-4 and a constant current circuit ci5-4, a pair of a switch sw5b-1 and a constant current circuit co5-1, a pair of a switch sw5b-2 and a constant current circuit co5-2, a pair of a switch sw5b-3 and a constant current circuit co5-3, and a pair of a switch sw5b-4 and a constant current circuit co5-4, all connected in parallel between the wiring pattern to which the drive voltage signal VBV1 is supplied and the wiring pattern to which the drive signal VOUT is output.

[0185] Each of the pair of switch sw5a-1 and constant current circuit ci5-1, the pair of switch sw5a-2 and constant current circuit ci5-2, the pair of switch sw5a-3 and constant current circuit ci5-3, and the pair of switch sw5a-4 and constant current circuit ci5-4 switches whether or not to output a signal of a constant current value based on voltage Vb1 and the voltage value of the output terminal from output switching circuit 252-5 based on the logical level of voltage selection signal S5a [S5a-1, S5a-2, S5a-3, S5a-4] as voltage selection signal S. Similarly, the pair of switch sw5b-1 and constant current circuit co5-1, the pair of switch sw5b-2 and constant current circuit co5-2, the pair of switch sw5b-3 and constant current circuit co5-3, and the pair of switch sw5b-4 and constant current circuit co5-4 each switch whether or not to draw a signal of a constant current value based on the voltage value of the input terminal and voltage Vb1 into the output switching circuit 252-5 based on the logical level of the voltage selection signal S5b [S5b-1, S5b-2, S5b-3, S5b-4] as the voltage selection signal S.

[0186] Therefore, the output switching circuit 252-5 of the modified example can control the current value output to the discharge portion 600 according to the logical level of the voltage selection signal S5a [S5a-1, S5a-2, S5a-3, S5a-4] as the voltage selection signal S output by the waveform selection control circuit 210, and can control the current value drawn from the discharge portion 600 according to the logical level of the voltage selection signal S5b [S5b-1, S5b-2, S5b-3, S5b-4] as the voltage selection signal S output by the waveform selection control circuit 210.

[0187] That is, the output switching circuit 252-5 of the modified example has a constant current circuit ci5-1 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV1, a constant current circuit ci5-2 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV1, a constant current circuit ci5-3 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV1, and a constant current circuit ci5-4 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV1. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit ci5-1 outputs a signal of a constant current value based on the drive voltage signal VBV1, whether the constant current circuit ci5-2 outputs a signal of a constant current value based on the drive voltage signal VBV1, whether the constant current circuit ci5-3 outputs a signal of a constant current value based on the drive voltage signal VBV1, and whether the constant current circuit ci5-4 outputs a signal of a constant current value based on the drive voltage signal VBV1, thereby controlling the current value output from the output switching circuit 252-5 of the modified example.

[0188] In addition, the output switching circuit 252-5 of the modified example has a constant current circuit co5-1 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV1, a constant current circuit co5-2 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV1, a constant current circuit co5-3 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV1, and a constant current circuit co5-4 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV1. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit co5-1 outputs a signal of a constant current value based on the drive voltage signal VBV1, whether the constant current circuit co5-2 outputs a signal of a constant current value based on the drive voltage signal VBV1, whether the constant current circuit co5-3 outputs a signal of a constant current value based on the drive voltage signal VBV1, and whether the constant current circuit co5-4 outputs a signal of a constant current value based on the drive voltage signal VBV1, thereby controlling the current value drawn by the output switching circuit 252-5 of the modified example.

[0189] Here, the switch SW5a-1 and the constant current circuit CI5-1 may be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch SW5a-2 and the constant current circuit CI5-2, the switch SW5a-3 and the constant current circuit CI5-3, and the switch SW5a-4 and the constant current circuit CI5-4 may each be configured with separate circuit elements or may be configured with one circuit element. Also, the switch SW5b-1 and the constant current circuit CO5-1 may each be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch SW5b-2 and the constant current circuit CO5-2, the switch SW5b-3 and the constant current circuit CO5-3, and the switch SW5b-4 and the constant current circuit CO5-4 may each be configured with separate circuit elements or may be configured with one circuit element.

[0190] In addition, the output switching circuit 252-6 of the modified example has a pair of a switch sw6a-1 and a constant current circuit ci6-1, a pair of a switch sw6a-2 and a constant current circuit ci6-2, a pair of a switch sw6a-3 and a constant current circuit ci6-3, a pair of a switch sw6a-4 and a constant current circuit ci6-4, a pair of a switch sw6b-1 and a constant current circuit co6-1, a pair of a switch sw6b-2 and a constant current circuit co6-2, a pair of a switch sw6b-3 and a constant current circuit co6-3, and a pair of a switch sw6b-4 and a constant current circuit co6-4, which are connected in parallel between the wiring pattern to which the drive voltage signal VBV2 is supplied and the wiring pattern to which the drive signal VOUT is output.

[0191] The pair of switch sw6a-1 and constant current circuit ci6-1, the pair of switch sw6a-2 and constant current circuit ci6-2, the pair of switch sw6a-3 and constant current circuit ci6-3, and the pair of switch sw6a-4 and constant current circuit ci6-4 each switch whether or not to output a signal of a constant current value based on the voltage Vb2 and the voltage value of the output terminal from the output switching circuit 252-6 based on the logical level of the voltage selection signal S6a [S6a-1, S6a-2, S6a-3, S6a-4] as the voltage selection signal S. Similarly, the pair of switch sw6b-1 and constant current circuit co6-1, the pair of switch sw6b-2 and constant current circuit co6-2, the pair of switch sw6b-3 and constant current circuit co6-3, and the pair of switch sw6b-4 and constant current circuit co6-4 each switch whether or not to draw a constant current signal based on the voltage value of the input terminal and voltage Vb2 into the output switching circuit 252-6 based on the logical level of voltage selection signal S6b [S6b-1, S6b-2, S6b-3, S6b-4] as voltage selection signal S.

[0192] Therefore, the output switching circuit 252-6 of the modified example can control the current value output to the discharge portion 600 according to the logical level of the voltage selection signal S6a [S6a-1, S6a-2, S6a-3, S6a-4] as the voltage selection signal S output by the waveform selection control circuit 210, and can control the current value drawn from the discharge portion 600 according to the logical level of the voltage selection signal S6b [S6b-1, S6b-2, S6b-3, S6b-4] as the voltage selection signal S output by the waveform selection control circuit 210.

[0193] That is, the output switching circuit 252-6 of the modified example has a constant current circuit ci6-1 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV2, a constant current circuit ci6-2 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV2, a constant current circuit ci6-3 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV2, and a constant current circuit ci6-4 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV2. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit ci6-1 outputs a signal of a constant current value based on the drive voltage signal VBV2, whether the constant current circuit ci6-2 outputs a signal of a constant current value based on the drive voltage signal VBV2, whether the constant current circuit ci6-3 outputs a signal of a constant current value based on the drive voltage signal VBV2, and whether the constant current circuit ci6-4 outputs a signal of a constant current value based on the drive voltage signal VBV2, thereby controlling the current value output from the output switching circuit 252-6 of the modified example.

[0194] In addition, the output switching circuit 252-6 of the modified example has a constant current circuit co6-1 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV2, a constant current circuit co6-2 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV2, a constant current circuit co6-3 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV2, and a constant current circuit co6-4 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV2. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit co6-1 outputs a signal of a constant current value based on the drive voltage signal VBV2, whether the constant current circuit co6-2 outputs a signal of a constant current value based on the drive voltage signal VBV2, whether the constant current circuit co6-3 outputs a signal of a constant current value based on the drive voltage signal VBV2, and whether the constant current circuit co6-4 outputs a signal of a constant current value based on the drive voltage signal VBV2, thereby controlling the current value drawn by the output switching circuit 252-6 of the modified example.

[0195] Here, the switch SW6a-1 and the constant current circuit CI6-1 may be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch SW6a-2 and the constant current circuit CI6-2, the switch SW6a-3 and the constant current circuit CI6-3, and the switch SW6a-4 and the constant current circuit CI6-4 may each be configured with separate circuit elements or may be configured with one circuit element. Also, the switch SW6b-1 and the constant current circuit CO6-1 may each be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch SW6b-2 and the constant current circuit CO6-2, the switch SW6b-3 and the constant current circuit CO6-3, and the switch SW6b-4 and the constant current circuit CO6-4 may each be configured with separate circuit elements or may be configured with one circuit element.

[0196] Fig. 16 is a diagram showing the configuration of an output switching circuit 252-7 of the modified example. As shown in Fig. 16, the output switching circuit 252-7 of the modified example includes switches sw7b-1 to sw7b-4 and constant current circuits co7-1 to co7-4. Furthermore, voltage selection signals S7-1, S7-2, S7-3, and S7-4 as the voltage selection signal S7 and a drive voltage signal VBV3 are input to the output switching circuit 252-7 of the modified example.

[0197] The voltage selection signal S7-1 is input to the control terminal of the switch sw7b-1. The voltage selection signal S7-2 is input to the control terminal of the switch sw7b-2. The voltage selection signal S7-3 is input to the control terminal of the switch sw7b-3. The voltage selection signal S7-4 is input to the control terminal of the switch sw7b-4. The drive voltage signal VBV3 is input to one terminal of the switches sw7b-1 to sw7b-4. The other terminal of the switch sw7b-1 is electrically connected to the output terminal of the constant current circuit co7-1. The other terminal of the switch sw7b-2 is electrically connected to the output terminal of the constant current circuit co7-2. The other terminal of the switch sw7b-3 is electrically connected to the output terminal of the constant current circuit co7-3. The other terminal of the switch sw7b-4 is electrically connected to the output terminal of the constant current circuit co7-4.

[0198] In the output switching circuit 252-7 of the modified example configured as above, when the voltage selection signal S7-1 of H level is input to the control terminal of the switch sw7b-1, one terminal and the other terminal of the switch sw7b-1 are controlled to be conductive. As a result, the drive voltage signal VBV3 is supplied to the output terminal of the constant current circuit co7-1, and the constant current circuit co7-1 outputs a signal of a constant current value based on the voltage value of the input terminal and the voltage Vb3 supplied to the output terminal from the output terminal.

[0199] When an H-level voltage selection signal S7-2 is input to the control terminal of the switch sw7b-2, one terminal and the other terminal of the switch sw7b-2 are controlled to be conductive, whereby the drive voltage signal VBV3 is supplied to the input terminal of the constant current circuit co7-2, and the constant current circuit co7-2 outputs a signal of a constant current value from its output terminal based on the voltage value of the input terminal and the voltage Vb3 supplied to the output terminal.

[0200] When an H-level voltage selection signal S7-3 is input to the control terminal of the switch sw7b-3, one terminal and the other terminal of the switch sw7b-3 are controlled to be conductive, whereby the drive voltage signal VBV3 is supplied to the input terminal of the constant current circuit co7-3, and the constant current circuit co7-3 outputs a signal of a constant current value from its output terminal based on the voltage value of the input terminal and the voltage Vb3 supplied to the output terminal.

[0201] When an H-level voltage selection signal S7-4 is input to the control terminal of the switch sw7b-4, one terminal and the other terminal of the switch sw7b-4 are controlled to be conductive, whereby the drive voltage signal VBV3 is supplied to the input terminal of the constant current circuit co7-4, and the constant current circuit co7-4 outputs a signal of a constant current value from its output terminal based on the voltage value of the input terminal and the voltage Vb3 supplied to the output terminal.

[0202] That is, in the output switching circuit 252-7 of the modified example, a set of a switch sw7b-1 and a constant current circuit co7-1, a set of a switch sw7b-2 and a constant current circuit co7-2, a set of a switch sw7b-3 and a constant current circuit co7-3, and a set of a switch sw7b-4 and a constant current circuit co7-4 are connected in parallel between a wiring pattern to which the drive voltage signal VBV3 is supplied and a wiring pattern to which the drive signal VOUT is output. Then, by individually switching the conductive state of the switches sw7b-1 to sw7b-4 based on the logical levels of the voltage selection signals S7-1 to S7-4, the output switching circuit 252-7 of the modified example can be switched to output or not output a signal of a constant current value based on the voltage value of the input terminal and the voltage Vb3.

[0203] Here, in the following description, the voltage selection signal S7-1 input to the control end of switch sw7b-1, the voltage selection signal S7-2 input to the control end of switch sw7b-2, the voltage selection signal S7-3 input to the control end of switch sw7b-3, and the voltage selection signal S7-4 input to the control end of switch sw7b-4 may be collectively referred to as voltage selection signals S7[S7-1, S7-2, S7-3, S7-4].

[0204] When the voltage selection signal S7 [S7-1, S7-2, S7-3, S7-4] = [H, L, L, L] is input to the output switching circuit 252-7 of the modified example configured as above, the switch sw7b-1 is controlled so that one end and the other end are conductive, and the switches sw7b-2 to sw7b-4 are controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-7 draws a constant signal from the discharge unit 600 at a current value determined by the constant current circuit co7-1 based on the voltage value of the input terminal and the voltage Vb3.

[0205] In addition, when the voltage selection signal S7 [S7-1, S7-2, S7-3, S7-4] = [H, H, L, L] is input to the output switching circuit 252-7 of the modified example, the switches sw7b-1 and sw7b-2 are controlled so that one end and the other end are conductive, and the switches sw7b-3 and sw7b-4 are controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-7 draws a constant signal from the discharge unit 600 with a current value that is the sum of the current value determined by the constant current circuit co7-1 and the current value determined by the constant current circuit co7-2 based on the voltage value of the input terminal and the voltage Vb3.

[0206] In addition, when the voltage selection signal S7 [S7-1, S7-2, S7-3, S7-4] = [H, H, H, L] is input to the output switching circuit 252-7 of the modified example, the switches sw7b-1 to sw7b-3 are controlled so that one end and the other end are conductive, and the switch sw7b-4 is controlled so that one end and the other end are non-conductive. At this time, the output switching circuit 252-7 draws a constant signal from the discharge unit 600 with a current value that is the sum of the current value determined by the constant current circuit co7-1, the current value determined by the constant current circuit co7-2, and the current value determined by the constant current circuit co7-3 based on the voltage value of the input terminal and the voltage Vh3.

[0207] In addition, when the voltage selection signal S7 [S7-1, S7-2, S7-3, S7-4] = [H, H, H, H] is input to the output switching circuit 252-7 of the modified example, the switches sw7b-1 to sw7b-4 are controlled so that one end and the other end are conductive. At this time, the output switching circuit 252-7 draws a constant signal from the discharge unit 600 with a current value that is the sum of the current value determined by the constant current circuit co7-1, the current value determined by the constant current circuit co7-2, the current value determined by the constant current circuit co7-3, and the current value determined by the constant current circuit co7-4 based on the voltage value of the input end and the voltage Vb3.

[0208] As a result, the output switching circuit 252-7 of the modified example can control the current value drawn from the discharge section 600 according to the logic level of the voltage selection signal S7 [S7-1, S7-2, S7-3, S7-4] as the voltage selection signal S output by the waveform selection control circuit 210. Here, the switch sw7b-1 and the constant current circuit co7-1 may be configured with separate circuit elements or may be configured with one circuit element. Similarly, the switch sw7b-2 and the constant current circuit co7-2, the switch sw7b-3 and the constant current circuit co7-3, and the switch sw7b-4 and the constant current circuit co7-4 may each be configured with separate circuit elements or may be configured with one circuit element.

[0209] That is, the output switching circuit 252-7 of the modified example has a constant current circuit co7-1 having one end supplied with the drive voltage signal VBV3 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV3, a constant current circuit co7-2 having one end supplied with the drive voltage signal VBV3 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV3, a constant current circuit co7-3 having one end supplied with the drive voltage signal VBV3 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV3, and a constant current circuit co7-4 having one end supplied with the drive voltage signal VBV3 and the other end electrically connected to the piezoelectric element 60 of the discharge section 600, and outputting a signal of a constant current value based on the drive voltage signal VBV3. Then, based on the print data signal SI, the waveform selection control circuit 210 controls whether the constant current circuit co7-1 outputs a signal of a constant current value based on the drive voltage signal VBV3, whether the constant current circuit co7-2 outputs a signal of a constant current value based on the drive voltage signal VBV3, whether the constant current circuit co7-3 outputs a signal of a constant current value based on the drive voltage signal VBV3, and whether the constant current circuit co7-4 outputs a signal of a constant current value based on the drive voltage signal VBV3, thereby controlling the current value drawn by the output switching circuit 252-7 of the modified example.

[0210] In the liquid ejection device 1 of the modified example configured as above, each of the output switching circuits 252-1 to 252-7 of the output circuit 250 can control the current value supplied to the ejection section 600 and the current value drawn from the ejection section 600, thereby controlling the slope of the signal waveform of the drive signal VOUT to be output. Fig. 17 is a diagram showing an example of the relationship between the slope of the signal waveform of the drive signal VOUT and the voltage control signal of the modified example.

[0211] The piezoelectric element 60 to which the drive signal VOUT is supplied is a capacitive load, and therefore the voltage value supplied to the piezoelectric element 60 is the amount of charge stored in the piezoelectric element 60, and is proportional to the amount of current of the drive signal VOUT supplied to the piezoelectric element 60. Therefore, as in the liquid ejection device 1 of the modified example, each of the output switching circuits 252-1 to 252-7 of the output circuit 250 controls the current value supplied to the ejection section 600 and the current value drawn from the ejection section 600, thereby controlling the slope of the signal waveform of the drive signal VOUT output by the drive signal output circuit 200.

[0212] For example, when the voltage selection signal S7[S7-1, S7-2, S7-3, S7-4]=[H, H, H, H], the output switching circuit 252-7 draws a constant signal from the output unit 600 at a current value that is the sum of a current value determined by the constant current circuit co7-1, a current value determined by the constant current circuit co7-2, a current value determined by the constant current circuit co7-3, and a current value determined by the constant current circuit co7-4 based on the voltage value of the input terminal and the voltage Vb3. On the other hand, when the voltage selection signal S7[S7-1, S7-2, S7-3, S7-4]=[H, L, L, L], the output switching circuit 252-7 draws a constant signal from the output unit 600 at a current value determined by the constant current circuit co7-1 based on the voltage value of the input terminal and the voltage Vb3. In other words, when the voltage selection signal S7[S7-1, S7-2, S7-3, S7-4]=[H, H, H, H], the amount of current that the output switching circuit 252-7 draws from the discharge portion 600 is greater than the amount of current that the output switching circuit 252-7 draws from the discharge portion 600 when the voltage selection signal S7[S7-1, S7-2, S7-3, S7-4]=[H, L, L, L]. Therefore, as shown in FIG. 17, when the voltage value of the drive waveform DEP changes from voltage Vc to voltage Vb3 during period pa2, by inputting a voltage selection signal S7[S7-1, S7-2, S7-3, S7-4]=[H, H, H, H] to the output circuit 250, the voltage value of the drive waveform DEP can be changed more sharply compared to when a voltage selection signal S7[S7-1, S7-2, S7-3, S7-4]=[H, L, L, L] is input.

[0213] Also, for example, when the voltage selection signal S2a [S2a-1, S2a-2, S2a-3, S2a-4] = [H, H, H, L], the output switching circuit 252-2 supplies a constant signal with a sum of a current value specified by the constant current circuit ci2-1, a current value specified by the constant current circuit ci2-2, and a current value specified by the constant current circuit ci2-3 based on the voltage Vh2 and the voltage value of the output terminal to the output unit 600. On the other hand, when the voltage selection signal S2a [S2a-1, S2a-2, S2a-3, S2a-4] = [H, H, L, L], the output switching circuit 252-2 supplies a constant signal with a sum of a current value specified by the constant current circuit ci2-1 and a current value specified by the constant current circuit ci2-2 based on the voltage Vh2 and the voltage value of the output terminal to the output unit 600. In other words, when the voltage selection signal S2a[S2a-1, S2a-2, S2a-3, S2a-4]=[H, H, H, L], the amount of current supplied by the output switching circuit 252-2 to the discharge section 600 is greater than the amount of current supplied by the output switching circuit 252-2 to the discharge section 600 when the voltage selection signal S2a[S2a-1, S2a-2, S2a-3, S2a-4]=[H, H, L, L]. Therefore, as shown in FIG. 17, during period pc2, when the voltage value of the drive waveform NVT changes from voltage Vc to voltage Vh2, by inputting voltage selection signal S2a[S2a-1, S2a-2, S2a-3, S2a-4]=[H, H, H, L] to output circuit 250, the voltage value of the drive waveform NVT can be changed more sharply compared to when voltage selection signal S2a[S2a-1, S2a-2, S2a-3, S2a-4]=[H, H, L, L] is input.

[0214] As described above, in the liquid ejection device 1 of the modified example, it is possible to control the slope of the voltage change of the drive waveforms DEP, BSD, and NVT included in the drive signal VOUT. This allows the drive signal output circuit 200 in the liquid ejection device 1 of the modified example to output an optimal waveform of the drive signal VOUT according to the usage environment of the liquid ejection device 1 and the physical properties of the ink used. Therefore, in addition to the above-mentioned effects, the liquid ejection device 1 of the modified example can enhance the versatility of the liquid ejection device 1.

[0215] 2. Second embodiment Next, the configuration of the liquid ejection device 1 of the second embodiment will be described. The liquid ejection device 1 of the second embodiment differs from the liquid ejection device 1 of the first embodiment in the configuration of the output circuit 250 of the drive signal output circuit 200. Here, in describing the liquid ejection device 1 of the second embodiment, the same components as those of the liquid ejection device 1 of the first embodiment are given the same reference numerals, and the description thereof will be simplified or omitted. In addition, in the liquid ejection device 1 of the second embodiment, the waveform selection control circuit 210 of the drive signal output circuit 200 generates voltage selection signals S11 to S17 as the voltage selection signal S based on the latch signal LAT, the change signal CH, the clock signal SCK, the print data signal SI, and the waveform selection signal WS, and outputs them to the corresponding output circuit 250. In addition, the output circuit 250 of the liquid ejection device 1 of the second embodiment will be described as having an output switching circuit 252a-1 equivalent to the output switching circuit 252-1 that selects whether to output the drive voltage signal VHV3 in the liquid ejection device 1 of the first embodiment, an output switching circuit 252a-2 equivalent to the output switching circuit 252-2 that selects whether to output the drive voltage signal VHV2, an output switching circuit 252a-3 equivalent to the output switching circuit 252-3 that selects whether to output the drive voltage signal VHV1, an output switching circuit 252a-4 equivalent to the output switching circuit 252-4 that selects whether to output the drive voltage signal VCV, an output switching circuit 252a-5 equivalent to the output switching circuit 252-5 that selects whether to output the drive voltage signal VBV1, an output switching circuit 252a-6 equivalent to the output switching circuit 252-6 that selects whether to output the drive voltage signal VBV2, and an output switching circuit 252a-7 equivalent to the output switching circuit 252-7 that selects whether to output the drive voltage signal VBV3.

[0216] 2.1 Configuration of the output circuit of the second embodiment Fig. 18 is a diagram showing an example of the configuration of an output circuit 250 according to the second embodiment. As shown in Fig. 18, the output circuit 250 has output switching circuits 252a-1 to 252a-7, similar to the first embodiment.

[0217] The output switching circuit 252a-1 of the second embodiment includes an inverter inv1 and a transfer gate tg1. A voltage selection signal S11 as the voltage selection signal S and a drive voltage signal VHV3 are input to the output switching circuit 252a-1. The voltage selection signal S11 is input to a positive control terminal of the transfer gate tg1, and is also input to a negative control terminal marked with a circle of the transfer gate tg1 after its logical level is inverted by the inverter inv1. The drive voltage signal VHV3 is input to an input terminal of the transfer gate tg1.

[0218] When an H-level voltage selection signal S11 is input to the output switching circuit 252a-1, the input terminal and output terminal of the transfer gate tg1 are conductive, and when an L-level voltage selection signal S11 is input, the input terminal and output terminal of the transfer gate tg1 are non-conductive. That is, when an H-level voltage selection signal S11 is input to the output switching circuit 252a-1, the transfer gate tg1 supplies a current to the discharge portion 600 or draws a current from the discharge portion 600 so that the voltage value of the drive signal VOUT becomes the voltage Vh3, which is the voltage value of the drive voltage signal VHV3.

[0219] In other words, the waveform selection control circuit 210 controls the output switching circuit 252a-1 based on the print data signal SI, and the output switching circuit 252a-1 switches whether or not the drive voltage signal VHV3 is supplied to the ejection section 600.

[0220] The output switching circuit 252a-2 of the second embodiment includes an inverter inv2 and a transfer gate tg2. A voltage selection signal S12 as the voltage selection signal S and a drive voltage signal VHV2 are input to the output switching circuit 252a-2. The voltage selection signal S12 is input to a positive control terminal of the transfer gate tg2, and is also input to a negative control terminal marked with a circle of the transfer gate tg2 after its logical level is inverted by the inverter inv2. The drive voltage signal VHV2 is input to an input terminal of the transfer gate tg2.

[0221] When an H-level voltage selection signal S12 is input to such an output switching circuit 252a-1, conduction occurs between the input terminal and output terminal of the transfer gate tg2, and when an L-level voltage selection signal S12 is input, conduction occurs between the input terminal and output terminal of the transfer gate tg2. In other words, when an H-level voltage selection signal S12 is input to the output switching circuit 252a-2, the transfer gate tg2 supplies a current to the discharge portion 600 or draws a current from the discharge portion 600 so that the voltage value of the drive signal VOUT becomes the voltage Vh2, which is the voltage value of the drive voltage signal VHV2.

[0222] In other words, the waveform selection control circuit 210 controls the output switching circuit 252a-2 based on the print data signal SI, and the output switching circuit 252a-2 switches whether or not the drive voltage signal VHV2 is supplied to the ejection section 600.

[0223] The output switching circuit 252a-3 of the second embodiment includes an inverter inv3 and a transfer gate tg3. A voltage selection signal S13 as the voltage selection signal S and a drive voltage signal VHV1 are input to the output switching circuit 252a-3. The voltage selection signal S13 is input to a positive control terminal of the transfer gate tg3, and is also input to a negative control terminal marked with a circle of the transfer gate tg3 after its logical level is inverted by the inverter inv3. The drive voltage signal VHV1 is input to an input terminal of the transfer gate tg3.

[0224] When an H-level voltage selection signal S13 is input to such an output switching circuit 252a-3, conduction occurs between the input terminal and output terminal of the transfer gate tg3, and when an L-level voltage selection signal S13 is input, conduction occurs between the input terminal and output terminal of the transfer gate tg3. In other words, when an H-level voltage selection signal S13 is input to the output switching circuit 252a-3, the transfer gate tg3 supplies a current to the discharge portion 600 or draws a current from the discharge portion 600 so that the voltage value of the drive signal VOUT becomes the voltage Vh1, which is the voltage value of the drive voltage signal VHV1.

[0225] In other words, the waveform selection control circuit 210 controls the output switching circuit 252a-3 based on the print data signal SI, and the output switching circuit 252a-3 switches whether or not the drive voltage signal VHV1 is supplied to the ejection section 600.

[0226] The output switching circuit 252a-4 of the second embodiment includes an inverter inv4 and a transfer gate tg4. A voltage selection signal S14 as the voltage selection signal S and a drive voltage signal VCV are input to the output switching circuit 252a-4. The voltage selection signal S14 is input to a positive control terminal of the transfer gate tg4, and is also input to a negative control terminal marked with a circle of the transfer gate tg4 after its logical level is inverted by the inverter inv4. The drive voltage signal VCV is input to an input terminal of the transfer gate tg4.

[0227] When an H-level voltage selection signal S14 is input to such an output switching circuit 252a-4, conduction occurs between the input terminal and output terminal of the transfer gate tg4, and when an L-level voltage selection signal S14 is input, conduction occurs between the input terminal and output terminal of the transfer gate tg4. In other words, when an H-level voltage selection signal S14 is input to the output switching circuit 252a-4, the transfer gate tg4 supplies a current to the discharge portion 600 or draws a current from the discharge portion 600 so that the voltage value of the drive signal VOUT becomes the voltage Vc, which is the voltage value of the drive voltage signal VCV.

[0228] In other words, the waveform selection control circuit 210 controls the output switching circuit 252a-4 based on the print data signal SI, and the output switching circuit 252a-4 switches whether or not the drive voltage signal VCV is supplied to the ejection portion 600.

[0229] The output switching circuit 252a-5 of the second embodiment includes an inverter inv5 and a transfer gate tg5. A voltage selection signal S15 as the voltage selection signal S and a drive voltage signal VBV1 are input to the output switching circuit 252a-5. The voltage selection signal S15 is input to a positive control terminal of the transfer gate tg5, and is also input to a negative control terminal marked with a circle of the transfer gate tg5 after its logical level is inverted by the inverter inv5. The drive voltage signal VBV1 is input to an input terminal of the transfer gate tg5.

[0230] When an H-level voltage selection signal S15 is input to such an output switching circuit 252a-5, conduction occurs between the input terminal and output terminal of the transfer gate tg5, and when an L-level voltage selection signal S15 is input, conduction occurs between the input terminal and output terminal of the transfer gate tg5. In other words, when an H-level voltage selection signal S15 is input to the output switching circuit 252a-5, the transfer gate tg5 supplies a current to the discharge portion 600 or draws a current from the discharge portion 600 so that the voltage value of the drive signal VOUT becomes voltage Vb1, which is the voltage value of the drive voltage signal VBV1.

[0231] In other words, the waveform selection control circuit 210 controls the output switching circuit 252a-5 based on the print data signal SI, and the output switching circuit 252a-5 switches whether or not the drive voltage signal VBV1 is supplied to the ejection section 600.

[0232] The output switching circuit 252a-6 of the second embodiment includes an inverter inv6 and a transfer gate tg6. A voltage selection signal S16 as the voltage selection signal S and a drive voltage signal VBV2 are input to the output switching circuit 252a-6. The voltage selection signal S16 is input to a positive control terminal of the transfer gate tg6, and is also input to a negative control terminal marked with a circle of the transfer gate tg6 after its logical level is inverted by the inverter inv6. The drive voltage signal VBV2 is input to an input terminal of the transfer gate tg6.

[0233] When an H-level voltage selection signal S16 is input to such an output switching circuit 252a-6, conduction occurs between the input terminal and output terminal of the transfer gate tg6, and when an L-level voltage selection signal S16 is input, conduction occurs between the input terminal and output terminal of the transfer gate tg6. In other words, when an H-level voltage selection signal S16 is input to the output switching circuit 252a-6, the transfer gate tg6 supplies a current to the discharge portion 600 or draws a current from the discharge portion 600 so that the voltage value of the drive signal VOUT becomes the voltage Vb2, which is the voltage value of the drive voltage signal VBV2.

[0234] In other words, the waveform selection control circuit 210 controls the output switching circuit 252a-6 based on the print data signal SI, and the output switching circuit 252a-6 switches whether or not the drive voltage signal VBV2 is supplied to the ejection section 600.

[0235] The output switching circuit 252a-7 of the second embodiment includes an inverter inv7 and a transfer gate tg7. A voltage selection signal S17 as the voltage selection signal S and a drive voltage signal VBV3 are input to the output switching circuit 252a-7. The voltage selection signal S17 is input to a positive control terminal of the transfer gate tg7, and is also input to a negative control terminal marked with a circle of the transfer gate tg7 after its logical level is inverted by the inverter inv7. The drive voltage signal VBV3 is input to an input terminal of the transfer gate tg7.

[0236] When an H-level voltage selection signal S17 is input to such an output switching circuit 252a-7, the input terminal and output terminal of the transfer gate tg7 are conductive, and when an L-level voltage selection signal S17 is input, the input terminal and output terminal of the transfer gate tg7 are non-conductive. That is, when an H-level voltage selection signal S17 is input to the output switching circuit 252a-7, the transfer gate tg7 supplies a current to the discharge portion 600 or draws a current from the discharge portion 600 so that the voltage value of the drive signal VOUT becomes the voltage Vb3, which is the voltage value of the drive voltage signal VBV3.

[0237] In other words, the waveform selection control circuit 210 controls the output switching circuit 252a-7 based on the print data signal SI, and the output switching circuit 252a-7 switches whether or not the drive voltage signal VBV3 is supplied to the ejection section 600.

[0238] Even in the liquid ejection device 1 of the second embodiment having the output circuit 250 configured as described above, the waveform selection control circuit 210 outputs a voltage selection signal S of a predetermined logic level based on the latch signal LAT, the change signals CHA, CHB, CHC, CHD, the clock signal SCK, the print data signal SI, and the waveform information signal WI, and the output switching circuits 252a-1 to 252a-7 select or deselect each of the drive voltage signals VHV1, VHV2, VHV3, VCV, VBV1, VBV2, VBV1 based on the logic level of the input voltage selection signal S, thereby generating a drive signal VOUT and outputting it to the corresponding ejection section 600. As a result, even in the liquid ejection device 1 and head unit 20 of the second embodiment, it is possible to achieve the same effects as the liquid ejection device 1 of the first embodiment.

[0239] 2.2 Modification of the output circuit of the second embodiment In the second embodiment of the liquid ejection device 1 described above, the output switching circuit 252a-1 of the output circuit 250 has one pair of a transfer gate tg1 and an inverter inv1, and is described as switching the conductive state between one end and the other end of the transfer gate tg1 to switch whether or not to output the drive voltage signal VHV3 as the drive signal VOUT, but the output switching circuit 252a-1 may have multiple pairs of a transfer gate tg1 and an inverter inv1.

[0240] Similarly, the output switching circuit 252a-2 may have multiple pairs of transfer gate tg2 and inverter inv2, the output switching circuit 252a-3 may have multiple pairs of transfer gate tg3 and inverter inv3, the output switching circuit 252a-4 may have multiple pairs of transfer gate tg4 and inverter inv4, the output switching circuit 252a-5 may have multiple pairs of transfer gate tg5 and inverter inv5, the output switching circuit 252a-6 may have multiple pairs of transfer gate tg6 and inverter inv6, and the output switching circuit 252a-7 may have multiple pairs of transfer gate tg7 and inverter inv7.

[0241] A specific example of the configuration of a modified example of the liquid ejection device 1 of the second embodiment will be described. Fig. 19 is a diagram showing an example of the configuration of an output switching circuit 252a-1 of the modified example of the second embodiment. As shown in Fig. 19, the output switching circuit 252a-1 of the modified example of the second embodiment includes transfer gates tg1-1 to tg1-4 and inverters inv1-1 to inv1-4. Furthermore, voltage selection signals S11-1, S11-2, S11-3, and S11-4 as the voltage selection signal S11 and a drive voltage signal VHV3 are input to the output switching circuit 252a-1 of the modified example of the second embodiment.

[0242] The voltage selection signal S11-1 is input to the positive control terminal of the transfer gate tg1-1, and is also input to the negative control terminal marked with a circle of the transfer gate tg1-1 after the logic level is inverted by the inverter inv1-1. The drive voltage signal VHV3 is input to the input terminal of the transfer gate tg1-1. The voltage selection signal S11-2 is input to the positive control terminal of the transfer gate tg1-2, and is also input to the negative control terminal marked with a circle of the transfer gate tg1-2 after the logic level is inverted by the inverter inv1-2. The drive voltage signal VHV3 is input to the input terminal of the transfer gate tg1-2. The voltage selection signal S11-3 is input to the positive control terminal of the transfer gate tg1-3, and is also input to the negative control terminal marked with a circle of the transfer gate tg1-3 after the logic level is inverted by the inverter inv1-3. A drive voltage signal VHV3 is input to the input terminal of the transfer gate tg1-3. The voltage selection signal S11-4 is input to the positive control terminal of the transfer gate tg1-4, and is also input to the negative control terminal marked with a circle of the transfer gate tg1-4 after the logic level is inverted by the inverter inv1-4. A drive voltage signal VHV3 is input to the input terminal of the transfer gate tg1-4. In the output switching circuit 252a-2, the output terminals of the transfer gates tg1-1 to tg1-4 are commonly connected. The output switching circuit 252a-1 of the modified example of the second embodiment outputs the signal of the output terminals of the commonly connected transfer gates tg1-1 to tg1-4 as a drive signal VOUT to the corresponding ejection section 600.

[0243] When an H-level voltage selection signal S11-1 is input to the output switching circuit 252a-1 of the modified example of the second embodiment configured as described above, one end and the other end of the transfer gate tg1-1 are controlled to be conductive, and when an L-level voltage selection signal S11-1 is input, one end and the other end of the transfer gate tg1-1 are controlled to be non-conductive. Similarly, when an H-level voltage selection signal S11-2 is input to the output switching circuit 252a-1 of the modified example of the second embodiment, one end and the other end of the transfer gate tg1-2 are controlled to be conductive, and when an L-level voltage selection signal S11-2 is input, one end and the other end of the transfer gate tg1-2 are controlled to be non-conductive. Similarly, when an H-level voltage selection signal S11-3 is input to the output switching circuit 252a-1 of the modified example of the second embodiment, one end and the other end of the transfer gate tg1-3 are controlled to be conductive, and when an L-level voltage selection signal S11-3 is input, one end and the other end of the transfer gate tg1-3 are controlled to be non-conductive. Similarly, when an H-level voltage selection signal S11-4 is input to the output switching circuit 252a-1 of the modified example of the second embodiment, one end and the other end of the transfer gate tg1-4 are controlled to be conductive, and when an L-level voltage selection signal S11-4 is input, one end and the other end of the transfer gate tg1-4 are controlled to be non-conductive.

[0244] That is, in the output switching circuit 252a-1 of the modified example of the second embodiment, transfer gates tg1-1, tg1-2, tg1-3, and tg1-4 are connected in parallel between the wiring pattern to which the driving voltage signal VHV3 is supplied and the wiring pattern to which the driving signal VOUT is output. Then, each of the transfer gates tg1-1 to tg1-4 switches whether or not to output the driving signal VOUT corresponding to the voltage Vh3 based on the logical level of the corresponding voltage selection signal S11-1 to S11-4. Here, in the following description, the voltage selection signals S11-1 to S11-4 may be collectively referred to as the voltage selection signal S11 [S11-1, S11-2, S11-3, S11-4].

[0245] When the voltage selection signal S11 [S11-1, S11-2, S11-3, S11-4] = [H, L, L, L] is input to the output switching circuit 252a-1 of the modified example of the second embodiment configured as above, the transfer gate tg1-1 is controlled so that one end and the other end are conductive, and the transfer gates tg1-2 to tg1-4 are controlled so that one end and the other end are non-conductive. At this time, the voltage value of the drive signal VOUT output by the output switching circuit 252a-1 rises or falls toward the voltage Vh3 in a time according to a time constant determined by the resistance value of the on-resistance of the transfer gate tg1-1 and the capacitance component of the piezoelectric element 60 of the corresponding ejection part 600.

[0246] In addition, when the voltage selection signal S11 [S11-1, S11-2, S11-3, S11-4] = [H, H, L, L] is input to the output switching circuit 252a-1 of the modified example of the second embodiment, the transfer gates tg1-1 and tg1-2 are controlled to have one end and the other end conductive, and the transfer gates tg1-3 to tg1-4 are controlled to have one end and the other end non-conductive. At this time, the voltage value of the drive signal VOUT output by the output switching circuit 252a-1 rises or falls toward the voltage Vh3 in a time according to a time constant determined by the combined resistance value of the resistance value of the on-resistance of the transfer gate tg1-1 and the resistance value of the on-resistance of the transfer gate tg1-2, and the capacitance component of the piezoelectric element 60 of the corresponding ejection portion 600.

[0247] In addition, when the voltage selection signal S11 [S11-1, S11-2, S11-3, S11-4] = [H, H, H, L] is input to the output switching circuit 252a-1 of the modified example of the second embodiment, the transfer gates tg1-1 to tg1-3 are controlled to have one end and the other end conductive, and the transfer gate tg1-4 is controlled to have one end and the other end non-conductive. At this time, the voltage value of the drive signal VOUT output by the output switching circuit 252a-1 rises or falls toward the voltage Vh3 in a time corresponding to a time constant determined by the combined resistance value of the resistance value of the on-resistance of the transfer gate tg1-1, the resistance value of the on-resistance of the transfer gate tg1-2, and the resistance value of the on-resistance of the transfer gate tg1-1, and the capacitance component of the piezoelectric element 60 of the corresponding ejection portion 600.

[0248] In addition, when the voltage selection signal S11 [S11-1, S11-2, S11-3, S11-4] = [H, H, H, H] is input to the output switching circuit 252a-1 of the modified example of the second embodiment, the transfer gates tg1-1 to tg1-4 are controlled so that one end and the other end are conductive. At this time, the voltage value of the drive signal VOUT output by the output switching circuit 252a-1 rises or falls toward the voltage Vh3 in a time corresponding to a time constant determined by the combined resistance value of the resistance value of the on-resistance of the transfer gate tg1-1, the resistance value of the on-resistance of the transfer gate tg1-2, the resistance value of the on-resistance of the transfer gate tg1-3, and the resistance value of the on-resistance of the transfer gate tg1-4, and the capacitance component of the piezoelectric element 60 of the corresponding ejection portion 600.

[0249] That is, the output switching circuit 252a-1 of the modified example of the second embodiment controls the time at which the voltage value of the drive signal VOUT output by the output switching circuit 252a-1 changes toward the voltage Vh3, depending on the logical level of the input voltage selection signal S11 [S11-1, S11-2, S11-3, S11-4].

[0250] As described above, the output switching circuit 252a-1 of the modified example of the second embodiment includes a transfer gate tg1-1 having one end supplied with the drive voltage signal VHV3 and the other end electrically connected to the ejection section 600, a transfer gate tg1-2 having one end supplied with the drive voltage signal VHV3 and the other end electrically connected to the ejection section 600, a transfer gate tg1-3 having one end supplied with the drive voltage signal VHV3 and the other end electrically connected to the ejection section 600, and a transfer gate tg1-4 having one end supplied with the drive voltage signal VHV3 and the other end electrically connected to the ejection section 600. Then, the waveform selection control circuit 210 outputs voltage selection signal S11-1, voltage selection signal S11-2, voltage selection signal S11-3, and voltage selection signal S11-4 based on the print data signal SI, so that the conduction state between one end and the other end of transfer gate tg1-1 is controlled by voltage selection signal S11-1, the conduction state between one end and the other end of transfer gate tg1-2 is controlled by voltage selection signal S11-2, the conduction state between one end and the other end of transfer gate tg1-3 is controlled by voltage selection signal S11-3, and the conduction state between one end and the other end of transfer gate tg1-4 is controlled by voltage selection signal S11-4.

[0251] Here, the output switching circuits 252a-2 to 252a-7 of the modified example of the second embodiment have the same configuration as the output switching circuit 252a-1 of the modified example of the second embodiment, except for the input and output signals. Therefore, the configurations of the output switching circuits 252a-2 to 252a-7 of the modified example of the second embodiment are not shown in the figures, and the description will be simplified.

[0252] The output switching circuit 252a-2 of the modified example of the second embodiment receives the voltage selection signals S12-1 to S12-4 as the voltage selection signal S12 and the drive voltage signal VHV2. The output switching circuit 252a-2 of the modified example of the second embodiment has transfer gates tg2-1, tg2-2, tg2-3, and tg2-4 connected in parallel between the wiring pattern to which the drive voltage signal VHV2 is supplied and the wiring pattern to which the drive signal VOUT is output. Each of the transfer gates tg2-1 to tg2-4 of the output switching circuit 252a-2 of the modified example of the second embodiment switches whether or not to output the drive signal VOUT corresponding to the voltage Vh2 based on the logic level of the corresponding voltage selection signal S12-1 to S12-4. In the following description, the voltage selection signals S12-1 to S12-4 may be collectively referred to as voltage selection signal S12 [S12-1, S12-2, S12-3, S12-4].

[0253] The output switching circuit 252a-2 of the modified example of the second embodiment configured as described above, like the output switching circuit 252a-1 of the modified example of the second embodiment, controls the conduction state of each of the transfer gates tg2-1 to tg2-4 in accordance with the logic level of the input voltage selection signal S12 [S12-1, S12-2, S12-3, S12-4], thereby controlling the time during which the voltage value of the drive signal VOUT output by the output switching circuit 252a-2 changes toward the voltage Vh2.

[0254] That is, the output switching circuit 252a-2 of the modified example of the second embodiment includes a transfer gate tg2-1 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the ejection section 600, a transfer gate tg2-2 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the ejection section 600, a transfer gate tg2-3 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the ejection section 600, and a transfer gate tg2-4 having one end supplied with the drive voltage signal VHV2 and the other end electrically connected to the ejection section 600. Then, the waveform selection control circuit 210 outputs voltage selection signals S12-1, S12-2, S12-3, and S12-4 based on the print data signal SI, so that the conduction state between one end and the other end of transfer gate tg2-1 is controlled by voltage selection signal S12-1, the conduction state between one end and the other end of transfer gate tg2-2 is controlled by voltage selection signal S12-2, the conduction state between one end and the other end of transfer gate tg2-3 is controlled by voltage selection signal S12-3, and the conduction state between one end and the other end of transfer gate tg2-4 is controlled by voltage selection signal S12-4.

[0255] Similarly, the output switching circuit 252a-3 of the modified example of the second embodiment receives the voltage selection signals S13-1 to S13-4 as the voltage selection signal S13 and the drive voltage signal VHV1. The output switching circuit 252a-3 of the modified example of the second embodiment has transfer gates tg3-1, tg3-2, tg3-3, and tg3-4 connected in parallel between the wiring pattern to which the drive voltage signal VHV1 is supplied and the wiring pattern to which the drive signal VOUT is output. Each of the transfer gates tg3-1 to tg3-4 of the output switching circuit 252a-3 of the modified example of the second embodiment switches whether or not to output the drive signal VOUT corresponding to the voltage Vh1 based on the logic level of the corresponding voltage selection signal S13-1 to S13-4. In the following description, the voltage selection signals S13-1 to S13-4 may be collectively referred to as voltage selection signal S13 [S13-1, S13-2, S13-3, S13-4].

[0256] The output switching circuit 252a-3 of the modified example of the second embodiment configured as described above, like the output switching circuit 252a-1 of the modified example of the second embodiment, controls the conduction state of each of the transfer gates tg3-1 to tg3-4 in accordance with the logic level of the input voltage selection signal S13 [S13-1, S13-2, S13-3, S13-4], thereby controlling the time during which the voltage value of the drive signal VOUT output by the output switching circuit 252a-3 changes toward the voltage Vh1.

[0257] That is, the output switching circuit 252a-3 of the modified example of the second embodiment includes a transfer gate tg3-1 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the ejection section 600, a transfer gate tg3-2 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the ejection section 600, a transfer gate tg3-3 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the ejection section 600, and a transfer gate tg3-4 having one end supplied with the drive voltage signal VHV1 and the other end electrically connected to the ejection section 600. Then, the waveform selection control circuit 210 outputs voltage selection signal S13-1, voltage selection signal S13-2, voltage selection signal S13-3, and voltage selection signal S13-4 based on the print data signal SI, so that the conduction state between one end and the other end of transfer gate tg3-1 is controlled by voltage selection signal S13-1, the conduction state between one end and the other end of transfer gate tg3-2 is controlled by voltage selection signal S13-2, the conduction state between one end and the other end of transfer gate tg3-3 is controlled by voltage selection signal S13-3, and the conduction state between one end and the other end of transfer gate tg3-4 is controlled by voltage selection signal S13-4.

[0258] Similarly, the output switching circuit 252a-4 of the modified second embodiment receives the voltage selection signals S14-1 to S14-4 as the voltage selection signal S14 and the drive voltage signal VCV. The output switching circuit 252a-4 of the modified second embodiment has transfer gates tg4-1, tg4-2, tg4-3, and tg4-4 connected in parallel between the wiring pattern to which the drive voltage signal VCV is supplied and the wiring pattern to which the drive signal VOUT is output. Each of the transfer gates tg4-1 to tg4-4 of the output switching circuit 252a-4 of the modified second embodiment switches whether or not to output the drive signal VOUT according to the voltage Vc based on the logic level of the corresponding voltage selection signal S14-1 to S14-4. In the following description, the voltage selection signals S14-1 to S14-4 may be collectively referred to as voltage selection signal S14 [S14-1, S14-2, S14-3, S14-4].

[0259] The output switching circuit 252a-4 of the modified example of the second embodiment configured as described above, like the output switching circuit 252a-1 of the modified example of the second embodiment, controls the conduction state of each of the transfer gates tg4-1 to tg4-4 in accordance with the logic level of the input voltage selection signal S14 [S14-1, S14-2, S14-3, S14-4], thereby controlling the time during which the voltage value of the drive signal VOUT output by the output switching circuit 252a-4 changes toward the voltage Vc.

[0260] That is, the output switching circuit 252a-4 of the modified example of the second embodiment includes a transfer gate tg4-1 having one end supplied with the drive voltage signal VCV and the other end electrically connected to the ejection section 600, a transfer gate tg4-2 having one end supplied with the drive voltage signal VCV and the other end electrically connected to the ejection section 600, a transfer gate tg4-3 having one end supplied with the drive voltage signal VCV and the other end electrically connected to the ejection section 600, and a transfer gate tg4-4 having one end supplied with the drive voltage signal VCV and the other end electrically connected to the ejection section 600. Then, the waveform selection control circuit 210 outputs voltage selection signals S14-1, S14-2, S14-3, and S14-4 based on the print data signal SI, so that the conduction state between one end and the other end of transfer gate tg4-1 is controlled by voltage selection signal S14-1, the conduction state between one end and the other end of transfer gate tg4-2 is controlled by voltage selection signal S14-2, the conduction state between one end and the other end of transfer gate tg4-3 is controlled by voltage selection signal S14-3, and the conduction state between one end and the other end of transfer gate tg4-4 is controlled by voltage selection signal S14-4.

[0261] Similarly, the output switching circuit 252a-5 of the modified second embodiment receives the voltage selection signals S15-1 to S15-4 as the voltage selection signal S15 and the drive voltage signal VBV1. The output switching circuit 252a-5 of the modified second embodiment has transfer gates tg5-1, tg5-2, tg5-3, and tg5-4 connected in parallel between the wiring pattern to which the drive voltage signal VBV1 is supplied and the wiring pattern to which the drive signal VOUT is output. Each of the transfer gates tg5-1 to tg5-4 of the output switching circuit 252a-5 of the modified second embodiment switches whether or not to output the drive signal VOUT corresponding to the voltage Vb1 based on the logic level of the corresponding voltage selection signal S15-1 to S15-4. In the following description, the voltage selection signals S15-1 to S15-4 may be collectively referred to as voltage selection signal S15 [S15-1, S15-2, S15-3, S15-4].

[0262] The output switching circuit 252a-5 of the modified example of the second embodiment configured as described above, like the output switching circuit 252a-1 of the modified example of the second embodiment, controls the conduction state of each of the transfer gates tg5-1 to tg5-4 in accordance with the logic level of the input voltage selection signal S15 [S15-1, S15-2, S15-3, S15-4], thereby controlling the time during which the voltage value of the drive signal VOUT output by the output switching circuit 252a-5 changes toward the voltage Vb1.

[0263] That is, the output switching circuit 252a-5 of the modified example of the second embodiment includes a transfer gate tg5-1 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the ejection section 600, a transfer gate tg5-2 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the ejection section 600, a transfer gate tg5-3 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the ejection section 600, and a transfer gate tg5-4 having one end supplied with the drive voltage signal VBV1 and the other end electrically connected to the ejection section 600. Then, the waveform selection control circuit 210 outputs voltage selection signal S15-1, voltage selection signal S15-2, voltage selection signal S15-3, and voltage selection signal S15-4 based on the print data signal SI, so that the conduction state between one end and the other end of transfer gate tg5-1 is controlled by voltage selection signal S15-1, the conduction state between one end and the other end of transfer gate tg5-2 is controlled by voltage selection signal S15-2, the conduction state between one end and the other end of transfer gate tg5-3 is controlled by voltage selection signal S15-3, and the conduction state between one end and the other end of transfer gate tg5-4 is controlled by voltage selection signal S15-4.

[0264] Similarly, the output switching circuit 252a-6 of the modified second embodiment receives the voltage selection signals S16-1 to S16-4 as the voltage selection signal S16 and the drive voltage signal VBV2. The output switching circuit 252a-6 of the modified second embodiment also has transfer gates tg6-1, tg6-2, tg6-3, and tg6-4 connected in parallel between the wiring pattern to which the drive voltage signal VBV2 is supplied and the wiring pattern to which the drive signal VOUT is output. Each of the transfer gates tg6-1 to tg6-4 of the output switching circuit 252a-6 of the modified second embodiment switches whether or not to output the drive signal VOUT corresponding to the voltage Vb2 based on the logic level of the corresponding voltage selection signal S16-1 to S16-4. In the following description, the voltage selection signals S16-1 to S16-4 may be collectively referred to as voltage selection signal S16 [S16-1, S16-2, S16-3, S16-4].

[0265] The output switching circuit 252a-6 of the modified example of the second embodiment configured as described above, like the output switching circuit 252a-1 of the modified example of the second embodiment, controls the conduction state of each of the transfer gates tg6-1 to tg6-4 in accordance with the logic level of the input voltage selection signal S16 [S16-1, S16-2, S16-3, S16-4], thereby controlling the time during which the voltage value of the drive signal VOUT output by the output switching circuit 252a-6 changes toward the voltage Vb2.

[0266] That is, the output switching circuit 252a-6 of the modified example of the second embodiment includes a transfer gate tg6-1 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the ejection section 600, a transfer gate tg6-2 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the ejection section 600, a transfer gate tg6-3 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the ejection section 600, and a transfer gate tg6-4 having one end supplied with the drive voltage signal VBV2 and the other end electrically connected to the ejection section 600. Then, the waveform selection control circuit 210 outputs voltage selection signals S16-1, S16-2, S16-3, and S16-4 based on the print data signal SI, so that the conduction state between one end and the other end of transfer gate tg6-1 is controlled by voltage selection signal S16-1, the conduction state between one end and the other end of transfer gate tg6-2 is controlled by voltage selection signal S16-2, the conduction state between one end and the other end of transfer gate tg6-3 is controlled by voltage selection signal S16-3, and the conduction state between one end and the other end of transfer gate tg6-4 is controlled by voltage selection signal S16-4.

[0267] Similarly, the output switching circuit 252a-7 of the modified second embodiment receives the voltage selection signals S17-1 to S17-4 as the voltage selection signal S17 and the drive voltage signal VBV3. The output switching circuit 252a-7 of the modified second embodiment has transfer gates tg7-1, tg7-2, tg7-3, and tg7-4 connected in parallel between the wiring pattern to which the drive voltage signal VBV3 is supplied and the wiring pattern to which the drive signal VOUT is output. Each of the transfer gates tg7-1 to tg7-4 of the output switching circuit 252a-7 of the modified second embodiment switches whether or not to output the drive signal VOUT corresponding to the voltage Vb3 based on the logic level of the corresponding voltage selection signal S17-1 to S17-4. In the following description, the voltage selection signals S17-1 to S17-4 may be collectively referred to as voltage selection signal S17 [S17-1, S17-2, S17-3, S17-4].

[0268] The output switching circuit 252a-7 of the modified example of the second embodiment configured as described above, like the output switching circuit 252a-1 of the modified example of the second embodiment, controls the conduction state of each of the transfer gates tg7-1 to tg7-4 in accordance with the logic level of the input voltage selection signal S17 [S17-1, S17-2, S17-3, S17-4], thereby controlling the time during which the voltage value of the drive signal VOUT output by the output switching circuit 252a-7 changes toward the voltage Vb3.

[0269] That is, the output switching circuit 252a-7 of the modified example of the second embodiment includes a transfer gate tg7-1 having one end supplied with the drive voltage signal VBV3 and the other end electrically connected to the ejection section 600, a transfer gate tg7-2 having one end supplied with the drive voltage signal VBV3 and the other end electrically connected to the ejection section 600, a transfer gate tg7-3 having one end supplied with the drive voltage signal VBV3 and the other end electrically connected to the ejection section 600, and a transfer gate tg7-4 having one end supplied with the drive voltage signal VBV3 and the other end electrically connected to the ejection section 600. Then, the waveform selection control circuit 210 outputs voltage selection signal S17-1, voltage selection signal S17-2, voltage selection signal S17-3, and voltage selection signal S17-4 based on the print data signal SI, so that the conductive state between one end and the other end of transfer gate tg7-1 is controlled by voltage selection signal S17-1, the conductive state between one end and the other end of transfer gate tg7-2 is controlled by voltage selection signal S17-2, the conductive state between one end and the other end of transfer gate tg7-3 is controlled by voltage selection signal S17-3, and the conductive state between one end and the other end of transfer gate tg7-4 is controlled by voltage selection signal S17-4.

[0270] In the liquid ejector 1 of the modified example of the second embodiment configured as described above, the slope of the signal waveform of the drive signal VOUT can be controlled by controlling the time required for a change in the voltage value of the drive signal VOUT output by each of the output switching circuits 252a-1 to 252a-7 of the output circuit 250. Therefore, in addition to the effects of the liquid ejector 1 of the second embodiment described above, the drive signal output circuit 200 can output an optimal waveform of the drive signal VOUT depending on the usage environment of the liquid ejector 1 and the physical properties of the ink used, thereby improving the versatility of the liquid ejector 1.

[0271] Here, the drive signal VOUT[1] is an example of a first drive signal, the drive signal VOUT[2] is an example of a second drive signal, the discharge section 600[1] is an example of a first discharge section, and the discharge section 600[2] is an example of a second discharge section. The piezoelectric element 60 included in the discharge section 600[1] is an example of a first piezoelectric element, and the piezoelectric element 60 included in the discharge section 600[2] is an example of a second piezoelectric element. The drive voltage signal VCV is an example of a first DC voltage signal, the voltage Vc is an example of a first voltage value, any of the drive voltage signals VBV1, VBV2, and VBV3 is an example of a second DC voltage signal, and the corresponding voltages Vb1, Vb2, and Vb3 are examples of second voltage values. Moreover, the waveform selection control circuit 210 of the drive signal output circuit 200 is an example of a selection control circuit, the output switching circuit 252-4 is an example of a first selection circuit, and the corresponding output switching circuits 252-5 to 252-7 are examples of second selection circuits. Moreover, the print data signal SI is an example of an ejection control signal. Moreover, the drive waveform DEP is an example of an ejection waveform, the drive waveform BSD is an example of a micro-vibration waveform, and the drive waveform NVT is an example of a test waveform.

[0272] Although the embodiments and modifications have been described above, the present invention is not limited to these embodiments, and can be embodied in various forms without departing from the spirit of the present invention. For example, the above embodiments can be appropriately combined.

[0273] The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations with the same functions, methods and results, or configurations with the same purpose and effect). The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects as the configurations described in the embodiments or that can achieve the same purpose. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments.

[0274] The following can be derived from the above-described embodiment.

[0275] One aspect of the head unit is a first ejection section including a first piezoelectric element that is driven by a first drive signal and that ejects liquid by driving the first piezoelectric element; A flexible wiring board electrically connected to the first discharge unit; a drive signal output circuit that receives a first DC voltage signal having a first voltage value, a second DC voltage signal having a second voltage value, and an ejection control signal, and outputs the first drive signal; Equipped with The drive signal output circuit is provided on the flexible wiring board, and outputs the first drive signal, which selects or deselects the first DC voltage signal and selects or deselects the second DC voltage signal based on the ejection control signal.

[0276] According to this head unit, the drive signal output circuit can be disposed in the vicinity of the ejection portions, reducing the risk of waveform distortion caused by the impedance of the propagation path occurring in the first drive signal output by the drive signal output circuit.

[0277] In one aspect of the head unit, The drive signal output circuit includes: a first selection circuit that selects or deselects the first DC voltage signal; a second selection circuit that selects or deselects the second DC voltage signal; a waveform information storage circuit in which waveform information of the first drive signal is stored; a selection control circuit that acquires the waveform information and controls the first selection circuit and the second selection circuit based on the acquired waveform information and the ejection control signal; may have the following structure:

[0278] According to this head unit, since the waveform information is stored inside the drive signal output circuit, there is no need to input the waveform information to the head unit from the outside, and the amount of information input to the head unit is reduced, thereby reducing the information transmission load.

[0279] In one aspect of the head unit, a second ejection section including a second piezoelectric element that is driven by a second drive signal and that ejects liquid by driving the second piezoelectric element; the drive signal output circuit outputs the second drive signal by selecting or not selecting the first DC voltage signal and by selecting or not selecting the second DC voltage signal based on the ejection control signal; A propagation distance over which the first drive signal is propagated from the drive signal output circuit to the first ejection section and a propagation distance over which the second drive signal is propagated from the drive signal output circuit to the second ejection section may be substantially equal to each other.

[0280] This head unit reduces the risk of a difference in transmission time occurring between the first drive signal supplied to the first ejection section and the second drive signal supplied to the second ejection section, thereby improving the accuracy of ink ejection from the head unit.

[0281] In one aspect of the head unit, The drive signal output circuit may output the first drive signal including an ejection waveform that drives the first piezoelectric element so as to eject liquid from the first ejection portion.

[0282] In one aspect of the head unit, The drive signal output circuit may output the first drive signal including a micro-vibration waveform that drives the first piezoelectric element so as to prevent liquid from being ejected from the first ejection portion.

[0283] In one aspect of the head unit, The drive signal output circuit may output the first drive signal including a test waveform for testing a state of the first ejection portion.

[0284] One aspect of the liquid ejection device is a first ejection section including a first piezoelectric element that is driven by a first drive signal and that ejects liquid by driving the first piezoelectric element; A flexible wiring board electrically connected to the first discharge unit; a drive signal output circuit that receives a first DC voltage signal having a first voltage value, a second DC voltage signal having a second voltage value, and an ejection control signal, and outputs the first drive signal; A control circuit that outputs the ejection control signal; Equipped with The drive signal output circuit may be provided on the flexible wiring board, and may output the first drive signal that selects or deselects the first DC voltage signal and selects or deselects the second DC voltage signal based on the ejection control signal.

[0285] According to this liquid ejection device, the drive signal output circuit can be disposed in the vicinity of the ejection section, reducing the risk of waveform distortion caused by the impedance of the propagation path occurring in the first drive signal output by the drive signal output circuit.

[0286] In one aspect of the liquid ejection device, The drive signal output circuit includes: a first selection circuit that selects or deselects the first DC voltage signal; a second selection circuit that selects or deselects the second DC voltage signal; a waveform information storage circuit in which waveform information of the first drive signal is stored; a selection control circuit that acquires the waveform information and controls the first selection circuit and the second selection circuit based on the acquired waveform information and the ejection control signal; may have the following structure:

[0287] According to this liquid ejection device, since the waveform information is stored inside the drive signal output circuit, there is no need to input the waveform information to the head unit from the outside, and the amount of information input to the head unit is reduced, thereby reducing the information transmission load.

[0288] In one aspect of the liquid ejection device, a second ejection section including a second piezoelectric element that is driven by a second drive signal and that ejects liquid by driving the second piezoelectric element; the drive signal output circuit outputs the second drive signal by selecting or not selecting the first DC voltage signal and by selecting or not selecting the second DC voltage signal based on the ejection control signal; A propagation distance over which the first drive signal is propagated from the drive signal output circuit to the first ejection section and a propagation distance over which the second drive signal is propagated from the drive signal output circuit to the second ejection section may be substantially equal to each other.

[0289] This liquid ejection device reduces the risk of a difference in transmission time occurring between the first drive signal supplied to the first ejection section and the second drive signal supplied to the second ejection section, thereby improving the accuracy of ejecting ink from the head unit.

[0290] In one aspect of the liquid ejection device, The drive signal output circuit may output the first drive signal including an ejection waveform that drives the first piezoelectric element so as to eject liquid from the first ejection portion.

[0291] In one aspect of the liquid ejection device, The drive signal output circuit may output the first drive signal including a micro-vibration waveform that drives the first piezoelectric element so as to prevent liquid from being ejected from the first ejection portion.

[0292] In one aspect of the liquid ejection device, The drive signal output circuit may output the first drive signal including a test waveform for testing a state of the first ejection portion. [Explanation of symbols]

[0293] 1...liquid ejection device, 5...ink container, 10...control unit, 20...head unit, 21...print head, 40...transport unit, 41...transport motor, 42...transport roller, 50...constant voltage output circuit, 60...piezoelectric element, 100...control circuit, 200...drive signal output circuit, 210...waveform selection control circuit, 212...register, 214...latch circuit, 216...decoder, 230...waveform information storage circuit, 250...output circuit, 252-1 to 252-7, 252a-1 to 252a-7...output switching circuit, 300...head chip, 310...nozzle plate, 320...flow path forming substrate, 330...pressure chamber substrate, 340...protection Substrate, 350... compliance portion, 351... sealing film, 352... support, 360... vibration plate, 370... case, 400... flexible wiring substrate, 410... semiconductor device, 600... ejection portion, 610... ink flow path, 611... liquid inlet, 612... reservoir, 613... pressure chamber, 614... individual flow path, 615... communicating flow path, 616... reservoir, 651... nozzle, P... medium, ci1 to ci6, co2 to co7... constant current circuit, inv1 to inv7... inverter, sw1a to sw6a, sw2a to sw7b... switches, tg1 to tg7... transfer gate, ws2a to ws6a, ws2b to ws7b... switches

Claims

1. a first ejection section including a first piezoelectric element that is driven by a first drive signal and that ejects liquid by driving the first piezoelectric element; A flexible wiring board electrically connected to the first ejection unit; a drive signal output circuit which receives a first DC voltage signal having a first voltage value, a second DC voltage signal having a second voltage value, and an ejection control signal, and outputs the first drive signal; Equipped with the drive signal output circuit is provided on the flexible wiring board, and outputs the first drive signal in which the first DC voltage signal is selected or not selected and the second DC voltage signal is selected or not selected based on the ejection control signal. A head unit characterized by:

2. The drive signal output circuit includes: a first selection circuit that selects or deselects the first DC voltage signal; a second selection circuit that selects or deselects the second DC voltage signal; a waveform information storage circuit in which waveform information of the first drive signal is stored; a selection control circuit that acquires the waveform information and controls the first selection circuit and the second selection circuit based on the acquired waveform information and the ejection control signal; having 2. The head unit according to claim 1.

3. a second ejection section including a second piezoelectric element that is driven by a second drive signal and that ejects liquid by driving the second piezoelectric element; the drive signal output circuit outputs the second drive signal in which the first DC voltage signal is selected or not selected and the second DC voltage signal is selected or not selected based on the ejection control signal; a propagation distance over which the first drive signal is propagated from the drive signal output circuit to the first ejection section and a propagation distance over which the second drive signal is propagated from the drive signal output circuit to the second ejection section are substantially equal to each other.

2. The head unit according to claim 1.

4. the drive signal output circuit outputs the first drive signal including an ejection waveform that drives the first piezoelectric element so as to eject liquid from the first ejection portion.

2. The head unit according to claim 1.

5. the drive signal output circuit outputs the first drive signal including a micro-vibration waveform that drives the first piezoelectric element so as not to eject liquid from the first ejection portion.

2. The head unit according to claim 1.

6. the drive signal output circuit outputs the first drive signal including a test waveform for testing a state of the first ejection section.

2. The head unit according to claim 1.

7. a first ejection section including a first piezoelectric element that is driven by a first drive signal and that ejects liquid by driving the first piezoelectric element; A flexible wiring board electrically connected to the first ejection unit; a drive signal output circuit which receives a first DC voltage signal having a first voltage value, a second DC voltage signal having a second voltage value, and an ejection control signal, and outputs the first drive signal; A control circuit that outputs the ejection control signal; Equipped with the drive signal output circuit is provided on the flexible wiring board, and outputs the first drive signal in which the first DC voltage signal is selected or not selected and the second DC voltage signal is selected or not selected based on the ejection control signal. A liquid ejection device comprising:

8. The drive signal output circuit includes: a first selection circuit that selects or deselects the first DC voltage signal; a second selection circuit that selects or deselects the second DC voltage signal; a waveform information storage circuit in which waveform information of the first drive signal is stored; a selection control circuit that acquires the waveform information and controls the first selection circuit and the second selection circuit based on the acquired waveform information and the ejection control signal; having 8. The liquid ejection device according to claim 7.

9. a second ejection section including a second piezoelectric element that is driven by a second drive signal and that ejects liquid by driving the second piezoelectric element; the drive signal output circuit outputs the second drive signal in which the first DC voltage signal is selected or not selected and the second DC voltage signal is selected or not selected based on the ejection control signal; a propagation distance over which the first drive signal is propagated from the drive signal output circuit to the first ejection section and a propagation distance over which the second drive signal is propagated from the drive signal output circuit to the second ejection section are substantially equal to each other.

8. The liquid ejection device according to claim 7.

10. the drive signal output circuit outputs the first drive signal including an ejection waveform that drives the first piezoelectric element so as to eject liquid from the first ejection portion.

8. The liquid ejection device according to claim 7.

11. the drive signal output circuit outputs the first drive signal including a micro-vibration waveform that drives the first piezoelectric element so as not to eject liquid from the first ejection portion.

8. The liquid ejection device according to claim 7.

12. the drive signal output circuit outputs the first drive signal including a test waveform for testing a state of the first ejection section.

8. The liquid ejection device according to claim 7.

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