Liquid dispensing device

Abstract

To provide a liquid discharge device which can improve a problem to the heat generated in a propagation path in which the heavy current flows.SOLUTION: A liquid discharge device for forming an image on a medium by discharging liquid comprises: a first discharge head which discharges liquid; a first liquid supply part which supplies the liquid to the first discharge head; a first heating element in which at least a portion thereof is brought into contact with the first liquid supply part; a wiring board which includes a first surface, a second surface different from the first surface and first propagation wiring in which the first drive current supplied from the first heating element propagates; and a first temperature-indicating part which is provided on the first surface. The first temperature-indicating part indicates that the temperature of the first temperature-indicating part is less than a first threshold in the first state, and indicates that the temperature of the first temperature-indicating part is equal to or greater than the first threshold in the second state. The first state and the second state reversibly change. At least a portion of the first temperature-indicating part overlaps at least a portion of the first propagation wiring in the normal direction of the wiring board.SELECTED DRAWING: Figure 17

Description

[Technical Field]

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

[0002] For liquid ejection devices that eject liquid such as ink onto a medium, a technique is known that adjusts the temperature of the ink to control the viscosity of the ejected ink and enable stable ejection characteristics. For example, Patent Document 1 discloses a technique that enables stable ink ejection in a liquid ejection device that is capable of ejecting multiple types of ink by individually adjusting the temperature of the ink for each type of ink. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-182291 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a liquid ejection device 1 having a heating element (heat exchange mechanism) for adjusting the temperature of ink as described in Patent Document 1, in which a large current is supplied to the heating element, heat generation also increases in the propagation path through which the large current flows. The technology described in Patent Document 1 is insufficient for dealing with the heat generated in the propagation path through which this large current flows, and there is room for improvement. [Means for solving the problem]

[0005] One aspect of the liquid ejection device according to the present invention is A liquid ejection device that forms an image on a medium by ejecting a liquid, a first ejection head that ejects liquid; a first liquid supply unit that supplies liquid to the first ejection head; a first heating element at least a portion of which is in contact with the first liquid supply unit; a wiring substrate including a first surface, a second surface different from the first surface, and a first propagation wiring through which a first drive current supplied to the first heating element propagates; a first temperature indicating portion provided on the first surface; Equipped with the first temperature indicator indicates that the temperature of the first temperature indicator is less than a first threshold value in a first state, and indicates that the temperature of the first temperature indicator is equal to or greater than the first threshold value in a second state, and the first state and the second state change reversibly; At least a portion of the first temperature indicator overlaps with at least a portion of the first propagation wire in the normal direction of the wiring substrate. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 2 is a diagram illustrating a functional configuration of the liquid ejection device. [Figure 2] FIG. 2 is a diagram illustrating a schematic structure of a discharge section. [Figure 3] 4A and 4B are diagrams showing examples of signal waveforms of drive signals COMA and COMB. [Figure 4] FIG. 4 is a diagram showing an example of the waveform of a drive signal VOUT. [Figure 5] FIG. 2 is a diagram illustrating a configuration of a drive signal selection circuit. [Figure 6] FIG. 10 is a diagram showing an example of the decoded content in the decoder. [Figure 7] FIG. 2 is a diagram illustrating a configuration of a selection circuit. [Figure 8] 10A and 10B are diagrams for explaining the operation of a drive signal selection circuit. [Figure 9] 2A and 2B are diagrams illustrating the structure of the liquid ejection device when viewed from the side. [Figure 10] FIG. 2 is a side view showing the structure of a printing unit of the liquid ejection device. [Figure 11] FIG. 2 is a front view showing the structure of a printing unit of the liquid ejection device. [Figure 12] FIG. 2 is a perspective view showing the structure of a printing unit of the liquid ejection device. [Figure 13] FIG. 2 is a diagram showing an example of a cross-sectional structure of a heating control board. [Figure 14] FIG. 2 is a diagram showing an example of a wiring pattern provided on a layer 231. [Figure 15] FIG. 10 is a diagram showing an example of a wiring pattern provided on a layer 232. [Figure 16] FIG. 10 is a diagram showing an example of a wiring pattern provided on a layer 233. [Figure 17] FIG. 2 is a diagram showing an example of the configuration of a surface 211 of a heating control board. DETAILED DESCRIPTION OF THE INVENTION

[0007] Preferred embodiments of the present invention will be described below with reference to the drawings. The drawings used are for the convenience of explanation. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0008] The liquid ejection device according to the present invention is a printing device that ejects ink onto a recording medium as an example of a liquid, and will be described using a so-called inkjet printer as an example. However, the liquid ejection device is not limited to an inkjet printer, and may be, for example, a liquid ejection device that ejects color materials used in the manufacture of color filters for liquid crystal displays and the like, a liquid ejection device that ejects electrode materials used in the formation of electrodes for organic electroluminescence displays, surface-emitting displays, and the like, or a liquid ejection device that ejects bioorganic substances used in the manufacture of biochips.

[0009] 1. Functional configuration of the liquid ejection device FIG. 1 is a diagram showing the functional configuration of a liquid ejection device 1. The liquid ejection device 1 in this embodiment is a so-called serial inkjet printer that transports a recording medium on which an image is to be formed along a transport direction, and a carriage carrying a liquid ejection head 400 that ejects ink onto the recording medium moves back and forth along a main scanning direction that intersects with the transport direction, thereby forming a desired image on the recording medium. The liquid ejection device 1 of this embodiment will be described as a so-called textile printer that uses a cloth as the recording medium and forms a desired image on the cloth. The recording medium used in the liquid ejection device 1 is not limited to a cloth, and may be, for example, paper, etc.

[0010] As shown in FIG. 1, the liquid ejection device 1 includes a control unit 10 and a head unit 20.

[0011] The control unit 10 includes a main control circuit 100 and a power supply circuit 101. The control unit 10 controls the operation of the head unit 20.

[0012] A specific example of the operation of the control unit 10 will be described. An image signal PDATA is input to the main control circuit 100 from an external device such as a host computer (not shown). The main control circuit 100 performs various signal processing such as image processing on the input image signal PDATA. The main control circuit 100 then outputs a transmission signal Tx including the processed signal to the head unit 20.

[0013] In addition, the main control circuit 100 generates various control signals that control each part of the liquid ejection device 1, such as a control signal that controls the transport of the recording medium along the transport direction and a control signal that controls the movement of the carriage along the main scanning direction, which will be described later, and outputs them to the corresponding components.

[0014] The power supply circuit 101 is supplied with a commercial AC voltage AC from a commercial power source (not shown). The power supply circuit 101 generates a voltage signal VHC of a predetermined voltage value by AC / DC converting the supplied commercial AC voltage AC. This voltage signal VHC is, for example, a DC voltage of 24 V, and is supplied to the head unit 20. The power supply circuit 101 may also generate DC voltages of voltage values ​​such as 42 V, 7.5 V, 5 V, and 3.3 V from the supplied commercial AC voltage AC. The various DC voltages generated by the power supply circuit 101 are used as power supply voltages for each component of the liquid ejection device 1. That is, the power supply circuit 101 generates DC voltages used as power supply voltages for each component of the liquid ejection device 1 from the commercial AC voltage AC supplied to the liquid ejection device 1, and supplies the DC voltages to each part of the liquid ejection device 1. The power supply circuit 101 may have multiple AC / DC conversion circuits that generate various DC voltages, and may generate DC voltages of multiple voltage values ​​by converting the voltage value of a DC voltage generated by one AC / DC conversion using a DC / DC conversion circuit. Hereinafter, the current that flows based on the voltage signal VHC output by the power supply circuit 101 may be referred to as the heating current Ihc. In other words, the liquid ejection device 1 includes a power supply circuit 101 that outputs the heating current Ihc.

[0015] As described above, the control unit 10 generates the transmission signal Tx and the voltage signal VHC based on the image signal PDATA and the commercial AC voltage AC, and outputs them to each part of the liquid ejection device 1, including the head unit 20. In this way, the control unit 10 controls the operation of the head unit 20.

[0016] The head unit 20 includes a discharge control circuit 200, drive circuits 300-1 to 300-n, liquid discharge heads 400-1 to 400-n, a temperature control circuit 500, ink heaters 700-1 to 700-m, and switches SW-1 to SW-m. The head unit 20 controls the discharge timing and amount of ink discharged based on a transmission signal Tx output by the control unit 10. This allows a desired image to be formed on a recording medium.

[0017] Here, the drive circuits 300-1 to 300-n all have the same configuration and are simply referred to as drive circuits 300 when there is no need to distinguish them; the liquid ejection heads 400-1 to 400-n all have the same configuration and are simply referred to as liquid ejection heads 400 when there is no need to distinguish them; the ink heating units 700-1 to 700-m all have the same configuration and are simply referred to as ink heating units 700 when there is no need to distinguish them; and the switches SW-1 to SW-m all have the same configuration and are simply referred to as switches SW when there is no need to distinguish them.

[0018] A specific example of the operation of the head unit 20 will be described. The transmission signal Tx is input to the discharge control circuit 200 included in the head unit 20. When the transmission signal Tx is input, the discharge control circuit 200 generates a reception signal Rx indicating that the transmission signal Tx has been received, and outputs the reception signal Rx to the main control circuit 100. From the viewpoint of enabling high-speed communication with the control unit 10, the transmission signal Tx and reception signal Rx can use differential signals of the LVDS (Low Voltage Differential Signaling) system. Furthermore, the transmission signal Tx and reception signal Rx are not limited to electrical signals and may be optical signals, or electrical signals and optical signals may be used in combination.

[0019] Furthermore, the discharge control circuit 200 generates a clock signal SCK, print data signals SI1 to SIn, latch signals LAT1 to LATn, change signals CH1 to CHn, and basic drive signals dA1 to dAn, dB1 to dBn based on the input transmission signal Tx.

[0020] The basic drive signals dA1 to dAn and dB1 to dBn output by the discharge control circuit 200 are input to the drive circuits 300-1 to 300-n.

[0021] The drive circuit 300-1 includes a drive signal output circuit 310 and a reference voltage signal output circuit 320. The reference drive signals dA1 and dB1 output by the discharge control circuit 200 are input to the drive signal output circuit 310 of the drive circuit 300-1. The drive signal output circuit 310 performs digital-to-analog conversion on the input reference drive signal dA1 and then class-D amplifies the converted analog signal to generate the drive signal COMA1. The drive signal output circuit 310 also performs digital-to-analog conversion on the input reference drive signal dB1 and then class-D amplifies the converted analog signal to generate the drive signal COMB1. That is, the drive signal output circuit 310 includes two class-D amplifier circuits: one that generates the drive signal COMA1 based on the reference drive signal dA1, and the other that generates the drive signal COMB1 based on the reference drive signal dB1. The drive signal output circuit 310 included in the drive circuit 300 outputs the generated drive signals COMA1 and COMB1 to the liquid ejection head 400-1. Such a drive signal output circuit 310 may include a class A amplifier circuit, a class B amplifier circuit, or a class AB amplifier circuit instead of or in addition to the class D amplifier circuit.

[0022] Furthermore, the reference voltage signal output circuit 320 included in the drive circuit 300-1 generates a reference voltage signal VBS1 and outputs it to the liquid ejection head 400-1. The reference voltage signal VBS1 may be, for example, a signal of ground potential, or a DC voltage signal with a voltage value of 5.5 V or 6 V.

[0023] As mentioned above, the drive circuits 300-1 to 300-n all have the same configuration. In the following explanation, it is assumed that basic drive signals dAi and dBi are input to drive circuit 300-i (i = 1 to n), and drive circuit 300-i generates drive signals COMAi and COMBi and a reference voltage signal VBSi and outputs them to liquid ejection head 400-i.

[0024] The liquid ejection heads 400-1 to 400-n include piezoelectric elements 60 that are driven based on drive signals COMA1 to COMAn and COMB1 to COMBn, and the driving of the piezoelectric elements 60 ejects ink onto a recording medium.

[0025] The liquid ejection head 400-1 has a drive signal selection circuit 420 and p ejection units 600. The liquid ejection head 400-1 receives the clock signal SCK, print data signal SI1, latch signal LAT1, and change signal CH1 output by the ejection control circuit 200, and the drive signals COMA1, COMB1, and reference voltage signal VBS1 output by the drive circuit 300-1. The liquid ejection head 400-1 switches whether to supply the drive signals COMA1, COMB1 to the piezoelectric elements 60 at a timing determined by the input clock signal SCK, print data signal SI1, latch signal LAT1, and change signal CH1. This controls the drive of the piezoelectric elements 60, and the amount of ink ejected from the ejection units 600 including the piezoelectric elements 60.

[0026] Specifically, the drive signal selection circuit 420 of the liquid ejection head 400-1 is configured to include, for example, an integrated circuit device. The drive signal selection circuit 420 of the liquid ejection head 400-1 receives a print data signal SI1, a latch signal LAT1, a change signal CH1, a clock signal SCK, and drive signals COMA1 and COMB1. The drive signal selection circuit 420 generates a drive signal VOUT by selecting or deselecting the drive signals COMA1 and COMB1 in accordance with the print data signal SI1 at a timing determined by the latch signal LAT1 and the change signal CH1. The drive signal VOUT generated by the drive signal selection circuit 420 is supplied to the p ejection units 600 of the liquid ejection head 400-1.

[0027] Each of the p ejection sections 600 included in the liquid ejection head 400-1 includes a piezoelectric element 60. A drive signal VOUT output by the drive signal selection circuit 420 is supplied to one end of the piezoelectric element 60 included in each of the p ejection sections 600. A reference voltage signal VBS1 output by the reference voltage signal output circuit 320 of the drive circuit 300-1 is supplied to the other end of the piezoelectric element 60 included in each of the p ejection sections 600. The piezoelectric element 60 included in each of the ejection sections 600 is driven in response to the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBS1 supplied to the other end. An amount of ink corresponding to the drive of this piezoelectric element 60 is ejected from the corresponding ejection section 600.

[0028] As described above, the liquid ejection heads 400-1 to 400-n all have the same configuration. Specifically, the liquid ejection head 400-i receives a print data signal SIi, a latch signal LATi, a change signal CHi, a clock signal SCK, and drive signals COMAi and COMBi. The drive signal selection circuit 420 of the liquid ejection head 400-i generates a drive signal VOUT by selecting or deselecting the drive signals COMAi and COMBi based on the print data signal SIi, the latch signal LATi, the change signal CHi, and the clock signal SCK. The drive signal VOUT generated by the drive signal selection circuit 420 of the liquid ejection head 400-i is supplied to one end of the piezoelectric element 60 included in each of the p ejection sections 600 of the liquid ejection head 400-i. A reference voltage signal VBSi is supplied to the other end of the piezoelectric element 60 included in each of the p ejection sections 600 of the liquid ejection head 400-i. Then, the piezoelectric elements 60 included in the p ejection sections 600 of the liquid ejection head 400-i are driven based on the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBSi supplied to the other end, and an amount of ink corresponding to the drive is ejected from the corresponding ejection section 600.

[0029] Each of the ink heating units 700-1 to 700-m includes a heating unit 710 and a temperature detection unit 720.

[0030] A voltage signal VHC is supplied to the heating unit 710 of the ink heating unit 700-1 via the switch SW-1. That is, a heating current Ihc-1 out of the heating current Ihc based on the voltage signal VHC output by the power supply circuit 101 is supplied to the heating unit 710 of the ink heating unit 700-1 via the switch SW-1. As a result, the heating unit 710 of the ink heating unit 700-1 generates heat due to the heating current Ihc-1. A temperature detection unit 720 of the ink heating unit 700-1 detects the temperature of the heating unit 710 of the ink heating unit 700-1 and outputs it to the temperature control circuit 500 as a temperature detection signal Tmp-1.

[0031] Similarly, the heating unit 710 of the ink heating unit 700-j (j = 1 to m) is supplied with a heating current Ihc-j from the heating current Ihc based on the voltage signal VHC output by the power supply circuit 101 via the switch SW-j. As a result, the heating unit 710 of the ink heating unit 700-j generates heat due to the heating current Ihc-j. The temperature detection unit 720 of the ink heating unit 700-j detects the temperature of the heating unit 710 of the ink heating unit 700-j and outputs it to the temperature control circuit 500 as a temperature detection signal Tmp-j.

[0032] Temperature detection signals Tmp-1 to Tmp-m output by the temperature detection units 720 of the ink heating units 700-1 to 700-m, respectively, are input to the temperature control circuit 500. Based on the input temperature detection signals Tmp-1 to Tmp-m, the temperature control circuit 500 generates switch control signals Sc-1 to Sc-m for controlling the switches SW-1 to SW-m, respectively, and outputs them to the corresponding switches SW-1 to SW-m.

[0033] Specifically, the temperature control circuit 500 detects the temperature of the heating unit 710 of the ink heating unit 700-1 based on the temperature detection signal Tmp-1 output by the temperature detection unit 720 of the ink heating unit 700-1. If the temperature of the heating unit 710 of the ink heating unit 700-1 is lower than the expected temperature, the temperature control circuit 500 generates a switch control signal Sc-1 to control the switch SW-1 so as to increase the amount of heating current Ihc-1 flowing through the switch SW-1, and outputs the signal to the switch SW-1. On the other hand, if the temperature of the heating unit 710 of the ink heating unit 700-1 is higher than the expected temperature, the temperature control circuit 500 generates a switch control signal Sc-1 to control the switch SW-1 so as to decrease the amount of heating current Ihc-1 flowing through the switch SW-1, and outputs the signal to the switch SW-1. This controls the temperature of the heating unit 710 of the ink heating unit 700-1.

[0034] Similarly, the temperature control circuit 500 detects the temperature of the heating unit 710 of the ink heating unit 700-j based on the temperature detection signal Tmp-j output by the temperature detection unit 720 of the ink heating unit 700-j. If the temperature of the heating unit 710 of the ink heating unit 700-j is lower than the expected temperature, the temperature control circuit 500 generates a switch control signal Sc-j to control the switch SW-j so as to increase the amount of heating current Ihc-j flowing through the switch SW-j, and outputs the signal to the switch SW-j. On the other hand, if the temperature of the heating unit 710 of the ink heating unit 700-j is higher than the expected temperature, the temperature control circuit 500 generates a switch control signal Sc-j to control the switch SW-j so as to decrease the amount of heating current Ihc-j flowing through the switch SW-j, and outputs the signal to the switch SW-j. This controls the temperature of the heating unit 710 of the ink heating unit 700-j to a predetermined value.

[0035] Here, the switches SW-1 to SW-m may be bipolar transistors that can control the conduction state between the collector terminal and the emitter terminal according to the amount of current supplied to the base terminal, or MOSFETs that can control the conduction state between the drain terminal and the source terminal according to the amount of current supplied to the gate terminal.

[0036] In the following description, it is assumed that the temperature detection unit 720 of the ink heating unit 700 outputs a temperature detection signal Tmp to the temperature control circuit 500 as a result of detecting the temperature of the heating unit 710 of the ink heating unit 700. That is, in the following description, when there is no need to distinguish between the temperature detection signals Tmp-1 to Tmp-m, they may be referred to as the temperature detection signal Tmp.

[0037] As described above, in the liquid ejection device 1 of this embodiment, the control unit 10 controls the transportation of the recording medium in accordance with the input image signal PDATA, and also generates a transmission signal Tx and outputs it to the head unit 20. Then, the head unit 20 controls the ejection of ink from the liquid ejection heads 400-1 to 400-n based on the transmission signal Tx. As a result, a predetermined amount of ink lands at a desired position on the recording medium, forming a desired dot on the recording medium.

[0038] Furthermore, in the liquid ejection device 1 of this embodiment, the head unit 20 has a temperature control circuit 500 for controlling the temperature of the ink, and ink heating units 700-1 to 700-m. The physical properties of the ink used in the liquid ejection device 1, such as viscosity, may change depending on the temperature. In the liquid ejection device 1 of this embodiment, the temperature control circuit 500 and the ink heating units 700-1 to 700-m make it possible to maintain a substantially constant temperature for the ink flowing inside the liquid ejection device 1. This stabilizes the physical properties, such as viscosity, of the ink flowing inside the liquid ejection device 1, and as a result, the ink ejection accuracy in the liquid ejection device 1 can be improved.

[0039] 2. Configuration and operation of liquid ejection head Next, we will explain the configuration of the liquid ejection head 400. Here, in explaining the configuration of the liquid ejection head 400, we will assume that the following are input to the liquid ejection head 400: a print data signal SI of the print data signals SI1 to SIn, a latch signal LAT of the latch signals LAT1 to LATn, a change signal CH of the change signals CH1 to CHn, a clock signal SCK, a drive signal COMA of the drive signals COMA1 to COMAn, a drive signal COMB of the drive signals COMB1 to COMBn, and a reference voltage signal VBS of the reference voltage signals VBS1 to VBSn.

[0040] First, the structure of the p ejection units 600 of the liquid ejection head 400 will be described. Fig. 2 is a diagram for explaining the schematic structure of one of the p ejection units 600. In addition to the ejection unit 600, Fig. 2 also illustrates a reservoir 641 and a supply port 661.

[0041] 2, the ejection section 600 includes a piezoelectric element 60, a vibration plate 621, a cavity 631, and a nozzle plate 632. The piezoelectric element 60 includes a piezoelectric body 601 and electrodes 611 and 612. The piezoelectric element 60 is configured such that the electrodes 611 and 612 are positioned to sandwich the piezoelectric body 601. The piezoelectric element 60 configured as described above is driven so that the central portion is displaced in the vertical direction in response to the potential difference between the voltage supplied to the electrode 611 and the voltage supplied to the electrode 612.

[0042] Specifically, a drive signal VOUT based on the drive signals COMA and COMB is supplied to electrode 611 of piezoelectric element 60, and a reference voltage signal VBS is supplied to electrode 612 of piezoelectric element 60. As the voltage value of drive signal VOUT supplied to electrode 611 changes, the potential difference between electrode 611 to which drive signal VOUT is supplied and electrode 612 to which reference voltage signal VBS is supplied changes. As a result, piezoelectric element 60 is driven so that the central portion is displaced in the up and down directions.

[0043] The diaphragm 621 is located below the piezoelectric element 60 in Fig. 2. In other words, the piezoelectric element 60 is formed on the upper surface of the diaphragm 621 in Fig. 2. Such a diaphragm 621 deforms in the vertical direction as the piezoelectric element 60 is driven in the vertical direction.

[0044] A cavity 631 is located below the diaphragm 621 in FIG. 2. Ink is supplied to the cavity 631 from a reservoir 641 provided in common to the plurality of ejection units 600. Ink stored in an ink container (not shown) is introduced into the reservoir 641 via a supply port 661. That is, the ink stored in the ink container is branched at the reservoir 641 and supplied to the interior of the cavity 631. In this way, the interior of the cavity 631 is filled with ink. The internal volume of the cavity 631 expands or contracts in accordance with the vertical displacement of the diaphragm 621. That is, the diaphragm 621 functions as a diaphragm that changes the internal volume of the cavity 631, and the cavity 631 functions as a pressure chamber whose pressure changes in accordance with the vertical displacement of the diaphragm 621.

[0045] Nozzles 651 are formed in the nozzle plate 632. That is, the ejection section 600 includes the nozzles 651. The nozzles 651 are openings provided in the nozzle plate 632 and communicate with the cavities 631. When the internal volume of the cavities 631 changes, ink filled inside the cavities 631 is ejected from the nozzles 651 in accordance with the change in the internal volume.

[0046] In the ejection section 600 configured as described above, when the piezoelectric element 60 is driven to bend upward, the vibration plate 621 is displaced upward. This causes the internal volume of the cavity 631 to expand, and as a result, ink stored in the reservoir 641 is drawn into the cavity 631. On the other hand, when the piezoelectric element 60 is driven to bend downward, the vibration plate 621 is displaced downward. This causes the internal volume of the cavity 631 to contract, and as a result, an amount of ink corresponding to the degree of contraction of the internal volume of the cavity 631 is ejected from the nozzle 651.

[0047] The piezoelectric element 60 is driven by the supply of a drive signal VOUT corresponding to the drive signals COMA and COMB, and is not limited to the structure shown in FIG. 2 as long as it has a structure that allows ink to be ejected from the nozzle 651 when driven.

[0048] Next, an example of the signal waveforms of the drive signals COMA and COMB output by the drive signal output circuit 310 and an example of the signal waveform of the drive signal VOUT output by the drive signal selection circuit 420 based on the drive signals COMA and COMB will be described.

[0049] 3 is a diagram showing an example of the signal waveforms of the drive signals COMA and COMB. As shown in FIG. 3, the drive signal COMA includes a trapezoidal waveform Adp1 that is placed during a period T1 from when the latch signal LAT rises until when the change signal CH rises, and a trapezoidal waveform Adp2 that is placed during a period T2 from when the change signal CH rises until when the latch signal LAT rises. When the trapezoidal waveform Adp1 is supplied to one end of the piezoelectric element 60, a predetermined amount of ink is ejected from the ejection section 600 corresponding to that piezoelectric element 60, and when the trapezoidal waveform Adp2 is supplied to one end of the piezoelectric element 60, an amount of ink greater than the predetermined amount is ejected from the ejection section 600 corresponding to that piezoelectric element 60.

[0050] The drive signal COMB includes a trapezoidal waveform Bdp1 arranged in period T1 and a trapezoidal waveform Bdp2 arranged in period T2. When the trapezoidal waveform Bdp1 is supplied to one end of a piezoelectric element 60, ink is not ejected from the ejection section 600 corresponding to that piezoelectric element 60. This trapezoidal waveform Bdp1 is a signal waveform that vibrates the ink near the nozzle opening of the ejection section 600, thereby preventing an increase in ink viscosity. When the trapezoidal waveform Bdp2 is supplied to one end of the piezoelectric element 60, a predetermined amount of ink is ejected from the ejection section 600 corresponding to that piezoelectric element 60, just as when the trapezoidal waveform Adp1 is supplied.

[0051] Here, the trapezoidal waveforms Adp1, Adp2, Bdp1, and Bdp2 are signal waveforms that all have a common voltage Vc at their start and end times, i.e., each of the trapezoidal waveforms Adp1, Adp2, Bdp1, and Bdp2 starts and ends at voltage Vc.

[0052] In the following description, when the trapezoidal waveform Adp1 is supplied to one end of the piezoelectric element 60 and when the trapezoidal waveform Bdp2 is supplied to one end of the piezoelectric element 60, a predetermined amount of ink ejected from the ejection section 600 corresponding to that piezoelectric element 60 will be referred to as a small amount, and when the trapezoidal waveform Adp2 is supplied to one end of the piezoelectric element 60, a larger amount of ink than the predetermined amount ejected from the ejection section 600 corresponding to that piezoelectric element 60 will be referred to as a medium amount. Also, when the trapezoidal waveform Bdp1 is supplied to one end of the piezoelectric element 60, the operation of vibrating the ink near the nozzle opening of the ejection section 600 corresponding to that piezoelectric element 60 to prevent an increase in ink viscosity will be referred to as micro-vibration BSD.

[0053] 3 illustrates a case where the trapezoidal waveform Adp1 and the trapezoidal waveform Bdp2 have the same signal waveform shape, but the trapezoidal waveform Adp1 and the trapezoidal waveform Bdp2 may have different signal waveform shapes. In the following description, it is assumed that when the trapezoidal waveform Adp1 is supplied to the piezoelectric element 60 and when the trapezoidal waveform Bdp2 is supplied to the piezoelectric element 60, a small amount of ink is ejected from the corresponding ejection section 600, but this is not limited to this. In other words, the signal waveforms of the drive signals COMA and COMB are not limited to the signal waveform shapes shown in FIG. 3, and various combinations of waveforms may be used depending on the properties of the ink to be ejected, the material of the recording medium, etc.

[0054] Furthermore, the drive circuits 300-1 to 300-n may output signal waveforms of different shapes. That is, the drive signals COMA1 to COMAn may include signal waveforms that are different from one another, and the drive signals COMB1 to COMBn may include signal waveforms that are different from one another.

[0055] FIG. 4 is a diagram showing an example of the waveform of the drive signal VOUT corresponding to each of the "large dots LD," "medium dots MD," "small dots SD," and "micro vibrations BSD" formed on the recording medium.

[0056] 4, the drive signal VOUT for forming a "large dot LD" on the recording medium has a signal waveform formed by successively supplying a trapezoidal waveform Adp1 arranged in period T1 and a trapezoidal waveform Adp2 arranged in period T2. When this drive signal VOUT is supplied to one end of a piezoelectric element 60, a small amount of ink and a medium amount of ink are ejected from the ejection section 600 corresponding to that piezoelectric element 60. Then, the respective ink droplets land on the recording medium and combine to form a large dot LD on the recording medium.

[0057] The drive signal VOUT for forming a "medium dot MD" on the recording medium has a signal waveform that is a succession of a trapezoidal waveform Adp1 arranged in period T1 and a trapezoidal waveform Bdp2 arranged in period T2. When this drive signal VOUT is supplied to one end of a piezoelectric element 60, a small amount of ink is ejected twice from the ejection section 600 corresponding to that piezoelectric element 60. Then, each ink droplet lands on the recording medium and combines to form a medium dot MD that is smaller than a large dot LD on the recording medium.

[0058] The drive signal VOUT for forming a "small dot SD" on the recording medium is a signal waveform that successively includes a trapezoidal waveform Adp1 during period T1 and a waveform with a constant voltage Vc during period T2. When this drive signal VOUT is supplied to one end of a piezoelectric element 60, a small amount of ink is ejected once from the ejection section 600 corresponding to that piezoelectric element 60. When the ejected ink lands on the recording medium, a small dot SD that is smaller than a medium dot MD is formed on the recording medium.

[0059] The drive signal VOUT corresponding to the "micro vibration BSD" has a signal waveform consisting of a succession of a trapezoidal waveform Bdp1 during period T1 and a waveform with a constant voltage Vc during period T2. When this drive signal VOUT is supplied to one end of the piezoelectric element 60, only the ink near the nozzle opening of the ejection unit 600 corresponding to that piezoelectric element 60 vibrates, and no ink is ejected from the ejection unit 600. Therefore, no ink lands on the recording medium, and no dots are formed on the recording medium.

[0060] Here, the waveform in which the voltage value contained in the drive signal VOUT is constant at voltage Vc includes a waveform in which the voltage value that was previously supplied to the piezoelectric element 60 is constant at voltage Vc and is maintained by the capacitive component of the piezoelectric element 60 when the drive signal selection circuit 420 does not select any of the trapezoidal waveforms Adp1, Adp2, Bdp1, or Bdp2 as the drive signal VOUT.

[0061] As described above, the liquid ejection device 1 of this embodiment forms dots on the recording medium by combining the ink ejected during the period T1 and the ink ejected during the period T2 in the cycle T. The cycle T including the periods T1 and T2 corresponds to the dot formation cycle for forming dots on the recording medium.

[0062] Next, a description will be given of the configuration and operation of the drive signal selection circuit 420, which outputs the drive signal VOUT shown in Fig. 4 by selecting or deselecting the drive signals COMA and COMB. Fig. 5 is a diagram showing the configuration of the drive signal selection circuit 420. As shown in Fig. 5, the drive signal selection circuit 420 has a selection control circuit 430 and p selection circuits 440.

[0063] The selection control circuit 430 receives the print data signal SI, latch signal LAT, change signal CH, and clock signal SCK output by the ejection control circuit 200. The selection control circuit 430 also includes a set of a shift register (S / R) 432, a latch circuit 434, and a decoder 436, each set corresponding to one of the p ejection units 600. That is, the drive signal selection circuit 420 includes p shift registers 432, p latch circuits 434, and p decoders 436.

[0064] The print data signal SI is input to the selection control circuit 430 in synchronization with the clock signal SCK. The print data signal SI also includes 2-bit print data [SIH, SIL] for selecting one of "large dot LD," "medium dot MD," "small dot SD," and "fine vibration BSD," which are serially transmitted to each of the p ejection units 600. In other words, the print data signal SI is a 2p-bit signal. The print data [SIH, SIL] included in the print data signal SI is held in p shift registers 432 corresponding to the p ejection units 600. Specifically, p shift registers 432 corresponding to the ejection units 600 are cascaded, and the serially input print data signal SI is sequentially transferred to the subsequent shift registers 432 of the p cascaded shift registers 432 in accordance with the clock signal SCK. When the print data [SIH, SIL] is held in the corresponding shift register 432, the clock signal SCK stops. In other words, when the supply of the clock signal SCK is stopped, the print data [SIH, SIL] included in the print data signal SI is held in the corresponding shift register 432. In order to distinguish between the shift registers 432 in Fig. 5, the shift registers 432 are denoted as stage 1, stage 2, ..., stage p in order from the upstream side where the print data signal SI is input.

[0065] Each of the p latch circuits 434 simultaneously latches the print data [SIH, SIL] held in each of the p shift registers 432 at the rising edge of the latch signal LAT. The print data [SIH, SIL] latched by the latch circuit 434 is input to the corresponding decoder 436. FIG. 6 is a diagram showing an example of the decoded content in the decoder 436. The decoder 436 outputs selection signals S1 and S2 with logic levels corresponding to the print data [SIH, SIL] latched during periods T1 and T2, respectively. For example, when the input print data [SIH, SIL] = [1, 0], the decoder 436 outputs the selection signal S1 as a high-level logic signal during periods T1 and T2, and the selection signal S2 as a low-level logic signal during periods T1 and T2.

[0066] The selection signals S1 and S2 output by the decoder 436 are input to a selection circuit 440. A selection circuit 440 is provided corresponding to each of the p discharge units 600. That is, the drive signal selection circuit 420 has p selection circuits 440, the same number as the p discharge units 600. FIG. 7 is a diagram showing the configuration of a selection circuit 440 corresponding to one discharge unit 600. As shown in FIG. 7, the selection circuit 440 includes inverters 442a and 442b, which are NOT circuits, and transfer gates 444a and 444b.

[0067] The selection signal S1 is input to the positive control terminal (not marked with a circle) of the transfer gate 444a, and after its logical level is inverted by the inverter 442a, is also input to the negative control terminal (marked with a circle) of the transfer gate 444a. The drive signal COMA is supplied to the input terminal of the transfer gate 444a. When the logical level of the selection signal S1 is H level, the transfer gate 444a establishes electrical continuity between its input terminal and output terminal, and when the logical level of the selection signal S1 is L level, the transfer gate 444a establishes electrical continuity between its input terminal and output terminal. That is, when the logical level of the selection signal S1 is H level, the transfer gate 444a outputs the signal waveform included in the drive signal COMA from its output terminal, and when the logical level of the selection signal S1 is L level, the transfer gate 444a does not output the signal waveform included in the drive signal COMA from its output terminal.

[0068] The selection signal S2 is input to the positive control terminal (not marked with a circle) of the transfer gate 444b, and after its logical level is inverted by the inverter 442b, is also input to the negative control terminal (marked with a circle) of the transfer gate 444b. The drive signal COMB is also supplied to the input terminal of the transfer gate 444b. When the logical level of the selection signal S2 is H level, the transfer gate 444b establishes electrical continuity between its input terminal and output terminal, and when the logical level of the selection signal S2 is L level, the transfer gate 444b establishes electrical continuity between its input terminal and output terminal. That is, when the logical level of the selection signal S2 is H level, the transfer gate 444b outputs the signal waveform included in the drive signal COMB from its output terminal, and when the logical level of the selection signal S2 is L level, the transfer gate 444b does not output the signal waveform included in the drive signal COMB from its output terminal.

[0069] The output terminals of the transfer gates 444a and 444b configured as described above are commonly connected in the selection circuit 440. The drive signal selection circuit 420 outputs the signal at the output terminals of the transfer gates 444a and 444b commonly connected in the selection circuit 440 as the drive signal VOUT.

[0070] The operation of the drive signal selection circuit 420 will now be described with reference to FIG. 8. FIG. 8 is a diagram for explaining the operation of the drive signal selection circuit 420. The print data signal SI is input serially in synchronization with the clock signal SCK. The print data signal SI is then transferred sequentially in synchronization with the clock signal SCK through p shift registers 432 corresponding to the p ejection units 600. Thereafter, when the input of the clock signal SCK stops, the shift register 432 holds the print data [SIH, SIL] corresponding to each of the p ejection units 600. The print data signal SI is input in the order corresponding to the pth, ..., 2nd, and 1st stages of the shift register 432 ejection units 600.

[0071] Then, when the latch signal LAT rises, the latch circuits 434 simultaneously latch the print data [SIH, SIL] held in the shift register 432. Note that LT1, LT2, ..., LTp shown in Fig. 8 indicate the print data [SIH, SIL] latched by the latch circuits 434 corresponding to the first-stage, second-stage, ..., pth-stage shift registers 432.

[0072] The decoder 436 outputs the logic levels of the selection signals S1 and S2 during each of the periods T1 and T2, as shown in Fig. 6, in accordance with the dot size defined by the latched print data [SIH, SIL]. The selection circuit 440 then selects or deselects the signal waveforms included in the drive signals COMA and COMB in accordance with the logic levels of the selection signals S1 and S2 output by the decoder 436, thereby generating the drive signal VOUT.

[0073] Specifically, when print data [SIH,SIL]=[1,1] is input to decoder 436, decoder 436 sets the logic level of selection signal S1 to H,H level during periods T1 and T2, and sets the logic level of selection signal S2 to L,L level during periods T1 and T2. This causes selection circuit 440 to select trapezoidal waveform Adp1 during period T1, and trapezoidal waveform Adp2 during period T2. As a result, drive signal selection circuit 420 outputs drive signal VOUT corresponding to the "large dot LD" shown in FIG. 4.

[0074] Furthermore, when print data [SIH,SIL]=[1,0] is input to decoder 436, decoder 436 sets the logic level of selection signal S1 to H and L levels during periods T1 and T2, and sets the logic level of selection signal S2 to L and H levels during periods T1 and T2. This causes selection circuit 440 to select trapezoidal waveform Adp1 during period T1 and trapezoidal waveform Bdp2 during period T2. As a result, drive signal selection circuit 420 outputs drive signal VOUT corresponding to the "medium dot MD" shown in FIG. 4.

[0075] Furthermore, when print data [SIH,SIL]=[0,1] is input to decoder 436, decoder 436 sets the logic level of selection signal S1 to H,L levels during periods T1 and T2, and sets the logic level of selection signal S2 to L,L levels during periods T1 and T2. As a result, selection circuit 440 selects trapezoidal waveform Adp1 during period T1, and selects neither trapezoidal waveform Adp2 nor trapezoidal waveform Bdp2 during period T2. As a result, drive signal selection circuit 420 outputs drive signal VOUT corresponding to the "small dot SD" shown in FIG. 4.

[0076] Furthermore, when print data [SIH,SIL]=[0,0] is input to the decoder 436, the decoder 436 sets the logic level of the selection signal S1 to L,L levels during periods T1 and T2, and sets the logic level of the selection signal S2 to H,L levels during periods T1 and T2. As a result, the selection circuit 440 selects the trapezoidal waveform Bdp1 during period T1, and selects neither the trapezoidal waveforms Adp2 nor Bdp2 during period T2. As a result, the drive signal selection circuit 420 outputs the drive signal VOUT corresponding to the "micro vibration BSD" shown in FIG. 4.

[0077] As described above, the drive signal selection circuit 420 selects or deselects the trapezoidal waveforms Adp1, Adp2 included in the drive signal COMA and the trapezoidal waveforms Bdp1, Bdp2 included in the drive signal COMB based on the input print data signal SI, latch signal LAT, change signal CH and clock signal SCK, thereby generating drive signals VOUT corresponding to each of the "large dot LD", "medium dot MD", "small dot SD" and "fine vibration BSD" corresponding to each of the p discharge sections 600 and outputting them to each of the p discharge sections 600.

[0078] 3. Structure of the liquid ejection device Next, the structure of the liquid ejection device 1 will be described. Fig. 9 is a diagram showing the structure of the liquid ejection device 1 when viewed from the side. As shown in Fig. 9, the liquid ejection device 1 includes a feed unit 3 that feeds out a medium P as a recording medium, a support unit 4 that supports the fed-out medium P, a transport unit 5 that transports the medium P supported by the support unit 4, a printing unit 6 that prints on the medium P transported by the transport unit 5, and a control unit 2 that controls the operation of each unit of the liquid ejection device 1, including the feed unit 3, the support unit 4, the transport unit 5, and the printing unit 6.

[0079] In the following description, the width direction of the liquid ejector 1, which is also the main scanning direction of the liquid ejector 1, is referred to as the X direction, the depth direction of the liquid ejector 1 is referred to as the Y direction, the height direction of the liquid ejector 1 is referred to as the Z direction, and the direction in which the medium P is transported is referred to as the transport direction F. In addition, the starting point side of the arrow indicating the illustrated X direction will be referred to as the -X side, and the tip side will be referred to as the +X side, the starting point side of the arrow indicating the illustrated Y direction will be referred to as the -Y side, and the tip side will be referred to as the +Y side, and the starting point side of the arrow indicating the illustrated Z direction will be referred to as the -Z side, and the tip side will be referred to as the +Z side. In the following description, the X direction, Y direction, and Z direction will be described as being orthogonal to one another, but this does not mean that the components of the liquid ejector 1 are limited to being arranged orthogonally.

[0080] The control unit 2 generates various signals for controlling the various components of the liquid ejection device 1 and outputs them to the corresponding components. The control unit 2 includes the control unit 10 described above. The control unit 2 is provided inside the outer shell of the liquid ejection device 1, for example, near a connector (not shown) to which a cable (not shown) through which an image signal PDATA input from an external device is connected, near a user interface (not shown) through which a user inputs operation information for the liquid ejection device 1, or near a connector (not shown) to which a cable (not shown) through which commercial alternating current voltage AC supplied from a commercial power source is connected. The control unit 2 is not limited to being formed on a single board, and may be formed to include multiple boards.

[0081] The unwinding unit 3 has a holding member 31. The holding member 31 rotatably holds a roll 32 on which the medium P is wound. The roll 32 rotates in one direction under the control of the control unit 2. As a result, the medium P wound on the roll 32 is unwound and unwound to the support unit 4.

[0082] The support unit 4 supports the medium P unwound from the roll body 32 and forms a transport path along which the medium P is transported. Specifically, the support unit 4 has a first support unit 41, a second support unit 42, and a third support unit 43. The first support unit 41 supports the medium P fed out from the feed unit 3 and guides it toward the second support unit 42. The second support unit 42 supports the medium P when the printing process is performed. The third support unit 43 supports the medium P after the printing process has been performed and guides it downstream in the transport direction F.

[0083] The transport unit 5 transports the medium P supported by the support unit 4 along the transport path. The transport unit 5 has a transport motor 51, a transport roller 52, and a driven roller 53. The transport motor 51 is driven to rotate under the control of the control unit 2. The transport roller 52 is located on the +Z side of the transport path for the medium P, and rotates in response to the rotational drive of the transport motor 51. The driven roller 53 is located on the -Z side of the transport path for the medium P, and together with the transport roller 52, holds the medium P being transported along the transport path. When the transport motor 51 is driven to rotate under the control of the control unit 2, the transport roller 52 rotates, and the medium P held between the transport roller 52 and the driven roller 53 is transported along the transport direction F.

[0084] The printing unit 6 is located on the -Z side of the transport path, and ejects ink onto the medium P under the control of the control unit 2. The configuration of the printing unit 6 will be described in detail below. FIG. 10 is a side view showing the structure of the printing unit 6 of the liquid ejection device 1. FIG. 11 is a front view showing the structure of the printing unit 6 of the liquid ejection device 1. FIG. 12 is a perspective view showing the structure of the printing unit 6 of the liquid ejection device 1. As shown in FIGS. 10, 11, and 12, the printing unit 6 has a carriage 71, a moving mechanism 61, a guide member 62, and a housing 81.

[0085] The carriage 71 has a carriage body 72 and a carriage cover 73. When the carriage 71 is viewed along the X direction, the carriage body 72 has a substantially L-shaped cross section. The carriage cover 73 is detachably attached to the carriage body 72. When the carriage cover 73 is attached to the carriage body 72, a closed space is formed in the carriage 71. The carriage 71 is arranged so that it can move back and forth along the X direction, with the +Z side of the substantially L-shaped carriage body 72 facing the medium P.

[0086] In the closed space of the carriage 71, which is constituted by the carriage body 72 and the carriage cover 73, liquid ejection heads 400-1 to 400-4 and ink sub-tanks 750-1 to 750-4 are provided.

[0087] The liquid ejection head 400 is mounted on the carriage 71 so that p nozzles 651 are aligned along the Y direction and the nozzles 651 are exposed from the +Z side of the carriage body 72. The liquid ejection heads 400-1 to 400-4 are aligned along the X direction from the -X side to the +X side in the order of liquid ejection heads 400-1, 400-2, 400-3, 400-4. The number of liquid ejection heads 400 in the liquid ejection device 1 is not limited to four.

[0088] The ink subtanks 750-1 to 750-4 temporarily store ink supplied to the printing unit 6 from ink containers (not shown) included in the liquid ejection device 1. These ink subtanks 750-1 to 750-4 are provided, for example, according to the colors of ink used in the liquid ejection device 1. The ink stored in the ink subtanks 750-1 to 750-4 is then supplied to the corresponding liquid ejection heads 400 and ejected from the p ejection units 600 included in the liquid ejection heads 400. Here, in the liquid ejection device 1 of this embodiment, the following description will be given assuming that the ink subtank 750-1 corresponds to the liquid ejection head 400-1, the ink subtank 750-2 corresponds to the liquid ejection head 400-2, the ink subtank 750-3 corresponds to the liquid ejection head 400-3, and the ink subtank 750-4 corresponds to the liquid ejection head 400-4. That is, the ink stored in the ink subtank 750-1 is supplied to the liquid ejection head 400-1 and ejected from the p ejection sections 600 that the liquid ejection head 400-1 has, the ink stored in the ink subtank 750-2 is supplied to the liquid ejection head 400-2 and ejected from the p ejection sections 600 that the liquid ejection head 400-2 has, the ink stored in the ink subtank 750-3 is supplied to the liquid ejection head 400-3 and ejected from the p ejection sections 600 that the liquid ejection head 400-3 has, and the ink stored in the ink subtank 750-4 is supplied to the liquid ejection head 400-4 and ejected from the p ejection sections 600 that the liquid ejection head 400-4 has.

[0089] Such ink subtanks 750-1 to 750-4 are preferably arranged near the corresponding liquid ejection heads 400. In the liquid ejection device 1 of this embodiment, the ink subtank 750-1 is arranged near the liquid ejection head 400-1 on the -X side of the liquid ejection head 400-1, the ink subtank 750-2 is arranged near the liquid ejection head 400-2 on the +X side of the liquid ejection head 400-1 and on the -X side of the liquid ejection head 400-2, the ink subtank 750-3 is arranged near the liquid ejection head 400-3 on the +X side of the liquid ejection head 400-2 and on the -X side of the liquid ejection head 400-3, and the ink subtank 750-4 is arranged near the liquid ejection head 400-4 on the +X side of the liquid ejection head 400-3 and on the -X side of the corresponding liquid ejection head 400-4.

[0090] Here, the ink subtanks 750-1 to 750-4 all have the same configuration, and when there is no need to distinguish between them, they may be simply referred to as ink subtanks 750. Furthermore, the number of ink subtanks 750 that the liquid ejection device 1 has is not limited to four, and may be three or less, or five or more, depending on the number of ink colors and the amount of ink used in the liquid ejection device 1. Furthermore, in the liquid ejection device 1 of this embodiment, the ink subtanks 750 and the liquid ejection heads 400 are described as having a one-to-one correspondence, but one ink subtank 750 may supply ink to multiple liquid ejection heads 400, or multiple ink subtanks 750 may supply ink to one liquid ejection head 400.

[0091] An ink heating unit 700 is attached to the +X side and the -X side of each ink subtank 750. That is, the liquid ejection device 1 of this embodiment has eight ink heating units 700 corresponding to the ink subtanks 750-1 to 750-4, respectively. As described above, the heating unit 710 of the ink heating unit 700 generates heat by the heating current Ihc based on the voltage signal VHC output by the power supply circuit 101. The temperature detection unit 720 of the ink heating unit 700 detects the temperature of the heating unit 710, and the temperature control circuit 500 controls the supply of the heating current Ihc to the heating unit 710 in accordance with the detection result. This controls the temperature of the heating unit 710 of the ink heating unit 700, and as a result, controls the temperature of the ink stored in the ink subtank 750 to which the ink heating unit 700 is attached.

[0092] In the following description, the ink heating unit 700 attached to the -X side of the ink subtank 750-1 corresponds to the ink heating unit 700-1 described above, the ink heating unit 700 attached to the +X side of the ink subtank 750-1 corresponds to the ink heating unit 700-2 described above, the ink heating unit 700 attached to the -X side of the ink subtank 750-2 corresponds to the ink heating unit 700-3 described above, and the ink heating unit 700 attached to the +X side of the ink subtank 750-2 corresponds to the ink heating unit 700-4 described above. In this description, the ink heating unit 700 attached to the -X side of ink subtank 750-3 corresponds to the ink heating unit 700-5 described above, the ink heating unit 700 attached to the +X side of ink subtank 750-3 corresponds to the ink heating unit 700-6 described above, the ink heating unit 700 attached to the -X side of ink subtank 750-4 corresponds to the ink heating unit 700-7 described above, and the ink heating unit 700 attached to the +X side of ink subtank 750-4 corresponds to the ink heating unit 700-8 described above. The number of ink heating units 700 attached to the ink subtank 750 is not limited to two, and may be one, or three or more. Furthermore, the ink heating units 700 may be attached to the +Y, -Y, -Z, or +Z side of the ink subtank 750.

[0093] The guide member 62 extends along the X direction and supports the carriage 71 so that it can move back and forth along the X direction. Specifically, the guide member 62 has a guide rail portion 63 extending along the X direction at the bottom of the side surface on the +Y side. Furthermore, the carriage main body 72 of the carriage 71 has a carriage support portion 64 at the bottom of the side surface on the -Y side. The carriage support portion 64 is slidably fitted into the guide rail portion 63, so that the carriage 71 is slidably supported by the guide member 62.

[0094] The movement mechanism 61 includes a motor (not shown). The movement mechanism 61 controls the forward and reverse rotation of the motor under the control of the control unit 2. The movement mechanism 61 converts the rotational force generated by the forward and reverse rotation of the motor into a movement force along the X direction of the carriage 71. This causes the carriage 71 to move back and forth along the X direction.

[0095] The housing 81 includes a substantially rectangular parallelepiped closed space. The closed space of the housing 81 houses the discharge control board 21, the heating control board 22, and the drive circuit boards 30-1 to 30-4. The +Y side end of the housing 81 is fixed to the -Y side end of the carriage main body 72. In other words, the discharge control board 21, the heating control board 22, and the drive circuit boards 30-1 to 30-4 are mounted on the carriage 71 via the housing 81. Note that the closed space of the housing 81 is not limited to a completely sealed space, but may be a space with an opening in part, or a space that is partially openable and closable.

[0096] The discharge control circuit 200 described above is mounted on the discharge control board 21, and a connector 28 is also provided. One or more cables 82 that electrically connect the control unit 2 and the discharge control board 21 are connected to the connector 28. As a result, a transmission signal Tx outputted from the main control circuit 100 included in the control unit 10 of the control unit 2 is inputted to the discharge control circuit 200 mounted on the discharge control board 21.

[0097] The drive circuit boards 30-1 to 30-4 are arranged side by side along the X direction in an upright position on the -Z side of the discharge control board 21. Specifically, the drive circuit boards 30-1 to 30-4 are arranged side by side along the X direction from the -X side to the +X side in the order of drive circuit boards 30-1, 30-2, 30-3, and 30-4. The drive circuit board 30-1 is mounted with the drive circuit 300-1 described above, the drive circuit board 30-2 is mounted with the drive circuit 300-2 described above, the drive circuit board 30-3 is mounted with the drive circuit 300-3 described above, and the drive circuit board 30-4 is mounted with the drive circuit 300-4 described above. Here, the drive circuit boards 30-1 to 30-4 all have the same configuration, and when there is no need to distinguish between them, they may be simply referred to as drive circuit boards 30. The following description will be given assuming that the drive circuit board 30 is provided with the drive circuit 300.

[0098] The discharge control board 21 and the drive circuit board 30 are connected via a connector 24. For example, a BtoB (Board to Board) connector that directly connects the discharge control board 21 and each of the drive circuit boards 30-1 to 30-4 can be used as such a connector 24. As a result, the basic drive signals dA and dB generated by the discharge control circuit 200 mounted on the discharge control board 21 are input to the drive circuit 300 mounted on the drive circuit board 30.

[0099] Connectors 84 and 85 are provided at the end of the drive circuit board 30 on the +Y side. Furthermore, a connection board 74 is located on the -Z side of the liquid ejection head 400, and connectors 76 and 77 are provided on the -Z side surface of the connection board 74, and a connector 75 is provided on the +Z side surface of the connection board 74. One end of a cable 86 is connected to the connector 84 of the drive circuit board 30, and the other end of the cable 86 is connected to the connector 76 provided on the connection board 74. One end of a cable 87 is connected to the connector 85 of the drive circuit board 30, and the other end of the cable 87 is connected to the connector 77 provided on the connection board 74. Furthermore, the connection board 74 is electrically connected to the liquid ejection head 400 via the connector 75. That is, the drive circuit board 30 and the liquid ejection head 400 are electrically connected via the cables 86 and 87, the connection board 74, and the connector 75. As a result, the drive signals COMA, COMB and the reference voltage signal VBS output by the drive circuit 300 provided on the drive circuit board 30 are supplied to the liquid ejection head 400.

[0100] Furthermore, in the liquid ejection device 1 of this embodiment, the clock signal SCK, latch signal LAT, change signal CH, and print data signal SI output by the ejection control circuit 200 mounted on the ejection control board 21 are also input to the drive circuit board 30 via the connector 24. The clock signal SCK, latch signal LAT, change signal CH, and print data signal SI input to the drive circuit board 30 are then propagated through a wiring pattern and cables 86 and 87 (not shown) provided on the drive circuit board 30, and input to the liquid ejection head 400. In other words, the drive circuit board 30 also functions as a relay board for propagating the clock signal SCK, latch signal LAT, change signal CH, and print data signal SI to the liquid ejection head 400.

[0101] In this case, the drive signals COMA, COMB and reference voltage signal VBS are high-voltage signals sufficient to drive the piezoelectric element 60, whereas the clock signal SCK, latch signal LAT, change signal CH and print data signal SI are low-voltage logic signals. In the liquid ejection device 1 of this embodiment, the high-voltage drive signals COMA, COMB and reference voltage signal VBS propagate through one of the cables 86, 87, and the low-voltage clock signal SCK, latch signal LAT, change signal CH and print data signal SI propagate through the other of the cables 86, 87. This reduces the risk of the high-voltage drive signals COMA, COMB and reference voltage signal VBS being superimposed on the low-voltage clock signal SCK, latch signal LAT, change signal CH and print data signal SI.

[0102] Here, in the liquid ejection device 1 of this embodiment, the description will be given assuming that the drive circuit board 30-1 is provided to correspond to the liquid ejection head 400-1, the drive circuit board 30-2 is provided to correspond to the liquid ejection head 400-2, the drive circuit board 30-3 is provided to correspond to the liquid ejection head 400-3, and the drive circuit board 30-4 is provided to correspond to the liquid ejection head 400-4. That is, the drive signals COMA1, COMB1 and reference voltage signal VBS1 output by the drive circuit 300-1 mounted on the drive circuit board 30-1, and the clock signal SCK, latch signal LAT1, change signal CH1 and print data signal SI1 propagating through the drive circuit board 30-1 are input to the liquid ejection head 400-1, and the drive signals COMA2, COMB2 and reference voltage signal VBS2 output by the drive circuit 300-2 mounted on the drive circuit board 30-2, and the clock signal SCK, latch signal LAT2, change signal CH2 and print data signal SI2 propagating through the drive circuit board 30-2 are input to the liquid ejection head 400-2. The drive signals COMA3, COMB3 and reference voltage signal VBS3 output by the drive circuit 300-3 mounted on the drive circuit board 30-3, and the clock signal SCK, latch signal LAT3, change signal CH3 and print data signal SI3 propagating through the drive circuit board 30-3 are input to the liquid ejection head 400-3, and the drive signals COMA4, COMB4 and reference voltage signal VBS4 output by the drive circuit 300-4 mounted on the drive circuit board 30-4, and the clock signal SCK, latch signal LAT4, change signal CH4 and print data signal SI4 propagating through the drive circuit board 30-4 are input to the liquid ejection head 400-4.

[0103] Here, the number of drive circuit boards 30 included in the liquid ejection device 1 is not limited to four, and may be three or less, or five or more. Furthermore, in the liquid ejection device 1 of this embodiment, the drive circuit boards 30 and the liquid ejection heads 400 are described as having a one-to-one correspondence, but a plurality of signals including drive signals COMA and COMB output from one drive circuit board 30 may be input to a plurality of liquid ejection heads 400, and a plurality of signals including drive signals COMA and COMB output from a plurality of drive circuit boards 30 may be input to a single liquid ejection head 400.

[0104] The heating control board 22 is located on the -Z side of the ejection control board 21 and on the -Y side of the drive circuit boards 30-1 to 30-4. The heating control board 22 is equipped with the temperature control circuit 500 and switches SW-1 to SW-8 described above, and is also provided with a connector 29. One or more cables 83 that electrically connect the control unit 2 and the heating control board 22 are connected to the connector 29. As a result, a voltage signal VHC output by the power supply circuit 101 included in the control unit 10 of the control unit 2 is input to the heating control board 22 via the cable 83. In addition, one end of eight cables 730 is connected to the heating control board 22. The other end of each of the eight cables 730 is connected to the ink heaters 700-1 to 700-8.

[0105] The heating control board 22 as described above branches the voltage signal VHC input from the power supply circuit 101 to correspond to the ink heating units 700-1 to 700-8. One of the branched voltage signals VHC is supplied to the ink heating unit 700-1 via switch SW-1 and cable 730, another of the branched voltage signals VHC is supplied to the ink heating unit 700-2 via switch SW-2 and cable 730, another of the branched voltage signals VHC is supplied to the ink heating unit 700-3 via switch SW-3 and cable 730, another of the branched voltage signals VHC is supplied to the ink heating unit 700-4 via switch SW-4 and cable 730, A different one of the branched voltage signals VHC is supplied to the ink heating unit 700-5 via switch SW-5 and cable 730, a different one of the branched voltage signals VHC is supplied to the ink heating unit 700-6 via switch SW-6 and cable 730, a different one of the branched voltage signals VHC is supplied to the ink heating unit 700-7 via switch SW-7 and cable 730, and a different one of the branched voltage signals VHC is supplied to the ink heating unit 700-8 via switch SW-8 and cable 730.

[0106] That is, the heating control board 22 has a wiring pattern through which the heating current Ihc-1 supplied to the heating unit 710 of the ink heating unit 700-1 propagates, a wiring pattern through which the heating current Ihc-2 supplied to the heating unit 710 of the ink heating unit 700-2 propagates, a wiring pattern through which the heating current Ihc-3 supplied to the heating unit 710 of the ink heating unit 700-3 propagates, and a wiring pattern through which the heating current Ihc-4 supplied to the heating unit 710 of the ink heating unit 700-4 propagates. The wiring pattern includes a wiring pattern through which a heating current Ihc-5 supplied to the heating section 710 of the ink heating section 700-5 propagates, a wiring pattern through which a heating current Ihc-6 supplied to the heating section 710 of the ink heating section 700-6 propagates, a wiring pattern through which a heating current Ihc-7 supplied to the heating section 710 of the ink heating section 700-7 propagates, and a wiring pattern through which a heating current Ihc-8 supplied to the heating section 710 of the ink heating section 700-8 propagates.

[0107] Then, the heating currents Ihc-1 to Ihc-8 propagated through the heating control board 22 are propagated through the cables 730 corresponding to the ink heating units 700-1 to 700-8, respectively, and are supplied to the heating units 710 included in the ink heating units 700-1 to 700-8, respectively. In the following description, the cable 730 through which the heating current Ihc-1 supplied to the heating unit 710 of the ink heating unit 700-1 propagates will be referred to as cable 730-1, the cable 730 through which the heating current Ihc-2 supplied to the heating unit 710 of the ink heating unit 700-2 will be referred to as cable 730-2, the cable 730 through which the heating current Ihc-3 supplied to the heating unit 710 of the ink heating unit 700-3 will be referred to as cable 730-3, and the cable 730 through which the heating current Ihc-4 supplied to the heating unit 710 of the ink heating unit 700-4 will be referred to as cable 730-4. The cable 730 through which the heating current Ihc-5 supplied to the heating section 710 of the ink heating section 700-5 is transmitted may be referred to as cable 730-5, the cable 730 through which the heating current Ihc-6 supplied to the heating section 710 of the ink heating section 700-6 is transmitted may be referred to as cable 730-6, the cable 730 through which the heating current Ihc-7 supplied to the heating section 710 of the ink heating section 700-7 is transmitted may be referred to as cable 730-7, and the cable 730 through which the heating current Ihc-8 supplied to the heating section 710 of the ink heating section 700-8 is transmitted may be referred to as cable 730-8.

[0108] Furthermore, temperature detection signals Tmp-1 to Tmp-8 indicating the temperatures of the ink heating units 700-1 to 700-8, respectively, are input to the heating control board 22 via a cable 730. The temperature detection signals Tmp-1 to Tmp-8 input to the heating control board 22 are propagated through a wiring pattern provided on the heating control board 22 and input to the temperature control circuit 500. The temperature control circuit 500 generates switch control signals Sc-1 to Sc-8 corresponding to the input temperature detection signals Tmp-1 to Tmp-8, respectively, and outputs them to the corresponding switches SW-1 to SW-8. This controls the amount of heating currents Ihc-1 to Ihc-8 supplied to the ink heating units 700-1 to 700-8, respectively, and controls the temperature of the heating unit 710 of each of the ink heating units 700-1 to 700-8. As a result, the temperature of the ink stored in the ink subtank 750-1 to which the ink heating units 700-1 and 700-2 are attached, the temperature of the ink stored in the ink subtank 750-2 to which the ink heating units 700-3 and 700-4 are attached, the temperature of the ink stored in the ink subtank 750-3 to which the ink heating units 700-5 and 700-6 are attached, and the temperature of the ink stored in the ink subtank 750-4 to which the ink heating units 700-7 and 700-8 are attached are controlled.

[0109] The ink used in the liquid ejection device 1 has a certain viscosity in order to reduce the risk of bleeding when it lands on the medium P. In particular, in the case of a textile printer that uses a cloth or the like as the medium P, there is a high possibility of bleeding when it lands on the medium P, and therefore high-viscosity ink is used. However, when the viscosity of the ink becomes high, it becomes difficult to precisely control the ejection of the ink, which may result in a deterioration in the quality of the image formed on the medium P.

[0110] To address this problem, in the liquid ejection device 1 of this embodiment, the ink supplied to the liquid ejection device 1 is temporarily stored in an ink subtank 750 provided near the liquid ejection head 400, and the ink heating unit 700 controls the temperature of the ink stored in the ink subtank 750, thereby controlling the viscosity of the ink supplied to the liquid ejection head 400. This reduces the risk of a decrease in the ejection accuracy of the ink ejected from the liquid ejection head 400, and also reduces the risk of a decrease in the quality of the image formed on the medium P.

[0111] Furthermore, the liquid ejection device 1 may have a circulation path for circulating ink between the ink subtank 750, in which the temperature of the ink is controlled, and the liquid ejection head 400, which ejects the ink. Even when the temperature of the ink stored in the ink subtank 750 is controlled by the ink heating unit 700, there is a risk that the temperature of the ink will drop in the supply path that supplies the ink from the ink subtank 750 to the liquid ejection head 400. To address this drop in ink temperature, the liquid ejection device 1 has a circulation path for circulating ink between the ink subtank 750 and the liquid ejection head 400. By controlling the temperature of the ink stored in the ink subtank 750, it is possible to control the temperature of the ink circulating in the circulation path. This further reduces the risk of a decrease in the ejection accuracy of the ink ejected from the liquid ejection head 400, and also further reduces the risk of a decrease in the quality of the image formed on the medium P.

[0112] As described above, the liquid ejection device 1 of this embodiment is a liquid ejection device 1 that forms an image on a medium P by ejecting ink, and includes liquid ejection heads 400-1 to 400-4 that eject ink, an ink subtank 750-1 that supplies ink to liquid ejection head 400-1, an ink subtank 750-2 that supplies ink to liquid ejection head 400-2, an ink subtank 750-3 that supplies ink to liquid ejection head 400-3, an ink subtank 750-4 that supplies ink to liquid ejection head 400-4, ink heating units 700-1 and 700-2 that are attached to the ink subtank 750-1 and at least a portion of which comes into contact with the ink subtank 750-1, and an ink heater 700-1 that is attached to the ink subtank 750-2. ink heating units 700-3 and 700-4, at least a portion of which contacts the ink subtank 750-2 by being attached to the ink subtank 750-3; ink heating units 700-5 and 700-6, at least a portion of which contacts the ink subtank 750-3 by being attached to the ink subtank 750-3; ink heating units 700-7 and 700-8, at least a portion of which contacts the ink subtank 750-4 by being attached to the ink subtank 750-4; a heating control board 22 including a wiring pattern through which heating currents Ihc-1 to Ihc-8 supplied to the heating units 710 of each of the ink heating units 700-1 to 700-8 propagate; and a carriage 71 on which the heating control board 22 is mounted, which moves back and forth along the X direction intersecting the transport direction F in which the medium P is transported. Equipped with.

[0113] In the liquid ejection device 1 configured as described above, the temperature of the ink stored in the ink subtank 750 is controlled by controlling the temperature of the heating unit 710 of the ink heating unit 700 attached to the ink subtank 750. In this case, since the ink subtank 750 is located near the liquid ejection head 400, the temperature of the ink ejected from the liquid ejection head 400 can be controlled. This makes it possible to control the viscosity of the ink ejected from the liquid ejection head 400, thereby reducing the risk of a decrease in the ejection accuracy of the ink ejected from the liquid ejection head 400. Furthermore, if the liquid ejection device 1 has a circulation path for circulating ink between the ink subtank 750 and the liquid ejection head 400, it is also possible to control the temperature of the ink circulating between the ink subtank 750 and the liquid ejection head 400, further reducing the risk of a decrease in the ejection accuracy of the ink ejected from the liquid ejection head 400.

[0114] Here, the configuration of the heating control board 22 through which the heating current Ihc supplied to the heating unit 710 of the ink heating unit 700 to control the temperature of the ink stored in the ink subtank 750 propagates will be described. In describing the configuration of the heating control board 22, FIGS. 13 to 17 illustrate the mutually orthogonal x, y, and z directions. In the following description, the starting point side of an arrow indicating the x direction will be referred to as the -x side, and the leading end side thereof as the +x side. The starting point side of an arrow indicating the y direction will be referred to as the -y side, and the leading end side thereof as the +y side. The starting point side of an arrow indicating the z direction will be referred to as the -z side, and the leading end side thereof as the +z side. In the liquid ejection device 1 of this embodiment, the x direction, y direction, and z direction shown in FIGS. 13 to 17 will be described as corresponding to the X direction, Y direction, and Z direction shown in FIGS. 9 to 12, respectively. That is, the heating control board 22 is provided in the housing 81 so that the x direction shown in Figures 13 to 17 is aligned with the X direction shown in Figures 9 to 12, the y direction shown in Figures 13 to 17 is aligned with the Y direction shown in Figures 9 to 12, and the z direction shown in Figures 13 to 17 is aligned with the Z direction shown in Figures 9 to 12. Note that the arrangement of the heating control board 22 in the storage space of the housing 81 is not limited to this.

[0115] Fig. 13 is a diagram showing an example of the cross-sectional structure of heating control board 22. As shown in Fig. 13, heating control board 22 includes surface 211 and surface 212 different from surface 211. Surfaces 211 and 212 are positioned opposite each other in the z direction, with surface 211 on the -z side and surface 212 on the +z side.

[0116] The heating control substrate 22 includes layers 231, 232, and 233, a plurality of layers 240, and layers 251 and 252.

[0117] Layers 231, 232, and 233 are located between surfaces 211 and 212, and are arranged in the order of layer 231, layer 232, and layer 233 in the z direction from the −z side to the +z side. Each of layers 231, 232, and 233 is provided with a wiring pattern for transmitting signals input to heating control board 22 and a wiring pattern for electrically connecting various electronic components provided on heating control board 22. Each of layers 231, 232, and 233 is made of a material with excellent electrical conductivity for transmitting various signals, and includes a wiring pattern formed of, for example, copper foil. That is, layers 231, 232, and 233 correspond to wiring layers on heating control board 22 on which wiring patterns for transmitting various signals are provided. In other words, heating control board 22 is located between surfaces 211 and 212 and has multiple wiring layers, including layers 231, 232, and 233 on which wiring patterns for transmitting signals are provided.

[0118] The multiple layers 240 are located between the layer 231 and the layer 232 and between the layer 232 and the layer 233 in the z direction. The multiple layers 240 correspond to insulating layers that mutually insulate the layers 231, 232, and 233, on which the wiring patterns are provided. The multiple layers 240 are made of a material with excellent insulating properties, such as epoxy glass formed by impregnating glass fiber cloth with epoxy resin. In other words, the heating control board 22 has multiple insulating layers located between the surface 211 and the surface 212, for mutually insulating the layers 231, 232, and 233, on which the wiring patterns are provided.

[0119] Layer 251 is located on the -z side of layer 231, and layer 252 is located on the +z side of layer 233. That is, layer 251 is located so as to cover the surface on the -z side of the heating control board 22, and layer 252 is located so as to cover the surface on the +z side of the heating control board 22. These layers 251 and 252 also function as protective layers that protect the wiring patterns formed on layers 231 and 233 from the outside of the heating control board 22. Such layers 251 and 252 are configured to include, for example, solder resist. That is, the heating control board 22 has layer 251 located so as to cover the surface on the -z side of the heating control board 22 and constituting at least a part of surface 211 of the heating control board 22, and layer 252 located so as to cover the surface on the +z side of the heating control board 22 and constituting at least a part of surface 212 of the heating control board 22.

[0120] As described above, the heating control board 22 of this embodiment is a so-called multilayer board that includes a surface 211 and a surface 212 different from the surface 211 and has multiple wiring layers between the surfaces 211 and 212. The number of wiring layers included in the heating control board 22 is not limited to the example shown in FIG. 13 . That is, in addition to the layers 231, 232, and 233, the heating control board 22 may include a wiring layer provided with a wiring pattern through which a power supply voltage is propagated, a wiring layer provided with a wiring pattern through which a ground potential is supplied, a wiring layer provided with a wiring pattern through which other signals are propagated, and so on. Hereinafter, the heating control board 22 viewed from the −z side along the z direction may be referred to as a plan view of the heating control board 22.

[0121] Next, specific examples of wiring patterns provided on layers 231 to 233 corresponding to wiring layers will be described. Fig. 14 is a diagram showing an example of a wiring pattern provided on layer 231. Fig. 15 is a diagram showing an example of a wiring pattern provided on layer 232. Fig. 16 is a diagram showing an example of a wiring pattern provided on layer 233. As shown in Figs. 14 to 16, the heating control board 22 is a substantially rectangular multilayer board including two sides facing each other in the x direction and two sides facing each other in the y direction, and includes wires pih1 to pih5, wires pt1 to pt8, wires ps1 to ps8, wires pc1 to pc8, and a plurality of wires TM provided on layer 231, wires psc1 to pcs8 and wires ptm1 to ptm8 provided on layer 232, and wires pih6 to pih10 provided on layer 233. 14 to 16, the connector 29, the temperature control circuit 500, and the switches SW-1 to SW-8 mounted on the heating control board 22, as well as one end of the cables 730-1 to 730-8 attached to the heating control board 22, are shown by dashed lines.

[0122] The multiple wirings TM are electrically connected to terminals (not shown) of the temperature control circuit 500. This allows various signals propagating through the heating control board 22 to be input to the temperature control circuit 500, and various signals output by the temperature control circuit 500 to propagate through the heating control board 22 toward corresponding components.

[0123] The wiring pih1 is a wiring pattern that extends along the x direction, and the end on the +x side is connected to the connector 29 via a via or the like.

[0124] The wires pih2 to pih5 are each a wiring pattern extending along the y direction, and each has its -y-side end connected to the wire pih1. Specifically, the -y-side end of the wire pih2 is connected to the wire pih1 and extends along the y direction toward the +y side. The wire pih3 is located on the +x side of the wire pih2, has its -y-side end connected to the wire pih1, and extends along the y direction toward the +y side. The wire pih4 is located on the +x side of the wire pih3, has its -y-side end connected to the wire pih1, and extends along the y direction toward the +y side. The wire pih5 is located on the +x side of the wire pih4, has its -y-side end connected to the wire pih1, and extends along the y direction toward the +y side. That is, the wires pih2 to pih5 are arranged side by side so as to branch off from the wire pih1.

[0125] The line pc1 is located on the -x side of the +y side end of the line pih2, and is electrically connected to the line pih2 via the switch SW-1. The line pc2 is located on the +x side of the +y side end of the line pih2, and is electrically connected to the line pih2 via the switch SW-2. That is, one end of the switch SW-1 and one end of the switch SW-2 are connected to the +y side end of the line pih2, the other end of the switch SW-1 is connected to the line pc1, and the other end of the switch SW-2 is connected to the line pc2. One end of the cable 730-1 is connected to the line pc1, and one end of the cable 730-2 is connected to the line pc2.

[0126] Wire pc3 is located on the -x side of the +y end of wire pih3 and is electrically connected to wire pih3 via switch SW-3. Wire pc4 is located on the +x side of the +y end of wire pih3 and is electrically connected to wire pih3 via switch SW-4. That is, one end of switch SW-3 and one end of switch SW-4 are connected to the +y end of wire pih3, the other end of switch SW-3 is connected to wire pc3, and the other end of switch SW-4 is connected to wire pc4. One end of cable 730-3 is connected to wire pc3, and one end of cable 730-4 is connected to wire pc4.

[0127] Wire pc5 is located on the -x side of the +y end of wire pih4 and is electrically connected to wire pih4 via switch SW-5. Wire pc6 is located on the +x side of the +y end of wire pih4 and is electrically connected to wire pih4 via switch SW-6. That is, one end of switch SW-5 and one end of switch SW-6 are connected to the +y end of wire pih4, the other end of switch SW-5 is connected to wire pc5, and the other end of switch SW-6 is connected to wire pc6. One end of cable 730-5 is connected to wire pc5, and one end of cable 730-6 is connected to wire pc6.

[0128] The line pc7 is located on the -x side of the +y end of the line pih5 and is electrically connected to the line pih5 via the switch SW-7. The line pc8 is located on the +x side of the +y end of the line pih5 and is electrically connected to the line pih5 via the switch SW-8. That is, one end of the switch SW-7 and one end of the switch SW-8 are connected to the +y end of the line pih5, the other end of the switch SW-7 is connected to the line pc7, and the other end of the switch SW-8 is connected to the line pc8. One end of the cable 730-7 is connected to the line pc7, and one end of the cable 730-8 is connected to the line pc8.

[0129] Here, one end of each of the cables 730-1 to 730-8 may be connected to the heating control board 22 via a connector (not shown), or may be connected directly to the heating control board 22 by soldering or the like.

[0130] The switch SW-1 is also connected to a line ps1. The line ps1 is connected to one end of a line psc1 provided on the layer 232 via a via or the like (not shown). The other end of the line psc1 is connected to at least one of the multiple lines TM provided on the layer 231 via a via or the like (not shown). In other words, the switch SW-1 and the temperature control circuit 500 are electrically connected to each other via the line pcs1.

[0131] The switch SW-2 is also connected to a line ps2. The line ps2 is connected to one end of a line psc2 provided on the layer 232 via a via or the like (not shown). The other end of the line psc2 is connected to at least one of the multiple lines TM provided on the layer 231 via a via or the like (not shown). In other words, the switch SW-2 and the temperature control circuit 500 are electrically connected to each other via the line pcs2.

[0132] The switch SW-3 is also connected to a line ps3. The line ps3 is connected to one end of a line psc3 provided on the layer 232 via a via or the like (not shown). The other end of the line psc3 is connected to at least one of the multiple lines TM provided on the layer 231 via a via or the like (not shown). In other words, the switch SW-3 and the temperature control circuit 500 are electrically connected via the line pcs3.

[0133] The switch SW-4 is also connected to a line ps4. The line ps4 is connected to one end of a line psc4 provided on the layer 232 via a via or the like (not shown). The other end of the line psc4 is connected to at least one of the multiple lines TM provided on the layer 231 via a via or the like (not shown). In other words, the switch SW-4 and the temperature control circuit 500 are electrically connected via the line pcs4.

[0134] The switch SW-5 is also connected to a line ps5. The line ps5 is connected to one end of a line psc5 provided on the layer 232 via a via or the like (not shown). The other end of the line psc5 is connected to at least one of the multiple lines TM provided on the layer 231 via a via or the like (not shown). In other words, the switch SW-5 and the temperature control circuit 500 are electrically connected via the line pcs5.

[0135] The switch SW-6 is also connected to a line ps6. The line ps6 is connected to one end of a line psc6 provided on the layer 232 via a via or the like (not shown). The other end of the line psc6 is connected to at least one of the multiple lines TM provided on the layer 231 via a via or the like (not shown). In other words, the switch SW-6 and the temperature control circuit 500 are electrically connected via the line pcs6.

[0136] The switch SW-7 is also connected to a line ps7. The line ps7 is connected to one end of a line psc7 provided on the layer 232 via a via or the like (not shown). The other end of the line psc7 is connected to at least one of the multiple lines TM provided on the layer 231 via a via or the like (not shown). In other words, the switch SW-7 and the temperature control circuit 500 are electrically connected via the line pcs7.

[0137] The switch SW-8 is also connected to a line ps8. The line ps8 is connected to one end of a line psc8 provided on the layer 232 via a via or the like (not shown). The other end of the line psc8 is connected to at least one of the multiple lines TM provided on the layer 231 via a via or the like (not shown). In other words, the switch SW-8 and the temperature control circuit 500 are electrically connected via the line pcs8.

[0138] One end of the cable 730-1 is also connected to a wiring pt1. The wiring pt1 is connected to one end of a wiring ptm1 provided on the layer 232 via a via or the like (not shown). The other end of the wiring ptm1 is connected to at least one of the multiple wirings TM provided on the layer 231 via a via or the like (not shown). In other words, the cable 730-1 and the temperature control circuit 500 are electrically connected via the wiring ptm1.

[0139] One end of the cable 730-2 is also connected to the wiring pt2. The wiring pt2 is connected to one end of the wiring ptm2 provided on the layer 232 via a via or the like (not shown). The other end of the wiring ptm2 is connected to at least one of the multiple wirings TM provided on the layer 231 via a via or the like (not shown). In other words, the cable 730-2 and the temperature control circuit 500 are electrically connected via the wiring ptm2.

[0140] One end of the cable 730-3 is also connected to the wiring pt3. The wiring pt3 is connected to one end of the wiring ptm3 provided on the layer 232 via a via or the like (not shown). The other end of the wiring ptm3 is connected to at least one of the multiple wirings TM provided on the layer 231 via a via or the like (not shown). In other words, the cable 730-3 and the temperature control circuit 500 are electrically connected via the wiring ptm3.

[0141] One end of the cable 730-4 is also connected to a wiring pt4. The wiring pt4 is connected to one end of a wiring ptm4 provided on the layer 232 via a via or the like (not shown). The other end of the wiring ptm4 is connected to at least one of the multiple wirings TM provided on the layer 231 via a via or the like (not shown). In other words, the cable 730-4 and the temperature control circuit 500 are electrically connected via the wiring ptm4.

[0142] One end of the cable 730-5 is also connected to a wiring pt5. The wiring pt5 is connected to one end of a wiring ptm5 provided on the layer 232 via a via or the like (not shown). The other end of the wiring ptm5 is connected to at least one of the multiple wirings TM provided on the layer 231 via a via or the like (not shown). In other words, the cable 730-5 and the temperature control circuit 500 are electrically connected via the wiring ptm5.

[0143] One end of the cable 730-6 is also connected to a wiring pt6. The wiring pt6 is connected to one end of a wiring ptm6 provided on the layer 232 via a via or the like (not shown). The other end of the wiring ptm6 is connected to at least one of the multiple wirings TM provided on the layer 231 via a via or the like (not shown). In other words, the cable 730-6 and the temperature control circuit 500 are electrically connected via the wiring ptm6.

[0144] One end of the cable 730-7 is also connected to a wiring pt7. The wiring pt7 is connected to one end of a wiring ptm7 provided on the layer 232 via a via or the like (not shown). The other end of the wiring ptm7 is connected to at least one of the multiple wirings TM provided on the layer 231 via a via or the like (not shown). In other words, the cable 730-7 and the temperature control circuit 500 are electrically connected via the wiring ptm7.

[0145] One end of the cable 730-8 is also connected to a wiring pt8. The wiring pt8 is connected to one end of a wiring ptm8 provided on the layer 232 via a via or the like (not shown). The other end of the wiring ptm8 is connected to at least one of the multiple wirings TM provided on the layer 231 via a via or the like (not shown). In other words, the cable 730-8 and the temperature control circuit 500 are electrically connected via the wiring ptm8.

[0146] The wiring pih6 is a wiring pattern extending along the x direction, and its end on the +x side is connected via a via or the like to the wiring pih1 provided on the layer 231. In this case, the wiring pih6 is positioned so that at least a portion thereof overlaps with the wiring pih1 in a plan view of the heating control substrate 22.

[0147] The wires pih7 to pih10 are wiring patterns that extend along the y direction, and the ends of each on the -y side are connected to the wire pih6.

[0148] Specifically, the −y-side end of the wiring pih7 is connected to the wiring pih6 and extends toward the +y-side along the y-direction. The +y-side end of the wiring pih7 is connected to the wiring pih2 provided on the layer 231 via a via or the like. At this time, the wiring pih7 is positioned so as to at least partially overlap with the wiring pih2 in a planar view of the heating control substrate 22. The wiring pih8 is positioned on the +x-side of the wiring pih7, has its −y-side end connected to the wiring pih6, and extends toward the +y-side along the y-direction. The +y-side end of the wiring pih8 is connected to the wiring pih3 provided on the layer 231 via a via or the like. At this time, the wiring pih8 is positioned so as to at least partially overlap with the wiring pih3 in a planar view of the heating control substrate 22. The wiring pih9 is positioned on the +x-side of the wiring pih8, has its −y-side end connected to the wiring pih6, and extends toward the +y-side along the y-direction. The +y-side end of the wiring pih9 is connected to the wiring pih4 provided on the layer 231 via a via or the like. At this time, the wiring pih9 is positioned so that at least a portion thereof overlaps with the wiring pih4 in a planar view of the heating control substrate 22. The wiring pih10 is positioned on the +x side of the wiring pih9, connects to the wiring pih6 at its -y-side end, and extends toward the +y side in the y direction. The +y-side end of the wiring pih10 is connected to the wiring pih5 provided on the layer 231 via a via or the like. At this time, the wiring pih10 is positioned so that at least a portion thereof overlaps with the wiring pih5 in a planar view of the heating control substrate 22.

[0149] That is, the wirings pih1 to pih5 provided on the layer 231 and the wirings pih6 to pih10 provided on the layer 233 are electrically arranged in parallel and positioned so as to at least partially overlap when the heating control board 22 is seen in a plan view.

[0150] Here, various signals transmitted through the heating control board 22 and details of the temperature control of the heating section 710 of each of the ink heating sections 700-1 to 700-8 will be described.

[0151] The connector 29 to which the voltage signal VHC output from the power supply circuit 101 is input and the cable 730-1 connected to the ink heating unit 700-1 attached to the ink subtank 750-1 are electrically connected via the wires pih1 and pih6 provided on the layer 231, the wires pih2 and pih7 provided on the layer 233, the switch SW-1, and the wire pc1. That is, the heating current Ihc-1 of the heating current Ihc based on the voltage signal VHC output from the power supply circuit 101 propagates through the wires pih1 and pih6 and the wires pih2 and pih7, and is supplied to the heating unit 710 of the ink heating unit 700-1 via the switch SW-1, the wire pc1, and the cable 730-1.

[0152] Furthermore, the temperature detection unit 720 included in the ink heating unit 700-1 detects the temperature of the heating unit 710 included in the ink heating unit 700-1, and generates and outputs a temperature detection signal Tmp-1 based on the detected temperature. The temperature detection signal Tmp-1 output by the temperature detection unit 720 is input to the heating control board 22 via a cable 730-1. The temperature detection signal Tmp-1 then propagates through wiring pt1 and wiring ptm1 provided on the heating control board 22, and is input to the temperature control circuit 500 via wiring TM.

[0153] The temperature control circuit 500 generates and outputs a switch control signal Sc-1 in response to the input temperature detection signal Tmp-1. The switch control signal Sc-1 is input to the heating control board 22 via wiring TM. The switch control signal Sc-1 propagates through wiring psc1 and wiring ps1 provided on the heating control board 22 and is input to the control terminal of the switch SW-1. This controls the conductive state of the switch SW-1 and the amount of heating current Ihc-1 supplied to the ink heating unit 700-1. In other words, the temperature of the heating unit 710 of the ink heating unit 700-1, which generates heat in response to the amount of heating current Ihc-1, is controlled.

[0154] Similarly, the connector 29, to which the voltage signal VHC output by the power supply circuit 101 is input, and the cable 730-2, which is connected to the ink heater 700-2 attached to the ink subtank 750-1, are electrically connected via wires pih1 and pih6, wires pih2 and pih7, switch SW-2, and wire pc2. Therefore, the heating current Ihc-2 propagates through the wires pih1 and pih6, and wires pih2 and pih7, and is supplied to the heater 710 of the ink heater 700-2 via switch SW-2, wire pc2, and cable 730-2. In addition, the temperature detector 720 of the ink heater 700-2 outputs a temperature detection signal Tmp-2 based on the temperature of the heater 710. The temperature detection signal Tmp-2 is input to the heating control board 22 via cable 730-2, then propagates through wires pt2 and ptm2, and is input to the temperature control circuit 500 via wire TM. The temperature control circuit 500 outputs a switch control signal Sc-2 in response to the input temperature detection signal Tmp-2. After being input to the heating control board 22, the switch control signal Sc-2 propagates through wires psc2 and ps2 and is input to the control terminal of switch SW-2. This controls the conductive state of switch SW-2 and the amount of heating current Ihc-2 supplied to the ink heating unit 700-2. As a result, the temperature of the heating unit 710 of the ink heating unit 700-2, which generates heat in accordance with the amount of heating current Ihc-2, is controlled.

[0155] Similarly, the connector 29, to which the voltage signal VHC output by the power supply circuit 101 is input, and the cable 730-3, which is connected to the ink heater 700-3 attached to the ink subtank 750-2, are electrically connected via wires pih1 and pih6, wires pih3 and pih8, switch SW-3, and wire pc3. Therefore, the heating current Ihc-3 propagates through the wires pih1 and pih6, and wires pih3 and pih8, and is supplied to the heater 710 of the ink heater 700-3 via switch SW-3, wire pc3, and cable 730-3. In addition, the temperature detector 720 of the ink heater 700-3 outputs a temperature detection signal Tmp-3 based on the temperature of the heater 710. The temperature detection signal Tmp-3 is input to the heating control board 22 via cable 730-3, then propagates through wires pt3 and ptm3, and is input to the temperature control circuit 500 via wire TM. The temperature control circuit 500 outputs a switch control signal Sc-3 in response to the input temperature detection signal Tmp-3. After being input to the heating control board 22, the switch control signal Sc-3 propagates through wires psc3 and ps3 and is input to the control terminal of switch SW-3. This controls the conductive state of switch SW-3, and thereby controls the amount of heating current Ihc-3 supplied to the ink heating unit 700-3. As a result, the temperature of the heating unit 710 of the ink heating unit 700-3, which generates heat in accordance with the amount of heating current Ihc-3, is controlled.

[0156] Similarly, the connector 29, to which the voltage signal VHC output by the power supply circuit 101 is input, and the cable 730-4, which is connected to the ink heater 700-4 attached to the ink subtank 750-2, are electrically connected via wires pih1 and pih6, wires pih3 and pih8, switch SW-4, and wire pc4. Therefore, the heating current Ihc-4 propagates through the wires pih1 and pih6, and wires pih3 and pih8, and is supplied to the heater 710 of the ink heater 700-4 via switch SW-4, wire pc4, and cable 730-4. In addition, the temperature detector 720 of the ink heater 700-4 outputs a temperature detection signal Tmp-4 based on the temperature of the heater 710. The temperature detection signal Tmp-4 is input to the heating control board 22 via cable 730-4, then propagates through wires pt4 and ptm4, and is input to the temperature control circuit 500 via wire TM. The temperature control circuit 500 outputs a switch control signal Sc-4 in response to the input temperature detection signal Tmp-4. After being input to the heating control board 22, the switch control signal Sc-4 propagates through wires psc4 and ps4 and is input to the control terminal of switch SW-4. This controls the conductive state of switch SW-4, and thereby controls the amount of heating current Ihc-4 supplied to the ink heating unit 700-4. As a result, the temperature of the heating unit 710 of the ink heating unit 700-4, which generates heat in accordance with the amount of heating current Ihc-4, is controlled.

[0157] Similarly, the connector 29, to which the voltage signal VHC output by the power supply circuit 101 is input, and the cable 730-5, which is connected to the ink heater 700-5 attached to the ink subtank 750-3, are electrically connected via wires pih1 and pih6, wires pih4 and pih9, switch SW-5, and wire pc5. Therefore, the heating current Ihc-5 propagates through the wires pih1 and pih6, and wires pih4 and pih9, and is supplied to the heater 710 of the ink heater 700-5 via switch SW-5, wire pc5, and cable 730-5. In addition, the temperature detector 720 of the ink heater 700-5 outputs a temperature detection signal Tmp-5 based on the temperature of the heater 710. The temperature detection signal Tmp-5 is input to the heating control board 22 via cable 730-5, then propagates through wires pt5 and ptm5, and is input to the temperature control circuit 500 via wire TM. The temperature control circuit 500 outputs a switch control signal Sc-5 in response to the input temperature detection signal Tmp-5. After being input to the heating control board 22, the switch control signal Sc-5 propagates through wires psc5 and ps5 and is input to the control terminal of the switch SW-5. This controls the conductive state of the switch SW-5 and the amount of heating current Ihc-5 supplied to the ink heating unit 700-5. As a result, the temperature of the heating unit 710 of the ink heating unit 700-5, which generates heat in accordance with the amount of heating current Ihc-5, is controlled.

[0158] Similarly, the connector 29, to which the voltage signal VHC output by the power supply circuit 101 is input, and the cable 730-6, which is connected to the ink heater 700-6 attached to the ink subtank 750-3, are electrically connected via wires pih1 and pih6, wires pih4 and pih9, switch SW-6, and wire pc6. Therefore, the heating current Ihc-6 propagates through the wires pih1 and pih6, and wires pih4 and pih9, and is supplied to the heater 710 of the ink heater 700-6 via switch SW-6, wire pc6, and cable 730-6. In addition, the temperature detector 720 of the ink heater 700-6 outputs a temperature detection signal Tmp-6 based on the temperature of the heater 710. The temperature detection signal Tmp-6 is input to the heating control board 22 via cable 730-6, then propagates through wires pt6 and ptm6, and is input to the temperature control circuit 500 via wire TM. The temperature control circuit 500 outputs a switch control signal Sc-6 in response to the input temperature detection signal Tmp-6. After being input to the heating control board 22, the switch control signal Sc-6 propagates through wires psc6 and ps6 and is input to the control terminal of the switch SW-6. This controls the conductive state of the switch SW-6, and controls the amount of heating current Ihc-6 supplied to the ink heating unit 700-6. As a result, the temperature of the heating unit 710 of the ink heating unit 700-6, which generates heat in accordance with the amount of heating current Ihc-6, is controlled.

[0159] Similarly, the connector 29, to which the voltage signal VHC output by the power supply circuit 101 is input, and the cable 730-7, which is connected to the ink heater 700-7 attached to the ink subtank 750-4, are electrically connected via wires pih1 and pih6, wires pih5 and pih10, switch SW-7, and wire pc7. Therefore, the heating current Ihc-7 propagates through the wires pih1 and pih6, and wires pih5 and pih10, and is supplied to the heater 710 of the ink heater 700-7 via the switch SW-7, wire pc7, and cable 730-7. In addition, the temperature detector 720 of the ink heater 700-7 outputs a temperature detection signal Tmp-7 based on the temperature of the heater 710. The temperature detection signal Tmp-7 is input to the heating control board 22 via cable 730-7, then propagates through wires pt7 and ptm7, and is input to the temperature control circuit 500 via wire TM. The temperature control circuit 500 outputs a switch control signal Sc-7 in response to the input temperature detection signal Tmp-7. After being input to the heating control board 22, the switch control signal Sc-7 propagates through wires psc7 and ps7 and is input to the control terminal of the switch SW-7. This controls the conductive state of the switch SW-7 and the amount of heating current Ihc-7 supplied to the ink heating unit 700-7. As a result, the temperature of the heating unit 710 of the ink heating unit 700-7, which generates heat in accordance with the amount of heating current Ihc-7, is controlled.

[0160] Similarly, the connector 29, to which the voltage signal VHC output by the power supply circuit 101 is input, and the cable 730-8, which is connected to the ink heater 700-8 attached to the ink subtank 750-4, are electrically connected via wires pih1 and pih6, wires pih5 and pih10, switch SW-8, and wire pc8. Therefore, the heating current Ihc-8 propagates through the wires pih1 and pih6, and wires pih5 and pih10, and is supplied to the heater 710 of the ink heater 700-8 via switch SW-8, wire pc8, and cable 730-8. In addition, the temperature detector 720 of the ink heater 700-8 outputs a temperature detection signal Tmp-8 based on the temperature of the heater 710. The temperature detection signal Tmp-8 is input to the heating control board 22 via cable 730-8, then propagates through wires pt8 and ptm8, and is input to the temperature control circuit 500 via wire TM. The temperature control circuit 500 outputs a switch control signal Sc-8 in response to the input temperature detection signal Tmp-8. After being input to the heating control board 22, the switch control signal Sc-8 propagates through wires psc8 and ps8 and is input to the control terminal of the switch SW-8. This controls the conductive state of the switch SW-8, and controls the amount of heating current Ihc-8 supplied to the ink heating unit 700-8. As a result, the temperature of the heating unit 710 of the ink heating unit 700-8, which generates heat in accordance with the amount of heating current Ihc-8, is controlled.

[0161] As described above, the heating unit 710 of each of the ink heating units 700-1 to 700-8 generates heat in accordance with the amount of heating current Ihc-1 to Ihc-8 supplied to it. Therefore, a current of several amperes may be supplied to the heating unit 710 of each of the ink heating units 700-1 to 700-8 depending on the temperature. Therefore, a large current of several amperes may flow through the wirings pih2 to pih5 and wirings pih7 to pih10 of the heating control board 22, through which the heating currents Ihc-1 to Ihc-8 flow. Furthermore, a current of several amperes to several tens of amperes may flow through the wirings pih1 and pih6, through which the heating current Ihc, which is the sum of the heating currents Ihc-1 to Ihc8, flows.

[0162] The heating control board 22, through which such a large current flows, generates heat due to the current values ​​of the heating currents Ihc, Ihc-1 to Ihc-8 and the impedance of the wiring pih1 to pih10 through which the heating currents Ihc, Ihc-1 to Ihc-8 flow. In particular, in the liquid ejection device 1 of this embodiment, the heating currents Ihc, Ihc-1 to Ihc-8 are large, ranging from several amperes to several tens of amperes, so the heating control board 22 reaches a high temperature. Therefore, the temperature of the heating control board 22 may remain high for a certain period of time even after the supply of the heating currents Ihc-1 to Ihc-8 is stopped. In other words, the heating control board 22 may maintain a high temperature even when the power supply to the liquid ejection device 1 is stopped.

[0163] For this reason, when there is a risk that an operator may come into contact with heating control board 22, such as during an inspection process carried out when manufacturing liquid discharger 1 or during maintenance of liquid discharger 1, measures are taken such as suspending work and waiting for a certain period of time to allow the heat generated by heating control board 22 to be sufficiently released. However, when this measure is taken, because the certain period of waiting is not dependent on the actual temperature of heating control board 22, there is a risk that the operator will wait even if the temperature of heating control board 22 has dropped sufficiently, which could result in a decrease in work efficiency and could also lead to the operator starting work even if the temperature of heating control board 22 has not dropped sufficiently.

[0164] That is, in the liquid ejection device 1 having the heating unit 710 as shown in this embodiment, the temperature of the ink ejected from the liquid ejection head 400 can be controlled by the heating unit 710, which improves the ink ejection accuracy, but this creates a new problem in that the operator cannot grasp the heat generation state of the heating control board 22 during the inspection process or maintenance of the liquid ejection device 1, which reduces workability and may reduce the convenience of the liquid ejection device 1. To address this problem, the liquid ejection device 1 of this embodiment has a notification function that notifies the operator whether the temperature of the heating control board 22 is high or not.

[0165] An example of a specific configuration of the heating control board 22 having such a reporting function will be described below. FIG. 17 is a diagram showing an example of the configuration of the surface 211 of the heating control board 22. As shown in FIG. 17, the surface 211 of the heating control board 22 is provided with temperature reporting units 260-1 to 260-5 that report the temperature of the heating control board 22, in addition to the temperature control circuit 500, switches SW-1 to SW-8, connector 29, and cables 730-1 to 730-8 described above. That is, the liquid discharger 1 includes temperature reporting units 260-1 to 260-5 provided on the surface 211 of the heating control board 22. Here, the temperature reporting units 260-1 to 260-5 all have the same configuration, and when there is no need to distinguish between them, they may be simply referred to as the temperature reporting unit 260. Note that in FIG. 17, the wiring pattern provided on the layer 231 located adjacent to the surface 211 is shown by dashed lines.

[0166] The temperature notification unit 260 can use, for example, a reversible thermochromic paint. The reversible thermochromic paint includes a leuco dye, which is an electron-donating compound; a color developer, which is an electron-accepting compound; and a decolorizer for controlling the color change temperature range. When the temperature of the thermochromic paint changes from an initial state below a predetermined threshold temperature to a thermochromic state above the predetermined threshold temperature, the color of the thermochromic paint changes from its initial state color. When the temperature of the thermochromic paint changes from a state above the predetermined threshold temperature to an initial state below the predetermined threshold temperature, the color of the thermochromic paint returns to its initial state color. Examples of the initial color of the thermochromic paint include light pink, light green, and white, while the color of the thermochromic paint in the thermochromic state includes purple, blue-purple, and black. The initial and thermochromic colors of the thermochromic paint are not limited to these, and various colors can be used depending on the characteristics of the leuco dye.

[0167] That is, temperature reporting unit 260 includes an initial state indicating that the temperature of temperature reporting unit 260 is below a predetermined threshold temperature and a temperature indicating state indicating that the temperature of temperature reporting unit 260 is equal to or higher than the predetermined threshold temperature, and the initial state and the temperature indicating state are different colors. Furthermore, the initial state and the temperature indicating state of temperature reporting unit 260 change reversibly depending on whether the temperature of temperature reporting unit 260 is below the predetermined threshold temperature or equal to or higher than the predetermined threshold temperature. In other words, temperature reporting unit 260 indicates that the temperature of temperature reporting unit 260 is below the threshold temperature in the initial state and indicates that the temperature of temperature reporting unit 260 is equal to or higher than the threshold temperature in the temperature indicating state, and the initial state and the temperature indicating state change reversibly.

[0168] This makes it possible to visually notify the worker of the temperature state of the heating control board 22. As a result, the worker can easily grasp the heat generation state of the heating control board 22, reducing the risk of a significant decrease in workability and a decrease in the convenience of the liquid discharger 1.

[0169] Furthermore, by using a temperature indicating paint as the temperature indicating unit 260, whether the temperature indicating unit 260 is in the initial state or the temperature indicating state changes depending on the temperature of the temperature indicating unit 260. In other words, the initial state and the temperature indicating state change reversibly regardless of whether power is supplied to the liquid ejection device 1 including the power supply circuit 101. As a result, even when power is not being supplied to the liquid ejection device 1, the operator can easily grasp the heat generation state of the heating control board 22, reducing the risk of a significant decrease in workability and a decrease in the convenience of the liquid ejection device 1.

[0170] Furthermore, the area of ​​heating control board 22 where temperature reporting unit 260 is provided is preferably an area that is silk-screened in white. This allows the operator to more clearly grasp the color change of the thermochromic paint used as temperature reporting unit 260, and as a result, temperature reporting unit 260 can more clearly notify the operator of the heat generation state of heating control board 22.

[0171] Furthermore, it is sufficient for temperature reporting unit 260 to be able to reversibly change between the initial state and the temperature indicating state in accordance with the temperature of temperature reporting unit 260. Therefore, instead of or in addition to the temperature indicating paint, temperature reporting unit 260 may include a thermoelectric conversion element and a light-emitting element that emits light in accordance with the output of the thermoelectric conversion element.

[0172] In this case, the thermoelectric conversion element included in the temperature reporting unit 260 outputs power according to the temperature detected by the thermoelectric conversion element, and the light-emitting element included in the temperature reporting unit 260 emits light with power according to the temperature detected by the thermoelectric conversion element. That is, the output power output by the thermoelectric conversion element when the temperature of the thermoelectric conversion element is below a predetermined threshold temperature differs from the output power output by the thermoelectric conversion element when the temperature of the thermoelectric conversion element is equal to or higher than the predetermined threshold temperature. Therefore, the light-emitting state of the light-emitting element that emits light according to the output of the thermoelectric conversion element also differs between when the temperature of the thermoelectric conversion element is below the predetermined threshold temperature and when the temperature of the thermoelectric conversion element is equal to or higher than the predetermined threshold temperature.

[0173] That is, even if the temperature reporting unit 260 is configured to include a thermoelectric conversion element and a light-emitting element that emits light in response to the output of the thermoelectric conversion element, the temperature reporting unit 260 can visually report the temperature state of the heating control board 22 to the operator based on the difference in the light-emitting state of the light-emitting element between the initial state and the temperature-indicating state. As a result, the operator can easily grasp the heat generation state of the heating control board 22, reducing the risk of a significant decrease in workability and a decrease in the convenience of the liquid discharger 1.

[0174] Furthermore, the above-mentioned predetermined threshold temperature at which the state of the temperature indicating paint used as the temperature reporting units 260-1 to 260-5 changes between the initial state and the temperature indicating state is preferably set in the range of 40 to 70 degrees C. In other words, it is preferable that the temperature indicating paint used as the temperature reporting units 260-1 to 260-5 is a temperature indicating paint whose initial state and temperature indicating state change in the range of 40 to 70 degrees C.

[0175] In the case of the liquid ejection device 1 that ejects ink by driving the piezoelectric element 60 as shown in this embodiment, if the temperature of the liquid ejection head 400 becomes high, the stability of the operation of the liquid ejection head 400 may decrease. Therefore, if the temperature of the ink supplied to the liquid ejection head 400 becomes high, there is a greater risk of the stability of the operation of the liquid ejection head 400 decreasing. By using a temperature indicating paint that changes between its initial state and its temperature indicating state in a range of 40 to 70 degrees as the temperature indicating paint used in the temperature indicating units 260-1 to 260-5, it becomes possible to visually recognize the temperature state of the ink supplied to the liquid ejection head 400. In other words, the temperature indicating units 260-1 to 260-5 can indicate the state of the ink supplied to the liquid ejection head 400.

[0176] Here, the temperature indicating paints used for each of the temperature indicating units 260-1 to 260-5 may have different properties, and the color of each of the temperature indicating units 260-1 to 260-5 in their initial state may be different, and similarly, the color of each of the temperature indicating units 260-1 to 260-5 in their temperature indicating state may be different.

[0177] Next, an example of the arrangement of the temperature notification unit 260 on the heating control board 22 will be described.

[0178] The temperature notification unit 260-1 is positioned so that at least a portion thereof overlaps with the wiring pih1 when viewed from the -z side along the z direction, which is the normal direction of the heating control board 22, in a plan view of the heating control board 22. In this case, the temperature notification unit 260-1 is positioned on the +x side of the connection point of the wiring pih1 extending in the x direction, to which one end of the wiring pih5 is connected. In other words, the temperature notification unit 260-1 is positioned closer to the connector 29 than any of the wirings pih2 to pih5 of the wiring pih1 extending in the x direction. This allows the temperature notification unit 260-1 to detect the temperature of the wiring pih1.

[0179] The temperature notification unit 260-2 is positioned so that at least a portion overlaps with the wiring pih2 when viewed from the -z side along the z direction, which is the normal direction of the heating control board 22, in a plan view of the heating control board 22. As a result, the temperature notification unit 260-2 detects the temperature of the wiring pih2. The temperature notification unit 260-3 is positioned so that at least a portion overlaps with the wiring pih3 when viewed from the -z side along the z direction, which is the normal direction of the heating control board 22, in a plan view of the heating control board 22. As a result, the temperature notification unit 260-3 detects the temperature of the wiring pih3. The temperature notification unit 260-4 is positioned so that at least a portion overlaps with the wiring pih4 when viewed from the -z side along the z direction, which is the normal direction of the heating control board 22, in a plan view of the heating control board 22. As a result, the temperature notification unit 260-4 detects the temperature of the wiring pih4. Furthermore, the temperature notification unit 260-5 is positioned so that at least a portion thereof overlaps with the wiring pih5 when viewed from the -z side along the z direction, which is the normal direction of the heating control board 22, in a plan view of the heating control board 22. This allows the temperature notification unit 260-5 to detect the temperature of the wiring pih5.

[0180] That is, at least a portion of the temperature notification unit 260-1 is positioned in the normal direction of the heating control board 22 so as to overlap at least a portion of the wiring pih1 provided on the layer 231 located closest to the surface 211 among the plurality of wiring layers that the heating control board 22 has, at least a portion of the temperature notification unit 260-2 is positioned in the normal direction of the heating control board 22 so as to overlap at least a portion of the wiring pih2 provided on the layer 231 located closest to the surface 211 among the plurality of wiring layers that the heating control board 22 has, and at least a portion of the temperature notification unit 260-3 is positioned in the normal direction of the heating control board 22 so as to overlap at least a portion of the wiring pih3 provided on the layer 231 located closest to the surface 211 among the plurality of wiring layers that the heating control board 22 has. At least a portion of the temperature notification unit 260-4 is positioned so as to overlap with at least a portion of the wiring pih3 provided on the layer 231 of the wiring layers that is located closest to the surface 211, in the normal direction of the heating control board 22, and at least a portion of the temperature notification unit 260-5 is positioned so as to overlap with at least a portion of the wiring pih5 provided on the layer 231 of the wiring layers that is located closest to the surface 211, in the normal direction of the heating control board 22.

[0181] In other words, no different wiring patterns are positioned between the temperature reporting units 260-1 to 260-5 and the wirings pih1 to pih5 whose temperatures are measured by the temperature reporting units 260-1 to 260-5. This improves the accuracy of detecting the temperatures of the wirings pih1 to pih5, which can become particularly hot, on the heating control board 22.

[0182] 17, on the heating control board 22, the temperature reporting units 260-2 to 260-5 are preferably positioned in a row in the x direction that intersects with the z direction that is the normal direction of the heating control board 22. This improves the visibility of the temperature reporting units 260-2 to 260-5 when determining the temperature of the heating control board 22.

[0183] Here, the liquid ejection head 400-1 is an example of a first ejection head, the ink sub-tank 750-1 that supplies ink to the liquid ejection head 400-1 is an example of a first liquid supply unit, at least one of the heating unit 710 included in the ink heating unit 700-1 that contacts at least a portion of the ink sub-tank 750-1 or the heating unit 710 included in the ink heating unit 700-2 is an example of a first heating element, at least one of the heating current Ihc-1 that heats the heating unit 710 included in the ink heating unit 700-1 and the heating current Ihc-2 that heats the heating unit 710 included in the ink heating unit 700-2 is an example of a first drive current, the wiring pih2 through which the heating currents Ihc-1 and Ihc-2 propagate is an example of a first propagation wiring, and the temperature indicator 260-2 that is arranged to overlap with the wiring pih2 is an example of a first temperature indicator. The initial state of temperature notification unit 260-2 is an example of the first state, the temperature indicating state of temperature notification unit 260-2 is an example of the second state, and the threshold temperature at which the initial state and the temperature indicating state of temperature notification unit 260-2 change is an example of the first threshold.

[0184] Furthermore, the liquid ejection head 400-2 is an example of a second ejection head, the ink sub-tank 750-2 that supplies ink to the liquid ejection head 400-2 is an example of a second liquid supply unit, at least one of the heating unit 710 included in the ink heating unit 700-3 that contacts at least a portion of the ink sub-tank 750-2 and the heating unit 710 included in the ink heating unit 700-4 is an example of a second heating element, at least one of the heating current Ihc-3 that heats the heating unit 710 included in the ink heating unit 700-3 and the heating current Ihc-4 that heats the heating unit 710 included in the ink heating unit 700-4 is an example of a second drive current, the wiring pih3 through which the heating currents Ihc-3 and Ihc-4 propagate is an example of a second propagation wiring, and the temperature notification unit 260-3 that is arranged to overlap with the wiring pih3 is an example of a second temperature indicator. The initial state of temperature notification unit 260-3 is an example of the third state, the temperature indicating state of temperature notification unit 260-3 is an example of the fourth state, and the threshold temperature at which the initial state and the temperature indicating state of temperature notification unit 260-3 change is an example of the second threshold.

[0185] Furthermore, temperature notification units 260-2 to 260-5 provided on heating control board 22 are an example of a plurality of temperature indicators, heating control board 22 is an example of a wiring board, power supply circuit 101 that outputs heating currents Ihc, Ihc-1 to Ihc-8 that propagate through heating control board 22 is an example of a drive current output circuit, surface 211 of heating control board 22 is an example of a first surface, surface 212 is an example of a second surface, and of the plurality of wiring layers that heating control board 22 has, layer 231 located closest to surface 211 is an example of a propagation wiring layer.

[0186] 4. Effects As described above, the liquid ejection device 1 of this embodiment comprises a liquid ejection head 400-1 that ejects ink, an ink subtank 750-1 that supplies ink to the liquid ejection head 400-1, a heating unit 710 included in the ink heating unit 700-1, at least a portion of which is in contact with the ink subtank 750-1, and a heating unit 710 included in the ink heating unit 700-2, a heating control board 22 including a surface 211, a surface 212 different from the surface 211, and wiring pih2 through which at least one of the heating current Ihc-1 supplied to the heating unit 710 included in the ink heating unit 700-1 and the heating current Ihc-2 supplied to the heating unit 710 included in the ink heating unit 700-2 propagates, and a temperature notification unit 260-2 provided on the surface 211.

[0187] In the liquid ejection device 1 of this embodiment, the temperature notification unit 260-2 indicates that the temperature of the temperature notification unit 260-2 is below the threshold temperature in the initial state, and indicates that the temperature of the temperature notification unit 260-2 is equal to or higher than the threshold temperature in the temperature indicating state, with the initial state and the temperature indicating state changing reversibly. This allows the temperature notification unit 260-2 to indicate whether the detected temperature is a low temperature below the threshold temperature or a high temperature above the threshold temperature. Furthermore, the temperature notification unit 260-2 is positioned so that at least a portion of it overlaps with at least a portion of the wiring pih2 in the normal direction of the heating control board 22. This allows the temperature notification unit 260-2 to efficiently detect the temperature of the wiring pih2 on the heating control board 22, which may become high.

[0188] That is, in the liquid ejector 1 of this embodiment, the temperature notification unit 260-2 can efficiently detect heat generation in the heating control board 22 that occurs due to the presence of a propagation path through which a large current flows, and can notify the operator of the detection result. This allows the operator to easily understand the heat generation state of the heating control board 22. As a result, even in a liquid ejector 1 through which a large current flows due to the presence of a heating unit 710 that heats ink, there is a reduced risk of reduced workability during inspection processes during manufacturing and maintenance of the liquid ejector 1, and there is also a reduced risk of reduced convenience of the liquid ejector 1.

[0189] Furthermore, the liquid ejection device 1 of this embodiment includes a liquid ejection head 400-2 that ejects ink, an ink sub-tank 750-2 that supplies ink to the liquid ejection head 400-2, a heating unit 710 included in the ink heating unit 700-3, at least a portion of which is in contact with the ink sub-tank 750-2, and a heating unit 710 included in the ink heating unit 700-4, and a temperature notification unit 260-3 provided on the surface 211, and the heating control board 22 includes wiring pih3 through which at least one of a heating current Ihc-3 supplied to the heating unit 710 included in the ink heating unit 700-3 and a heating current Ihc-4 supplied to the heating unit 710 included in the ink heating unit 700-4 propagates.

[0190] In the liquid ejector 1 of this embodiment, the temperature indicator 260-3 indicates that the temperature of the temperature indicator 260-3 is below the threshold temperature in its initial state and indicates that the temperature of the temperature indicator 260-3 is equal to or higher than the threshold temperature in its temperature-indicating state. The initial state and the temperature-indicating state change reversibly, and the temperature indicator 260-3 is positioned so that at least a portion of the temperature indicator 260-3 overlaps with at least a portion of the wiring pih2 in the normal direction of the heating control board 22. This allows the liquid ejector 1 to efficiently detect heat generation in the heating control board 22 and notify the operator of the detection results, even when the liquid ejector 1 has multiple propagation paths through which a large current flows. This allows the operator to easily grasp the heat generation state of the heating control board 22. As a result, even in a liquid ejector 1 in which a large current flows because it has a heating unit 710 that heats ink, the risk of reduced workability during inspection processes during manufacturing and maintenance of the liquid ejector 1 is further reduced, and the risk of reduced convenience of the liquid ejector 1 is also further reduced.

[0191] As described above, the liquid ejector 1 of this embodiment allows the operator to easily grasp the heat generation state of the heating control board 22. Therefore, even if the liquid ejector 1 is a textile printer that uses highly viscous ink and therefore has a heating unit 710 that heats the ink, and therefore a large current flows, the risk of a decrease in workability during inspection processes in the manufacturing stage and maintenance of the liquid ejector 1 is further reduced, and the risk of a decrease in the convenience of the liquid ejector 1 is also further reduced.

[0192] 5. Variations In the liquid ejection device 1 of this embodiment described above, each of the temperature notification units 260-1 to 260-5 provided on the heating control board 22 has been described as changing between an initial state and a temperature indicating state depending on the temperature of the temperature notification unit 260. However, each of the temperature notification units 260-1 to 260-5 includes an initial state indicating that the temperature of the temperature notification unit 260 is below a predetermined threshold temperature, a first temperature indicating state among the temperature indicating states indicating that the temperature of the temperature notification unit 260 is equal to or higher than the predetermined threshold temperature, and a second temperature indicating state among the temperature indicating states indicating that the temperature of the temperature notification unit 260 is equal to or higher than a high threshold temperature that is higher than the predetermined threshold temperature, and the initial state, the first temperature indicating state and the second temperature indicating state may be different colors.

[0193] This makes it possible to visually notify the worker of the details of the temperature state of the heating control board 22. As a result, the worker can easily grasp the heat generation state of the heating control board 22 in more detail, further reducing the risk of a significant decrease in workability and reducing the risk of a decrease in the convenience of the liquid discharger 1.

[0194] Here, the second temperature indicating state of temperature reporting unit 260-1 is an example of a fifth state, and the high temperature threshold temperature at which temperature reporting unit 260-1 changes between the first and second temperature indicating states is an example of a third threshold.

[0195] Although the embodiments and modifications have been described above, the present invention is not limited to these embodiments and can be embodied in various forms without departing from the spirit of the present invention. For example, the above embodiments can be combined as appropriate.

[0196] The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects). The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects as the configurations described in the embodiments or that can achieve the same purpose. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments.

[0197] The following can be derived from the above-described embodiment and modifications.

[0198] One aspect of the liquid ejection device is A liquid ejection device that forms an image on a medium by ejecting a liquid, a first ejection head that ejects liquid; a first liquid supply unit that supplies liquid to the first ejection head; a first heating element at least a portion of which is in contact with the first liquid supply unit; a wiring substrate including a first surface, a second surface different from the first surface, and a first propagation wiring through which a first drive current supplied to the first heating element propagates; a first temperature indicating portion provided on the first surface; Equipped with the first temperature indicator indicates that the temperature of the first temperature indicator is less than a first threshold value in a first state, and indicates that the temperature of the first temperature indicator is equal to or greater than the first threshold value in a second state, and the first state and the second state change reversibly; At least a portion of the first temperature indicator overlaps with at least a portion of the first propagation wire in the normal direction of the wiring substrate.

[0199] This liquid ejection device has a first temperature indicator that indicates that the temperature is below a first threshold in a first state and that the temperature is equal to or higher than the first threshold in a second state, and the first state and the second state change reversibly.At least a portion of the first temperature indicator is positioned so as to overlap with at least a portion of the first propagation wiring in the normal direction of the wiring substrate, so that the first temperature indicator can efficiently detect whether the wiring substrate is hot and notify the operator.

[0200] In one aspect of the liquid ejection device, The first temperature indicating portion may have a different color in the first state and in the second state.

[0201] According to this liquid ejection device, the color of the first temperature indicating portion is different between the first state and the second state, so that whether the wiring board is at a high temperature or not can be visually notified to the operator.

[0202] In one aspect of the liquid ejection device, a carriage that moves back and forth along a main scanning direction that intersects with a transport direction in which the medium is transported; The wiring board may be mounted on the carriage.

[0203] In one aspect of the liquid ejection device, a drive current output circuit that outputs the first drive current; The first state and the second state may be changed reversibly regardless of whether or not power supply to the drive current output circuit is supplied.

[0204] According to this liquid ejection device, the first temperature indicator can efficiently detect whether the wiring board is at a high temperature due to residual heat after the power supply to the liquid ejection device is stopped.

[0205] In one aspect of the liquid ejection device, the wiring substrate has a plurality of wiring layers located between the first surface and the second surface, the plurality of wiring layers includes a propagation wiring layer in which at least a portion of the first propagation wiring is provided, The propagation wiring layer may be located closest to the first surface among the plurality of wiring layers.

[0206] According to this liquid ejection device, the efficiency of the first temperature indicator in detecting whether the wiring substrate is at a high temperature is improved.

[0207] In one aspect of the liquid ejection device, At least a portion of the first temperature indicator may overlap, in the normal direction, at least a portion of the first propagation wire provided in the propagation wiring layer.

[0208] According to this liquid ejection device, the efficiency of the first temperature indicator in detecting whether the wiring substrate is at a high temperature is improved.

[0209] In one aspect of the liquid ejection device, a second ejection head that ejects liquid; a second liquid supply unit that supplies liquid to the second ejection head; a second heating element at least a portion of which is in contact with the second liquid supply unit; a second temperature indicating section provided on the first surface; Equipped with the wiring substrate includes a second propagation wiring through which a second drive current supplied to the second heating element propagates; the second temperature indicator indicates that the temperature of the second temperature indicator is less than a second threshold value in a third state, and indicates that the temperature of the second temperature indicator is equal to or greater than the second threshold value in a fourth state, and the third state and the fourth state change reversibly; At least a portion of the second temperature indicator may overlap at least a portion of the second propagation wire in the normal direction.

[0210] According to this liquid ejection device, The third state indicates that the temperature is below a second threshold, and the fourth state indicates that the temperature is above the second threshold, and the second temperature indicator changes reversibly between the third state and the fourth state. At least a portion of the second temperature indicator is positioned so as to overlap with at least a portion of the second propagation wiring in the normal direction of the wiring substrate, thereby making it possible to efficiently detect whether the wiring substrate is hot over a wide range.

[0211] In one aspect of the liquid ejection device, the wiring substrate has a plurality of temperature indicating portions including the first temperature indicating portion and the second temperature indicating portion, The plurality of temperature indicating portions may be positioned in a row in a direction intersecting the normal direction.

[0212] According to this liquid ejection device, it is possible to efficiently notify the operator of the detection result as to whether or not the wiring board is at a high temperature.

[0213] In one aspect of the liquid ejection device, the first temperature indicator indicates that the temperature of the first propagation wire is equal to or higher than the first threshold value and equal to or higher than a third threshold value in a fifth state; The first temperature indicating portion may have different colors in the first state, the second state, and the fifth state.

[0214] According to this liquid ejection device, the color of the first temperature indicator differs between the first state, the second state, and the third state, so that the temperature of the wiring board can be divided into multiple stages and visually notified to the operator whether the temperature is high or not.

[0215] In one aspect of the liquid ejection device, It may also be a textile printer.

[0216] In one aspect of the liquid ejection device, The first threshold may be in the range of 40 degrees to 70 degrees.

[0217] In one aspect of the liquid ejection device, The first temperature indicating portion may include a temperature indicating paint.

[0218] In one aspect of the liquid ejection device, The first temperature indicator may include a thermoelectric conversion element and a light emitting element. [Explanation of symbols]

[0219] 1...liquid ejection device, 2...control section, 3...feeding section, 4...support section, 5...conveying section, 6...printing section, 10...control unit, 20...head unit, 21...ejection control board, 22...heating control board, 24, 28, 29...connectors, 30...drive circuit board, 31...holding member, 32...roll body, 41...first support section, 42...second support section, 43...third support section, 51...conveying motor, 52...conveying roller, 53...driven roller, 60...piezoelectric element, 61...moving mechanism , 62...guide member, 63...guide rail portion, 64...carriage support portion, 71...carriage, 72...carriage main body, 73...carriage cover, 74...connection board, 75-77...connector, 81...casing, 82, 83...cable, 84, 85...connector, 86, 87...cable, 100...main control circuit, 101...power supply circuit, 200...discharge control circuit, 211, 212...surface, 231-233, 240, 251, 252...layer, 260...temperature temperature notification unit, 300...drive circuit, 310...drive signal output circuit, 320...reference voltage signal output circuit, 400...liquid ejection head, 420...drive signal selection circuit, 430...selection control circuit, 432...shift register, 434...latch circuit, 436...decoder, 440...selection circuit, 442a, 442b...inverters, 444a, 444b...transfer gates, 500...temperature control circuit, 600...ejection unit, 601...piezoelectric body, 611, 612... Electrode, 621...diaphragm, 631...cavity, 632...nozzle plate, 641...reservoir, 651...nozzle, 661...supply port, 700...ink heating unit, 710...heating unit, 720...temperature detection unit, 730...cable, 750...ink subtank, P...medium, SW...switch, TM, pc1 to pc8, pcs1 to pcs8, pih1 to pih10, ps1 to ps8, psc1 to psc8, pt1 to pt8, ptm1 to ptm8...wiring

Claims

1. A liquid ejection device that forms an image on a medium by ejecting a liquid, a first ejection head that ejects liquid; a first liquid supply unit that supplies liquid to the first ejection head; a first heating element at least a portion of which is in contact with the first liquid supply portion; a wiring substrate including a first surface, a second surface different from the first surface, and a first propagation wiring through which a first drive current supplied to the first heating element propagates; a first temperature indicating portion provided on the first surface; Equipped with the first temperature indicator indicates that the temperature of the first temperature indicator is less than a first threshold value in a first state, and indicates that the temperature of the first temperature indicator is equal to or greater than the first threshold value in a second state, and the first state and the second state change reversibly; At least a portion of the first temperature indicator overlaps with at least a portion of the first propagation wiring in a normal direction of the wiring substrate. A liquid ejection device characterized by:

2. The first temperature indicating portion has a different color in the first state and in the second state. The liquid ejection device according to claim 1 .

3. a carriage that moves back and forth along a main scanning direction that intersects with a transport direction in which the medium is transported; The wiring board is mounted on the carriage.

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

4. a drive current output circuit that outputs the first drive current; the first state and the second state are reversibly changed regardless of whether or not power supply to the drive current output circuit is supplied.

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

5. the wiring substrate has a plurality of wiring layers located between the first surface and the second surface, the plurality of wiring layers includes a propagation wiring layer on which at least a portion of the first propagation wiring is provided, the propagation wiring layer is located closest to the first surface among the plurality of wiring layers; 5. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

6. At least a portion of the first temperature indicator overlaps with at least a portion of the first propagation wiring provided in the propagation wiring layer in the normal direction.

6. The liquid ejection device according to claim 5.

7. a second ejection head that ejects liquid; a second liquid supply unit that supplies liquid to the second ejection head; a second heating element at least a portion of which is in contact with the second liquid supply portion; a second temperature indicating portion provided on the first surface; Equipped with the wiring substrate includes a second propagation wiring through which a second drive current supplied to the second heating element propagates; the second temperature indicator indicates that the temperature of the second temperature indicator is less than a second threshold value in a third state, and indicates that the temperature of the second temperature indicator is equal to or greater than the second threshold value in a fourth state, and the third state and the fourth state change reversibly; At least a portion of the second temperature indicator overlaps with at least a portion of the second propagation wiring in the normal direction.

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

8. the wiring substrate has a plurality of temperature indicating portions including the first temperature indicating portion and the second temperature indicating portion, The plurality of temperature indicating portions are positioned in a row in a direction intersecting the normal direction.

8. The liquid ejection device according to claim 7.

9. the first temperature indicator indicates that the temperature of the first propagation wire is equal to or higher than the first threshold value and equal to or higher than a third threshold value in a fifth state; the first temperature indicating portion has a different color in the first state, the second state, and the fifth state; 9. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

10. It is a textile printer, 10. The liquid ejection device according to claim 1, wherein the ejection head is a nozzle.

11. the first threshold is in the range of 40 degrees to 70 degrees; 11. The liquid ejection device according to claim 1.

12. The first temperature indicating portion includes a temperature indicating paint.

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

13. The first temperature indicator includes a thermoelectric conversion element and a light emitting element.

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

Images