Liquid ejection device

Abstract

The present invention provides a liquid ejection device that can improve the problem of heat generated in a transmission path with a large current flowing. The liquid ejection device forms an image on a medium by ejecting liquid, and comprises: 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 that includes a first surface, a second surface different from the first surface, and a first transmission wiring that transmits a first driving current supplied to the first heating element; a first temperature indicating unit that is disposed on the first surface, the first temperature indicating unit in a first state indicates that the temperature of the first temperature indicating unit is less than a first threshold value, and in a second state indicates that the temperature of the first temperature indicating unit is above the first threshold value, the first state and the second state are reversibly changeable, and at least a portion of the first temperature indicating unit overlaps with at least a portion of the first transmission wiring in the normal direction of the wiring substrate.

Description

Technical Field

[0001] The invention relates to a liquid ejecting device. Background Art

[0002] There is a known technology that can achieve stable ejection characteristics by adjusting the temperature of the ink in a liquid ejection device that ejects a liquid such as ink onto a medium, thereby controlling the viscosity of the ejected ink. For example, Patent Document 1 discloses a technology that can achieve stable ejection of the ink by individually adjusting the temperature of the ink for each type of ink in a liquid ejection device that can eject a plurality of types of ink.

[0003] However, in the liquid ejection device 1 having a heating element (heat exchange mechanism) for adjusting the temperature of ink as described in Patent Document 1, in the liquid ejection device that supplies a large current to the heating element, the heat generated in the propagation path through which the large current flows will also increase. With respect to the heat generated in the propagation path through which the large current flows, the technology described in Patent Document 1 is not sufficient and has room for improvement.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2015-182291 Summary of the invention

[0005] One embodiment of the liquid ejecting device according to the present invention is a liquid ejecting device for forming an image on a medium by ejecting liquid, and includes:

[0006] a first spray head that sprays liquid;

[0007] a first liquid supplying unit for supplying liquid to the first ejection head;

[0008] a first heating element, at least a portion of which is in contact with the first liquid supply portion;

[0009] a wiring substrate including a first surface, a second surface different from the first surface, and a first transmission wiring that transmits a first drive current supplied to the first heating element;

[0010] a first temperature indicating portion, which is disposed on the first surface;

[0011] The first temperature indicating portion indicates that the temperature of the first temperature indicating portion is less than a first threshold value in a first state, and indicates that the temperature of the first temperature indicating portion is greater than the first threshold value in a second state, and the first state and the second state change in a reversible manner.

[0012] At least a portion of the first temperature indicating portion overlaps with at least a portion of the first transfer wiring in a normal direction of the wiring substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A diagram showing the functional structure of a liquid ejecting device.

[0014] Figure 2 This is a diagram for explaining the schematic structure of the ejection portion.

[0015] Figure 3 : is a diagram showing an example of the signal waveforms of the drive signals COMA and COMB.

[0016] Figure 4 : is a diagram showing an example of the waveform of the drive signal VOUT.

[0017] Figure 5 A diagram showing the structure of a drive signal selection circuit.

[0018] Figure 6 A diagram showing an example of decoded content in a decoder.

[0019] Figure 7 A diagram showing the structure of a selection circuit.

[0020] Figure 8 This is a diagram for explaining the operation of the drive signal selection circuit.

[0021] Fig. 9 A diagram showing the structure of the liquid ejecting device when the liquid ejecting device is viewed from the side.

[0022] Fig.10 It is a side view showing the structure of the printing section of the liquid ejecting device.

[0023] Fig.11 It is a front view showing the structure of the printing section of the liquid ejecting device.

[0024] Fig.12 It is a perspective view showing the structure of the printing section of the liquid ejecting device.

[0025] Fig.13 A diagram showing an example of a cross-sectional structure of a heating control substrate.

[0026] Fig.14 2 is a diagram showing an example of a wiring pattern provided on the layer 231 .

[0027] Fig.15 2 is a diagram showing an example of a wiring pattern provided on the layer 232 .

[0028] Fig.16 2 is a diagram showing an example of a wiring pattern provided on the layer 233 .

[0029] Fig.17 This is a diagram showing an example of the structure of the surface 211 of the heating control substrate. DETAILED DESCRIPTION

[0030] Hereinafter, preferred embodiments of the present invention will be described using the accompanying drawings. The accompanying drawings used are for convenience of description. In addition, the embodiments described below do not improperly limit the contents of the present invention as described in the claims. In addition, the entire contents of the structures described below are not necessarily the necessary components of the present invention.

[0031] In addition, the liquid ejection device involved in the present invention is a printing device that ejects ink onto a recording medium as an example of a liquid, and a so-called inkjet printer is cited as an example for explanation. In addition, the liquid ejection device is not limited to an inkjet printer, and for example, it can also be a liquid ejection device that ejects a color material used in the manufacture of a color filter of a liquid crystal display, etc., a liquid ejection device that ejects an electrode material used in the formation of an electrode of an organic EL (Electroluminescence) display, a surface light-emitting display, etc., a liquid ejection device that ejects a biological organic substance used in the manufacture of a biochip, etc.

[0032] 1. Functional structure of liquid ejection device

[0033] Figure 1 , is a diagram showing the functional structure 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 formed along a transport direction, and reciprocates along a main scanning direction intersecting the transport direction by a carriage equipped with a liquid ejection head 400 that ejects ink to the recording medium, thereby forming a desired image on the recording medium. In addition, the following case is used for explanation, that is, the liquid ejection device 1 in this embodiment is a so-called printing and dyeing printer that uses cloth as a recording medium and forms a desired image on the cloth. In addition, the recording medium used in the liquid ejection device 1 is not limited to cloth, and may also be, for example, paper.

[0034] like Figure 1 As shown, the liquid ejection device 1 includes a control unit 10 and a head unit 20 .

[0035] 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 .

[0036] A specific example of the operation of the control unit 10 is described. An image signal PDATA is input from an external device such as a host computer (not shown) to the main control circuit 100. The main control circuit 100 performs various signal processing such as image processing on the input image signal PDATA. Then, the main control circuit 100 outputs a transmission signal Tx including the signal subjected to the signal processing to the head unit 20.

[0037] In addition, the main control circuit 100 generates various control signals for controlling various parts of the liquid ejection device 1, such as a control signal for controlling the transport of the recording medium along the transport direction, or a control signal for controlling the movement of the slide along the main scanning direction described later, and outputs them to the corresponding structure.

[0038] In the power supply circuit 101, a commercial AC voltage AC is supplied from a commercial power source not shown in the figure. The power supply circuit 101 generates a voltage signal VHC of a predetermined voltage value by performing AC / DC conversion on the supplied commercial AC voltage AC. The voltage signal VHC is, for example, a DC voltage of 24V, and is supplied to the head unit 20. In addition, the power supply circuit 101 can also generate a DC voltage of a voltage value such as 42V, 7.5V, 5V, 3.3V, etc. according to the supplied commercial AC voltage AC. The various DC voltages generated by the power supply circuit 101 are used in the power supply voltage of each structure of the liquid ejection device 1. That is, the power supply circuit 101 generates a DC voltage used in the power supply voltage of each structure of the liquid ejection device 1 according to the commercial AC voltage AC supplied to the liquid ejection device 1, and supplies it to each part of the liquid ejection device 1. In addition, the power supply circuit 101 may have a plurality of AC / DC conversion circuits for generating various DC voltages, or may convert the voltage value of the DC voltage generated in one AC / DC conversion by a DC / DC conversion circuit to generate DC voltages of a plurality of voltage values. Here, in the following description, the current flowing based on the voltage signal VHC output by the power supply circuit 101 is sometimes referred to as the heating current Ihc. That is, the liquid ejection device 1 has a power supply circuit 101 that outputs the heating current Ihc.

[0039] 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. Thus, the control unit 10 controls the operation of the head unit 20.

[0040] 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 heating units 700-1 to 700-m, and switches SW-1 to SW-m. The head unit 20 controls the discharge timing of ink and the discharge amount of the ink based on the transmission signal Tx output by the control unit 10. Thus, a desired image can be formed on a recording medium.

[0041] Here, there is the following situation, that is, when the driving circuits 300-1 to 300-n all have the same structure and do not need to be distinguished, they are simply referred to as the driving circuit 300, when the liquid ejection heads 400-1 to 400-n all have the same structure and do not need to be distinguished, they are simply referred to as the liquid ejection head 400, when the ink heating parts 700-1 to 700-m all have the same structure and do not need to be distinguished, they are simply referred to as the ink heating part 700, and when the switches SW-1 to SW-m all have the same structure and do not need to be distinguished, they are simply referred to as the switch SW.

[0042] A specific example of the operation of the head unit 20 is described. The transmission signal Tx is input to the ejection control circuit 200 of the head unit 20. The ejection control circuit 200 generates a reception signal Rx indicating the reception of the transmission signal Tx by receiving the transmission signal Tx, and outputs the reception signal Rx to the main control circuit 100. Such transmission signal Tx and reception signal Rx can use a differential signal of LVDS (Low Voltage Differential Signaling) method from the viewpoint of enabling high-speed communication with the control unit 10. In addition, the transmission signal Tx and reception signal Rx are not limited to electrical signals, and can be optical signals, or both electrical signals and optical signals can be used.

[0043] Furthermore, the discharge control circuit 200 generates a clock signal SCK, print data signals SI1 to SIn, latch signals LAT1 to LATn, conversion signals CH1 to CHn, and basic drive signals dA1 to dAn and dB1 to dBn based on the input transmission signal Tx.

[0044] The basic driving signals dA1 to dAn and dB1 to dBn outputted from the discharge control circuit 200 are inputted to the driving circuits 300 - 1 to 300 - n.

[0045] The driving circuit 300-1 includes a driving signal output circuit 310 and a reference voltage signal output circuit 320. The basic driving signals dA1 and dB1 outputted by the ejection control circuit 200 are inputted into the driving signal output circuit 310 of the driving circuit 300-1. After the inputted basic driving signal dA1 is subjected to digital / analog conversion, the driving signal output circuit 310 generates the driving signal COMA1 by performing a D-class amplification on the converted analog signal, and after the inputted basic driving signal dB1 is subjected to digital / analog conversion, the driving signal COMB1 is generated by performing a D-class amplification on the converted analog signal. That is, the driving signal output circuit 310 includes two D-class amplifier circuits, namely, a D-class amplifier circuit for generating the driving signal COMA1 based on the basic driving signal dA1 and a D-class amplifier circuit for generating the driving signal COMB1 based on the basic driving signal dB1. Moreover, the driving signal output circuit 310 included in the driving circuit 300 outputs the generated driving signals COMA1 and COMB1 to the liquid ejection head 400-1. In such a driving signal output circuit 310 , a class A amplifier circuit, a class B amplifier circuit, or a class AB amplifier circuit may be included instead of or in addition to the class D amplifier circuit.

[0046] The reference voltage signal output circuit 320 of the driving 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 a ground potential signal or a DC voltage signal with a voltage value of 5.5V or 6V, for example.

[0047] Here, as mentioned above, the drive circuits 300-1 to 300-n have the same structure. In the following description, the following situation is used for description, that is, the basic drive signals dAi and dBi are input into the drive circuit 300-i (i=any one of 1 to n), and the drive circuit 300-i generates the drive signals COMAi, COMBi, and the reference voltage signal VBSi, and outputs them to the liquid ejection head 400-i.

[0048] The liquid ejection heads 400 - 1 to 400 - n include piezoelectric elements 60 driven based on drive signals COMA1 to COMAn and COMB1 to COMBn, and eject ink toward a recording medium by driving the piezoelectric elements 60 .

[0049] The liquid ejection head 400-1 has a drive signal selection circuit 420 and p ejection units 600. The clock signal SCK, the printing data signal SI1, the latch signal LAT1, and the conversion signal CH1 output by the ejection control circuit 200, and the drive signals COMA1, COMB1, and the reference voltage signal VBS1 output by the drive circuit 300-1 are input to the liquid ejection head 400-1. Moreover, the liquid ejection head 400-1 switches whether to supply the drive signals COMA1 and COMB1 to the piezoelectric element 60 at the timing specified by the input clock signal SCK, the printing data signal SI1, the latch signal LAT1, and the conversion signal CH1. Thus, the driving of the piezoelectric element 60 is controlled, and the amount of ink ejected from the ejection unit 600 including the piezoelectric element 60 is controlled.

[0050] Specifically, the drive signal selection circuit 420 of the liquid ejection head 400-1 is configured, for example, in a manner including an integrated circuit device. The drive signal selection circuit 420 of the liquid ejection head 400-1 is input with a printing data signal SI1, a latch signal LAT1, a conversion signal CH1, a clock signal SCK, and drive signals COMA1 and COMB1. Moreover, the drive signal selection circuit 420 generates a drive signal VOUT by selecting or not selecting the drive signals COMA1 and COMB1 according to the printing data signal SI1 at a timing specified by the latch signal LAT1 and the conversion 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.

[0051] The p ejection parts 600 included in the liquid ejection head 400-1 each include a piezoelectric element 60. The 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 parts 600. In addition, the other end of the piezoelectric element 60 included in each of the p ejection parts 600 is supplied with a reference voltage signal VBS1 output by the reference voltage signal output circuit 320 included in the drive circuit 300-1. Moreover, the piezoelectric element 60 included in the ejection part 600 is driven according to the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBS1 supplied to the other end. The amount of ink corresponding to the driving of the piezoelectric element 60 is ejected from the corresponding ejection part 600.

[0052] Here, as described above, the liquid ejection heads 400-1 to 400-n all have the same structure. That is, in the liquid ejection head 400-i, the printing data signal SIi, the latch signal LATi, the conversion signal CHi, the clock signal SCK, and the drive signals COMAi and COMBi are input. Moreover, the drive signal selection circuit 420 of the liquid ejection head 400-i generates the drive signal VOUT by selecting or not selecting the drive signals COMAi and COMBi based on the printing data signal SIi, the latch signal LATi, the conversion signal CHi, and the clock signal SCK. Moreover, 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 parts 600 of the liquid ejection head 400-i. In addition, the reference voltage signal VBSi is supplied to the other end of the piezoelectric element 60 included in each of the p ejection units 600 of the liquid ejection head 400-i. The piezoelectric element 60 included in the p ejection units 600 of the liquid ejection head 400-i is 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 the ink of the amount corresponding to the drive is ejected from the corresponding ejection unit 600.

[0053] The ink heating units 700 - 1 to 700 - m each include a heating unit 710 and a temperature detection unit 720 .

[0054] The heating section 710 of the ink heating section 700-1 is supplied with a voltage signal VHC via the switch SW-1. That is, the heating section 710 of the ink heating section 700-1 is supplied with a heating current Ihc-1 of the heating current Ihc based on the voltage signal VHC outputted from the power supply circuit 101 via the switch SW-1. Thus, the heating section 710 of the ink heating section 700-1 generates heat by the heating current Ihc-1. The temperature detection section 720 of the ink heating section 700-1 detects the temperature of the heating section 710 of the ink heating section 700-1 and outputs it to the temperature control circuit 500 as a temperature detection signal Tmp-1.

[0055] Similarly, in the heating section 710 of the ink heating section 700-j (j=any one of 1 to m), a heating current Ihc-j is supplied through the switch SW-j from the heating current Ihc based on the voltage signal VHC outputted from the power supply circuit 101. Thus, the heating section 710 of the ink heating section 700-j generates heat by the heating current Ihc-j. The temperature detection section 720 of the ink heating section 700-j detects the temperature of the heating section 710 of the ink heating section 700-j and outputs it to the temperature control circuit 500 as a temperature detection signal Tmp-j.

[0056] The temperature control circuit 500 receives the temperature detection signals Tmp-1 to Tmp-m outputted from the temperature detection units 720 included in the ink heating units 700-1 to 700-m, respectively. The temperature control circuit 500 generates switch control signals Sc-1 to Sc-m for controlling each of the switches SW-1 to SW-m based on the input temperature detection signals Tmp-1 to Tmp-m, and outputs the switch control signals Sc-1 to Sc-m to the corresponding switches SW-1 to SW-m.

[0057] Specifically, the temperature control circuit 500 detects the temperature of the heating portion 710 of the ink heating portion 700-1 based on the temperature detection signal Tmp-1 outputted by the temperature detection portion 720 of the ink heating portion 700-1. Furthermore, when the temperature of the heating portion 710 of the ink heating portion 700-1 is lower than the expected temperature, the temperature control circuit 500 generates a switch control signal Sc-1 for controlling the switch SW-1 so as to increase the current amount of the heating current Ihc-1 flowing through the switch SW-1, and outputs the switch control signal Sc-1 to the switch SW-1. On the other hand, when the temperature of the heating portion 710 of the ink heating portion 700-1 is higher than the expected temperature, the temperature control circuit 500 generates a switch control signal Sc-1 for controlling the switch SW-1 so as to decrease the current amount of the heating current Ihc-1 flowing through the switch SW-1, and outputs the switch control signal Sc-1 to the switch SW-1. Thus, the temperature of the heating portion 710 of the ink heating portion 700-1 is controlled.

[0058] Similarly, the temperature control circuit 500 detects the temperature of the heating portion 710 of the ink heating portion 700-j based on the temperature detection signal Tmp-j outputted by the temperature detection portion 720 of the ink heating portion 700-j. Furthermore, when the temperature of the heating portion 710 of the ink heating portion 700-j is lower than the expected temperature, the temperature control circuit 500 generates a switch control signal Sc-j for controlling the switch SW-j so as to increase the current amount of the heating current Ihc-j flowing through the switch SW-j, and outputs it to the switch SW-j. On the other hand, when the temperature of the heating portion 710 of the ink heating portion 700-j is higher than the expected temperature, the temperature control circuit 500 generates a switch control signal Sc-j for controlling the switch SW-j so as to decrease the current amount of the heating current Ihc-j flowing through the switch SW-j, and outputs it to the switch SW-j. Thus, the temperature of the heating portion 710 of the ink heating portion 700-j is controlled to a predetermined value.

[0059] Here, as switches SW-1 to SW-m, a bipolar transistor whose collector and emitter terminals can be controlled in accordance with the amount of current supplied to the base terminal, or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) whose drain and source terminals can be controlled in accordance with the amount of current supplied to the gate terminal can be used.

[0060] Here, in the following description, it is assumed that the temperature detection unit 720 of the ink heating unit 700 outputs the 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.

[0061] As described above, in the liquid ejection device 1 of the present embodiment, the control unit 10 controls the conveyance of the recording medium according to the input image signal PDATA, and generates and outputs the transmission signal Tx to the head unit 20. Moreover, 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 is ejected at a desired position on the recording medium, thereby forming a desired dot on the recording medium.

[0062] In addition, in the liquid ejection device 1 of the present 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 ink used in the liquid ejection device 1 has physical properties such as viscosity that change due to temperature. In the liquid ejection device 1 of the present embodiment, the temperature of the ink flowing inside the liquid ejection device 1 can be kept substantially constant by the temperature control circuit 500 and the ink heating units 700-1 to 700-m. As a result, the physical properties such as viscosity of the ink flowing inside the liquid ejection device 1 are stabilized, and as a result, the ejection accuracy of the ink in the liquid ejection device 1 can be improved.

[0063] 2. Structure and operation of the liquid ejection head

[0064] Next, the structure of the liquid ejection head 400 is described. Here, the following case is assumed for description, that is, when describing the structure of the liquid ejection head 400, the printing data signal SI among the printing data signals SI1 to SIn, the latch signal LAT among the latch signals LAT1 to LATn, the conversion signal CH among the conversion signals CH1 to CHn, the clock signal SCK, the drive signal COMA among the drive signals COMA1 to COMAn, the drive signal COMB among the drive signals COMB1 to COMBn, and the reference voltage signal VBS among the reference voltage signals VBS1 to VBSn are input to the liquid ejection head 400.

[0065] First, the structure of the p ejecting sections 600 included in the liquid ejecting head 400 will be described. Figure 2 , which is a diagram for explaining the schematic structure of one of the p ejecting sections 600. Figure 2 In FIG. 6 , in addition to the ejection portion 600 , a liquid reservoir 641 and a supply port 661 are also shown.

[0066] like Figure 2 As shown in FIG. 1 , the ejection unit 600 includes a piezoelectric element 60, a vibration plate 621, a cavity 631, and a nozzle plate 632. In addition, the piezoelectric element 60 includes a piezoelectric body 601 and electrodes 611 and 612. Moreover, the piezoelectric element 60 is configured by being located at a position where the piezoelectric body 601 is sandwiched between the electrodes 611 and 612. The piezoelectric element 60 configured in the above manner is driven in a manner such that the central portion is displaced in the up-down direction according to the potential difference between the voltage supplied to the electrode 611 and the voltage supplied to the electrode 612.

[0067] Specifically, the driving signal VOUT based on the driving signals COMA and COMB is supplied to the electrode 611 of the piezoelectric element 60, and the reference voltage signal VBS is supplied to the electrode 612 of the piezoelectric element 60. Moreover, the voltage value of the driving signal VOUT supplied to the electrode 611 changes, thereby changing the potential difference between the electrode 611 supplied with the driving signal VOUT and the electrode 612 supplied with the reference voltage signal VBS. As a result, the piezoelectric element 60 is driven in a manner that the central portion is displaced in the up-down direction.

[0068] The vibration plate 621 is located at Figure 2 In other words, the piezoelectric element 60 is formed below the vibration plate 621. Figure 2 Such a vibration plate 621 is deformed in the vertical direction as the piezoelectric element 60 is driven in the vertical direction.

[0069] The cavity 631 is located at the vibrating plate 621. Figure 2 . In the cavity 631, ink is supplied from the reservoir 641 commonly provided at the plurality of ejection portions 600. In addition, ink stored in an ink container (not shown) is introduced into the reservoir 641 via the supply port 661. That is, the ink stored in the ink container is branched and supplied to the interior of the cavity 631 through the reservoir 641. Thus, the interior of the cavity 631 is filled with ink. The internal volume of such a cavity 631 expands or contracts with the displacement of the vibration plate 621 in the up-and-down direction. That is, the vibration plate 621 functions as a diaphragm that changes the internal volume of the cavity 631, and the cavity 631 functions as a pressure chamber in which the pressure changes with the displacement of the vibration plate 621 in the up-and-down direction.

[0070] The nozzle 651 is formed on the nozzle plate 632. That is, the ejection unit 600 includes the nozzle 651. The nozzle 651 is an opening provided on the nozzle plate 632 and communicates with the cavity 631. When the internal volume of the cavity 631 changes, the ink filled in the cavity 631 is ejected from the nozzle 651 according to the change in the internal volume.

[0071] In the ejection unit 600 configured as described above, when the piezoelectric element 60 is driven to bend upward, the vibration plate 621 is displaced upward. As a result, the internal volume of the cavity 631 is expanded, and as a result, the 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. As a result, the internal volume of the cavity 631 is reduced, and as a result, the amount of ink corresponding to the reduction degree of the internal volume of the cavity 631 is ejected from the nozzle 651.

[0072] The piezoelectric element 60 is not limited to a structure that can be driven by being supplied with a driving signal VOUT corresponding to the driving signals COMA and COMB and can eject ink from the nozzle 651 by being driven. Figure 2 The structure shown.

[0073] Next, an example of the signal waveform of the drive signal VOUT output by the drive signal selection circuit 420 is described based on an example of the signal waveform of the drive signals COMA and COMB output by the drive signal output circuit 310 and the drive signals COMA and COMB.

[0074] Figure 3 , which is a diagram showing an example of the signal waveforms of the drive signals COMA and COMB. Figure 3 As shown in FIG. 1 , the driving signal COMA includes a trapezoidal waveform Adp1 configured in a period T1 from the rise of the latch signal LAT to the rise of the conversion signal CH, and a trapezoidal waveform Adp2 configured in a period T2 from the rise of the conversion signal CH to the rise of the latch signal LAT. 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 portion 600 corresponding to the 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 portion 600 corresponding to the piezoelectric element 60.

[0075] The driving signal COMB includes a trapezoidal waveform Bdp1 configured in a period T1, and a trapezoidal waveform Bdp2 configured in a period T2. Moreover, when the trapezoidal waveform Bdp1 is supplied to one end of the piezoelectric element 60, the ink is not ejected from the ejection portion 600 corresponding to the piezoelectric element 60. The trapezoidal waveform Bdp1 is a signal waveform for preventing the increase of the viscosity of the ink by vibrating the ink near the nozzle opening portion of the ejection portion 600. In addition, 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 portion 600 corresponding to the piezoelectric element 60, similarly to the case where the trapezoidal waveform Adp1 is supplied.

[0076] Here, the trapezoidal waveforms Adp1, Adp2, Bdp1, and Bdp2 are common signal waveforms whose voltages at their respective start timings and end timings are all voltage Vc. That is, the trapezoidal waveforms Adp1, Adp2, Bdp1, and Bdp2 start at voltage Vc and end at voltage Vc, respectively.

[0077] 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, the amount of the predetermined amount of ink ejected from the ejection portion 600 corresponding to the piezoelectric element 60 is referred to as a small amount, and when the trapezoidal waveform Adp2 is supplied to one end of the piezoelectric element 60, the amount of ink ejected from the ejection portion 600 corresponding to the piezoelectric element 60 is referred to as a medium amount. In addition, when the trapezoidal waveform Bdp1 is supplied to one end of the piezoelectric element 60, the action of vibrating the ink near the nozzle opening of the ejection portion 600 corresponding to the piezoelectric element 60 to prevent the increase of the ink viscosity is referred to as a micro vibration BSD.

[0078] In addition, although Figure 3 , the trapezoidal waveform Adp1 and the trapezoidal waveform Bdp2 are shown as signal waveforms of the same shape, but the trapezoidal waveform Adp1 and the trapezoidal waveform Bdp2 may be signal waveforms of different shapes. In addition, although the following description is given as follows, the description is not limited to the following case, in which a small amount of ink is ejected from the corresponding ejection portion 600 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. That is, the signal waveforms of the drive signals COMA and COMB are not limited to Figure 3 The signal waveforms of the shapes shown may be a combination of various waveforms depending on the properties of the ink to be ejected, the material of the recording medium, and the like.

[0079] Furthermore, the driving circuits 300 - 1 to 300 - n may output signal waveforms of different shapes. That is, the driving signals COMA1 to COMAn may include signal waveforms that are different from each other, and the driving signals COMB1 to COMBn may include signal waveforms that are different from each other.

[0080] Figure 4 2 is a diagram showing an example of the waveform of the driving signal VOUT corresponding to the “large dot LD”, “medium dot MD”, “small dot SD”, and “micro vibration BSD” formed on the recording medium.

[0081] like Figure 4 As shown in FIG. 1 , the driving signal VOUT for forming a "large dot LD" on the recording medium is a signal waveform that makes the trapezoidal waveform Adp1 configured in the period T1 and the trapezoidal waveform Adp2 configured in the period T2 continuous. When the driving signal VOUT is supplied to one end of the piezoelectric element 60, a small amount of ink and a medium amount of ink are ejected from the ejection portion 600 corresponding to the piezoelectric element 60. Then, the respective inks are ejected onto the recording medium and merged, thereby forming a large dot LD on the recording medium.

[0082] The driving signal VOUT for forming the "midpoint MD" on the recording medium is a signal waveform that makes the trapezoidal waveform Adp1 configured in the period T1 and the trapezoidal waveform Bdp2 configured in the period T2 continuous. When the driving signal VOUT is supplied to one end of the piezoelectric element 60, two small amounts of ink are ejected from the ejection portion 600 corresponding to the piezoelectric element 60. Then, the respective inks are ejected onto the recording medium and merged, thereby forming a midpoint MD smaller than the large dot LD on the recording medium.

[0083] The driving signal VOUT for forming a "small dot SD" on the recording medium is a signal waveform that makes the trapezoidal waveform Adp1 configured in the period T1 and the waveform configured in the period T2 with a voltage value of the voltage Vc and fixed continuous. When the driving signal VOUT is supplied to one end of the piezoelectric element 60, a small amount of ink is ejected once from the ejection portion 600 corresponding to the piezoelectric element 60. Then, the ejected ink falls on the recording medium, thereby forming a small dot SD smaller than the midpoint MD on the recording medium.

[0084] The driving signal VOUT corresponding to the "micro-vibration BSD" becomes a signal waveform that makes the trapezoidal waveform Bdp1 configured in the period T1 and the waveform configured in the period T2 with a voltage value of the voltage Vc and fixed continuous. When the driving signal VOUT is supplied to one end of the piezoelectric element 60, only the ink near the nozzle opening of the ejection part 600 corresponding to the piezoelectric element 60 vibrates, and the ink is not ejected from the ejection part 600. Therefore, the ink does not land on the recording medium, and no dots are formed on the recording medium.

[0085] Here, among the waveforms whose voltage value is fixed at voltage Vc included in the driving signal VOUT, there is included a waveform, namely, a waveform formed by a waveform whose voltage value is fixed at voltage Vc and is supplied to the piezoelectric element 60 just before and is maintained by the capacitance component of the piezoelectric element 60 when the driving signal selection circuit 420 does not select any one of the trapezoidal waveforms Adp1, Adp2, Bdp1, and Bdp2 as the driving signal VOUT.

[0086] As described above, the liquid ejection device 1 of the present embodiment forms dots on the recording medium by combining the ink ejected during the period T1 and the ink ejected during the period T2 within the period T. The period T including the period T1 and the period T2 corresponds to the dot formation period for forming dots on the recording medium.

[0087] Next, the drive signal COMA and the drive signal COMB are selected or not selected to output Figure 4 The structure and operation of the drive signal selection circuit 420 for the drive signal VOUT shown in FIG. Figure 5 , which is a diagram showing the structure of the drive signal selection circuit 420. Figure 5 As shown, the drive signal selection circuit 420 includes a selection control circuit 430 and p selection circuits 440 .

[0088] The selection control circuit 430 is input with the print data signal SI, latch signal LAT, conversion signal CH, and clock signal SCK outputted from the ejection control circuit 200. In addition, the selection control circuit 430 is provided with a set of a shift register (S / R) 432, a latch circuit 434, and a decoder 436 corresponding to each 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.

[0089] The printing data signal SI is input to the selection control circuit 430 in synchronization with the clock signal SCK. In addition, the printing data signal SI includes 2-bit printing data [SIH, SIL] for selecting any one of "large dot LD", "middle dot MD", "small dot SD" and "micro vibration BSD" in a serial manner corresponding to each of the p ejection units 600. That is, the printing data signal SI is a 2p-bit signal. The printing data [SIH, SIL] included in the printing data signal SI is maintained in the p shift registers 432 corresponding to the p ejection units 600. Specifically, the p-stage shift registers 432 corresponding to the ejection units 600 are cascade-connected to each other, and the serially input printing data signal SI is sequentially transferred to the subsequent stage of the p-stage shift registers 432 connected in cascade according to the clock signal SCK. Then, the clock signal SCK is stopped by keeping the printing data [SIH, SIL] in the corresponding shift register 432. In other words, by stopping the supply of the clock signal SCK, the print data [SIH, SIL] included in the print data signal SI is held in the corresponding shift register 432. Figure 5 In order to distinguish the shift register 432, the shift registers 432 are marked as 1st stage, 2nd stage, ..., pth stage in order from the upstream side to which the printing data signal SI is input.

[0090] Each of the p latch circuits 434 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 . Figure 6 4 is a diagram showing an example of the decoding content in the decoder 436. The decoder 436 outputs the selection signals S1 and S2 according to the logic level of the print data [SIH, SIL] latched in each of the periods T1 and T2. For example, when the input print data [SIH, SIL] = [1, 0], the decoder 436 outputs the logic level of the selection signal S1 as the H level and the L level in the periods T1 and T2, and outputs the logic level of the selection signal S2 as the L level and the H level in the periods T1 and T2.

[0091] The selection signals S1 and S2 outputted from the decoder 436 are inputted to the selection circuit 440. The selection circuit 440 is provided corresponding to each of the p ejection units 600. That is, the drive signal selection circuit 420 has p selection circuits 440, which is the same number as the p ejection units 600. Figure 7 , which is a diagram showing the structure of the selection circuit 440 corresponding to one amount of the ejection unit 600. Figure 7As shown, the selection circuit 440 includes inverters 442a, 442b and transmission gates 444a, 444b as NOT circuits.

[0092] The selection signal S1 is input to the positive control terminal not marked with a circular mark in the transmission gate 444a, and after the logic level is inverted by the inverter 442a, it is also input to the negative control terminal marked with a circular mark in the transmission gate 444a. In addition, the drive signal COMA is supplied to the input terminal of the transmission gate 444a. Then, the transmission gate 444a sets the connection between the input terminal and the output terminal when the logic level of the selection signal S1 is at an H level, and sets the connection between the input terminal and the output terminal when the logic level of the selection signal S1 is at an L level. That is, the transmission gate 444a outputs the signal waveform included in the drive signal COMA from the output terminal when the logic level of the selection signal S1 is at an H level, and does not output the signal waveform included in the drive signal COMA from the output terminal when the logic level of the selection signal S1 is at an L level.

[0093] The selection signal S2 is input to the positive control terminal not marked with a circular mark in the transmission gate 444b, and after the logic level is inverted by the inverter 442b, it is also input to the negative control terminal marked with a circular mark in the transmission gate 444b. In addition, the drive signal COMB is supplied to the input terminal of the transmission gate 444b. Then, the transmission gate 444b sets the connection between the input terminal and the output terminal when the logic level of the selection signal S2 is at an H level, and sets the connection between the input terminal and the output terminal when the logic level of the selection signal S2 is at an L level. That is, the transmission gate 444b outputs the signal waveform included in the drive signal COMB from the output terminal when the logic level of the selection signal S2 is at an H level, and does not output the signal waveform included in the drive signal COMB from the output terminal when the logic level of the selection signal S2 is at an L level.

[0094] The output terminals of the transmission gates 444a and 444b configured as described above are connected in common in the selection circuit 440. The drive signal selection circuit 420 outputs the signal at the output terminals of the transmission gates 444a and 444b connected in common in the selection circuit 440 as the drive signal VOUT.

[0095] Here, use Figure 8 The operation of the drive signal selection circuit 420 will be described. Figure 8: is a diagram for explaining the operation of the drive signal selection circuit 420. The printing data signal SI is serially input in synchronization with the clock signal SCK. Then, the printing data signal SI is sequentially transferred in the p shift registers 432 corresponding to the p ejection units 600 in synchronization with the clock signal SCK. Thereafter, when the input of the clock signal SCK is stopped, the printing data [SIH, SIL] corresponding to each of the p ejection units 600 is retained in the shift register 432. In addition, the printing data signal SI is input in the order corresponding to the ejection units 600 of the p-level, ..., 2-level, and 1-level of the shift register 432.

[0096] Then, when the latch signal LAT rises, the latch circuit 434 latches the printing data [SIH, SIL] held in the shift register 432 at the same time. Figure 8 LT1, LT2, ..., LTp shown in the figure represent the printing data [SIH, SIL] latched by the latch circuits 434 corresponding to the shift registers 432 of the 1st, 2nd, ..., pth stages.

[0097] The decoder 436 generates the dot size specified by the latched print data [SIH, SIL] in accordance with the dot size specified by the latched print data [SIH, SIL]. Figure 6 Then, the selection circuit 440 selects or deselects the signal waveforms included in the drive signals COMA and COMB according to the logic levels of the selection signals S1 and S2 output by the decoder 436, thereby generating the drive signal VOUT.

[0098] Specifically, when the print data [SIH, SIL] = [1, 1] is input to the decoder 436, the decoder 436 sets the logic level of the selection signal S1 to the H, H level during the periods T1 and T2, and sets the logic level of the selection signal S2 to the L, L level during the periods T1 and T2. As a result, the selection circuit 440 selects the trapezoidal waveform Adp1 during the period T1, and selects the trapezoidal waveform Adp2 during the period T2. As a result, the drive signal selection circuit 420 outputs the same Figure 4 The “large dot LD” shown corresponds to the driving signal VOUT.

[0099] Furthermore, when the print data [SIH, SIL] = [1, 0] is input to the decoder 436, the decoder 436 sets the logic level of the selection signal S1 to the H level and the L level in the periods T1 and T2, and sets the logic level of the selection signal S2 to the L level and the H level in the periods T1 and T2. As a result, the selection circuit 440 selects the trapezoidal waveform Adp1 in the period T1 and selects the trapezoidal waveform Bdp2 in the period T2. As a result, the drive signal selection circuit 420 outputs the same Figure 4 The “midpoint MD” shown corresponds to the driving signal VOUT.

[0100] Furthermore, when the print data [SIH, SIL] = [0, 1] is input to the decoder 436, the decoder 436 sets the logic level of the selection signal S1 to the H level and the L level in the periods T1 and T2, and sets the logic level of the selection signal S2 to the L level and the L level in the periods T1 and T2. As a result, the selection circuit 440 selects the trapezoidal waveform Adp1 in the period T1, and does not select any of the trapezoidal waveforms Adp2 and Bdp2 in the period T2. As a result, the drive signal selection circuit 420 outputs the same Figure 4 The “small dot SD” shown corresponds to the driving signal VOUT.

[0101] Furthermore, when the 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 the L, L level during the periods T1 and T2, and sets the logic level of the selection signal S2 to the H, L level during the periods T1 and T2. As a result, the selection circuit 440 selects the trapezoidal waveform Bdp1 during the period T1, and does not select any of the trapezoidal waveforms Adp2 and Bdp2 during the period T2. As a result, the drive signal selection circuit 420 outputs the same Figure 4 The “micro-vibration BSD” shown corresponds to the driving signal VOUT.

[0102] As described above, the drive signal selection circuit 420 selects or deselects the trapezoidal waveforms Adp1, Adp2 contained in the drive signal COMA and the trapezoidal waveforms Bdp1, Bdp2 contained in the drive signal COMB based on the input printing data signal SI, latch signal LAT, conversion signal CH and clock signal SCK, thereby generating a drive signal VOUT corresponding to the "large dot LD", "middle dot MD", "small dot SD" and "micro-vibration BSD" corresponding to each of the p ejection units 600, and outputs it to each of the p ejection units 600.

[0103] 3. Structure of liquid ejection device

[0104] Next, the structure of the liquid ejecting device 1 will be described. Fig. 9 , which is a diagram showing the structure of the liquid ejecting device 1 when the liquid ejecting device 1 is viewed from the side. Fig. 9 As shown, the liquid ejection device 1 includes: an unwinding section 3 for unwinding a medium P serving as a recording medium, a supporting section 4 for supporting the unwinding medium P, a conveying section 5 for conveying the medium P supported on the supporting section 4, a printing section 6 for printing on the medium P conveyed by the conveying section 5, and a control section 2 for controlling the operation of each section of the liquid ejection device 1 including the unwinding section 3, the supporting section 4, the conveying section 5 and the printing section 6.

[0105] Here, in the following description, the width direction of the liquid ejection device 1 and the main scanning direction of the liquid ejection device 1 are referred to as the X direction, the depth direction of the liquid ejection device 1 are referred to as the Y direction, the height direction of the liquid ejection device 1 are referred to as the Z direction, and the direction in which the medium P is transported are referred to as the transport direction F. In addition, there is a case where the starting point side of the arrow mark indicating the X direction in the figure is referred to as the -X side, and the top side is referred to as the +X side, the starting point side of the arrow mark indicating the Y direction in the figure is referred to as the -Y side, and the top side is referred to as the +Y side, and the starting point side of the arrow mark indicating the Z direction in the figure is referred to as the -Z side, and the top side is referred to as the +Z side. In addition, although the following description is made on the assumption that the X direction, the Y direction, and the Z direction are orthogonal to each other, the various structures of the liquid ejection device 1 are not limited to the case where they are arranged orthogonally.

[0106] The control unit 2 generates various signals for controlling various structures of the liquid ejection device 1 and outputs them to the corresponding structures. Such a control unit 2 includes the control unit 10 described above. Moreover, the control unit 2 is arranged on the inner side of the housing of the liquid ejection device 1, for example, near an unillustrated connector of an unillustrated cable for transmitting an image signal PDATA input from an external device, near an unillustrated user interface to which operation information of the liquid ejection device 1 implemented by a user is input, near an unillustrated connector of an unillustrated cable for transmitting a commercial AC voltage AC supplied from a commercial power supply, etc. In addition, the control unit 2 is not limited to being composed of one substrate, and can also be composed of a plurality of substrates.

[0107] The unwinding unit 3 includes a holding member 31. The holding member 31 rotatably holds a roll body 32 on which the medium P is wound. The roll body 32 is rotated in one direction by the control of the control unit 2. Thus, the medium P wound on the roll body 32 is unwound and unwound on the support unit 4.

[0108] The support portion 4 unwinds the roll body 32 and supports the medium P, and forms a conveying path for conveying the medium P. Specifically, the support portion 4 includes a first support portion 41, a second support portion 42, and a third support portion 43. The first support portion 41 supports the medium P unwound from the unwinding portion 3, and guides the medium P toward the second support portion 42. The second support portion 42 supports the medium P when the printing process is executed. The third support portion 43 supports the medium P after the printing process is executed, and guides the medium P toward the downstream of the conveying direction F.

[0109] The conveying unit 5 conveys the medium P supported on the supporting unit 4 along the conveying path. The conveying unit 5 includes a conveying motor 51, a conveying roller 52, and a driven roller 53. The conveying motor 51 is rotationally driven by the control of the control unit 2. The conveying roller 52 is located on the +Z side of the conveying path of the medium P, and rotates according to the rotational drive of the conveying motor 51. The driven roller 53 is located on the -Z side of the conveying path of the medium P, and clamps the medium P conveyed along the conveying path together with the conveying roller 52. Moreover, when the conveying motor 51 is rotationally driven by the control of the control unit 2, the conveying roller 52 rotates, so that the medium P clamped by the conveying roller 52 and the driven roller 53 is conveyed along the conveying direction F.

[0110] 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. Fig.10 2 is a side view showing the structure of the printing unit 6 of the liquid ejecting device 1 . Fig.11 2 is a front view showing the structure of the printing unit 6 of the liquid ejecting device 1 . Fig.12 2 is a perspective view showing the structure of the printing unit 6 of the liquid ejecting device 1. Fig.10 , Fig.11 ,as well as Fig.12 As shown, the printing unit 6 includes a carriage 71 , a moving mechanism 61 , a guide member 62 , and a housing 81 .

[0111] The carriage 71 includes a carriage body 72 and a carriage cover 73. The carriage body 72 has a substantially L-shaped cross section when the carriage 71 is viewed along the X direction. The carriage cover 73 is provided so as to be detachable from the carriage body 72. Furthermore, by attaching the carriage cover 73 to the carriage body 72, a closed space is formed in the carriage 71. The carriage 71 is provided so as to be reciprocable along the X direction in a state where the side surface of the substantially L-shaped carriage body 72 on the +Z side faces the medium P.

[0112] In a closed space of the carriage 71 constituted by the carriage body 72 and the carriage cover 73, the liquid ejection heads 400-1 to 400-4 and the ink sub-tanks 750-1 to 750-4 are provided.

[0113] The liquid ejection head 400 is mounted on the carriage 71 in such a manner that p nozzles 651 are located side by side along the Y direction and the nozzles 651 are exposed from the +Z side of the carriage body 72. Furthermore, the liquid ejection heads 400-1 to 400-4 are located at positions arranged in the order of the liquid ejection heads 400-1, 400-2, 400-3, and 400-4 from the -X side toward the +X side along the X direction. In addition, the number of the liquid ejection heads 400 included in the liquid ejection device 1 is not limited to four.

[0114] The ink sub-tanks 750-1 to 750-4 temporarily store ink supplied from an ink container (not shown) of the liquid ejection device 1 to the printing unit 6. Such ink sub-tanks 750-1 to 750-4 are provided, for example, according to the color of the ink used in the liquid ejection device 1. The ink stored in the ink sub-tanks 750-1 to 750-4 is supplied to the corresponding liquid ejection head 400, and ejected from the p ejection units 600 of the liquid ejection head 400. Here, in the liquid ejection device 1 of the present embodiment, the ink sub-tank 750-1 corresponds to the liquid ejection head 400-1, the ink sub-tank 750-2 corresponds to the liquid ejection head 400-2, the ink sub-tank 750-3 corresponds to the liquid ejection head 400-3, and the ink sub-tank 750-4 corresponds to the liquid ejection head 400-4. That is, the ink stored in the ink sub-tank 750-1 is supplied to the liquid ejection head 400-1 and ejected from the p ejection parts 600 of the liquid ejection head 400-1. The ink stored in the ink sub-tank 750-2 is supplied to the liquid ejection head 400-2 and ejected from the p ejection parts 600 of the liquid ejection head 400-2. The ink stored in the ink sub-tank 750-3 is supplied to the liquid ejection head 400-3 and ejected from the p ejection parts 600 of the liquid ejection head 400-3. The ink stored in the ink sub-tank 750-4 is supplied to the liquid ejection head 400-4 and ejected from the p ejection parts 600 of the liquid ejection head 400-4.

[0115] Such ink sub-tanks 750 - 1 to 750 - 4 are preferably arranged near the corresponding liquid ejection heads 400 . In the liquid ejection device 1 of the present embodiment, the ink sub-tank 750-1 is arranged near the liquid ejection head 400-1 and is arranged on the -X side of the liquid ejection head 400-1, the ink sub-tank 750-2 is arranged near the liquid ejection head 400-2 and is arranged on the +X side of the liquid ejection head 400-1 and the -X side of the liquid ejection head 400-2, the ink sub-tank 750-3 is arranged near the liquid ejection head 400-3 and is arranged on the +X side of the liquid ejection head 400-2 and the -X side of the liquid ejection head 400-3, and the ink sub-tank 750-4 is arranged near the liquid ejection head 400-4 and is arranged on the +X side of the liquid ejection head 400-3 and the corresponding -X side of the liquid ejection head 400-4.

[0116] Here, the ink sub-tanks 750-1 to 750-4 are all of the same structure, and when there is no need to distinguish them, they may be simply referred to as the ink sub-tanks 750. In addition, the number of ink sub-tanks 750 included in the liquid ejection device 1 is not limited to four, and may be set to three or less, or five or more, depending on the number of colors of ink used in the liquid ejection device 1 or the amount of ink used. Furthermore, although the liquid ejection device 1 of the present embodiment is described as having a one-to-one correspondence between the ink sub-tanks 750 and the liquid ejection head 400, one ink sub-tank 750 may supply ink to a plurality of liquid ejection heads 400, and a plurality of ink sub-tanks 750 may supply ink to one liquid ejection head 400.

[0117] The ink heating unit 700 is mounted on the side surface of each of the +X side and the side surface of the -X side of the ink sub-tank 750. That is, the liquid ejection device 1 of the present embodiment has eight ink heating units 700 corresponding to the ink sub-tanks 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. In addition, 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 based on the detection result. Thus, the temperature of the heating unit 710 of the ink heating unit 700 is controlled, and as a result, the temperature of the ink stored in the ink sub-tank 750 to which the ink heating unit 700 is mounted is controlled.

[0118] Here, in the following description, the ink heating unit 700 installed on the side surface of the -X side of the ink sub-tank 750-1 is equivalent to the aforementioned ink heating unit 700-1, the ink heating unit 700 installed on the side surface of the +X side of the ink sub-tank 750-1 is equivalent to the aforementioned ink heating unit 700-2, the ink heating unit 700 installed on the side surface of the -X side of the ink sub-tank 750-2 is equivalent to the aforementioned ink heating unit 700-3, and the ink heating unit 700 installed on the side surface of the +X side of the ink sub-tank 750-2 is equivalent to the aforementioned ink heating unit 700-3. The ink heating unit 700-4 is equivalent to the ink heating unit 700-5, the ink heating unit 700 installed on the side of the -X side of the ink sub-tank 750-3 is equivalent to the ink heating unit 700-6, the ink heating unit 700 installed on the side of the -X side of the ink sub-tank 750-4 is equivalent to the ink heating unit 700-7, and the ink heating unit 700 installed on the side of the +X side of the ink sub-tank 750-4 is equivalent to the ink heating unit 700-8. In addition, the number of ink heating units 700 installed on the ink sub-tank 750 is not limited to two, and may be one, or three or more. Further, the ink heating unit 700 may also be installed on the side of the +Y side, -Y side, -Z side, and +Z side of the ink sub-tank 750.

[0119] The guide member 62 extends in the X direction and supports the carriage 71 in a manner that allows reciprocal movement in the X direction. Specifically, the guide member 62 has a rail portion 63 extending in the X direction at the lower portion of the side surface on the +Y side. In addition, the carriage body 72 included in the carriage 71 has a carriage support portion 64 at the lower portion of the side surface on the -Y side. And, the carriage support portion 64 is slidably engaged with the rail portion 63, so that the carriage 71 is slidably supported on the guide member 62.

[0120] The moving mechanism 61 includes a motor (not shown). The moving mechanism 61 controls the forward and reverse rotation of the motor under the control of the control unit 2. The moving mechanism 61 converts the rotational force generated by the forward and reverse rotation of the motor into a moving force of the carriage 71 along the X direction. As a result, the carriage 71 reciprocates along the X direction.

[0121] The housing 81 includes a closed space in a substantially rectangular parallelepiped shape. In the closed space of the housing 81, the ejection control substrate 21, the heating control substrate 22, and the drive circuit substrates 30-1 to 30-4 are accommodated. Moreover, the end of the housing 81 on the +Y side is fixed to the end of the carriage body 72 on the -Y side. That is, the ejection control substrate 21, the heating control substrate 22, and the drive circuit substrates 30-1 to 30-4 are mounted on the carriage 71 via the housing 81. In addition, the so-called closed space of the housing 81 is not limited to a completely sealed space, and may be a space having an opening in a portion, or may be a space that can be opened and closed in a portion.

[0122] The ejection control circuit 200 described above is mounted on the ejection control substrate 21, and a connector 28 is mounted thereon. One or more cables 82 for electrically connecting the control unit 2 and the ejection control substrate 21 are connected to the connector 28. Thus, the transmission signal Tx outputted by the main control circuit 100 included in the control unit 10 of the control unit 2 is inputted to the ejection control circuit 200 mounted on the ejection control substrate 21.

[0123] The drive circuit substrates 30-1 to 30-4 are arranged side by side in an upright state along the X direction at the -Z side of the ejection control substrate 21. Specifically, the drive circuit substrates 30-1 to 30-4 are arranged in the order of the drive circuit substrates 30-1, 30-2, 30-3, and 30-4 from the -X side toward the +X side along the X direction. On such a drive circuit substrate 30-1, the aforementioned drive circuit 300-1 is mounted, on the drive circuit substrate 30-2, the aforementioned drive circuit 300-2 is mounted, on the drive circuit substrate 30-3, the aforementioned drive circuit 300-3 is mounted, and on the drive circuit substrate 30-4, the aforementioned drive circuit 300-4 is mounted. Here, the drive circuit substrates 30-1 to 30-4 are all of the same structure, and when there is no need to distinguish them, they may be simply referred to as the drive circuit substrate 30. In addition, it is assumed that the following case is used for description, that is, the drive circuit 300 is arranged on the drive circuit substrate 30.

[0124] The ejection control substrate 21 and the drive circuit substrate 30 are connected via a connector 24. As such a connector 24, for example, a BtoB (Board to Board) connector that directly connects the ejection control substrate 21 and each of the drive circuit substrates 30-1 to 30-4 can be used. Thus, the basic drive signals dA and dB generated by the ejection control circuit 200 mounted on the ejection control substrate 21 are input to the drive circuit 300 mounted on the drive circuit substrate 30.

[0125] Connectors 84 and 85 are provided at the end of the +Y side of the driving circuit substrate 30. In addition, the connecting substrate 74 is located at the -Z side of the liquid ejection head 400, and connectors 76 and 77 are provided on the surface of the -Z side of the connecting substrate 74, and a connector 75 is provided on the surface of the +Z side of the connecting substrate 74. Moreover, one end of a cable 86 is connected to the connector 84 of the driving circuit substrate 30, and the other end of the cable 86 is connected to the connector 76 provided on the connecting substrate 74, and one end of a cable 87 is connected to the connector 85 of the driving circuit substrate 30, and the other end of the cable 87 is connected to the connector 77 provided on the connecting substrate 74. Further, the connecting substrate 74 is electrically connected to the liquid ejection head 400 via the connector 75. That is, the driving circuit substrate 30 and the liquid ejection head 400 are electrically connected via the cables 86 and 87, the connecting substrate 74, and the connector 75. Thus, the driving signals COMA and COMB and the reference voltage signal VBS outputted by the driving circuit 300 provided on the driving circuit substrate 30 are supplied to the liquid ejection head 400 .

[0126] In addition, in the liquid ejection device 1 of the present embodiment, the clock signal SCK, latch signal LAT, conversion signal CH, and print data signal SI outputted from the ejection control circuit 200 mounted on the ejection control substrate 21 are also inputted to the drive circuit substrate 30 via the connector 24. Furthermore, the clock signal SCK, latch signal LAT, conversion signal CH, and print data signal SI inputted to the drive circuit substrate 30 are transmitted through the wiring pattern (not shown) and cables 86 and 87 provided on the drive circuit substrate 30, and are inputted to the liquid ejection head 400. That is, the drive circuit substrate 30 also functions as a relay substrate for transmitting the clock signal SCK, latch signal LAT, conversion signal CH, and print data signal SI to the liquid ejection head 400.

[0127] In this case, the drive signals COMA, COMB, and the reference voltage signal VBS are high voltage signals capable of driving the piezoelectric element 60, whereas the clock signal SCK, the latch signal LAT, the conversion signal CH, and the printing data signal SI are low voltage logic signals. In the liquid ejection device 1 of the present embodiment, the high voltage drive signals COMA, COMB, and the reference voltage signal VBS are transmitted through one of the cables 86 and 87, and the low voltage clock signal SCK, the latch signal LAT, the conversion signal CH, and the printing data signal SI are transmitted through the other of the cables 86 and 87. Thus, the possibility of superposition of the high voltage drive signals COMA, COMB, and the reference voltage signal VBS with the low voltage clock signal SCK, the latch signal LAT, the conversion signal CH, and the printing data signal SI is reduced.

[0128] Here, in the liquid ejection device 1 of the present embodiment, the following situation is used for explanation, that is, the driving circuit substrate 30-1 is arranged corresponding to the liquid ejection head 400-1, the driving circuit substrate 30-2 is arranged corresponding to the liquid ejection head 400-2, the driving circuit substrate 30-3 is arranged corresponding to the liquid ejection head 400-3, and the driving circuit substrate 30-4 is arranged corresponding to the liquid ejection head 400-4. That is, the driving signals COMA1, COMB1, and the reference voltage signal VBS1 output by the driving circuit 300-1 installed on the driving circuit substrate 30-1, and the clock signal SCK, latch signal LAT1, conversion signal CH1, and printing data signal SI1 transmitted in the driving circuit substrate 30-1 are input to the liquid ejection head 400-1, and the driving signals COMA2, COMB2, and the reference voltage signal VBS2 output by the driving circuit 300-2 installed on the driving circuit substrate 30-2, and the clock signal SCK, latch signal LAT2, conversion signal CH2, and printing data signal SI2 transmitted in the driving circuit substrate 30-2 are input to the liquid ejection head 400-2. The driving signals COMA3, COMB3, and reference voltage signal VBS3 output by the driving circuit 300-3 installed on the driving circuit substrate 30-3, and the clock signal SCK, latch signal LAT3, conversion signal CH3, and printing data signal SI3 transmitted in the driving circuit substrate 30-3 are input into the liquid ejection head 400-3, and the driving signals COMA4, COMB4, and reference voltage signal VBS4 output by the driving circuit 300-4 installed on the driving circuit substrate 30-4, and the clock signal SCK, latch signal LAT4, conversion signal CH4, and printing data signal SI4 transmitted in the driving circuit substrate 30-4 are input into the liquid ejection head 400-4.

[0129] Here, the number of the driving circuit substrates 30 of the liquid ejection device 1 is not limited to four, and may be three or less, or five or more. Furthermore, although in the liquid ejection device 1 of the present embodiment, the driving circuit substrates 30 and the liquid ejection heads 400 are described in one-to-one correspondence, a plurality of signals including the driving signals COMA and COMB output by one driving circuit substrate 30 may also be input to a plurality of liquid ejection heads 400, and a plurality of signals including the driving signals COMA and COMB output by a plurality of driving circuit substrates 30 may also be input to a single liquid ejection head 400.

[0130] The heating control substrate 22 is located on the -Z side of the ejection control substrate 21 and on the -Y side of the drive circuit substrates 30-1 to 30-4. In such a heating control substrate 22, the aforementioned temperature control circuit 500 and switches SW-1 to SW-8 are installed, and a connector 29 is provided. One or more cables 83 for electrically connecting the control unit 2 and the heating control substrate 22 are connected to the connector 29. Thus, the 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 substrate 22 via the cable 83. In addition, one end of eight cables 730 is connected to the heating control substrate 22. The other end of each of the eight cables 730 is connected to the ink heating units 700-1 to 700-8.

[0131] As described above, the heating control substrate 22 branches the voltage signal VHC input from the power supply circuit 101 in a manner corresponding to the ink heating units 700-1 to 700-8. Then, one of the branched voltage signals VHC is supplied to the ink heating unit 700-1 via the switch SW-1 and the cable 730, a different one of the branched voltage signals VHC is supplied to the ink heating unit 700-2 via the switch SW-2 and the cable 730, a different one of the branched voltage signals VHC is supplied to the ink heating unit 700-3 via the switch SW-3 and the cable 730, and a different one of the branched voltage signals VHC is supplied to the ink heating unit 700-4 via the switch SW-4 and the cable 730. A different one of the branched voltage signals VHC is supplied to the ink heating section 700-5 via switch SW-5 and cable 730, a different one of the branched voltage signals VHC is supplied to the ink heating section 700-6 via switch SW-6 and cable 730, a different one of the branched voltage signals VHC is supplied to the ink heating section 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 section 700-8 via switch SW-8 and cable 730.

[0132] That is, the heating control substrate 22 includes: a wiring pattern for transmitting a heating current Ihc-1 supplied to the heating portion 710 of the ink heating portion 700-1, a wiring pattern for transmitting a heating current Ihc-2 supplied to the heating portion 710 of the ink heating portion 700-2, a wiring pattern for transmitting a heating current Ihc-3 supplied to the heating portion 710 of the ink heating portion 700-3, and a wiring pattern for transmitting a heating current Ihc-4 supplied to the heating portion 710 of the ink heating portion 700-4. The wiring pattern includes a wiring pattern for transmitting a heating current Ihc-4, a wiring pattern for transmitting a heating current Ihc-5 supplied to a heating portion 710 possessed by an ink heating portion 700-5, a wiring pattern for transmitting a heating current Ihc-6 supplied to a heating portion 710 possessed by an ink heating portion 700-6, a wiring pattern for transmitting a heating current Ihc-7 supplied to a heating portion 710 possessed by an ink heating portion 700-7, and a wiring pattern for transmitting a heating current Ihc-8 supplied to a heating portion 710 possessed by an ink heating portion 700-8.

[0133] The heating currents Ihc-1 to Ihc-8 transmitted through the heating control substrate 22 are transmitted 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. Here, in the following description, the cable 730 that transmits the heating current Ihc-1 supplied to the heating section 710 of the ink heating section 700-1 is referred to as the cable 730-1, the cable 730 that transmits the heating current Ihc-2 supplied to the heating section 710 of the ink heating section 700-2 is referred to as the cable 730-2, the cable 730 that transmits the heating current Ihc-3 supplied to the heating section 710 of the ink heating section 700-3 is referred to as the cable 730-3, and the cable 730 that transmits the heating current Ihc-4 supplied to the heating section 710 of the ink heating section 700-4 is referred to as the cable 730-5. 0 is called cable 730-4, cable 730 that transmits heating current Ihc-5 supplied to heating section 710 of ink heating section 700-5 is called cable 730-5, cable 730 that transmits heating current Ihc-6 supplied to heating section 710 of ink heating section 700-6 is called cable 730-6, cable 730 that transmits heating current Ihc-7 supplied to heating section 710 of ink heating section 700-7 is called cable 730-7, and cable 730 that transmits heating current Ihc-8 supplied to heating section 710 of ink heating section 700-8 is called cable 730-8.

[0134] Furthermore, temperature detection signals Tmp-1 to Tmp-8 indicating the respective temperatures of the ink heating units 700-1 to 700-8 are input to the heating control substrate 22 via the cable 730. The temperature detection signals Tmp-1 to Tmp-8 input to the heating control substrate 22 are transmitted in the wiring pattern provided on the heating control substrate 22, and are input to the temperature control circuit 500. The temperature control circuit 500 generates switch control signals Sc-1 to Sc-8 corresponding to each of the input temperature detection signals Tmp-1 to Tmp-8, and outputs them to the corresponding switches SW-1 to SW-8. Thus, the current amount of the heating current Ihc-1 to Ihc-8 supplied to each of the ink heating units 700-1 to 700-8 is controlled, and the temperature of the heating unit 710 provided to each of the ink heating units 700-1 to 700-8 is controlled. As a result, the temperature of the ink stored in the ink sub-tank 750-1 to which the ink heating sections 700-1 and 700-2 are attached, the temperature of the ink stored in the ink sub-tank 750-2 to which the ink heating sections 700-3 and 700-4 are attached, the temperature of the ink stored in the ink sub-tank 750-3 to which the ink heating sections 700-5 and 700-6 are attached, and the temperature of the ink stored in the ink sub-tank 750-4 to which the ink heating sections 700-7 and 700-8 are attached are controlled.

[0135] The ink used in the liquid ejection device 1 has a fixed viscosity from the viewpoint of reducing the possibility of bleeding when ejected onto the medium P. In particular, in the case of a printing and dyeing printer using cloth or the like as the medium P, the possibility of bleeding when ejected onto the medium P is high, and therefore, a high-viscosity ink is used. However, when the viscosity of the ink increases, it becomes difficult to control the fine ejection of the ink, and as a result, the quality of the image formed on the medium P may be reduced.

[0136] In view of such a problem, in the liquid ejection device 1 of the present embodiment, the ink supplied to the liquid ejection device 1 is temporarily stored in the ink sub-tank 750 provided near the liquid ejection head 400, and the temperature of the ink stored in the ink sub-tank 750 is controlled by the ink heating unit 700, thereby controlling the viscosity of the ink supplied to the liquid ejection head 400. As a result, the possibility of a decrease in the ejection accuracy of the ink ejected from the liquid ejection head 400 is reduced, and the possibility of a decrease in the quality of the image formed on the medium P is also reduced.

[0137] Furthermore, the liquid ejection device 1 may also include a circulation path for circulating the ink between the ink sub-tank 750 whose temperature is controlled and the liquid ejection head 400 that ejects the ink. Even when the temperature of the ink stored in the controlled ink sub-tank 750 is controlled by the ink heating unit 700, the temperature of the ink may decrease in the supply path for supplying the ink from the ink sub-tank 750 to the liquid ejection head 400. In response to such a decrease in the temperature of the ink, the liquid ejection device 1 can control the temperature of the ink stored in the ink sub-tank 750 by including the circulation path for circulating the ink between the ink sub-tank 750 and the liquid ejection head 400, and further control the temperature of the ink circulating in the circulation path. As a result, the possibility of a decrease in the ejection accuracy of the ink ejected from the liquid ejection head 400 is further reduced, and the possibility of a decrease in the quality of the image formed on the medium P is also further reduced.

[0138] As described above, the liquid ejection device 1 of the present 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 sub-tank 750-1 that supplies ink to the liquid ejection head 400-1; an ink sub-tank 750-2 that supplies ink to the liquid ejection head 400-2; an ink sub-tank 750-3 that supplies ink to the liquid ejection head 400-3; an ink sub-tank 750-4 that supplies ink to the liquid ejection head 400-4; ink heating units 700-1 and 700-2 that are attached to the ink sub-tank 750-1 so that at least a portion of the ink heating units 700-1 and 700-2 are in contact with the ink sub-tank 750-1 by being attached to the ink sub-tank 750-2 so that at least a portion of the ink heating units 700-1 and 700-2 are in contact with the ink sub-tank 750-1 by being attached to the ink sub-tank 750-2 Ink heating parts 700-3 and 700-4 partially contact the ink sub-tank 750-2; ink heating parts 700-5 and 700-6 are attached to the ink sub-tank 750-3 so as to at least partially contact the ink sub-tank 750-3; ink heating parts 700-7 and 700-8 are attached to the ink sub-tank 750-4 so as to at least partially contact the ink sub-tank 750-4; a heating control substrate 22 including a wiring pattern for transmitting heating currents Ihc-1 to Ihc-8 supplied to the heating parts 710 respectively possessed by the ink heating parts 700-1 to 700-8; and a carriage 71 carrying the heating control substrate 22 and reciprocating along the X direction intersecting the conveying direction F in which the medium P is conveyed.

[0139] In the liquid ejection device 1 configured as described above, the temperature of the ink stored in the ink sub-tank 750 is controlled by controlling the temperature of the heating portion 710 of the ink heating portion 700 attached to the ink sub-tank 750. In this case, the temperature of the ink ejected from the liquid ejection head 400 can be controlled by positioning the ink sub-tank 750 near the liquid ejection head 400. As a result, the viscosity of the ink ejected from the liquid ejection head 400 can be controlled, and as a result, the possibility of a decrease in the ejection accuracy of the ink ejected from the liquid ejection head 400 is reduced. Furthermore, in the case where the liquid ejection device 1 has a circulation path for circulating the ink between the ink sub-tank 750 and the liquid ejection head 400, the temperature of the ink circulating between the ink sub-tank 750 and the liquid ejection head 400 can also be controlled, and the possibility of a decrease in the ejection accuracy of the ink ejected from the liquid ejection head 400 is further reduced.

[0140] Here, the structure of the heating control substrate 22 that transmits the heating current Ihc supplied to the heating section 710 of the ink heating section 700 in order to control the temperature of the ink stored in the ink sub-tank 750 will be described. Figure 13 to Figure 17 In the figure, mutually orthogonal x-direction, y-direction, and z-direction are shown. In addition, in the following description, there is a case where the starting point side of the arrow mark indicating the x-direction in the figure is referred to as the -x side, and the top side is referred to as the +x side, the starting point side of the arrow mark indicating the y-direction in the figure is referred to as the -y side, and the top side is referred to as the +y side, and the starting point side of the arrow mark indicating the z-direction in the figure is referred to as the -z side, and the top side is referred to as the +z side. Moreover, in the liquid ejection device 1 of the present embodiment, it is set Figure 13 to Figure 17 The x-direction, y-direction, and z-direction shown correspond to Figures 9 to 12 The description is made in the X direction, Y direction, and Z direction shown in FIG. Figure 13 to Figure 17 The x-direction shown is located along Figures 9 to 12 The X-direction position shown, Figure 13 to Figure 17 The y direction shown is located along Figures 9 to 12 The Y-direction position shown, Figure 13 to Figure 17 The z direction shown is located along Figures 9 to 12 The heating control substrate 22 is disposed in the housing 81 in the manner of the position in the Z direction shown. In addition, the arrangement of the heating control substrate 22 in the storage space of the housing 81 is not limited to this.

[0141] Fig.13 2 is a diagram showing an example of a cross-sectional structure of the heating control substrate 22. Fig.13As shown, the heating control substrate 22 includes a surface 211 and a surface 212 different from the surface 211. The surface 211 and the surface 212 are located facing each other along the z direction so that the surface 211 is on the -z side and the surface 212 is on the +z side.

[0142] The heating control substrate 22 includes layers 231 , 232 , 233 , a plurality of layers 240 , and layers 251 , 252 .

[0143] The layers 231, 232, and 233 are located between the surface 211 and the surface 212, and are arranged in the order of layer 231, layer 232, and layer 233 from the -z side toward the +z side along the z direction. On each of the layers 231, 232, and 233, there is provided a wiring pattern for transmitting a signal input to the heating control substrate 22, or a wiring pattern for electrically connecting various electronic components arranged on the heating control substrate 22. Each of the layers 231, 232, and 233 is a material with excellent conductivity for transmitting various signals, for example, including a wiring pattern formed by copper foil. That is, the layers 231, 232, and 233 are equivalent to a wiring layer on which a wiring pattern for transmitting various signals is provided on the heating control substrate 22. In other words, the heating control substrate 22 has a plurality of wiring layers including layers 231 , 232 , and 233 that are located between the surface 211 and the surface 212 and are provided with wiring patterns for transmitting signals.

[0144] The plurality of layers 240 are located between the layer 231 and the layer 232, and between the layer 232 and the layer 233 in the direction along the z direction. The plurality of layers 240 are equivalent to insulating layers that insulate the layers 231, 232, and 233 provided with wiring patterns from each other. Such a plurality of layers 240 are materials with excellent insulating properties, for example, epoxy glass formed by impregnating epoxy resin in glass fiber cloth. In other words, the heating control substrate 22 has a plurality of insulating layers for insulating the layers 231, 232, and 233 provided with wiring patterns from each other, which are located between the surface 211 and the surface 212.

[0145] The layer 251 is located on the -z side of the layer 231, and the layer 252 is located on the +z side of the layer 233. That is, the layer 251 is located at a position covering the surface of the -z side of the heating control substrate 22, and the layer 252 is located at a position covering the surface of the +z side of the heating control substrate 22. The layers 251 and 252 also function as protective layers for protecting the wiring patterns formed on the layers 231 and 233 from the outside of the heating control substrate 22. Such layers 251 and 252 are configured, for example, in a manner including a solder resist film or the like. That is, the heating control substrate 22 has a layer 251 and a layer 252, wherein the layer 251 is located at a position covering the surface of the -z side of the heating control substrate 22 and constitutes at least a portion of the surface 211 of the heating control substrate 22, and the layer 252 is located at a position covering the surface of the +z side of the heating control substrate 22 and constitutes at least a portion of the surface 212 of the heating control substrate 22.

[0146] As described above, the heating control substrate 22 of the present embodiment is a so-called multi-layer substrate including a surface 211 and a surface 212 different from the surface 211 and having a plurality of wiring layers between the surface 211 and the surface 212. The number of wiring layers of the heating control substrate 22 is not limited to Fig.13 An example is shown. That is, the heating control substrate 22 may include, in addition to the layers 231, 232, and 233, a wiring layer provided with a wiring pattern for transmitting a power supply voltage, a wiring layer provided with a wiring pattern for supplying a ground potential, a wiring layer provided with a wiring pattern for transmitting other signals, etc. Here, in the following description, there is a case where the case of observing the heating control substrate 22 from the -z side along the z direction is referred to as the case of the top view of the heating control substrate 22.

[0147] Next, a specific example of the wiring patterns provided on the layers 231 to 233 corresponding to the wiring layers will be described. Fig.14 2 is a diagram showing an example of a wiring pattern provided on the layer 231 . Fig.15 2 is a diagram showing an example of a wiring pattern provided on the layer 232 . Fig.16 2 is a diagram showing an example of a wiring pattern provided on layer 233. Figure 14 to Figure 16 As shown, the heating control substrate 22 is a multilayer substrate having a substantially rectangular shape including two sides facing each other along the x direction and two sides facing each other along the y direction, and includes wirings pih1 to pih5, wirings pt1 to pt8, wirings ps1 to ps8, wirings pc1 to pc8, and a plurality of wirings TM provided on a layer 231, wirings psc1 to pcs8 and wirings ptm1 to ptm8 provided on a layer 232, and wirings pih6 to pih10 provided on a layer 233. Figure 14 to Figure 16In FIG. 1 , the connector 29 mounted on the heating control board 22 , the temperature control circuit 500 , and the switches SW- 1 to SW- 8 , and one ends of the cables 730 - 1 to 730 - 8 mounted on the heating control board 22 are illustrated by dotted lines.

[0148] The plurality of wirings TM are electrically connected to terminals (not shown) of the temperature control circuit 500. Thus, various signals transmitted in the heating control substrate 22 are input to the temperature control circuit 500, and various signals output from the temperature control circuit 500 are transmitted in the heating control substrate 22 toward corresponding structures.

[0149] The wiring pih1 is a wiring pattern extending along the x direction, and an end portion on the +x side is connected to the connector 29 via a through hole or the like.

[0150] Wiring pih2 to pih5 are wiring patterns extending along the y direction, respectively, and the ends of the respective -y sides are connected to the wiring pih1. Specifically, for wiring pih2, the end on the -y side is connected to the wiring pih1, and extends toward the +y side along the y direction. Wiring pih3 is located on the +x side of wiring pih2, and the end on the -y side is connected to the wiring pih1, and extends toward the +y side along the y direction. Wiring pih4 is located on the +x side of wiring pih3, and the end on the -y side is connected to the wiring pih1, and extends toward the +y side along the y direction. Wiring pih5 is located on the +x side of wiring pih4, and the end on the -y side is connected to the wiring pih1, and extends toward the +y side along the y direction. That is, wirings pih2 to pih5 are arranged side by side in a manner that branches wiring pih1.

[0151] Wiring pc1 is located on the -x side of the end of the +y side of wiring pih2, and is electrically connected to wiring pih2 via switch SW-1. Wiring pc2 is located on the +x side of the end of the +y side of wiring pih2, and is electrically connected to wiring pih2 via switch SW-2. That is, at the end of the +y side of wiring pih2, one end of switch SW-1 and one end of switch SW-2 are connected, and the other end of switch SW-1 is connected to wiring pc1, and the other end of switch SW-2 is connected to wiring pc2. Moreover, one end of cable 730-1 is connected to wiring pc1, and one end of cable 730-2 is connected to wiring pc2.

[0152] Wiring pc3 is located at the -x side of the end of the +y side of wiring pih3, and is electrically connected to wiring pih3 via switch SW-3. Wiring pc4 is located at the +x side of the end of the +y side of wiring pih3, and is electrically connected to wiring pih3 via switch SW-4. That is, at the end of the +y side of wiring pih3, one end of switch SW-3 and one end of switch SW-4 are connected, and the other end of switch SW-3 is connected to wiring pc3, and the other end of switch SW-4 is connected to wiring pc4. Moreover, one end of cable 730-3 is connected to wiring pc3, and one end of cable 730-4 is connected to wiring pc4.

[0153] Wiring pc5 is located on the -x side of the end of the +y side of wiring pih4, and is electrically connected to wiring pih4 via switch SW-5. Wiring pc6 is located on the +x side of the end of the +y side of wiring pih4, and is electrically connected to wiring pih4 via switch SW-6. That is, at the end of the +y side of wiring pih4, one end of switch SW-5 and one end of switch SW-6 are connected, and the other end of switch SW-5 is connected to wiring pc5, and the other end of switch SW-6 is connected to wiring pc6. Moreover, one end of cable 730-5 is connected to wiring pc5, and one end of cable 730-6 is connected to wiring pc6.

[0154] Wiring pc7 is located on the -x side of the end of the +y side of wiring pih5, and is electrically connected to wiring pih5 via switch SW-7. Wiring pc8 is located on the +x side of the end of the +y side of wiring pih5, and is electrically connected to wiring pih5 via switch SW-8. That is, at the end of the +y side of wiring pih5, one end of switch SW-7 and one end of switch SW-8 are connected, and the other end of switch SW-7 is connected to wiring pc7, and the other end of switch SW-8 is connected to wiring pc8. Moreover, one end of cable 730-7 is connected to wiring pc7, and one end of cable 730-8 is connected to wiring pc8.

[0155] 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 directly connected to the heating control board 22 by welding or the like.

[0156] The switch SW-1 is also connected to the wiring ps1. The wiring ps1 is connected to one end of the wiring psc1 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring psc1 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the switch SW-1 and the temperature control circuit 500 are electrically connected via the wiring pcs1.

[0157] The switch SW-2 is also connected to the wiring ps2. The wiring ps2 is connected to one end of the wiring psc2 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring psc2 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the switch SW-2 and the temperature control circuit 500 are electrically connected via the wiring pcs2.

[0158] The switch SW-3 is also connected to the wiring ps3. The wiring ps3 is connected to one end of the wiring psc3 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring psc3 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the switch SW-3 and the temperature control circuit 500 are electrically connected via the wiring pcs3.

[0159] The switch SW-4 is also connected to the wiring ps4. The wiring ps4 is connected to one end of the wiring psc4 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring psc4 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the switch SW-4 and the temperature control circuit 500 are electrically connected via the wiring pcs4.

[0160] The switch SW-5 is also connected to the wiring ps5. The wiring ps5 is connected to one end of the wiring psc5 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring psc5 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the switch SW-5 and the temperature control circuit 500 are electrically connected via the wiring pcs5.

[0161] The switch SW-6 is also connected to the wiring ps6. The wiring ps6 is connected to one end of the wiring psc6 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring psc6 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the switch SW-6 and the temperature control circuit 500 are electrically connected via the wiring pcs6.

[0162] The switch SW-7 is also connected to the wiring ps7. The wiring ps7 is connected to one end of the wiring psc7 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring psc7 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the switch SW-7 and the temperature control circuit 500 are electrically connected via the wiring pcs7.

[0163] The switch SW-8 is also connected to the wiring ps8. The wiring ps8 is connected to one end of the wiring psc8 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring psc8 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the switch SW-8 and the temperature control circuit 500 are electrically connected via the wiring pcs8.

[0164] One end of the cable 730-1 is also connected to the wiring pt1. The wiring pt1 is connected to one end of the wiring ptm1 provided on the layer 232 via a through hole or the like not shown. The other end of the wiring ptm1 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole or the like not shown. That is, the cable 730-1 and the temperature control circuit 500 are electrically connected via the wiring ptm1.

[0165] 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 through hole not shown in the figure. The other end of the wiring ptm2 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the cable 730-2 and the temperature control circuit 500 are electrically connected via the wiring ptm2.

[0166] 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 through hole not shown in the figure. The other end of the wiring ptm3 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the cable 730-3 and the temperature control circuit 500 are electrically connected via the wiring ptm3.

[0167] One end of the cable 730-4 is also connected to the wiring pt4. The wiring pt4 is connected to one end of the wiring ptm4 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring ptm4 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the cable 730-4 and the temperature control circuit 500 are electrically connected via the wiring ptm4.

[0168] One end of the cable 730-5 is also connected to the wiring pt5. The wiring pt5 is connected to one end of the wiring ptm5 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring ptm5 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the cable 730-5 and the temperature control circuit 500 are electrically connected via the wiring ptm5.

[0169] One end of the cable 730-6 is also connected to the wiring pt6. The wiring pt6 is connected to one end of the wiring ptm6 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring ptm6 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the cable 730-6 and the temperature control circuit 500 are electrically connected via the wiring ptm6.

[0170] One end of the cable 730-7 is also connected to the wiring pt7. The wiring pt7 is connected to one end of the wiring ptm7 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring ptm7 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the cable 730-7 and the temperature control circuit 500 are electrically connected via the wiring ptm7.

[0171] One end of the cable 730-8 is also connected to the wiring pt8. The wiring pt8 is connected to one end of the wiring ptm8 provided on the layer 232 via a through hole not shown in the figure. The other end of the wiring ptm8 is connected to at least one of the plurality of wirings TM provided on the layer 231 via a through hole not shown in the figure. That is, the cable 730-8 and the temperature control circuit 500 are electrically connected via the wiring ptm8.

[0172] Wiring pih6 is a wiring pattern extending in the x direction, and its end on the +x side is connected to wiring pih1 provided on layer 231 via a through hole or the like. Wiring pih6 is located so as to at least partially overlap wiring pih1 in a plan view of the heating control substrate 22.

[0173] The wirings pih7 to pih10 are wiring patterns extending along the y direction, respectively, and the ends on the -y side of each of the wirings are connected to the wiring pih6.

[0174] Specifically, for wiring pih7, the end on the -y side is connected to wiring pih6 and extends toward the +y side along the y direction. Moreover, the end on the +y side of wiring pih7 is connected to wiring pih2 provided on layer 231 via a through hole or the like. At this time, wiring pih7 is located at a position where at least a portion overlaps with wiring pih2 when the heating control substrate 22 is viewed from above. Wiring pih8 is located on the +x side of wiring pih7, and the end on the -y side is connected to wiring pih6 and extends toward the +y side along the y direction. Moreover, the end on the +y side of wiring pih8 is connected to wiring pih3 provided on layer 231 via a through hole or the like. At this time, wiring pih8 is located at a position where at least a portion overlaps with wiring pih3 when the heating control substrate 22 is viewed from above. Wiring pih9 is located on the +x side of wiring pih8, and is connected to wiring pih6 through the end on the -y side, and extends toward the +y side along the y direction. Moreover, the end on the +y side of wiring pih9 is connected to wiring pih4 provided on layer 231 via a through hole or the like. At this time, wiring pih9 is located at a position where at least a portion overlaps with wiring pih4 when viewed from above the heating control substrate 22. Wiring pih10 is located on the +x side of wiring pih9, and is connected to wiring pih6 through the end on the -y side, and extends toward the +y side along the y direction. Moreover, the end on the +y side of wiring pih10 is connected to wiring pih5 provided on layer 231 via a through hole or the like. At this time, wiring pih10 is located at a position where at least a portion overlaps with wiring pih5 when viewed from above the heating control substrate 22.

[0175] That is, the wirings pih1 to pih5 provided on the layer 231 and the wirings pih6 to pih10 provided on the layer 233 are provided electrically in parallel and are located at positions where they at least partially overlap when viewed from above the heating control substrate 22 .

[0176] Here, various signals transmitted in the heating control substrate 22 and details of temperature control of the heating section 710 included in each of the ink heating sections 700 - 1 to 700 - 8 will be described.

[0177] The connector 29 to which the voltage signal VHC outputted from the power supply circuit 101 is inputted and the cable 730-1 connected to the ink heating unit 700-1 mounted on the ink sub-tank 750-1 are electrically connected via the wiring pih1 and the wiring pih6 provided on the layer 231, the wiring pih2 and the wiring pih7 provided on the layer 233, the switch SW-1, and the wiring pc1. That is, the heating current Ihc-1 of the heating current Ihc based on the voltage signal VHC outputted from the power supply circuit 101 is transmitted through the wiring pih1, the wiring pih6, the wiring pih2, and the wiring pih7, and is supplied to the heating unit 710 of the ink heating unit 700-1 via the switch SW-1, the wiring pc1, and the cable 730-1.

[0178] In addition, the 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 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 substrate 22 via the cable 730-1. Then, the temperature detection signal Tmp-1 is transmitted through the wiring pt1 and the wiring ptm1 provided in the heating control substrate 22, and is input to the temperature control circuit 500 via the wiring TM.

[0179] The temperature control circuit 500 generates and outputs a switch control signal Sc-1 corresponding to the input temperature detection signal Tmp-1. The switch control signal Sc-1 is input to the heating control substrate 22 via the wiring TM. The switch control signal Sc-1 is transmitted through the wiring psc1 and the wiring ps1 provided in the heating control substrate 22, and is input to the control terminal of the switch SW-1. Thus, the conduction state of the switch SW-1 is controlled, and the current amount of the heating current Ihc-1 supplied to the ink heating unit 700-1 is controlled. That is, the temperature of the heating unit 710 of the ink heating unit 700-1 that generates heat according to the current amount of the heating current Ihc-1 is controlled.

[0180] Similarly, the connector 29 to which the voltage signal VHC outputted from the power supply circuit 101 is inputted and the cable 730-2 connected to the ink heating unit 700-2 mounted on the ink sub-tank 750-1 are electrically connected via the wiring pih1 and the wiring pih6, the wiring pih2 and the wiring pih7, the switch SW-2, and the wiring pc2. Therefore, the heating current Ihc-2 is transmitted through the wiring pih1 and the wiring pih6, and the wiring pih2 and the wiring pih7, and is supplied to the heating unit 710 of the ink heating unit 700-2 via the switch SW-2, the wiring pc2, and the cable 730-2. In addition, the temperature detection unit 720 of the ink heating unit 700-2 outputs a temperature detection signal Tmp-2 based on the temperature of the heating unit 710. After the temperature detection signal Tmp-2 is input to the heating control substrate 22 via the cable 730-2, it is transmitted through the wiring pt2 and the wiring ptm2, and is input to the temperature control circuit 500 via the wiring TM. The temperature control circuit 500 outputs a switch control signal Sc-2 corresponding to the input temperature detection signal Tmp-2. After the switch control signal Sc-2 is input to the heating control substrate 22, it is transmitted through the wiring psc2 and the wiring ps2, and is input to the control terminal of the switch SW-2. Thus, the conduction state of the switch SW-2 is controlled, and the current amount of the heating current Ihc-2 supplied to the ink heating unit 700-2 is controlled. As a result, the temperature of the heating unit 710 of the ink heating unit 700-2 that generates heat according to the current amount of the heating current Ihc-2 is controlled.

[0181] Similarly, the connector 29 to which the voltage signal VHC outputted from the power supply circuit 101 is inputted and the cable 730-3 connected to the ink heating unit 700-3 mounted on the ink sub-tank 750-2 are electrically connected via the wiring pih1 and the wiring pih6, the wiring pih3 and the wiring pih8, the switch SW-3, and the wiring pc3. Therefore, the heating current Ihc-3 is transmitted through the wiring pih1 and the wiring pih6, and the wiring pih3 and the wiring pih8, and is supplied to the heating unit 710 of the ink heating unit 700-3 via the switch SW-3, the wiring pc3, and the cable 730-3. In addition, the temperature detection unit 720 of the ink heating unit 700-3 outputs a temperature detection signal Tmp-3 based on the temperature of the heating unit 710. After the temperature detection signal Tmp-3 is input to the heating control substrate 22 via the cable 730-3, it is transmitted through the wiring pt3 and the wiring ptm3, and is input to the temperature control circuit 500 via the wiring TM. The temperature control circuit 500 outputs a switch control signal Sc-3 corresponding to the input temperature detection signal Tmp-3. After the switch control signal Sc-3 is input to the heating control substrate 22, it is transmitted through the wiring psc3 and the wiring ps3, and is input to the control terminal of the switch SW-3. Thus, the conduction state of the switch SW-3 is controlled, and the current amount of the heating current Ihc-3 supplied to the ink heating unit 700-3 is controlled. As a result, the temperature of the heating unit 710 of the ink heating unit 700-3 that generates heat according to the current amount of the heating current Ihc-3 is controlled.

[0182] Similarly, the connector 29 to which the voltage signal VHC outputted from the power supply circuit 101 is inputted and the cable 730-4 connected to the ink heating unit 700-4 mounted on the ink sub-tank 750-2 are electrically connected via the wiring pih1 and the wiring pih6, the wiring pih3 and the wiring pih8, the switch SW-4, and the wiring pc4. Therefore, the heating current Ihc-4 is transmitted through the wiring pih1 and the wiring pih6, and the wiring pih3 and the wiring pih8, and is supplied to the heating unit 710 of the ink heating unit 700-4 via the switch SW-4, the wiring pc4, and the cable 730-4. In addition, the temperature detection unit 720 of the ink heating unit 700-4 outputs a temperature detection signal Tmp-4 based on the temperature of the heating unit 710. After the temperature detection signal Tmp-4 is input to the heating control substrate 22 via the cable 730-4, it is transmitted in the wiring pt4 and the wiring ptm4, and is input to the temperature control circuit 500 via the wiring TM. The temperature control circuit 500 outputs a switch control signal Sc-4 corresponding to the input temperature detection signal Tmp-4. After the switch control signal Sc-4 is input to the heating control substrate 22, it is transmitted in the wiring psc4 and the wiring ps4, and is input to the control terminal of the switch SW-4. Thus, the conduction state of the switch SW-4 is controlled, and the current amount of the heating current Ihc-4 supplied to the ink heating unit 700-4 is controlled. As a result, the temperature of the heating unit 710 of the ink heating unit 700-4 that generates heat according to the current amount of the heating current Ihc-4 is controlled.

[0183] Similarly, the connector 29 to which the voltage signal VHC outputted from the power supply circuit 101 is inputted and the cable 730-5 connected to the ink heating unit 700-5 mounted on the ink sub-tank 750-3 are electrically connected via the wiring pih1 and the wiring pih6, the wiring pih4 and the wiring pih9, the switch SW-5, and the wiring pc5. Therefore, the heating current Ihc-5 is transmitted through the wiring pih1 and the wiring pih6, and the wiring pih4 and the wiring pih9, and is supplied to the heating unit 710 of the ink heating unit 700-5 via the switch SW-5, the wiring pc5, and the cable 730-5. In addition, the temperature detection unit 720 of the ink heating unit 700-5 outputs a temperature detection signal Tmp-5 based on the temperature of the heating unit 710. After the temperature detection signal Tmp-5 is input to the heating control substrate 22 via the cable 730-5, it is transmitted in the wiring pt5 and the wiring ptm5, and is input to the temperature control circuit 500 via the wiring TM. The temperature control circuit 500 outputs a switch control signal Sc-5 corresponding to the input temperature detection signal Tmp-5. After the switch control signal Sc-5 is input to the heating control substrate 22, it is transmitted in the wiring psc5 and the wiring ps5, and is input to the control terminal of the switch SW-5. Thus, the conduction state of the switch SW-5 is controlled, and the current amount of the heating current Ihc-5 supplied to the ink heating unit 700-5 is controlled. As a result, the temperature of the heating unit 710 of the ink heating unit 700-5 that generates heat according to the current amount of the heating current Ihc-5 is controlled.

[0184] Similarly, the connector 29 to which the voltage signal VHC outputted from the power supply circuit 101 is inputted and the cable 730-6 connected to the ink heating unit 700-6 mounted on the ink sub-tank 750-3 are electrically connected via the wiring pih1 and the wiring pih6, the wiring pih4 and the wiring pih9, the switch SW-6, and the wiring pc6. Therefore, the heating current Ihc-6 is transmitted through the wiring pih1 and the wiring pih6, and the wiring pih4 and the wiring pih9, and is supplied to the heating unit 710 of the ink heating unit 700-6 via the switch SW-6, the wiring pc6, and the cable 730-6. In addition, the temperature detection unit 720 of the ink heating unit 700-6 outputs a temperature detection signal Tmp-6 based on the temperature of the heating unit 710. After the temperature detection signal Tmp-6 is input to the heating control substrate 22 via the cable 730-6, it is transmitted in the wiring pt6 and the wiring ptm6, and is input to the temperature control circuit 500 via the wiring TM. The temperature control circuit 500 outputs a switch control signal Sc-6 corresponding to the input temperature detection signal Tmp-6. After the switch control signal Sc-6 is input to the heating control substrate 22, it is transmitted in the wiring psc6 and the wiring ps6, and is input to the control terminal of the switch SW-6. Thus, the conduction state of the switch SW-6 is controlled, and the current amount of the heating current Ihc-6 supplied to the ink heating unit 700-6 is controlled. As a result, the temperature of the heating unit 710 of the ink heating unit 700-6 that generates heat according to the current amount of the heating current Ihc-6 is controlled.

[0185] Similarly, the connector 29 to which the voltage signal VHC outputted from the power supply circuit 101 is inputted and the cable 730-7 connected to the ink heating unit 700-7 mounted on the ink sub-tank 750-4 are electrically connected via the wiring pih1 and the wiring pih6, the wiring pih5 and the wiring pih10, the switch SW-7, and the wiring pc7. Therefore, the heating current Ihc-7 is transmitted through the wiring pih1 and the wiring pih6, and the wiring pih5 and the wiring pih10, and is supplied to the heating unit 710 of the ink heating unit 700-7 via the switch SW-7, the wiring pc7, and the cable 730-7. In addition, the temperature detection unit 720 of the ink heating unit 700-7 outputs a temperature detection signal Tmp-7 based on the temperature of the heating unit 710. After the temperature detection signal Tmp-7 is input to the heating control substrate 22 via the cable 730-7, it is transmitted through the wiring pt7 and the wiring ptm7, and is input to the temperature control circuit 500 via the wiring TM. The temperature control circuit 500 outputs a switch control signal Sc-7 corresponding to the input temperature detection signal Tmp-7. After the switch control signal Sc-7 is input to the heating control substrate 22, it is transmitted through the wiring psc7 and the wiring ps7, and is input to the control terminal of the switch SW-7. Thus, the conduction state of the switch SW-7 is controlled, and the current amount of the heating current Ihc-7 supplied to the ink heating unit 700-7 is controlled. As a result, the temperature of the heating unit 710 of the ink heating unit 700-7 that generates heat according to the current amount of the heating current Ihc-7 is controlled.

[0186] Similarly, the connector 29 to which the voltage signal VHC outputted from the power supply circuit 101 is inputted and the cable 730-8 connected to the ink heating unit 700-8 mounted on the ink sub-tank 750-4 are electrically connected via the wiring pih1 and the wiring pih6, the wiring pih5 and the wiring pih10, the switch SW-8, and the wiring pc8. Therefore, the heating current Ihc-8 is transmitted through the wiring pih1 and the wiring pih6, and the wiring pih5 and the wiring pih10, and is supplied to the heating unit 710 of the ink heating unit 700-8 via the switch SW-8, the wiring pc8, and the cable 730-8. In addition, the temperature detection unit 720 of the ink heating unit 700-8 outputs a temperature detection signal Tmp-8 based on the temperature of the heating unit 710. After the temperature detection signal Tmp-8 is input to the heating control substrate 22 via the cable 730-8, it is transmitted in the wiring pt8 and the wiring ptm8, and is input to the temperature control circuit 500 via the wiring TM. The temperature control circuit 500 outputs a switch control signal Sc-8 corresponding to the input temperature detection signal Tmp-8. After the switch control signal Sc-8 is input to the heating control substrate 22, it is transmitted in the wiring psc8 and the wiring ps8, and is input to the control terminal of the switch SW-8. Thus, the conduction state of the switch SW-8 is controlled, and the current amount of the heating current Ihc-8 supplied to the ink heating unit 700-8 is controlled. As a result, the temperature of the heating unit 710 of the ink heating unit 700-8 that generates heat according to the current amount of the heating current Ihc-8 is controlled.

[0187] Here, as described above, the heating section 710 of each of the ink heating sections 700-1 to 700-8 generates heat according to the amount of current supplied by the heating currents Ihc-1 to Ihc-8. Therefore, there is a case where a current of several amperes is supplied to each of the heating sections 710 of the ink heating sections 700-1 to 700-8 according to the temperature. Therefore, there is a case where a large current of several amperes flows in the wirings pih2 to pih5 and the wirings pih7 to pih10 of the heating control substrate 22 through which the heating currents Ihc-1 to Ihc-8 flow, and further, there is a case where a current of several amperes to several tens of amperes flows in the wirings pih1 and the wirings pih6 through which the heating currents Ihc-1 to Ihc8 are added together.

[0188] The heating control substrate 22 in which such a large current flows generates heat through the current values ​​of the heating currents Ihc, Ihc-1 to Ihc-8 and the impedance of the wirings pih1 to pih10 through which the heating currents Ihc, Ihc-1 to Ihc-8 flow. In particular, in the liquid ejection device 1 of the present embodiment, since the current amounts of the heating currents Ihc, Ihc-1 to Ihc-8 are large currents of several amperes to tens of amperes, the heating control substrate 22 will become high temperature. Therefore, there is a situation in which, even after the supply of the heating currents Ihc-1 to Ihc-8 is stopped, the temperature of the heating control substrate 22 will continue to be in a high temperature state for a fixed period of time. That is, there is a situation in which the heating control substrate 22 will maintain a high temperature state even when the power supply to the liquid ejection device 1 is stopped.

[0189] Therefore, when the inspection process implemented when manufacturing the liquid ejection device 1 or the maintenance of the liquid ejection device 1 is performed, the worker may contact the heating control substrate 22, and the operation may be interrupted and waited for a fixed period of time during which the heat generated in the heating control substrate 22 is fully released. However, when this operation is performed, since the fixed period of waiting is performed instead of the actual temperature of the heating control substrate 22, the waiting may be performed even though the temperature of the heating control substrate 22 has been sufficiently lowered, and as a result, there is a possibility that the operation efficiency may be reduced, and there is also a possibility that the operation may be started even though the temperature of the heating control substrate 22 has not been sufficiently lowered.

[0190] That is, in the liquid ejection device 1 having the heating unit 710 as shown in the present embodiment, since the temperature of the ink ejected from the liquid ejection head 400 can be controlled by the heating unit 710, the ink ejection accuracy can be improved. On the other hand, in the inspection process or maintenance of the liquid ejection device 1, a new problem is generated, that is, the operator may not be able to grasp the heating state of the heating control substrate 22, thereby reducing the workability and the convenience of the liquid ejection device 1. In view of the problem involved, the liquid ejection device 1 of the present embodiment has a notification function for notifying the operator whether the temperature of the heating control substrate 22 is high.

[0191] An example of a specific structure of the heating control substrate 22 having such a notification function will be described. Fig.17 2 is a diagram showing an example of the structure of the surface 211 of the heating control substrate 22. Fig.17As shown, on the surface 211 of the heating control substrate 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, temperature sensing units 260-1 to 260-5 for sensing the temperature of the heating control substrate 22 are also provided. That is, the liquid ejection device 1 includes temperature sensing units 260-1 to 260-5 provided on the surface 211 of the heating control substrate 22. Here, the temperature sensing units 260-1 to 260-5 all have the same structure, and when there is no need to distinguish them, they are sometimes simply referred to as the temperature sensing unit 260. In addition, Fig.17 In FIG. 2 , a wiring pattern provided on a layer 231 located adjacent to the surface 211 is illustrated by a dotted line.

[0192] The temperature notification unit 260 can use, for example, a reversible temperature indicating paint. The reversible temperature indicating paint refers to a paint that includes a colorless dye as an electron donating compound, a developer as an electron acceptor compound, and a decolorizing material for controlling a color change temperature range, and changes the color of the temperature indicating paint from the color of the initial state by changing from an initial state where the temperature of the temperature indicating paint is less than a predetermined threshold temperature to a temperature indicating state where the temperature of the temperature indicating paint is greater than a predetermined threshold temperature, and returns the color of the temperature indicating paint to the color of the initial state by changing from a temperature indicating state where the temperature of the temperature indicating paint is greater than a predetermined threshold temperature to an initial state where the temperature of the temperature indicating paint is less than a predetermined threshold temperature. Here, the color of the initial state of the temperature indicating paint includes, for example, light pink, light green, white, etc., and the color tone of the temperature indicating paint in the temperature indicating state includes purple, cyan, black, etc. In addition, the color tone of the temperature indicating paint in the initial state and the color tone in the temperature indicating state are not limited thereto, and various colors can be used according to the characteristics of the colorless dye.

[0193] That is, the temperature notification unit 260 includes an initial state indicating that the temperature of the temperature notification unit 260 is less than a predetermined threshold temperature, and a temperature display state indicating that the temperature of the temperature notification unit 260 is greater than a predetermined threshold temperature, and the color is different in the initial state and the temperature display state. Further, the initial state and the temperature display state of the temperature notification unit 260 change reversibly according to whether the temperature of the temperature notification unit 260 is less than a predetermined threshold temperature or the temperature of the temperature notification unit 260 is greater than a predetermined threshold temperature. In other words, the temperature notification unit 260 shows that the temperature of the temperature notification unit 260 is less than the threshold temperature in the initial state, and shows that the temperature of the temperature notification unit 260 is greater than the threshold temperature in the temperature display state, and the initial state and the temperature display state change reversibly.

[0194] This allows the operator to visually detect the temperature of the heating control substrate 22. As a result, the operator can easily understand the heating state of the heating control substrate 22, which reduces the possibility of significantly reducing workability and the convenience of the liquid ejection device 1.

[0195] Furthermore, by using a temperature indicating paint as the temperature notifying portion 260, whether the temperature notifying portion 260 is in the initial state or the temperature indicating state changes according to the temperature of the temperature notifying portion 260. In other words, the initial state and the temperature indicating state change in a reversible manner, independent of the presence or absence of power supply to the liquid ejecting device 1 including the power supply circuit 101. As a result, even when power is not supplied to the liquid ejecting device 1, the staff can easily grasp the heating state of the heating control substrate 22, thereby reducing the possibility of a significant reduction in workability and reducing the possibility of a reduction in the convenience of the liquid ejecting device 1.

[0196] Furthermore, it is preferred that the area where the temperature notification part 260 is provided in the heating control substrate 22 is an area where white screen printing is implemented. Thus, the staff can more clearly grasp the color change of the temperature indicating paint used as the temperature notification part 260, and as a result, the temperature notification part 260 can more clearly notify the heating state of the heating control substrate 22 to the staff.

[0197] In addition, the temperature notification unit 260 only needs to be able to change the temperature notification unit 260 in a reversible manner to indicate whether it is the initial state or the temperature indicating state according to the temperature of the temperature notification unit 260. Therefore, in the temperature notification unit 260, instead of the temperature indicating paint, or on the basis of the temperature indicating paint, a thermoelectric conversion element and a light emitting element that emits light according to the output of the thermoelectric conversion element may be included.

[0198] In this case, the thermoelectric conversion element included in the temperature notification unit 260 outputs power corresponding to the temperature detected by the thermoelectric conversion element, and the light-emitting element included in the temperature notification unit 260 emits light by the power corresponding 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 less than the predetermined threshold temperature is different from the output power output by the thermoelectric conversion element when the temperature of the thermoelectric conversion element is greater 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 is also different when the temperature of the thermoelectric conversion element is less than the predetermined threshold temperature and when the temperature of the thermoelectric conversion element is greater than the predetermined threshold temperature.

[0199] That is, even when the temperature notification unit 260 is configured to include a thermoelectric conversion element and a light emitting element that emits light according to the output of the thermoelectric conversion element, the temperature state of the heating control substrate 22 can be visually notified to the operator based on the difference in the light emitting state of the light emitting element in the initial state and the temperature indicating state of the temperature notification unit 260. As a result, the operator can easily grasp the heating state of the heating control substrate 22, thereby reducing the possibility of significantly reducing the workability and reducing the convenience of the liquid ejection device 1.

[0200] In addition, the predetermined threshold temperature described above, in which the state of the temperature indicating paint used as the temperature notifying 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. In other words, as the temperature indicating paint used as the temperature notifying units 260-1 to 260-5, it is preferable to use a temperature indicating paint that changes between the initial state and the temperature indicating state in the range of 40 to 70 degrees.

[0201] In the case of the liquid ejection device 1 that ejects ink by driving the piezoelectric element 60 as shown in the present embodiment, there is a case where the temperature of the liquid ejection head 400 becomes high temperature and the stability of the operation of the liquid ejection head 400 decreases. Therefore, when the temperature of the ink supplied to the liquid ejection head 400 becomes high temperature, the possibility of the stability of the operation of the liquid ejection head 400 decreasing increases. As a temperature indicating paint used as the temperature notification unit 260-1 to 260-5, by using a temperature indicating paint that changes between an initial state and a temperature indicating state within a range of 40 degrees to 70 degrees, the state of the temperature of the ink supplied to the liquid ejection head 400 can be visually recognized. That is, the temperature notification units 260-1 to 260-5 can notify the state of the ink supplied to the liquid ejection head 400.

[0202] Here, the temperature indicating paint used by each of the temperature indicating parts 260-1 to 260-5 may be of different properties, and the colors of each of the temperature indicating parts 260-1 to 260-5 in the initial state may be different. Similarly, the colors of each of the temperature indicating parts 260-1 to 260-5 in the temperature indicating state may be different.

[0203] Next, an example of the arrangement of the temperature reporting unit 260 in the heating control substrate 22 will be described.

[0204] The temperature notification unit 260-1 is located at a position where at least a portion overlaps with the wiring pih1 when the heating control substrate 22 is viewed from above and when viewed from the -z side along the z direction which is the normal direction of the heating control substrate 22. In this case, the temperature notification unit 260-1 is located at a position closer to the +x side than the connection point to which one end of the wiring pih5 is connected in the wiring pih1 extending along the x direction. In other words, the temperature notification unit 260-1 is located at a position closer to the connector 29 than any of the wirings pih2 to pih5 in the wiring pih1 extending along the x direction. Thus, the temperature notification unit 260-1 detects the temperature of the wiring pih1.

[0205] The temperature notification unit 260-2 is located at a position where at least a portion overlaps with the wiring pih2 when the heating control substrate 22 is viewed from above and when it is viewed from the -z side along the z direction which is the normal direction of the heating control substrate 22. Thus, the temperature notification unit 260-2 detects the temperature of the wiring pih2. In addition, the temperature notification unit 260-3 is located at a position where at least a portion overlaps with the wiring pih3 when the heating control substrate 22 is viewed from above and when it is viewed from the -z side along the z direction which is the normal direction of the heating control substrate 22. Thus, the temperature notification unit 260-3 detects the temperature of the wiring pih3. In addition, the temperature notification unit 260-4 is located at a position where at least a portion overlaps with the wiring pih4 when the heating control substrate 22 is viewed from above and when it is viewed from the -z side along the z direction which is the normal direction of the heating control substrate 22. Thus, the temperature notification unit 260-4 detects the temperature of the wiring pih4. The temperature reporting unit 260-5 is located at a position where at least a portion overlaps with the wiring pih5 when the heating control substrate 22 is viewed from above and viewed from the -z side along the z direction which is the normal direction of the heating control substrate 22. Thus, the temperature reporting unit 260-5 detects the temperature of the wiring pih5.

[0206] That is, at least a portion of the temperature sensing portion 260-1 is located at a position overlapping at least a portion of the wiring pih1 on a layer 231 located closest to the surface 211 among the plurality of wiring layers of the heating control substrate 22 in the normal direction of the heating control substrate 22, at least a portion of the temperature sensing portion 260-2 is located at a position overlapping at least a portion of the wiring pih2 on a layer 231 located closest to the surface 211 among the plurality of wiring layers of the heating control substrate 22 in the normal direction of the heating control substrate 22, and at least a portion of the temperature sensing portion 260-3 is located at a position overlapping at least a portion of the wiring pih2 on a layer 231 located closest to the surface 211 among the plurality of wiring layers of the heating control substrate 22 in the normal direction of the heating control substrate 22. At a position where at least a portion of the wiring pih3 on the layer 231 located closest to the surface 211 among the multiple wiring layers possessed by the heating control substrate 22 overlaps, at least a portion of the temperature sensing portion 260-4 is located at a position where it overlaps with at least a portion of the wiring pih4 on the layer 231 located closest to the surface 211 among the multiple wiring layers possessed by the heating control substrate 22 in the normal direction of the heating control substrate 22, and at least a portion of the temperature sensing portion 260-5 is located at a position where it overlaps with at least a portion of the wiring pih5 on the layer 231 located closest to the surface 211 among the multiple wiring layers possessed by the heating control substrate 22 in the normal direction of the heating control substrate 22.

[0207] In other words, different wiring patterns are not located between the temperature reporting units 260-1 to 260-5 and the wirings pih1 to pih5 for measuring the temperature of the temperature reporting units 260-1 to 260-5. Thus, in the heating control substrate 22, the detection accuracy of the temperature of the wirings pih1 to pih5 which may become high in particular is improved.

[0208] Furthermore, if Fig.17 As shown in FIG. 1 , preferably, in the heating control substrate 22, the temperature reporting portions 260-2 to 260-5 are located in a row in the x direction intersecting the z direction which is the normal direction of the heating control substrate 22. Thus, the visual confirmation of the temperature reporting portions 260-2 to 260-5 based on the temperature of the heating control substrate 22 is improved.

[0209] 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 or the heating unit 710 included in the ink heating unit 700-2 that contacts at least a portion of the ink sub-tank 750-1 is an example of a first heating element, at least one of the heating current Ihc-1 for heating the heating unit 710 included in the ink heating unit 700-1 and the heating current Ihc-2 for heating the heating unit 710 included in the ink heating unit 700-2 is an example of a first driving current, the wiring pih2 for transmitting the heating current Ihc-1 and the heating current Ihc-2 is an example of a first transmission wiring, and the temperature notification unit 260-2 arranged to overlap with the wiring pih2 is an example of a first temperature indicating unit. Moreover, the initial state of the temperature notification unit 260-2 is an example of the first state, the temperature indication state of the temperature notification unit 260-2 is an example of the second state, and the threshold temperature at which the initial state and the temperature indication state of the temperature notification unit 260-2 change is an example of the first threshold.

[0210] In addition, 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 or the heating unit 710 included in the ink heating unit 700-4 that contacts at least a portion of the ink sub-tank 750-2 is an example of a second heating element, at least one of the heating current Ihc-3 for heating the heating unit 710 included in the ink heating unit 700-3 and the heating current Ihc-4 for heating the heating unit 710 included in the ink heating unit 700-4 is an example of a second driving current, the wiring pih3 for transmitting the heating current Ihc-3 and the heating current Ihc-4 is an example of a second transmission wiring, and the temperature notification unit 260-3 arranged in a manner overlapping with the wiring pih3 is an example of a second temperature indicating unit. Moreover, the initial state of the temperature alarm unit 260-3 is an example of the third state, the temperature indication state of the temperature alarm unit 260-3 is an example of the fourth state, and the threshold temperature at which the initial state and the temperature indication state of the temperature alarm unit 260-3 change is an example of the second threshold.

[0211] In addition, the temperature sensing units 260-2 to 260-5 provided on the heating control substrate 22 are an example of a plurality of temperature sensing units, the heating control substrate 22 is an example of a wiring substrate, the power supply circuit 101 that outputs the heating currents Ihc, Ihc-1 to Ihc-8 transmitted in the heating control substrate 22 is an example of a driving current output circuit, the surface 211 of the heating control substrate 22 is an example of a first surface, the surface 212 is an example of a second surface, and the layer 231 located closest to the surface 211 among the plurality of wiring layers of the heating control substrate 22 is an example of a transmission wiring layer.

[0212] 4. Effects

[0213] As described above, the liquid ejection device 1 of the present embodiment comprises: a liquid ejection head 400-1 for ejecting ink; an ink sub-tank 750-1 for supplying ink to the liquid ejection head 400-1; a heating section 710 included in the ink heating section 700-1 at least partially in contact with the ink sub-tank 750-1, and a heating section 710 included in the ink heating section 700-2; a heating control substrate 22 including a surface 211, a surface 212 different from the surface 211, and a wiring pih2 for transmitting at least one of a heating current Ihc-1 supplied to the heating section 710 included in the ink heating section 700-1 and a heating current Ihc-2 supplied to the heating section 710 included in the ink heating section 700-2; and a temperature reporting section 260-2 arranged on the surface 211.

[0214] Moreover, in the liquid ejection device 1 of the present embodiment, the temperature notification unit 260-2 indicates the case where the temperature of the temperature notification unit 260-2 is less than the threshold temperature in the initial state, and indicates the case where the temperature of the temperature notification unit 260-2 is above the threshold temperature in the temperature indication state, and the initial state and the temperature indication state change in a reversible manner. Thus, the temperature notification unit 260-2 can notify whether the detected temperature is a low temperature less than the threshold temperature or a high temperature above the threshold temperature. Further, the temperature notification unit 260-2 is located at a position where at least a portion overlaps with at least a portion of the wiring pih2 in the normal direction of the heating control substrate 22. Thus, the temperature notification unit 260-2 can effectively detect the temperature of the wiring pih2 that may become a high temperature in the heating control substrate 22.

[0215] That is, in the liquid ejection device 1 of the present embodiment, the temperature notification unit 260-2 can effectively detect the heat generated by the heating control substrate 22 due to the transmission path with a large current flowing, and can notify the detection result to the staff. As a result, the staff can easily grasp the heating state of the heating control substrate 22. As a result, even if the liquid ejection device 1 has a large current flowing due to the heating unit 710 that heats the ink, the possibility of reduced workability in the inspection process at the manufacturing stage or the maintenance of the liquid ejection device 1 can be reduced, and the possibility of reduced convenience of the liquid ejection device 1 is also reduced.

[0216] Furthermore, the liquid ejection device 1 of the present embodiment comprises: a liquid ejection head 400-2 for ejecting ink; an ink sub-tank 750-2 for supplying ink to the liquid ejection head 400-2; a heating section 710 included in an ink heating section 700-3 at least a portion of which is in contact with the ink sub-tank 750-2, and a heating section 710 included in an ink heating section 700-4; a temperature sensing section 260-3 arranged on a surface 211, and a heating control substrate 22 including a wiring pih3 for transmitting at least one of a heating current Ihc-3 supplied to the heating section 710 included in the ink heating section 700-3 and a heating current Ihc-4 supplied to the heating section 710 included in the ink heating section 700-4.

[0217] Moreover, in the liquid ejection device 1 of the present embodiment, the temperature notification unit 260-3 indicates the case where the temperature of the temperature notification unit 260-3 is less than the threshold temperature in the initial state, and indicates the case where the temperature of the temperature notification unit 260-3 is above the threshold temperature in the temperature indication state, and the initial state and the temperature indication state change in a reversible manner, and at least a part is located at a position overlapping with at least a part of the wiring pih3 in the normal direction of the heating control substrate 22. Thus, in the liquid ejection device 1, even in the case where there are multiple transmission paths with large current flowing, the heating of the heating control substrate 22 can be effectively detected, and the detection result can be notified to the staff. Therefore, the staff can easily grasp the heating state of the heating control substrate 22, and as a result, even if the liquid ejection device 1 has a large current flowing due to the heating unit 710 that heats the ink, the possibility of reduced operability in the inspection process at the manufacturing stage or the maintenance of the liquid ejection device 1 is further reduced, and the possibility of reduced convenience of the liquid ejection device 1 is further reduced.

[0218] As described above, in the liquid ejection device 1 of the present embodiment, the worker can easily grasp the heating state of the heating control substrate 22. Therefore, even when the liquid ejection device 1 is a printing and dyeing printer using high-viscosity ink and has a heating unit 710 for heating the ink and thus a large current flows, the possibility of reduced operability in the inspection process at the manufacturing stage or maintenance of the liquid ejection device 1 can be further reduced, and the possibility of reduced convenience of the liquid ejection device 1 can also be further reduced.

[0219] 5. Change example

[0220] In the above-mentioned liquid ejection device 1 of the present embodiment, the temperature sensing parts 260-1 to 260-5 arranged on the heating control substrate 22 are explained as changing between an initial state and a temperature indication state according to the temperature of the temperature sensing part 260, but the temperature sensing parts 260-1 to 260-5 may also each include an initial state indicating a case where the temperature of the temperature sensing part 260 is lower than a predetermined threshold temperature, a first temperature indication state in a temperature indication state indicating a case where the temperature of the temperature sensing part 260 is higher than a predetermined threshold temperature, and a second temperature indication state in a temperature indication state indicating a case where the temperature of the temperature sensing part 260 is higher than a high temperature threshold temperature compared to the predetermined threshold temperature, and different colors are used in the initial state, the first temperature indication state, and the second temperature indication state.

[0221] Thus, the worker can be visually informed of the details of the temperature state of the heating control substrate 22. As a result, the worker can more clearly and easily grasp the heating state of the heating control substrate 22, further reducing the possibility of a significant reduction in workability and the possibility of a reduction in the convenience of the liquid ejection device 1.

[0222] Here, the second temperature indicating state of the temperature notifying unit 260 - 1 is an example of the fifth state, and the high temperature threshold temperature at which the first temperature indicating state and the second temperature indicating state of the temperature notifying unit 260 - 1 change is an example of the third threshold.

[0223] Although the embodiments and the modified examples have been described above, the present invention is not limited to these embodiments, and can be implemented in various forms within the scope of the gist thereof. For example, the above-described embodiments can be appropriately combined.

[0224] The present invention includes structures that are substantially the same as the structures described in the embodiments (for example, structures with the same functions, methods and results, or structures with the same purposes and effects). In addition, the present invention includes structures obtained by replacing non-essential parts of the structures described in the embodiments. In addition, the present invention includes structures that have the same effects as the structures described in the embodiments or structures that can achieve the same purposes. In addition, the present invention includes structures to which known technologies are added to the structures described in the embodiments.

[0225] The following contents can be derived from the above-mentioned embodiments and modifications.

[0226] One embodiment of a liquid ejecting device is a liquid ejecting device that forms an image on a medium by ejecting liquid, and includes:

[0227] a first spray head that sprays liquid;

[0228] a first liquid supplying unit for supplying liquid to the first ejection head;

[0229] a first heating element, at least a portion of which is in contact with the first liquid supply portion;

[0230] a wiring substrate including a first surface, a second surface different from the first surface, and a first transmission wiring that transmits a first drive current supplied to the first heating element;

[0231] a first temperature indicating portion, which is disposed on the first surface;

[0232] The first temperature indicating portion indicates that the temperature of the first temperature indicating portion is less than a first threshold value in a first state, and indicates that the temperature of the first temperature indicating portion is greater than the first threshold value in a second state, and the first state and the second state change in a reversible manner.

[0233] At least a portion of the first temperature indicating portion overlaps with at least a portion of the first transfer wiring in a normal direction of the wiring substrate.

[0234] According to the liquid ejection device, there is a first temperature indicating portion which indicates a temperature less than a first threshold value in a first state and indicates a temperature greater than the first threshold value in a second state, and the first state and the second state change in a reversible manner, and by at least a portion of the first temperature indicating portion being located at a position overlapping with at least a portion of the first transmission wiring in a normal direction of the wiring substrate, the first temperature indicating portion can effectively detect whether the wiring substrate is at a high temperature and notify the staff.

[0235] In one embodiment of the liquid ejection device, the following embodiment may be adopted:

[0236] That is, the first temperature indicating portion has different colors in the first state and the second state.

[0237] According to this liquid discharge device, since the color of the first temperature indicating portion is different between the first state and the second state, it is possible to visually inform a worker whether the wiring board is at a high temperature.

[0238] In one embodiment of the liquid ejection device, the following embodiment may be adopted:

[0239] That is, a carriage is provided, and the carriage reciprocates along a main scanning direction intersecting with a conveying direction in which the medium is conveyed.

[0240] The wiring substrate is mounted on the carriage.

[0241] In one embodiment of the liquid ejection device, the following embodiment may be adopted:

[0242] That is, a driving current output circuit is provided, and the driving current output circuit outputs the first driving current,

[0243] The first state and the second state change reversibly regardless of whether or not the power supply to the drive current output circuit is supplied.

[0244] According to this liquid ejection device, the first temperature indicating unit can effectively detect whether or not the wiring board has reached a high temperature due to residual heat after the power supply to the liquid ejection device is stopped.

[0245] In one embodiment of the liquid ejection device, the following embodiment may be adopted:

[0246] That is, the wiring substrate has a plurality of wiring layers located between the first surface and the second surface.

[0247] The plurality of wiring layers include a transmission wiring layer provided with at least a portion of the first transmission wiring,

[0248] The transmission wiring layer is located at a position closest to the first surface among the plurality of wiring layers.

[0249] According to this liquid discharge device, the efficiency of detecting whether or not the wiring substrate is at a high temperature by the first temperature indicating unit is improved.

[0250] In one embodiment of the liquid ejection device, the following embodiment may be adopted:

[0251] That is, at least a portion of the first temperature indicating portion overlaps with at least a portion of the first transfer wiring provided on the transfer wiring layer in the normal direction.

[0252] According to this liquid discharge device, the efficiency of detecting whether or not the wiring substrate is at a high temperature by the first temperature indicating unit is improved.

[0253] In one embodiment of the liquid ejection device, the liquid ejection device may include:

[0254] a second spray head that sprays liquid;

[0255] a second liquid supplying unit, which supplies liquid to the second ejection head;

[0256] a second heating element, at least a portion of which is in contact with the second liquid supply portion;

[0257] a second temperature indicating portion, which is disposed on the first surface;

[0258] The wiring substrate includes a second transmission wiring that transmits a second drive current supplied to the second heating element.

[0259] The second temperature indicating portion indicates that the temperature of the second temperature indicating portion is less than a second threshold value in a third state, and indicates that the temperature of the second temperature indicating portion is greater than the second threshold value in a fourth state, and the third state and the fourth state change in a reversible manner.

[0260] At least a portion of the second temperature indicating portion overlaps with at least a portion of the second transfer wiring in the normal direction.

[0261] According to the liquid ejection device, there is a second temperature indicating portion which indicates that the temperature is less than a second threshold value in the third state and that the temperature is above the second threshold value in the fourth state, and the third state and the fourth state change in a reversible manner, and by at least a portion of the second temperature indicating portion being located at a position overlapping with at least a portion of the second transmission wiring in the normal direction of the wiring substrate, it is possible to effectively detect whether the wiring substrate is at a high temperature over a larger range.

[0262] In one embodiment of the liquid ejection device, the following embodiment may be adopted:

[0263] That is, the wiring substrate has a plurality of temperature indicating portions including the first temperature indicating portion and the second temperature indicating portion.

[0264] The plurality of temperature indicating portions are located at positions arranged in a row in a direction intersecting the normal direction.

[0265] According to this liquid discharge device, it is possible to effectively notify a worker of the detection result of whether or not the wiring board is at a high temperature.

[0266] In one embodiment of the liquid ejection device, the following embodiment may be adopted:

[0267] That is, the first temperature indicating unit indicates that the temperature of the first transmission line is greater than or equal to the first threshold value and greater than or equal to the third threshold value in the fifth state.

[0268] The first temperature indicating portion has different colors in the first state, the second state, and the fifth state.

[0269] According to this liquid discharge device, by making the color of the first temperature indicating portion different in the first state, the second state, and the third state, it is possible to visually inform a worker whether the wiring board is at a high temperature in multiple stages.

[0270] In one embodiment of the liquid ejection device, the following embodiment may be adopted:

[0271] That is, the liquid ejecting device is a printing and dyeing printer.

[0272] In one embodiment of the liquid ejection device, the following embodiment may be adopted:

[0273] That is, the first threshold is in the range of 40 degrees to 70 degrees.

[0274] In one embodiment of the liquid ejection device, the following embodiment may be adopted:

[0275] That is, the first temperature indicating portion includes a temperature indicating paint.

[0276] In one embodiment of the liquid ejection device, the following embodiment may be adopted:

[0277] That is, the first temperature indicating portion includes a thermoelectric conversion element and a light emitting element.

[0278] Explanation of symbols

[0279] 1…Liquid ejection device; 2…Control unit; 3…Unwinding unit; 4…Supporting unit; 5…Conveying unit; 6…Printing unit; 10…Control unit; 20…Head unit; 21…Ejection control substrate; 22…Heating control substrate; 24, 28, 29…Connector; 30…Drive circuit substrate; 31…Holding member; 32…Roller body; 41…First supporting unit; 42…Second supporting unit; 43…Third supporting unit; 51…Conveying motor; 52…Conveying roller; 53…Driven roller; 60…Piezoelectric element; 61… Moving mechanism; 62...guide member; 63...guide rail; 64...slide support; 71...slide; 72...slide body; 73...slide cover; 74...connecting substrate; 75-77...connector; 81...housing; 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 alarm ; 300…driving circuit; 310…driving signal output circuit; 320…reference voltage signal output circuit; 400…liquid ejection head; 420…driving signal selection circuit; 430…selection control circuit; 432…shift register; 434…latch circuit; 436…decoder; 440…selection circuit; 442a, 442b…inverter; 444a, 444b…transmission gate; 500…temperature control circuit; 600…ejection unit; 601…piezoelectric body; 611, 612…electrode ; 621…vibration plate; 631…cavity; 632…nozzle plate; 641…liquid reservoir; 651…nozzle; 661…supply port; 700…ink heating unit; 710…heating unit; 720…temperature detection unit; 730…cable; 750…ink sub-tank; P…medium; SW…switch; TM, pc1~pc8, pcs1~pcs8, pih1~pih10, ps1~ps8, psc1~psc8, pt1~pt8, ptm1~ptm8…wiring.

Claims

1. A liquid ejection device, characterized in that: The liquid ejection device forms an image on a medium by ejecting liquid. The liquid ejection device comprises: a first spray head that sprays liquid; a first liquid supplying unit for supplying 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 transmission wiring that transmits a first drive current supplied to the first heat generating element; a first temperature indicating portion, which is disposed on the first surface; The first temperature indicating portion indicates that the temperature of the first temperature indicating portion is less than a first threshold value in a first state, and indicates that the temperature of the first temperature indicating portion is greater than the first threshold value in a second state, and the first state and the second state change in a reversible manner. At least a portion of the first temperature indicating portion overlaps with at least a portion of the first transfer wiring in a normal direction of the wiring substrate.

2. The liquid ejection device according to claim 1, wherein: The first temperature indicating portion has different colors in the first state and the second state.

3. The liquid ejection device according to claim 1 or 2, characterized in that: A carriage is provided, the carriage reciprocating along a main scanning direction intersecting with a conveying direction in which the medium is conveyed, The wiring substrate is mounted on the slider.

4. The liquid ejection device according to claim 1, wherein: A driving current output circuit is provided, wherein the driving current output circuit outputs the first driving current, The first state and the second state change reversibly regardless of whether or not the power supply to the drive current output circuit is supplied.

5. The liquid ejection device according to claim 1, wherein: The wiring substrate includes a plurality of wiring layers located between the first surface and the second surface. The plurality of wiring layers include a transmission wiring layer provided with at least a portion of the first transmission wiring, The transmission wiring layer is located at a position closest to the first surface among the plurality of wiring layers.

6. The liquid ejection device according to claim 5, characterized in that: At least a portion of the first temperature indicating portion overlaps with at least a portion of the first transfer wiring provided on the transfer wiring layer in the normal direction.

7. The liquid ejection device according to claim 1, wherein: have: a second spray head that sprays liquid; a second liquid supplying unit for supplying 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, which is disposed on the first surface; The wiring substrate includes a second transmission wiring that transmits a second drive current supplied to the second heating element. The second temperature indicating portion indicates that the temperature of the second temperature indicating portion is less than a second threshold value in a third state, and indicates that the temperature of the second temperature indicating portion is greater than the second threshold value in a fourth state, and the third state and the fourth state change in a reversible manner. At least a portion of the second temperature indicating portion overlaps with at least a portion of the second transfer wiring in the normal direction.

8. The liquid ejection device according to claim 7, characterized in that: The wiring substrate includes 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 located at positions arranged in a row in a direction intersecting the normal direction.

9. The liquid ejection device according to claim 1, wherein: In a fifth state, the first temperature indicating unit indicates that the temperature of the first transmission line is greater than or equal to the first threshold value and greater than or equal to a third threshold value. The first temperature indicating portion has different colors in the first state, the second state, and the fifth state.

10. The liquid ejection device according to claim 1, wherein: The liquid ejecting device is a printing and dyeing printer.

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

12. The liquid ejection device according to claim 1, wherein: The first temperature indicating portion includes a temperature indicating paint.

13. The liquid ejection device according to claim 1, wherein: The first temperature indicating portion includes a thermoelectric conversion element and a light emitting element.

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