Liquid ejecting apparatus and driving apparatus

Abstract

The invention provides a liquid ejecting apparatus and a driving apparatus. The purpose of the present invention is to suppress temperature increase in an analog conversion circuit that specifies the waveform of a drive signal. The liquid ejecting apparatus includes: a liquid ejecting head that is driven by a drive signal to eject a liquid; a first substrate; a transistor pair provided on the first substrate and including two bipolar transistors that generate driving signals; a second substrate; and an analog conversion circuit provided on the second substrate and converting a digital first waveform signal specifying the waveform of the drive signal into an analog second waveform signal specifying the waveform of the drive signal, the transistor pair generating the drive signal based on the second waveform signal, and the second substrate being provided separately from the first substrate.

Description

Technical Field

[0001] This invention relates to a liquid ejection device and a driving device. Background Technology

[0002] Liquid ejection devices are known to include a liquid ejection head and a drive signal generation circuit. The liquid ejection head ejects liquids such as ink according to a drive signal, and the drive signal generation circuit supplies the drive signal to the liquid ejection head. For example, Patent Document 1 discloses a liquid ejection device equipped with a drive signal generation circuit, which includes: an analog-to-digital converter circuit that specifies the waveform of the drive signal; and a pair of transistors that generate the drive signal based on the output from the analog-to-digital converter circuit.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-099852

[0004] The drive signal for the liquid nozzle is a large-amplitude signal, and the transistor pairs generate heat when generating the drive signal. Furthermore, during the drive signal generation circuit, the heat generated by the transistor pairs is transferred to the analog-to-digital converter circuit, causing the converter circuit to become overheated. Therefore, there is a possibility that the operation of the analog-to-digital converter circuit may become unstable during the drive signal generation process. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the liquid ejection device of the present invention is characterized by comprising: a liquid ejection head that is driven by a drive signal to eject liquid; a first substrate; a transistor pair disposed on the first substrate and including two bipolar transistors for generating the drive signal; a second substrate; and an analog-to-digital conversion circuit disposed on the second substrate that converts a first waveform signal that modifies the waveform of the drive signal with a specified digital signal into a second waveform signal that modifies the waveform of the drive signal with a specified analog signal, wherein the transistor pair generates the drive signal based on the second waveform signal, and the second substrate is configured to be separate from the first substrate.

[0006] Furthermore, the driving device of the present invention is characterized in that the driving device supplies a driving signal to a liquid nozzle, the liquid nozzle being driven by the driving signal to eject liquid, the driving device comprising: a first substrate; a transistor pair disposed on the first substrate and including two bipolar transistors for generating the driving signal; a second substrate; and an analog-to-digital conversion circuit disposed on the second substrate, converting a digital first waveform signal specifying the waveform of the driving signal into an analog second waveform signal specifying the waveform of the driving signal, the transistor pair generating the driving signal based on the second waveform signal, and the second substrate being configured to be separate from the first substrate. Attached Figure Description

[0007] Figure 1 This is a block diagram illustrating an example of the structure of an inkjet printer 1 according to an embodiment of the present invention.

[0008] Figure 2 This is a perspective view showing an example of the simplified internal structure of an inkjet printer 1.

[0009] Figure 3 This is a cross-sectional view showing an example of the structure of the ejector section D[m].

[0010] Figure 4 This is a block diagram showing an example of the structure of the liquid ejection unit 3.

[0011] Figure 5 This is a timing diagram showing an example of the signal supplied to the liquid ejection unit 3.

[0012] Figure 6 This is an illustrative diagram showing an example of a separately specified signal Sd[m].

[0013] Figure 7 This is a block diagram illustrating an example of the structure of the drive signal generation circuit 50.

[0014] Figure 8 This is an exploded perspective view showing an example of the structure of the drive control unit 8.

[0015] Figure 9 This is a top view showing an example of the component arrangement on the transistor substrate 501.

[0016] Figure 10 This is a cross-sectional view showing an example of the construction of the drive control unit 8.

[0017] Figure 11 It is an explanatory diagram showing the thermal conductivity and specific gravity of various metals.

[0018] Figure 12 This is a block diagram illustrating an example of the structure of the drive signal generation circuit 50B according to Modification 3 of the present invention.

[0019] Figure 13 This is a block diagram illustrating an example of the structure of an inkjet printer 1C according to a variation 4 of the present invention.

[0020] Explanation of reference numerals in the attached figures

[0021] 1…Inkjet printer, 2…Control unit, 3…Liquid ejection unit, 5…Drive signal generation unit, 9…Conveying unit, 21…Control circuit, 22…Storage circuit, 31…Supply circuit, 32…Head, 50…Drive signal generation circuit, 51…Analog-to-analog conversion circuit, 52…Transistor pair, 61…Chip body, 64…Grease, 65…Screw, 71…Wiring layer, 72…Insulating layer, 73…Wiring layer, 74…Insulating layer, 75…Substrate, 91…Carriage conveyor motor, 92…Media conveyor motor, 200…Control board, 501…Transistor board, 502…Analog-to-analog conversion circuit board, CC…Electrolytic capacitor, CL1…Transistor cooling mechanism, CL2…Analog-to-analog conversion circuit cooling mechanism, CN1…Board to board connector, CN2…Board to board connector, D…Ejection section, FN1…Fan, FN2…Fan, HS1…Heat sink, HS2…Heat sink, Tr1…Bipolar transistor, Tr2…Bipolar transistor. Detailed Implementation

[0022] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. However, in the drawings, the dimensions and proportions of the parts may be appropriately made different from the actual dimensions. Furthermore, the embodiments described below are preferred examples of the present invention, and therefore various technically preferred limitations are attached, but unless specifically indicated in the following description as a limitation of the invention, the scope of the invention is not limited to these embodiments.

[0023] A. Implementation Method

[0024] The following describes the liquid ejection device using an example inkjet printer 1 that ejects ink to form an image on recording paper PP.

[0025] A.1. Overview of Inkjet Printer 1

[0026] The following is for reference Figures 1 to 3 An example of the structure of the inkjet printer 1 according to this embodiment will be described.

[0027] Figure 1 This is a functional block diagram illustrating an example of the structure of an inkjet printer 1.

[0028] like Figure 1 As shown, a host computer or digital camera supplies printing data Img, representing the image that the inkjet printer 1 should form, to the inkjet printer 1. The inkjet printer 1 performs the printing process of forming the image shown in the printing data Img supplied from the host computer onto recording paper PP.

[0029] like Figure 1As shown, the inkjet printer 1 includes: a control unit 2 for controlling various parts of the inkjet printer 1; a liquid ejection unit 3, which is provided with an ejection section D for ejecting ink onto recording paper PP; a drive signal generation unit 5, which is provided with a drive signal generation circuit 50 for generating a drive signal Com for driving the ejection section D; and a transport unit 9 for transporting the liquid ejection unit 3 and the recording paper PP.

[0030] It should be noted that in this embodiment, the inkjet printer 1 is an example of a "liquid ejection device," the liquid ejection unit 3 is an example of a "liquid ejection head," the ink is an example of a "liquid," and the recording paper PP is an example of a "medium." Furthermore, the structure including the control unit 2 and the drive signal generation unit 5 will be referred to as the "drive control unit 8" below. In this embodiment, the drive control unit 8 is an example of a "drive device."

[0031] In this embodiment, it is envisioned that the inkjet printer 1 has one or more liquid ejection units 3. Specifically, in this embodiment, as an example, it is envisioned that the inkjet printer 1 has four liquid ejection units 3. It should be noted that, for ease of explanation, the following will be as follows: Figure 1 As shown, there is a case where one of the four liquid ejection units 3 is described.

[0032] Furthermore, in this embodiment, as an example, it is envisioned that the drive signal generation unit 5 is equipped with one or more drive signal generation circuits 50 corresponding to one liquid ejection unit 3. Specifically, in this embodiment, it is envisioned that the drive signal generation unit 5 is equipped with two drive signal generation circuits 50 corresponding to one liquid ejection unit 3. That is, in this embodiment, it is envisioned that the drive signal generation unit 5 is equipped with eight drive signal generation circuits 50 corresponding to four liquid ejection units 3. However, the present invention is not limited to this manner. The drive signal generation unit 5 may be equipped with one drive signal generation circuit 50 corresponding to one liquid ejection unit 3, or it may be equipped with three or more drive signal generation circuits 50 corresponding to one liquid ejection unit 3. It should be noted that, for ease of explanation, the following will be used as follows: Figure 1 As shown, there is a case where one of the eight drive signal generation circuits 50 is described.

[0033] The control unit 2 includes a control circuit 21 and a storage circuit 22.

[0034] The storage circuit 22 is configured to include volatile memory such as RAM (Random Access Memory) and non-volatile memory such as ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), or PROM (Programmable Read-Only Memory), and stores various information such as the control program of the inkjet printer 1.

[0035] Furthermore, the control circuit 21 is configured to include one or more CPUs (Central Processing Units). The control circuit 21 can replace a CPU or, in addition to a CPU, possess a programmable logic device such as an FPGA (Field-Programmable Gate Array). Moreover, the control circuit 21 executes the control program for the inkjet printer 1 stored in the storage circuit 22 and performs actions according to the control program, thereby controlling various parts of the inkjet printer 1. Specifically, the control circuit 21 generates signals such as a specified signal SI, a waveform specified signal dCom, a carriage transport control signal SK, and a media transport control signal SB for controlling the actions of various parts of the inkjet printer 1.

[0036] Here, the waveform specification signal dCom is a digital signal that specifies the waveform of the drive signal Com. The drive signal Com is an analog signal used to drive the ejector section D. The specification signal SI is a digital signal that specifies the type of operation of the ejector section D. Specifically, the specification signal SI specifies the type of operation of the ejector section D, such as whether or not ink is ejected from the ejector section D, by specifying whether or not the drive signal Com is supplied to the ejector section D. The carriage transport control signal SK and the media transport control signal SB are signals used to control the transport unit 9.

[0037] It should be noted that in this embodiment, the waveform specification signal dCom is an example of the "first waveform signal".

[0038] During printing, the control unit 2 generates signals such as a specified signal SI to control the liquid ejection unit 3 based on the printing data Img. Additionally, during printing, the control unit 2 generates signals such as a waveform specified signal dCom to control the drive signal generation unit 5. Furthermore, during printing, the control unit 2 generates signals such as a carriage transport control signal SK and a media transport control signal SB to control the transport unit 9. Thus, the control unit 2 controls various parts of the inkjet printer 1 during printing, controlling the transport unit 9 to move the liquid ejection unit 3 and the recording paper PP, while adjusting the presence or absence of ink ejection from the ejection section D and the ink ejection timing, forming an image corresponding to the printing data Img on the recording paper PP.

[0039] like Figure 1 As shown, the liquid ejection unit 3 includes a supply circuit 31 and a head 32.

[0040] The head 32 has M ejector sections D. Here, the value M is a natural number that satisfies "M≥1". It should be noted that, hereinafter, the m-th ejector section D among the M ejector sections D provided in the head 32 is sometimes referred to as ejector section D[m]. Here, the variable m is a natural number that satisfies "1≤m≤M". In addition, hereinafter, when the constituent elements or signals of the inkjet printer 1 correspond to the ejector section D[m] among the M ejector sections D, the reference numerals used to represent the constituent elements or signals are sometimes marked with the superscript [m].

[0041] The supply circuit 31 switches whether to supply the drive signal Com to the ejector section D[m] based on the specified signal SI. Hereinafter, the drive signal Com supplied to the ejector section D[m] in the drive signal Com is sometimes referred to as the supply drive signal Vin[m].

[0042] like Figure 1 As shown, the conveying unit 9 includes a carriage conveying motor 91 and a medium conveying motor 92.

[0043] The carriage conveyor motor 91 conveys the carriage 110 (described later) based on the carriage conveyor control signal SK.

[0044] The media conveying motor 92 conveys recording paper PP based on the media conveying control signal SB.

[0045] Figure 2 This is a perspective view showing an example of the simplified internal structure of an inkjet printer 1.

[0046] like Figure 2As shown, in this embodiment, it is assumed that the inkjet printer 1 is a serial printer. Specifically, when performing printing, the inkjet printer 1 feeds the recording paper PP along the X1 direction while moving the liquid ejection unit 3 along the Y1 direction, which intersects the X1 direction, or the Y2 direction, which is opposite to the Y1 direction, and ejects ink from the liquid ejection unit 3, thereby forming an image corresponding to the printing data Img on the recording paper PP.

[0047] Hereinafter, the X1 direction and its opposite direction, the X2 direction, will be collectively referred to as the "X-axis direction," the Y1 direction, which intersects the X-axis direction, and its opposite direction, the Y2 direction, will be collectively referred to as the "Y-axis direction," and the Z1 direction, which intersects both the X-axis and Y-axis directions, and its opposite direction, the Z2 direction, will be collectively referred to as the "Z-axis direction." In this embodiment, as an example, we will describe the case where the X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other. However, the present invention is not limited to this arrangement. The X-axis direction, the Y-axis direction, and the Z-axis direction may intersect each other. It should be noted that in this embodiment, the Z1 direction is defined as the direction in which ink is ejected from the ejection section D.

[0048] like Figure 2 As shown, the inkjet printer 1 according to this embodiment includes: a housing 100, and a carriage 110 capable of reciprocating within the housing 100 along the Y-axis direction. The carriage 110 is equipped with four liquid ejection units 3, and a drive control unit 8 including a control unit 2 and a drive signal generation unit 5.

[0049] like Figure 2 As shown, in this embodiment, it is envisioned that the carriage 110 is equipped with four ink cartridges 120 corresponding to four colors of ink: blue-green, magenta, yellow, and black. Furthermore, in this embodiment, as described above, it is envisioned that the carriage 110 is equipped with four liquid ejection units 3 corresponding to the four ink cartridges 120. Each ejection section D[m] receives ink from the ink cartridge 120 corresponding to the liquid ejection unit 3 equipped with that ejection section D[m]. Thus, each ejection section D[m] can be filled with the supplied ink internally, and the ink filled inside the ejection section D[m] can be ejected from the nozzle N provided on the ejection section D[m]. It should be noted that the ink cartridges 120 may also be provided on the outside of the carriage 110.

[0050] Furthermore, as described above, the inkjet printer 1 according to this embodiment includes a transport unit 9. For example... Figure 2As shown, the transport unit 9 includes: a carriage transport motor 91 for reciprocating motion of the carriage 110 along the Y-axis direction; a carriage guide shaft 96 supporting the carriage 110 so that it can reciprocate freely along the Y-axis direction; a belt 97 that transports the carriage 110 along the Y-axis direction based on the drive of the carriage transport motor 91; a media transport motor 92 for transporting recording paper PP along the X1 direction; a media transport mechanism 93 that rotates based on the drive of the media transport motor 92 to transport recording paper PP along the X1 direction; and a paper support portion (platen) 95 provided in the Z1 direction of the carriage 110 and supporting the recording paper PP. Therefore, when performing printing processing, the transport unit 9 uses the carriage transport motor 91 to cause the liquid ejection unit 3 to reciprocate along the Y-axis direction along the carriage guide shaft 96 with the carriage 110, and uses the media transport motor 92 to transport the recording paper PP on the paper support portion 95 along the X1 direction, thereby changing the relative position of the recording paper PP with respect to the liquid ejection unit 3, allowing the ink to fall onto the recording paper PP as a whole.

[0051] Figure 3 This is a simplified partial cross-sectional view of the head 32 obtained by cutting through the head 32 including the ejection part D[m].

[0052] like Figure 3As shown, the ejection section D[m] includes a piezoelectric element PZ[m], a cavity CV[m] filled with ink, a nozzle N[m] communicating with the cavity CV[m], and a vibrating plate 321. In the ejection section D[m], the piezoelectric element PZ[m] is driven by a drive signal Vin[m], thereby ejecting ink from the cavity CV[m] from the nozzle N[m]. The cavity CV[m] is a space divided by a cavity plate 324, a nozzle plate 323 on which the nozzle N[m] is formed, and a vibrating plate 321. The cavity CV[m] is connected to a reservoir 325 via an ink supply port 326. The reservoir 325 is connected to an ink cartridge 120 corresponding to the ejection section D[m] via an ink inlet 327. The piezoelectric element PZ[m] has an upper electrode Zu[m], a lower electrode Zd[m], and a piezoelectric element Zm[m] disposed between the upper electrode Zu[m] and the lower electrode Zd[m]. The lower electrode Zd[m] is electrically connected to the power supply line LD, which is set to a predetermined potential VBS. Furthermore, when a drive signal Vin[m] is supplied to the upper electrode Zu[m] and a voltage is applied between the upper electrode Zu[m] and the lower electrode Zd[m], the piezoelectric element PZ[m] displaces along the Z1 and Z2 directions according to the applied voltage, resulting in the piezoelectric element PZ[m] vibrating. The lower electrode Zd[m] is attached to the vibrating plate 321. Therefore, when the piezoelectric element PZ[m] vibrates under the drive signal Vin[m], the vibrating plate 321 also vibrates. Furthermore, the volume of the cavity CV[m] and the pressure within the cavity CV[m] change due to the vibration of the vibrating plate 321, and the ink filled into the cavity CV[m] is ejected from the nozzle N[m].

[0053] A.2. Structure and operation of liquid ejection unit 3

[0054] The following is for reference Figures 4 to 6 An example of the structure and operation of the liquid ejection unit 3 will be explained.

[0055] Figure 4 This is a block diagram showing an example of the structure of the liquid ejection unit 3.

[0056] like Figure 4 As shown, the liquid ejection unit 3 includes a supply circuit 31 and a head 32. Additionally, the liquid ejection unit 3 includes a wiring LC that receives a drive signal Com from the drive signal generation unit 5.

[0057] like Figure 4 As shown, the supply circuit 31 includes M switches WS[1] to WS[M] that correspond one-to-one with the M ejector sections D[1] to D[M], and a connection state specifying circuit 310 that specifies the connection state of each switch.

[0058] The connection state specifying circuit 310 generates a connection state specifying signal QS[m] to specify the opening and closing of switch WS[m] based on at least a portion of the specifying signal SI, latching signal LAT, changing signal CH, and clock signal CLK supplied from control unit 2.

[0059] The switch WS[m] switches the connection between the wiring LC and the upper electrode Zu[m] of the piezoelectric element PZ[m] located in the ejector section D[m] based on the connection state specification signal QS[m]. In this embodiment, the switch WS[m] is turned on when the connection state specification signal QS[m] is high and turned off when the connection state specification signal QS[m] is low. When the switch WS[m] is on, the drive signal Com supplied to the wiring LC is supplied as the drive signal Vin[m] to the upper electrode Zu[m] of the ejector section D[m].

[0060] Figure 5 This is a timing diagram showing an example of various signals, such as the drive signal Com, supplied to the liquid ejection unit 3.

[0061] like Figure 5 As shown, when performing printing processing, the inkjet printer 1 has one or more unit periods TP set as the operating period of the inkjet printer 1. In this embodiment, the inkjet printer 1 can drive each ejection section D[m] for printing processing within each unit period TP.

[0062] like Figure 5 As shown, control unit 2 outputs a latched signal LAT with a pulse PLL. Therefore, control unit 2 defines the unit period TP as the period from the rising edge of the pulse PLL to the rising edge of the next pulse PLL. Additionally, control unit 2 outputs a change signal CH with a pulse PLC within the unit period TP. Furthermore, control unit 2 divides the unit period TP into a drive period TQ1 from the rising edge of the pulse PLL to the rising edge of the pulse PLC, and a drive period TQ2 from the rising edge of the pulse PLC to the rising edge of the pulse PLL.

[0063] like Figure 5As shown, the designation signal SI includes M individual designation signals Sd[1] to Sd[M] corresponding one-to-one with the M ejector sections D[1] to D[M]. When the inkjet printer 1 performs printing processing, the individual designation signal Sd[m] designates the driving mode of the ejector section D[m] within each unit period TP. Before each unit period TP, the control unit 2 supplies the designation signal SI, which includes the M individual designation signals Sd[1] to Sd[M], to the connection state designation circuit 310 synchronously with the clock signal CLK. Furthermore, within this unit period TP, the connection state designation circuit 310 generates a connection state designation signal QS[m] based on the individual designation signal Sd[m].

[0064] It should be noted that in this embodiment, it is envisioned that within a unit period TP of the printing process, the ejector section D[m] can form any one of the following: a large dot composed of ink amount ξ1, a medium dot composed of ink amount ξ2 less than ink amount ξ1, or a small dot composed of ink amount ξ3 less than ink amount ξ2.

[0065] Figure 6 This is an explanatory diagram used to illustrate an example of a single specified signal Sd[m].

[0066] like Figure 6 As shown, in this embodiment, the signal Sd[m] can take any one of the following four values ​​within the unit period TP of the printing process: "1" for designating the ejector part D[m] as a large dot forming ejector part DP-1, "2" for designating the ejector part D[m] as a medium dot forming ejector part DP-2, "3" for designating the ejector part D[m] as a small dot forming ejector part DP-3, and "4" for designating the ejector part D[m] as a dot non-forming ejector part DP-4.

[0067] Here, the large dot-forming ejection section DP-1 refers to the ejection section D that forms large dots within a unit period TP. The midpoint-forming ejection section DP-2 refers to the ejection section D that forms midpoints within a unit period TP. The small dot-forming ejection section DP-3 refers to the ejection section D that forms small dots within a unit period TP. The non-dot-forming ejection section DP-4 refers to the ejection section D that does not form dots within a unit period TP.

[0068] return Figure 5 Please provide an explanation.

[0069] like Figure 5 As shown, in this embodiment, the drive signal Com has a waveform PA1 set during drive period TQ1 and a waveform PA2 set during drive period TQ2.

[0070] Waveform PA1 is the waveform that returns from potential V0 to potential V0 after passing through potential VLA1 (lower than potential V0) and potential VHA1 (higher than potential V0). Waveform PA1 is determined such that when a supply drive signal Vin[m] with waveform PA1 is supplied to the ejection section D[m], ink equivalent to ink amount φ1 is ejected from the ejection section D[m]. Waveform PA2 is the waveform that returns from potential V0 to potential V0 after passing through potential VLA2 (lower than potential V0) and potential VHA2 (higher than potential V0). Waveform PA1 is determined such that when a supply drive signal Vin[m] with waveform PA2 is supplied to the ejection section D[m], ink equivalent to ink amount φ2 is ejected from the ejection section D[m]. It should be noted that in this embodiment, it is assumed that ink amount ξ1 is equivalent to the sum of ink amount φ1 and ink amount φ2, ink amount ξ2 is equivalent to ink amount φ1, and ink amount ξ3 is equivalent to ink amount φ2.

[0071] Furthermore, in this embodiment, as an example, it is envisioned that when the potential of the supply drive signal Vin[m] supplied to the ejection section D[m] is high, the volume of the cavity CV[m] provided by the ejection section D[m] is smaller compared to the case of a low potential. Therefore, when the ejection section D[m] is driven by the supply drive signal Vin[m] having a waveform PA1, etc., the ink in the ejection section D[m] is ejected from the nozzle N[m] by the change in the potential of the supply drive signal Vin[m] from a low potential to a high potential.

[0072] like Figure 6 As shown, when the separately specified signal Sd[m] indicates that the value "1" is set for the large dot forming nozzle DP-1 of the nozzle within the unit period TP, the connection state specifying circuit 310 sets the connection state specifying signal QS[m] to a high level during the driving period TQ1 and driving period TQ2. In this case, the switch WS[m] is turned on during the driving period TQ1 and driving period TQ2. Therefore, the nozzle D[m] is driven by the supply driving signal Vin[m] with waveforms PA1 and PA2 within the unit period TP, and ejects ink equivalent to the ink amount ξ1 of the large dot.

[0073] Furthermore, when the separately specified signal Sd[m] indicates a value "2" for designating the ejector section D[m] as the midpoint to form the ejector section DP-2 within the unit period TP, the connection state specifying circuit 310 sets the connection state specifying signal QS[m] to a high level during the driving period TQ1. In this case, the switch WS[m] is turned on during the driving period TQ1. Therefore, the ejector section D[m] is driven by the supply driving signal Vin[m] with waveform PA1 within the unit period TP, ejecting ink equivalent to the ink amount ξ2 at the midpoint.

[0074] Furthermore, when the separately designated signal Sd[m] indicates that the value "3" of the small dot formation ejection part D[m] is designated as the small dot formation ejection part DP-3 within the unit period TP, the connection state designation circuit 310 sets the connection state designation signal QS[m] to a high level during the driving period TQ2. In this case, the switch WS[m] is turned on during the driving period TQ2. Therefore, the ejection part D[m] is driven by the supply drive signal Vin[m] with waveform PA2 within the unit period TP, ejecting ink equivalent to the ink amount ξ3 of the small dot.

[0075] Furthermore, when the separately specified signal Sd[m] indicates that the ejector section D[m] is specified as the value "4" for the non-forming ejector section DP-4 within the unit period TP, the connection state specifying circuit 310 sets the connection state specifying signal QS[m] to a low level throughout the unit period TP. In this case, the switch WS[m] is open throughout the unit period TP. Therefore, the ejector section D[m] is not driven by the supply drive signal Vin[m] within the unit period TP, and no ink is ejected.

[0076] A.3. Structure of the drive signal generation circuit 50

[0077] The following is for reference Figure 7 An example of the structure of the drive signal generation circuit 50 provided in the drive signal generation unit 5 will be described.

[0078] Figure 7 This is a block diagram showing an example of the circuit configuration of the drive signal generation circuit 50.

[0079] like Figure 7 As shown, the drive signal generation circuit 50 includes an analog-to-analog converter circuit 51, a transistor pair 52, and an electrolytic capacitor CC. The drive signal generation circuit 50 generates an analog drive signal Com with the waveform specified by the digital waveform specification signal dCom. Specifically, the drive signal generation circuit 50 generates the drive signal Com, for example, by performing A / B stage amplification on the input signal obtained from the analog-to-analog conversion of the waveform specification signal dCom.

[0080] The analog-to-analog converter 51 outputs a waveform-specific signal QB, which includes a base supply signal QB1 and a base supply signal QB2, based on the digital waveform-specific signal dCom. Specifically, the analog-to-analog converter 51 converts the waveform-specific signal dCom into an analog input signal and generates an analog signal representing a potential based on the input signal, namely the base supply signal QB1, and an analog signal representing a potential based on the input signal but lower than the base supply signal QB1, namely the base supply signal QB2. Furthermore, the analog-to-analog converter 51 outputs the base supply signal QB1 from output terminal Tn1 and the base supply signal QB2 from output terminal Tn2.

[0081] It should be noted that in this embodiment, the waveform specification signal QB is an example of a "second waveform signal".

[0082] Transistor pair 52 is a so-called push-pull circuit with an NPN bipolar transistor Tr1 and a PNP bipolar transistor Tr2, which generates a drive signal Com based on the basic supply signal QB1 and the basic supply signal QB2.

[0083] In bipolar transistor Tr1, the base (B) is electrically connected to the output terminal Tn1, and a basic supply signal QB1 is supplied from the output terminal Tn1. Additionally, in bipolar transistor Tr1, the collector (C) is electrically connected to the power supply line LH, which is set to the power supply potential VHV, and the emitter (E) is electrically connected to the wiring LC used to supply the drive signal Com. It should be noted that bipolar transistor Tr1 is turned on, for example, when the potential of the basic supply signal QB1 rises, resulting in a rise in the potential of the drive signal Com. Furthermore, bipolar transistor Tr1 is turned off, for example, when the potential of the basic supply signal QB1 is constant, and when the potential of the basic supply signal QB1 falls.

[0084] In bipolar transistor Tr2, the base (B) is electrically connected to the output terminal Tn2, and a basic supply signal QB2 is supplied from the output terminal Tn2. Additionally, in bipolar transistor Tr2, the collector (C) is electrically connected to ground, and the emitter (E) is electrically connected to the LC wiring used to supply the drive signal Com. It should be noted that bipolar transistor Tr2 is turned on when the potential of the basic supply signal QB2 decreases, resulting in a decrease in the potential of the drive signal Com. Furthermore, bipolar transistor Tr2 is turned off when the potential of the basic supply signal QB2 is constant and when the potential of the basic supply signal QB2 increases.

[0085] Electrolytic capacitor CC is a capacitor used to supply current to transistor Tr1. Specifically, of the two electrodes of electrolytic capacitor CC, one electrode is electrically connected to the power supply line LH and the collector of bipolar transistor Tr1, and the other electrode is electrically connected to the ground line.

[0086] A.4. Structure of the drive control unit 8

[0087] The following is for reference Figures 8 to 11 An example of the structure of the drive control unit 8 will be described.

[0088] Figure 8 This is an exploded perspective view showing an example of the structure of the drive control unit 8.

[0089] like Figure 8 As shown, the drive control unit 8 includes: a control board 200, a transistor board 501, an analog-to-digital converter board 502, a transistor cooling mechanism CL1, and an analog-to-digital converter cooling mechanism CL2. It should be noted that, in this embodiment, as an example, it is envisioned that the control board 200, the transistor board 501, and the analog-to-digital converter board 502 are arranged to extend on a plane with the Z1 direction as the normal direction.

[0090] It should be noted that in this embodiment, the transistor substrate 501 is an example of a "first substrate", the analog conversion circuit substrate 502 is an example of a "second substrate", and the control substrate 200 is an example of a "third substrate".

[0091] A control circuit 21 and a storage circuit 22 are provided on the control board 200. It should be noted that the control unit 2 mentioned above includes the control board 200, the control circuit 21, and the storage circuit 22.

[0092] A pair of transistors 52, including bipolar transistors Tr1 and Tr2, is provided on the transistor substrate 501 in the drive signal generation circuit 50. Specifically, in this embodiment, it is envisioned that the pair of transistors 52 is provided on the surface PL11, one of the multiple surfaces of the transistor substrate 501, with the Z2 direction as the normal direction. It should be noted that, as described above, in this embodiment, it is envisioned that the drive signal generation circuit 50 has eight drive signal generation circuits 50. Therefore, in this embodiment, eight bipolar transistors Tr1 and eight bipolar transistors Tr2 of the eight transistor pairs are provided on the surface PL11 of the transistor substrate 501. It should be noted that, hereinafter, bipolar transistors Tr1 and Tr2 are sometimes collectively referred to as bipolar transistors Tr.

[0093] An analog conversion circuit 51 and an electrolytic capacitor CC from a drive signal generation circuit 50 are provided on the analog conversion circuit substrate 502. Specifically, in this embodiment, it is envisioned that the analog conversion circuit 51 and the electrolytic capacitor CC are provided on surface PL21, one of the multiple surfaces of the analog conversion circuit substrate 502, with the Z2 direction as the normal direction. It should be noted that, as described above, in this embodiment, it is envisioned that the drive signal generation circuit 50 includes eight drive signal generation circuits 50. Therefore, in this embodiment, eight analog conversion circuits 51 and eight electrolytic capacitors CC are provided on the analog conversion circuit substrate 502.

[0094] The transistor cooling mechanism CL1 includes a heat sink HS1 and a fan FN1. It should be noted that in this embodiment, the transistor cooling mechanism CL1 is an example of a "first cooling mechanism".

[0095] The heat sink HS1 is connected to the transistor substrate 501 and dissipates heat generated in the transistor pair 52 provided on the transistor substrate 501. In this embodiment, it is envisioned that the heat sink HS1 is connected to PL12 with the Z1 direction as the normal direction among the multiple surfaces of the transistor substrate 501.

[0096] It should be noted that, as detailed later, in this embodiment, the transistor substrate 501 has an aluminum substrate 75. Additionally, in this embodiment, the heat sink HS1 is formed of aluminum.

[0097] Fan FN1 is connected to heat sink HS1 to cool it. However, fan FN1 can also be connected to transistor substrate 501 to cool it. It should be noted that in this embodiment, it is envisioned that fan FN1 remains operational during the period when inkjet printer 1 performs printing processing and drive signal generation circuit 50 generates drive signal Com. For example, in this embodiment, fan FN1 may also remain operational when control unit 2 supplies waveform specification signal dCom to drive signal generation circuit 50.

[0098] The analog converter circuit cooling mechanism CL2 includes a heat sink HS2 and a fan FN2. It should be noted that in this embodiment, the analog converter circuit cooling mechanism CL2 is an example of a "second cooling mechanism".

[0099] The heat sink HS2 is connected to the analog-to-digital converter circuit board 502 and dissipates heat generated in the analog-to-digital converter circuit 51 provided on the analog-to-digital converter circuit board 502. In this embodiment, it is envisioned that the heat sink HS2 is connected to surface PL21, one of the multiple surfaces of the analog-to-digital converter circuit board 502. However, the heat sink HS2 may also be configured to be directly connected to the analog-to-digital converter circuit 51 provided on surface PL21 of the analog-to-digital converter circuit board 502.

[0100] It should be noted that, as detailed later, in this embodiment, the analog conversion circuit board 502 has an aluminum substrate. Furthermore, in this embodiment, the heat sink HS2 is formed of aluminum.

[0101] Fan FN2 is connected to heat sink HS2 and cools heat sink HS2. Alternatively, fan FN2 can be connected to analog conversion circuit board 502 and cool analog conversion circuit board 502. Additionally, fan FN2 can be connected to analog conversion circuit 51 and cool analog conversion circuit 51. It should be noted that in this embodiment, it is envisioned that fan FN2 remains operational during the period when inkjet printer 1 performs printing processing and drive signal generation circuit 50 generates drive signal Com. For example, in this embodiment, fan FN2 may also remain operational when control unit 2 supplies waveform specification signal dCom to drive signal generation circuit 50.

[0102] The transistor substrate 501 and the analog-to-digital converter circuit substrate 502 are connected via a substrate-to-substrate connector CN1. Specifically, the substrate-to-substrate connector CN1 includes a socket CN11 fixed to surface PL11 of the transistor substrate 501; and a plug CN12 fixed to surface PL22 of the analog-to-digital converter circuit substrate 502, which is normal to the Z1 direction, and is capable of engaging with the socket CN11. The substrate-to-substrate connector CN1 secures the transistor substrate 501 and the analog-to-digital converter circuit substrate 502 by engaging the socket CN11 and the plug CN12, and transmits signals between the transistor substrate 501 and the analog-to-digital converter circuit substrate 502.

[0103] The analog-to-analog converter circuit board 502 and the control board 200 are connected via a substrate-to-substrate connector CN2. Specifically, the substrate-to-substrate connector CN2 includes: a socket CN21 fixed to surface PL21 of the analog-to-analog converter circuit board 502; and a plug CN22 fixed to one of the multiple surfaces of the control board 200 with the Z1 direction as its normal direction, and capable of engaging with the socket CN21. The substrate-to-substrate connector CN2 secures the analog-to-analog converter circuit board 502 and the control board 200 by engaging the socket CN21 and the plug CN22, and transmits signals between the analog-to-analog converter circuit board 502 and the control board 200.

[0104] Figure 9 This is a top view showing an example of the arrangement of various electronic components in the transistor substrate 501 when viewed from above along the Z1 direction.

[0105] like Figure 9 As shown, the transistor substrate 501 includes: a long side LY1 extending along the Y1 direction and located at the end of the transistor substrate 501 in the X2 direction; a long side LY2 extending along the Y1 direction opposite to the long side LY1 and located at the end of the transistor substrate 501 in the X1 direction; a short side LX1 extending along the X1 direction and located at the end of the transistor substrate 501 in the Y2 direction; and a short side LX2 extending along the X1 direction opposite to the short side LX1 and located at the end of the transistor substrate 501 in the Y1 direction. It should be noted that in this embodiment, the long sides LY1 and LY2 have approximately the same length, and the short sides LX1 and LX2 have approximately the same length, with the long side LY1 being longer than the short side LX1. Here, "approximately the same" includes not only cases where they are completely identical, but also cases where they are considered identical if an error is considered. For example, "approximately the same" can also mean identical in design. Furthermore, "approximately the same" can also include the concept of cases where they are considered identical if an error of approximately 5% is considered.

[0106] When the transistor substrate 501 is viewed from above along the Z1 direction, the surface PL11 of the transistor substrate 501 is divided into an end region AT1 including a long side LY1, an end region AT2 including a long side LY2, and a central region AM disposed between the end regions AT1 and AT2.

[0107] like Figure 9As shown, in this embodiment, it is envisioned that the sixteen bipolar transistors Tr of the drive signal generation circuit 50 are located in the end region AT1 or the end region AT2. Specifically, in this embodiment, it is envisioned that eight of the sixteen bipolar transistors Tr of the drive signal generation circuit 50 are located in the end region AT1, and the remaining eight are located in the end region AT2. That is, in this embodiment, it is envisioned that the sixteen bipolar transistors Tr of the drive signal generation circuit 50 are arranged along the long side LY1 or the long side LY2. Therefore, according to this embodiment, compared with the case where the bipolar transistors Tr are located in the central region AM, heat dissipation from the bipolar transistors Tr can be efficiently achieved from the long side LY1 or the long side LY2.

[0108] In addition, such as Figure 9 As shown, in this embodiment, the substrate-to-substrate connector CN1 is conceived to be located in the central region AM. Therefore, according to this embodiment, compared with the method of providing the substrate-to-substrate connector CN1 in the end region AT1 or the end region AT2, it is possible to reduce the variation in the relative position and relative posture between the transistor substrate 501 and the analog conversion circuit substrate 502, and to stably connect the transistor substrate 501 and the analog conversion circuit substrate 502 through the substrate-to-substrate connector CN1.

[0109] Figure 10 This is a cross-sectional view showing an example of the cross-sectional configuration of a transistor substrate 501, a bipolar transistor Tr, and a heat sink HS1.

[0110] like Figure 10 As shown, the bipolar transistor Tr includes a chip body 61, a base 62B, a collector 62C, and an emitter 62E. It should be noted that... Figure 10 Although the collector 62C and emitter 62E are not shown in the diagram, the collector 62C is located, for example, in a position closer to the base 62B in the X1 direction, and the emitter 62E is located, for example, in a position closer to the base 62B in the X2 direction.

[0111] like Figure 10 As shown, the transistor substrate 501 includes a wiring layer 71, an insulating layer 72, a wiring layer 73, an insulating layer 74, and a substrate 75.

[0112] The wiring layer 71 includes: an insulating resist 712, wiring 711B electrically connected to the base 62B via wiring 63B, wiring 711C electrically connected to the collector 62C via wiring 63C (not shown), and wiring 711E electrically connected to the emitter 62E via wiring 63E (not shown). It should be noted that in... Figure 10Although wiring 711C and wiring 711E are not shown in the diagram, wiring 711C is configured, for example, in a direction X1 closer to wiring 711B, insulated from wiring 711B, and wiring 711E is configured, for example, in a direction X2 closer to wiring 711B, insulated from wiring 711B. It should be noted that the surface facing the Z2 direction in the wiring layer 71 corresponds to surface PL11.

[0113] The insulating layer 72 includes: an insulating portion 722 formed of an insulating material, a connecting wire 721B electrically connected to the wiring 711B, a connecting wire 721C electrically connected to the wiring 711C, and a connecting wire 721E electrically connected to the wiring 711E. It should be noted that in... Figure 10 Although the connecting wires 721C and 721E are not shown in the diagram, the connecting wire 721C is configured, for example, in a direction X1 closer to the connecting wire 721B, in a state that is insulated from the connecting wire 721B, and the connecting wire 721E is configured, for example, in a direction X2 closer to the connecting wire 721B, in a state that is insulated from the connecting wire 721B.

[0114] The wiring layer 73 includes: an insulating portion 732 formed of an insulating material, a wiring 731B electrically connected to the connecting wiring 721B, a wiring 731C electrically connected to the connecting wiring 721C, and a wiring 731E electrically connected to the connecting wiring 721E. It should be noted that in... Figure 10 Although wiring 731C and wiring 731E are not shown in the diagram, wiring 731C is configured, for example, in a direction X1 closer to wiring 731B, in a state of being insulated from wiring 731B, and wiring 731E is configured, for example, in a direction X2 closer to wiring 731B, in a state of being insulated from wiring 731B.

[0115] The insulating layer 74 electrically insulates the wiring 731B, wiring 731C, and wiring 731E disposed on the wiring layer 73 from the substrate 75.

[0116] The substrate 75 is formed of aluminum. In this embodiment, it is envisioned that a heat sink HS1 is connected to the substrate 75 via grease 64. Alternatively, the heat sink HS1 may be connected to the substrate 75 via a heat sink fin. It should be noted that the surface facing the Z1 direction among the surfaces of the substrate 75 corresponds to surface PL12.

[0117] like Figure 10 As shown, the bipolar transistor Tr is configured such that the surface 600 with the largest area of ​​the surface of the bipolar transistor Tr is connected to the surface PL11 of the wiring layer 71 of the transistor substrate 501.

[0118] Furthermore, the bipolar transistor Tr is fixed to the transistor substrate 501 by screws 65. Specifically, in this embodiment, the bipolar transistor Tr is fixed to the transistor substrate 501 and the heat sink HS1 by screws 65 that penetrate the transistor substrate 501. It should be noted that in this embodiment, it is assumed that the screws 65 are made of metal. It should also be noted that the screws 65 can be non-metallic. However, it is preferable that the screws 65 are formed of a material with higher thermal conductivity than the resist 712, insulating portion 722, insulating portion 732, and insulating layer 74 in the transistor substrate 501.

[0119] It should be noted that, as described above, in this embodiment, the substrate 75 of the transistor substrate 501 is formed of aluminum. Additionally, in this embodiment, the heat sink HS1 is formed of aluminum.

[0120] Figure 11 It is a graph showing the thermal conductivity and specific gravity of various metals.

[0121] like Figure 11 As shown, copper has a thermal conductivity of 398 W / mK. Therefore, compared to the thermal conductivity of aluminum (236 W / mK), iron (67 W / mK), and stainless steel (16 W / mK), copper has a high thermal conductivity. That is, by using a copper substrate as the transistor substrate 501 and a copper substrate as the analog conversion circuit substrate 502, heat generated in the drive signal generation unit 5 can be efficiently dissipated. It should be noted that while materials with higher thermal conductivity than copper, such as silver (398 W / mK) and diamond (1000 W / mK), exist, their high cost makes them impractical for use as the substrate of the drive signal generation unit 5. Therefore, using a copper substrate as the substrate of the drive signal generation unit 5 has been the conventional practice.

[0122] On the other hand, such as Figure 11 As shown, the specific gravity of aluminum is 2.7 g / cm³. 3 Therefore, its specific gravity compared to copper is 8.9 g / cm³. 3 The specific gravity of iron is 7.8 g / cm³. 3 And the specific gravity of stainless steel is 7.9 g / cm³. 3In comparison, aluminum has a lower specific gravity. Therefore, the drive signal generation unit 5 according to this embodiment can be made lighter than conventional drive signal generation units that use copper substrates. As a result, when the drive signal generation unit 5 according to this embodiment is mounted on the carriage 110 and moved, the load on the carriage transport motor 91 of the carriage 110 can be reduced. That is, compared with conventional drive signal generation units that use copper substrates, the drive signal generation unit 5 according to this embodiment can extend the lifespan of the carriage transport motor 91 and reduce the power consumption involved in driving the carriage transport motor 91.

[0123] Furthermore, as mentioned above, although aluminum has a lower thermal conductivity than copper, it has a higher thermal conductivity than iron and stainless steel. Therefore, according to the drive signal generation unit 5 of this embodiment, it is possible to simultaneously reduce the load borne by the carriage transport motor 91 of the drive carriage 110 and achieve efficient heat dissipation in the drive signal generation unit 5.

[0124] Furthermore, a heat sink is typically installed in the drive signal generation unit 5, which generates a lot of heat, to improve its heat dissipation. The heat sink is usually made of aluminum. Therefore, when an aluminum heat sink is installed in a drive signal generation unit that uses a copper substrate, the possibility of corrosion at the boundary between the copper substrate and the aluminum heat sink increases. Therefore, in conventional drive signal generation units using a copper substrate, heat sink fins are usually sandwiched between the copper substrate and the aluminum heat sink to prevent corrosion at the boundary when an aluminum heat sink is installed. Therefore, in conventional drive signal generation units using a copper substrate, issues such as increasing the size of the drive signal generation unit, increasing its cost, and increasing the number of components in the drive signal generation unit sometimes arise.

[0125] In contrast, the drive signal generation unit 5 according to this embodiment uses an aluminum substrate 75 as the transistor substrate 501. Therefore, in the drive signal generation unit 5 according to this embodiment, corrosion at the boundary between the aluminum substrate 75 and the aluminum heat sink HS1 is not a problem. Therefore, in the drive signal generation unit 5 according to this embodiment, it is not necessary to sandwich a heat sink between the transistor substrate 501 and the heat sink HS1; only lubricating grease 64 is sandwiched between the transistor substrate 501 and the heat sink HS1. As a result, compared with conventional drive signal generation units using copper substrates, the drive signal generation unit 5 according to this embodiment can achieve miniaturization, cost reduction, and a reduction in the number of components.

[0126] It should be noted that aluminum, as a base metal, has the second highest production volume after iron, and its reserves are considered higher than iron's relative demand. Furthermore, aluminum is considered to be a more recyclable metal compared to copper. On the other hand, copper resources are finite, and it is projected that by 2050, copper consumption will exceed current reserves. In contrast, in this embodiment, the drive signal generation unit 5 uses an aluminum substrate 75 formed of aluminum. Therefore, according to this embodiment, compared to using a copper substrate for the drive signal generation unit 5, the environmental burden can be reduced, and the impact on future copper shortages can be minimized.

[0127] A.5. Summary of Implementation Methods

[0128] As described above, according to this embodiment, since an aluminum substrate with an aluminum base is used as the transistor substrate 501 and the analog conversion circuit substrate 502, the drive signal generation unit 5 can be made lighter compared to conventional drive signal generation units using copper substrates. Therefore, according to this embodiment, when the drive signal generation unit 5 is mounted on the carriage 110 and moved, the load on the carriage transport motor 91 driving the carriage 110 can be reduced. In other words, compared to conventional drive signal generation units using copper substrates, the drive signal generation unit 5 according to this embodiment can achieve a longer lifespan for the carriage transport motor 91 and a reduction in the power consumption related to driving the carriage transport motor 91.

[0129] Furthermore, in the drive signal generation unit 5 according to this embodiment, an aluminum substrate 75 is used as the transistor substrate 501. Therefore, corrosion at the boundary between the aluminum substrate 75 and the aluminum heat sink HS1 in the drive signal generation unit 5 according to this embodiment is not a problem. Therefore, in the drive signal generation unit 5 according to this embodiment, it is not necessary to sandwich a heat sink between the transistor substrate 501 and the heat sink HS1. Similarly, in the drive signal generation unit 5 according to this embodiment, it is not necessary to sandwich a heat sink between the analog conversion circuit substrate 502 and the heat sink HS2. Therefore, compared with conventional drive signal generation units using copper substrates, the drive signal generation unit 5 according to this embodiment can achieve miniaturization, cost reduction, and a reduction in the number of components.

[0130] Furthermore, in the drive signal generation unit 5 according to this embodiment, the analog conversion circuit substrate 502 with analog conversion circuit 51 and the transistor substrate 501 with transistor pair 52 are set as separate substrates. Therefore, compared with the method of setting transistor pair 52 and analog conversion circuit 51 on the same substrate, the drive signal generation unit 5 according to this embodiment can suppress the heat transfer from transistor pair 52 to analog conversion circuit 51 and can suppress the overheating of analog conversion circuit 51.

[0131] Furthermore, in the drive signal generation unit 5 according to this embodiment, the control substrate 200 with the control circuit 21 and the transistor substrate 501 with the transistor pair 52 are separate substrates. Therefore, compared with the method of placing the transistor pair 52 and the control circuit 21 on the same substrate, the drive signal generation unit 5 according to this embodiment can suppress the transfer of heat from the transistor pair 52 to the control circuit 21 and can suppress the overheating of the control circuit 21.

[0132] Furthermore, in the drive signal generation unit 5 according to this embodiment, an analog conversion circuit cooling mechanism CL2 for cooling the analog conversion circuit substrate 502, which is equipped with the analog conversion circuit 51, is provided separately from the transistor cooling mechanism CL1 for cooling the transistor substrate 501 on which the transistor pair 52 is provided. Therefore, compared with the method of using the transistor cooling mechanism CL1, which also cools the transistor substrate 501, the drive signal generation unit 5 according to this embodiment can efficiently cool the analog conversion circuit substrate 502. Therefore, even when the drive signal Com is a large amplitude signal and the base current supplied from the analog conversion circuit 51 to the transistor pair 52 is a large current, the drive signal generation unit 5 according to this embodiment can effectively suppress the heat generation in the analog conversion circuit 51.

[0133] Furthermore, in the drive signal generation unit 5 according to this embodiment, the transistor substrate 501 and the analog-to-digital converter circuit substrate 502 are fixed via the substrate-to-substrate connector CN1. Therefore, according to this embodiment, compared to a method where the transistor substrate 501 and the analog-to-digital converter circuit substrate 502 are connected, for example, via a flexible printed circuit board, even when the drive signal generation unit 5 is mounted on the carriage 110 and moves inside the inkjet printer 1, the generation of relative positional offset between the transistor substrate 501 and the analog-to-digital converter circuit substrate 502, as well as the generation of relative posture offset between the transistor substrate 501 and the analog-to-digital converter circuit substrate 502, can be suppressed. Thus, according to this embodiment, the transistor substrate 501 and the analog-to-digital converter circuit substrate 502 can be stably connected. Similarly, according to this embodiment, the analog-to-digital converter circuit substrate 502 and the control board 200 can be stably connected.

[0134] B. Variations

[0135] The above methods can be varied in many ways. The following examples illustrate specific variations. Two or more methods selected from the following examples can be appropriately combined without contradiction. It should be noted that in the variations illustrated below, elements with equivalent function and implementation method use the reference numerals from the accompanying drawings mentioned above, and detailed descriptions are appropriately omitted.

[0136] B.1. Variation Example 1

[0137] In the above embodiments, although the example illustrates an aluminum substrate formed of aluminum as the substrate of the analog conversion circuit board 502, the present invention is not limited to this method. The analog conversion circuit board 502 may also be a copper substrate formed of copper as the substrate. The analog conversion circuit board 502 may also be a metal substrate formed of metal as the substrate.

[0138] Furthermore, although the above embodiments illustrate the case where the heat sink HS2 is formed of aluminum, the present invention is not limited to this method. The heat sink HS2 can also be formed of copper. It should be noted that corrosion between the heat sink HS2 and the analog conversion circuit board 502 can also be suppressed by using a copper substrate as the analog conversion circuit board 502 and forming the heat sink HS2 with copper.

[0139] B.2. Variation Example 2

[0140] In the above embodiments and variations 1, although the example illustrates a case where the transistor substrate 501 is an aluminum substrate with the substrate 75 formed of aluminum, the present invention is not limited to this configuration. The transistor substrate 501 may also be a copper substrate with the substrate 75 formed of copper. The transistor substrate 501 may also be a metal substrate with the substrate formed of metal.

[0141] Furthermore, although the example heat sink HS1 has been described as being made of aluminum in the above embodiments, the present invention is not limited to this method. The heat sink HS1 can also be made of copper. It should be noted that corrosion between the heat sink HS1 and the substrate 75 can also be suppressed by using a copper substrate as the transistor substrate 501 and forming the heat sink HS1 from copper.

[0142] B.3. Variation Example 3

[0143] In the above embodiments and variations 1 and 2, although the examples illustrate a configuration where a transistor pair 52 is provided in the drive signal generation circuit 50 corresponding to an analog-to-digital converter 51, the present invention is not limited to this configuration. Multiple transistor pairs 52 may also be provided corresponding to an analog-to-digital converter 51.

[0144] Figure 12 This is a block diagram illustrating an example of the circuit configuration of the drive signal generation circuit 50B according to this modification. It should be noted that the inkjet printer according to this modification is configured similarly to the inkjet printer 1 according to the embodiment, except that it has a drive signal generation circuit 50B instead of a drive signal generation circuit 50.

[0145] like Figure 12 As shown, the drive signal generation circuit 50B differs from the drive signal generation circuit 50 in the following aspects: it replaces the analog conversion circuit 51B; it replaces the transistor pair 52 with multiple transistor pairs 52[1] to 52[K]; and it replaces the electrolytic capacitor CC with multiple electrolytic capacitors CC[1] to CC[K]. Here, the value K is a natural number that satisfies "K≥1". It should be noted that, hereinafter, the kth transistor pair 52 among the K transistor pairs 52 provided in the drive signal generation circuit 50B is sometimes referred to as transistor pair 52[k]. In addition, hereinafter, the kth electrolytic capacitor CC among the K electrolytic capacitors CC provided in the drive signal generation circuit 50B is sometimes referred to as electrolytic capacitor CC[k]. Here, the variable k is a natural number that satisfies "1≤k≤K". It should be noted that, hereinafter, as Figure 12 As shown in the example, the value K is "2".

[0146] The analog-to-analog converter 51B outputs a waveform-specific signal QB[k] based on the digital waveform-specific signal dCom[k], which includes the basic supply signal QB1[k] and the basic supply signal QB2[k]. Furthermore, the analog-to-analog converter 51B outputs the basic supply signal QB1[k] from the output terminal Tn1[k] and the basic supply signal QB2[k] from the output terminal Tn2[k].

[0147] It should be noted that, in this modified example, although it is assumed that the waveform designation signal dCom[1] and the waveform designation signal dCom[2] are signals that designate different waveforms, the present invention is not limited to such an approach. The waveform designation signal dCom[1] and the waveform designation signal dCom[2] can also be signals that designate the same waveform.

[0148] In addition, in this modified example, it is conceivable that the analog conversion circuit 51B generates waveform designation signals QB[1] to QB[K] based on waveform designation signals dCom[1] to dCom[K], but the present invention is not limited to such an approach. The analog conversion circuit 51B may also generate waveform designation signals QB[1] to QB[K] with approximately the same waveform based on a single waveform designation signal dCom.

[0149] Transistor pair 52[k] has an NPN type bipolar transistor Tr1[k] and a PNP type bipolar transistor Tr2[k], and generates a drive signal Com[k] based on the basic supply signal QB1[k] and the basic supply signal QB2[k].

[0150] In the bipolar transistor Tr1[k], the base (B) is electrically connected to the output terminal Tn1[k], and a base supply signal QB1[k] is supplied from the output terminal Tn1[k]. Additionally, in the bipolar transistor Tr1[k], the collector (C) is electrically connected to the power supply line LH, which is set to the power supply potential VHV, and the emitter (E) is electrically connected to the wiring LC[k] used to supply the drive signal Com[k].

[0151] In the bipolar transistor Tr2[k], the base (B) is electrically connected to the output terminal Tn2[k], and a base supply signal QB2[k] is supplied from the output terminal Tn2[k]. Additionally, in the bipolar transistor Tr2[k], the collector (C) is electrically connected to ground, and the emitter (E) is electrically connected to the wiring LC[k] used to supply the drive signal Com[k].

[0152] Electrolytic capacitor CC[k] is a capacitor used to supply current to transistor Tr1[k]. Specifically, in electrolytic capacitor CC[k], one of its two electrodes is electrically connected to the power supply line LH and the collector of bipolar transistor Tr1[k], and the other electrode is electrically connected to ground.

[0153] As described above, according to this modification, multiple transistor pairs 52[k] can be driven by a single analog-to-digital converter circuit 51B. Furthermore, in this modification, the analog-to-digital converter circuit 51B is cooled by the analog-to-digital converter circuit cooling mechanism CL2. Therefore, in this modification, even if the amount of base current supplied from the analog-to-digital converter circuit 51B to the multiple transistor pairs 52[k] increases, the high temperature of the analog-to-digital converter circuit 51B can be suppressed.

[0154] B.4. Variation Example 4

[0155] In the above embodiments and variations 1 to 3, examples illustrate how fan FN1 maintains its operation regardless of the temperature of the transistor pair 52 provided on the transistor substrate 501, and fan FN2 maintains its operation regardless of the temperature of the analog-to-digital converter circuit 51 provided on the analog-to-digital converter circuit substrate 502. However, the present invention is not limited to this approach. Fan FN1 may also be driven based on the temperature of the transistor pair 52 provided on the transistor substrate 501. Similarly, fan FN2 may also be driven based on the temperature of the analog-to-digital converter circuit 51 provided on the analog-to-digital converter circuit substrate 502.

[0156] Figure 13 This is a functional block diagram illustrating an example of the structure of the inkjet printer 1C involved in this variation.

[0157] like Figure 13 As shown, the inkjet printer 1C is configured similarly to the inkjet printer 1 according to the embodiment, except that it has the aspects of replacing the control unit 2C and replacing the drive signal generation unit 5C. It should be noted that in this modified example, the structure including the control unit 2C and the drive signal generation unit 5C is referred to as the drive control unit 8C. In this modified example, the drive control unit 8C is an example of a "drive device".

[0158] The drive signal generation unit 5C differs from the drive signal generation unit 5 according to the embodiment in that it includes temperature sensors TS1 and TS2. For example, temperature sensor TS1 is configured to include a thermistor provided on transistor substrate 501 and output temperature information DT1, which represents temperature TT1 based on the temperature of transistor pair 52. For example, temperature sensor TS2 is configured to include a thermistor provided on analog conversion circuit substrate 502 and output temperature information DT2, which represents temperature TT2 based on the temperature of analog conversion circuit 51.

[0159] The control unit 2C differs from the control unit 2 in the embodiment in that it has a control circuit 21C instead of a control circuit 21.

[0160] The control circuit 21C generates a fan control signal SF1 that specifies whether to drive or stop the fan FN1 based on the temperature TT1 represented by the temperature information DT1. Thus, the control circuit 21C operates the fan FN1 based on the temperature TT1. More specifically, in this modified example, the control circuit 21C generates the fan control signal SF1 to operate the fan FN1 when the temperature TT1 is above a predetermined temperature, and generates the fan control signal SF1 to stop the fan FN1 when the temperature TT1 is below the predetermined temperature. However, the present invention is not limited to this method. For example, the control circuit 21C may generate the fan control signal SF1 to operate the fan FN1 when the difference between the temperature TT1 and the ambient temperature of the inkjet printer 1C is above a predetermined threshold, and generate the fan control signal SF1 to stop the fan FN1 when the difference between the temperature TT1 and the ambient temperature of the inkjet printer 1C is below the predetermined threshold. In this case, the inkjet printer 1C may also be equipped with a temperature sensor (not shown) that measures the ambient temperature of the inkjet printer 1C.

[0161] The control circuit 21C generates a fan control signal SF2 that specifies whether to drive or stop the fan FN2 based on the temperature TT2 represented by the temperature information DT2. Thus, the control circuit 21C operates the fan FN2 based on the temperature TT2. More specifically, in this modified example, the control circuit 21C generates the fan control signal SF2 to operate the fan FN2 when the temperature TT2 is above a predetermined temperature, and generates the fan control signal SF2 to stop the fan FN2 when the temperature TT2 is below the predetermined temperature. However, the present invention is not limited to this method. For example, the control circuit 21C may generate the fan control signal SF2 to operate the fan FN2 when the difference between the temperature TT2 and the ambient temperature of the inkjet printer 1C is above a predetermined threshold, and generate the fan control signal SF2 to stop the fan FN2 when the difference between the temperature TT2 and the ambient temperature of the inkjet printer 1C is less than the predetermined threshold. In this case, the inkjet printer 1C may also be equipped with a temperature sensor (not shown) that measures the ambient temperature of the inkjet printer 1C.

[0162] As described above, according to this modified example, since fan FN1 can be operated based on the temperature of transistor pair 52 and fan FN2 can be operated based on the temperature of analog conversion circuit 51, the power consumption involved in the operation of fan FN1 and fan FN2 can be reduced compared to the method of always operating fan FN1 and fan FN2.

[0163] B.5. Variation Example 5

[0164] In the above embodiments and variations 1 to 4, examples illustrate the case where the transistor substrate 501 and the analog conversion circuit substrate 502 are fixed to the substrate connector CN1 via the substrate, but the present invention is not limited to this method. The transistor substrate 501 and the analog conversion circuit substrate 502 can also be fixed by a pin header. Here, a pin header refers to a connector having an insertion pin component and a pin socket. The insertion pin component has: a plurality of insertion pins formed of metal; and a retaining portion that holds the plurality of insertion pins in an insulated state from each other. The pin socket has a plurality of insertion holes corresponding to the plurality of insertion pins.

[0165] In this modified example, it is envisioned that the insertion pin component of the pin header is fixed to surface PL11 of the transistor substrate 501, and the pin socket of the pin header is fixed to surface PL22 of the analog-to-digital converter circuit substrate 502. The pin header fixes the transistor substrate 501 and the analog-to-digital converter circuit substrate 502 by engaging the insertion pin component and the pin socket, and transmits signals between the transistor substrate 501 and the analog-to-digital converter circuit substrate 502.

[0166] B.6. Variation Example 6

[0167] In the above embodiments and variations 1 to 5, examples illustrate the case where the transistor cooling mechanism CL1 includes a heat sink HS1 and a fan FN1, but the present invention is not limited to this configuration. The transistor cooling mechanism CL1 may also include a water-cooled cooling device.

[0168] Furthermore, in the above embodiments and variations 1 to 5, examples illustrate the case where the analog conversion circuit cooling mechanism CL2 includes a heat sink HS2 and a fan FN2, but the present invention is not limited to this configuration. The analog conversion circuit cooling mechanism CL2 may also include a water-cooled cooling device.

[0169] B.7. Variation 7

[0170] In the above embodiments and variations 1 to 6, the example control unit 2 was described as being mounted on the carriage 110 as a drive control unit 8, but the present invention is not limited to this arrangement. The control unit 2 may also be provided separately from the drive control unit 8. In this case, the control unit 2 may also be provided outside the carriage 110.

[0171] B.8. Variation Example 8

[0172] In the above embodiments and variations 1 to 7, the drive control unit 8 is illustrated as being mounted on the carriage 110, but the present invention is not limited to this arrangement. The drive control unit 8 may also be located outside the carriage 110.

[0173] B.9. Variation Example 9

[0174] In the above embodiments and variations 1 to 8, the inkjet printer 1 is envisioned as a serial printer, but the present invention is not limited to this. The inkjet printer 1 can also be a so-called line printer in which a plurality of nozzles N in the liquid ejection unit 3 are configured to extend wider than the width of the recording paper PP.

[0175] C. Appendix

[0176] The following appendix provides an explanation of the manner in which the foregoing description is applied. It should be noted that, for ease of understanding of the various manners, reference numerals to the accompanying drawings are appropriately enclosed in parentheses in the appendix, but this is not intended to limit the invention to the illustrative manner.

[0177] C.1. Appendix 1

[0178] The inkjet printer 1 mentioned in Appendix 1 will be described below.

[0179] Appendix 1-1

[0180] Appendix 1-1 describes an inkjet printer 1 characterized by comprising: a liquid ejection unit 3, which is driven by a drive signal Com to eject ink; an analog-to-digital converter 51, which converts a digital waveform specification signal dCom, which specifies the waveform of the drive signal Com, into an analog waveform specification signal QB, which specifies the waveform of the drive signal Com; a transistor pair 52, comprising two bipolar transistors Tr that generate the drive signal Com based on the waveform specification signal QB; a transistor cooling mechanism CL1, which cools the transistor pair 52; and an analog-to-digital converter cooling mechanism CL2, which cools the analog-to-digital converter 51.

[0181] It should be noted that in Appendix 1-1, the drive signal Com is an example of the "first drive signal", and the transistor pair 52 is an example of the "first transistor pair".

[0182] According to Appendix 1-1, since the analog-to-digital converter cooling mechanism CL2 is provided separately from the transistor cooling mechanism CL1, the overheating of the analog-to-digital converter 51 can be suppressed compared to the method of cooling both the analog-to-digital converter 51 and the transistor pair 52 by a single cooling mechanism. Therefore, according to Appendix 1-1, the instability of the operation of the analog-to-digital converter 51 caused by the overheating of the analog-to-digital converter 51 can be suppressed.

[0183] Appendix 1-2

[0184] The inkjet printer 1 described in Appendix 1-2 is characterized in that, in the inkjet printer 1 described in Appendix 1-1, the output terminal Tn1 of the analog conversion circuit 51 is electrically connected to the base 62B of the bipolar transistor Tr.

[0185] According to Appendix 1-2, even when the drive signal Com is a large amplitude signal and the base current supplied from the analog conversion circuit 51 to the transistor pair 52 is a large current, the high temperature of the analog conversion circuit 51 can be suppressed, thus suppressing the instability of the operation of the analog conversion circuit 51 caused by the high temperature of the analog conversion circuit 51.

[0186] Appendix 1-3

[0187] The inkjet printer 1 described in Appendix 1-3 is characterized in that, in the inkjet printer 1 described in Appendix 1-1 or Appendix 1-2, the analog conversion circuit cooling mechanism CL2 includes: a heat sink HS2 connected to the analog conversion circuit 51 or an analog conversion circuit board 502 on which the analog conversion circuit 51 is mounted; and a fan FN2 that operates based on the temperature of the analog conversion circuit 51.

[0188] According to Appendix 1-3, the high temperature of the analog conversion circuit 51 can be suppressed.

[0189] Appendix 1-4

[0190] The inkjet printer 1 described in Appendices 1-4 is characterized in that, in the inkjet printer 1 described in Appendices 1-1 to 1-3, it includes: a transistor substrate 501 having transistor pairs 52; an analog-to-digital converter circuit substrate 502 having an analog-to-digital converter circuit 51; a control circuit 21 for generating a waveform specification signal dCom; and a control substrate 200 having the control circuit 21, wherein the control substrate 200 is configured to be separate from the analog-to-digital converter circuit substrate 502.

[0191] According to Appendices 1-4, compared with the method where the control board 200 and the analog conversion circuit board 502 are the same board, it is possible to suppress the overheating of the control board 200.

[0192] Appendix 1-5

[0193] The inkjet printer 1 described in Appendices 1-5 is characterized in that, in the inkjet printer 1 described in Appendices 1-4, the analog conversion circuit board 502 and the control board 200 are connected via a board-to-board connector CN2.

[0194] According to Appendices 1-5, even when the analog conversion circuit board 502 and the control board 200 are mounted on the carriage 110 that moves within the inkjet printer 1, and the analog conversion circuit board 502 and the control board 200 vibrate, the analog conversion circuit board 502 and the control board 200 can be kept stably connected.

[0195] Appendix 1-6

[0196] The inkjet printer 1 described in Appendices 1-6 is characterized in that, in the inkjet printer 1 described in Appendices 1-4 or 1-5, the analog conversion circuit board 502 is configured to be separate from the transistor board 501.

[0197] According to Appendices 1-6, compared to a configuration where the analog-to-digital converter circuit 51 and the transistor pair 52 are mounted on the same substrate, the transfer of heat from the transistor pair 52 to the analog-to-digital converter circuit 51 can be suppressed. Therefore, according to Appendices 1-6, the overheating of the analog-to-digital converter circuit 51 and the instability of its operation can be suppressed.

[0198] Appendix 1-7

[0199] The inkjet printer 1 described in Appendices 1-7 is characterized in that, in the inkjet printer 1 described in Appendices 1-4 to 1-6, the transistor substrate 501 and the analog conversion circuit substrate 502 are connected by a substrate-to-substrate connector CN1.

[0200] According to Appendices 1-7, even when the transistor substrate 501 and the analog conversion circuit substrate 502 are mounted on the carriage 110 that moves within the inkjet printer 1, or when the transistor substrate 501 and the analog conversion circuit substrate 502 vibrate, the transistor substrate 501 and the analog conversion circuit substrate 502 can be kept stably connected.

[0201] Appendix 1-8

[0202] The inkjet printer 1 described in Appendices 1-8 is characterized in that, in the inkjet printer 1 described in Appendices 1-4 to 1-6, the transistor substrate 501 and the analog conversion circuit substrate 502 are connected by a pin header.

[0203] According to Appendices 1-8, even when the transistor substrate 501 and the analog conversion circuit substrate 502 are mounted on the carriage 110 that moves within the inkjet printer 1, or when the transistor substrate 501 and the analog conversion circuit substrate 502 vibrate, the transistor substrate 501 and the analog conversion circuit substrate 502 can be kept stably connected.

[0204] Appendix 1-9

[0205] The inkjet printer 1 described in Appendices 1-9 is characterized in that the inkjet printer 1 described in Appendices 1-1 to 1-8 includes a transistor substrate 501, which is provided with transistor pairs 52, and bipolar transistors Tr are provided on the transistor substrate 501 in such a way that the surface 600 with the largest area among the multiple surfaces of the bipolar transistor Tr is connected to the transistor substrate 501.

[0206] According to Appendices 1-9, since the surface 600 with the largest area among the multiple surfaces of the bipolar transistor Tr is connected to the transistor substrate 501, the heat generated in the bipolar transistor Tr can be dissipated more efficiently compared to, for example, the surface with the smallest area among the multiple surfaces of the bipolar transistor Tr being connected to the transistor substrate 501, or the multiple surfaces of the bipolar transistor Tr not being connected to the transistor substrate 501.

[0207] Appendix 1-10

[0208] The inkjet printer 1 described in Appendix 1-10 is characterized by comprising: a liquid ejection unit 3, which ejects ink driven by drive signal Com[1] and drive signal Com[2]; an analog conversion circuit 51B, which converts a waveform specification signal dCom[1] that specifies the waveform of drive signal Com[1] into an analog waveform specification signal QB[1] that specifies the waveform of drive signal Com[1], and converts a waveform specification signal dCom[2] that specifies the waveform of drive signal Com[2] into an analog waveform specification signal QB[2] that specifies the waveform of drive signal Com[2]; a transistor pair 52[1], comprising two bipolar transistors Tr that generate drive signal Com[1] based on waveform specification signal QB[1]; a transistor pair 52[2], comprising two bipolar transistors Tr that generate drive signal Com[2] based on waveform specification signal QB[2]; a transistor cooling mechanism CL1, which cools transistor pair 52[1] and transistor pair 52[2]; and an analog conversion circuit cooling mechanism CL2, which cools analog conversion circuit 51B.

[0209] It should be noted that in Appendix 1-10, the driving signal Com[1] is an example of the "first driving signal", the driving signal Com[2] is an example of the "second driving signal", the transistor pair 52[1] is an example of the "first transistor pair", the transistor pair 52[2] is an example of the "second transistor pair", the waveform designation signal dCom[1] is an example of the "first waveform signal", the waveform designation signal QB[1] is an example of the "second waveform signal", the waveform designation signal dCom[2] is an example of the "third waveform signal", and the waveform designation signal QB[2] is an example of the "fourth waveform signal".

[0210] According to Appendix 1-10, even when the base current supplied from analog converter circuit 51B to transistor pair 52[1] and transistor pair 52[2] is a large current, the high temperature of analog converter circuit 51B can be suppressed, thus suppressing the instability of analog converter circuit 51B caused by the high temperature of analog converter circuit 51B.

[0211] It should be noted that in Appendix 1-10, the waveform specification signal dCom[1] and the waveform specification signal dCom[2] can also be the same signal (waveform specification signal dCom).

[0212] Appendix 1-11

[0213] The inkjet printer 1 described in Appendices 1-11 is characterized in that, in the inkjet printer 1 described in Appendices 1-1 to 1-10, the transistor cooling mechanism CL1 has a heat sink HS1, which is connected to the transistor substrate 501 on which the transistor pair 52 is mounted, and is formed of aluminum; the analog conversion circuit cooling mechanism CL2 has a heat sink HS2, which is connected to the analog conversion circuit 51 or the analog conversion circuit substrate 502 on which the analog conversion circuit 51 is mounted, and is formed of copper.

[0214] According to Appendix 1-11, it is possible to suppress the high temperature of the analog-to-digital converter circuit 51 and suppress the instability of the operation of the analog-to-digital converter circuit 51.

[0215] Appendix 1-12

[0216] The inkjet printer 1 described in Appendix 1-12 is characterized in that, in the inkjet printer 1 described in Appendix 1-1 to Appendix 1-11, the transistor cooling mechanism CL1 is equipped with a water-cooled cooling device.

[0217] According to Appendix 1-12, it is possible to suppress the high temperature of transistor 52.

[0218] C.2. Appendix 2

[0219] The inkjet printer 1 mentioned in Appendix 2 will be described below.

[0220] Appendix 2-1

[0221] Appendix 2-1 describes an inkjet printer 1 characterized by comprising: a liquid ejection unit 3, which is driven by a drive signal Com to eject ink; a transistor substrate 501; a transistor pair 52 disposed on the transistor substrate 501 and including two bipolar transistors Tr that generate the drive signal Com; an analog-to-digital converter circuit substrate 502; and an analog-to-digital converter circuit 51 disposed on the analog-to-digital converter circuit substrate 502, which converts a digital waveform specification signal dCom that specifies the waveform of the drive signal Com into an analog waveform specification signal QB that specifies the waveform of the drive signal Com, wherein the transistor pair 52 generates the drive signal Com based on the waveform specification signal QB, and the analog-to-digital converter circuit substrate 502 is configured to be separate from the transistor substrate 501.

[0222] According to Appendix 2-1, since the transistor substrate 501 with transistor pair 52 and the analog conversion circuit substrate 502 with analog conversion circuit 51 are provided separately, compared with the method where analog conversion circuit 51 and transistor pair 52 are provided on the same substrate, the transfer of heat from transistor pair 52 to analog conversion circuit 51 can be suppressed. Therefore, according to Appendix 2-1, the high temperature of analog conversion circuit 51 during the generation of drive signal Com can be suppressed, and the instability of analog conversion circuit 51 operation caused by high temperature of analog conversion circuit 51 can be suppressed.

[0223] Appendix 2-2

[0224] The inkjet printer 1 described in Appendix 2-2 is characterized in that, in the inkjet printer 1 described in Appendix 2-1, it has a transistor cooling mechanism CL1, which cools the transistor pair 52.

[0225] According to Appendix 2-2, since the high temperature of transistor pair 52 can be suppressed, the high temperature of analog conversion circuit 51 caused by the heat in transistor pair 52 being transferred to analog conversion circuit 51 can also be suppressed.

[0226] Appendix 2-3

[0227] The inkjet printer 1 described in Appendix 2-3 is characterized in that, in the inkjet printer 1 described in Appendix 2-1 or Appendix 2-2, the transistor substrate 501 has a surface PL11 and a surface PL12 on the side opposite to the surface PL11, an electronic component including a pair of transistors 52 is disposed on the surface PL11, and a transistor cooling mechanism CL1 is disposed on the surface PL12.

[0228] It should be noted that in Appendix 2-3, face PL11 is an example of the "first face" and face PL12 is an example of the "second face".

[0229] According to Appendix 2-3, since the high temperature of transistor pair 52 can be suppressed, the high temperature of analog conversion circuit 51 caused by the heat in transistor pair 52 being transferred to analog conversion circuit 51 can also be suppressed.

[0230] Appendix 2-4

[0231] The inkjet printer 1 described in Appendix 2-4 is characterized in that, in the inkjet printer 1 described in Appendix 2-2 or Appendix 2-3, the transistor cooling mechanism CL1 includes: a heat sink HS1 connected to the substrate 75 of the transistor substrate 501; and a fan FN1 that operates based on the temperature of the transistor 52.

[0232] According to Appendix 2-4, since the high temperature of transistor pair 52 can be suppressed, the high temperature of analog conversion circuit 51 caused by the heat in transistor pair 52 being transferred to analog conversion circuit 51 can also be suppressed.

[0233] Appendix 2-5

[0234] The inkjet printer 1 described in Appendix 2-5 is characterized in that, in the inkjet printer 1 described in Appendix 2-1 to Appendix 2-3, an electrolytic capacitor CC is provided on the analog conversion circuit board 502 to supply current to the transistor pair 52.

[0235] According to Appendix 2-5, compared with the arrangement where the electrolytic capacitor CC and the transistor pair 52 are disposed on the same substrate, the heat transfer from the transistor pair 52 to the electrolytic capacitor CC can be suppressed. Therefore, according to Appendix 2-5, compared with the arrangement where the electrolytic capacitor CC and the transistor pair 52 are disposed on the same substrate, the heat-induced degradation of the electrolytic capacitor CC can be suppressed, and the lifespan of the electrolytic capacitor CC can be extended.

[0236] Appendix 2-6

[0237] The inkjet printer 1 described in Appendices 2-6 is characterized in that, in the inkjet printer 1 described in Appendices 2-1 to 2-5, the transistor substrate 501 and the analog conversion circuit substrate 502 are connected by a substrate-to-substrate connector CN1.

[0238] According to Appendix 2-6, even when the transistor substrate 501 and the analog conversion circuit substrate 502 are mounted on the carriage 110 that moves within the inkjet printer 1, or when the transistor substrate 501 and the analog conversion circuit substrate 502 vibrate, the transistor substrate 501 and the analog conversion circuit substrate 502 can be stably connected.

[0239] Appendix 2-7

[0240] The inkjet printer 1 mentioned in Appendices 2-7 is characterized in that the transistor substrate 501 and the analog conversion circuit substrate 502 are connected by a pin header.

[0241] According to Appendix 2-7, even when the transistor substrate 501 and the analog conversion circuit substrate 502 are mounted on the carriage 110 that moves within the inkjet printer 1, and the transistor substrate 501 and the analog conversion circuit substrate 502 vibrate, the transistor substrate 501 and the analog conversion circuit substrate 502 can be kept stably connected.

[0242] Appendix 2-8

[0243] The inkjet printer 1 described in Appendices 2-8 is characterized in that, in the inkjet printer 1 described in Appendices 2-1 to 2-7, a connector (substrate-to-substrate connector CN1 or pin header) is provided to connect the transistor substrate 501 and the analog conversion circuit substrate 502, and the connector is disposed in the central region AM of the transistor substrate 501.

[0244] It should be noted that in Appendix 2-8, the Central Region AM is an example of the "Central Department".

[0245] According to Appendix 2-8, even when the transistor substrate 501 and the analog conversion circuit substrate 502 are mounted on the carriage 110 that moves within the inkjet printer 1, or when the transistor substrate 501 and the analog conversion circuit substrate 502 vibrate, the transistor substrate 501 and the analog conversion circuit substrate 502 can be kept stably connected.

[0246] Appendix 2-9

[0247] The inkjet printer 1 described in Appendix 2-9 is characterized in that, in the inkjet printer 1 described in Appendix 2-1 to Appendix 2-8, the transistor substrate 501 has: long sides LY1 and LY2 facing each other, and short sides LX1 and LX2 facing each other, and a plurality of transistor pairs 52 are provided on the transistor substrate 501, and the plurality of bipolar transistors Tr of the plurality of transistor pairs 52 are arranged along the long sides LY1 and LY2.

[0248] According to Appendix 2-9, heat generated in multiple bipolar transistors Tr can be efficiently dissipated from the long side LY1 and the long side LY2.

[0249] Appendix 2-10

[0250] The inkjet printer 1 described in Appendix 2-10 is characterized in that, in the inkjet printer 1 described in Appendices 2-1 to 2-9, the bipolar transistor Tr is disposed on the transistor substrate 501 in such a way that the surface 600 with the largest area among the plurality of surfaces of the bipolar transistor Tr is connected to the transistor substrate 501.

[0251] According to Appendix 2-10, since the surface 600 with the largest area among the multiple surfaces of the bipolar transistor Tr is connected to the transistor substrate 501, the heat generated in the bipolar transistor Tr can be dissipated more efficiently compared to, for example, the surface with the smallest area among the multiple surfaces of the bipolar transistor Tr being connected to the transistor substrate 501, or the multiple surfaces of the bipolar transistor Tr not being connected to the transistor substrate 501.

[0252] Appendix 2-11

[0253] The inkjet printer 1 described in Appendix 2-11 is characterized in that, in the inkjet printer 1 described in Appendices 2-1 to 2-10, the transistor substrate 501 has a surface PL11 and a surface PL12 on the side opposite to the surface PL11. A bipolar transistor Tr is disposed on the surface PL11, and a transistor cooling mechanism CL1 for cooling the bipolar transistor Tr is disposed on the surface PL12. The bipolar transistor Tr is fixed to the transistor cooling mechanism CL1 by a screw 65 passing through the transistor substrate 501.

[0254] According to Appendix 2-11, since the heat generated from the bipolar transistor Tr can be dissipated to the transistor cooling mechanism CL1 via screw 65, the high temperature of the bipolar transistor Tr can be suppressed.

[0255] C.3. Appendix 3

[0256] The inkjet printer 1 mentioned in Appendix 3 will be described below.

[0257] Appendix 3-1

[0258] Appendix 3-1 describes an inkjet printer 1 characterized by comprising: a liquid ejection unit 3, which is driven by a drive signal Com to eject ink; a metal transistor substrate 501; and a transistor pair 52 disposed on the transistor substrate 501, including two bipolar transistors Tr that generate the drive signal Com.

[0259] According to Appendix 3-1, since the transistor pair 52 is disposed on a metal transistor substrate 501, heat generated in the transistor pair 52 can be dissipated more efficiently compared to the case where the transistor pair 52 is disposed on a resin substrate. Therefore, according to Appendix 3-1, high temperature of the transistor pair 52 can be suppressed.

[0260] Appendix 3-2

[0261] The inkjet printer 1 described in Appendix 3-2 is characterized in that, in the inkjet printer 1 described in Appendix 3-1, it has a carriage 110 for moving the liquid ejection unit 3, and the transistor substrate 501 has a substrate 75 formed of aluminum and is mounted on the carriage 110.

[0262] According to Appendix 3-2, since an aluminum substrate with an aluminum base is used as the transistor substrate 501, for example, compared with a substrate with a copper base, the transistor substrate 501 can be made lighter. Therefore, according to Appendix 3-2, the load on the carriage transport motor 91 that moves the carriage 110 carrying the transistor substrate 501 can be reduced, and the lifespan of the carriage transport motor 91 can be extended, as well as the power consumption involved in driving the carriage transport motor 91 can be reduced.

[0263] Appendix 3-3

[0264] The inkjet printer 1 described in Appendix 3-3 is characterized in that, in the inkjet printer 1 described in Appendix 3-2, it includes a heat sink HS1, which is connected to the substrate 75 of the transistor substrate 501 and is formed of aluminum.

[0265] According to Appendix 3-3, since the heat generated from transistor pair 52 can be dissipated from heat sink HS1, the high temperature of transistor pair 52 can be suppressed.

[0266] Furthermore, according to Appendix 3-3, since the radiator HS1 is made of aluminum, its weight can be reduced compared to the case where the radiator HS1 is made of copper. Therefore, according to Appendix 3-3, the lifespan of the carriage transport motor 91 can be extended, and the power consumption involved in driving the carriage transport motor 91 can be reduced.

[0267] Furthermore, according to Appendix 3-3, since an aluminum heat sink HS1 is connected to the transistor substrate 501 with an aluminum substrate 75, the possibility of corrosion at the boundary between the transistor substrate 501 and the heat sink HS1 can be reduced compared to, for example, using a copper substrate as the transistor substrate 501 and connecting the aluminum heat sink HS1 to the transistor substrate 501. Therefore, according to Appendix 3-3, it is not necessary to sandwich a heat sink between the transistor substrate 501 and the heat sink HS1; grease 64 can be sandwiched between the transistor substrate 501 and the heat sink HS1. Thus, according to Appendix 3-3, compared to using a copper substrate as the transistor substrate 501, it is possible to achieve miniaturization of the drive signal generation unit 5 including the transistor substrate 501 and the heat sink HS1, cost reduction of the drive signal generation unit 5, and reduction of the number of components in the drive signal generation unit 5.

[0268] Appendix 3-4

[0269] The inkjet printer 1 described in Appendix 3-4 is characterized in that, in the inkjet printer 1 described in Appendix 3-1 to Appendix 3-3, a fan FN1 is provided, which operates based on the temperature of 52 by a transistor.

[0270] According to Appendix 3-4, since the heat generated from transistor pair 52 can be dissipated by fan FN1, the high temperature of transistor pair 52 can be suppressed.

[0271] Appendix 3-5

[0272] The inkjet printer 1 described in Appendix 3-5 is characterized in that, in the inkjet printer 1 described in Appendix 3-1 to Appendix 3-4, it includes: an analog conversion circuit board 502; and an analog conversion circuit 51 disposed on the analog conversion circuit board 502, which converts a digital waveform specification signal dCom that specifies the waveform of the drive signal Com into an analog waveform specification signal QB that specifies the waveform of the drive signal Com, and a transistor pair 52 generates the drive signal Com based on the waveform specification signal QB, and the analog conversion circuit board 502 is configured to be separate from the transistor board 501.

[0273] According to Appendix 3-5, since the analog-to-digital converter circuit substrate 502 is configured to be separate from the transistor substrate 501, compared to the configuration where the analog-to-digital converter circuit 51 and the transistor pair 52 are disposed on the same substrate, the transfer of heat from the transistor pair 52 to the analog-to-digital converter circuit 51 can be suppressed. Therefore, according to Appendix 3-5, the overheating of the analog-to-digital converter circuit 51 can be suppressed, as can the instability of the operation of the analog-to-digital converter circuit 51.

[0274] Appendix 3-6

[0275] The inkjet printer 1 described in Appendix 3-6 is characterized in that, in the inkjet printer 1 described in Appendix 3-5, it includes: a transistor cooling mechanism CL1 for cooling the transistor pair 52, and an analog conversion circuit cooling mechanism CL2 for cooling the analog conversion circuit 51.

[0276] According to Appendix 3-6, since the analog-to-digital converter cooling mechanism CL2 is provided separately from the transistor cooling mechanism CL1, the overheating of the analog-to-digital converter 51 can be suppressed compared to the method of cooling both the analog-to-digital converter 51 and the transistor pair 52 by a single cooling mechanism. Therefore, according to Appendix 3-6, the instability of the analog-to-digital converter 51 caused by its overheating can be suppressed.

[0277] Appendix 3-7

[0278] The inkjet printer 1 described in Appendix 3-7 is characterized in that, in the inkjet printer 1 described in Appendix 3-1, the transistor substrate 501 has a substrate 75 formed of copper.

[0279] According to Appendix 3-7, since the transistor pair 52 is disposed on a transistor substrate 501 having a copper substrate, the heat generated in the transistor pair 52 can be effectively dissipated compared to the method of disposing the transistor pair 52 on a resin substrate.

[0280] Appendix 3-8

[0281] The inkjet printer 1 described in Appendices 3-8 is characterized in that, in the inkjet printer 1 described in Appendices 3-1 to 3-7, the bipolar transistor Tr is disposed on the transistor substrate 501 in such a way that the surface 600 with the largest area among the plurality of surfaces of the bipolar transistor Tr is connected to the transistor substrate 501.

[0282] According to Appendix 3-8, since the surface 600 with the largest area among the multiple surfaces of the bipolar transistor Tr is connected to the transistor substrate 501, the heat generated in the bipolar transistor Tr can be dissipated more efficiently compared to, for example, the surface with the smallest area among the multiple surfaces of the bipolar transistor Tr being connected to the transistor substrate 501, or the multiple surfaces of the bipolar transistor Tr not being connected to the transistor substrate 501.

Claims

1. A liquid ejection device, characterized in that, have: The liquid ejector head is driven by a drive signal to eject liquid. First substrate; A pair of transistors is disposed on the first substrate and includes two bipolar transistors that generate the drive signal; Second substrate; as well as An analog-to-digital converter circuit, disposed on the second substrate, converts a first waveform signal, which represents a specified digital representation of the waveform of the driving signal, into a second waveform signal, which represents a specified analog representation of the waveform of the driving signal. The transistors generate the drive signal based on the second waveform signal. The second substrate is configured to be separate from the first substrate.

2. The liquid ejection device according to claim 1, characterized in that, The liquid ejection device includes a first cooling mechanism that cools the transistor pair.

3. The liquid ejection device according to claim 2, characterized in that, The first substrate has a first surface and a second surface opposite to the first surface. An electronic component including the transistor pair is disposed on the first surface. The first cooling mechanism is disposed on the second side.

4. The liquid ejection device according to claim 2, characterized in that, The first cooling mechanism includes: A first heat sink is connected to the substrate of the first substrate; and The first fan operates based on the temperature of the transistor pair.

5. The liquid ejection device according to claim 1, characterized in that, An electrolytic capacitor is provided on the second substrate to supply current to the transistor pair.

6. The liquid ejection device according to claim 1, characterized in that, The first substrate and the second substrate are connected via a substrate-to-substrate connector.

7. The liquid ejection device according to claim 1, characterized in that, The first substrate and the second substrate are connected by pin headers.

8. The liquid ejection device according to claim 1, characterized in that, The liquid ejection device includes a connector for connecting the first substrate and the second substrate. The connector is disposed in the center of the first substrate.

9. The liquid ejection device according to claim 1, characterized in that, The first substrate has: two long sides opposite each other, and two short sides opposite each other. A plurality of transistor pairs are provided on the first substrate. The plurality of bipolar transistors in the plurality of transistor pairs are configured to be arranged along the long side of the first substrate.

10. The liquid ejection device according to claim 1, characterized in that, The bipolar transistor is disposed on the first substrate such that the largest of the plurality of faces of the bipolar transistor is connected to the first substrate.

11. The liquid ejection device according to claim 1, characterized in that, The first substrate has a first surface and a second surface opposite to the first surface. The bipolar transistor is disposed on the first surface. A first cooling mechanism is disposed on the second surface, and the first cooling mechanism cools the bipolar transistor. The bipolar transistor is fixed to the first cooling mechanism by a screw that passes through the first substrate.

12. A driving device, characterized in that, The driving device supplies a driving signal to the liquid nozzle, and the liquid nozzle is driven by the driving signal to spray liquid. The driving device comprises: First substrate; A pair of transistors is disposed on the first substrate and includes two bipolar transistors that generate the drive signal; Second substrate; as well as An analog-to-digital converter circuit, disposed on the second substrate, converts a first waveform signal, which represents a specified digital representation of the waveform of the driving signal, into a second waveform signal, which represents a specified analog representation of the waveform of the driving signal. The transistors generate the drive signal based on the second waveform signal. The second substrate is configured to be separate from the first substrate.

13. The driving device according to claim 12, characterized in that, The drive device includes a first cooling mechanism that cools the transistor pair.

14. The driving device according to claim 13, characterized in that, The first substrate has a first surface and a second surface opposite to the first surface. An electronic component including the transistor pair is disposed on the first surface. The first cooling mechanism is disposed on the second side.

15. The driving device according to claim 13, characterized in that, The first cooling mechanism includes: A first heat sink is connected to the substrate of the first substrate; and The first fan operates based on the temperature of the transistor pair.

16. The driving device according to claim 12, characterized in that, An electrolytic capacitor is provided on the second substrate to supply current to the transistor pair.

17. The driving device according to claim 12, characterized in that, The first substrate and the second substrate are connected via a substrate-to-substrate connector.

18. The driving device according to claim 12, characterized in that, The first substrate and the second substrate are connected by pin headers.

19. The driving device according to claim 12, characterized in that, The driving device includes a connector for connecting the first substrate and the second substrate. The connector is disposed in the center of the first substrate.

20. The driving device according to claim 12, characterized in that, The first substrate has two long sides facing each other and two short sides facing each other. A plurality of transistor pairs are provided on the first substrate. The plurality of bipolar transistors in the plurality of transistor pairs are configured to be arranged along the long side of the first substrate.

21. The driving device according to claim 12, characterized in that, The bipolar transistor is disposed on the first substrate such that the largest of the plurality of faces of the bipolar transistor is connected to the first substrate.

22. The driving device according to claim 12, characterized in that, The first substrate has a first surface and a second surface opposite to the first surface. The bipolar transistor is disposed on the first surface. A first cooling mechanism is disposed on the second surface, which cools the bipolar transistor. The bipolar transistor is fixed to the first cooling mechanism by a screw that passes through the first substrate.

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