Liquid ejecting apparatus and driving apparatus

Abstract

The invention relates to a liquid ejecting apparatus and a driving apparatus. A transistor pair that generates a drive signal is prevented from increasing in temperature. A liquid ejecting apparatus includes: a liquid ejecting head that is driven by a drive signal to eject a liquid; a first substrate made of metal; and a transistor pair disposed on the first substrate and including two bipolar transistors that generate the driving signal.

Description

Technical Field

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

[0002] A liquid ejection device is known to include a liquid ejection head and a drive signal generation circuit. The liquid ejection head ejects liquid such as ink in response to a drive signal, and the drive signal generation circuit supplies a drive signal to the liquid ejection head. For example, Patent Document 1 discloses a liquid ejection device provided with a drive signal generation circuit, which includes a pair of transistors for generating a drive signal.

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

[0004] The drive signal for the liquid ejector head is a high-amplitude signal, and the transistors generate heat when generating the drive signal. Therefore, when the drive signal generation circuit generates the drive signal, the temperature of the drive signal generation circuit may rise, leading to unstable operation of the drive signal generation circuit. Summary of the Invention

[0005] To solve the above technical problems, the liquid ejection device of the present invention is characterized by comprising: a liquid ejection head that ejects liquid by being driven by a drive signal; a first metal substrate; and a pair of transistors disposed on the first substrate, including two bipolar transistors that generate the drive signal.

[0006] Furthermore, the driving device according to the present invention is characterized in that the driving device supplies the driving signal to a liquid ejector head that is driven by the driving signal to eject liquid, and the driving device comprises: a first metal substrate; and a pair of transistors disposed on the first substrate, including two bipolar transistors that generate the driving signal. Attached Figure Description

[0007] Figure 1 This is a block diagram illustrating an example of the configuration 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 schematic 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 configuration of the liquid ejection unit 3.

[0011] Figure 5This 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 showing an example of the configuration 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 structure 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 configuration 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 configuration of an inkjet printer 1C according to Modification 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, the dimensions and scales of the various parts in the drawings differ appropriately from the actual dimensions. Furthermore, since the embodiments described below are preferred examples of the present invention, various technically preferred limitations are applied, but the scope of the present invention is not limited to these embodiments unless otherwise stated in the following description.

[0023] A. Implementation Method

[0024] The following description uses an inkjet printer 1, which ejects ink to form an image on recording paper PP, as an example to illustrate the liquid ejection device.

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

[0026] The following is for reference Figures 1-3 An example of the configuration 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 configuration of an inkjet printer 1.

[0028] like Figure 1 As shown, a host computer, such as a personal computer or digital camera, supplies inkjet printer 1 with printing data Img representing the image that inkjet printer 1 should form. Inkjet printer 1 performs a printing process, which is the process of forming the image shown by the printing data Img supplied from the host computer onto recording paper PP.

[0029] like Figure 1 As shown, the inkjet printer 1 includes: a control unit 2 for controlling various parts of the inkjet printer 1; a liquid ejection unit 3 provided with an ejection section D for ejecting ink from recording paper PP; a drive signal generation unit 5 provided with a drive signal generation circuit 50, the drive signal generation circuit 50 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 configuration including the control unit 2 and the drive signal generation unit 5 will be referred to as "drive control unit 8" below. In this embodiment, drive control unit 8 is an example of a "drive device."

[0031] In this embodiment, it is assumed that the inkjet printer 1 has one or more liquid ejection units 3. Specifically, in this embodiment, as an example, it is assumed that the inkjet printer 1 has four liquid ejection units 3. It should be noted that, for ease of explanation, the following will use... Figure 1 As shown, the explanation will focus on one of the four liquid ejection units 3.

[0032] Furthermore, in this embodiment, as an example, it is assumed that the drive signal generation unit 5 corresponds to one liquid ejection unit 3 and has one or more drive signal generation circuits 50. Specifically, in this embodiment, it is assumed that the drive signal generation unit 5 corresponds to one liquid ejection unit 3 and has two drive signal generation circuits 50. That is, in this embodiment, it is assumed that the drive signal generation unit 5 corresponds to four liquid ejection units 3 and has eight drive signal generation circuits 50. However, the present invention is not limited to this form. The drive signal generation unit 5 may also correspond to one liquid ejection unit 3 and have one drive signal generation circuit 50, or it may correspond to one liquid ejection unit 3 and have three or more drive signal generation circuits 50. It should be noted that, for ease of explanation, the following will use the following... Figure 1 As shown, the description focuses on one of the eight drive signal generation circuits 50.

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

[0034] The storage circuit 22 is composed of 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). However, the control circuit 21 may replace a CPU or, in addition to a CPU, also include a programmable logic device such as an FPGA (field-programmable gate array). Then, the control circuit 21 executes the control program for the inkjet printer 1 stored in the storage circuit 22, and controls various parts of the inkjet printer 1 by performing actions according to the control program. 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 to control 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 whether or not the drive signal Com is supplied to the ejector section D, thereby specifying the type of operation of the ejector section D, such as whether ink is ejected from 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 a specified signal SI, etc., based on the printing data Img to control the liquid ejection unit 3. Furthermore, during printing, the control unit 2 generates a waveform specified signal dCom, etc., to control the drive signal generation unit 5. Additionally, during printing, the control unit 2 generates carriage transport control signal SK and media transport control signal SB, etc., 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 whether ink is ejected 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 satisfying "M≥1". It should be noted that, hereinafter, there may be a case where the m-th ejector section D among the M ejector sections D provided in the head 32 is referred to as ejector section D[m]. Here, the variable m is a natural number satisfying "1≤m≤M". Furthermore, hereinafter, when a component or signal of the inkjet printer 1 corresponds to ejector section D[m] among the M ejector sections D, a superscript [m] may be added to the reference numerals used to represent that component or signal.

[0041] The supply circuit 31 switches whether to supply a drive signal Com to the ejector section D[m] based on a specified signal SI. Hereinafter, there is a case where the drive signal Com supplied to the ejector section D[m] is 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 schematic internal structure of an inkjet printer 1.

[0046] like Figure 2 As 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 simultaneously 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 X2 direction will be collectively referred to as the "X-axis direction," the Y1 direction intersecting the X-axis direction and its opposite Y2 direction will be collectively referred to as the "Y-axis direction," and the Z1 direction intersecting the X-axis direction and the Y-axis direction and its opposite Z2 direction will be collectively referred to as the "Z-axis direction." In this embodiment, as an example, the case where the X-axis direction, Y-axis direction, and Z-axis direction are orthogonal to each other will be described. However, the present invention is not limited to this form. The X-axis direction, Y-axis direction, and Z-axis direction may intersect each other. It should be noted that in this embodiment, the Z1 direction is the direction in which ink is ejected from the ejection section D.

[0048] like Figure 2As shown, the inkjet printer 1 according to this embodiment includes a housing 100 and a carriage 110 that can reciprocate within the housing 100 along the Y-axis. 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 assumed that the carriage 110 is equipped with four ink cartridges 120, each corresponding to one of the four colors of ink: cyan, magenta, yellow, and black. Furthermore, in this embodiment, as described above, it is assumed that the carriage 110 is equipped with four liquid ejection units 3, each corresponding to one of the four ink cartridges 120. Each ejection section D[m] receives ink from the ink cartridge 120 corresponding to the liquid ejection unit 3 on which the ejection section D[m] is located. Thus, each ejection section D[m] can be filled with the supplied ink and eject the ink filled inside the ejection section D[m] 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 2 As 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 the recording paper PP along the X1 direction; and an impression plate 95 disposed in the Z1 direction of the carriage 110 and supporting the recording paper PP. Therefore, when performing printing processing, the transport unit 9 can use the carriage transport motor 91 to make the liquid ejection unit 3 and the carriage 110 reciprocate along the carriage guide shaft 96 along the Y-axis direction, and use the media transport motor 92 to transport the recording paper PP on the impression plate 95 along the X1 direction, thereby changing the relative position of the recording paper PP with respect to the liquid ejection unit 3, so that ink can drip onto the entire recording paper PP.

[0051] Figure 3 This is a schematic partial cross-sectional view of the head 32, which is cut off in a manner including the ejection part D[m].

[0052] like Figure 3As shown, the ejector 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. The ejector section D[m] is driven by a drive signal Vin[m] supplied to the piezoelectric element PZ[m], 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 ejector 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 body Zm[m] disposed between the upper electrode Zu[m] and the lower electrode Zd[m]. The lower electrode Zd[m] is electrically connected to a power line LD set at a predetermined potential VBS. Then, when a supply 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] is displaced in the Z1 and Z2 directions according to the applied voltage, and as a result, the piezoelectric element PZ[m] vibrates. The lower electrode Zd[m] engages with a vibrating plate 321. Therefore, when the piezoelectric element PZ[m] is driven to vibrate by the supply drive signal Vin[m], the vibrating plate 321 also vibrates. Then, through the vibration of the vibrating plate 321, the volume of the cavity CV[m] and the pressure inside the cavity CV[m] change, and the ink filled in the cavity CV[m] is ejected by the nozzle N[m].

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

[0054] The following is for reference Figures 4-6 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 configuration 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. Furthermore, the liquid ejection unit 3 includes 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 status specifying circuit 310 generates a connection status specifying signal QS[m] for the on / off state of the specified switch WS[m] based on at least a portion of the specified signal SI, latch signal LAT, conversion signal CH, and clock signal CLK supplied from the 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 it is low. When the switch WS[m] is turned 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 the inkjet printer 1 performs printing processing, one or more unit periods TP are set as the operating periods of the inkjet printer 1. In this embodiment, the inkjet printer 1 can drive each ejection section D[m] to perform printing processing during 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 a unit period TP as the period from the rising edge of the pulse PLL to the rising edge of the next pulse PLL. Furthermore, control unit 2 outputs a conversion signal CH with a pulse PLC during the unit period TP. Then, 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 5 As shown, the designated signal SI includes M individual designated 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 designated signal Sd[m] specifies the driving form of the ejector section D[m] in each unit period TP. Before each unit period TP, the control unit 2 supplies the designated signal SI, which includes the M individual designated signals Sd[1] to Sd[M], to the connection state designation circuit 310 in sync with the clock signal CLK. Then, within the unit period TP, the connection state designation circuit 310 generates a connection state designation signal QS[m] based on the individual designated signals Sd[m].

[0064] It should be noted that in this embodiment, it is assumed that within a unit period TP of the printing process, the ejector part D[m] can form any of the following types of points: a large point formed by ink with an ink amount of ξ1, a medium point formed by ink with an ink amount of ξ2 less than ink amount of ξ1, and a small point formed by ink with an ink amount of ξ3 less than ink amount of ξ2.

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

[0066] like Figure 6 As shown, in this embodiment, the signal Sd[m] can be individually specified to form any one of the following four values ​​within the unit period TP of the printing process: value "1" for specifying the ejector part D[m] as the large dot forming ejector part DP-1, value "2" for specifying the ejector part D[m] as the medium dot forming ejector part DP-2, value "3" for specifying the ejector part D[m] as the small dot forming ejector part DP-3, and value "4" for specifying the ejector part D[m] as the non-dot 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. Furthermore, the mid-dot-forming ejection section DP-2 refers to the ejection section D that forms mid-dots within a unit period TP. Furthermore, the small-dot-forming ejection section DP-3 refers to the ejection section D that forms small dots within a unit period TP. Furthermore, 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 (which is lower than potential V0) and potential VHA1 (which is higher than potential V0). Waveform PA1 is defined as follows: when the supply drive signal Vin[m] with waveform PA1 is supplied to the ejection section D[m], ink equivalent to ink quantity 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 (which is lower than potential V0) and potential VHA2 (which is higher than potential V0). Waveform PA2 is defined as follows: when the supply drive signal Vin[m] with waveform PA2 is supplied to the ejection section D[m], ink equivalent to ink quantity φ2 is ejected from the ejection section D[m]. It should be noted that in this embodiment, it is assumed that ink quantity ξ1 is equivalent to the sum of ink quantity φ1 and ink quantity φ2, ink quantity ξ2 is equivalent to ink quantity φ1, and ink quantity ξ3 is equivalent to ink quantity 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] becomes 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] as the potential of the supply drive signal Vin[m] changes from low to high.

[0072] like Figure 6 As shown, within a unit period TP, when the individually specified signal Sd[m] indicates that the specified ejector part D[m] is the large dot forming ejector part DP-1 with a value of "1", 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 ejector part D[m] is driven by the supply driving signal Vin[m] with waveforms PA1 and PA2 within a unit period TP, ejecting ink equivalent to the ink amount ξ1 of the large dot.

[0073] Furthermore, during the unit period TP, when the individually specified signal Sd[m] indicates that the value "2" is "2" for the specified ejector part D[m] forming the ejector part DP-2 at the midpoint, 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, during the unit period TP, the ejector part D[m] is driven by the supply drive signal Vin[m] with waveform PA1, ejecting ink equivalent to the ink amount ξ2 at the midpoint.

[0074] Furthermore, during the unit period TP, when the individually specified signal Sd[m] indicates that the specified ejector part D[m] is the value "3" for the small dot formation ejector part DP-3, the connection state specifying circuit 310 sets the connection state specifying 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, during the unit period TP, the ejector part D[m] is driven by the supply driving signal Vin[m] with waveform PA2, ejecting ink equivalent to the ink amount ξ3 of the small dot.

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

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

[0077] The following is for reference Figure 7 An example of the configuration 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 51, a transistor pair 52, and an electrolytic capacitor CC. It generates an analog drive signal Com based on a digital waveform specification signal dCom, the analog drive signal Com having a waveform specified by the 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 after converting the analog signal to the waveform specification signal dCom.

[0080] The analog-to-digital converter 51 outputs a waveform specification signal QB, which includes a base supply signal QB1 and a base supply signal QB2, based on the digital waveform specification signal dCom. Specifically, after converting the waveform specification signal dCom into an analog input signal, the analog-to-digital converter 51 generates an analog signal representing the potential based on the input signal, namely the base supply signal QB1, and an analog signal representing the potential based on the input signal but with a lower potential than the base supply signal QB1, namely the base supply signal QB2. Then, the analog-to-digital converter 51 outputs the base supply signal QB1 from the output terminal Tn1 and the base supply signal QB2 from the 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] The transistor pair 52 is a so-called push-pull circuit, which has an NPN type bipolar transistor Tr1 and a PNP type bipolar transistor Tr2, and generates a drive signal Com based on the base supply signal QB1 and the base supply signal QB2.

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

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

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

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

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

[0088] Figure 8 This is an exploded perspective view showing an example of the configuration 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 assumed that the control board 200, the transistor board 501, and the analog-to-digital converter board 502 are configured to extend in 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, comprising bipolar transistors Tr1 and Tr2, is disposed on a transistor substrate 501 in a drive signal generation circuit 50. Specifically, in this embodiment, it is assumed that the pair of transistors 52 is disposed on a surface PL11, one of the plurality of 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 assumed that the drive signal generation circuit 50 comprises eight drive signal generation circuits 50. Therefore, in this embodiment, eight bipolar transistors Tr1 and eight bipolar transistors Tr2, comprising eight transistor pairs, are disposed on surface PL11 of the transistor substrate 501. It should be noted that, hereinafter, bipolar transistors Tr1 and Tr2 may be collectively referred to as bipolar transistor Tr.

[0093] An analog conversion circuit 51 and an electrolytic capacitor CC from a drive signal generation circuit 50 are disposed on an analog conversion circuit substrate 502. Specifically, in this embodiment, it is assumed that the analog conversion circuit 51 and the electrolytic capacitor CC are disposed 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 assumed that the drive signal generation circuit 50 has eight drive signal generation circuits 50. Therefore, in this embodiment, eight analog conversion circuits 51 and eight electrolytic capacitors CC are disposed 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 by the transistor pair 52 disposed on the transistor substrate 501. In this embodiment, it is assumed that the heat sink HS1 is connected to the surface PL12, which is the normal direction of the Z1 direction, among the multiple surfaces of the transistor substrate 501.

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

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

[0098] The analog-to-digital converter cooling mechanism CL2 includes a heat sink HS2 and a fan FN2. It should be noted that, in this embodiment, the analog-to-digital converter 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 by the analog-to-digital converter circuit 51 disposed on the analog-to-digital converter circuit board 502. In this embodiment, it is assumed that the heat sink HS2 is connected to surface PL21 of the plurality of surfaces of the analog-to-digital converter circuit board 502. However, the heat sink HS2 may also be directly connected to the analog-to-digital converter circuit 51 disposed on surface PL21 of the analog-to-digital converter circuit board 502.

[0100] It should be noted that, as will be described in detail 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. However, fan FN2 can also be connected to analog conversion circuit board 502 and cool analog conversion circuit board 502. Furthermore, fan FN2 can also be connected to analog conversion circuit 51 and cool analog conversion circuit 51. It should be noted that in this embodiment, it is assumed that fan FN2 remains operational while inkjet printer 1 is performing printing processing and drive signal generation circuit 50 generates drive signal Com. For example, in this embodiment, fan FN2 can 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 a surface PL11 of the transistor substrate 501, and a plug CN12 fixed to a surface PL22 of the analog-to-digital converter circuit substrate 502 with the Z1 direction as its normal, and capable of engaging with the socket CN11. The substrate-to-substrate connector CN1, through the engagement of the socket CN11 and the plug CN12, fixes the transistor substrate 501 and the analog-to-digital converter circuit substrate 502, 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 board-to-board connector CN2. Specifically, the board-to-board 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, and capable of mating with the socket CN21. The board-to-board connector CN2, through the mating of the socket CN21 and the plug CN22, fixes the analog-to-analog converter circuit board 502 and the control board 200, 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 in 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 an end in the X2 direction of the transistor substrate 501; a long side LY2 extending along the Y1 direction opposite to the long side LY1 and located at an end in the X1 direction of the transistor substrate 501; a short side LX1 extending along the X1 direction and located at an end in the Y2 direction of the transistor substrate 501; and a short side LX2 extending along the X1 direction opposite to the short side LX1 and located at an end in the Y1 direction of the transistor substrate 501. It should be noted that in this embodiment, the long side LY1 and the long side LY2 have approximately the same length, and the short side LX1 and the short side 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 considering errors. For example, "approximately the same" can also mean identical in design. Furthermore, the concept of "approximately the same" can also include cases where approximately 5% error is considered as identical.

[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 region AT1 and the end region AT2.

[0107] like Figure 9 As shown, in this embodiment, it is assumed that the sixteen bipolar transistors Tr of the drive signal generation circuit 50 are disposed in the end region AT1 or the end region AT2. Specifically, in this embodiment, it is assumed that eight of the sixteen bipolar transistors Tr of the drive signal generation circuit 50 are disposed in the end region AT1, and the remaining eight are disposed in the end region AT2. That is, in this embodiment, it is assumed 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 disposed in the central region AM, heat dissipation of the bipolar transistors Tr can be efficiently achieved from the long side LY1 or the long side LY2.

[0108] In addition, such as Figure 9As shown, in this embodiment, it is assumed that the substrate-to-substrate connector CN1 is disposed in the central region AM. Therefore, according to this embodiment, compared with the form where the substrate-to-substrate connector CN1 is disposed in the end region AT1 or the end region AT2, the variation in the relative position and relative orientation between the transistor substrate 501 and the analog conversion circuit substrate 502 can be reduced, and the transistor substrate 501 and the analog conversion circuit substrate 502 can be stably connected 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 electrode 62B, a collector electrode 62C, and an emitter electrode 62E. It should be noted that... Figure 10 Although the collector electrode 62C and the emitter electrode 62E are omitted from the diagram, the collector electrode 62C is present, for example, in the X1 direction of the base electrode 62B, and the emitter electrode 62E is present, for example, in the X2 direction of the base electrode 62B.

[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 electrode 62B via wiring 63B, wiring 711C electrically connected to the collector electrode 62C via wiring 63C (not shown), and wiring 711E electrically connected to the emitter electrode 62E via wiring 63E (not shown). It should be noted that in... Figure 10 Although 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... Figure 10Although the diagrams of connecting wires 721C and 721E are omitted, connecting wire 721C is configured, for example, to be insulated from connecting wire 721B in the X1 direction, and connecting wire 721E is configured, for example, to be insulated from connecting wire 721B in the X2 direction.

[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... 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, wiring 731E, and substrate 75 disposed on the wiring layer 73.

[0116] The substrate 75 is formed of aluminum. In this embodiment, it is assumed that the heat sink HS1 is connected to the substrate 75 via grease 64. However, the heat sink HS1 may also be connected to the substrate 75 via heat sink fins. It should be noted that the surface of the substrate 75 facing the Z1 direction 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 among the surfaces 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, the screws 65 are preferably 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. Furthermore, 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), are also available, their high cost makes them impractical for use as substrates in the drive signal generation unit 5. Therefore, copper substrates have traditionally been used as substrates for the drive signal generation unit 5.

[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 The specific gravity of stainless steel is 7.9 g / cm³. 3 In 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 using copper substrates. As a result, when the drive signal generation unit 5 according to this embodiment is mounted on the carriage 110 and moves, the load on the carriage transport motor 91 that drives the carriage 110 can be reduced. That is, compared with conventional drive signal generation units using 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 required to drive 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, the drive signal generation unit 5 according to this embodiment can simultaneously reduce the load on 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 heat dissipation. Moreover, the heat sink is usually made of aluminum. Therefore, when an aluminum heat sink is installed in a conventional copper-based drive signal generation unit, corrosion is likely to occur at the boundary between the copper substrate and the aluminum heat sink. Therefore, in existing copper-based drive signal generation units, when an aluminum heat sink is installed, a heat sink fin is usually inserted between the copper substrate and the aluminum heat sink to prevent corrosion at the boundary. Therefore, conventional copper-based drive signal generation units suffer from problems such as increased size, higher cost, and increased number of components.

[0125] In contrast, the drive signal generation unit 5 according to this embodiment uses an aluminum substrate as the transistor substrate 501, and the substrate 75 of the aluminum substrate is formed of aluminum. 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 insert a heat sink between the transistor substrate 501 and the heat sink HS1; instead, only grease 64 needs to be inserted between the transistor substrate 501 and the heat sink HS1. Thus, compared with the existing 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 parts.

[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 relative to current demand. Furthermore, aluminum is considered to be a metal with superior recyclability 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, an aluminum substrate 75 formed of aluminum is used in the drive signal generation unit 5. Therefore, according to this embodiment, compared to using a copper substrate in the drive signal generation unit 5, the environmental burden can be reduced, and the impact of future copper shortages can be mitigated.

[0127] A.5. Summary of Implementation Methods

[0128] According to this embodiment, since the transistor substrate 501 and the analog conversion circuit substrate 502 are made of aluminum substrate, the drive signal generation unit 5 can be made lighter compared to the conventional drive signal generation unit that uses a copper substrate. 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 that drives the carriage 110 can be reduced. That is, compared to the conventional drive signal generation unit that uses a copper substrate, 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 required to drive the carriage transport motor 91.

[0129] Furthermore, in the drive signal generation unit 5 according to this embodiment, an aluminum substrate is used as the transistor substrate 501, and the substrate 75 of the aluminum substrate is formed of aluminum. 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 insert 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 insert a heat sink between the analog conversion circuit substrate 502 and the heat sink HS2. Therefore, according to the drive signal generation unit 5 according to this embodiment, compared with the conventional drive signal generation unit using a copper substrate, it is possible to achieve miniaturization of the drive signal generation unit 5, cost reduction of the drive signal generation unit 5, and reduction of the number of parts in the drive signal generation unit 5.

[0130] Furthermore, in the drive signal generation unit 5 according to this embodiment, the analog conversion circuit substrate 502 where the analog conversion circuit 51 is provided and the transistor substrate 501 where the transistor pair 52 is provided are separate substrates. Therefore, compared with the form where the transistor pair 52 and the analog conversion circuit 51 are provided 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 analog conversion circuit 51, thereby suppressing the overheating of the analog conversion circuit 51.

[0131] Furthermore, in the drive signal generation unit 5 according to this embodiment, the control substrate 200 where the control circuit 21 is provided and the transistor substrate 501 where the transistor pair 52 is provided are separate substrates. Therefore, compared with the form where the transistor pair 52 and the control circuit 21 are provided 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, thereby suppressing the overheating of the control circuit 21.

[0132] Furthermore, in the drive signal generation unit 5 according to this embodiment, the transistor cooling mechanism CL1, which cools the transistor substrate 501 on which the transistor pair 52 is provided, and the analog conversion circuit cooling mechanism CL2, which cools the analog conversion circuit substrate 502 on which the analog conversion circuit 51 is provided, are independently provided. Therefore, compared with the form where the transistor cooling mechanism CL1, which cools the transistor substrate 501, also cools the analog conversion circuit substrate 502, 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 heating of 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-analog converter circuit board 502 are fixed by a substrate-to-substrate connector CN1. Therefore, according to this embodiment, compared with a form in which the transistor substrate 501 and the analog-to-analog converter circuit board 502 are connected, for example, by 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, it is possible to suppress the occurrence of offsets in the relative positions of the transistor substrate 501 and the analog-to-analog converter circuit board 502, as well as offsets in their relative orientations. Thus, according to this embodiment, the transistor substrate 501 and the analog-to-analog converter circuit board 502 can be stably connected. Similarly, according to this embodiment, the analog-to-analog converter circuit board 502 and the control board 200 can be stably connected.

[0134] B. Variations

[0135] Each of the above methods can be modified in various ways. Specific modifications are illustrated below. Any two or more forms selected from the following examples can be appropriately combined without contradiction. It should be noted that in the following examples of modifications, elements with the same function and implementation method as those referred to in the above description are used, and their detailed descriptions are appropriately omitted.

[0136] B.1. Variation Example 1

[0137] In the above embodiments, the analog conversion circuit board 502 is illustrated as an aluminum substrate with an aluminum base, but the present invention is not limited to this form. The analog conversion circuit board 502 may also be a copper substrate with a copper base. The analog conversion circuit board 502 may also be a metal substrate with a metal base.

[0138] Furthermore, in the above embodiment, the case where the heat sink HS2 is formed of aluminum was illustrated and described, but the present invention is not limited to this form. The heat sink HS2 may also be formed of copper. It should be noted that by using a copper substrate as the analog conversion circuit substrate 502 and forming the heat sink HS2 of copper, corrosion between the heat sink HS2 and the analog conversion circuit substrate 502 can be suppressed.

[0139] B.2. Variation Example 2

[0140] In the above embodiments and Modification 1, the transistor substrate 501 was illustrated as an aluminum substrate with substrate 75 formed of aluminum, but the present invention is not limited to this form. The transistor substrate 501 may also be a copper substrate with substrate 75 formed of copper. The transistor substrate 501 may also be a metal substrate with substrate formed of metal.

[0141] Furthermore, in the above embodiment, the case where the heat sink HS1 is formed of aluminum was illustrated and described, but the present invention is not limited to this form. The heat sink HS1 may also be formed of copper. It should be noted that by using a copper substrate as the transistor substrate 501 and forming the heat sink HS1 from copper, corrosion between the heat sink HS1 and the substrate 75 can be suppressed.

[0142] B.3. Variation Example 3

[0143] In the above-described embodiments and variations 1 and 2, a configuration in which one transistor pair 52 is provided in the drive signal generation circuit 50 corresponding to one analog-to-digital converter circuit 51 has been illustrated and described. However, the present invention is not limited to this configuration. Multiple transistor pairs 52 may also be provided corresponding to one analog-to-digital converter circuit 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 has the same configuration as 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 12As shown, the drive signal generation circuit 50B differs from the drive signal generation circuit 50 in that it replaces the analog conversion circuit 51B, replaces the transistor pair 52 and has multiple transistor pairs 52[1]~52[K], and replaces the electrolytic capacitor CC and has multiple electrolytic capacitors CC[1]~CC[K]. Here, the value K is a natural number that satisfies "K≥1". It should be noted that, below, there is a case where the kth transistor pair 52 of the K transistor pairs 52 provided in the drive signal generation circuit 50B is referred to as transistor pair 52[k]. Furthermore, below, there is a case where the kth electrolytic capacitor CC of the K electrolytic capacitors CC provided in the drive signal generation circuit 50B is 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, below, as Figure 12 The example shown illustrates the case where the value K is "2" and provides an explanation.

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

[0147] It should be noted that in this embodiment, it is assumed that the waveform designation signal dCom[1] and the waveform designation signal dCom[2] are signals that designate different waveforms from each other, but the present invention is not limited to this form. The waveform designation signal dCom[1] and the waveform designation signal dCom[2] can also be signals that designate the same waveform from each other.

[0148] Furthermore, in this embodiment, it is assumed 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 this form. 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] The 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 base supply signal QB1[k] and the base supply signal QB2[k].

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

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

[0152] The electrolytic capacitor CC[k] is a capacitor used to supply current to the transistor pair 52[k]. Specifically, the electrolytic capacitor CC[k] has two electrodes, one of which is electrically connected to the power line LH and the collector electrode of the 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 an analog-to-digital converter 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-described embodiments and variations 1 to 3, it was illustrated that fan FN1 maintains operation regardless of the temperature of the transistor pair 52 disposed on transistor substrate 501, and fan FN2 maintains operation regardless of the temperature of the analog conversion circuit 51 disposed on analog conversion circuit substrate 502. However, the present invention is not limited to this form. Fan FN1 may also be driven based on the temperature of the transistor pair 52 disposed on transistor substrate 501. Furthermore, fan FN2 may also be driven based on the temperature of the analog conversion circuit 51 disposed on analog conversion circuit substrate 502.

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

[0157] like Figure 13As shown, the inkjet printer 1C has the same configuration as the inkjet printer 1 described in the embodiment, except that it has a control unit 2C instead of a control unit 2, and a drive signal generation unit 5C instead of a drive signal generation unit 5. It should be noted that in this modified example, the configuration 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. Temperature sensor TS1 is configured, for example, to include a thermistor disposed on transistor substrate 501, and outputs temperature information DT1 representing temperature TT1 based on the temperature of transistor pair 52. Temperature sensor TS2 is configured, for example, to include a thermistor disposed on analog conversion circuit substrate 502, and outputs temperature information DT2 representing temperature TT2 based on the temperature of analog conversion circuit 51.

[0159] The control unit 2C differs from the control unit 2 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 to drive or stop the fan FN1 based on the temperature TT1 shown in the temperature information DT1. Thus, the control circuit 21C operates the fan FN1 based on the temperature TT1. More specifically, in this modified example, when the temperature TT1 is above a predetermined temperature, the control circuit 21C generates a fan control signal SF1 to operate the fan FN1; when the temperature TT1 is below the predetermined temperature, the control circuit 21C generates a fan control signal SF1 to stop the fan FN1. However, the invention is not limited to this form. For example, the control circuit 21C may generate a 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 a fan control signal SF1 to stop the fan FN1 when the difference 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] Based on the temperature TT2 shown in the temperature information DT2, the control circuit 21C generates a fan control signal SF2 to drive or stop the fan FN2. Thus, the control circuit 21C operates the fan FN2 based on the temperature TT2. More specifically, in this modified example, when the temperature TT2 is above a predetermined temperature, the control circuit 21C generates a fan control signal SF2 to operate the fan FN2; when the temperature TT2 is below the predetermined temperature, the control circuit 21C generates a fan control signal SF2 to stop the fan FN2. However, the present invention is not limited to this form. For example, the control circuit 21C may generate a 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 a fan control signal SF2 to stop the fan FN2 when the difference 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.

[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 involved in the operation of fan FN1 and fan FN2 can be reduced compared to the form in which fan FN1 and fan FN2 operate continuously.

[0163] B.5. Variation Example 5

[0164] In the above embodiments and variations 1 to 4, the case of fixing the transistor substrate 501 and the analog conversion circuit substrate 502 using a substrate connector CN1 was illustrated and described, but the present invention is not limited to this form. The transistor substrate 501 and the analog conversion circuit substrate 502 can also be fixed by a pin header. Here, the pin header is a connector comprising: an insertion pin member having a plurality of insertion pins formed of metal and a retaining portion held in a state of insulation from the plurality of insertion pins; and a pin socket having a plurality of insertion holes corresponding to the plurality of insertion pins.

[0165] In this embodiment, it is assumed that the insertion pin component in the pin header is fixed to surface PL11 of the transistor substrate 501, and the pin socket in 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 mating the insertion pin component with 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, the transistor cooling mechanism CL1 was illustrated and described as having a heat sink HS1 and a fan FN1, but the present invention is not limited to this form. The transistor cooling mechanism CL1 may also have a water-cooled cooling device.

[0168] Furthermore, in the above-described embodiments and variations 1 to 5, the analog-to-digital converter cooling mechanism CL2 is illustrated with a heat sink HS2 and a fan FN2, but the present invention is not limited to this form. The analog-to-digital converter cooling mechanism CL2 may also be equipped with a water-cooled cooling device.

[0169] B.7. Variation 7

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

[0173] B.9. Variation Example 9

[0174] In the above embodiments and variations 1 to 8, it was assumed that the inkjet printer 1 was a serial printer, but the present invention is not limited to this form. The inkjet printer 1 can also be a so-called line printer: configured such that multiple nozzles N in the liquid ejection unit 3 extend wider than the width of the recording paper PP.

[0175] C. Postscript

[0176] The following notes relate to the forms described above. It should be noted that, for ease of understanding, the reference numerals to the accompanying drawings are indicated in parentheses below, but this does not mean that the invention is limited to the illustrated forms.

[0177] C.1. Appendix 1

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

[0179] Appendix 1-1

[0180] The inkjet printer 1 described in Appendix 1-1 is characterized by comprising: a liquid ejection unit 3 that ejects ink driven by a drive signal Com; an analog conversion circuit 51 that converts a digital waveform specification signal dCom, specifying the waveform of the drive signal Com, into an analog waveform specification signal QB, specifying the waveform of the drive signal Com; a transistor pair 52 including two bipolar transistors Tr that generate the drive signal Com based on the waveform specification signal QB; 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.

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

[0182] According to Appendix 1-1, since the transistor cooling mechanism CL1 and the analog-to-digital converter cooling mechanism CL2 are provided separately, the high temperature of the analog-to-digital converter 51 can be suppressed compared to the form 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 high temperature of the analog-to-digital converter 51 can be suppressed.

[0183] Appendix 1-2

[0184] The inkjet printer 1 mentioned in Appendix 1-2 is characterized in that the output terminal Tn1 of the analog conversion circuit 51 is electrically connected to the base electrode 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 converter circuit 51 to the transistor pair 52 is a large current, the high temperature of the analog converter circuit 51 can be suppressed. Therefore, the instability of the operation of the analog converter circuit 51 caused by the high temperature of the analog converter circuit 51 can be suppressed.

[0186] Appendix 1-3

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

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

[0189] Appendix 1-4

[0190] The inkjet printer 1 described in Appendices 1-4, in the inkjet printer 1 described in Appendices 1-1 to 1-3, is characterized by comprising: a transistor substrate 501 provided with transistor pairs 52; an analog conversion circuit substrate 502 provided with an analog conversion circuit 51; a control circuit 21 for generating a waveform specification signal dCom; and a control substrate 200 provided with the control circuit 21, wherein the control substrate 200 and the analog conversion circuit substrate 502 are separately provided.

[0191] According to Appendix 1-4, compared with the form where the control board 200 and the analog conversion circuit board 502 are the same board, the high temperature of the control board 200 can be suppressed.

[0192] Appendix 1-5

[0193] The inkjet printer 1 mentioned in Appendix 1-5 is characterized in that the analog conversion circuit board 502 and the control board 200 are connected through the board connector CN2.

[0194] According to Appendix 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, in the inkjet printer 1 described in Appendices 1-4 or 1-5, is characterized in that the analog conversion circuit board 502 and the transistor board 501 are separately disposed.

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

[0198] Appendix 1-7

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

[0200] According to Appendix 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, 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.

[0201] Appendix 1-8

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

[0203] According to Appendix 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, 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.

[0204] Appendix 1-9

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

[0206] According to notes 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 a form in which the surface with the smallest area among the multiple surfaces of the bipolar transistor Tr is connected to the transistor substrate 501, or a form in which the multiple surfaces of the bipolar transistor Tr are not connected to the transistor substrate 501.

[0207] Postscript 1-10

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

[0209] It should be noted that in notes 1-10, the drive signal Com[1] is an example of the "first drive signal", the drive signal Com[2] is an example of the "second drive 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 high temperature.

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

[0212] Postscript 1-11

[0213] The inkjet printer 1 described in Appendix 1-11, in the inkjet printer 1 described in Appendix 1-1 to Appendix 1-10, is characterized in that the transistor cooling mechanism CL1 includes a heat sink HS1, which is connected to a transistor substrate 501 on which transistor pairs 52 are mounted, and is formed of aluminum; the analog conversion circuit cooling mechanism CL2 includes a heat sink HS2, which is connected to an analog conversion circuit 51 or an 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, the high temperature of the analog-to-digital converter 51 can be suppressed, and the instability of the operation of the analog-to-digital converter 51 can be suppressed.

[0215] Postscript 1-12

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

[0217] According to notes 1-12, the high temperature of the transistor 52 can be suppressed.

[0218] C.2. Appendix 2

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

[0220] Appendix 2-1

[0221] The inkjet printer 1 described in Appendix 2-1 is characterized by comprising: a liquid ejection unit 3 that ejects ink driven by a drive signal Com; a transistor substrate 501; a transistor pair 52 disposed on the transistor substrate 501, including two bipolar transistors Tr that generate the drive signal Com; an analog conversion circuit substrate 502; and an analog conversion circuit 51 disposed on the analog conversion circuit substrate 502 that converts a digital waveform specification signal dCom of the waveform of the drive signal Com into an analog waveform specification signal QB of 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 conversion circuit substrate 502 is disposed separately from the transistor substrate 501.

[0222] According to Appendix 2-1, since the transistor substrate 501 with transistor pair 52 is separated from the analog conversion circuit substrate 502 with analog conversion circuit 51, the propagation of heat from transistor pair 52 to analog conversion circuit 51 can be suppressed compared to a configuration where analog conversion circuit 51 and transistor pair 52 are mounted on the same substrate. Therefore, according to Appendix 2-1, the overheating 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 overheating can be suppressed.

[0223] Appendix 2-2

[0224] The inkjet printer 1 described in Appendix 2-2 is characterized by having a transistor cooling mechanism CL1 for cooling 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 generated by transistor pair 52 propagating to analog conversion circuit 51 can also be suppressed.

[0226] Appendix 2-3

[0227] The inkjet printer 1 described in Appendix 2-3, in the inkjet printer 1 described in Appendix 2-1 or Appendix 2-2, is characterized in that the transistor substrate 501 has a surface PL11; and a surface PL12 on the opposite side of the surface PL11, wherein 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 notes 2-3, face PL11 is an example of the "first face" and face PL12 is an example of the "second face".

[0229] According to Note 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 generated by transistor pair 52 propagating to analog conversion circuit 51 can also be suppressed.

[0230] Appendix 2-4

[0231] The inkjet printer 1 described in Appendix 2-4, in the inkjet printer 1 described in Appendix 2-2 or Appendix 2-3, is characterized in that 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 pair 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 generated by transistor pair 52 propagating to analog conversion circuit 51 can also be suppressed.

[0233] Appendix 2-5

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

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

[0236] Appendix 2-6

[0237] The inkjet printer 1 mentioned in Appendix 2-6, in the inkjet printer 1 mentioned in Appendix 2-1 to Appendix 2-5, is characterized in that the transistor substrate 501 and the analog conversion circuit substrate 502 are connected through the 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, and the transistor substrate 501 and the analog conversion circuit substrate 502 vibrate, a stable connection between the transistor substrate 501 and the analog conversion circuit substrate 502 can be maintained.

[0239] Appendix 2-7

[0240] The inkjet printer 1 mentioned in Appendix 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 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 in a stable connected state.

[0242] Appendix 2-8

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

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

[0245] According to Appendix 2-8, 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, even if the transistor substrate 501 and the analog conversion circuit substrate 502 vibrate, a stable connection between the transistor substrate 501 and the analog conversion circuit substrate 502 can be maintained.

[0246] Appendix 2-9

[0247] The inkjet printer 1 described in Appendix 2-9, in the inkjet printer 1 described in Appendix 2-1 to Appendix 2-8, is characterized in that the transistor substrate 501 includes: 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 notes 2-9, the heat generated by multiple bipolar transistors Tr can be efficiently dissipated from the long side LY1 and the long side LY2.

[0249] Postscript 2-10

[0250] The inkjet printer 1 described in Appendix 2-10, in the inkjet printer 1 described in Appendix 2-1 to Appendix 2-9, is characterized in that the bipolar transistor Tr is disposed on the transistor substrate 501 such that the surface 600 having the largest area among the multiple 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] Postscript 2-11

[0253] The inkjet printer 1 described in Appendix 2-11, in the inkjet printer 1 described in Appendix 2-1 to Appendix 2-10, is characterized in that the transistor substrate 501 has a surface PL11; and a surface PL12 on the opposite side of 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, and 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 Note 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] The inkjet printer 1 described in Appendix 3-1 is characterized by comprising: a liquid ejection unit 3 that ejects ink by being driven by a drive signal Com; a metal transistor substrate 501; and a transistor pair 52 disposed on the transistor substrate 501 and comprising 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 a form where the transistor pair 52 is disposed on a resin substrate. Therefore, according to Appendix 3-1, high temperatures in the transistor pair 52 can be suppressed.

[0260] Appendix 3-2

[0261] The inkjet printer 1 described in Appendix 3-2 is characterized by having a carriage 110 for moving the liquid ejection unit 3, and a transistor substrate 501 having a substrate 75 formed of aluminum and 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 to a substrate with a copper base as the transistor substrate 501, 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, the lifespan of the carriage transport motor 91 can be extended, and the power required to drive 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 it has a heat sink HS1 formed of aluminum and connected to the substrate 75 of the transistor substrate 501.

[0265] According to Note 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, for example, compared to the case where the radiator HS1 is made of copper, the radiator HS1 can be made lighter. Therefore, according to Appendix 3-3, the lifespan of the carriage transport motor 91 can be extended, and the power involved in driving the carriage transport motor 91 can be reduced.

[0267] Furthermore, according to Appendix 3-3, since the aluminum heat sink HS1 is connected to the transistor substrate 501 having an aluminum substrate 75, compared to a configuration where the aluminum heat sink HS1 is connected to the transistor substrate 501 using a substrate having a copper substrate, the possibility of corrosion at the boundary between the transistor substrate 501 and the heat sink HS1 can be reduced. Therefore, according to Appendix 3-3, it is not necessary to insert a heat sink between the transistor substrate 501 and the heat sink HS1; only grease 64 needs to be inserted between the transistor substrate 501 and the heat sink HS1. Thus, according to Appendix 3-3, compared to a configuration where a substrate having a copper substrate is used as the transistor substrate 501, 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 parts in the drive signal generation unit 5 can be achieved.

[0268] Appendix 3-4

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

[0270] According to notes 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, in the inkjet printer 1 described in Appendix 3-1 to Appendix 3-4, is characterized by comprising: 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 of a specified drive signal Com into an analog waveform specification signal QB of the specified drive signal Com, wherein a transistor pair 52 generates a drive signal Com based on the waveform specification signal QB, and the analog conversion circuit board 502 and the transistor board 501 are disposed separately.

[0273] According to Appendix 3-5, since the analog-to-digital converter circuit board 502 and the transistor board 501 are separately disposed, compared with the form in which the analog-to-digital converter circuit 51 and the transistor pair 52 are disposed on the same board, the propagation 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, and the instability of the operation of the analog-to-digital converter circuit 51 can be suppressed.

[0274] Appendix 3-6

[0275] The inkjet printer 1 described in Appendix 3-6, in the inkjet printer 1 described in Appendix 3-5, is characterized by comprising: 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 transistor cooling mechanism CL1 and the analog-to-digital converter cooling mechanism CL2 are independently provided, the high temperature 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 through a single cooling mechanism. Therefore, according to Appendix 3-6, the instability of the operation of the analog-to-digital converter 51 caused by the high temperature of the analog-to-digital converter 51 can be suppressed.

[0277] Appendix 3-7

[0278] The inkjet printer 1 described in Appendix 3-7 is characterized in that 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 by the transistor pair 52 can be effectively dissipated compared to the form in which the transistor pair 52 is disposed on a resin substrate.

[0280] Appendix 3-8

[0281] The inkjet printer 1 described in Appendix 3-8, in the inkjet printer 1 described in Appendix 3-1 to Appendix 3-7, is characterized in that the bipolar transistor Tr is disposed on the transistor substrate 501 such that the surface 600 having 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 a form in which the surface with the smallest area among the multiple surfaces of the bipolar transistor Tr is connected to the transistor substrate 501, or a form in which the multiple surfaces of the bipolar transistor Tr are not connected to the transistor substrate 501.

Claims

1. A liquid ejection device, characterized in that, have: The liquid ejector head ejects liquid via a drive signal; The first substrate is made of metal; and A pair of transistors is disposed on the first substrate and includes two bipolar transistors that generate the drive signal.

2. The liquid ejection device according to claim 1, characterized in that, The liquid ejection device includes a slide for moving the liquid ejection head. The first substrate has a base material formed of aluminum and is mounted on the carriage.

3. The liquid ejection device according to claim 2, characterized in that, The liquid ejection device includes a first heat sink that is connected to the substrate of the first substrate and is formed of aluminum.

4. The liquid ejection device according to claim 1, characterized in that, The liquid ejection device includes a first fan that operates based on the temperature of the transistor pair.

5. The liquid ejection device according to claim 1, characterized in that, The liquid ejection device includes: Second substrate; and An analog-to-digital converter circuit, disposed on the second substrate, converts 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 transistors generate the drive signal based on the second waveform signal. The second substrate is disposed separately from the first substrate.

6. The liquid ejection device according to claim 5, characterized in that, The liquid ejection device includes: A first cooling mechanism cools the transistor pair; and The second cooling mechanism cools the analog conversion circuit.

7. The liquid ejection device according to claim 1, characterized in that, The first substrate has a base material formed of copper.

8. 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 multiple faces of the bipolar transistor is connected to the first substrate.

9. A driving device, characterized in that, The driving device supplies the driving signal to the liquid nozzle that sprays liquid by being driven by the driving signal, and the driving device comprises: The first substrate is made of metal; and A pair of transistors is disposed on the first substrate and includes two bipolar transistors that generate the drive signal.

10. The driving device according to claim 9, characterized in that, The first substrate has a base material formed of aluminum and is mounted on a carriage that moves the liquid ejector head.

11. The driving device according to claim 10, characterized in that, The drive device includes a first heat sink that is connected to the substrate of the first substrate and is formed of aluminum.

12. The driving device according to claim 9, characterized in that, The drive unit includes a first fan that operates based on the temperature of the transistor pair.

13. The driving device according to claim 9, characterized in that, The drive device includes: Second substrate; and An analog-to-digital converter circuit, disposed on the second substrate, converts 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 transistors generate the drive signal based on the second waveform signal. The second substrate is disposed separately from the first substrate.

14. The driving device according to claim 13, characterized in that, The drive device includes: A first cooling mechanism cools the transistor pair; and The second cooling mechanism cools the analog conversion circuit.

15. The driving device according to claim 9, characterized in that, The first substrate has a base material formed of copper.

16. The driving device according to claim 9, characterized in that, The bipolar transistor is disposed on the first substrate such that the largest of the multiple faces of the bipolar transistor is connected to the first substrate.

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