Liquid ejecting apparatus and liquid ejecting unit

Abstract

The invention relates to a liquid ejecting apparatus and a liquid ejecting unit, which can effectively dissipate heat in a first transistor. A liquid ejecting apparatus includes: a liquid ejecting unit including a drive element driven by a drive signal, the liquid ejecting unit ejecting a liquid according to driving of the drive element; and a drive signal generation unit that generates a drive signal, the drive signal generation unit including: an integrated circuit that outputs a first control signal and a second control signal; a first transistor to which a first control signal is input; a second transistor to which a second control signal is input; a coil, one end of which is electrically connected to the first transistor and the second transistor and the other end of which is electrically connected to an output terminal that outputs a drive signal; a substrate on which the integrated circuit, the first transistor, the second transistor, and the coil are mounted; and a molded part covering the first transistor on the substrate, the first transistor having a Cu clip structure.

Description

Technical Field

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

[0002] A liquid ejection device is known, comprising: a liquid ejection unit configured to eject a liquid such as ink in response to a drive signal; and a drive signal generation unit configured to generate a drive signal. For example, Patent Document 1 discloses a liquid ejection device having a drive signal generation unit, characterized in that the drive signal generation unit comprises: an integrated circuit configured to output a first control signal and a second control signal; a first transistor configured to receive the first control signal; a second transistor configured to receive the second control signal; a coil having one end electrically connected to the first transistor and the second transistor and the other end electrically connected to an output terminal for outputting the drive signal; and a substrate on which the integrated circuit, the first transistor, the second transistor, and the coil are mounted, and wherein heat generated in the first transistor is dissipated from the substrate via a plurality of electrodes provided on a first surface facing the substrate, among a plurality of surfaces of a chip body (also referred to as a "chip") included in the first transistor.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-117049

[0004] However, the drive signal used to drive the liquid ejection unit has a large amplitude, and the heat generated in the first transistor during the generation of the drive signal is high. Therefore, when the heat generated in the first transistor is dissipated from the substrate via multiple electrodes provided on the first surface of the chip body of the first transistor, as in the conventional technique, the heat generated in the first transistor may exceed the amount of heat dissipated from the substrate, causing the temperature of the first transistor to rise. Furthermore, if the temperature of the first transistor rises, the operation of the drive signal generation unit may become unstable. Summary of the Invention

[0005] In order to solve the above technical problems, the liquid ejection device involved in the present invention is characterized in that it comprises: a liquid ejection unit, which has a driving element driven by a driving signal and ejects liquid according to the driving of the driving element; and a driving signal generating unit, which generates the driving signal, and the driving signal generating unit comprises: an integrated circuit, which outputs a first control signal and a second control signal; a first transistor, which is input with the first control signal; a second transistor, which is input with the second control signal; a coil, one end of which is electrically connected to the first transistor and the second transistor, and the other end of which is electrically connected to the output terminal that outputs the driving signal; a substrate, on which the integrated circuit, the first transistor, the second transistor and the coil are installed; and a molded part, which covers the first transistor on the substrate, and the first transistor has a Cu clip structure.

[0006] In addition, the liquid ejection unit involved in the present invention has a driving element driven by a driving signal, and ejects liquid according to the drive of the driving element. The liquid ejection unit is characterized in that it has: an integrated circuit, which outputs a first control signal and a second control signal; a first transistor, which is input with the first control signal; a second transistor, which is input with the second control signal; a coil, one end of which is electrically connected to the first transistor and the second transistor, and the other end of which is electrically connected to the output terminal that outputs the driving signal; a substrate, on which the integrated circuit, the first transistor, the second transistor and the coil are installed; and a molded part, which covers the first transistor on the substrate, and the first transistor has a Cu clip structure. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0009] Figure 3 It is a cross-sectional view showing an example of the structure of the ejection portion D[m].

[0010] Figure 4 3 is a block diagram showing an example of the configuration of the drive signal generating circuit 4 .

[0011] Figure 5 It is a block diagram showing an example of the structure of the liquid ejection unit 3.

[0012] Figure 6 3 is a timing chart showing an example of a signal supplied to the liquid ejection unit 3 .

[0013] Figure 7 : is an explanatory diagram showing an example of the individual designation signal Sd[m].

[0014] Figure 8 1 is a cross-sectional view showing an example of the structure of the drive signal generating unit 5 .

[0015] Figure 9 1 is a cross-sectional view showing an example of the structure of a drive signal generating unit 5W according to a conventional example.

[0016] Figure 10 1 is an explanatory diagram showing the outline of the drive signal generating unit 5 and the drive signal generating unit 5W.

[0017] Figure 11 It is a cross-sectional view showing an example of the structure of a drive signal generating unit 5B according to the second embodiment of the present invention.

[0018] Figure 12 It is an explanatory diagram showing an example of the composition of the reaction solution.

[0019] Figure 13 It is a cross-sectional view showing an example of the structure of a drive signal generating unit 5C according to the third embodiment of the present invention.

[0020] Figure 14 This is a block diagram showing an example of the configuration of an inkjet printer 1D according to Modification 1 of the present invention.

[0021] Figure 15 It is a cross-sectional view showing an example of the structure of a drive signal generating unit 5B according to Modification 2 of the present invention.

[0022] Figure 16 1 is a cross-sectional view showing an example of the structure of a drive signal generating unit 5C according to Modification 2 of the present invention.

[0023] Description of Reference Numerals

[0024] 1: Inkjet printer; 2: Control unit; 3: Liquid ejection unit; 4: Drive signal generating circuit; 5: Drive signal generating unit; 9: Conveying unit; 31: Supply circuit; 32: Liquid ejection head; 40: Integrated circuit; 41: Amplification circuit; 42: Smoothing circuit; 43: Pull-up circuit; 44: Filter circuit; 51: Substrate; 52: Heat sink; 55: Molded component; 56: Heat sink; 60: Chip main body; 61d: Drain electrode; 61g: Gate electrode; 61s: Source electrode; 62d: Drain connection terminal; 62g: Gate connection terminal; 62s: Source connection terminal; 63: Clip; 64: Wire; 91: Slide conveying motor; 92: Medium conveying motor; 93: Medium conveying mechanism; 110: Slide; 520: Main body; 521: Coating part; D: Ejection part; L0: Inductor element; Tr1: Transistor; Tr2: Transistor. DETAILED DESCRIPTION

[0025] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions and scales of the various components in the drawings may differ from actual dimensions. Furthermore, the embodiments described below are preferred examples of the present invention and, therefore, are subject to various technically preferred limitations. However, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

[0026] A. First embodiment

[0027] In the first embodiment, the liquid ejecting device will be described by taking as an example an inkjet printer 1 that ejects ink to form an image on recording paper PP.

[0028] A.1. Overview of inkjet printers

[0029] Below, refer to Figures 1 to 3 An example of the structure of the inkjet printer 1 according to the first embodiment will be described.

[0030] Figure 1 This is a functional block diagram showing an example of the configuration of the inkjet printer 1 .

[0031] like Figure 1 As shown, print data Img representing an image to be formed by the inkjet printer 1 is supplied from a host computer such as a personal computer or a digital camera to the inkjet printer 1. The inkjet printer 1 executes a print process to form the image represented by the print data Img supplied from the host computer on recording paper PP.

[0032] like Figure 1 As shown, the inkjet printer 1 includes: a control unit 2 for controlling the various parts of the inkjet printer 1; a liquid ejection unit 3, provided with an ejection part D for ejecting ink to the recording paper PP; a drive signal generating unit 5, provided with a drive signal generating circuit 4 for generating a drive signal Com for driving the ejection part D; and a conveying unit 9 for conveying the liquid ejection unit 3 and the recording paper PP.

[0033] In the first embodiment, the inkjet printer 1 is an example of a “liquid ejecting device,” ink is an example of a “liquid,” and recording paper PP is an example of a “medium.”

[0034] In the first embodiment, it is assumed that the inkjet printer 1 includes one or more liquid ejecting units 3 and one or more drive signal generating units 5 corresponding to the one or more liquid ejecting units 3. Specifically, in the first embodiment, it is assumed that the inkjet printer 1 includes four liquid ejecting units 3 and four drive signal generating units 5 corresponding to the four liquid ejecting units 3. However, for the sake of convenience, Figure 1 As shown, the description may be made focusing on one of the four liquid ejecting units 3 and one driving signal generating unit 5 provided corresponding to one of the four driving signal generating units 5 .

[0035] Control unit 2 is configured to include one or more CPUs (Central Processing Units). However, control unit 2 may also include a programmable logic device such as an FPGA (Field-Programmable Gate Array) in place of or in addition to a CPU. Control unit 2 also includes memory. The memory may include one or both 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 ROM).

[0036] The control unit 2 generates signals for controlling the operation of various components of the inkjet printer 1 , such as a designation signal SI, a waveform designation signal dCom, a carriage transport control signal SK, and a medium transport control signal SB.

[0037] Here, the waveform designation signal dCom is a digital signal that specifies the waveform of the drive signal Com. The drive signal Com is an analog signal for driving the ejection unit D. The designation signal SI is a digital signal that specifies the type of operation of the ejection unit D. Specifically, the designation signal SI specifies the type of operation of the ejection unit D, such as whether or not the drive signal Com is supplied to the ejection unit D. The carriage transport control signal SK and the medium transport control signal SB are signals used to control the transport unit 9.

[0038] When printing, the control unit 2 generates signals such as the designation signal SI for controlling the liquid ejection unit 3 based on the print data Img. Furthermore, when printing, the control unit 2 generates signals such as the waveform designation signal dCom for controlling the drive signal generation unit 5. Furthermore, when printing, the control unit 2 generates signals such as the carriage transport control signal SK and the medium transport control signal SB for controlling the transport unit 9. Thus, during the printing process, the control unit 2 controls the transport unit 9 to move the liquid ejection unit 3 and the recording paper PP, and controls various components of the inkjet printer 1 to adjust the presence and timing of ink ejection from the ejection portion D, thereby forming an image corresponding to the print 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 liquid ejection head 32 .

[0040] The liquid ejection head 32 includes M ejection units D. Here, the value M is a natural number satisfying "M ≥ 1." Hereinafter, the mth ejection unit D among the M ejection units D provided in the liquid ejection head 32 may be referred to as ejection unit D[m]. Herein, the variable m is a natural number satisfying "1 ≤ m ≤ M." Furthermore, when a component or signal of the inkjet printer 1 corresponds to an ejection unit D[m] among the M ejection units D, the reference numerals representing such component or signal may be suffixed with "m."

[0041] The supply circuit 31 switches whether to supply the drive signal Com to the ejection portion D[m] based on the designation signal SI. Hereinafter, the drive signal Com supplied to the ejection portion D[m] among the drive signals Com may be referred to as the supply drive signal Vin[m].

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

[0043] The carriage transport motor 91 transports a carriage 110 described later based on a carriage transport control signal SK.

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

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

[0046] like Figure 2 As shown, in the first embodiment, the inkjet printer 1 is assumed to be a serial printer. Specifically, when printing, the inkjet printer 1 transports recording paper PP in the X1 direction and ejects ink from the liquid ejection unit 3 while moving the liquid ejection unit 3 in the Y1 direction intersecting the X1 direction or in the Y2 direction opposite to the Y1 direction. This forms an image corresponding to the print data Img on the recording paper PP.

[0047] Hereinafter, the X1 direction and the X2 direction, which is its opposite direction, will be collectively referred to as the "X-axis direction," the Y1 direction, which intersects the X-axis direction, and the Y2 direction, which is its opposite direction, will be collectively referred to as the "Y-axis direction," and the Z1 direction, which intersects the X-axis direction and the Y-axis direction, and the Z2 direction, which is its opposite direction, will be collectively referred to as the "Z-axis direction." In the first embodiment, as an example, the description assumes that the X-axis direction, the Y-axis direction, and the Z-axis direction are mutually orthogonal. However, the present invention is not limited to this embodiment. The X-axis direction, the Y-axis direction, and the Z-axis direction may be mutually intersecting. Furthermore, in the first embodiment, the Z1 direction is the direction in which ink is ejected from the ejection portion D.

[0048] like Figure 2 As shown, the inkjet printer 1 according to the first embodiment includes a housing 100 and a carriage 110 that is reciprocatable in the Y-axis direction within the housing 100. The carriage 110 carries four liquid ejection units 3 and four drive signal generation units 5.

[0049] like Figure 2 As shown, in the first embodiment, the carriage 110 is assumed to be equipped with four ink cartridges 120 corresponding one-to-one to the four ink colors of cyan, magenta, yellow, and black. Furthermore, in the first embodiment, as described above, the carriage 110 is assumed to be equipped with four liquid ejection units 3 corresponding one-to-one to the four ink cartridges 120. Each ejection portion D[m] receives a supply of ink from the ink cartridge 120 corresponding to the liquid ejection unit 3 in which the ejection portion D[m] is located. Thus, each ejection portion D[m] can be filled with the supplied ink and eject the ink filled in the ejection portion D[m] from the nozzle N provided in the ejection portion D[m]. Alternatively, the ink cartridges 120 can be located external to the carriage 110.

[0050] Furthermore, as described above, the inkjet printer 1 according to the first embodiment includes the transport unit 9. Figure 2 As shown, the transport unit 9 includes a carriage transport motor 91 for reciprocating the carriage 110 in the Y-axis direction; a carriage guide shaft 96 for supporting the carriage 110 so that it can reciprocate in the Y-axis direction; a belt 97 for transporting the carriage 110 in the Y-axis direction when driven by the carriage transport motor 91; a medium transport motor 92 for transporting the recording paper PP in the X1 direction; a medium transport mechanism 93 that rotates when driven by the medium transport motor 92 to transport the recording paper PP in the X1 direction; and a platen 95 disposed in the Z1 direction of the carriage 110 to support the recording paper PP. Therefore, when printing is executed, the transport unit 9 reciprocates the liquid ejection unit 3 along with the carriage 110 in the Y-axis direction along the carriage guide shaft 96 via the carriage transport motor 91, and transports the recording paper PP on the platen 95 in the X1 direction via the media transport motor 92. This changes the relative position of the recording paper PP with respect to the liquid ejection unit 3, allowing ink to be deposited on the entire recording paper PP.

[0051] In addition, in the first embodiment, the carriage transport motor 91 is an example of a “motor”.

[0052] Figure 3 4 is a schematic partial cross-sectional view of the liquid ejecting head 32 cut so as to include the ejection portion D[m].

[0053] like Figure 3As shown, the ejection unit D[m] includes a piezoelectric element PZ[m], a cavity CV filled with ink, a nozzle N connected to the cavity CV, and a vibrating plate 321. The ejection unit D[m] drives the piezoelectric element PZ[m] by supplying a drive signal Vin[m], thereby ejecting the ink within the cavity CV from the nozzle N. The cavity CV is a space defined by a cavity plate 324, a nozzle plate 323 on which the nozzle N is formed, and the vibrating plate 321. The cavity CV is connected to a reservoir 325 via an ink supply port 326. The reservoir 325 is connected to the ink cartridge 120 corresponding to the ejection unit D[m] via an ink inlet 327. The piezoelectric element PZ[m] includes an upper electrode Zu[m], a lower electrode Zd[m], and a piezoelectric body Zm[m] disposed between the upper and lower electrodes Zu[m]. The lower electrode Zd[m] is electrically connected to a power supply line LD set to a predetermined potential VBS. Furthermore, a drive signal Vin[m] is supplied to the upper electrode Zu[m]. When a voltage is applied between the upper electrode Zu[m] and the lower electrode Zd[m], the piezoelectric element PZ[m] displaces in the Z1 and Z2 directions according to the applied voltage, causing the piezoelectric element PZ[m] to vibrate. The lower electrode Zd[m] is connected to the vibration plate 321. Therefore, when the piezoelectric element PZ[m] is driven to vibrate by the drive signal Vin[m], the vibration plate 321 also vibrates. Furthermore, the volume of cavity CV and the pressure within cavity CV change in response to the vibration of the vibration plate 321, and the ink filling cavity CV is ejected from the nozzle N. A portion of the ink ejected from the nozzle N is atomized and floats within the housing 100.

[0054] In the first embodiment, the piezoelectric element PZ[m] is an example of a “driving element”.

[0055] A.2. Configuration of the drive signal generating circuit 4

[0056] Below, refer to Figure 4 , an example of the structure of the drive signal generating circuit 4 provided in the drive signal generating unit 5 is described.

[0057] Figure 4 2 is a diagram showing an example of the circuit configuration of the drive signal generating circuit 4 .

[0058] like Figure 4 As shown, the drive signal generating circuit 4 includes an integrated circuit 40 , an amplifier circuit 41 , a smoothing circuit 42 , a pull-up circuit 43 , and a filter circuit 44 , and generates a drive signal Com based on a waveform designating signal dCom.

[0059] The integrated circuit 40 is, for example, an LSI (Large Scale Integration) and generates gate signals SG1 and SG2 based on the waveform designation signal dCom. Here, gate signal SG1 is an example of a "first control signal" and gate signal SG2 is an example of a "second control signal."

[0060] The integrated circuit 40 includes an analog conversion circuit 402 , a subtractor 404 , an adder 406 , an attenuator 408 , an integrating attenuator 412 , a comparator 420 , and a gate driver 430 .

[0061] Analog conversion circuit 402 is a DAC (digital-to-analog converter) that converts the digital waveform-specifying signal dCom into an analog signal Aa. The voltage amplitude of signal Aa is, for example, approximately 0 to 2 volts. This voltage is amplified approximately 20 times to form drive signal Com. In other words, signal Aa is the pre-amplified version of drive signal Com.

[0062] The integrating attenuator 412 attenuates a signal SN1 input to a terminal Tn1 described later and outputs an integrated signal Ax.

[0063] The subtractor 404 outputs a signal Ab indicating a potential obtained by subtracting the potential of the signal Aa from the potential of the signal Ax.

[0064] The attenuator 408 outputs a signal Ay obtained by attenuating a high-frequency component of a signal SN2 input to a terminal Tn2 described later.

[0065] The adder 406 outputs a signal As indicating a potential obtained by adding the potential of the signal Ab and the potential of the signal Ay.

[0066] Comparator 420 outputs a modulation signal Ms, which is a pulse-modulated signal of signal As. Specifically, comparator 420 outputs a modulation signal Ms that becomes high when the voltage of signal As rises and exceeds threshold voltage Vth1, and becomes low when the voltage of signal As falls and falls below threshold voltage Vth2. Threshold voltages Vth1 and Vth2 are set to satisfy the relationship "Vth1 > Vth2."

[0067] The power supply voltage of the circuit from the analog conversion circuit 402 to the comparator 420 is a low voltage, such as 3.3 V. In contrast, the drive signal Com has a large amplitude, sometimes exceeding 40 V, for example. Therefore, the integrator attenuator 412 attenuates the signal SN1 having an amplitude corresponding to the drive signal Com, thereby matching the amplitude range of the signal Ax with the amplitude range of the signal in the circuit from the analog conversion circuit 402 to the comparator 420.

[0068] Furthermore, in the first embodiment, a digital signal is used as an example to describe the waveform designating signal dCom. However, the waveform designating signal dCom may be any signal that specifies a target value for generating the drive signal Com. For example, an analog signal Aa may be used as the waveform designating signal dCom. If the signal Aa is the waveform designating signal dCom, the integrated circuit 40 may be configured without including the analog conversion circuit 402.

[0069] The gate driver 430 outputs a gate signal SG1 obtained by converting the modulation signal Ms into a specific amplitude to the terminal TnG1 , and outputs a gate signal SG2 obtained by converting the modulation signal Ms into a specific amplitude by inverting the logic level of the modulation signal Ms into a specific amplitude to the terminal TnG2 .

[0070] The amplifier circuit 41 includes, for example, transistors Tr1 and Tr2. Based on gate signals SG1 and SG2 output from the integrated circuit 40, it generates an amplified signal Az, which is an amplified signal of the modulation signal Ms. Here, transistor Tr1 is an example of a "first transistor," and transistor Tr2 is an example of a "second transistor." Hereinafter, transistors Tr1 and Tr2 may be collectively referred to as transistors Tr. Furthermore, in the first embodiment, as an example, transistors Tr1 and Tr2 are assumed to be N-channel field-effect transistors, or FETs (field-effect transistors).

[0071] like Figure 4 As shown, gate signal SG1 output from gate driver 430 is input to the gate electrode of transistor Tr1 via terminal TnG1 and resistor RG1. Gate signal SG2 output from gate driver 430 is input to the gate electrode of transistor Tr2 via terminal TnG2 and resistor RG2. The logic levels of gate signal SG1 and gate signal SG2 are mutually exclusive.

[0072] Here, "mutually exclusive" means that the signal levels of gate signal SG1 supplied to the gate electrode of transistor Tr1 and gate signal SG2 supplied to the gate electrode of transistor Tr2 will not be high at the same time. In other words, transistors Tr1 and Tr2 will not be turned on at the same time. Furthermore, transistor Tr1 is turned on when gate signal SG1 supplied to the gate electrode of transistor Tr1 is high, and is turned off when gate signal SG1 supplied to the gate electrode of transistor Tr1 is low. Furthermore, transistor Tr2 is turned on when gate signal SG2 supplied to the gate electrode of transistor Tr2 is high, and is turned off when gate signal SG2 supplied to the gate electrode of transistor Tr2 is low.

[0073] like Figure 4 As shown, the drain electrode of transistor Tr1 is electrically connected to a power supply line set to a power supply potential VHH, and the source electrode is electrically connected to a node Nd. The source electrode of transistor Tr2 is electrically connected to a power supply line set to a reference potential VLL lower than the power supply potential VHH, and the drain electrode is electrically connected to the node Nd. The reference potential VLL may be, for example, ground potential or the same potential as VBS.

[0074] As described above, transistor Tr1 is turned on when gate signal SG1 supplied to its gate electrode is at a high level, and is turned off when it is at a low level. Furthermore, transistor Tr2 is turned on when gate signal SG2 supplied to its gate electrode is at a high level, and is turned off when it is at a low level. Therefore, an amplified signal Az, which is obtained by amplifying the modulation signal Ms, is output to node Nd, which electrically connects the source electrode of transistor Tr1 and the drain electrode of transistor Tr2.

[0075] Smoothing circuit 42 is an LPF (low-pass filter) that smooths the amplified signal Az to generate a drive signal Com. Smoothing circuit 42 includes an inductor L0 and a capacitor C0. One end of the inductor L0 is electrically connected to node Nd, and the other end is electrically connected to output terminal Tn-out. In this context, inductor L0 is an example of a "coil." One end of capacitor C0 is electrically connected to output terminal Tn-out, and the other end is electrically connected to a power supply line set to a reference potential VLL. The drive signal Com, a result of smoothing the amplified signal Az, is output from output terminal Tn-out.

[0076] Pull-up circuit 43 pulls up drive signal Com output from output terminal Tn-out and feeds back signal SN1 to terminal Tn1. Pull-up circuit 43 includes a resistor R1 having one end electrically connected to output terminal Tn-out and the other end electrically connected to terminal Tn1; and a resistor R2 having one end electrically connected to terminal Tn1 and the other end electrically connected to a power supply line set at power supply potential VHH.

[0077] Filter circuit 44 is a BPF (band pass filter) that feeds signal SN2, after removing the DC component from frequency components in a predetermined frequency band within the drive signal Com, back to terminal Tn2. Filter circuit 44 includes: resistor R3; capacitor C1, one end of which is electrically connected to output terminal Tn-out and the other end to one end of resistor R3; resistor R4, one end of which is electrically connected to one end of resistor R3 and the other end to a power supply line set to a reference potential VLL; capacitor C2, one end of which is electrically connected to the other end of resistor R3 and the other end to the power supply line set to a reference potential VLL; and capacitor C3, one end of which is electrically connected to the other end of resistor R3 and the other end to terminal Tn2. Capacitor C1 and resistor R4 function as an HPF (high pass filter) that passes high-frequency components above the cutoff frequency within the drive signal Com. Resistor R3 and capacitor C2 function as an LPF (low pass filter) that passes low-frequency components below the cutoff frequency within the drive signal Com. In the first embodiment, the cutoff frequency of the HPF in the filter circuit 44 is set lower than the cutoff frequency of the LPF. Therefore, the filter circuit 44 passes frequency components in a predetermined frequency band above the HPF cutoff frequency and below the LPF cutoff frequency in the drive signal Com. Furthermore, the filter circuit 44 includes a capacitor C3. Therefore, the filter circuit 44 removes the DC component from the frequency components in the predetermined frequency band that have passed through the HPF and LPF in the drive signal Com and feeds the signal back to the terminal Tn2.

[0078] In this manner, the drive signal generation circuit 4 smoothes the amplified signal Az at node Nd via the smoothing circuit 42, thereby generating the drive signal Com. Drive signal Com, after integration and subtraction by the integrator attenuator 412, is fed back to the subtractor 404. Consequently, it self-oscillates at a frequency determined by the delay in the smoothing circuit 42, the delay in the integrator attenuator 412, and the feedback transfer function. However, due to the significant delay in the feedback path through terminal Tn1, feedback via terminal Tn1 alone cannot raise the frequency of self-oscillation to a level sufficient to ensure the waveform accuracy of the drive signal Com. In contrast, in the first embodiment, a path for feeding back the high-frequency component of the drive signal Com is provided via terminal Tn2, separate from the path via terminal Tn1. This reduces feedback delay in the entire drive signal generation circuit 4. Specifically, in the first embodiment, the frequency of signal As, which is the sum of signal Ay, the high-frequency component of the drive signal Com, to signal Ab, can be increased compared to a case where the path via terminal Tn2 is not present, thereby ensuring sufficient accuracy of the drive signal Com.

[0079] Furthermore, in the first embodiment, a case where the drive signal Com includes frequency components exceeding 50 kHz is assumed. If the frequency of the modulation signal Ms is set lower than 1 MHz, as in the first embodiment, when the drive signal Com includes frequency components exceeding 50 kHz, blunting occurs at the edges of the waveform of the drive signal Com, reducing the accuracy of the waveform of the drive signal Com. Furthermore, when the accuracy of the waveform of the drive signal Com is reduced, the accuracy of ink ejection from the ejection portion D is reduced, potentially degrading the image quality of the image formed by the inkjet printer 1. Therefore, in order to generate the drive signal Com having a waveform that accurately reproduces the waveform specified by the waveform designation signal dCom, the frequency of the modulation signal Ms must be set to 1 MHz or higher. In other words, in order to generate the drive signal Com having a waveform that accurately reproduces the waveform specified by the waveform designation signal dCom, the emission frequency of the self-excited oscillation of the drive signal generation circuit 4 and the drive frequencies of the transistors Tr1 and Tr2 must be set to 1 MHz or higher. Therefore, in the first embodiment, by setting the frequency of the modulation signal Ms to 1 MHz or higher, the frequencies of the gate signals SG1 and SG2 to 1 MHz or higher, and the drive frequencies of the transistors Tr1 and Tr2 to 1 MHz or higher, the waveform of the drive signal Com can be made to accurately reproduce the waveform specified by the waveform specifying signal dCom, thereby suppressing a decrease in the accuracy of ink ejection from the ejection portion D.

[0080] On the other hand, when the frequency of the modulation signal Ms increases, the switching losses in the transistors Tr1 and Tr2 increase. If the switching losses of the transistors Tr1 and Tr2 increase, the power consumption in the drive signal generation circuit 4 increases, and the heat generated in the drive signal generation circuit 4 increases. From the perspective of reducing the switching losses in the transistor Tr, the drive frequency of the transistor Tr is preferably 8 MHz or less, and more preferably 4 MHz or less. Therefore, in the first embodiment, by setting the frequency of the modulation signal Ms to 8 MHz or less, the frequencies of the gate signals SG1 and SG2 are set to 8 MHz or less, and the drive frequencies of the transistors Tr1 and Tr2 are set to 8 MHz or less. Thus, according to the first embodiment, it is possible to achieve both improved waveform accuracy of the drive signal Com and power saving of the drive signal generation circuit 4.

[0081] A.3. Structure and Operation of Liquid Dispensing Unit 3

[0082] Below, refer to Figures 5 to 7 , an example of the structure and operation of the liquid ejecting unit 3 is described.

[0083] Figure 5 It is a block diagram showing an example of the structure of the liquid ejection unit 3.

[0084] like Figure 5 As shown, the liquid ejection unit 3 includes a supply circuit 31 and a liquid ejection head 32. In addition, the liquid ejection unit 3 includes a wiring LC to which the drive signal Com is supplied from the drive signal generating unit 5.

[0085] like Figure 5 As shown, the supply circuit 31 includes M switches WS[1] to WS[M] corresponding one-to-one to the M ejection parts D[1] to D[M] and a connection state designation circuit 310 for designating the connection state of each switch.

[0086] The connection state designation circuit 310 generates a connection state designation signal QS[m] that designates on and off of the switch WS[m] based on the designation signal SI supplied from the control unit 2 , the latch signal LAT, and at least part of the change signal CH.

[0087] Based on the connection state designation signal QS[m], the switch WS[m] switches between conductive and non-conductive connection between the wiring LC and the upper electrode Zu[m] of the piezoelectric element PZ[m] provided in the ejection unit D[m]. In the first embodiment, the switch WS[m] is turned on when the connection state designation signal QS[m] is at a high level, and is turned off when it is at a low level. When the switch WS[m] is turned on, the drive signal Com supplied to the wiring LC is supplied to the upper electrode Zu[m] of the ejection unit D[m] as the supply drive signal Vin[m].

[0088] Figure 6 1 is a timing chart showing various signals such as the drive signal Com supplied to the liquid ejection unit 3 .

[0089] like Figure 6 As shown, when the inkjet printer 1 executes printing, one or more unit periods TP are set as the operation period of the inkjet printer 1. In the first embodiment, the inkjet printer 1 can drive each ejection unit D[m] for printing in each unit period TP.

[0090] like Figure 6 As shown, control unit 2 outputs latch signal LAT with pulse PLL. Consequently, control unit 2 defines unit period TP as the period from the rising edge of pulse PLL to the rising edge of the next pulse PLL. Furthermore, control unit 2 outputs change signal CH with pulse PLC during unit period TP. Control unit 2 then divides unit period TP into a drive period TQ1 from the rising edge of pulse PLL to the rising edge of pulse PLC, and a drive period TQ2 from the rising edge of pulse PLC to the rising edge of pulse PLL.

[0091] like Figure 6 As shown, the designation signal SI includes M individual designation signals Sd[1] to Sd[M] corresponding one-to-one to the M ejection units D[1] to D[M]. When the inkjet printer 1 performs printing, the individual designation signal Sd[m] specifies the driving method of the ejection unit D[m] in each unit period TP. Before each unit period TP, the control unit 2 synchronizes the designation signal SI including the M individual designation signals Sd[1] to Sd[M] with the clock signal CL and supplies the designation signal SI to the connection state designation circuit 310. Then, in the unit period TP, the connection state designation circuit 310 generates the connection state designation signal QS[m] based on the individual designation signal Sd[m].

[0092] In addition, in the first embodiment, in the unit period TP during which the printing process is performed, it is assumed that the ejection portion D[m] is capable of forming any one of a large dot consisting of ink having an ink amount ξ1, a medium dot consisting of ink having an ink amount ξ2 which is smaller than the ink amount ξ1, and a small dot consisting of ink having an ink amount ξ3 which is smaller than the ink amount ξ2.

[0093] Figure 7 This is an explanatory diagram for explaining an example of the individual designation signal Sd[m].

[0094] like Figure 7 As shown, in the first embodiment, the individual designation signal Sd[m] can take any one of four values ​​during the unit period TP for executing the printing process: a value of "1" for designating the ejection unit D[m] as a large dot forming ejection unit DP-1, a value of "2" for designating the ejection unit D[m] as a medium dot forming ejection unit DP-2, a value of "3" for designating the ejection unit D[m] as a small dot forming ejection unit DP-3, and a value of "4" for designating the ejection unit D[m] as a dot non-forming ejection unit DP-N.

[0095] Here, the large dot-forming ejection portion DP-1 refers to the ejection portion D that forms a large dot in the unit period TP. Furthermore, the medium dot-forming ejection portion DP-2 refers to the ejection portion D that forms a medium dot in the unit period TP. Furthermore, the small dot-forming ejection portion DP-3 refers to the ejection portion D that forms a small dot in the unit period TP. Furthermore, the dot-non-forming ejection portion DP-N refers to the ejection portion D that does not form a dot in the unit period TP.

[0096] Return instructions to Figure 6 .

[0097] like Figure 6 As shown, in the first embodiment, the driving signal Com has a waveform PA1 provided in the driving period TQ1 and a waveform PA2 provided in the driving period TQ2.

[0098] The waveform PA1 is a waveform that returns from the potential V0 via the potential VLA1, which is lower than the potential V0, and the potential VHA1, which is higher than the potential V0, to the potential V0. When the supply drive signal Vin[m] having the waveform PA1 is supplied to the discharge portion D[m], the waveform PA1 is determined so that ink corresponding to the ink amount φ1 is discharged from the discharge portion D[m]. Furthermore, the waveform PA2 is a waveform that returns from the potential V0 via the potential VLA2, which is lower than the potential V0, and the potential VHA2, which is higher than the potential V0, to the potential V0. When the supply drive signal Vin[m] having the waveform PA2 is supplied to the discharge portion D[m], the waveform PA2 is determined so that ink corresponding to the ink amount φ2 is discharged from the discharge portion D[m]. Furthermore, in the first embodiment, it is assumed that the ink amount ξ1 corresponds to the total amount of ink amounts φ1 and φ2, the ink amount ξ2 corresponds to the ink amount φ1, and the ink amount ξ3 corresponds to the ink amount φ2.

[0099] Furthermore, in the first embodiment, as an example, it is assumed that when the potential of the supply drive signal Vin[m] supplied to the discharge portion D[m] is high, the volume of the cavity CV included in the discharge portion D[m] decreases compared to when the potential is low. Therefore, when the discharge portion D[m] is driven by the supply drive signal Vin[m] having a waveform PA1, for example, the potential of the supply drive signal Vin[m] changes from a low potential to a high potential, causing the ink within the discharge portion D[m] to be discharged from the nozzle N.

[0100] like Figure 7 As shown, when the individual designation signal Sd[m] indicates a value of "1" designating discharge unit D[m] as the large-dot-forming discharge unit DP-1 during unit period TP, connection state designation circuit 310 sets connection state designation signal QS[m] to a high level during driving periods TQ1 and TQ2. In this case, switch WS[m] is turned on during driving periods TQ1 and TQ2. Consequently, discharge unit D[m] is driven by supply drive signal Vin[m] having waveforms PA1 and PA2 during unit period TP, discharging ink corresponding to the large-dot ink amount ξ1.

[0101] Furthermore, when the individual designation signal Sd[m] indicates a value of "2" designating the discharge unit D[m] as the midpoint-forming discharge unit DP-2 during the unit period TP, the connection state designation circuit 310 sets the connection state designation signal QS[m] to a high level during the driving period TQ1. In this case, the switch WS[m] is turned on during the driving period TQ1. Consequently, the discharge unit D[m] is driven by the supply drive signal Vin[m] having the waveform PA1 during the unit period TP, and discharges ink corresponding to the midpoint ink amount ξ2.

[0102] Furthermore, when the individual designation signal Sd[m] indicates a value of "3" designating the ejection unit D[m] as the small dot-forming ejection unit DP-3 during the unit period TP, the connection state designation circuit 310 sets the connection state designation signal QS[m] to a high level during the driving period TQ2. In this case, the switch WS[m] is turned on during the driving period TQ2. Consequently, the ejection unit D[m] is driven by the supply drive signal Vin[m] having the waveform PA2 during the unit period TP, ejecting ink corresponding to the small dot ink amount ξ3.

[0103] Furthermore, when the individual designation signal Sd[m] indicates a value of "4" designating the ejection unit D[m] as a dot-non-forming ejection unit DP-N during the unit period TP, the connection state designation circuit 310 sets the connection state designation signal QS[m] to a low level throughout the unit period TP. In this case, the switch WS[m] is open throughout the unit period TP. Consequently, the ejection unit D[m] is not driven by the supply drive signal Vin[m] during the unit period TP and does not eject ink.

[0104] A.4. Configuration of the drive signal generating unit 5

[0105] Below, refer to Figure 8 , the structure of the driving signal generating unit 5 is described.

[0106] Figure 8 1 is a cross-sectional view showing an example of the structure of the drive signal generating unit 5 when the drive signal generating unit 5 is cut along a plane whose normal direction is the X-axis direction, that is, a plane intersecting the transistor Tr. In the first embodiment, as an example, it is assumed that the transistors Tr1 and Tr2 have the same structure.

[0107] like Figure 8 As shown, the transistor Tr is provided on the substrate 51 included in the drive signal generating unit 5. Specifically, in the first embodiment, the substrate 51 is a flat plate-shaped member extending with the Z-axis direction as its normal direction. Assume that the substrate 51 has two surfaces with the Z-axis direction as its normal direction: a surface 511 facing the Z1 direction and a surface 512 facing the Z2 direction. Furthermore, in the first embodiment, it is assumed that the transistor Tr is provided on the surface 512 of the substrate 51.

[0108] The transistor Tr includes a chip body portion 60 , a gate electrode 61 g , a source electrode 61 s , and a drain electrode 61 d .

[0109] The chip body 60 is a so-called chip and has a substantially rectangular parallelepiped shape. In the first embodiment, the chip body 60 has a surface 601 facing the Z1 direction and a surface 602 facing the Z2 direction as two surfaces with the Z-axis direction as the normal direction.

[0110] In the first embodiment, as an example, a case is assumed where the source electrode 61 s and the drain electrode 61 d are provided on the surface 601 of the chip body 60 , and the gate electrode 61 g is provided on the surface 602 .

[0111] A plurality of gate connection terminals 62g are provided on the surface 512 of the substrate 51 so as to correspond to the plurality of transistors Tr included in the drive signal generating unit 5. The gate electrode 61g is electrically connected to the gate connection terminal 62g provided corresponding to the transistor Tr having the gate electrode 61g. In the first embodiment, as an example, a case where the gate electrode 61g is electrically connected to the gate connection terminal 62g via the wire 64 is assumed.

[0112] Each gate connection terminal 62g is electrically connected to the integrated circuit 40. Specifically, the gate connection terminal 62g provided corresponding to the transistor Tr1 is electrically connected to the terminal TnG1 of the integrated circuit 40 via the resistor RG1. In addition, the gate connection terminal 62g provided corresponding to the transistor Tr2 is electrically connected to the terminal TnG2 of the integrated circuit 40 via the resistor RG2.

[0113] A plurality of source connection terminals 62s are provided on the surface 512 of the substrate 51 so as to correspond to the plurality of transistors Tr included in the drive signal generating unit 5. The source electrode 61s is electrically connected to the source connection terminal 62s provided corresponding to the transistor Tr having the source electrode 61s. In the first embodiment, as an example, a case where the source electrode 61s is directly connected to the source connection terminal 62s is assumed.

[0114] Each source connection terminal 62s is electrically connected to a node Nd or a power supply line set to a reference potential VLL. Specifically, the source connection terminal 62s provided for transistor Tr1 is electrically connected to the node Nd. Furthermore, the source connection terminal 62s provided for transistor Tr2 is electrically connected to a power supply line set to a reference potential VLL.

[0115] A plurality of drain connection terminals 62d are provided on the surface 512 of the substrate 51 so as to correspond to the plurality of transistors Tr included in the drive signal generating unit 5. The drain electrode 61d is electrically connected to the drain connection terminal 62d provided corresponding to the transistor Tr having the drain electrode 61d. In the first embodiment, as an example, a case where the drain electrode 61d is directly connected to the drain connection terminal 62d is assumed.

[0116] Each drain connection terminal 62d is electrically connected to a node Nd or a power supply line set to a power supply potential VHH. Specifically, the drain connection terminal 62d provided for transistor Tr1 is electrically connected to a power supply line set to a power supply potential VHH. Furthermore, the drain connection terminal 62d provided for transistor Tr2 is electrically connected to the node Nd.

[0117] The heat sink 52 is mounted on the surface 511 of the substrate 51. The heat sink 52 includes a main body portion 520 and a coating portion 521.

[0118] The main body portion 520 is formed of copper or aluminum, and includes a base portion 5201 , a heat sink 5202 , and a heat sink 5203 .

[0119] The base portion 5201 extends on a plane PL1 whose normal direction is the Z-axis. The heat sink 5202 is connected to a connection portion PY1 of the base portion 5201 and extends on a plane PL2 whose normal direction is the Y-axis. The heat sink 5203 is connected to a connection portion PY2 of the base portion 5201, located in the Y1 direction as viewed from the connection portion PY1, and extends on a plane PL3 whose normal direction is the Y-axis. In other words, in the first embodiment, the heat sink 52 includes two heat sinks.

[0120] In addition, in the first embodiment, the base portion 5201 is an example of a “first plate-like portion”, the heat sink 5202 is an example of a “second plate-like portion”, the heat sink 5203 is an example of a “third plate-like portion”, the plane PL1 is an example of a “first plane”, the plane PL2 is an example of a “second plane”, the plane PL3 is an example of a “third plane”, the connecting portion PY1 is an example of a “first portion”, and the connecting portion PY2 is an example of a “second portion”.

[0121] The coating portion 521 is made of graphene and coats the main body portion 520. Specifically, the coating portion 521 coats at least the entire surfaces of the heat sink 5202 and the heat sink 5203 of the main body portion 520 and the surface of the base portion 5201 in the Z1 direction.

[0122] Here, graphene is a sheet-like substance composed of carbon atoms. Hereinafter, a sheet-like substance with a thickness of one carbon atom in graphene is referred to as a graphene sheet. In the first embodiment, it is assumed that the coating portion 521 is composed of multiple layers of graphene sheets.

[0123] A.5. Existing Examples

[0124] Below, in reference Figure 9 as well as Figure 10The effects of the drive signal generating unit 5 according to the first embodiment will be described after describing the drive signal generating unit 5W according to the conventional example.

[0125] Figure 9 1 is a cross-sectional view showing an example of the structure of the drive signal generating unit 5W when the drive signal generating unit 5W is cut along a plane having the X-axis direction as a normal direction, that is, a plane intersecting the transistor Tr.

[0126] like Figure 9 As shown, the drive signal generating unit 5W has the same structure as the drive signal generating unit 5 involved in the first embodiment, except that it includes a heat sink 52W instead of the heat sink 52. The heat sink 52W differs from the heat sink 52 involved in the first embodiment in that it includes a main body portion 520W instead of the main body portion 520 and does not include the coating portion 521. The main body portion 520W is formed of copper or aluminum in the same manner as the main body portion 520. The main body portion 520W is configured in the same manner as the main body portion 520 involved in the first embodiment, except that it includes three or more heat sinks 520F instead of the heat sinks 5202 and the heat sinks 5203. Specifically, the main body portion 520W includes ten or more heat sinks 520F. Each heat sink 520F is a flat plate-shaped component extending with the Z-axis direction as its normal direction.

[0127] Figure 10 1 and 2 are diagrams showing the actual measurement results of the temperatures of the drive signal generating unit 5 and the drive signal generating unit 5W and the actual measurement results of the weights of the heat sink 52 and the heat sink 52W.

[0128] like Figure 10 As shown, when the drive signal generating unit 5 according to the first embodiment has a 10W heat source, the temperature of the drive signal generating unit 5 having the heat sink 52 is "85 degrees." On the other hand, when the drive signal generating unit 5W according to the conventional example has a 10W heat source, the temperature of the drive signal generating unit 5W having the heat sink 52W is "86 degrees." Thus, the temperature of the drive signal generating unit 5 having the heat sink 52 is substantially the same as the temperature of the drive signal generating unit 5 having the heat sink 52W. Here, "substantially the same" means not only completely identical but also includes situations where they are considered to be the same if errors are taken into account. For example, situations where the design is the same but there are differences due to manufacturing errors, and situations where the specifications are the same but there are differences due to errors caused by interference, etc. In the first embodiment, "substantially the same" is a concept that includes situations where errors of about 10% are considered to be the same.

[0129] like Figure 10As shown, the heat sink 52 according to the first embodiment has 2 fins and weighs 35 g. On the other hand, the heat sink 52W according to the conventional example has 16 fins and weighs 150 g.

[0130] Thus, the radiator 52 according to the first embodiment limits the number of fins to two, thereby achieving a significant weight reduction compared to the radiator 52W having ten or more fins. Specifically, the radiator 52 according to the first embodiment can reduce weight by approximately 25% compared to the radiator 52W according to the conventional example. Therefore, according to the first 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 compared to the case where the drive signal generation unit 5W according to the conventional example is mounted on the carriage 110 and moved. In other words, compared to the case where the drive signal generation unit 5W according to the conventional example is mounted on the carriage 110, the drive signal generation unit 5 according to the first embodiment can extend the life of the carriage transport motor 91 and reduce the amount of power required to drive the carriage transport motor 91.

[0131] Furthermore, the heat sink 52 according to the first embodiment has a surface coated with graphene, resulting in superior heat dissipation compared to the conventional heat sink 52W, which is not coated with graphene. Consequently, despite significantly reducing the number of heat sinks compared to the conventional heat sink 52W, the heat sink 52 according to the first embodiment can maintain the temperature of the drive signal generating unit 5 at a level comparable to that of the drive signal generating unit 5W equipped with the heat sink 52W. In other words, the heat sink 52 according to the first embodiment easily achieves both weight reduction and improved heat dissipation compared to the conventional heat sink 52W.

[0132] Furthermore, since the heat sink 52 according to the first embodiment has a surface coated with graphene, the possibility of corrosion of the heat sink 52 by ink mist is reduced compared to the conventional heat sink 52W, which is not coated with graphene. Therefore, compared to the conventional heat sink 52W, the heat sink 52 according to the first embodiment can suppress the degradation of heat dissipation performance caused by corrosion of the heat sink 52 and maintain high heat dissipation performance for a long period of time.

[0133] B. Second embodiment

[0134] Below, refer to Figure 11 as well as Figure 12In the following, the inkjet printer 1 according to the second embodiment is described. In the following embodiments, elements having the same functions and effects as those in the first embodiment are assigned the same reference numerals as those in the first embodiment, and detailed descriptions thereof are omitted as appropriate.

[0135] Figure 11 : is a cross-sectional view showing an example of the structure of the drive signal generating unit 5B included in the inkjet printer 1 according to the second embodiment. Specifically, Figure 11 : is a cross-sectional view showing an example of the structure of the drive signal generating unit 5B when the drive signal generating unit 5B is cut through a plane whose normal direction is the X-axis direction, that is, a plane intersecting the transistor Tr-B. The inkjet printer 1 according to the second embodiment is configured similarly to the inkjet printer 1 according to the first embodiment, except that the drive signal generating unit 5B is provided instead of the drive signal generating unit 5. In the second embodiment, Figure 4 The transistor Tr1 and the transistor Tr2 shown are collectively referred to as a transistor Tr-B.

[0136] like Figure 11 As shown, the drive signal generating unit 5B has the same configuration as the drive signal generating unit 5 according to the first embodiment, except that it includes a transistor Tr-B instead of the transistor Tr, a mold member 55 , and a clip 63 .

[0137] The transistor Tr-B has the same configuration as the transistor Tr according to the first embodiment, except that a source electrode 61 s is provided on the surface 601 of the chip body 60 , and a gate electrode 61 g and a drain electrode 61 d are provided on the surface 602 .

[0138] A plurality of gate connection terminals 62g are provided on the surface 512 of the substrate 51 so as to correspond to the plurality of transistors Tr-B included in the drive signal generating unit 5B. The gate electrode 61g is electrically connected to the gate connection terminal 62g provided corresponding to the transistor Tr-B having the gate electrode 61g. In the second embodiment, as an example, a case where the gate electrode 61g is electrically connected to the gate connection terminal 62g via the wire 64 is assumed.

[0139] A plurality of source connection terminals 62s are provided on the surface 512 of the substrate 51, corresponding to the plurality of transistors Tr-B included in the drive signal generating unit 5B. The source electrode 61s is electrically connected to the source connection terminal 62s of the transistor Tr-B corresponding to the source electrode 61s. In the second embodiment, as an example, a case where the source electrode 61s is directly connected to the source connection terminal 62s is assumed.

[0140] A plurality of drain connection terminals 62d are provided on the surface 512 of the substrate 51, corresponding to the plurality of transistors Tr-B included in the drive signal generating unit 5B. The drain electrode 61d is electrically connected to the drain connection terminal 62d of the transistor Tr-B corresponding to the drain electrode 61d. In the second embodiment, as an example, a case is assumed where the drain electrode 61d is electrically connected to the drain connection terminal 62d via the clip 63.

[0141] Here, the clip 63 is a component formed of a metal such as copper. That is, in the second embodiment, it is assumed that the transistor Tr-B (ie, the transistor Tr1 and the transistor Tr2) has a Cu clip structure.

[0142] The mold member 55 is formed of an insulating material such as resin. The mold member 55 is provided to seal the transistor Tr-B on the surface 512 of the substrate 51. In the second embodiment, as an example, a case is assumed where the mold member 55 is provided to cover the transistor Tr-B, the clip 63, and the wire 64 on the surface 512 of the substrate 51.

[0143] Furthermore, the second embodiment assumes that a reaction liquid can be ejected from a portion of the multiple ejection units D provided in the liquid ejection unit 3. Here, the reaction liquid is a liquid used to fix the ink to the recording paper PP. In the second embodiment, the inkjet printer 1 ejects ink from one ejection unit D provided in the liquid ejection unit 3 onto the recording paper PP. Thereafter, the reaction liquid is ejected from the remaining ejection units D provided in the liquid ejection unit 3 onto the recording paper PP, thereby fixing the ink adhered to the recording paper PP. Furthermore, in the second embodiment, the reaction liquid is another example of a "liquid."

[0144] Figure 12 This is a diagram showing an example of the composition and physical properties of the reaction solution according to the second embodiment.

[0145] like Figure 12 As shown, the reaction solution contained 19% by mass of calcium nitrate tetrahydrate as a coagulant and 0.6% by mass of a silicone surfactant as a surfactant. Furthermore, the solvents included 3% by mass of 1,2-hexanediol, 15% by mass of propylene glycol, 0.1% by mass of tripropanolamine, 0.1% by mass of 0.1M acetic acid, and water as the remainder, with the total mass being 100% by mass. Furthermore, the reaction solution was adjusted to a coagulant concentration of 0.8 (mol / L), a pH of 3, a viscosity of 4 (mPa·s at 20°C), and a surface tension of 25 (mN / m).

[0146] In addition, as the reaction liquid, a liquid having a pH of "3 or less" may be used. In addition, as the reaction liquid, "Reaction Liquid H7" disclosed in Japanese Patent Application Laid-Open No. 2016-199001 by the present applicant may be used.

[0147] As described above, in the second embodiment, the transistor Tr-B has a Cu clip structure. Therefore, in the second embodiment, the areas of the drain electrode 61d and drain connection terminal 62d, as well as the source electrode 61s and source connection terminal 62s, can be increased compared to a method not employing a Cu clip structure. Consequently, in the second embodiment, higher heat dissipation from the transistor Tr-B can be ensured compared to a method not employing a Cu clip structure.

[0148] Furthermore, in the second embodiment, the transistor Tr-B employs a Cu clip structure, thereby improving the shock resistance of the transistor Tr-B compared to a method in which the drain electrode 61d and the drain connection terminal 62d are connected via a wire 64 without employing a Cu clip structure. Consequently, in the second embodiment, even in situations where there is a high probability of shock being applied to the drive signal generating unit 5B, such as when the drive signal generating unit 5B including the transistor Tr-B is mounted on the carriage 110, the life of the drive signal generating unit 5B can be extended compared to a method in which the Cu clip structure is not employed.

[0149] In addition, in the second embodiment, a reaction liquid with a pH of 3 or less is ejected from the liquid ejection unit 3. Moreover, if a low-pH liquid with a pH of 3 or less adheres to the metal in the inkjet printer 1, there is a high possibility of corroding the metal. In contrast, in the second embodiment, the transistor Tr-B is covered by the molded part 55. Therefore, compared with a method in which the drive signal generating unit 5B does not include the molded part 55, the adhesion of ink and reaction liquid to the transistor Tr-B can be reduced. Therefore, according to the second embodiment, compared with a method in which the drive signal generating unit 5B does not include the molded part 55, the corrosion of metal such as the wiring and terminals of the transistor Tr-B can be suppressed, thereby achieving a longer life of the transistor Tr-B.

[0150] In addition, in the second embodiment, the transistor Tr-B is illustrated as having a source electrode 61s on the surface 601 in the chip body 60, and a gate electrode 61g and a drain electrode 61d on the surface 602, but the present invention is not limited to such a method. For example, the transistor Tr-B may also have a drain electrode 61d on the surface 601 in the chip body 60, and a gate electrode 61g and a source electrode 61s on the surface 602. In this case, the drain electrode 61d may also be directly connected to the drain connection terminal 62d. In this case, the source electrode 61s may also be electrically connected to the source connection terminal 62s via the clip 63. In this case, the gate electrode 61g may also be electrically connected to the gate connection terminal 62g via the wire 64.

[0151] In the second embodiment, the gate electrode 61g is electrically connected to the gate connection terminal 62g via the wire 64, but the present invention is not limited to this method. For example, the gate electrode 61g may be electrically connected to the gate connection terminal 62g via a conductive clip such as the clip 63.

[0152] C. Third embodiment

[0153] Below, refer to Figure 13 , an inkjet printer 1 according to a third embodiment will be described. In the following embodiments, elements having the same functions and effects as those in the first or second embodiment will be assigned the same reference numerals as those in the first or second embodiment, and detailed descriptions thereof will be omitted as appropriate.

[0154] Figure 13 : is a cross-sectional view showing an example of the structure of the drive signal generating unit 5C included in the inkjet printer 1 according to the third embodiment. Specifically, Figure 13 : is a cross-sectional view showing an example of the structure of the drive signal generating unit 5C when the drive signal generating unit 5C is cut through a plane whose normal direction is the X-axis direction, that is, a plane intersecting the transistor Tr-B. In addition, the inkjet printer 1 according to the third embodiment is configured in the same manner as the inkjet printer 1 according to the second embodiment, except that the drive signal generating unit 5C is provided instead of the drive signal generating unit 5. In addition, in the third embodiment, the drive signal generating unit 5C is replaced by the drive signal generating unit 5C. Figure 4 The transistor Tr1 and the transistor Tr2 shown are collectively referred to as a transistor Tr-B.

[0155] like Figure 13As shown, the drive signal generating unit 5C has the same configuration as the drive signal generating unit 5B according to the second embodiment, except that it includes a mold member 55C instead of the mold member 55 and a heat sink 56 .

[0156] As described above, transistor Tr-B has a source electrode 61s provided on surface 601 of chip body 60, and a gate electrode 61g and a drain electrode 61d provided on surface 602. Gate electrode 61g is electrically connected to gate connection terminal 62g via wire 64. Source electrode 61s is directly connected to source connection terminal 62s. Drain electrode 61d is electrically connected to drain connection terminal 62d via clip 63. That is, in the third embodiment, as in the second embodiment, it is assumed that transistor Tr-B (i.e., transistor Tr1 and transistor Tr2) has a Cu clip structure.

[0157] The mold member 55C is formed of an insulating material such as resin. The mold member 55C is provided to seal the transistor Tr-B on the surface 512 of the substrate 51. In the second embodiment, as an example, a case is assumed where the mold member 55 is provided to cover the transistor Tr-B and the wire 64 on the surface 512 of the substrate 51, with the surface of the clip 63 in the Z2 direction exposed.

[0158] The heat sink 56 is provided over the surface of the clip 63 in the Z2 direction and the surface of the molded member 55C in the Z2 direction. The heat sink 56 includes a main body portion 560 and a coating portion 561.

[0159] The main body 560 is formed of copper or aluminum and comprises a base portion 5601 extending in a flat plate shape with the Z-axis direction as its normal direction, a heat sink 5602 extending in a flat plate shape with the Y-axis direction as its normal direction, and a heat sink 5603 extending in a flat plate shape with the Y-axis direction as its normal direction. That is, in the third embodiment, the heat sink 56 has two heat sinks, similar to the heat sink 52.

[0160] The coating portion 561 is composed of graphene and coats the main body portion 560. Specifically, the coating portion 561 coats at least the entire surfaces of the heat sink 5602 and the heat sink 5603 of the main body portion 560, and the surface in the Z2 direction of the base portion 5601. In the third embodiment, the coating portion 561 is assumed to be composed of a multilayer graphene sheet.

[0161] As described above, according to the third embodiment, the drive signal generating unit 5C includes the heat sink 56. Therefore, in addition to heat dissipation in the Z1 direction from the heat sink 52, heat dissipation in the Z2 direction from the heat sink 56 is also possible. Therefore, according to the third embodiment, compared with a method that does not consider heat dissipation in the Z2 direction, high heat dissipation performance can be ensured in the drive signal generating unit 5C.

[0162] Furthermore, according to the third embodiment, the transistor Tr-B is covered by the molded member 55C. This reduces the adhesion of ink and reaction liquid to the transistor Tr-B compared to an embodiment in which the drive signal generating unit 5C does not include the molded member 55C. Therefore, according to the third embodiment, compared to an embodiment in which the drive signal generating unit 5C does not include the molded member 55C, corrosion of metal such as the wiring and terminals of the transistor Tr-B can be suppressed, thereby extending the life of the transistor Tr-B. Furthermore, in the third embodiment, as in the second embodiment, a reaction liquid having a pH of 3 or less can be ejected from the liquid ejection unit 3.

[0163] Furthermore, according to the third embodiment, the transistor Tr-B has a Cu clip structure. This allows for larger areas of the drain electrode 61d and drain connection terminal 62d, as well as the source electrode 61s and source connection terminal 62s, compared to a method without a Cu clip structure. Consequently, in the third embodiment, higher heat dissipation from the transistor Tr-B can be ensured compared to a method without a Cu clip structure.

[0164] In addition, the heat sink 56 involved in the third embodiment has a surface coated with graphene, so compared with the method of using the heat sink 52W involved in the existing example that is not coated with graphene as the heat sink 56, it can exhibit better performance from the perspective of lightweight, heat dissipation and corrosion resistance.

[0165] In addition, in the third embodiment, an example is given in which the transistor Tr-B is provided with a source electrode 61s on the surface 601 in the chip body 60, and a gate electrode 61g and a drain electrode 61d are provided on the surface 602, but the present invention is not limited to such an example. For example, the transistor Tr-B may also be provided with a drain electrode 61d on the surface 601 in the chip body 60, and a gate electrode 61g and a source electrode 61s on the surface 602. In this case, the drain electrode 61d may also be directly connected to the drain connection terminal 62d. In this case, the source electrode 61s may also be electrically connected to the source connection terminal 62s via the clip 63. In this case, the gate electrode 61g may also be electrically connected to the gate connection terminal 62g via the wire 64.

[0166] In the third embodiment, the gate electrode 61g is electrically connected to the gate connection terminal 62g via the wire 64, but the present invention is not limited to this method. For example, the gate electrode 61g may be electrically connected to the gate connection terminal 62g via a conductive clip such as the clip 63.

[0167] Furthermore, in the third embodiment, the drive signal generating unit 5C is illustrated as including the graphene-coated heat sink 52 and the heat sink 56. However, the present invention is not limited to this embodiment. The drive signal generating unit 5C may include a heat sink 52W on the surface 511 of the substrate 51 instead of the heat sink 52, or may include a heat sink 52W on the surface of the clip 63 and the mold member 55C in the Z2 direction instead of the heat sink 56.

[0168] D. Modification

[0169] Each of the above embodiments can be modified in various ways. Specific modifications are exemplified below. Two or more embodiments arbitrarily selected from the following examples can be appropriately combined within the scope of mutual non-contradiction. In addition, in the modifications exemplified below, for elements having the same effects and functions as those in the embodiment, the same reference numerals as those in the above description are used, and detailed descriptions thereof are appropriately omitted.

[0170] D.1. Modification 1

[0171] In the first to third embodiments, the driving signal generating unit 5 and the liquid ejecting unit 3 are separate bodies, but the present invention is not limited to this embodiment. The driving signal generating unit 5 may be built into the liquid ejecting unit 3 .

[0172] Figure 14 This is a functional block diagram showing an example of the configuration of an inkjet printer 1D according to Modification 1.

[0173] like Figure 14 As shown, the inkjet printer 1D is configured in the same manner as the inkjet printer 1 according to the first embodiment, except that it includes a liquid ejection unit 3D instead of the liquid ejection unit 3. The liquid ejection unit 3D is configured in the same manner as the liquid ejection unit 3 according to the first embodiment, except that it includes a drive signal generating unit 5. Figure 14 In the embodiment, the liquid ejection unit 3D is shown as including the drive signal generating unit 5, but the present invention is not limited to this embodiment. The liquid ejection unit 3D may include the drive signal generating unit 5B instead of the drive signal generating unit 5, or may include the drive signal generating unit 5C instead of the drive signal generating unit 5.

[0174] D.2. Modification 2

[0175] In the first to third embodiments and Modification 1, the mold member 55 or the mold member 55C is described as sealing one transistor Tr or one transistor Tr-B. However, the present invention is not limited to this method. The mold member 55 or the mold member 55C may also seal two or more transistors Tr or two or more transistors Tr-B.

[0176] For example, Figure 15 As shown, the molded part 55 can also seal the transistor Tr1 and the transistor Tr2 into one package. Figure 16 As shown, the mold member 55C may also seal the transistor Tr1 and the transistor Tr2 into one package.

[0177] D.3. Modification 3

[0178] In the first to third embodiments and Modifications 1 and 2 described above, it is assumed that the inkjet printer 1 includes four liquid ejection units 3 and four drive signal generation units 5. However, the present invention is not limited to this configuration. The inkjet printer 1 may include one or more and three or fewer liquid ejection units 3 and one or more and three or fewer drive signal generation units 5, or may include five or more liquid ejection units 3 and five or more drive signal generation units 5.

[0179] E. Notes

[0180] In order to facilitate understanding of each embodiment, the following descriptions are supplemented with reference numerals of the accompanying drawings in parentheses for convenience, but the present invention is not limited to the embodiments shown in the drawings.

[0181] E.1. Note 1

[0182] Hereinafter, the inkjet printer 1 according to Supplementary Note 1 will be described.

[0183] Note 1-1

[0184] The inkjet printer 1 involved in Note 1-1 is characterized in that it comprises: a liquid ejection unit 3, which has a plurality of piezoelectric elements PZ[m] driven by a drive signal Com, and ejects ink according to the drive of the plurality of piezoelectric elements PZ[m]; and a drive signal generating unit 5, which generates a drive signal Com, and the drive signal generating unit 5 comprises: a substrate 51; a drive signal generating circuit 4, which is arranged on the substrate 51 and generates the drive signal Com; and a heat sink 52, which is fixed to the substrate 51, and the heat sink 52 has a main body 520 formed of copper or aluminum, and the main body 520 is coated with graphene.

[0185] According to Supplementary Note 1-1, since the heat sink 52 is coated with graphene, the heat dissipation performance of the heat sink 52 can be improved compared to a case where the heat sink 52 is not coated with graphene. Furthermore, according to Supplementary Note 1-1, since the heat sink 52 is coated with graphene, the possibility of corrosion of the main body 520 of the heat sink 52 can be reduced compared to a case where the heat sink 52 is not coated with graphene, thereby suppressing the reduction in the heat dissipation performance of the heat sink 52 that accompanies corrosion of the heat sink 52.

[0186] Notes 1-2

[0187] The inkjet printer 1 according to Supplementary Note 1-2 is the inkjet printer 1 according to Supplementary Note 1-1, and is characterized in that a portion of the ink ejected from the liquid ejection unit 3 is atomized.

[0188] According to Supplementary Note 1-2, since the heat sink 52 is coated with graphene, the possibility of the main body 520 of the heat sink 52 being corroded by mist can be reduced compared to a configuration in which the heat sink 52 is not coated with graphene.

[0189] Notes 1-3

[0190] The inkjet printer 1 according to Supplementary Note 1-3 is the inkjet printer 1 according to Supplementary Note 1-1 or Supplementary Note 1-2, and is characterized in that the main body portion 520 is coated with multi-layer graphene.

[0191] According to Supplementary Notes 1-3, the heat sink 52 is coated with multi-layer graphene, and thus the possibility of the main body 520 of the heat sink 52 being corroded by mist can be reduced compared to a case where the heat sink 52 is not coated with a single layer of graphene.

[0192] Notes 1-4

[0193] The inkjet printer 1 involved in Note 1-4 is the inkjet printer 1 involved in Notes 1-1 to 1-3, and is characterized in that the main body 520 is composed of a base 5201, a heat sink 5202 and a heat sink 5203, the base 5201 extends on a plane PL1 with the Z1 direction as the normal direction, the heat sink 5202 is connected to the connecting part PY1 of the base 5201, and extends on a plane PL2 with the Y1 direction intersecting the Z1 direction as the normal direction, and the heat sink 5203 is connected to the connecting part PY2 of the base 5201 and extends on a plane PL3 with the Y1 direction as the normal direction.

[0194] In addition, in Supplementary Note 1, the Z1 direction is an example of the “first direction”, and the Y1 direction is an example of the “second direction”.

[0195] In Supplementary Notes 1-4, heat sink 52 has a simple shape with two heat sinks, heat sink 5202 and heat sink 5203. Therefore, compared to heat sink 52W having multiple heat sinks, heat sink 52 can be made lighter. Furthermore, in Supplementary Notes 1-4, heat sink 52 is coated with graphene, ensuring high heat dissipation within heat sink 52. In other words, according to Supplementary Notes 1-4, both light weight and high heat dissipation within heat sink 52 can be achieved.

[0196] Notes 1-5

[0197] The inkjet printer 1 involved in Note 1-5 is the inkjet printer 1 involved in Notes 1-1 to 1-4, and is characterized in that it comprises: a slide 110, which carries a liquid ejection unit 3 and a drive signal generating unit 5, and moves on the recording paper PP on which ink is ejected by the liquid ejection unit 3; and a slide conveying motor 91, which is used to move the slide 110, and the liquid ejection unit 3 ejects ink when the slide 110 moves.

[0198] According to Supplementary Note 1-5, the carriage 110 is equipped with the drive signal generating unit 5 including the heat sink 52 . Therefore, the load applied to the carriage transport motor 91 can be reduced compared to a configuration in which the drive signal generating unit 5W including the heat sink 52W is installed.

[0199] E.2. Note 2

[0200] Hereinafter, the inkjet printer 1 according to Supplementary Note 2 will be described.

[0201] Appendix 2-1

[0202] The inkjet printer 1 involved in Note 2-1 is characterized in that it comprises: a liquid ejection unit 3, which has a piezoelectric element PZ[m] driven by a drive signal Com, and ejects ink according to the drive of the piezoelectric element PZ[m]; and a drive signal generating unit 5B, which generates a drive signal Com, and the drive signal generating unit 5B comprises: an integrated circuit 40, which generates a gate signal SG1 and a gate signal SG2; a transistor Tr1, to which the gate signal SG1 is input; a transistor Tr2, to which the gate signal SG2 is input; an inductor element L0, one end of which is electrically connected to the transistor Tr1 and the transistor Tr2, and the other end of which is electrically connected to the output terminal Tn-out for outputting the drive signal Com; a substrate 51, on which the integrated circuit 40, the transistor Tr1, the transistor Tr2 and the inductor element L0 are mounted; and a molded component 55, which covers the transistor Tr1 on the substrate 51, and the transistor Tr1 has a Cu clamp structure.

[0203] According to Supplementary Note 2-1, the transistor Tr1 has a Cu-clip structure. Therefore, heat can be dissipated from the transistor Tr1 not only from the substrate 51 side but also from the side opposite to the substrate 51. Therefore, according to Supplementary Note 2-1, compared to a configuration in which the transistor Tr1 does not have a Cu-clip structure, heat dissipation from the transistor Tr1 can be improved, and the temperature of the transistor Tr1 can be suppressed. Furthermore, according to Supplementary Note 2-1, the drive signal generating unit 5B includes a mold member 55 covering the transistor Tr1. Therefore, compared to a configuration in which the mold member 55 is not included, the possibility of failure of the transistor Tr1 due to adhesion of ink to the transistor Tr1 can be reduced.

[0204] Note 2-2

[0205] The inkjet printer 1 according to Supplementary Note 2-2 is the inkjet printer 1 according to Supplementary Note 2-1, characterized in that the pH of the liquid ejected from the liquid ejection unit 3 is 3 or less.

[0206] According to Supplementary Note 2-2, the drive signal generating unit 5B includes the mold member 55 covering the transistor Tr1. Therefore, even in a situation where metal corrosion is likely to occur in the inkjet printer 1 due to the discharge of liquid with a pH of 3 or less from the liquid discharge unit 3, the possibility of corrosion of the transistor Tr1 can be reduced.

[0207] Notes 2-3

[0208] The inkjet printer 1 involved in Note 2-3 is the inkjet printer 1 involved in Note 2-1 or Note 2-2, and is characterized in that it comprises: a slide 110, which carries a liquid ejection unit 3 and a drive signal generating unit 5B, and moves on the recording paper PP on which ink is ejected by the liquid ejection unit 3; and a slide conveying motor 91, which is used to move the slide 110, and the liquid ejection unit 3 ejects ink when the slide 110 moves.

[0209] According to Supplementary Note 2-3, the transistor Tr1 has a Cu clip structure. This improves the shock resistance of the drive signal generating unit 5B including the transistor Tr1, compared to a configuration in which the transistor Tr1 is connected to the substrate 51 via a wire or the like. Therefore, according to Supplementary Note 2-3, even in situations where the drive signal generating unit 5B including the transistor Tr1 is mounted on the carriage 110 and there is a high probability of shock being applied to the drive signal generating unit 5B, the life of the drive signal generating unit 5B can be extended.

[0210] Notes 2-4

[0211] The inkjet printer 1 involved in Note 2-4 is the inkjet printer 1 involved in Notes 2-1 to 2-3, and is characterized in that the transistor Tr1 has: a chip main body 60; a drain electrode 61d, which is arranged on a surface 601 facing the substrate 51 among the multiple surfaces of the chip main body 60; and a source electrode 61s, which is arranged on a surface 602 opposite to the surface 601 among the multiple surfaces of the chip main body 60, the drain electrode 61d is connected to a drain connection terminal 62d provided on the substrate 51, and the source electrode 61s is connected to a conductive clip 63, and the clip 63 is connected to a source connection terminal 62s provided on the substrate 51.

[0212] In Supplementary Note 2, surface 601 is an example of the “first surface”, and surface 602 is an example of the “second surface”.

[0213] According to Note 2-4, the heat generated in the source electrode 61s and the drain electrode 61d of the transistor Tr1, which generate a lot of heat, is dissipated from the two surfaces 601 and 602 of the chip main body 60. Therefore, compared with the method of dissipating heat from a single surface of the chip main body 60, the heat dissipation performance of the transistor Tr1 can be improved.

[0214] Notes 2-5

[0215] The inkjet printer 1 involved in Note 2-5 is the inkjet printer 1 involved in Notes 2-1 to 2-3, and is characterized in that the transistor Tr1 has: a chip main body 60; a source electrode 61s, which is arranged on a surface 601 facing the substrate 51 among the multiple surfaces of the chip main body 60; and a drain electrode 61d, which is arranged on a surface 602 opposite to the surface 601 among the multiple surfaces of the chip main body 60, the source electrode 61s is connected to a source connection terminal 62s provided on the substrate 51, and the drain electrode 61d is connected to a conductive clip 63, and the clip 63 is connected to a drain connection terminal 62d provided on the substrate 51.

[0216] According to Note 2-5, the heat generated in the source electrode 61s and the drain electrode 61d of the transistor Tr1, which generate a lot of heat, is dissipated from the two surfaces 601 and 602 of the chip main body 60. Therefore, compared with the method of dissipating heat from a single surface of the chip main body 60, the heat dissipation performance of the transistor Tr1 can be improved.

[0217] Notes 2-6

[0218] The inkjet printer 1 according to Supplementary Note 2-6 is the inkjet printer 1 according to Supplementary Note 2-1 to Supplementary Note 2-5, wherein the gate signal SG1 is a signal for designating on / off switching of the transistor Tr1 and has a frequency of 1 MHz to 8 MHz.

[0219] According to Supplementary Note 2-6, it is possible to achieve both improvement in the accuracy of the waveform of the drive signal Com generated in the drive signal generating unit 5B including the transistor Tr1 and reduction in the switching loss in the transistor Tr1.

[0220] Notes 2-7

[0221] The inkjet printer 1 according to Supplementary Note 2-7 is the inkjet printer 1 according to Supplementary Note 2-1 to Supplementary Note 2-6, and is characterized in that the mold member 55 covers the transistor Tr1 and the transistor Tr2 on the substrate 51 .

[0222] According to Supplementary Note 2-7, the two transistors Tr1 and Tr2 are packaged as a single component. This reduces the component constant and the mounting area of ​​the transistors Tr1 and Tr2 compared to a system in which the transistors Tr1 and Tr2 are separate components. Therefore, according to Supplementary Note 2-7, the drive signal generating unit 5B can be made smaller and lighter.

[0223] E.3. Note 3

[0224] Hereinafter, the inkjet printer 1 according to Supplementary Note 3 will be described.

[0225] Note 3-1

[0226] The inkjet printer 1 involved in Note 3-1 is characterized in that it comprises: a liquid ejection unit 3, which has a piezoelectric element PZ[m] driven by a drive signal Com, and ejects ink according to the drive of the piezoelectric element PZ[m]; and a drive signal generating unit 5C, which generates a drive signal Com, and the drive signal generating unit 5C comprises: an integrated circuit 40, which generates a gate signal SG1 and a gate signal SG2; a transistor Tr1, to which the gate signal SG1 is input; a transistor Tr2, to which the gate signal SG2 is input; an inductor element L0, one end of which is electrically connected to the transistor Tr1 and the transistor Tr2, and the other end of which is electrically connected to the output terminal Tn-out for outputting the drive signal Com; a substrate 51, on which the integrated circuit 40, the transistor Tr1, the transistor Tr2 and the inductor element L0 are mounted; and a heat sink 56, which is mounted on the opposite side of the substrate 51 as viewed from the transistor Tr1, and dissipates heat from a surface 602 opposite to the substrate 51 among the multiple surfaces of the chip main body 60 of the transistor Tr1.

[0227] In Supplementary Note 3, the surface 602 is an example of the “first surface”, and the heat sink 56 is an example of the “first heat sink”.

[0228] According to Supplementary Note 3-1, the drive signal generating unit 5C includes the heat sink 56. Therefore, heat can be dissipated from the transistor Tr1 not only from the substrate 51 side but also from the side opposite to the substrate 51. Therefore, according to Supplementary Note 3-1, compared with a configuration in which the drive signal generating unit 5C does not include the heat sink 56, heat dissipation in the transistor Tr1 can be improved, and the temperature of the transistor Tr1 can be suppressed.

[0229] Note 3-2

[0230] The inkjet printer 1 according to Supplementary Note 3-2 is the inkjet printer 1 according to Supplementary Note 3-1, further comprising a mold member 55 covering the transistor Tr1 on the substrate 51, and wherein the pH of the liquid ejected from the liquid ejection unit 3 is 3 or less.

[0231] According to Supplementary Note 3-2, the drive signal generating unit 5C includes the mold member 55 covering the transistor Tr1. Therefore, even when liquid with a pH of 3 or less is ejected from the liquid ejecting unit 3 and metal corrosion is likely to occur in the inkjet printer 1, the possibility of corrosion of the transistor Tr1 can be reduced.

[0232] Note 3-3

[0233] The inkjet printer 1 involved in Note 3-3 is the inkjet printer 1 involved in Note 3-1 or Note 3-2, and is characterized in that it comprises: a slide 110, which carries a liquid ejection unit 3 and a drive signal generating unit 5C, and moves on the recording paper PP on which ink is ejected by the liquid ejection unit 3; and a slide conveying motor 91, which is used to move the slide 110, and the liquid ejection unit 3 ejects ink when the slide 110 moves.

[0234] According to Supplementary Note 3-3, the drive signal generating unit 5C is mounted on the carriage 110 and moves. Therefore, compared with a configuration in which the drive signal generating unit 5C is not mounted on the carriage 110 , heat can be efficiently dissipated from the heat sink 56 .

[0235] Notes 3-4

[0236] The inkjet printer 1 according to Supplementary Note 3-4 is the inkjet printer 1 according to Supplementary Note 3-1 to Supplementary Note 3-3, and is characterized in that the transistor Tr1 has a Cu clip structure.

[0237] According to Supplementary Note 3-4, compared with a configuration in which the transistor Tr1 does not have a Cu clip structure, heat dissipation in the transistor Tr1 can be improved, and the temperature of the transistor Tr1 can be suppressed from rising.

[0238] Notes 3-5

[0239] The inkjet printer 1 according to Supplement 3-5 is characterized in that it is the inkjet printer 1 according to Supplement 3-1 to Supplement 3-4. The transistor Tr1 includes a chip body 60; a source electrode 61s provided on a surface 602 among the multiple surfaces of the chip body 60; and a drain electrode 61d provided on a surface 601 opposite to the surface 602 among the multiple surfaces of the chip body 60. The drain electrode 61d is connected to a drain connection terminal 62d provided on the substrate 51. The source electrode 61s is connected to a conductive clip 63, and the clip 63 is connected to a source connection terminal 62s provided on the substrate 51.

[0240] In addition, in Supplementary Note 3, surface 601 is an example of the "second surface".

[0241] According to Notes 3-5, the heat generated in the source electrode 61s and the drain electrode 61d of the transistor Tr1, which generate a lot of heat, is dissipated from the two surfaces 601 and 602 of the chip main body 60. Therefore, compared with the method of dissipating heat from a single surface of the chip main body 60, the heat dissipation performance of the transistor Tr1 can be improved.

[0242] Notes 3-6

[0243] The inkjet printer 1 involved in Note 3-6 is the inkjet printer 1 involved in Notes 3-1 to 3-5, and is characterized in that the transistor Tr1 has: a chip main body 60; a drain electrode 61d, which is arranged on a surface 602 among the multiple surfaces of the chip main body 60; and a source electrode 61s, which is arranged on a surface 601 opposite to the surface 602 among the multiple surfaces of the chip main body 60, the source electrode 61s is connected to a source connection terminal 62s provided on the substrate 51, and the drain electrode 61d is connected to a conductive clip 63, and the clip 63 is connected to a drain connection terminal 62d provided on the substrate 51.

[0244] According to Note 3-6, the heat generated in the source electrode 61s and the drain electrode 61d of the transistor Tr1, which generate a lot of heat, is dissipated from the two surfaces 601 and 602 of the chip main body 60. Therefore, compared with the method of dissipating heat from a single surface of the chip main body 60, the heat dissipation performance of the transistor Tr1 can be improved.

[0245] Notes 3-7

[0246] The inkjet printer 1 according to Supplementary Note 3-7 is the inkjet printer 1 according to Supplementary Note 3-1 to Supplementary Note 3-6, and is characterized in that the heat sink 56 includes a main body portion 560 formed of copper or aluminum, and the main body portion 560 is coated with graphene.

[0247] According to Supplementary Note 3-7, since heat sink 56 is coated with graphene, the heat dissipation performance of heat sink 56 can be improved compared to a case where heat sink 56 is not coated with graphene. Furthermore, since heat sink 56 is coated with graphene according to Supplementary Note 3-7, the possibility of corrosion of main body portion 560 of heat sink 56 can be reduced compared to a case where heat sink 56 is not coated with graphene, thereby suppressing the reduction in heat dissipation performance of heat sink 56 that would otherwise occur due to corrosion of heat sink 56.

[0248] Notes 3-8

[0249] The inkjet printer 1 according to Supplementary Note 3-8 is the inkjet printer 1 according to Supplementary Note 3-1 to Supplementary Note 3-7, wherein the gate signal SG1 is a signal for designating on / off switching of the transistor Tr1 and has a frequency of 1 MHz to 8 MHz.

[0250] According to Supplementary Note 3-8, it is possible to achieve both improvement in the accuracy of the waveform of the drive signal Com generated in the drive signal generating unit 5C including the transistor Tr1 and reduction in the switching loss in the transistor Tr1.

[0251] Notes 3-9

[0252] The inkjet printer 1 according to Supplementary Note 3 - 9 is the inkjet printer 1 according to Supplementary Note 3 - 1 to Supplementary Note 3 - 8 , and is characterized in that it includes a mold member 55 that covers the transistor Tr1 and the transistor Tr2 on the substrate 51 .

[0253] According to Supplementary Note 3-9, the two transistors Tr1 and Tr2 are integrated into one package. Therefore, compared with a system in which the transistors Tr1 and Tr2 are separate, the component constant and the mounting area of ​​the transistors Tr1 and Tr2 can be reduced.

[0254] Note 3-10

[0255] The inkjet printer 1 according to Supplementary Note 3 - 10 is the inkjet printer 1 according to Supplementary Note 3 - 1 to Supplementary Note 3 - 9 , and is characterized in that it includes a heat sink 52 fixed to a base plate 51 .

[0256] In addition, in Supplementary Note 3, the radiator 52 is an example of a “second radiator”.

[0257] According to Supplementary Note 3-10, heat dissipation by the heat sink 56 and the heat sink 52 can be performed, so that the heat dissipation efficiency in the drive signal generating unit 5C can be improved compared with a configuration without the heat sink 52.

Claims

1. A liquid ejection device, characterized in that: have: a liquid ejection unit including a driving element driven by a driving signal and ejecting liquid in response to the driving of the driving element; and a driving signal generating unit, generating the driving signal, The driving signal generating unit comprises: An integrated circuit outputs a first control signal and a second control signal; a first transistor to which the first control signal is input; a second transistor to which the second control signal is input; a coil, one end of which is electrically connected to the first transistor and the second transistor, and the other end of which is electrically connected to an output terminal for outputting the driving signal; a substrate on which the integrated circuit, the first transistor, the second transistor, and the coil are mounted; as well as a molding member covering the first transistor on the substrate, The first transistor has a Cu clip structure.

2. The liquid ejection device according to claim 1, wherein The pH of the liquid ejected from the liquid ejecting unit is 3 or less.

3. The liquid ejection device according to claim 1, wherein have: a carriage carrying the liquid ejecting unit and the drive signal generating unit and moving on a medium from which the liquid is ejected by the liquid ejecting unit; and a motor for moving the carriage, The liquid ejecting unit ejects liquid when the carriage moves.

4. The liquid ejection device according to claim 1, wherein The first transistor comprises: Chip main body; a drain electrode provided on a first surface facing the substrate among a plurality of surfaces of the chip main body; as well as a source electrode provided on a second surface opposite to the first surface among the plurality of surfaces of the chip main body; The drain electrode is connected to a drain connection terminal provided on the substrate, The source electrode is connected to a conductive clip, The clip is connected to a source connection terminal provided on the substrate.

5. The liquid ejection device according to claim 1, wherein The first transistor comprises: Chip main body; a source electrode provided on a first surface facing the substrate among a plurality of surfaces of the chip main body; as well as a drain electrode provided on a second surface opposite to the first surface among the plurality of surfaces of the chip main body; The source electrode is connected to a source connection terminal provided on the substrate, The drain electrode is connected to a conductive clip, The clip is connected to a drain connection terminal provided on the substrate.

6. The liquid ejection device according to claim 1, wherein The first control signal is a signal that specifies whether the first transistor is turned on or off, and has a frequency of 1 MHz to 8 MHz.

7. The liquid ejection device according to claim 1, wherein The molding member covers the first transistor and the second transistor on the substrate.

8. A liquid ejection unit, characterized in that: A liquid ejection unit includes a driving element driven by a driving signal and ejects liquid according to the driving of the driving element, and includes: An integrated circuit outputs a first control signal and a second control signal; a first transistor to which the first control signal is input; a second transistor to which the second control signal is input; a coil, one end of which is electrically connected to the first transistor and the second transistor, and the other end of which is electrically connected to an output terminal for outputting the driving signal; a substrate on which the integrated circuit, the first transistor, the second transistor, and the coil are mounted; as well as a molding member covering the first transistor on the substrate, The first transistor has a Cu clip structure.

9. The liquid ejection unit according to claim 8, wherein: The pH of the liquid ejected from the liquid ejecting unit is 3 or less.

10. The liquid ejection unit according to claim 8, wherein The liquid ejecting unit is mounted on a carriage that moves on a medium from which the liquid is ejected by the liquid ejecting unit, and ejects the liquid when the carriage is moved by a motor for moving the carriage.

11. The liquid ejection unit according to claim 8, wherein The first transistor comprises: Chip main body; a drain electrode provided on a first surface facing the substrate among a plurality of surfaces of the chip main body; as well as a source electrode provided on a second surface opposite to the first surface among the plurality of surfaces of the chip main body; The drain electrode is connected to a drain connection terminal provided on the substrate, The source electrode is connected to a conductive clip, The clip is connected to a source connection terminal provided on the substrate.

12. The liquid ejection unit according to claim 8, wherein The first transistor comprises: Chip main body; a source electrode provided on a first surface facing the substrate among a plurality of surfaces of the chip main body; as well as a drain electrode provided on a second surface opposite to the first surface among the plurality of surfaces of the chip main body; The source electrode is connected to a source connection terminal provided on the substrate, The drain electrode is connected to a conductive clip, The clip is connected to a drain connection terminal provided on the substrate.

13. The liquid ejection unit according to claim 8, wherein The first control signal is a signal that specifies whether the first transistor is turned on or off, and has a frequency of 1 MHz to 8 MHz.

14. The liquid ejection unit according to claim 8, wherein The molding member covers the first transistor and the second transistor on the substrate.

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