Liquid dispensing device and head unit

Abstract

This suppresses noise generation caused by apertures in the circuit board. [Solution] A liquid dispensing device comprising: a dispensing unit that is driven by a drive signal to dispense liquid; a circuit board on which a drive circuit that generates a drive signal is arranged; a housing that houses the circuit board; and screw parts that connect the circuit board and the housing, wherein the circuit board has a substrate region in which no openings are formed, and the screw parts are fixed to the circuit board in the substrate region.

Description

Technical Field

[0001] The present invention relates to a liquid ejection device and a head unit.

Background Art

[0002] There is known a liquid ejection device including a drive circuit that generates a drive signal and a discharge unit that is driven by the drive signal to discharge a liquid. In such a liquid ejection device, since the drive signal for driving the discharge unit is a large-amplitude signal, the drive circuit generates heat when generating the drive signal, and the drive circuit becomes high temperature. For this reason, conventionally, various configurations for cooling the drive circuit have been proposed. For example, in Patent Document 1, there is disclosed a configuration for suppressing the temperature rise of the drive circuit by radiating heat emitted from the drive circuit through a screw inserted into an opening provided in a circuit board on which the drive circuit is disposed and connecting the housing that houses the circuit board and the circuit board via the screw.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, according to the conventional technology, in order to fix the screw to the circuit board, an opening was provided in the circuit board, and thus the opening sometimes functioned as an antenna. For this reason, according to the conventional technology, signals from the opening of the circuit board functioning as an antenna sometimes overlapped as noise with various signals generated by the drive circuit such as the drive signal.

Means for Solving the Problems

[0005] To solve the above problems, the liquid dispensing device according to the present invention comprises a dispensing unit that is driven by a drive signal to dispense liquid, a circuit board on which a drive circuit that generates the drive signal is arranged, a housing that houses the circuit board, and screw parts that connect the circuit board and the housing, wherein the circuit board has a substrate region in which no openings are formed, and the screw parts are fixed to the circuit board in the substrate region.

[0006] Furthermore, the head unit according to the present invention comprises a discharge unit that is driven by a drive signal to discharge liquid, a circuit board on which a drive circuit that generates the drive signal is arranged, and a screw component that connects the circuit board and a housing that houses the circuit board, wherein the circuit board has a substrate region in which no openings are formed, and the screw component is fixed to the circuit board in the substrate region. [Brief explanation of the drawing]

[0007] [Figure 1] This block diagram shows an example of the configuration of an inkjet printer 1 according to an embodiment of the present invention. [Figure 2] This is a perspective view showing an example of the general internal structure of inkjet printer 1. [Figure 3] This is a cross-sectional view showing an example of the structure of the discharge section D[m]. [Figure 4] This block diagram shows an example of the configuration of head unit 3. [Figure 5] This is a timing chart showing an example of the signals supplied to head unit 3. [Figure 6] This is an explanatory diagram showing an example of an individual designation signal Sd[m]. [Figure 7] This is a block diagram showing an example of the configuration of the drive signal generation circuit 40. [Figure 8] This is an exploded perspective view showing an example of the structure of the drive signal generation unit 4 and the screw component 5. [Figure 9] This is a cross-sectional view showing an example of the structure of the drive signal generation unit 4 and the screw component 5. [Figure 10] It is a plan view showing an example of the structure of the drive signal generation unit 4 and the screw component 5. [Figure 11] It is a cross-sectional view showing an example of the structure of the inkjet printer according to Comparative Ratio 1. [Figure 12] It is a cross-sectional view showing an example of the structure of the inkjet printer according to Comparative Ratio 2. [Figure 13] It is a cross-sectional view showing an example of the structure of the inkjet printer according to Modification Example 2 of the present invention. [Figure 14] It is a plan view showing an example of the structure of the inkjet printer according to Modification Example 2 of the present invention. [Figure 15] It is a block diagram showing an example of the configuration of the inkjet printer 1C according to Modification Example 5 of the present invention.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, in each figure, the dimensions and scales of each part are appropriately different from the actual ones. Further, the embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are imposed. However, the scope of the present invention is not limited to these embodiments unless there is a description to particularly limit the present invention in the following description.

[0009] <<A. Embodiment>> Hereinafter, a liquid ejection device will be described by exemplifying an inkjet printer 1 that ejects ink to form an image on a recording paper PP.

[0010] <<A.1. Outline of Inkjet Printer 1>> Hereinafter, an example of the configuration of the inkjet printer 1 according to the present embodiment will be described while referring to FIGS. 1 to 3.

[0011] FIG. 1 is a functional block diagram showing an example of the configuration of the inkjet printer 1.

[0012] As shown in FIG. 1, print data Img indicating an image to be formed by the inkjet printer 1 is supplied to the inkjet printer 1 from a host computer such as a personal computer or a digital camera. The inkjet printer 1 executes a printing process for forming an image indicated by the print data Img supplied from the host computer on a recording paper PP.

[0013] As shown in FIG. 1, the inkjet printer 1 includes a control unit 2 that controls each part of the inkjet printer 1, a head unit 3 provided with a discharge unit D that discharges ink onto the recording paper PP, a drive signal generation unit 4 provided with a drive signal generation circuit 40 that generates a drive signal Com for driving the discharge unit D, and a conveyance unit 9 for conveying the head unit 3 and the recording paper PP. In the present embodiment, the inkjet printer 1 is an example of a "liquid discharge device", the ink is an example of a "liquid", and the drive signal generation circuit 40 is an example of a "drive circuit".

[0014] In the present embodiment, it is assumed that the inkjet printer 1 includes one or more head units 3. Specifically, in the present embodiment, as an example, it is assumed that the inkjet printer 1 includes four head units 3. In the following, for convenience of explanation, there may be cases where, as shown in FIG. 1, an explanation is given by focusing on one of the four head units 3.

[0015] Furthermore, in this embodiment, as an example, we assume that the drive signal generation unit 4 is equipped with one or more drive signal generation circuits 40 corresponding to one head unit 3. Specifically, in this embodiment, we assume that the drive signal generation unit 4 is equipped with one drive signal generation circuit 40 corresponding to one head unit 3. That is, in this embodiment, we assume that the drive signal generation unit 4 is equipped with four drive signal generation circuits 40 corresponding to four head units 3. However, the present invention is not limited to these embodiments. The drive signal generation unit 4 may be equipped with two drive signal generation circuits 40 corresponding to one head unit 3, or it may be equipped with three or more drive signal generation circuits 40 corresponding to one head unit 3. For the sake of explanation, in the following, as shown in Figure 1, we may focus on one of the four drive signal generation circuits 40 in the explanation.

[0016] The control unit 2 is comprised of a control circuit (not shown) and a memory circuit (not shown). The memory circuit is composed of volatile memory such as RAM (Random Access Memory) and non-volatile memory such as ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), or PROM (Programmable ROM), and stores various information such as the control program for the inkjet printer 1. The control circuit consists of one or more CPUs (Central Processing Units). However, the control circuit may include a programmable logic device such as an FPGA (field-programmable gate array) instead of a CPU, or in addition to a CPU. The control circuit executes the control program for the inkjet printer 1 stored in the memory circuit and controls each part of the inkjet printer 1 by operating according to the control program. Specifically, the control circuit generates signals for controlling the operation of each part of the inkjet printer 1, such as a designation signal SI, a waveform designation signal dCom, and a carrier control signal SH.

[0017] Here, the waveform specification signal dCom is a digital signal that defines the waveform of the drive signal Com. The drive signal Com is an analog signal for driving the ejection unit D. The specification signal SI is a digital signal that specifies the type of operation of the ejection unit D. Specifically, the specification signal SI specifies whether or not to supply the drive signal Com to the ejection unit D, thereby specifying the type of operation of the ejection unit D, such as whether or not ink is ejected from the ejection unit D. The transport control signal SH is a signal for controlling the transport unit 9.

[0018] When printing is performed, the control unit 2 generates signals to control the head unit 3, such as a specified signal SI, based on the print data Img. The control unit 2 also generates signals to control the drive signal generation unit 4, such as a waveform specified signal dCom, when printing is performed. Furthermore, the control unit 2 generates signals to control the transport unit 9, such as a transport control signal SH, when printing is performed. In this way, during printing, the control unit 2 controls the transport unit 9 to move the head unit 3 and the recording paper PP, while adjusting the presence or absence of ink ejection from the ejection unit D, the ink ejection timing, etc., thereby controlling each part of the inkjet printer 1 so that an image corresponding to the print data Img is formed on the recording paper PP.

[0019] As shown in Figure 1, the head unit 3 comprises a supply circuit 31 and a head section 32.

[0020] The print head 32 is equipped with M ejection units D. Here, the value M is a natural number satisfying "M≧1". In the following, the m-th ejection unit D among the M ejection units D provided in the print head 32 may be referred to as ejection unit D[m]. Here, the variable m is a natural number satisfying "1≦m≦M". Furthermore, in the following, if a component or signal of the inkjet printer 1 corresponds to ejection unit D[m] among the M ejection units D, the subscript [m] may be added to the code used to represent that component or signal. The supply circuit 31 switches whether or not to supply the drive signal Com to the discharge unit D[m] based on the specified signal SI. Hereinafter, the drive signal Com supplied to the discharge unit D[m] may be referred to as the supply drive signal Vin[m].

[0021] Figure 2 is a perspective view showing an example of the schematic internal structure of inkjet printer 1.

[0022] As shown in Figure 2, in this embodiment, we assume that the inkjet printer 1 is a serial printer. Specifically, when the inkjet printer 1 performs a printing process, it transports the recording paper PP in the X1 direction, and while moving the head unit 3 in the Y1 direction which intersects the X1 direction, or in the Y2 direction which is opposite to the Y1 direction, it ejects ink from the head unit 3 to form an image on the recording paper PP according to the print data Img.

[0023] In the following, the X1 direction and its opposite direction, the X2 direction, will be collectively referred to as the "X-axis direction," the Y1 direction intersecting the X-axis direction and its opposite direction, the Y2 direction, will be collectively referred to as the "Y-axis direction," and the Z1 direction intersecting the X-axis and Y-axis directions and its opposite direction, the Z2 direction, will be collectively referred to as the "Z-axis direction." In this embodiment, as an example, the case in which the X-axis direction, Y-axis direction, and Z-axis direction are mutually orthogonal will be described. However, the present invention is not limited to this embodiment. The X-axis direction, Y-axis direction, and Z-axis direction only need to intersect each other. In this embodiment, the Z1 direction is the direction in which ink is ejected from the ejection unit D.

[0024] As shown in Figure 2, the inkjet printer 1 according to this embodiment comprises a housing 100 and a carriage 110 that can reciprocate within the housing 100 in the Y-axis direction.

[0025] As shown in Figure 2, this embodiment assumes that the carriage 110 is equipped with four ink cartridges 120, each corresponding one-to-one with four inks: cyan, magenta, yellow, and black. Furthermore, this embodiment assumes that the carriage 110 is equipped with four head units 3, each corresponding one-to-one with the four ink cartridges 120. Each ejection unit D[m] receives ink from the ink cartridge 120 corresponding to the head unit 3 on which the ejection unit D[m] is provided. As a result, each ejection unit D[m] fills itself with the supplied ink, and the ink filled inside the ejection unit D[m] can be ejected from the nozzle N provided in the ejection unit D[m]. Note that the ink cartridges 120 may be provided outside the carriage 110.

[0026] As described above, the inkjet printer 1 according to this embodiment includes a transport unit 9. As shown in Figure 2, the transport unit 9 includes a carriage transport motor 91, a media transport motor 92, a media transport mechanism 93, a platen 95, a carriage guide shaft 96, and a belt 97. The carriage transport motor 91 drives the belt 97 based on a transport control signal SH. The belt 97 transports the carriage 110 in the Y-axis direction based on the drive of the carriage transport motor 91. The carriage guide shaft 96 supports the carriage 110 so that it can reciprocate in the Y-axis direction. The media transport motor 92 drives the media transport mechanism 93 based on a transport control signal SH. The media transport mechanism 93 transports the recording paper PP in the X1 direction by rotating based on the drive of the media transport motor 92. The platen 95 is provided in the Z1 direction of the carriage 110 and supports the recording paper PP being transported by the media transport mechanism 93. In this way, when printing is performed, the transport unit 9 uses the carriage transport motor 91 to reciprocate the head unit 3 and the carriage 110 together along the carriage guide axis 96 in the Y-axis direction, and the media transport motor 92 transports the recording paper PP on the platen 95 in the X1 direction, thereby changing the relative position of the recording paper PP with respect to the head unit 3 and enabling ink to land on the entire surface of the recording paper PP.

[0027] Figure 3 is a schematic partial cross-sectional view of the head portion 32, which is cut to include the discharge portion D [m].

[0028] As shown in FIG. 3, the ejection unit D[m] includes a piezoelectric element PZ[m], a cavity CV[m] filled with ink inside, a nozzle N[m] communicating with the cavity CV[m], and a diaphragm 321. When the piezoelectric element PZ[m] is driven by a supply drive signal Vin[m], the ejection unit D[m] ejects the ink in the cavity CV[m] from the nozzle N[m]. The cavity CV[m] is a space partitioned by a cavity plate 324, a nozzle plate 323 in which the nozzle N[m] is formed, and the diaphragm 321. The cavity CV[m] communicates with a reservoir 325 via an ink supply port 326. The reservoir 325 communicates with an ink cartridge 120 corresponding to the ejection unit D[m] via an ink inlet 327. The piezoelectric element PZ[m] has an upper electrode Zu[m], a lower electrode Zd[m], and a piezoelectric body Zm[m] provided between the upper electrode Zu[m] and the lower electrode Zd[m]. The lower electrode Zd[m] is electrically connected to a power supply line LD set to a predetermined potential VBS. When a supply drive signal Vin[m] is supplied to the upper electrode Zu[m] and a voltage is applied between the upper electrode Zu[m] and the lower electrode Zd[m], the piezoelectric element PZ[m] is displaced in the Z1 direction and the Z2 direction according to the applied voltage, and as a result, the piezoelectric element PZ[m] vibrates. The lower electrode Zd[m] is joined to the diaphragm 321. Therefore, when the piezoelectric element PZ[m] is driven by the supply drive signal Vin[m] and vibrates, the diaphragm 321 also vibrates. Then, due to the vibration of the diaphragm 321, the volume of the cavity CV[m] and the pressure inside the cavity CV[m] change, and the ink filled in the cavity CV[m] is ejected from the nozzle N[m].

[0029] <<A.2. Configuration and Operation of Head Unit 3>> Hereinafter, an example of the configuration and operation of the head unit 3 will be described while referring to FIGS. 4 to 6.

[0030] FIG. 4 is a block diagram showing an example of the configuration of the head unit 3.

[0031] As shown in Figure 4, the head unit 3 comprises a supply circuit 31 and a head unit 32. The head unit 3 also includes wiring LC to which the drive signal Com is supplied from the drive signal generation unit 4.

[0032] As shown in Figure 4, the supply circuit 31 comprises M switches WS[1] to WS[M] that correspond one-to-one with M discharge units D[1] to D[M], and a connection state specification circuit 310 that specifies the connection state of each switch. The connection status specification circuit 310 generates a connection status specification signal QS[m] that specifies whether the switch WS[m] is on or off, based on at least some of the signals supplied from the control unit 2: the specification signal SI, the latch signal LAT, the change signal CH, and the clock signal CLK. The switch WS[m] switches between conductivity and non-conductivity between the wiring LC and the upper electrode Zu[m] of the piezoelectric element PZ[m] provided in the discharge section D[m], based on the connection status specification signal QS[m]. In this embodiment, the switch WS[m] is turned on when the connection status specification signal QS[m] is high level and turned off when it is 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 discharge section D[m] as the supply drive signal Vin[m].

[0033] Figure 5 is a timing chart showing an example of various signals, such as the drive signal Com, supplied to the head unit 3.

[0034] As shown in Figure 5, when the inkjet printer 1 performs a printing process, one or more unit periods TP are set as the operating period of the inkjet printer 1. In this embodiment, the inkjet printer 1 can drive each ejection unit D[m] for the printing process during each unit period TP.

[0035] As shown in Figure 5, the control unit 2 outputs a latch signal LAT which has a pulse PLL. This allows the control unit 2 to define a unit period TP as the period from the rising edge of one pulse PLL to the rising edge of the next pulse PLL. The control unit 2 also outputs a change signal CH which has a pulse PLC during the unit period TP. The control unit 2 then divides the unit period TP into a drive period TQ1, from the rising edge of the pulse PLL to the rising edge of the pulse PLC, and a drive period TQ2, from the rising edge of the pulse PLC to the rising edge of the pulse PLL.

[0036] As shown in Figure 5, the designation signal SI includes M individual designation signals Sd[1] to Sd[M] that correspond one-to-one with M ejection units D[1] to D[M]. The individual designation signals Sd[m] specify the mode of operation of the ejection units D[m] in each unit period TP when the inkjet printer 1 performs printing. Prior to each unit period TP, the control unit 2 supplies the designation signal SI, which includes the M individual designation signals Sd[1] to Sd[M], to the connection state designation circuit 310 in synchronization with the clock signal CLK. The connection state designation circuit 310 then generates a connection state designation signal QS[m] based on the individual designation signals Sd[m] in the unit period TP.

[0037] In this embodiment, it is assumed that during a unit period TP in which the printing process is performed, the ejection unit D[m] is capable of forming any of the following dots: a large dot made of ink with an ink amount ξ1, a medium dot made of ink with an ink amount ξ2 less than ξ1, and a small dot made of ink with an ink amount ξ3 less than ξ2.

[0038] Figure 6 is an explanatory diagram illustrating an example of an individual designation signal Sd[m].

[0039] As shown in Figure 6, in this embodiment, the individual designation signal Sd[m] can take any one of four values ​​during the unit period TP in which the printing process is performed: a value of "1" which designates the ejection unit D[m] as the large dot forming ejection unit DP-1, a value of "2" which designates the ejection unit D[m] as the medium dot forming ejection unit DP-2, a value of "3" which designates the ejection unit D[m] as the small dot forming ejection unit DP-3, and a value of "4" which designates the ejection unit D[m] as the non-dot forming ejection unit DP-4. Here, the large dot-forming discharge section DP-1 is the discharge section D that forms large dots in a unit period TP. The medium dot-forming discharge section DP-2 is the discharge section D that forms medium dots in a unit period TP. The small dot-forming discharge section DP-3 is the discharge section D that forms small dots in a unit period TP. The non-dot-forming discharge section DP-4 is the discharge section D that does not form dots in a unit period TP.

[0040] Return to the explanation in Figure 5. As shown in Figure 5, in this embodiment, the drive signal Com has a waveform PA1 provided during the drive period TQ1 and a waveform PA2 provided during the drive period TQ2. Of these, waveform PA1 is a waveform that returns to potential V0, passing through potential VL1 which is lower than potential V0, and potential VH1 which is higher than potential V0. When a supply drive signal Vin[m] having waveform PA1 is supplied to the ejection unit D[m], waveform PA1 is defined so that ink equivalent to ink amount φ1 is ejected from the ejection unit D[m]. Waveform PA2 is a waveform that returns to potential V0, passing through potential VL2 which is lower than potential V0, and potential VH2 which is higher than potential V0. When a supply drive signal Vin[m] having waveform PA2 is supplied to the ejection unit D[m], waveform PA2 is defined so that ink equivalent to ink amount φ2 is ejected from the ejection unit D[m]. In this embodiment, it is assumed that ink quantity ξ1 corresponds to the sum of ink quantity φ1 and ink quantity φ2, ink quantity ξ2 corresponds to ink quantity φ1, and ink quantity ξ3 corresponds to ink quantity φ2.

[0041] Furthermore, in this embodiment, as an example, we assume that when the potential of the supply drive signal Vin[m] supplied to the ejection unit D[m] is high, the volume of the cavity CV[m] in the ejection unit D[m] becomes smaller compared to when the potential is low. Therefore, when the ejection unit D[m] is driven by a supply drive signal Vin[m] having a waveform PA1 or the like, the ink in the ejection unit D[m] is ejected from the nozzle N[m] as the potential of the supply drive signal Vin[m] changes from low to high.

[0042] As shown in Figure 6, when the individual designation signal Sd[m] indicates a value of "1" which designates the ejection unit D[m] as the large dot forming ejection unit DP-1 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 drive period TQ1 and the drive period TQ2. In this case, the switch WS[m] is turned on during the drive period TQ1 and the drive period TQ2. Therefore, during the unit period TP, the ejection unit D[m] is driven by the supply drive signal Vin[m] which has waveforms PA1 and PA2, and ejects ink with an ink amount ξ1 corresponding to a large dot. Furthermore, if the individual designation signal Sd[m] indicates a value of "2" which designates the ejection unit D[m] as the medium dot forming ejection 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 drive period TQ1. In this case, the switch WS[m] is turned on during the drive period TQ1. Therefore, during the unit period TP, the ejection unit D[m] is driven by the supply drive signal Vin[m] having waveform PA1 and ejects ink with an ink amount ξ2 corresponding to the medium dot. Furthermore, if the individual designation signal Sd[m] indicates a value of "3" which designates 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 drive period TQ2. In this case, the switch WS[m] is turned on during the drive period TQ2. Therefore, during the unit period TP, the ejection unit D[m] is driven by the supply drive signal Vin[m] having waveform PA2 and ejects ink with an ink amount ξ3 corresponding to a small dot. Also, when the individual designation signal Sd[m] indicates the value "4" that designates the discharge unit D[m] as a dot non-forming discharge unit DP-4 in the unit period TP, the connection state designation circuit 310 sets the connection state designation signal QS[m] to the low level throughout the unit period TP. In this case, the switch WS[m] turns off throughout the unit period TP. Therefore, the discharge unit D[m] is not driven by the supply drive signal Vin[m] and does not discharge ink in the unit period TP.

[0043] <<Configuration of Drive Signal Generation Circuit 40 of Drive Signal Generation Unit 4>> Hereinafter, an example of the configuration of the drive signal generation circuit 40 provided in the drive signal generation unit 4 will be described with reference to FIG. 7.

[0044] FIG. 7 is a block diagram showing an example of the circuit configuration of the drive signal generation circuit 40.

[0045] As shown in FIG. 7, the drive signal generation circuit 40 includes an integrated circuit 41, an amplifier circuit 43, a smoothing circuit 44, a pull-up circuit 45, and a filter circuit 46, and generates a drive signal Com based on the waveform designation signal dCom.

[0046] The integrated circuit 41 is, for example, an LSI (Large Scale Integration), and generates a gate signal SGH and a gate signal SGL based on the waveform designation signal dCom. The integrated circuit 41 includes an analog conversion circuit 412, a subtractor 414, an adder 416, an attenuator 418, an integral attenuator 422, a comparator 424, and a gate driver 426.

[0047] The analog conversion circuit 412 is a DAC (digital to analog converter) that converts the digital waveform designation signal dCom into an analog signal Aa. The voltage amplitude of the signal Aa is, for example, about 0 to 2 volts, and the drive signal Com is obtained by amplifying this voltage by about 20 times. That is, the signal Aa is the signal before amplification of the drive signal Com. The integrating attenuator 422 outputs a signal Ax obtained by attenuating the signal SN1 input to terminal Tn1 (described later) and then integrating it. The subtractor 414 outputs a signal Ab, which represents the potential obtained by subtracting the potential of signal Aa from the potential of signal Ax. The attenuator 418 outputs a signal Ay, which is the signal SN2 input to terminal Tn2 (described later) with its high-frequency components attenuated. The adder 416 outputs a signal As, which represents the potential obtained by adding the potentials of signal Ab and signal Ay. Comparator 424 outputs a modulated signal Ms obtained by pulse-modulating signal As. Specifically, comparator 424 outputs a modulated signal Ms that is high level when signal As's voltage rises above threshold voltage Vth1, and low level when signal As's voltage falls below threshold voltage Vth2. The threshold voltages Vth1 and Vth2 are set to the relationship 'Vth1 > Vth2'.

[0048] The power supply voltage for the circuit from the analog conversion circuit 412 to the comparator 424 is a low voltage, such as 3.3 volts. In contrast, the drive signal Com has a large amplitude, sometimes exceeding 40 volts. Therefore, the integrating attenuator 422 attenuates the signal SN1, which has an amplitude corresponding to the drive signal Com, to match the amplitude range of the signal Ax to the amplitude range of the signal in the circuit from the analog conversion circuit 412 to the comparator 424. Furthermore, although a digital signal is used as an example to describe the waveform specification signal dCom in this embodiment, the waveform specification signal dCom can be any signal that defines the target value for generating the drive signal Com. For example, an analog signal Aa may be used as the waveform specification signal dCom. If signal Aa is the waveform specification signal dCom, the integrated circuit 41 may be configured without including the analog conversion circuit 412.

[0049] The gate driver 426 outputs a gate signal SGH, which is obtained by converting the modulated signal Ms to a specific amplitude, to terminal TnH. The gate driver 426 also outputs a gate signal SGL, which is obtained by converting the signal obtained by inverting the logic level of the modulated signal Ms to a specific amplitude, to terminal TnL.

[0050] The amplification circuit 43 includes, for example, transistors TrH and TrL, and generates an amplified signal Az, which is a signal obtained by amplifying the modulated signal Ms, based on the gate signals SGH and SGL output from the integrated circuit 41. In this embodiment, as an example, it is assumed that transistors TrH and TrL are N-channel field-effect transistors.

[0051] The gate signal SGH, output from gate driver 426, is input to the gate electrode of transistor TrH via terminal TnH and resistor RGH. Similarly, the gate signal SGL, output from gate driver 426, is input to the gate electrode of transistor TrL via terminal TnL and resistor RGL. The logic levels of gate signals SGH and SGL are mutually exclusive. Here, "mutually exclusive" means that the signal level of gate signal SGH supplied to the gate electrode of transistor TrH and the signal level of gate signal SGL supplied to the gate electrode of transistor TrL can never be high at the same time; in other words, transistors TrH and TrL can never be turned on at the same time. Transistor TrH turns on when the potential of its gate electrode is high and turns off when the potential of its gate electrode is low. Transistor TrH turns on when the potential of its gate electrode is high and turns off when the potential of its gate electrode is low.

[0052] The drain electrode of transistor TrH is electrically connected to the feed line set to the high-potential power supply potential VH, and its source electrode is electrically connected to node Nd. The source electrode of transistor TrL is grounded, and its drain electrode is electrically connected to node Nd. Alternatively, the source electrode of transistor TrL may be electrically connected to the feed line LD set to potential VBS.

[0053] As described above, transistor TrH turns on when the gate signal SGH supplied to its gate electrode is high level and turns off when it is low level. Similarly, transistor TrL turns on when the gate signal SGL supplied to its gate electrode is high level and turns off when it is low level. Therefore, the node Nd, which electrically connects the source electrode of transistor TrH and the drain electrode of transistor TrL, outputs an amplified signal Az, which is the amplified modulated signal Ms.

[0054] The smoothing circuit 44 is an LPF (Low Pass Filter) that smooths the amplified signal Az to generate the drive signal Com. The smoothing circuit 44 comprises 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 the output terminal Tn-out. One end of the capacitor C0 is electrically connected to the output terminal Tn-out, and the other end is grounded.

[0055] The pull-up circuit 45 feeds back the signal SN1, which is the drive signal Com output to the output terminal Tn-out, to terminal Tn1. The pull-up circuit 45 includes a resistor R1, one end of which is electrically connected to the output terminal Tn-out and the other end of which is electrically connected to terminal Tn1, and a resistor R2, one end of which is electrically connected to terminal Tn1 and the other end of which is electrically connected to a power supply line set to the power supply potential VH.

[0056] The filter circuit 46 is a Band Pass Filter (BPF) and feeds back a signal SN2, which is obtained by cutting the DC component from the frequency components of a predetermined band of the drive signal Com, to terminal Tn2. The filter circuit 46 comprises a resistor R3, a capacitor C1 with one end electrically connected to the output terminal Tn-out and the other end electrically connected to one end of resistor R3, a resistor R4 with one end electrically connected to one end of resistor R3 and the other end grounded, a capacitor C2 with one end electrically connected to the other end of resistor R3 and the other end grounded, and a capacitor C3 with one end electrically connected to the other end of resistor R3 and the other end electrically connected to terminal Tn2. Of these, capacitor C1 and resistor R4 function as a High Pass Filter (HPF) that allows high-frequency components of the drive signal Com above the cutoff frequency to pass through. Resistor R3 and capacitor C2 function as a Low Pass Filter (LPF) that allows low-frequency components of the drive signal Com below the cutoff frequency to pass through. In this embodiment, the cutoff frequency of the HPF in the filter circuit 46 is set lower than the cutoff frequency of the LPF. Therefore, the filter circuit 46 allows frequency components of the drive signal Com that are above the HPF cutoff frequency and below the LPF cutoff frequency to pass through. Furthermore, since the filter circuit 46 is equipped with a capacitor C3, the DC component is cut off from the signal of the drive signal Com that has passed through the HPF and LPF, and the resulting signal is fed back to terminal Tn2.

[0057] In this way, the drive signal generation circuit 40 generates the drive signal Com by smoothing the amplified signal Az at the node Nd with the smoothing circuit 44. The drive signal Com is integrated and subtracted by the integrator attenuator 422 and then fed back to the subtracter 414. Therefore, self-oscillation occurs at a frequency determined by the delay in the smoothing circuit 44, the delay in the integrator attenuator 422, and the feedback transfer function. However, since the delay amount of the feedback path via the terminal Tn1 is large, it is not possible to increase the self-oscillation frequency to such an extent that the accuracy of the waveform of the drive signal Com can be sufficiently ensured only by the feedback via the terminal Tn1. In contrast, in the present embodiment, a path for feeding back the high-frequency component of the drive signal Com via the terminal Tn2 is provided separately from the path via the terminal Tn1, so that the delay of the feedback in the entire drive signal generation circuit 40 can be reduced. That is, in the present embodiment, the frequency of the signal As obtained by adding the signal Ay, which is the high-frequency component of the drive signal Com, to the signal Ab can be increased as compared with the case where there is no path via the terminal Tn2, so that the accuracy of the drive signal Com can be sufficiently ensured.

[0058] <<Configuration of Drive Signal Generation Unit 4>> Hereinafter, the drive signal generation unit 4, the screw component 5, and the housing 800 will be described with reference to FIGS. 8 to 10.

[0059] FIG. 8 is an exploded perspective view showing an example of the configuration including the drive signal generation unit 4, the screw component 5, and the housing 800.

[0060] As shown in FIG. 8, the inkjet printer 1 includes a drive signal generation unit 4, a screw component 5, and a housing 800.

[0061] The housing 800 houses the drive signal generation unit 4. In the present embodiment, it is assumed that the housing 100 and the housing 800 are separate bodies and the housing 800 is housed inside the housing 100. However, the present invention is not limited to such an aspect. The housing 800 may be a part of the housing 100.

[0062] The drive signal generation unit 4 comprises a drive signal generation circuit 40 and a drive circuit board 400. The drive circuit board 400 is an example of a "circuit board" on which the drive signal generation circuit 40 is arranged.

[0063] The screw component 5 comprises a screw 51 and a nut 52, and fixes the drive signal generation unit 4 to the housing 800. Of these, the screw 51 is inserted through an opening 800K provided in the housing 800 and fixed to the housing 800. The nut 52 is fixed to the drive circuit board 400 in an area 400N of the drive circuit board 400 where no opening is formed, for example, by adhesive. Then, the screw 51 is inserted into the screw hole 500K provided in the nut 52, and the drive signal generation unit 4 is fixed to the housing 800 by fastening the screw 51 and the nut 52 together. Here, the area 400N where no opening is formed (an example of a "board area") is an area in the drive circuit board 400 where no opening is provided that penetrates the drive circuit board 400. In other words, in this embodiment, the screw component 5 is fixed to the drive circuit board 400 without providing an opening in the drive circuit board 400.

[0064] In Figure 8, an example is shown where the normal direction of the drive circuit board 400 is in the Z1 direction and the extending direction of the screw component 5 is in the Z1 direction; however, the present invention is not limited to this embodiment. The normal direction of the drive circuit board 400 and the extending direction of the screw component 5 may be any direction.

[0065] Figure 9 is a cross-sectional view showing an example of a configuration including the drive signal generation unit 4, screw component 5, and housing 800.

[0066] As shown in Figure 9, in this embodiment, the nut 52 includes a bottom plate portion 500. The bottom plate portion 500 is the part that constitutes the bottom surface of the screw hole 500K provided in the nut 52, and is the part located between the bottom surface of the screw hole 500K and the drive circuit board 400 when the nut 52 is fixed to the drive circuit board 400. In other words, in this embodiment, the screw hole 500K is a recess provided so as not to penetrate the nut 52.

[0067] More specifically, the base plate portion 500 has an upper surface 5001 and a lower surface 5002. The upper surface 5001 (an example of the "first surface") is the part corresponding to the bottom surface of the screw hole 500K. The lower surface 5002 (an example of the "second surface") is the surface of the base plate portion 500 opposite to the upper surface 5001, and is the part that comes into contact with the drive circuit board 400 when the nut 52 is fixed to the drive circuit board 400.

[0068] As shown in Figure 9, the drive circuit board 400 has an upper substrate surface 4001 and a lower substrate surface 4002. The upper substrate surface 4001 (an example of the "first substrate surface") is the surface to which the nut 52 is fixed. In this embodiment, it is assumed that the lower surface 5002 of the nut 52 and the upper substrate surface 4001 of the drive circuit board 400 are fixed together with adhesive BD. The lower substrate surface 4002 (an example of the "second substrate surface") is the surface of the drive circuit board 400 opposite to the upper substrate surface 4001, and is the surface on which the drive signal generation circuit 40, including the integrated circuit 41, the amplification circuit 43, and the smoothing circuit 44, is provided.

[0069] Furthermore, in this embodiment, it is assumed that the drive circuit board 400 is a multilayer substrate including a protective layer 401, a wiring layer 402, an insulating layer 403, and a surface layer 404 between the upper substrate surface 4001 and the lower substrate surface 4002.

[0070] The protective layer 401 is a layer that includes the upper substrate surface 4001 and is made of an insulating material. The wiring layer 402 is a layer on which wiring 402L is provided, and is located between the protective layer 401 and the lower substrate surface 4002. The wiring 402L is made of a conductive material. The portion of the wiring layer 402 other than the wiring 402L is made of an insulating material. The insulating layer 403 is the layer on which the wiring 403L is provided, and is located between the wiring layer 402 and the lower substrate surface 4002. The wiring 403L is made of a conductive material. The portion of the insulating layer 403 other than the wiring 403L is made of an insulating material. The surface layer 404 is a layer including the lower substrate surface 4002, on which a wiring 404L is provided. The wiring 404L is composed of a conductive material. The portion of the surface layer 404 other than the wiring 404L is a resist composed of an insulating material.

[0071] FIG. 10 is a plan view when the drive signal generation unit 4 is viewed in the Z2 direction.

[0072] As shown in FIG. 10, in the present embodiment, when the drive signal generation unit 4 is viewed in plan in the Z2 direction, the screw component 5 is provided at a position overlapping with the transistor TrH and the transistor TrL and at a position between the transistor TrH and the transistor TrL. Further, in the present embodiment, when the drive signal generation unit 4 is viewed in plan in the Z2 direction, the screw component 5 is arranged at a position overlapping with the wiring 402L. Furthermore, in the present embodiment, the drive signal generation circuit 40 and the screw component 5 are provided such that the screw component 5, the wiring 402L, and the transistor TrH overlap, and the screw component 5, the wiring 402L, and the transistor TrL overlap. Note that, in the present embodiment, the transistor TrH is an example of the "first electronic component", and the transistor TrL is an example of the "second electronic component".

[0073] <<A.5. Comparative example>> Hereinafter, in order to clarify the effects of the present embodiment, an inkjet printer according to a comparative example will be described while referring to FIGS. 11 and 12.

[0074] FIG. 11 is a cross-sectional view showing an example of the configuration of an inkjet printer according to Comparative Example 1.

[0075] As shown in FIG. 11, the inkjet printer according to Comparative Example 1 is configured in the same manner as the inkjet printer 1 according to the embodiment, except that it includes a drive signal generation unit 4Z instead of the drive signal generation unit 4 and a screw component 5Z instead of the screw component 5.

[0076] The drive signal generation unit 4Z differs from the drive signal generation unit 4 according to the embodiment in that it includes a drive circuit board 400Z instead of the drive circuit board 400. The drive circuit board 400Z includes a protective layer 401Z, a wiring layer 402Z, a wiring layer 403Z, and a surface layer 404Z. The protective layer 401Z differs from the protective layer 401 according to the embodiment in that it is provided with an opening 400K. The wiring layer 402Z differs from the wiring layer 402 according to the embodiment in that it is provided with an opening 400K. The wiring layer 403Z differs from the insulating layer 403 according to the embodiment in that it is provided with an opening 400K. The surface layer 404Z differs from the surface layer 404 according to the embodiment in that it is provided with an opening 400K. In other words, the drive circuit board 400Z differs from the drive circuit board 400 according to the embodiment in that it is provided with an opening 400K that penetrates the drive circuit board 400Z in the Z-axis direction.

[0077] The screw component 5Z comprises a screw 51Z and a nut 52Z. The nut 52Z differs from the nut 52 in the embodiment in that it does not have a bottom plate portion 500, and the screw hole 500K is provided so as to penetrate the nut 52Z in the Z-axis direction. The screw 51Z is inserted through the opening 400K in addition to the screw hole 500K, and is fixed to the nut 52 and the drive circuit board 400Z.

[0078] Thus, according to proportionality 1, an aperture 400K is provided on the drive circuit board 400Z. Therefore, according to proportionality 1, aperture 400K functions as an antenna, and the signal from this antenna may be superimposed on the drive signal Com as noise.

[0079] In contrast, according to the present embodiment, since the screw component 5 is fixed to the upper substrate surface 4001 of the drive circuit board 400 without providing an opening in the drive circuit board 400, the possibility that the drive circuit board 400 functions as an antenna can be reduced compared to Comparative Example 1. Therefore, according to the present embodiment, the possibility that noise is superimposed on the drive signal Com can be reduced compared to Comparative Example 1, and high-quality images can be formed by printing processing using the drive signal Com having a desired waveform.

[0080] FIG. 12 is a cross-sectional view showing an example of the configuration of an inkjet printer according to Comparative Example 2.

[0081] As shown in FIG. 12, the inkjet printer according to Comparative Example 2 is configured in the same manner as the inkjet printer 1 according to the embodiment, except that it includes a screw component 5W instead of the screw component 5.

[0082] The screw component 5W includes a screw 51 and a nut 52W. The nut 52W is different from the nut 52 according to the embodiment in that it does not have a bottom plate portion 500 and the screw hole 500K is provided so as to penetrate the nut 52W in the Z-axis direction. The nut 52W is inserted into the screw hole 500K and fixed to the nut 52W.

[0083] Thus, according to Comparative Example 2, the nut 52W does not include the bottom plate portion 500, and the screw hole 500K penetrates the nut 52W in the Z-axis direction. Therefore, according to Comparative Example 2, the intrusion of the adhesive BD into the screw hole 500K is allowed, and there is a possibility that the fastening of the screw 51 to the nut 52W becomes poor.

[0084] In contrast, according to the present embodiment, since the nut 52 includes the bottom plate portion 500, the intrusion of the adhesive BD into the screw hole 500K can be suppressed. Therefore, according to the present embodiment, the possibility that the fastening between the nut 52 and the screw 51 becomes poor can be reduced compared to Comparative Example 2.

[0085] <<A.6. Summary of the Embodiment>> As described above, according to this embodiment, since the screw component 5 is fixed to the drive circuit board 400 without providing an opening in the drive circuit board 400, the possibility of the drive circuit board 400 functioning as an antenna can be reduced, and high-quality images can be formed in the printing process.

[0086] Furthermore, according to this embodiment, since the nut 52 is equipped with a bottom plate portion 500, the intrusion of adhesive BD into the screw hole 500K can be suppressed, and the possibility of poor fastening between the nut 52 and the screw 51 can be reduced.

[0087] Furthermore, according to this embodiment, when the drive signal generation unit 4 and the screw component 5 are viewed in plan in the Z2 direction, the screw component 5 is positioned to overlap with the transistors TrH and TrL. Therefore, the heat emitted from transistors TrH and TrL can be dissipated to the housing 800 via the screw component 5. As a result, according to this embodiment, it is possible to suppress the overheating of transistors TrH and TrL, and to suppress distortion of the drive signal Com waveform and other issues that occur when transistors TrH and TrL overheat.

[0088] Furthermore, according to this embodiment, since the screw component 5 is fixed to the drive circuit board 400 without providing an opening in the drive circuit board 400, when the drive signal generation unit 4 and the screw component 5 are viewed in plan in the Z2 direction, it becomes possible to position the drive signal generation circuit 40 at a position that overlaps with the screw component 5, and it also becomes possible to position the wiring 402L at a position that overlaps with the screw component 5. In other words, according to this embodiment, compared to the configuration in which an opening 400K is provided in the drive circuit board 400Z as in proportionality 1, it becomes possible to increase the degree of freedom in positioning the drive signal generation circuit 40 and the degree of freedom in positioning the wiring 402L in the wiring layer 402. For this reason, according to this embodiment, it becomes possible to miniaturize the drive signal generation unit 4 compared to proportionality 1, and furthermore, it becomes possible to miniaturize the inkjet printer 1.

[0089] <<B. Modified Example>> Each of the above forms can be variously modified. Specific modification modes are exemplified below. Two or more modes arbitrarily selected from the following exemplifications can be appropriately combined within a range where they do not conflict with each other. In the modified examples exemplified below, for elements whose actions and functions are equivalent to those in the embodiments, the reference signs referred to in the above description are reused, and the detailed description of each is appropriately omitted.

[0090] <<B.1. Modified Example 1>> In the above-described embodiment, when the drive signal generation unit 4 and the screw component 5 are viewed in plan in the Z2 direction, the embodiment in which the transistor TrH and the transistor TrL are arranged at positions overlapping the screw component 5 has been exemplified and described. However, the present invention is not limited to such an embodiment. For example, when the drive signal generation unit 4 and the screw component 5 are viewed in plan in the Z2 direction, a smoothing circuit 44 may be arranged at a position overlapping the screw component 5. Also, when the drive signal generation unit 4 and the screw component 5 are viewed in plan in the Z2 direction, one or more electronic components included in the drive signal generation circuit 40 may be arranged at a position overlapping the screw component 5.

[0091] Even in Modified Example 1, heat generated from the electronic components constituting the drive signal generation circuit 40 can be radiated to the housing 800 through the screw component 5.

[0092] <<B.2. Modified Example 2>> In the above-described embodiment and Modified Example 1, when the drive signal generation unit 4 and the screw component 5 are viewed in plan in the Z2 direction, the embodiment in which the drive signal generation circuit 40 is arranged at a position overlapping the screw component 5 has been exemplified and described. However, the present invention is not limited to such an embodiment. For example, when the drive signal generation unit 4 and the screw component 5 are viewed in plan in the Z2 direction, the drive signal generation circuit 40 may be arranged at a position not overlapping the screw component 5.

[0093] FIG. 13 is a cross-sectional view showing an example of the configuration of an inkjet printer according to Modified Example 2.

[0094] As shown in Figure 13, the inkjet printer according to the modified example 2 is configured similarly to the inkjet printer 1 according to the embodiment, except that it is equipped with a drive signal generation unit 4B instead of the drive signal generation unit 4. The drive signal generation unit 4B is configured similarly to the drive signal generation unit 4 according to the embodiment, except that when the drive signal generation unit 4B and the screw component 5 are viewed in a plan view in the Z2 direction, the drive signal generation circuit 40 is positioned so as not to overlap with the screw component 5.

[0095] Figure 14 is a plan view of the drive signal generation unit 4B according to the modified example 2, as seen in the Z2 direction.

[0096] As shown in Figure 14, when the drive signal generation unit 4B and the screw component 5 are viewed in plan in the Z2 direction, the screw component 5 is positioned so as not to overlap with the drive signal generation circuit 40. Also, when the drive signal generation unit 4B and the screw component 5 are viewed in plan in the Z2 direction, the screw component 5 is positioned so as to overlap with the wiring 402L.

[0097] Furthermore, when the drive signal generation unit 4B and screw component 5 are viewed in plan in the Z2 direction, the screw component 5 is provided in the vicinity of transistors TrH and TrL. More specifically, in modified example 2, when the drive signal generation unit 4B and screw component 5 are viewed in plan in the Z2 direction, transistor TrH and screw component 5 are provided such that the shortest distance dNH from transistor TrH to screw component 5 is shorter than the shortest distance dTH from transistor TrH to the outer circumference of the drive circuit board 400. Also, when the drive signal generation unit 4B and screw component 5 are viewed in plan in the Z2 direction, transistor TrH and screw component 5 are provided such that the shortest distance dNL from transistor TrL to screw component 5 is shorter than the shortest distance dTL from transistor TrL to the outer circumference of the drive circuit board 400.

[0098] In the modified example 2, the heat generated from transistors TrH and TrL can be dissipated to the housing 800 via the screw component 5.

[0099] <<B.3. Modified Example 3>> In the above-described embodiments and Modified Examples 1 and 2, when the drive signal generation unit 4 and the screw component 5 are viewed in a plan view in the Z2 direction, the wiring 402L is arranged at a position overlapping the screw component 5 and has been described by way of example. However, the present invention is not limited to such an aspect. For example, when the drive signal generation unit 4 and the screw component 5 are viewed in a plan view in the Z2 direction, the wiring 402L may be arranged at a position not overlapping the screw component 5.

[0100] <<B.4. Modified Example 4>> In the above-described embodiments and Modified Examples 1 to 3, the case where the inkjet printer 1 is a serial printer has been assumed. However, the present invention is not limited to such an aspect. The inkjet printer 1 may be a so-called line printer in which a plurality of nozzles N are provided in the head unit 3 so as to extend wider than the width of the recording paper PP. In this case, the head unit 3 does not reciprocate inside the housing 100, and the relative positional relationship between the head unit 3 and the housing 100 does not change.

[0101] <<B.5. Modified Example 5>> In the above-described embodiments and Modified Examples 1 to 4, the case where the drive signal generation unit 4 is provided separately from the head unit 3 has been described by way of example. However, the present invention is not limited to such an aspect. The drive signal generation unit 4 may be mounted on the head unit 3. In this case, the inkjet printer 1 including the head unit 3 and the drive signal generation unit 4 is preferably the line printer described in Modified Example 4.

[0102] FIG. 15 is a functional block diagram showing an example of the configuration of an inkjet printer 1C according to Modified Example 5.

[0103] As shown in FIG. 15, the inkjet printer 1C differs from the inkjet printer 1 according to the embodiment in that it includes a head unit 3C instead of the head unit 3 and a conveyance unit 9C instead of the conveyance unit 9. The head unit 3C differs from the head unit 3 according to the embodiment in that it includes a drive signal generation unit 4 in addition to the supply circuit 31 and the head unit 32. The conveyance unit 9C differs from the conveyance unit 9 according to the embodiment in that it conveys the recording paper PP but does not have the function of conveying the carriage 110 on which the head unit 3 is mounted. Specifically, the conveyance unit 9C differs from the conveyance unit 9 according to the embodiment in that it does not include a carriage conveyance motor 91, a carriage guide shaft 96, and a belt 97.

[0104] Also in Modification 5, as in the embodiment, since the screw component 5 is fixed to the drive circuit board 400 without providing an opening in the drive circuit board 400, the possibility that the drive circuit board 400 functions as an antenna can be reduced, and high-quality image formation is possible in the printing process.

[0105] <<C. Supplementary Note>> Aspects related to the above description are appended below. For ease of understanding of each aspect, hereinafter, the reference signs in the drawings are appended in parentheses for convenience, but this is not intended to limit the present invention to the illustrated aspects.

[0106] <<Supplementary Note 1>> The inkjet printer 1 according to Supplementary Note 1 includes a discharge unit D that is driven by a drive signal Com to discharge ink, a drive circuit board 400 on which a drive signal generation circuit 40 that generates the drive signal Com is disposed, a housing 800 that houses the drive circuit board 400, and a screw component 5 that connects the drive circuit board 400 and the housing 800. The drive circuit board 400 has a non-opening formation region 400N in which no opening is formed, and the screw component 5 is fixed to the drive circuit board 400 in the non-opening formation region 400N.

[0107] According to Appendix 1, since the drive circuit board 400 and the housing 800 are connected by screw parts 5 without providing openings such as screw holes in the drive circuit board 400, the generation of noise caused by openings provided in the drive circuit board 400 functioning as antennas can be suppressed, and the deterioration of print quality caused by such noise can be suppressed.

[0108] <<Note 2>> The inkjet printer 1 according to Appendix 2 is the inkjet printer 1 according to Appendix 1, characterized in that the drive signal generation circuit 40 comprises a plurality of electronic components including transistors TrH and TrL, and the screw component 5 is arranged near transistors TrH and TrL on the drive circuit board 400 when viewed in a direction perpendicular to the drive circuit board 400.

[0109] According to Appendix 2, since the screw component 5 is positioned near transistors TrH and TrL, the heat generated in transistors TrH and TrL can be dissipated through the screw component 5.

[0110] <<Note 3>> The inkjet printer 1 according to Appendix 3 is the inkjet printer 1 according to Appendix 1 or Appendix 2, characterized in that the drive signal generation circuit 40 comprises a plurality of electronic components including transistors TrH and TrL, and the screw component 5 is positioned between transistors TrH and TrL on the drive circuit board 400 when viewed in a direction perpendicular to the drive circuit board 400.

[0111] According to Appendix 3, since the screw component 5 is positioned between transistors TrH and TrL, the heat generated in transistors TrH and TrL can be dissipated through the screw component 5.

[0112] <<Note 4>> The inkjet printer 1 according to Appendix 4 is the inkjet printer 1 according to Appendix 1 to Appendix 3, wherein the drive circuit board 400 comprises an upper board surface 4001 on which screw components 5 are arranged, and a lower board surface 4002 on the opposite side of the upper board surface 4001 on which a drive signal generation circuit 40 is arranged, and the drive signal generation circuit 40 and the screw components 5 overlap when viewed in a direction perpendicular to the drive circuit board 400.

[0113] According to Appendix 4, since the screw component 5 is fixed to the drive circuit board 400 without providing an opening in the drive circuit board 400, the drive signal generation circuit 40 can be arranged on the drive circuit board 400 without being restricted by the screw component 5.

[0114] <<Note 5>> The inkjet printer 1 according to Appendix 5 is the same as the inkjet printer 1 according to Appendix 4, wherein the drive circuit board 400 is a multilayer board including a wiring layer 402 provided between the upper board surface 4001 and the lower board surface 4002, and the wiring 402L provided on the wiring layer 402, the drive signal generation circuit 40 and the screw component 5 overlap when viewed in a direction perpendicular to the upper board surface 4001.

[0115] According to Appendix 5, since the screw component 5 is fixed to the drive circuit board 400 without providing an opening in the drive circuit board 400, the wiring 402L can be arranged inside the drive circuit board 400 without being restricted by the screw component 5.

[0116] <<Note 6>> The inkjet printer 1 according to Appendix 6 is the inkjet printer 1 according to Appendix 1 to Appendix 5, wherein the screw part 5 comprises a screw 51 fixed to the housing 800 and a nut 52 fixed to the drive circuit board 400 in the non-opening region 400N and fastened with the screw 51, the nut 52 comprises a screw hole 500K into which the screw 51 is inserted and a bottom plate portion 500 located between the screw hole 500K and the non-opening region 400N when the nut 52 is fixed to the non-opening region 400N, the bottom plate portion 500 comprises an upper surface 5001 that constitutes the bottom surface of the screw hole 500K and a lower surface 5002 on the opposite side of the upper surface 5001 and fixed to the non-opening region 400N.

[0117] According to Appendix 6, the screw component 5 can be fixed to the drive circuit board 400 without providing an opening in the drive circuit board 400.

[0118] <<Note 7>> The inkjet printer 1 according to Appendix 7 is the inkjet printer 1 according to Appendix 1 to Appendix 6, wherein the drive circuit board 400 comprises an upper board surface 4001 on which screw components 5 are arranged, and a lower board surface 4002 on the opposite side of the upper board surface 4001 on which a drive signal generation circuit 40 is arranged, and is a multilayer board including a wiring layer 402 provided between the upper board surface 4001 and the lower board surface 4002, and is characterized in that, when viewed in a direction perpendicular to the upper board surface 4001, the wiring 402L provided on the wiring layer 402 and the screw components 5 overlap.

[0119] According to Appendix 7, since the screw component 5 is fixed to the drive circuit board 400 without providing an opening in the drive circuit board 400, the wiring 402L can be arranged inside the drive circuit board 400 without being restricted by the screw component 5. [Explanation of Symbols]

[0120] 1...Inkjet printer, 2...Control unit, 3...Head unit, 4...Drive signal generation unit, 5...Screw part, 9...Transport unit, 31...Supply circuit, 32...Head section, 51...Screw, 52...Nut, 40...Drive signal generation circuit, 41...Integrated circuit, 43...Amplification circuit, 44...Smoothing circuit, 400...Drive circuit board, 400N...Aperture non-formed area, 402...Wiring layer, 402L...Wiring, 500...Bottom plate section, 500K...Screw hole, 800...Housing, 800K...Opening, 4001...Upper board surface, 4002...Lower board surface, 5001...Upper side surface, 5002...Lower side surface, BD...Adhesive, D...Ejection section, TrH...Transistor, TrL...Transistor.

Claims

1. A dispensing unit that is driven by a drive signal to dispense liquid, A circuit board on which a drive circuit that generates the aforementioned drive signal is arranged, A housing for the aforementioned circuit board, Screw components for connecting the circuit board and the housing, Equipped with, The circuit board has a substrate region in which no openings are formed, The screw component is fixed to the circuit board in the substrate region. A liquid dispensing device characterized by the following features.

2. The drive circuit comprises a plurality of electronic components, including a first electronic component and a second electronic component. The screw component is positioned in the vicinity of the first and second electronic components on the circuit board when viewed in a direction perpendicular to the circuit board. The liquid dispensing device according to claim 1, characterized in that...

3. The drive circuit comprises a plurality of electronic components, including a first electronic component and a second electronic component. The screw component is positioned between the first electronic component and the second electronic component on the circuit board, when viewed in a direction perpendicular to the circuit board. The liquid dispensing device according to claim 1, characterized in that...

4. The aforementioned circuit board is The first substrate surface on which the screw component is arranged, The substrate comprises a second substrate surface, which is the surface opposite to the first substrate surface on which the circuit board is arranged, When viewed in a direction perpendicular to the first substrate surface, the drive circuit and the screw component overlap. The liquid dispensing device according to claim 1, characterized in that...

5. The circuit board is a multilayer board including a wiring layer provided between the first substrate surface and the second substrate surface, When viewed in a direction perpendicular to the first substrate surface, the wiring provided in the wiring layer, the drive circuit, and the screw component overlap. The liquid dispensing device according to claim 4, characterized in that

6. The aforementioned screw part is Screws that are fixed to the aforementioned housing, The substrate region includes a nut that is fixed to the circuit board and fastened with the screw, The aforementioned nut is The screw hole into which the aforementioned screw is inserted, When the nut is fixed to the substrate area, the system includes a bottom plate portion located between the screw hole and the substrate area, The aforementioned bottom plate portion is The first surface that constitutes the bottom surface of the screw hole, The material comprises a second surface which is the surface opposite to the first surface and is fixed to the substrate region, The liquid dispensing device according to claim 1, characterized in that...

7. The aforementioned circuit board is The first substrate surface on which the screw component is arranged, The surface opposite to the first substrate surface, the second substrate surface on which the circuit board is arranged, A multilayer substrate comprising a wiring layer provided between the first substrate surface and the second substrate surface, When viewed in a direction perpendicular to the first substrate surface, the wiring provided in the wiring layer and the screw component overlap. A liquid dispensing device according to any one of claims 1 to 6, characterized in that

8. A dispensing unit that is driven by a drive signal to dispense liquid, A circuit board on which a drive circuit that generates the aforementioned drive signal is arranged, Screw components for connecting the circuit board and the housing that houses the circuit board, Equipped with, The circuit board has a substrate region in which no openings are formed, The screw component is fixed to the circuit board in the substrate region. A head unit characterized by the following features.

9. The drive circuit comprises a plurality of electronic components, including a first electronic component and a second electronic component. The screw component is positioned in the vicinity of the first and second electronic components on the circuit board when viewed in a direction perpendicular to the circuit board. The head unit according to claim 8, characterized in that

10. The drive circuit comprises a plurality of electronic components, including a first electronic component and a second electronic component. The screw component is positioned between the first electronic component and the second electronic component on the circuit board, when viewed in a direction perpendicular to the circuit board. The head unit according to claim 8, characterized in that

11. The aforementioned circuit board is The first substrate surface on which the screw component is arranged, The substrate comprises a second substrate surface, which is the surface opposite to the first substrate surface on which the circuit board is arranged, When viewed in a direction perpendicular to the first substrate surface, the drive circuit and the screw component overlap. The head unit according to claim 8, characterized in that

12. The circuit board is a multilayer board including a wiring layer provided between the first substrate surface and the second substrate surface, When viewed in a direction perpendicular to the first substrate surface, the wiring provided in the wiring layer, the drive circuit, and the screw component overlap. The head unit according to claim 11, characterized in that...

13. The aforementioned screw part is Screws that are fixed to the aforementioned housing, The substrate region includes a nut that is fixed to the circuit board and fastened with the screw, The aforementioned nut is The screw hole into which the aforementioned screw is inserted, When the nut is fixed to the substrate area, the system includes a bottom plate portion located between the screw hole and the substrate area, The aforementioned bottom plate portion is The first surface that constitutes the bottom surface of the screw hole, The material comprises a second surface which is the surface opposite to the first surface and is fixed to the substrate region, The head unit according to claim 8, characterized in that

14. The aforementioned circuit board is The first substrate surface on which the screw component is arranged, The surface opposite to the first substrate surface, the second substrate surface on which the circuit board is arranged, A multilayer substrate comprising a wiring layer provided between the first substrate surface and the second substrate surface, When viewed in a direction perpendicular to the first substrate surface, the wiring provided in the wiring layer and the screw component overlap. A head unit according to any one of claims 8 to 13, characterized in that...

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