Liquid ejection device and cooling unit

Abstract

A liquid ejection apparatus and a cooling unit capable of reducing the possibility of short circuit in a head driving module due to ink mist generated from a liquid ejection module are provided. The liquid ejection apparatus includes: a head driving module (10-1, 10-2); a liquid ejection module (20-1) that ejects ink to a medium based on a driving signal from the head driving module (10-1); a liquid ejection module (20-2) that ejects ink to a medium based on a driving signal from the head driving module (10-2); a suction fan and an exhaust fan that generate an air flow; a first air tunnel (WT1) that guides the air flow to a first path; and a second air tunnel (WT2) that guides the air flow to a second path different from the first path, the head driving module (10-1) is disposed inside the first air tunnel (WT1), the head driving module (10-2) is disposed inside the second air tunnel (WT2), and the liquid ejection modules (20-1, 20-2) are disposed outside the first air tunnel (WT1) and the second air tunnel (WT2).

Description

Technical Field

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

[0002] In liquid ejection devices that form images on a medium by ejecting liquids such as ink from a head, high ejection stability is required to form high-resolution images. If the distance from the drive circuit that drives the head to the head increases, the influence of inductance caused by wiring increases, posing a risk of decreased ejection stability. Therefore, as shown in Patent Document 1, a configuration in which the drive circuit is positioned directly above the head is known.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-138356

[0004] In such liquid ejection devices, the temperature of the drive circuit becomes extremely high because the integrated circuits, FETs, coils, and other electronic components constituting the drive circuit are densely packed within a limited area at the top of the head. Therefore, as shown in Patent Document 1, the drive circuit is generally cooled by air cooling. However, if an airflow is generated directly above the head, it can sometimes swirl up the ink mist that floats with the ejected ink. If the ink mist swirls up and adheres to the drive circuit, there is a risk of short circuits occurring within the drive circuit. Summary of the Invention

[0005] The liquid ejection device includes: a first drive circuit for generating a first drive signal; a second drive circuit for generating a second drive signal; a first ejection section for ejecting liquid to a medium based on the first drive signal; a second ejection section for ejecting liquid to a medium based on the second drive signal; an air supply section for generating airflow; a first wind tunnel for guiding the airflow to a first path; and a second wind tunnel for guiding the airflow to a second path different from the first path. The first drive circuit is disposed inside the first wind tunnel, the second drive circuit is disposed inside the second wind tunnel, and the first ejection section and the second ejection section are disposed outside the first wind tunnel and the second wind tunnel, respectively.

[0006] The cooling unit is installed on the first head unit and the second head unit. The first head unit has a first drive circuit that generates a first drive signal and a first ejector that sprays liquid onto a medium based on the first drive signal. The second head unit has a second drive circuit that generates a second drive signal and a second ejector that sprays liquid onto a medium based on the second drive signal. The cooling unit includes: an air supply section that generates airflow; a first wind tunnel that guides the airflow to a first path; and a second wind tunnel that guides the airflow to a second path different from the first path. The first drive circuit is disposed inside the first wind tunnel, the second drive circuit is disposed inside the second wind tunnel, and the first ejector and the second ejector are disposed outside the first wind tunnel and the second wind tunnel. Attached Figure Description

[0007] Figure 1 This is a diagram showing the general structure of a liquid ejection device.

[0008] Figure 2 This is a diagram showing the general structure of the head unit.

[0009] Figure 3 This is a diagram showing an example of the signal waveform of the driving signal.

[0010] Figure 4 This is a diagram illustrating the functional structure of the drive signal selection circuit.

[0011] Figure 5 This is a diagram illustrating an example of the decoder's decoded content.

[0012] Figure 6 This is a diagram illustrating an example of the configuration of a selection circuit.

[0013] Figure 7 This is a diagram used to illustrate the operation of the drive signal selection circuit.

[0014] Figure 8 This is a diagram showing the structure of the liquid ejection module.

[0015] Figure 9 This is a diagram showing an example of the structure of the ejection module.

[0016] Figure 10 It is Figure 9 The cross-sectional view shown is taken when line Aa cuts through the ejection module.

[0017] Figure 11 This is a perspective view showing an example of the structure of a head-driven module.

[0018] Figure 12 This is a diagram showing an example of the installation of the drive signal output circuit on the third substrate included in the drive circuit section.

[0019] Figure 13 This is a diagram showing an example of the positional relationship between the heat sink, the drive signal output circuit, and the third substrate.

[0020] Figure 14 This is a diagram illustrating an example of the structure of a cooling unit.

[0021] Figure 15 This is a front view showing the head unit and cooling unit.

[0022] Figure 16 This is a side view showing the head unit and cooling unit.

[0023] Figure 17 This is a perspective view showing the head unit and cooling unit.

[0024] Figure 18 This is a diagram illustrating an example of the structure of the cooling unit involved in the modified example.

[0025] Explanation of reference numerals in the attached figures

[0026] 1…Liquid ejection device, 2…Control unit, 3…Liquid container, 4…Conveying unit, 5, 5-1, 5-2, 5-3…Head unit, 6…Cooling unit, 10, 10-1, 10-2, 10-3…Head drive module, 20, 20-1, 20-2, 20-3…Liquid ejection module, 23, 23-1~23-m…Ejection module, 30, 30-1, 30-2, 30-3…Wiring component, 31…Housing, 33…Collection base plate, 34…Flow path structure, 35…Head base plate, 37…Distribution flow path, 39…Fixing plate, 41…Conveyor motor, 42…Conveyor roller, 50-1~50-m…Drive signal output circuit, 52a, 52b, 52c…Drive circuit, 53…Reference voltage output Output circuit, 60…piezoelectric element, 100…control circuit, 120…conversion circuit, 200…drive signal selection circuit, 201…integrated circuit, 210…selection control circuit, 212…shift register, 214…latch circuit, 216…decoder, 220…recovery circuit, 230…selection circuit, 232a, 232b, 232c…inverter, 234a, 234b, 234c…conversion gate, 311…opening, 313…substrate insertion part, 315…holding member, 330…connection part, 341…inlet part, 343…through hole, 351…opening, 352, 353, 355…cutout, 371…opening, 373…inlet part, 388…wiring member, 39… 1…Opening, 600…Ejection section, 610…Vibrating plate, 611…Lead electrode, 620…Flexible substrate, 621…Sealing film, 622…Fixed substrate, 623…Nozzle plate, 623a…Liquid jet surface, 630…Connecting plate, 641…Protective substrate, 642…Flow path forming substrate, 643…Through hole, 644…Protective space, 660…Housing, 661…Inlet path, 662…Connection port, 665…Recess, 700, 701…Channel, Adp, Bdp, Cdp…Trapezoidal waveform, B1…First circuit board, B2…Second circuit board, B3…Third circuit board, CB, CB1, CB2…Pressure chamber, CLT…Coolant tank, CN1…First connector, CN2…Second connector Connector, CN3… third connector, CN4… fourth connector, CN5… fifth connector, COMA, COMB, COMA1~COMAm, COMB1~COMBm, COMC1~COMCm… drive signals, CP… electrolytic capacitor, dA1, dB1, dC1… basic drive signals, DATA… data signals, dDATA… basic data signals, DRV, DRV1~DRV6… drive circuit section, FC… wiring component, FET… field effect transistor, FNi… intake fan, FNo… exhaust fan, Fns… fins, HE… heat exchange section, HS… housing, HS2… heat sink, HS21… first plate component, HS22… second plate component,HS23…First connecting member, IC…Integrated circuit, IP…Image information signal, LAT, LAT1~LATm…Latch signal, Ln1, Ln2…Nozzle array, M1…First face, M2…Second face, MN, MN1, MN2…Manifold, N, N1, N2…Nozzle, P…Medium, RA, RA1, RA2…Supply connection path, RB, RB1, RB2…Supply connection path, RC…Coil, RD…Radiator, RK1, RK2…Pressure chamber connection path, RR, RR1, RR2…Nozzle connection path, RVi1, RVi2, RVi3…Intake Side adjustment section, RVO1, RVO2, RVO3…exhaust side adjustment section, RX, RX1, RX2…connecting circuit, S1, S2, S3…selection signal, SCK, SCK1~SCKm…clock signal, SI, SI1~SIm…printed data signal, Su1…flow path board, Su2…flow path board, T…cycle, VBS, VBS1~VBSm…reference voltage signal, Vc…voltage, VOUT…drive signal, WT1…first wind tunnel, WT2…second wind tunnel, WT3…third wind tunnel, WTi…common intake wind tunnel, WT0…common exhaust wind tunnel. Detailed Implementation

[0027] The preferred embodiments of this disclosure will now be described using the accompanying drawings. The drawings are for ease of explanation. It should be noted that the embodiments described below are not intended to unduly limit the scope of this disclosure as defined in the claims. Furthermore, not all of the components described below are essential elements of this disclosure.

[0028] 1. Composition of the liquid ejection device

[0029] Figure 1 This is a diagram showing the general configuration of the liquid ejection device 1. (See diagram below.) Figure 1 As shown, the liquid ejection device 1 is a so-called line-mode inkjet printer that forms a desired image on the medium P by ejecting ink, an example of liquid, from the medium P conveyed by the transport unit 4 at a desired timing. Here, in the following description, the direction in which the medium P is transported is sometimes referred to as the transport direction, and the width direction of the transported medium P is referred to as the main scanning direction.

[0030] like Figure 1 As shown, the liquid dispensing device 1 includes a control unit 2, a liquid container 3, a conveying unit 4, multiple head units 5, a cooling unit 6, and a housing HS. The housing HS constitutes the outer casing of the liquid dispensing device 1, and internally houses the control unit 2, the liquid container 3, the conveying unit 4, the multiple head units 5, and the cooling unit 6. However, it is also possible that a portion of the control unit 2, the liquid container 3, the conveying unit 4, the multiple head units 5, and the cooling unit 6 are disposed outside the housing HS or protrude from the inside of the housing HS to the outside.

[0031] The control unit 2 includes processing circuits such as a CPU (Central Processing Unit) and an FPGA (Field Programmable Gate Array), and storage circuits such as semiconductor memory. Based on image data supplied from an external device such as a host computer (not shown) located outside the liquid ejection device 1, the control unit 2 outputs signals to control various elements of the liquid ejection device 1.

[0032] The liquid container 3 stores one or more liquids that are supplied to the head unit 5. For example, the liquid container 3 stores ink that is supplied to the head unit 5. Specifically, the liquid container 3 stores inks of multiple colors that are sprayed onto the medium P, such as black, cyan, magenta, yellow, red, gray, etc. Of course, the liquid container 3 may only store black ink, or it may store liquids other than ink.

[0033] The conveying unit 4 includes a conveying motor 41 and a conveying roller 42. A conveying control signal output from the control unit 2 is input to the conveying unit 4. Then, the conveying motor 41 operates based on the input conveying control signal, and as the conveying motor 41 operates, the conveying roller 42 is driven to rotate, thereby conveying the medium P along the conveying direction.

[0034] Multiple head units 5 each have a head drive module 10 and a liquid ejection module 20. An image information signal IP output from the control unit 2 is input to the head unit 5, and ink stored in the liquid container 3 is supplied. Then, based on the image information signal IP input from the control unit 2, the head drive module 10 controls the operation of the liquid ejection module 20, and the liquid ejection module 20 ejects the ink supplied from the liquid container 3 to the medium P according to the control of the head drive module 10.

[0035] Furthermore, the liquid ejection modules 20 of each of the multiple head units 5 are arranged along the main scanning direction such that they can eject ink over the entire width of the transported medium P, extending beyond the width of the medium P. Thus, the liquid ejection device 1 constitutes a line-mode inkjet printer. It should be noted that the liquid ejection device 1 is not limited to line-mode inkjet printers.

[0036] The cooling unit 6 has a channel 700 disposed inside the housing HS, an intake fan FNi and an exhaust fan FNo disposed inside the channel 700. The cooling unit 6 cools the head drive module 10 disposed within the channel 700. The channel 700 has Figure 1The intake and exhaust ports (not shown) communicate with the outside of the housing HS. Cooling control signals are input from the control unit 2 to the intake fan FNi and exhaust fan FNo. The intake fan FNi and exhaust fan FNo then operate based on the input cooling control signals, generating airflow within the channel 700. It should be noted that a portion of the channel 700, including the intake and exhaust ports, may also protrude outside the housing HS.

[0037] Next, the general structure of head unit 5 will be explained. Figure 2 This is a diagram showing the general structure of head unit 5. (See diagram for example.) Figure 2 As shown, the head unit 5 has a head drive module 10 and a liquid ejection module 20. Furthermore, in the head unit 5, the head drive module 10 and the liquid ejection module 20 are electrically connected by one or more wiring components 30.

[0038] The wiring component 30 is a flexible component used for the electrical connector drive module 10 and the liquid ejection module 20, such as a flexible printed circuit board (FPC).

[0039] The head drive module 10 includes a control circuit 100, drive signal output circuits 50-1 to 50-m, and a conversion circuit 120.

[0040] The control circuit 100 includes a CPU, FPGA, etc. Image information signal IP output from the control unit 2 is input to the control circuit 100. Based on the input image information signal IP, the control circuit 100 outputs signals to control various elements of the head unit 5.

[0041] The control circuit 100 generates a basic data signal dDATA for controlling the operation of the liquid ejection module 20 based on the image information signal IP, and outputs it to the conversion circuit 120. The conversion circuit 120 converts the basic data signal dDATA into a differential signal such as LVDS (Low Voltage Differential Signaling), and outputs it as the data signal DATA to the liquid ejection module 20. It should be noted that the conversion circuit 120 can also convert the basic data signal dDATA into a differential signal using a high-speed transmission method other than LVDS, such as LVPECL (Low Voltage Positive Emitter Coupled Logic) or CML (Current Mode Logic), and output it as the data signal DATA to the liquid ejection module 20. Alternatively, part or all of the basic data signal dDATA can be output as a single-ended data signal DATA to the liquid ejection module 20.

[0042] Additionally, the control circuit 100 outputs basic drive signals dA1, dB1, and dB1 to the drive signal output circuit 50-1. The drive signal output circuit 50-1 includes drive circuits 52a, 52b, and 52c. The basic drive signal dA1 is input to drive circuit 52a. Drive circuit 52a performs digital-to-analog conversion on the input basic drive signal dA1, amplifies it using a D-stage amplifier to generate drive signal COMA1, and outputs it to the liquid ejection module 20. The basic drive signal dB1 is input to drive circuit 52b. Drive circuit 52b performs digital-to-analog conversion on the input basic drive signal dB1, amplifies it using a D-stage amplifier to generate drive signal COMB1, and outputs it to the liquid ejection module 20. The basic drive signal dB1 is input to drive circuit 52c. Drive circuit 52c performs digital-to-analog conversion on the input basic drive signal dB1, amplifies it using a D-stage amplifier to generate drive signal COMC1, and outputs it to the liquid ejection module 20.

[0043] Here, each of the driving circuits 52a, 52b, and 52c only needs to be able to generate driving signals COMA1, COMB1, and COMC1 by amplifying the waveform defined by each of the input basic driving signals dA1, dB1, and dC1. It can also replace the D-level amplifier circuit, or include A-level, B-level, or AB-level amplifier circuits in addition to the D-level amplifier circuit. Furthermore, each of the basic driving signals dA1, dB1, and dC1 only needs to be able to define the waveform of the corresponding driving signals COMA1, COMB1, and COMC1, and can also be an analog signal.

[0044] Additionally, the drive signal output circuit 50-1 includes a reference voltage output circuit 53. The reference voltage output circuit 53 generates a reference voltage signal VBS1 that indicates a constant potential of the reference potential of the piezoelectric element 60 (described later) in the liquid ejection module 20, and outputs it to the liquid ejection module 20. This reference voltage signal VBS1 can be, for example, a ground potential, or a constant potential such as 5.5V or 6V. Here, a constant potential refers to a potential that can be considered approximately constant, taking into account variations caused by errors such as potential variations due to the operation of peripheral circuits, potential variations due to deviations in circuit components, and potential variations due to the temperature characteristics of circuit components.

[0045] The drive signal output circuits 50-2 to 50-m differ only in the input and output signals; they have the same configuration as drive signal output circuit 50-1. Specifically, drive signal output circuit 50-j (j being any one of 1 to m) includes circuits equivalent to drive circuits 52a, 52b, and 52c, and a circuit equivalent to reference voltage output circuit 53. Based on the basic drive signals dAj, dBj, and dCj input from control circuit 100, it generates drive signals COMAj, COMBj, COMCj, and a reference voltage signal VBSj, which are then output to the liquid ejection module 20.

[0046] The liquid ejection module 20 has a recovery circuit 220 and ejection modules 23-1 to 23-m.

[0047] The restoration circuit 220 restores the data signal DATA into a single-ended signal and separates it into signals corresponding to each of the ejection modules 23-1 to 23-m, and outputs them to the corresponding ejection modules 23-1 to 23-m.

[0048] Specifically, the recovery circuit 220 recovers and separates the data signal DATA, thereby generating a clock signal SCK1, a printing data signal SI1, and a latch signal LAT1 corresponding to the ejection module 23-1, and outputs them to the ejection module 23-1. Additionally, the recovery circuit 220 recovers and separates the data signal DATA, thereby generating a clock signal SCKj, a printing data signal SIj, and a latch signal LATj corresponding to the ejection module 23-j, and outputs them to the ejection module 23-j.

[0049] As described above, the restoration circuit 220 restores the data signal DATA of the differential signal output by the head drive module 10, and separates the restored signal into signals corresponding to the ejection modules 23-1 to 23-m. Thus, the restoration circuit 220 generates clock signals SCK1 to SCKm, printing data signals SI1 to SIm, and latch signals LAT1 to LATm corresponding to each ejection module among the ejection modules 23-1 to 23-m, and outputs them to the corresponding ejection modules 23-1 to 23-m. It should be noted that any one of the clock signals SCK1 to SCKm, printing data signals SI1 to SIm, and latch signals LAT1 to LATm output by the restoration circuit 220 corresponding to each ejection module among the ejection modules 23-1 to 23-m can also be a shared signal for all ejection modules 23-1 to 23-m.

[0050] Here, from the perspective that the recovery circuit 220 generates clock signals SCK1~SCKm, printing data signals SI1~SIm, and latch signals LAT1~LATm by recovering and separating the data signal DATA, the data signal DATA is a differential signal corresponding to the clock signals SCK1~SCKm, printing data signals SI1~SIm, and latch signals LAT1~LATm. Furthermore, the basic data signal dDATA, which forms the basis of the data signal DATA, includes a signal corresponding to each of the clock signals SCK1~SCKm, printing data signals SI1~SIm, and latch signals LAT1~LATm. That is, the basic data signal dDATA includes signals that control the operation of the ejection modules 23-1~23-m of the liquid ejection module 20.

[0051] The ejection module 23-1 has a drive signal selection circuit 200 and a plurality of ejection sections 600. Each of the plurality of ejection sections 600 includes a piezoelectric element 60 as a drive element, which ejects ink to the medium P based on drive signals COMA1, COMB1, COMC1, etc. input to the ejection module 23-1.

[0052] Specifically, drive signals COMA1, COMB1, COMC1, a reference voltage signal VBS1, a clock signal SCK1, a printing data signal SI1, and a latch signal LAT1 are input to the ejection module 23-1. These drive signals COMA1, COMB1, COMC1, SCK1, SI1, and LAT1 are input to the drive signal selection circuit 200 of the ejection module 23-1. Based on the input clock signal SCK1, SI1, and LAT1, the drive signal selection circuit 200 selects or deselects each of the drive signals COMA1, COMB1, and COMC1, thereby generating a drive signal VOUT, which is supplied to one end of the piezoelectric element 60 of the corresponding ejection section 600. At this time, the reference voltage signal VBS1 is supplied to the other end of the piezoelectric element 60. Then, the piezoelectric element 60 is driven by the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBS1 supplied to the other end, thereby ejecting ink from the corresponding ejection section 600.

[0053] Similarly, the ejection module 23-j has a drive signal selection circuit 200 and a plurality of ejection sections 600. In addition, each of the plurality of ejection sections 600 includes a piezoelectric element 60 as a drive element, which ejects ink to the medium P based on drive signals COMAj, COMBj, COMCj, etc. input to the ejection module 23-j.

[0054] Specifically, drive signals COMAj, COMBj, COMCj, a quasi-voltage signal VBSj, a clock signal SCKj, a printing data signal SIj, and a latch signal LATj are input to the ejection module 23-j. These drive signals COMAj, COMBj, COMCj, SCKj, SIj, and LATj are input to the drive signal selection circuit 200 of the ejection module 23-j. Based on the input clock signal SCKj, SIj, and LATj, the drive signal selection circuit 200 selects or deselects each of the drive signals COMAj, COMBj, and COMCj, thereby generating a drive signal VOUT, which is supplied to one end of the piezoelectric element 60 of the corresponding ejection section 600. At this time, a reference voltage signal VBSj is supplied to the other end of the piezoelectric element 60. Furthermore, the piezoelectric element 60 is driven by the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBSj supplied to the other end, thereby ejecting ink from the corresponding ejection section 600.

[0055] In the liquid ejection device 1 of the first embodiment configured as described above, the control unit 2 controls the transport of the medium P via the transport unit 4 based on image data supplied by a host computer (not shown) or the like, and controls the liquid ejection module 20 of the head unit 5 to eject ink. Thus, the liquid ejection device 1 can drip a desired amount of ink at a desired location on the medium P, forming a desired image on the medium P.

[0056] Here, the ejection modules 23-1 to 23-m of the liquid ejection module 20 are identical in configuration, differing only in the input signals. Therefore, in the following description, unless it is necessary to distinguish between ejection modules 23-1 to 23-m, they are sometimes simply referred to as ejection module 23. Furthermore, in this case, the drive signals COMA1 to COMAm input to the ejection module 23 are sometimes referred to as drive signals COMA, drive signals COMB1 to COMBm as drive signals COMB, and drive signals COMC1 to COMCm as drive signals COMC. Similarly, the reference voltage signals VBS1 to VBSm are sometimes referred to as reference voltage signals VBS, the clock signals SCK1 to SCKm as clock signals SCK, the printing data signals SI1 to SIm as printing data signals SI, and the latch signals LAT1 to LATm as latch signals LAT.

[0057] Specifically, drive signals COMA, COMB, COMC, a reference voltage signal VBS, a clock signal SCK, a print data signal SI, and a latch signal LAT are input to the ejection module 23. These drive signals COMA, COMB, COMC, SCK, SI, and LAT are input to the drive signal selection circuit 200 of the ejection module 23. Based on the input clock signal SCK, SI, and LAT, the drive signal selection circuit 200 selects or deselects each of the drive signals COMA, COMB, and COMC, thereby generating a drive signal VOUT, which is then supplied to one end of the piezoelectric element 60 of the corresponding ejection section 600. At this time, a reference voltage signal VBS is supplied to the other end of the piezoelectric element 60. Furthermore, the piezoelectric element 60 is driven by the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBS supplied to the other end, thereby ejecting ink from the corresponding ejection section 600.

[0058] 2. Functional Composition of the Drive Signal Selection Circuit

[0059] Next, the configuration and operation of the drive signal selection circuit 200 of the ejection module 23 will be explained. When explaining the configuration and operation of the drive signal selection circuit 200 of the ejection module 23, an example of the signal waveforms contained in the drive signals COMA, COMB, and COMC input to the drive signal selection circuit 200 will first be explained.

[0060] Figure 3 This is a diagram showing an example of the signal waveforms for the drive signals COMA, COMB, and COMC. (See diagram for example.) Figure 3As shown, the drive signal COMA includes a trapezoidal waveform Adp, which is configured within a period T from the rise of the latch signal LAT to the next rise of the latch signal LAT. The trapezoidal waveform Adp is a signal waveform that ejects a predetermined amount of ink from the ejection section 600 corresponding to the piezoelectric element 60 by means of being supplied to one end of the piezoelectric element 60. The drive signal COMB includes a trapezoidal waveform Bdp configured within period T. This trapezoidal waveform Bdp is a signal waveform with a voltage amplitude smaller than that of the trapezoidal waveform Adp, and is a signal waveform that ejects a smaller amount of ink than a predetermined amount from the ejection section 600 corresponding to the piezoelectric element 60 by means of being supplied to one end of the piezoelectric element 60. The drive signal COMC includes a trapezoidal waveform Cdp configured within period T. The trapezoidal waveform Cdp is a signal waveform with a voltage amplitude smaller than that of trapezoidal waveforms Adp and Bdp. It is a signal waveform supplied to one end of the piezoelectric element 60, causing the ink near the nozzle orifice to vibrate to a degree that prevents ink from being ejected from the ejection section 600 corresponding to the piezoelectric element 60. This trapezoidal waveform Cdp, when supplied to the piezoelectric element 60, causes the ink near the nozzle orifice of the ejection section 600, including the piezoelectric element 60, to vibrate. Therefore, the risk of increased ink viscosity near the nozzle orifice is reduced.

[0061] That is, the drive signal COMA is a signal that drives the piezoelectric element 60 to eject ink, the drive signal COMB is a signal that drives the piezoelectric element 60 to eject ink, and the drive signal COMC is a signal that drives the piezoelectric element 60 to stop ejecting ink. When such a drive signal COMA is supplied to the piezoelectric element 60, the amount of ink ejected from the liquid ejection module 20 including the ejection module 23 is different from the amount of ink ejected from the liquid ejection module 20 including the ejection module 23 when the drive signal COMB is supplied to the piezoelectric element 60.

[0062] Furthermore, at the start and end timings of the trapezoidal waveforms Adp, Bdp, and Cdp, the voltage values ​​of Adp, Bdp, and Cdp are shared within the voltage Vc. That is, Adp, Bdp, and Cdp are signal waveforms that begin and end with voltage Vc, respectively.

[0063] In the following explanation, when the trapezoidal waveform Adp is supplied to one end of the piezoelectric element 60, the amount of ink ejected from the ejection portion 600 corresponding to the piezoelectric element 60 is sometimes referred to as a large amount. When the trapezoidal waveform Bdp is supplied to one end of the piezoelectric element 60, the amount of ink ejected from the ejection portion 600 corresponding to the piezoelectric element 60 is sometimes referred to as a small amount. Furthermore, when the trapezoidal waveform Cdp is supplied to one end of the piezoelectric element 60, the vibration of the ink near the nozzle opening to a degree that prevents it from being ejected from the ejection portion 600 corresponding to the piezoelectric element 60 is sometimes referred to as micro-vibration.

[0064] It should be noted that, in Figure 3 The example illustrates a case where each of the drive signals COMA, COMB, and COMC contains one trapezoidal waveform within a period T. However, each of the drive signals COMA, COMB, and COMC can also contain two or more consecutive trapezoidal waveforms within a period T. In this case, a signal specifying the switching timing of two or more trapezoidal waveforms is input to the drive signal selection circuit 200, and the ejection unit 600 ejects ink multiple times within a period T. Furthermore, the ink droplets ejected multiple times within a period T fall onto and combine with the medium P, thereby forming a single point on the medium P. This increases the grayscale level of the point formed on the medium P.

[0065] In contrast, in the liquid ejection device 1 shown in the first embodiment, the drive signals COMA, COMB, and COMC are described as signals containing one trapezoidal waveform within a period T. This shortens the period T at which points are formed on the medium P, increases the speed of image formation on the medium P, and increases the grayscale level of the points formed on the medium P by supplying the drive signals COMA, COMB, and COMC in parallel to the liquid ejection module 20. Here, the period T from the rise of the latch signal LAT to the next rise of the latch signal LAT is sometimes referred to as the point formation period for forming points of the desired size on the medium P.

[0066] It should be noted that the signal waveforms included in the drive signals COMA, COMB, and COMC are not limited to... Figure 3 The illustrated signal waveform can be varied depending on the type of ink ejected from the ejection section 600, the number of piezoelectric elements 60 driven by the drive signals COMA, COMB, and COMC, and the length of the wiring for propagating the drive signals COMA, COMB, and COMC. That is, Figure 2 The drive signals COMA1 to COMAm shown can each contain different signal waveforms, and similarly, the drive signals COMB1 to COMBm and the drive signals COMC1 to COMCm can each contain different signal waveforms.

[0067] Next, the configuration and operation of the drive signal selection circuit 200, which outputs the drive signal VOUT by setting each of the drive signals COMA, COMB, and COMC to be selected or not selected, will be explained. Figure 4 This is a diagram illustrating the functional configuration of the drive signal selection circuit 200. (See diagram for example.) Figure 4 As shown, the drive signal selection circuit 200 includes a selection control circuit 210 and multiple selection circuits 230.

[0068] The selection control circuit 210 receives a print data signal SI, a latch signal LAT, and a clock signal SCK. Furthermore, the selection control circuit 210 has a group of shift registers (S / R) 212, latch circuits 214, and decoders 216 corresponding to each of the n ejector sections 600. That is, the drive signal selection circuit 200 includes the same number of n shift registers 212, latch circuits 214, and decoders 216 as the number of ejector sections 600.

[0069] The printing data signal SI is a signal synchronized with the clock signal SCK, and includes 2-bit printing data [SIH, SIL] for defining the dot size formed by ink ejected from each of the n ejector sections 600 using any one of "Large Dot LD", "Small Dot SD", "No Ejection ND", and "Micro Vibration BSD". This printing data signal SI is stored in shift register 212 corresponding to the ejector section 600 in 2-bit increments of printing data [SIH, SIL].

[0070] Specifically, n shift registers 212 corresponding to the ejector section 600 are vertically connected to each other. The serially input printing data signal SI is sequentially transmitted to the subsequent stages of the vertically connected shift registers 212 according to the clock signal SCK. Then, by stopping the supply of the clock signal SCK, the 2 bits of printing data [SIH, SIL] corresponding to the ejector section 600 of that shift register 212 are held in the n shift registers 212. It should be noted that... Figure 4 In order to distinguish the n vertically connected shift registers 212, they are labeled as level 1, level 2, ..., level n from the upstream side to the downstream side of the input printed data signal SI.

[0071] Each of the n latching circuits 214 latches the 2 bits of printed data [SIH, SIL] held by the corresponding shift register 212 simultaneously during the rise of the latch signal LAT.

[0072] Each of the n decoders 216 will decode the 2-bit printed data [SIH, SIL] latched by the corresponding latch circuit 214, and output selection signals S1, S2, S3 corresponding to the logic level of the decoded content in each cycle T. Figure 5 This is a diagram illustrating an example of the decoded content in decoder 216. Decoder 216 outputs latched 2-bit printed data [SIH, SIL] and Figure 5 The selected signals S1, S2, and S3 specify the logic levels for the decoded content. For example, in the first embodiment, when the 2-bit printed data [SIH, SIL] latched by the corresponding latch circuit 214 is [1, 0], the decoder 216 sets the logic levels of the selected signals S1, S2, and S3 to L, H, and L levels respectively during the period T.

[0073] The selection circuit 230 is provided for each of the n ejector sections 600. That is, the drive signal selection circuit 200 has n selection circuits 230. The selection signals S1, S2, S3 and the drive signals COMA, COMB, COMC, output by the decoder 216 corresponding to the same ejector section 600 are input to the selection circuit 230. Then, the selection circuit 230 sets each of the drive signals COMA, COMB, COMC to selected or unselected based on the selection signals S1, S2, S3 and the drive signals COMA, COMB, COMC, thereby generating a drive signal VOUT and outputting it to the corresponding ejector section 600.

[0074] Figure 6 This is a diagram showing an example of the configuration of a selection circuit 230 corresponding to the amount of one ejector 600. (See diagram for example.) Figure 6 As shown, the selection circuit 230 has inverters 232a, 232b, 232c and switching gates 234a, 234b, 234c.

[0075] The selection signal S1 is input to the positive control terminal of the converter gate 234a (without a circular mark), while it is logically inverted by the inverter 232a and input to the negative control terminal of the converter gate 234a (with a circular mark). Additionally, a drive signal COMA is supplied to the input terminal of the converter gate 234a. When the input selection signal S1 is at a high level (H), the converter gate 234a connects the input and output terminals; when the input selection signal S1 is at a low level (L), it disconnects the input and output terminals. That is, the converter gate 234a outputs the drive signal COMA when the selection signal S1 is at a high level (H), and does not output the drive signal COMA when the selection signal S1 is at a low level (L).

[0076] The selection signal S2 is input to the positive control terminal of the converter gate 234b (without a circular mark), while it is logically inverted by the inverter 232b and input to the negative control terminal of the converter gate 234b (with a circular mark). Additionally, a drive signal COMB is supplied to the input terminal of the converter gate 234b. When the input selection signal S2 is at a high level (H), the converter gate 234b sets the input and output terminals to conduct; when the input selection signal S2 is at a low level (L), it sets the input and output terminals to non-conductivity. That is, the converter gate 234b outputs the drive signal COMB to the output terminal when the selection signal S2 is at a high level (H), and does not output the drive signal COMB to the output terminal when the selection signal S2 is at a low level (L).

[0077] The selection signal S3 is input to the positive control terminal of the converter gate 234c (without a circular mark), while it is logically inverted by the inverter 232c and input to the negative control terminal of the converter gate 234c (with a circular mark). Additionally, a drive signal COMC is supplied to the input terminal of the converter gate 234c. When the input selection signal S3 is at a high level (H), the converter gate 234c sets the input and output terminals to conduct; when the input selection signal S3 is at a low level (L), it sets the input and output terminals to non-conductivity. That is, the converter gate 234c outputs the drive signal COMC to the output terminal when the selection signal S3 is at a high level (H), and does not output the drive signal COMC to the output terminal when the selection signal S3 is at a low level (L).

[0078] The output terminals of switching gates 234a, 234b, and 234c are connected to a common ground. That is, drive signals COMA, COMB, and COMC, set by selection signals S1, S2, and S3 to indicate selection or non-selection, are supplied to the output terminals of the shared-ground-connected switching gates 234a, 234b, and 234c. The selection circuit 230 outputs the signal supplied to the shared-ground-connected output terminal as a drive signal VOUT to the corresponding ejector section 600.

[0079] The operation of the drive signal selection circuit 200 is explained. Figure 7 This diagram illustrates the operation of the drive signal selection circuit 200. The printing data signal SI is input serially, synchronously with the clock signal SCK, and sequentially transmitted by the shift register 212 corresponding to each ejector 600. Then, the input of the clock signal SCK stops, thereby storing the 2-bit printing data [SIH, SIL] corresponding to each ejector 600 in the corresponding shift register 212.

[0080] Subsequently, when the latch signal LAT rises, the two bits of printed data [SIH, SIL] held in shift register 212 are simultaneously latched by latch circuit 214. It should be noted that... Figure 7In the diagram, the 2-bit printed data [SIH, SIL] corresponding to the shift registers 212 of levels 1, 2, ..., n after being latched by the latching circuit 214 are illustrated as LT1, LT2, ..., LTn.

[0081] The decoder 216 outputs logic level selection signals S1, S2, and S3 based on the dot size specified by the latched 2-bit printed data [SIH, SIL].

[0082] Specifically, when the printed data [SIH, SIL] is [1, 1], the decoder 216 sets the logic levels of the selection signals S1, S2, and S3 to H, L, and L levels during period T and outputs them to the selection circuit 230. As a result, the selection circuit 230 selects the trapezoidal waveform Adp during period T and outputs the drive signal VOUT corresponding to the "large dot LD". Furthermore, when the printed data [SIH, SIL] is [1, 0], the decoder 216 sets the logic levels of the selection signals S1, S2, and S3 to L, H, and L levels during period T and outputs them to the selection circuit 230. As a result, the selection circuit 230 selects the trapezoidal waveform Bdp during period T and outputs the drive signal VOUT corresponding to the "small dot SD". Furthermore, when the printed data [SIH, SIL] is [0, 1], the decoder 216 sets the logic levels of the selection signals S1, S2, and S3 to L, L, and L levels during period T and outputs them to the selection circuit 230. As a result, selection circuit 230 does not select any one of the trapezoidal waveforms Adp, Bdp, and Cdp during period T, but outputs a constant drive signal VOUT corresponding to "No ejection ND" at voltage Vc. Furthermore, when the printed data [SIH, SIL] is [0, 0], decoder 216 sets the logic levels of selection signals S1, S2, and S3 to L, L, and H levels during period T and outputs them to selection circuit 230. As a result, selection circuit 230 selects trapezoidal waveform Cdp during period T and outputs the drive signal VOUT corresponding to "Micro-vibration BSD".

[0083] Here, when the selection circuit 230 does not select any one of the trapezoidal waveforms Adp, Bdp, and Cdp, the voltage Vc supplied by the piezoelectric element 60 is maintained immediately at one end of the corresponding piezoelectric element 60 by the capacitive component of the piezoelectric element 60. That is, the selection circuit 230 outputs a constant drive signal VOUT at voltage Vc, including the case where the voltage Vc just before it is maintained by the capacitive component of the piezoelectric element 60 when none of the trapezoidal waveforms Adp, Bdp, and Cdp are selected as drive signal VOUT, is supplied to the piezoelectric element 60 as drive signal VOUT.

[0084] As described above, the drive signal selection circuit 200 sets the drive signals COMA, COMB, and COMC to selected or unselected based on the print data signal SI, the latch signal LAT, and the clock signal SCK, thereby generating a drive signal VOUT corresponding to each of the plurality of ejector sections 600 and outputting it to the corresponding ejector section 600. Thus, the amount of ink ejected from each of the plurality of ejector sections 600 is individually controlled.

[0085] 3. Composition of the liquid ejection module

[0086] Next, use Figures 8-10 Explain the structure of the liquid ejection module 20. Figure 8 This is a diagram showing the structure of the liquid ejection module 20. Here, when describing the structure of the liquid ejection module 20, Figures 8-10 The diagram shows arrows representing the mutually orthogonal X1, Y1, and Z1 directions. Additionally, in... Figures 8-10 In the description, the starting side of the arrow showing the X1 direction is sometimes referred to as the -X1 side, and the front end side as the +X1 side; the starting side of the arrow showing the Y1 direction is referred to as the -Y1 side, and the front end side as the +Y1 side; the starting side of the arrow showing the Z1 direction is referred to as the -Z1 side, and the front end side as the +Z1 side. Furthermore, in the following description, the liquid ejection module 20 provided in the liquid ejection device 1 of the first embodiment is described as having six ejection modules 23. When distinguishing each of the six ejection modules 23, they are sometimes referred to as ejection modules 23-1 to 23-6.

[0087] The liquid ejection module 20 includes a housing 31, a collection substrate 33, a flow path structure 34, a head substrate 35, a distribution flow path 37, a fixing plate 39, and ejection modules 23-1 to 23-6. Furthermore, in the liquid ejection module 20, the flow path structure 34, the head substrate 35, the distribution flow path 37, and the fixing plate 39 are stacked along the Z1 direction from the -Z1 side to the +Z1 side in the order of fixing plate 39, distribution flow path 37, head substrate 35, and flow path structure 34. The housing 31 is located around the flow path structure 34, head substrate 35, distribution flow path 37, and fixing plate 39 to support them. Furthermore, the assembly substrate 33 is erected on the +Z1 side of the housing 31 in a state held by the housing 31, and the six ejection modules 23 are arranged between the distribution flow path 37 and the fixing plate 39 in such a way that a portion of them are exposed to the outside of the liquid ejection module 20.

[0088] When describing the structure of the liquid ejection module 20, the structure of the ejection module 23 included in the liquid ejection module 20 will be described first. Figure 9This is a diagram showing an example of the structure of the ejection module 23. Additionally, Figure 10 This is a diagram showing an example of a cross-section of the ejection module 23. Here, Figure 10 It is Figure 9 The Aa line shown is cut Figure 9 The cross-sectional view shown is of the ejection module 23. Additionally, Figure 10 The line Aa shown is a virtual line segment that passes through the guide path 661 of the ejection module 23 and through nozzles N1 and N2.

[0089] like Figure 9 and Figure 10 As shown, the ejection module 23 has a plurality of nozzles N1 and a plurality of nozzles N2 arranged side by side. The total number of nozzles N1 and N2 in the ejection module 23 is n, the same number as the ejection section 600 in the ejection module 23. It should be noted that in the first embodiment, the number of nozzles N1 and nozzles N2 in the ejection module 23 is described as the same. That is, it is described as the ejection module 23 having n / 2 nozzles N1 and n / 2 nozzles N2. Here, in the following description, when it is not necessary to distinguish between nozzles N1 and nozzles N2, they are sometimes simply referred to as nozzle N.

[0090] The ejection module 23 has a wiring component 388, a housing 660, a protective substrate 641, a flow path forming substrate 642, a connecting plate 630, a flexible substrate 620, and a nozzle plate 623.

[0091] In the flow path forming substrate 642, pressure chamber CB1, which is divided by multiple partition walls through anisotropic etching from one side, is arranged side-by-side with nozzle N1, and pressure chamber CB2, which is divided by multiple partition walls through anisotropic etching from one side, is arranged side-by-side with nozzle N2. Here, in the following description, when it is not necessary to distinguish between pressure chamber CB1 and pressure chamber CB2, they are sometimes simply referred to as pressure chamber CB.

[0092] The nozzle plate 623 is located on the -Z1 side of the flow path forming substrate 642. The nozzle plate 623 is provided with a nozzle array Ln1 formed by n / 2 nozzles N1 and a nozzle array Ln2 formed by n / 2 nozzles N2. Here, in the following description, the surface of the nozzle plate 623 on the -Z1 side where the nozzles N are open is sometimes referred to as the liquid jetting surface 623a.

[0093] A connecting plate 630 is disposed on the -Z1 side of the flow path forming substrate 642 and on the +Z1 side of the nozzle plate 623. A nozzle connecting path RR1 connecting pressure chamber CB1 and nozzle N1, and a nozzle connecting path RR2 connecting pressure chamber CB2 and nozzle N2 are provided on the connecting plate 630. Furthermore, a pressure chamber connecting path RK1 connecting the end of pressure chamber CB1 to manifold MN1, and a pressure chamber connecting path RK2 connecting the end of pressure chamber CB2 to manifold MN2 are independently provided on the connecting plate 630 corresponding to each of the pressure chambers CB1 and CB2.

[0094] Manifold MN1 includes a supply connection path RA1 and a connecting connection path RX1. The supply connection path RA1 extends through the connecting plate 630 along the Z1 direction, while the connecting connection path RX1 does not extend through the connecting plate 630 along the Z1 direction. Instead, it opens towards the nozzle plate 623 side of the connecting plate 630 and extends to the middle of the Z1 direction. Similarly, manifold MN2 includes a supply connection path RA2 and a connecting connection path RX2. The supply connection path RA2 extends through the connecting plate 630 along the Z1 direction, while the connecting connection path RX2 does not extend through the connecting plate 630 in the Z1 direction. Instead, it opens towards the nozzle plate 623 side of the connecting plate 630 and extends to the middle of the Z1 direction. Furthermore, the connecting connection path RX1 of manifold MN1 is connected to the corresponding pressure chamber CB1 via the pressure chamber connection path RK1, and the connecting connection path RX2 of manifold MN2 is connected to the corresponding pressure chamber CB2 via the pressure chamber connection path RK2.

[0095] In the following description, when it is not necessary to distinguish between nozzle connection RR1 and nozzle connection RR2, they are sometimes simply referred to as nozzle connection RR, and when it is not necessary to distinguish between manifold MN1 and manifold MN2, they are sometimes simply referred to as manifold MN. Similarly, when it is not necessary to distinguish between supply connection RA1 and supply connection RA2, they are sometimes simply referred to as supply connection RA, and when it is not necessary to distinguish between connecting connection RX1 and connecting connection RX2, they are sometimes simply referred to as connecting connection RX.

[0096] A vibrating plate 610 is disposed on the +Z1 side of the flow path forming substrate 642. Furthermore, piezoelectric elements 60 are formed in two rows on the +Z1 side of the vibrating plate 610, corresponding to nozzles N1 and N2. One electrode of each piezoelectric element 60 and a piezoelectric body layer are formed for each pressure chamber CB, and the other electrode of each piezoelectric element 60 is configured as a common electrode relative to the pressure chamber CB. A drive signal VOUT is supplied from the drive signal selection circuit 200 to one electrode of the piezoelectric element 60, and a reference voltage signal VBS is supplied to the common electrode, which is the other electrode of the piezoelectric element 60.

[0097] A protective substrate 641 is bonded to the +Z1 side of the flow path forming substrate 642. The protective substrate 641 forms a protective space 644 for protecting the piezoelectric element 60. Furthermore, a through hole 643 extending along the Z1 direction is provided in the protective substrate 641. The end of a lead electrode 611 leading from the electrode of the piezoelectric element 60 extends outwards from the inside of the through hole 643. A wiring member 388 is electrically connected to the end of the lead electrode 611 exposed inside the through hole 643.

[0098] Additionally, a housing 660 is fixed to the protective substrate 641 and the connecting plate 630. This housing 660 divides a portion of the manifold MN, which communicates with multiple pressure chambers CB. The housing 660 is engaged with the protective substrate 641 and also with the connecting plate 630. Specifically, the housing 660 has a recess 665 on the -Z1 side surface that accommodates the flow path forming substrate 642 and the protective substrate 641. The recess 665 has a wider opening area than the flow path forming substrate 642 to which the protective substrate 641 is engaged. Furthermore, when the recess 665 accommodates the flow path forming substrate 642, the opening surface on the -Z1 side of the recess 665 is sealed by the connecting plate 630. Thus, the housing 660, the flow path forming substrate 642, and the protective substrate 641 divide the outer periphery of the flow path forming substrate 642 into a supply connecting path RB1 and a supply connecting path RB2. Here, when it is not necessary to distinguish between the supply connecting path RB1 and the supply connecting path RB2, they are sometimes simply referred to as the supply connecting path RB.

[0099] Furthermore, a flexible substrate 620 is provided on the surface of the connecting plate 630 where the supply connecting path RA and the connection connecting path RX open. This flexible substrate 620 seals the openings of the supply connecting path RA and the connection connecting path RX. This flexible substrate 620 has a sealing film 621 and a fixing substrate 622. The sealing film 621 is formed of a flexible thin film or the like, and the fixing substrate 622 is formed of a rigid material such as stainless steel.

[0100] The housing 660 is provided with an inlet path 661 for supplying ink to the manifold MN. In addition, the housing 660 is provided with a connection port 662 in which the wiring member 388 is inserted, which communicates with the through hole 643 of the protective substrate 641 and extends along the Z1 direction.

[0101] The wiring component 388 is a flexible component for electrically connecting the ejection module 23 and the head substrate 35, and an FPC can be used for example. Additionally, an integrated circuit 201 is mounted on the wiring component 388 in a COF (Chip On Film) configuration. At least a portion of the aforementioned drive signal selection circuit 200 is mounted on this integrated circuit 201.

[0102] In the ejection module 23 configured as described above, the drive signal VOUT and the reference voltage signal VBS output by the drive signal selection circuit 200 are supplied to the piezoelectric element 60 via the wiring member 388. The piezoelectric element 60 is then driven by the change in the potential difference between the drive signal VOUT and the reference voltage signal VBS. As the piezoelectric element 60 is driven, the vibrating plate 610 displaces in the vertical direction, causing a change in the internal pressure of the pressure chamber CB. Furthermore, due to the change in the internal pressure of the pressure chamber CB, the ink stored inside the pressure chamber CB is ejected from the corresponding nozzle N. Here, the ejection module 23, including the nozzle N, the nozzle connection path RR, the pressure chamber CB, the piezoelectric element 60, and the vibrating plate 610, corresponds to the aforementioned ejection section 600.

[0103] Return to Figure 8 The fixing plate 39 is located on the -Z1 side of the ejection module 23. The fixing plate 39 fixes six ejection modules 23. Specifically, the fixing plate 39 has six openings 391 that extend through the fixing plate 39 along the Z1 direction. The liquid injection surface 623a of the ejection module 23 is exposed from each of these six openings 391. That is, six ejection modules 23 are fixed to the fixing plate 39 in such a way that the liquid injection surface 623a is exposed from each of the corresponding openings 391.

[0104] The distribution flow path 37 is located on the +Z1 side of the ejection module 23. Four inlet portions 373 are provided on the +Z1 side surface of the distribution flow path 37. These four inlet portions 373 are flow pipes protruding from the +Z1 side surface of the distribution flow path 37 along the Z1 direction towards the +Z1 side, communicating with flow holes (not shown) formed on the -Z1 side surface of the flow path structure 34. Additionally, a flow pipe (not shown) communicating with the four inlet portions 373 is located on the -Z1 side surface of the distribution flow path 37. This flow pipe (not shown) on the -Z1 side surface of the distribution flow path 37 communicates with the inlet paths 661 of each of the six ejection modules 23. Furthermore, the distribution flow path 37 has six openings 371 extending along the Z1 direction. Wiring members 388 of each of the six ejection modules 23 are inserted into these six openings 371.

[0105] The head substrate 35 is located on the +Z1 side of the distribution flow path 37. A wiring component FC, electrically connected to the assembly substrate 33 (described later), is mounted on the head substrate 35. Furthermore, four openings 351 and cutouts 352 and 353 are formed on the head substrate 35. Wiring components 388 of the ejection modules 23-2 to 23-5 are inserted through the four openings 351. The wiring components 388 of each of the ejection modules 23-2 to 23-5, which are inserted through the four openings 351, are electrically connected to the head substrate 35 by soldering or the like. The wiring component 388 of the ejection module 23-1 passes through the cutout 352, and the wiring component 388 of the ejection module 23-6 passes through the cutout 353. The wiring components 388 of each of the ejection modules 23-1 and 23-6, which pass through each of the cutouts 352 and 353, are electrically connected to the head substrate 35 by soldering or the like.

[0106] In addition, four cutouts 355 are formed at the four corners of the head substrate 35. The inlet portion 373 passes through the four cutouts 355. Furthermore, the four inlet portions 373 passing through the cutouts 355 are connected to the flow path structure 34 located on the +Z1 side of the head substrate 35.

[0107] The flow path structure 34 has a flow path plate Su1 and a flow path plate Su2. The flow path plate Su1 and the flow path plate Su2 are stacked along the Z1 direction with the flow path plate Su1 on the +Z1 side and the flow path plate Su2 on the -Z1 side, and are joined together by an adhesive or the like.

[0108] The flow path structure 34 has four inlet portions 341 protruding towards the +Z1 side along the Z1 direction on its +Z1 side surface. These four inlet portions 341 communicate with flow path holes (not shown) formed on the -Z1 side surface of the flow path structure 34 via ink flow paths formed inside the flow path structure 34. Furthermore, the flow path holes (not shown) formed on the -Z1 side surface of the flow path structure 34 communicate with the four inlet portions 373. Additionally, a through hole 343 extending along the Z1 direction is formed in the flow path structure 34. A wiring member FC electrically connected to the head substrate 35 is inserted into the through hole 343. Furthermore, inside the flow path structure 34, in addition to the ink flow path connecting the inlet portions 341 to the flow path holes (not shown) formed on the -Z1 side surface, a filter or similar device may be provided to replenish foreign matter contained in the ink flowing through the ink flow path.

[0109] The housing 31 is arranged to cover the flow path structure 34, the head base plate 35, the distribution flow path 37, and the fixing plate 39, and supports the flow path structure 34, the head base plate 35, the distribution flow path 37, and the fixing plate 39. The housing 31 has four openings 311, a collection base plate insertion part 313, and a holding member 315.

[0110] Each of the four openings 311 has four inlet sections 341 of the flow path structure 34 inserted through it. Ink is supplied from the liquid container 3 to the four inlet sections 341 through which the four openings 311 are inserted via tubes (not shown).

[0111] The retaining member 315 holds the assembly substrate 33 in a state where a portion of the assembly substrate 33 is inserted through the assembly substrate insertion portion 313. A connecting portion 330 is provided on the assembly substrate 33. Various signals, such as data signals DATA, drive signals COMA, COMB, COMC, reference voltage signal VBS, and other power supply voltages, output from the head drive module 10 are input to the connecting portion 330 via the wiring member 30. Furthermore, the assembly substrate 33 is electrically connected to the wiring member FC of the head substrate 35. Thus, the assembly substrate 33 and the head substrate 35 are electrically connected. A semiconductor device including the aforementioned recovery circuit 220 may also be provided on this assembly substrate 33. It should be noted that... Figure 8 The illustration shows a case where the assembly substrate 33 has one connection portion 330, but it is not limited to this configuration. For example, when the head unit 5 has multiple wiring members 30, and various signals such as data signals DATA, drive signals COMA, COMB, COMC, reference voltage signal VBS, and other power supply voltages output by the head drive module 10 are input to the assembly substrate 33 via the multiple wiring members 30, the assembly substrate 33 may have multiple connection portions 330 corresponding to each of the multiple wiring members 30.

[0112] In the liquid ejection module 20 configured as described above, the liquid container 3 and the inlet 341 are connected via a pipe (not shown), thereby supplying ink stored in the liquid container 3. The ink supplied to the liquid ejection module 20 is then guided through an ink flow path formed inside the flow path structure 34 to a flow path hole (not shown) formed on the -Z1 side of the flow path structure 34, and then supplied to the four inlet 373s of the distribution flow path 37. The ink supplied to the distribution flow path 37 via the four inlet 373 is distributed in the ink flow path (not shown) formed inside the distribution flow path 37 to every six ejection modules 23, and then supplied to the inlet path 661 of the corresponding ejection module 23. The ink supplied to the ejection module 23 via the inlet path 661 is then stored in the pressure chamber CB included in the ejection section 600.

[0113] Furthermore, the head drive module 10 and the liquid ejection module 20 are electrically connected by one or more wiring members 30. Thus, various signals, including the drive signals COMA, COMB, COMC, reference voltage signal VBS, and data signal DATA output from the head drive module 10, are supplied to the liquid ejection module 20. These various signals, including the drive signals COMA, COMB, COMC, reference voltage signal VBS, and data signal DATA input to the liquid ejection module 20, propagate in the assembly substrate 33 and the head substrate 35. At this time, the recovery circuit 220 generates clock signals SCK1 to SCK6, printed data signals SI1 to SI6, and latch signals LAT1 to LAT6 corresponding to each of the ejection modules 23-1 to 23-6 from the data signal DATA. Then, through the integrated circuit 201, which includes a drive signal selection circuit 200 provided in the wiring member 388, a drive signal VOUT corresponding to each of the n ejection sections 600 is generated and supplied to the piezoelectric element 60 contained in the corresponding ejection section 600. As a result, the piezoelectric element 60 is driven, and the ink stored in the pressure chamber CB is ejected.

[0114] 4. Structure of the head driver module

[0115] Next, refer to Figures 11-13 The structure of the head drive module 10 will be described. In the following description, arrows showing mutually orthogonal X2, Y2, and Z2 directions are illustrated in directions independent of the aforementioned X1, Y1, and Z1 directions. Additionally, the starting side of the arrow showing the X2 direction is sometimes referred to as the -X2 side, and the leading side as the +X2 side; the starting side of the arrow showing the Y2 direction is referred to as the -Y2 side, and the leading side as the +Y2 side; the starting side of the arrow showing the Z2 direction is referred to as the -Z2 side, and the leading side as the +Z2 side. Furthermore, as an example, the case where the Z2 direction is the direction opposite to the direction of gravity, i.e., upward, will be described. Furthermore, as an example, the case where the direction opposite to the X2 direction is the transport direction will be described. Furthermore, as an example, the case where the direction parallel to the Y2 direction is the main scanning direction will be described. Furthermore, as an example, the case where m = 6 will be described below. It should be noted that, in this embodiment, as an example, the case where the control circuit 100 and the conversion circuit 120 are included in a shared FPGA will be described. However, the conversion circuit 120 can also be configured not to be included in the FPGA.

[0116] Figure 11 This is a perspective view showing an example of the structure of the head drive module 10. (See diagram below.) Figure 11As shown, the head drive module 10 includes: a first circuit board B1, a second circuit board B2, a control circuit 100, a conversion circuit 120, six drive circuit sections DRV1 to DRV6, a first connector CN1, a second connector CN2, a third connector CN3, and a fourth connector CN4. It should be noted that when it is not necessary to distinguish between the six drive circuit sections DRV1 to DRV6, they are sometimes simply referred to as drive circuit sections DRV.

[0117] The first circuit board B1 is a power supply board that supplies power to the various components included in the head drive module 10. Furthermore, the first circuit board B1 is disposed on a surface that is more compact than the liquid ejection module 20 when the head drive module 10 is connected to it. Figure 11 The liquid ejection module 20 (not shown) is a substrate on the +Z2 side. Additionally, the first circuit board B1 is a flat substrate with two surfaces, namely the first surface M1 and the second surface M2, each having a long side extending in the Z2 direction and a short side extending in the Y2 direction.

[0118] In this embodiment, the extension of a component in a certain direction, either along its long or short side, can mean either the component extending in that direction or extending in a direction oblique to that direction. As an example, see below... Figure 11 As shown, the first circuit board B1 is a flat substrate in which the long side of the first surface M1 and the second surface M2 extends in the Z2 direction and the width of the first surface M1 and the second surface M2 extends in the Y2 direction.

[0119] It should be noted that the first circuit board B1 is configured to be connected to the liquid ejection module 20 via wiring member 30, but it can also be configured as a set of boards 33 connected to the liquid ejection module 20 via board-to-board (BtoB) connection without wiring member 30. Here, BtoB connection refers to electrically connecting two boards via a pair of connectors mounted on the boards without using wires or flexible wiring boards. In the case of BtoB connection without wiring member 30, the wiring path of the drive signals COMA, COMB, and COMC generated by the head drive module 10 until they are input to the selection circuit 230 is shortened, and the influence of the inductance of the drive signals COMA, COMB, and COMC from the wiring path is reduced. Therefore, the accuracy of the drive signal VOUT output from the selection circuit 230 and applied to the piezoelectric element 60 is improved, and the ejection stability of the liquid ejection module 20 is improved.

[0120] Six drive circuit units (DRVs) and a second circuit board B2 are mounted on the first surface M1 of the first circuit board B1. Furthermore, a first connector CN1 is provided at the -Z2 side of one end of the first surface M1 of the first circuit board B1. Additionally, each of the second connector CN2 and the third connector CN3 is provided at the +Z2 side of one end of the second surface M2 of the first circuit board B1. Thus, the first circuit board B1 has the first connector CN1, the second connector CN2, and the third connector CN3.

[0121] The first connector CN1 is a connector that connects the transmission cables carrying the drive signals COMA, COMB, and COMC output from each of the drive circuits 52a, 52b, and 52c. The first connector CN1 is connected to the liquid ejection module 20 or to a wiring component 30 connected to the liquid ejection module 20. Therefore, the drive signals COMA, COMB, and COMC output from the drive circuits 52a, 52b, and 52c are output to the liquid ejection module 20 via the first connector CN1. Figure 11 In the example shown, the first connector CN1 is disposed on the first surface M1 and the second surface M2 of the two surfaces of the first circuit board B1.

[0122] The second connector CN2 and the third connector CN3 are connectors that connect to the power cable supplying power to the first circuit board B1, which serves as a power supply board. The second connector CN2 and the third connector CN3 are disposed on the second surface M2 of the first circuit board B1. It should be noted that the second connector CN2 and the third connector CN3 may also be disposed on the first surface M1 of the first circuit board B1.

[0123] The i-th drive circuit unit DRVi of the six drive circuit units DRV is disposed on the first surface M1 of the first circuit board B1. In other words, the drive circuit unit DRVi is connected to the first surface M1 of the first circuit board B1. The drive circuit unit DRVi includes a drive signal output circuit 50-i. That is, the drive circuit unit DRVi includes Figure 11 It consists of three driving circuits (not shown) 52a, 52b, and 52c, and a reference voltage output circuit 53. Here, i is any integer from 1 to 6.

[0124] Additionally, the drive circuit section DRVi includes a third circuit board B3 on which the drive signal output circuit 50-i is mounted, and a heat sink HS2.

[0125] Here, as Figure 11As shown, the third circuit board B3 is connected to the first circuit board B1 via a B-to-B connection and stands upright relative to the first circuit board B1. Therefore, all connections of the third circuit board B3 to other boards are via B-to-B connections to the first circuit board B1. Additionally, as... Figure 12 As shown, the third circuit board B3 is a flat board with a drive signal output circuit 50-i mounted on it. Figure 12 This diagram shows a mounting example of the drive signal output circuit 50-1 on the third circuit board B3 included in the drive circuit section DRV1. It should be noted that the mounting examples of the drive signal output circuits 50-2 to 50-6 on the third circuit board B3 are the same as the mounting example of the drive signal output circuit 50-1 on the third circuit board B3, and therefore descriptions are omitted. Figure 12 In the example shown, on the third circuit board B3 of the drive circuit section DRV1, three integrated circuits (ICs), three field-effect transistors (FETs), three coils (RCs), and one electrolytic capacitor (CP) are mounted as D-stage amplifier circuits, constituting each of the drive circuits 52a, 52b, and 52c. Furthermore, in this example, on the third circuit board B3, the three ICs, three FETs, and three RCs are arranged in the X2 direction in the order of three RCs, three FETs, and three ICs. Additionally, in this example, the three ICs are arranged facing the Z2 direction. Also, in this example, the three FETs are arranged facing the Z2 direction. Furthermore, in this example, the RCs are arranged facing the Z2 direction. Finally, in this example, the electrolytic capacitor (CP) is located on the -X2 side closer to the three RCs. That is, in this example, the third circuit board B3 has an electrolytic capacitor CP mounted on the side of the drive circuits 52a, 52b, and 52c of the drive signal output circuit 50-1 closest to the first circuit board B1. It should be noted that the third circuit board B3 may also be configured to mount other types of capacitors instead of the electrolytic capacitor CP.

[0126] Furthermore, a fifth connector CN5 is provided at the -X2 side end of the third circuit board B3 of the drive circuit section DRV1. The fifth connector CN5 connects to a connector (not shown) provided on the first circuit board B1. Thus, the drive circuit section DRV1 and the first circuit board B1 are connected via a BtoB connection. Consequently, the drive circuit section DRV1 is connected to the first circuit board B1 in a direction that intersects with the first circuit board B1. Figure 11In the example shown, the drive circuit section DRV1 is connected to the first circuit board B1 via a BtoB connection, extending in a direction orthogonal to the first circuit board B1, i.e., the X2 direction. Additionally, the fifth connector CN5 is used to output the drive signals COMA, COMB, and COMC from each of the drive circuits 52a, 52b, and 52c included in the drive circuit section DRV1 to the liquid ejection module 20 via the first circuit board B1.

[0127] The heat sink HS2 is used to cool the drive signal output circuit 50-i. The heat sink HS2 is disposed on the third circuit board B3 in such a way that the drive signal output circuit 50-i mounted on the third circuit board B3 is clamped together with the third circuit board B3. Figure 13 This is a diagram illustrating an example of the positional relationship between the heat sink HS2, the drive signal output circuit 50-i, and the third circuit board B3. Here, in Figure 11 , Figure 13 In the example shown, the drive circuit section DRVi has a roughly rectangular shape. This shape is formed by the third circuit board B3 and the heat sink HS2 included in the drive circuit section DRVi. The heat sink HS2, provided in the drive signal output circuit 50-i, is composed of a first flat plate member HS21, a second flat plate member HS22, a first connecting member HS23 connecting the first flat plate member HS21 and the second flat plate member HS22, and multiple fins Fn provided on the first flat plate member HS21. The first flat plate member HS21 is a flat plate-shaped member that contacts each of the three integrated circuits IC and the three field-effect transistors FET on the third circuit board B3. Figure 13 In the diagram, to simplify the representation, the three integrated circuits (ICs) on the third circuit board B3 are shown as a single cuboid-shaped object. Additionally, in... Figure 13In the diagram, for simplification, the three field-effect transistors (FETs) on the third circuit board B3 are shown as a single cuboid. The second plate member HS22 is a plate-shaped member parallel to the first plate member HS21, and is located further away from the third circuit board B3 than the first plate member HS21. Furthermore, when viewing the heat sink HS2 in the Y2 direction, the +X2 side end of the second plate member HS22 overlaps with the -X2 side end of the first plate member HS21. The first connecting member HS23 is a plate-shaped member connecting these two ends, and is parallel to the Y2-Z2 plane. Here, the three coils RC, electrolytic capacitors CP, etc., mounted on the third circuit board B3 are located in the space between the second plate member HS22 and the third circuit board B3. Each of the plurality of fins Fn is a plate-shaped fin parallel to the Y2-Z2 plane. Because the heat sink HS2 is configured in this way, these plurality of fins Fn hardly obstruct the airflow along the Z2 direction. In addition, such as Figure 13 As shown, since the heat sink HS2 is constructed without any flat plate-shaped components parallel to the X2-Y2 plane, the airflow along the Z2 direction is hardly obstructed by the heat sink HS2. As a result, the airflow along the Z2 direction can efficiently dissipate heat from the drive circuit section DRVi.

[0128] like Figure 11 As shown, the second circuit board B2 is a flat substrate and serves as an interface board on which the control circuit 100 and the conversion circuit 120 are mounted. More specifically, the second circuit board B2 is mounted on the first surface M1 of the first circuit board B1 at a position closer to +Z2 than the six drive circuit sections DRV. Furthermore, in Figure 11 In the example shown, the second circuit board B2 is connected to the first circuit board B1 via a BtoB connection. It should be noted that the second circuit board B2 may also be connected to the first circuit board B1 via a connection different from the BtoB connection. Furthermore, a fourth connector CN4 is provided at the +Z2 side end of the second circuit board B2. Therefore, in this example, in the head drive module 10, the first connector CN1, the six drive circuit units DRV, the conversion circuit 120, and the fourth connector CN4 are arranged in the Z2 direction in the following order: first connector CN1, six drive circuit units DRV, conversion circuit 120, and fourth connector CN4.

[0129] The fourth connector CN4 is a connector that connects the transmission cable for transmitting signals such as image information signals IP input to the control circuit 100. Therefore, image information signals IP are input to the control circuit 100 via the fourth connector CN4. Additionally, the fourth connector CN4 is also a connector for transmitting control signals input to the conversion circuit 120. Therefore, control signals are input to the conversion circuit 120 via the fourth connector CN4. Here, as described above, the second circuit board B2 is connected to the first circuit board B1 via a B-to-B connection. Therefore, the conversion circuit 120 operates using power supplied from the first circuit board B1 to the second circuit board B2. On the other hand, control signals are input to the second circuit board B2 via the fourth connector CN4, without passing through the first circuit board B1. That is, the conversion circuit 120 receives control signals via the fourth connector CN4, without passing through the first circuit board B1. It should be noted that the fourth connector CN4 is, for example, an optical angle connector, but it can be replaced by other types of connectors.

[0130] 5. Structure of the cooling unit

[0131] Next, the structure of the cooling unit 6, which cools the head drive module 10, will be described. It should be noted that, for simplicity, the liquid ejection device 1 will hereby be assumed to have three head units 5 that eject ink of the same color. That is, the liquid ejection device 1 has three head drive modules 10. In this case, these three head units 5 constitute a line head. However, the number of head units 5, i.e., the number of head drive modules 10, is not limited to three.

[0132] Figure 14 This diagram illustrates an example of the structure of the cooling unit 6, and is a front view of the cooling unit 6 viewed from the -X2 side. (See diagram for reference.) Figure 14 As shown, the cooling unit 6 has a channel 700, an intake fan FNi, an exhaust fan FNo, three intake-side adjustment sections RVi1, RVi2, and RVi3, and three exhaust-side adjustment sections RVO1, RVO2, and RVO3.

[0133] The channel 700 includes a common intake air tunnel WTi, a common exhaust air tunnel WTo, a first air tunnel WT1, a second air tunnel WT2, and a third air tunnel WT3, serving as a path for cooling air. In other words, the common intake air tunnel WTi, the common exhaust air tunnel WTo, the first air tunnel WT1, the second air tunnel WT2, and the third air tunnel WT3 constitute the channel 700, restricting the direction of air movement within it to a predetermined direction. The first air tunnel WT1, the second air tunnel WT2, and the third air tunnel WT3 are arranged between the common intake air tunnel WTi and the common exhaust air tunnel WTo, respectively connecting the common intake air tunnel WTi and the common exhaust air tunnel WTo.

[0134] The shared intake air duct WTi is a cylindrical air duct extending along the Y2 direction. The shared intake air duct WTi is equivalent to the intake port of channel 700, drawing in air from outside the outer casing HS through the opening on the +Y2 side. The opening on the -Y2 side of the shared intake air duct WTi connects to the openings of the first air duct WT1, the second air duct WT2, and the third air duct WT3. It should be noted that the shared intake air duct WTi can also protrude outwards from the outer casing HS (see reference). Figure 15 ).

[0135] The first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3 are U-shaped cylindrical wind tunnels. Specifically, the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3 extend along the Z2 direction in the central part of the path, and the ends on the -Z2 side and the +Z2 side bend towards the +Y2 side in the Y2 direction. The opening on the -Y2 side of the aforementioned common intake wind tunnel WT1 is connected to the opening on the -Z2 side of the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3.

[0136] Wind tunnels WT1, WT2, and WT3 are arranged along the Y2 direction in the central part of the path. Specifically, wind tunnels WT1, WT2, and WT3 are arranged from the +Y2 side to the -Y2 side in the following order: WT1, WT2, and WT3. In other words, wind tunnel WT2 is adjacent to the outer periphery of the U-shaped wind tunnel WT1, and wind tunnel WT3 is adjacent to the outer periphery of the U-shaped wind tunnel WT2. Wind tunnels WT1 and WT2 can be separated by plate-like components or arranged with space between them. Similarly, wind tunnels WT2 and WT3 can be separated by plate-like components or arranged with space between them.

[0137] The common exhaust duct WT1 is a cylindrical duct extending along the Y2 direction. The opening on the -Y2 side of the common exhaust duct WT1 connects to the openings on the +Z2 side of the first duct WT1, the second duct WT2, and the third duct WT3. The common exhaust duct WT1 is equivalent to the exhaust port of channel 700, discharging air from the opening on the +Y2 side to the outside of the outer casing HS. It should be noted that the common exhaust duct WT1 can also protrude to the outside of the outer casing HS (see reference). Figure 15 ).

[0138] An intake fan FNi is disposed within a common intake duct WTi, drawing in air from outside the housing HS through an opening on the +Y2 side of the common intake duct WTi and directing it into the channel 700. Conversely, an exhaust fan FNo is disposed within a common exhaust duct WTo, expelling air from the channel 700 through an opening on the +Y2 side of the common exhaust duct WTo to the outside of the housing HS. In other words, the rotation of the intake fan FNi and the exhaust fan FNo generates airflow within the channel 700. Air drawn into the common intake duct WTi from outside the housing HS is distributed through paths via the first duct WT1, the second duct WT2, and the third duct WT3. Then, the air that has passed through the first duct WT1, the second duct WT2, and the third duct WT3 merges within the common exhaust duct WTo and is exhausted to the outside of the housing HS. It should be noted that the channel 700 is preferably configured such that, apart from the opening on the +Y2 side of the common intake duct WTi (which serves as an intake port) and the opening on the +Y2 side of the common exhaust duct WTo (which serves as an exhaust port), there is no air inflow or outflow. With this configuration, the direction of air movement within the channel 700 can be restricted to a predetermined direction, thus preventing air from flowing into the channel 700 from the housing HS. Therefore, even if a portion of the ink ejected from the ejector 600 floats as a mist within the housing HS, the risk of ink mist entering the channel 700 can be reduced.

[0139] Intake-side adjustment unit RVi1 is located near the opening on the -Z2 side of the first wind tunnel WT1, intake-side adjustment unit RVi2 is located near the opening on the -Z2 side of the second wind tunnel WT2, and intake-side adjustment unit RVi3 is located near the opening on the -Z2 side of the third wind tunnel WT3. Intake-side adjustment units RVi1, RVi2, and RVi3 are adjustment valves that can adjust the opening area of ​​the openings on the -Z2 side of the first wind tunnel WT1, second wind tunnel WT2, and third wind tunnel WT3, respectively. Therefore, the amount of air drawn into the first wind tunnel WT1, second wind tunnel WT2, and third wind tunnel WT3 from the common intake wind tunnel WTi can be adjusted using intake-side adjustment units RVi1, RVi2, and RVi3. In other words, the air drawn into the common intake wind tunnel WTi is distributed to the first wind tunnel WT1, second wind tunnel WT2, and third wind tunnel WT3 according to the adjustment state of the intake-side adjustment units RVi1, RVi2, and RVi3.

[0140] Exhaust-side adjustment unit RVO1 is located near the opening on the +Z2 side of the first wind tunnel WT1, exhaust-side adjustment unit RVO2 is located near the opening on the +Z2 side of the second wind tunnel WT2, and exhaust-side adjustment unit RVO3 is located near the opening on the +Z2 side of the third wind tunnel WT3. Exhaust-side adjustment units RVO1, RVO2, and RVO3 are adjustment valves that can adjust the opening area of ​​the openings on the +Z2 side of the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3, respectively. Therefore, by means of exhaust-side adjustment units RVO1, RVO2, and RVO3, the amount of air discharged from the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3 to the common exhaust wind tunnel WTTo can be adjusted. In other words, the amount of air discharged from the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3 to the common exhaust wind tunnel WTTo corresponds to the adjustment state of exhaust-side adjustment units RVO1, RVO2, and RVO3.

[0141] Three head drive modules 10 are respectively disposed inside the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3. Specifically, the three head drive modules 10 are disposed along the Z2 direction at the center of the paths in the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3. In the following description, the head drive module 10 disposed in the first wind tunnel WT1 is sometimes referred to as head drive module 10-1, the head drive module 10 disposed in the second wind tunnel WT2 is referred to as head drive module 10-2, and the head drive module 10 disposed in the third wind tunnel WT3 is referred to as head drive module 10-3. That is, head drive module 10-1 is cooled by the airflow passing through the first wind tunnel WT1, head drive module 10-2 is cooled by the airflow passing through the second wind tunnel WT2, and head drive module 10-3 is cooled by the airflow passing through the third wind tunnel WT3.

[0142] It should be noted that the head drive module 10 can also be configured to be partially exposed from the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3. Additionally, a portion of the head drive module 10, such as the first circuit board B1, can also be part of the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3. However, in the head drive module 10, parts that require special cooling, such as the drive circuit section DRV, and parts at risk of short circuits due to ink mist adhesion, are also located inside the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3.

[0143] The cooling unit 6 configured in this way generates airflow within the channel 700 and cools the head drive module 10 by driving either the intake fan FNi or the exhaust fan FNo, or both. When driving both the intake fan FNi and the exhaust fan FNo, it is preferable that the airflow rate of the intake fan FNi is greater than that of the exhaust fan FNo. This allows a positive pressure to be established within the channel 700, thereby further reducing the risk of ink mist flowing into the channel 700.

[0144] Here, the path of the airflow passing through the first wind tunnel WT1 is referred to as the first path, the path of the airflow passing through the second wind tunnel WT2 is referred to as the second path, and the path of the airflow passing through the third wind tunnel WT3 is referred to as the third path. That is, the first wind tunnel WT1 guides the airflow to the first path, the second wind tunnel WT2 guides the airflow to the second path, and the third wind tunnel WT3 guides the airflow to the third path. The first path, the second path, and the third path are all different paths. The cooling unit 6 can adjust the amount of air passing through the first path, i.e., the airflow to the first wind tunnel WT1, by adjusting either or both of the intake-side adjustment unit RVi1 and the exhaust-side adjustment unit RVO1. Similarly, the cooling unit 6 can adjust the amount of air passing through the second path, i.e., the airflow to the second wind tunnel WT2, by adjusting either or both of the intake-side adjustment unit RVi2 and the exhaust-side adjustment unit RVO2. Furthermore, the cooling unit 6 can adjust the amount of air passing through the third path, i.e., the airflow to the third wind tunnel WT3, by adjusting either or both of the intake-side adjustment unit RVi3 and the exhaust-side adjustment unit RVO3. With this configuration, the cooling unit 6 can adjust the cooling rates of the head drive module 10-1, head drive module 10-2, and head drive module 10-3.

[0145] The intake-side adjustment units RVi1, RVi2, RVi3 and the exhaust-side adjustment units RVO1, RVO2, RVO3 can be configured for manual adjustment or for adjustment based on a cooling control signal output by the control unit 2. Alternatively, some of the intake-side adjustment units RVi1, RVi2, RVi3 and the exhaust-side adjustment units RVO1, RVO2, RVO3 can be adjusted manually, while others are adjusted based on a cooling control signal. In the case where at least a portion of the intake-side adjustment units RVi1, RVi2, RVi3 and the exhaust-side adjustment units RVO1, RVO2, RVO3 are adjusted via a cooling control signal, i.e., under the control of the control unit 2, they are adjusted, for example, based on the heat generated by the head drive module 10. In this case, by installing temperature sensors in each head drive module 10, the heat generated by each head drive module 10 can be detected. Then, based on the detected heat generation, the control unit 2 adjusts at least a portion of the intake-side adjustment sections RVi1, RVi2, RVi3 and the exhaust-side adjustment sections RVO1, RVO2, RVO3. Specifically, the control unit 2 outputs a cooling control signal to the cooling unit 6 to increase the airflow to the wind tunnel where the head drive module 10, which has a high heat generation, is located. For example, when the heat generation of the head drive module 10-1 is greater than that of the head drive module 10-2, the control unit 2 controls the intake-side adjustment sections RVi1, RVi2 and the exhaust-side adjustment sections RVO1, RVO2 to make the airflow to the first wind tunnel WT1 greater than that to the second wind tunnel WT2. Alternatively, since the heat generation of the head drive module 10 varies according to the pattern of the image formed on the medium P, the control unit 2 can also adjust at least a portion of the intake-side adjustment sections RVi1, RVi2, RVi3 and the exhaust-side adjustment sections RVO1, RVO2, RVO3 based on the image information signal IP.

[0146] Figures 15-17 This diagram shows the head unit 5 and the cooling unit 6. Figure 15 This is the main view viewed from the -X2 side. Figure 16 This is a side view taken from the +Y2 side. Figure 17 This is a stereoscopic view taken from approximately the +x2 side. Figure 15 In the diagram, the outline of the outer casing HS is shown with a double-dotted line.

[0147] It should be noted that the liquid ejection module 20 and wiring component 30 connected to the head drive module 10-1 are referred to as liquid ejection module 20-1 and wiring component 30-1, respectively, and the head unit 5, which includes the head drive module 10-1, liquid ejection module 20-1, and wiring component 30-1, is referred to as head unit 5-1. Similarly, the liquid ejection module 20 and wiring component 30 connected to the head drive module 10-2 are referred to as liquid ejection module 20-2 and wiring component 30-2, respectively, and the head unit 5, which includes the head drive module 10-2, liquid ejection module 20-2, and wiring component 30-2, is referred to as head unit 5-2. Furthermore, the liquid ejection module 20 and wiring component 30 connected to the head drive module 10-3 are referred to as liquid ejection module 20-3 and wiring component 30-3, respectively, and the head unit 5, which includes the head drive module 10-3, liquid ejection module 20-3, and wiring component 30-3, is referred to as head unit 5-3.

[0148] like Figure 15 As shown, the cooling unit 6 is installed inside the housing HS in the head units 5-1, 5-2, and 5-3. The openings on the +Y2 side of the common intake duct WTi and the common exhaust duct WTo of the channel 700 are both exposed from the +Y side of the housing HS. That is, the channel 700 is connected to the outside of the housing HS via the common intake duct WTi and the common exhaust duct WTo.

[0149] like Figures 15-17As shown, the ends of the head drive modules 10-1, 10-2, and 10-3, disposed inside the channel 700, on the -Z2 side, protrude to the outside of the channel 700 on the -X2 side, i.e., the outside of the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3. Furthermore, the liquid ejection module 20-1 is disposed outside the first wind tunnel WT1 and connected to the head drive module 10-1 via the wiring member 30-1. Similarly, the liquid ejection module 20-2 is disposed outside the second wind tunnel WT2 and connected to the head drive module 10-2 via the wiring member 30-2. Additionally, the liquid ejection module 20-3 is disposed outside the third wind tunnel WT3 and connected to the head drive module 10-3 via the wiring member 30-3. Thus, the head drive modules 10-1, 10-2, and 10-3 are disposed inside the channel 700, while the liquid ejection modules 20-1, 20-2, and 20-3 are disposed outside the channel 700. In other words, the head drive module 10 and the liquid ejection module 20 are separated by the channel 700. Therefore, the risk of ink mist generated from the liquid ejection module 20 adhering to the head drive module 10 and causing a short circuit within the head drive module 10 is reduced. Furthermore, since the liquid ejection module 20 is disposed inside the housing HS, the risk of ink mist being drawn into the channel 700 is further reduced because air from outside the housing HS is drawn into the channel 700. Additionally, since the head drive module 10 and the liquid ejection module 20 are separated by the channel 700, collisions between the cooling airflow and the ink ejected from the liquid ejection module 20 are suppressed. Therefore, the accuracy of the ink droplet position on the medium P, i.e., the ejection position, can be improved. Moreover, since the air within the channel 700 is exhausted to the outside of the housing HS, collisions between the cooling airflow and the ink ejected from the liquid ejection module 20 are further suppressed.

[0150] 6. Variations

[0151] The embodiments of the disclosed invention have been described in detail above with reference to the accompanying drawings. However, the specific configuration is not limited to the embodiments described above. As long as the spirit of the disclosure is not departed, changes, substitutions, deletions, etc., can be made. For example, the following changes can be made.

[0152] In the above embodiment, a configuration was described in which the cooling unit 6 draws in air from outside the housing HS to cool the head drive module 10, but the configuration is not limited to this. For example, the cooling unit 6 may also be configured to have a channel 701 as a closed loop instead of a channel 700 communicating with the outside of the housing HS. Figure 18As shown, the channel 701 includes a first wind tunnel WT1, a second wind tunnel WT2, and a third wind tunnel WT3. Head drive modules 10-1, 10-2, and 10-3, disposed in these wind tunnels, are cooled by air circulating within the channel 701. In this configuration, the cooling unit 6 also includes, for example, a heat exchange section HE, a coolant tank CLT, and a radiator RD. Furthermore, the air within the channel 701, whose temperature has risen due to the cooling of the head drive module 10, is cooled by heat exchange between the heat exchange section HE and coolant supplied from the coolant tank CLT. The cooled coolant, after heat exchange, is cooled by the radiator RD and returned to the coolant tank CLT. According to this configuration, since external air is not drawn into the channel 701, the risk of ink mist flowing into the channel 701 can be further reduced.

[0153] In the above embodiment, airflow is generated in the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3 by a set of intake fans FNi and exhaust fans FNo, but this configuration is not limited to. For example, it is also possible to configure each of the first wind tunnel WT1, the second wind tunnel WT2, and the third wind tunnel WT3 to have one or both of the intake fans FNi and exhaust fans FNo separately. Moreover, if the rotational speed, i.e., the air volume, of each intake fan FNi and each exhaust fan FNo can be changed by the control unit 2, it is not necessary to have an adjustment valve for each wind tunnel. In this case, the intake fans FNi and the exhaust fans FNo act as adjustment units.

[0154] In the above embodiment, an example is shown where multiple head units 5 ejecting ink of the same color are arranged in a row along the Y2 direction. However, in the case where the liquid ejection device 1 ejects ink of multiple colors, the row heads of each color can also be arranged in the X2 direction. In this case, the multiple head units 5 are arranged in a matrix when viewed from the Z2 direction. Furthermore, in such a configuration, all head drive modules 10 of all head units 5 can be cooled by a shared cooling unit 6. That is, all head drive modules 10 can be arranged within a shared channel 700. Alternatively, the liquid ejection device 1 can be configured such that each color has a cooling unit 6, and the multiple cooling units 6 are arranged in the X2 direction.

[0155] It should be noted that the items described above can be combined arbitrarily.

[0156] 7. Effects

[0157] As described above, the liquid ejection device according to the embodiment includes: a first drive circuit for generating a first drive signal; a second drive circuit for generating a second drive signal; a first ejection section for ejecting liquid to a medium based on the first drive signal; a second ejection section for ejecting liquid to a medium based on the second drive signal; an air supply section for generating airflow; a first wind tunnel for guiding the airflow to a first path; and a second wind tunnel for guiding the airflow to a second path different from the first path. The first drive circuit is disposed inside the first wind tunnel, the second drive circuit is disposed inside the second wind tunnel, and the first ejection section and the second ejection section are disposed outside the first wind tunnel and the second wind tunnel, respectively.

[0158] According to this configuration, since the first and second ejection sections, which may generate ink mist, are separated from the first and second drive circuits, which may short-circuit due to ink mist, by the first and second wind tunnels respectively, the possibility of short circuits occurring in the first and second drive circuits can be reduced. Furthermore, since the first and second drive circuits are arranged in different wind tunnels, even if ink mist enters one wind tunnel, the possibility of short circuits occurring in the drive circuit arranged in the other wind tunnel can be reduced. Additionally, since the cooling is based on air cooling, even if the first and second drive circuits have electronic components such as coils or capacitors protruding from the substrate, they can be effectively cooled.

[0159] It should be noted that, in the examples described above, the liquid ejection device 1 is one example of such a liquid ejection device. Furthermore, in the examples described above, the drive circuit section DRV included in the head drive module 10-1 is one example of such a first drive circuit. Furthermore, in the examples described above, the drive signals COMA, COMB, and COMC output by the drive circuit section DRV of the head drive module 10-1 are one example of such a first drive signal. Furthermore, in the examples described above, the drive circuit section DRV included in the head drive module 10-2 is one example of such a second drive circuit. Furthermore, in the examples described above, the drive signals COMA, COMB, and COMC output by the drive circuit section DRV of the head drive module 10-2 are one example of such a second drive signal. Furthermore, in the examples described above, the ejection section 600 included in the liquid ejection module 20-1 is one example of such a first ejection section. Furthermore, in the examples described above, the ejection section 600 included in the liquid ejection module 20-2 is one example of such a second ejection section. Furthermore, in the examples described above, the intake fan FNi and the exhaust fan FNo are examples of this air supply unit. Also, in the examples described above, the first wind tunnel WT1 is an example of this first wind tunnel. Furthermore, in the examples described above, the second wind tunnel WT2 is an example of this second wind tunnel.

[0160] In addition, the liquid ejection device according to the embodiment also includes an adjustment unit that adjusts the air volume supplied to the first wind tunnel and the air volume supplied to the second wind tunnel.

[0161] According to this configuration, the airflow to the first wind tunnel and the airflow to the second wind tunnel can be adjusted based on the heat generated by the first and second drive circuits, thus effectively cooling the first and second drive circuits. It should be noted that in the example described above, at least one of the intake-side adjustment units RVi1 and RVi2 and the exhaust-side adjustment units RVO1 and RVO2 is an example of this adjustment unit.

[0162] In addition, the liquid ejection device according to the embodiment also includes a control unit, which controls the adjustment unit when the heat generated by the first drive circuit is greater than the heat generated by the second drive circuit, so that the air volume supplied to the first wind tunnel is greater than the air volume supplied to the second wind tunnel.

[0163] According to this configuration, since the control unit increases the airflow to the wind tunnel where the drive circuit with high heat generation is located, the cooling of the first drive circuit and the second drive circuit can be effectively achieved. It should be noted that, in the example described above, control unit 2 is an example of this control unit.

[0164] In addition, the liquid ejection device according to the embodiment also includes a housing, which encloses the first drive circuit, the second drive circuit, the first ejection part and the second ejection part. The first wind tunnel and the second wind tunnel form a channel disposed inside the housing, and the channel has an air intake for drawing air in from the outside of the housing.

[0165] According to this configuration, air located outside the housing containing the first and second ejector portions is drawn into the interior of the channel, thereby reducing the impact of ink mist on the first and second drive circuits. It should be noted that, in the example described above, the housing HS is one example of such a housing. Furthermore, in the example described above, the channel 700 is one example of such a channel. Additionally, in the example described above, the common air intake tunnel WTi is one example of such an air intake.

[0166] Furthermore, in the liquid ejection device according to the embodiment, the channel is provided with an exhaust port for discharging air to the outside of the housing.

[0167] According to this configuration, since air is exhausted to the outside of the outer casing containing the first and second ejector portions, the impact of exhaust from the channel on the liquid ejected from the first and second ejector portions can be reduced, thereby improving the accuracy of the liquid ejection position on the medium P. It should be noted that, in the example described above, the shared exhaust wind tunnel WTo is an example of this exhaust port.

[0168] Furthermore, in the liquid ejection device according to the embodiment, the air supply section includes a first air supply section that draws in air from the air inlet and a second air supply section that discharges air from the air outlet, wherein the air supply volume of the first air supply section is greater than the air supply volume of the second air supply section.

[0169] According to this configuration, since the inside of the channel becomes positively pressured, the possibility of ink mist seeping into the channel is reduced. Therefore, the impact of ink mist on the first and second drive circuits can be reduced. It should be noted that in the example described above, the intake fan FNi is an example of this first air supply unit. Furthermore, in the example described above, the exhaust fan FNo is an example of this second air supply unit.

[0170] In addition, the liquid ejection device involved in the modified example also includes a heat exchange section for heat exchange, wherein the first wind tunnel and the second wind tunnel constitute a channel, which is a closed loop for air circulation, and the air in the channel is cooled by the heat exchange section.

[0171] According to this configuration, since the channel is a closed loop, the risk of ink mist flowing into the channel can be further reduced. It should be noted that, in the example described above, the heat exchange unit HE is one example of such a heat exchange unit. Furthermore, in the example described above, channel 701 is one example of such a channel.

[0172] Furthermore, in the liquid ejection device according to the embodiment, the first drive circuit is included in a first module having a first substrate, the first ejection portion is included in a second module having a second substrate, and the first substrate and the second substrate are connected in a BtoB manner.

[0173] According to this configuration, since the first substrate containing the first module of the first driving circuit and the second substrate containing the second module of the first ejection section are connected in a B2B manner, the propagation path of the first driving signal is shortened, reducing the risk of first driving signal malfunction. It should be noted that in the example described above, the head driving module 10-1 is an example of this first module. Furthermore, in the example described above, the liquid ejection module 20-1 is an example of this second module. Additionally, in the example described above, the first circuit board B1 of the head driving module 10-1 is an example of this first substrate. Furthermore, in the example described above, the assembly substrate 33 of the liquid ejection module 20-1 is an example of this second substrate.

[0174] Furthermore, the cooling unit involved in the embodiment is a cooling unit installed on the first head unit and the second head unit. The first head unit has a first drive circuit that generates a first drive signal and a first ejector that sprays liquid onto the medium based on the first drive signal. The second head unit has a second drive circuit that generates a second drive signal and a second ejector that sprays liquid onto the medium based on the second drive signal. The cooling unit includes: an air supply section that generates airflow; a first wind tunnel that guides the airflow to a first path; and a second wind tunnel that guides the airflow to a second path different from the first path. The first drive circuit is disposed inside the first wind tunnel, the second drive circuit is disposed inside the second wind tunnel, and the first ejector and the second ejector are disposed outside the first wind tunnel and the second wind tunnel.

[0175] According to this configuration, the first and second ejection sections, which may generate ink mist, can be separated from the first and second drive circuits, which may short-circuit due to ink mist, into different spaces via the first and second wind tunnels. This reduces the likelihood of short circuits occurring in the first and second drive circuits. Furthermore, since the first and second drive circuits are arranged in different wind tunnels, even if ink mist enters one wind tunnel, the likelihood of short circuits occurring in the drive circuit arranged in the other wind tunnel can be reduced. Additionally, because the cooling is based on air cooling, even if the first and second drive circuits have electronic components such as coils or capacitors protruding from the substrate, they can be effectively cooled.

[0176] It should be noted that, in the examples described above, cooling unit 6 is one example of a cooling unit. Furthermore, in the examples described above, the drive circuit section DRV included in head drive module 10-1 is one example of a first drive circuit. Additionally, in the examples described above, the drive signals COMA, COMB, and COMC output by the drive circuit section DRV of head drive module 10-1 are one example of a first drive signal. Furthermore, in the examples described above, the drive circuit section DRV included in head drive module 10-2 is one example of a second drive circuit. Furthermore, in the examples described above, the drive signals COMA, COMB, and COMC output by the drive circuit section DRV of head drive module 10-2 are one example of a second drive signal. Furthermore, in the examples described above, the ejection section 600 included in liquid ejection module 20-1 is one example of a first ejection section. Furthermore, in the examples described above, the ejection section 600 included in liquid ejection module 20-2 is one example of a second ejection section. Furthermore, in the examples described above, the intake fan FNi and the exhaust fan FNo are examples of this air supply unit. Also, in the examples described above, the first wind tunnel WT1 is an example of this first wind tunnel. Furthermore, in the examples described above, the second wind tunnel WT2 is an example of this second wind tunnel.

Claims

1. A liquid ejection device, characterized in that, include: The first driving circuit generates the first driving signal; The second driving circuit generates the second driving signal; The first ejection section ejects liquid into the medium based on the first driving signal; The second ejector section ejects liquid into the medium based on the second drive signal; The air supply section generates airflow; The first wind tunnel guides the airflow to the first path; as well as The second wind tunnel guides the airflow to a second path different from the first path, and the first drive circuit is configured inside the first wind tunnel. The second drive circuit is configured inside the second wind tunnel. The first ejector and the second ejector are disposed outside the first wind tunnel and the second wind tunnel.

2. The liquid ejection device according to claim 1, characterized in that, The liquid ejection device further includes an adjustment unit, which adjusts the air volume supplied to the first wind tunnel and the air volume supplied to the second wind tunnel.

3. The liquid ejection device according to claim 2, characterized in that, The liquid ejection device further includes a control unit, which controls the adjustment unit to make the air volume supplied to the first wind tunnel greater than the air volume supplied to the second wind tunnel when the heat generation of the first drive circuit is greater than that of the second drive circuit.

4. The liquid ejection device according to claim 1, characterized in that, The liquid ejection device further includes a housing, which encloses the first driving circuit, the second driving circuit, the first ejection part, and the second ejection part. The first wind tunnel and the second wind tunnel constitute a passageway disposed inside the outer shell. The channel has an air intake for drawing air in from the outside of the housing.

5. The liquid ejection device according to claim 4, characterized in that, The channel has an exhaust port for discharging air to the outside of the housing.

6. The liquid ejection device according to claim 5, characterized in that, The air supply unit includes a first air supply unit that draws in air from the air intake and a second air supply unit that discharges air from the air exhaust port. The air volume supplied by the first air supply section is greater than that supplied by the second air supply section.

7. The liquid ejection device according to claim 1, characterized in that, The liquid ejection device also includes a heat exchange section for heat exchange. The first wind tunnel and the second wind tunnel form a passage. The channel is a closed loop for air circulation. The air inside the channel is cooled by the heat exchange unit.

8. The liquid ejection device according to claim 1, characterized in that, The first driving circuit is included in a first module having a first substrate. The first ejection portion is included in the second module having the second substrate. The first substrate and the second substrate are connected in a B2B manner.

9. A cooling unit, characterized in that, It is a cooling unit installed on a first head unit and a second head unit. The first head unit includes a first drive circuit that generates a first drive signal and a first ejector that sprays liquid into a medium based on the first drive signal. The second head unit includes a second drive circuit that generates a second drive signal and a second ejector that sprays liquid into a medium based on the second drive signal. The cooling unit includes: The air supply section generates airflow; A first wind tunnel guides the airflow to a first path; and The second wind tunnel guides the airflow to a second path different from the first path, and the first drive circuit is configured inside the first wind tunnel. The second drive circuit is configured inside the second wind tunnel. The first ejector and the second ejector are disposed outside the first wind tunnel and the second wind tunnel.

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