JP2018099868A - Liquid discharge device and circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge device which reduces the possibility such that signal deterioration of a residual vibration signal occurs, and can accurately detect a state of a discharge section.SOLUTION: A liquid discharge device includes a first discharge section which includes a first piezoelectric element and operates based on a first driving signal driving the first piezoelectric element, a circuit substrate 470 which transfers the first driving signal and a first residual vibration signal indicating first residual vibration generated after the first piezoelectric element is driven by the first driving signal, and a determination circuit determining a state of the first discharge section based on the first residual vibration signal, where the circuit board includes a first wiring 415 transferring the first residual vibration signal, a second wiring transferring the first driving signal, a first input terminal which is connected to the first wiring and inputs the first residual vibration signal to the circuit board, and a first output terminal which is connected to the first wiring and outputs the first residual vibration signal to the determination circuit, the first wiring, the first input terminal and the first output terminal 405 are formed on a first layer 471 of the circuit board, and the second wiring is provided on a second layer different from the first layer.SELECTED DRAWING: Figure 16

Description

  The present invention relates to a liquid ejection device and a circuit board.

  As a liquid ejecting apparatus such as an ink jet printer that ejects ink and prints an image or a document, an apparatus using a piezoelectric element (for example, a piezoelectric element) is known. The piezoelectric element is provided corresponding to each of the plurality of ejection units in the head (inkjet head), and is driven at a predetermined timing from the nozzle of the ejection unit by being driven according to the drive signal output from the control board. A certain amount of ink (liquid) is ejected to form dots. Patent Document 1 discloses a relay board provided with wiring for transmitting a signal for driving a head from a control board to an ejection head.

JP 2014-188914 A

  The signal transmitted between the control board and the ejection head includes a drive signal for driving a piezoelectric element provided corresponding to the nozzle, a control signal for controlling application of the drive signal to the piezoelectric element, and a signal for the ejection head. A detection signal for detecting residual vibration and determining a discharge state is included. In a circuit board on which wiring for transferring these signals is formed, the signal may be deteriorated during signal transfer depending on the wiring layout.

  If signal detection occurs in the detection signal, the state of the discharge unit cannot be accurately determined, and an extra maintenance process may be performed by erroneously determining the state of the discharge unit.

  The present invention has been made in view of the above problems, and according to some aspects of the present invention, it is possible to reduce the risk of signal deterioration of the residual vibration signal based on the residual vibration of the ejection head in the circuit board. In addition, it is possible to provide a liquid ejection apparatus that can detect the state of the ejection section with high accuracy. In addition, according to some aspects of the present invention, it is possible to provide a circuit board that can reduce the possibility of signal degradation of the residual vibration signal.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
The liquid discharge apparatus according to this application example includes a first piezoelectric element, and operates based on a first drive signal that drives the first piezoelectric element, the first drive signal, and the first drive signal. A circuit board for transferring a first residual vibration signal indicating a first residual vibration generated after the piezoelectric element is driven by the first drive signal; and the first ejection unit based on the first residual vibration signal. A determination circuit for determining a state, wherein the circuit board is connected to the first wiring for transferring the first residual vibration signal, the second wiring for transferring the first drive signal, and the first wiring. A first input terminal that inputs the first residual vibration signal to the circuit board; and a first output terminal that is connected to the first wiring and outputs the first residual vibration signal to the determination circuit; The first wiring, the first input terminal, and the first output terminal Is formed on the first layer of the circuit board, the second wiring is provided in a different second layer and the first layer.

  In the liquid ejection device according to this application example, the first wiring that transfers the first residual vibration signal and the second wiring that transfers the first drive signal are provided in different wiring layers on the circuit board. Therefore, according to the liquid ejection device according to this application example, in the circuit board, the first residual vibration signal transferred by the first wiring and the first driving signal transferred by the second wiring are affected by the mutual interference. It is possible to reduce the possibility that the one residual vibration signal is deteriorated, and it is possible to accurately detect the state of the first discharge unit.

  In the liquid ejection device according to this application example, in the circuit board, the first input terminal to which the first residual vibration signal is input, the first wiring to which the first residual vibration signal is transferred, and the first residual vibration signal Are provided on the same layer (first layer) of the circuit board. Therefore, a via or the like for connecting to another layer of the circuit board is not necessary, and the possibility that the first residual vibration signal is deteriorated can be further reduced, and the state of the first discharge portion can be detected with high accuracy. it can.

[Application Example 2]
In the liquid ejection apparatus according to the application example, the circuit board includes an AD conversion circuit that converts the first residual vibration signal into a digital signal, and the AD conversion circuit is provided in the first layer. The wiring may be connected to the first output terminal via the AD conversion circuit.

  In the liquid ejection device according to this application example, the first residual vibration signal output from the circuit board is converted into a digital signal and output. Therefore, it is possible to transfer the first residual vibration signal from the circuit board to the determination circuit with high accuracy, and the determination circuit can determine the state of the first ejection unit with higher accuracy.

[Application Example 3]
In the liquid ejection device according to the application example, the liquid ejection apparatus further includes a second ejection unit that includes a second piezoelectric element and operates by driving the second piezoelectric element, and the first wiring includes the first residual vibration signal, The second residual vibration signal indicating the second residual vibration generated after the second piezoelectric element is driven may be transferred in a time division manner.

  In the liquid ejection device according to this application example, the first wiring transfers the first residual vibration signal and the second residual vibration signal in a time division manner. As a result, the number of wires for transferring the residual vibration signal can be reduced, and the circuit board can be reduced in size.

[Application Example 4]
In the liquid ejection apparatus according to the application example, the circuit board includes a third layer different from the first layer and the second layer, and one end to which the first driving signal of the first piezoelectric element is applied. A third wiring that transfers a reference voltage signal that is applied to a different other end and supplies a reference voltage, and the third wiring is provided in the third layer, and in the plan view of the circuit board, The third wiring and the second wiring may be provided so that at least a part thereof overlaps.

In the liquid ejection apparatus according to this application example, the second wiring to which the first drive signal applied to one end of the piezoelectric element is transferred, and the third wiring to which the reference voltage signal applied to the other end of the piezoelectric element is transferred. Is provided so that at least a part thereof overlaps in a plan view of the circuit board, so that the electromagnetic fields generated by the currents flowing in the second wiring and the third wiring are canceled each other and the impedance of the wiring is reduced. It becomes possible to do. As a result, it is possible to reduce the possibility that at least one of the first drive signal and the reference voltage signal deteriorates, and the liquid can be ejected with high accuracy.

  Furthermore, in the liquid ejection device according to this application example, it is possible to reduce the possibility that at least one of the first drive signal and the reference voltage signal is deteriorated. Therefore, the voltage signal applied to the first piezoelectric element can be reduced. The accuracy is improved, and therefore the accuracy of the first residual vibration that occurs after the first piezoelectric element is driven is also improved, so there is a possibility that the state of the ejection unit can be detected with high accuracy.

[Application Example 5]
In the liquid ejection apparatus according to the application example, the circuit board includes a second drive signal that drives the first piezoelectric element, and the circuit board transfers a fourth wiring that transfers the second drive signal, the first layer, and the first layer And a fourth layer different from the third layer, wherein the fourth wiring is provided in the fourth layer, and the third layer is between the second layer and the fourth layer. The third wiring and the fourth wiring may be provided so that at least a part thereof overlaps in a plan view of the circuit board.

  In the liquid ejection device according to this application example, the fourth wiring to which the second drive signal for driving the first piezoelectric element is transferred and the third wiring to which the reference voltage signal is transferred are in plan view of the circuit board. By providing at least a part of them, it is possible to cancel the electromagnetic fields generated by the currents flowing in the fourth wiring and the third wiring, and to reduce the impedance of the wiring. It becomes. Accordingly, it is possible to further reduce the possibility that at least one of the second drive signal and the reference voltage signal is deteriorated, and the liquid can be ejected with high accuracy.

  Further, in the liquid ejection apparatus according to this application example, the third wiring that transfers the reference voltage signal includes a wiring area of the second wiring to which the first driving signal is transferred, and a fourth wiring to which the second driving signal is transferred. The wiring region is provided so that at least a part of the wiring region overlaps. That is, it is possible to reduce the difference in line length between the signal path through which the first drive signal is supplied to the first piezoelectric element and the signal path through which the second drive signal is supplied to the piezoelectric element. Accordingly, it is possible to reduce the impedance difference between the signal path through which the first drive signal is supplied to the piezoelectric element and the signal path through which the second drive signal is supplied to the piezoelectric element, and at least the first drive signal and the second drive signal can be reduced. It is possible to reduce the risk of one being deteriorated, and liquid can be discharged with high accuracy.

  Furthermore, in the liquid ejection device according to this application example, since it is possible to reduce the possibility that at least one of the first drive signal, the second drive signal, and the reference voltage signal is deteriorated, it is applied to the first piezoelectric element. Therefore, the accuracy of the first residual vibration that occurs after the first piezoelectric element is driven is improved, so that the state of the ejection unit may be detected with high accuracy.

[Application Example 6]
The circuit board according to this application example detects the first residual vibration generated after the first piezoelectric element is driven by the first drive signal, and transfers the first residual vibration signal indicating the first residual vibration. A wiring, a second wiring for transferring the first drive signal for driving the first piezoelectric element, a first input terminal connected to the first wiring for inputting the first residual vibration signal, and the first A first output terminal that is connected to a wiring and outputs the first residual vibration signal, wherein the first wiring, the first input terminal, and the first output terminal are formed in a first layer, and The second wiring is provided on a second layer different from the first layer.

In the circuit board according to this application example, the first wiring that transfers the first residual vibration signal and the second wiring that transfers the first drive signal are provided in different wiring layers. Therefore, according to the circuit board according to this application example, the first residual vibration signal is generated due to the mutual interference between the first residual vibration signal transferred by the first wiring and the first drive signal transferred by the second wiring. The possibility of deterioration can be reduced, and the state of the first discharge unit can be detected with high accuracy.

  In the circuit board according to this application example, the first input terminal to which the first residual vibration signal is input, the first wiring to which the first residual vibration signal is transferred, and the first output terminal that outputs the first residual vibration signal Are provided on the same layer (first layer) of the circuit board. Therefore, a via or the like for connecting to another layer of the circuit board is not necessary, and the possibility that the first residual vibration signal is deteriorated can be further reduced, and the state of the first discharge portion can be detected with high accuracy. it can.

It is a top view which shows schematic structure of a liquid discharge apparatus. It is a side view which shows schematic structure of a liquid discharge apparatus. It is a top view which shows the nozzle surface of a head unit. It is a block diagram which shows the electrical structure of a liquid discharge apparatus. It is a block diagram which shows the electrical structure of a liquid discharge apparatus. It is a figure which shows the structure of the discharge part in a head. It is a figure which shows the waveform of the drive signals COMA and COMB. It is a figure which shows the waveform of the drive voltage Vout. It is a figure which shows the structure of the selection control part in a head unit. It is a figure which shows the decoding content of the decoder in a head unit. It is a figure which shows the structure of the selection part in a head unit. It is a figure for demonstrating operation | movement of the selection control part in a head unit, and a selection part. It is a figure which shows the structure of the switching part in a head unit. It is a figure which shows an example of the waveform of the switching period designation | designated signal RT in a test | inspection period, the drive voltage Vout applied to the discharge part to be test | inspected, and the residual vibration signal Vrb. It is a disassembled perspective view which shows schematic structure of a head unit. It is a figure which shows roughly an example of a structure of the 1st wiring layer of the relay substrate in 1st Embodiment. It is a figure which shows roughly an example of a structure of the 2nd wiring layer of the relay substrate in 1st Embodiment. It is a figure which shows roughly an example of a structure of the 3rd wiring layer of the relay substrate in 1st Embodiment. It is a figure which shows roughly an example of a structure of the 4th wiring layer of the relay substrate in 1st Embodiment. It is a figure which shows roughly an example of a structure of the 5th wiring layer of the relay substrate in 1st Embodiment. It is a figure which shows roughly an example of a structure of the 6th wiring layer of the relay substrate in 1st Embodiment. It is a block diagram which shows the electrical structure of the liquid discharge apparatus of 2nd Embodiment. It is a figure which shows roughly an example of a structure of the 1st wiring layer of the relay substrate in 2nd Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The drawings used are for convenience of explanation. The embodiments described below do not unduly limit the contents of the present invention described in the claims. Also, not all of the configurations described below are essential constituent requirements of the present invention.

1. First Embodiment 1.1 Outline of Liquid Ejecting Apparatus A printing apparatus as an example of a liquid ejecting apparatus according to the present embodiment ejects ink in accordance with image data supplied from an external host computer, thereby making paper Ink jet printers that form ink dots on a print medium such as the above and thereby print an image (including characters, graphics, etc.) according to the image data. In addition to the printing device such as a printer, the liquid ejection device is used for forming electrodes of a color material ejection device, an organic EL display, an FED (surface emitting display), etc. used for manufacturing a color filter such as a liquid crystal display. Electrode material discharge device, bio-organic matter discharge device used for biochip manufacturing, three-dimensional modeling device (so-called 3D printer), textile printing device, and the like.

  FIG. 1 is a plan view schematically showing the liquid ejection device 1, and FIG. 2 is a side view of the liquid ejection device 1. Here, the width direction of the liquid ejection apparatus 1 (the direction from the bottom to the top in FIG. 1) is referred to as a “first direction X”. A direction from the first driven roller 43 toward the second transport roller 72 is referred to as a “second direction Y”. Further, the height direction of the liquid ejection apparatus 1 (the direction perpendicular to the paper surface in FIG. 1) intersecting both the first direction X and the second direction Y is referred to as a “third direction Z”. In the present embodiment, the relationship between the orientations (X, Y, Z) is orthogonal, but the arrangement of the components is not necessarily limited to being orthogonal.

  The liquid ejection apparatus 1 according to the present embodiment is a line head type inkjet printer that performs printing only by transporting a recording sheet S that is an ejection target medium.

  The liquid ejection apparatus 1 includes a plurality of head units 32, a base 3 on which the head units 32 are mounted, a liquid storage unit 4 such as an ink tank that stores ink, a first transport unit 5, and a second transport unit 6. And the apparatus main body 7.

  As shown in FIG. 3, the head unit 32 includes a plurality of drive units 320 (320-1 to 320-4) in the width direction (first direction X) of the recording sheet S that intersects the conveyance direction of the recording sheet S. Are lined up. In addition, on the surface facing each recording unit S in each drive unit 320 (third direction Z), a large number of nozzles 651 that eject ink provided in the drive unit 320 are arranged in the first direction X at predetermined intervals. Are lined up. 3 virtually shows the positions of the drive unit 320 and the nozzle 651 when the head unit 32 is viewed from the third direction Z. The positions of the nozzles 651 at the ends of the drive units 320 (for example, the drive unit 320-1 and the drive unit 320-2) adjacent in the second direction Y are at least partially overlapped, and the third of the head unit 32. On the surface on the direction Z side, nozzles 651 are arranged in the first direction X at predetermined intervals over the width of the recording sheet S. That is, the liquid ejecting apparatus 1 prints on the recording sheet S when the head unit 32 ejects ink from the nozzles 651 to the recording sheet S conveyed without stopping under the head unit 32.

  In FIG. 3, four drive units 320 (320-1 to 320-4) are shown as four drive units 320 belonging to the head unit 32 for the sake of space, but the present invention is not limited to this. That is, the drive unit 320 may be more or less than four. Moreover, although the drive unit 320 of FIG. 3 is arrange | positioned at zigzag form, it is not restricted to such arrangement | positioning.

  Returning to FIGS. 1 and 2, the base 3 holds two head units 32 arranged in parallel in the second direction Y.

The liquid storage unit 4 supplies ink to the head unit 32. In the present embodiment, the liquid storage unit 4 is fixed to the apparatus main body 7 and supplies ink from the liquid storage unit 4 to the head unit 32 via a supply pipe 8 such as a tube.

  The first transport unit 5 is provided on one side of the head unit 32 in the second direction Y. The first transport unit 5 includes a first transport roller 42 and a first driven roller 43 that is driven by the first transport roller 42. The first transport roller 42 is provided on the back surface S 2 side opposite to the landing surface S 1 on which the ink of the recording sheet S is landed, and is driven by the driving force of the first drive motor 41. The first driven roller 43 is provided on the landing surface S1 side of the recording sheet S, and sandwiches the recording sheet S with the first conveying roller 42. Such a first driven roller 43 presses the recording sheet S toward the first transport roller 42 by an urging member such as a spring (not shown).

  The second transport unit 6 includes a second drive motor 71, a second transport roller 72, a second driven roller 73, a transport belt 74, and a tension roller 75.

  The second transport roller 72 is driven by the driving force of the second drive motor 71. The conveyor belt 74 is an endless belt, and is hung on the outer periphery of the second conveyor roller 72 and the second driven roller 73. Such a conveyance belt 74 is provided on the back surface S2 side of the recording sheet S. The tension roller 75 is provided between the second conveyance roller 72 and the second driven roller 73, contacts the inner peripheral surface of the conveyance belt 74, and is applied to the conveyance belt 74 by the urging force of the urging member 76 such as a spring. Tension is applied. As a result, the surface of the conveyor belt 74 facing the head unit 32 between the second conveyor roller 72 and the second driven roller 73 is flat.

  That is, in the liquid ejection apparatus 1 in the present embodiment, the recording sheet S is transported in the second direction Y by the first transport unit 5 and the second transport unit 6. Then, printing is performed by ejecting ink from the head unit 32 and landing the ejected ink on the landing surface S1 of the recording sheet S.

  In the present embodiment, the liquid ejection apparatus 1 is exemplified by a line head type ink jet printer in which the head unit 32 is fixed to the apparatus main body 7 and printing is performed simply by conveying the recording sheet S. For example, the head unit 32 is mounted on a carriage that moves in a first direction X that intersects the second direction Y, which is the conveyance direction of the recording sheet S, and the head unit 32 is mounted in the first direction X. It may be a serial type ink jet printer that performs printing while moving to.

1.2 Electrical Configuration of Liquid Ejecting Device FIGS. 4 and 5 are block diagrams showing an electrical configuration of the liquid ejecting device 1.

  As described above, the liquid ejection apparatus 1 according to the present embodiment includes the two head units 32. Since these have the same configuration, the single head unit 32 is representative in FIGS. Thus, the illustration and description of the remaining head unit 32 are omitted.

  As shown in FIG. 4, the liquid ejection apparatus 1 includes a control unit 10 and a head unit 32. The control unit 10 and the head unit 32 are electrically connected via control signal connectors 170 and 280, drive signal connectors 180 and 290, and flexible flat cables 190 and 191.

  The control unit 10 includes a control unit 100, a first transport motor driver 40, a second transport motor driver 70, a control signal transmission unit 110, a state signal determination unit 120, and a drive circuit 50. .

  When various signals such as image data are supplied from the host computer, the control unit 100 outputs various control signals for controlling each unit.

  Specifically, the control unit 100 supplies a control signal Ctr1 to the first transport motor driver 40. The first transport motor driver 40 drives the first drive motor 41 in accordance with the control signal Ctr1. Further, the control unit 100 supplies a control signal Ctr2 to the second transport motor driver 70. The second transport motor driver 70 drives the second drive motor 71 according to the control signal Ctr2. The first drive motor 41 and the second drive motor 71 drive the first drive motor 41 and the second drive motor 71 based on a control signal from the control unit 100 to convey the recording sheet S in a predetermined direction.

  Further, the control unit 100, as a plurality of types of original control signals for controlling the driving of the piezoelectric element 60 (see FIG. 5) provided in the ejection unit 600 (see FIG. 5), based on various signals from the host computer. An original clock signal sSck, an original print data signal sSI, an original latch signal sLAT, an original change signal sCH, and an original switching period designation signal sRT are generated and output to the control signal transmission unit 110 in parallel format. Note that the plurality of types of original control signals may not include some of these signals, or may include other signals.

  In addition, the control unit 100 supplies the drive circuit 50 with digital data dA1, dB1, dA2, dB2, dA3, dB3, dA4, and dB4.

  Further, the control unit 100 causes the maintenance unit 80 to perform a maintenance process for recovering the ink ejection state in the ejection unit 600 normally. As a maintenance process, the maintenance unit 80 performs a cleaning process (pumping process) for sucking thickened ink, bubbles, or the like in the discharge unit 600 with a tube pump (not shown), and paper dust adhering to the vicinity of the nozzle of the discharge unit 600. A wiping process of wiping off foreign matters such as the above with a wiper is performed.

  The control signal transmission unit 110 receives a plurality of types of original control signals (original clock signal sSck, original print data signal sSI, original latch signal sLAT, original change signal sCH, and original switching period designation signal sRT) supplied from the control unit 100. Conversion (serialization) into one serial format serial control signal. At this time, a transfer clock signal used for high-speed serial data transfer is embedded in the serial control signal together with a plurality of types of original control signals.

  Further, the control signal transmission unit 110 converts the converted serial control signal into differential signals d1, d2, d3, d4 and outputs them. The control signal transmission unit 110 converts, for example, a serial control signal into differential signals d1, d2, d3, and d4 of an LVDS (Low Voltage Differential Signaling) transfer method and outputs the differential signals. Since the differential signal of the LVDS transfer system has an amplitude of about 350 mV, high-speed data transfer can be realized. The differential signals d1, d2, d3, and d4 may be differential signals of various high-speed transfer methods such as LVPECL (Low Voltage Positive Emitter Coupled Logic) and CML (Current Mode Logic) other than LVDS.

  That is, the control signal transmission unit 110 includes a plurality of types of original control signals (original clock signal sSck, original print data signal sSI, original latch signal sLAT, original change signal sCH, and original switching period designation signal sRT supplied from the control unit 100. ) To output differential signals d1, d2, d3, d4. Differential signals d1, d2, d3, and d4 based on the original control signal output from the control signal transmitting unit 110 are supplied to a control signal receiving unit 260 (see FIG. 5) provided in the head unit 32. In the present embodiment, each of the differential signals d1, d2, d3, and d4 is composed of a pair of differential signals.

  The state signal determination unit 120 (an example of a “determination circuit”) determines the state of the ejection unit 600 based on the residual vibration signal Vrbg supplied from the head unit 32. For example, the state signal determination unit 120 generates, for each ejection unit 600, a shaped waveform signal obtained by removing noise components from the residual vibration signal Vrbg using a low-pass filter or a band-pass filter, and the frequency (period) and amplitude of the shaped waveform signal. Or the like, and whether or not there is a discharge failure may be determined based on the measurement result.

  The control unit 100 also performs processing according to the determination result of the state signal determination unit 120. The control unit 100 may generate a control signal for causing the maintenance unit 80 to perform maintenance processing when the state signal determination unit 120 determines that there is an ejection failure. Further, for example, when the state signal determination unit 120 determines that there is a discharge failure, the control unit 100 records on the recording sheet S by the discharge unit 600 without discharge failure instead of the discharge unit 600 with discharge failure. An original print data signal sSI for performing complementary recording processing that complements (printing) may be generated. Even when a discharge abnormality occurs in the discharge unit 600, it is possible to continue the print process without stopping the print process and performing the maintenance process by executing the complementary recording process.

  The drive circuit 50 includes drive circuits 50-A1, 50-B1, 50-A2, 50-B2, 50-A3, 50-B3, 50-A4, and 50-B4.

  The drive circuit 50-A1 generates a drive signal COMA1 for driving the piezoelectric element 60 (see FIG. 5) provided in the head unit 32 based on the digital data dA1 output from the control unit 100, and the head unit 32.

  Specifically, if the input digital data dA1 is data obtained by analog / digital conversion of the waveform of the drive signal COMA1, the drive circuit 50-A1 converts the data dA1 into digital / analog. After the conversion, the drive signal COMA1 is generated by class D amplification and supplied to the head unit 32. For example, if the digital data dA1 is data that assumes a correspondence relationship with the slope of the drive signal COMA1, the drive circuit 50-A1 satisfies the correspondence relationship between the length and slope of each section defined by the data dA1. After generating the analog signal, the drive signal COMA1 is generated by class D amplification and supplied to the head unit 32.

  Note that the drive circuits 50-A1, 50-B1, 50-A2, 50-B2, 50-A3, 50-B3, 50-A4, and 50-B4 in this embodiment differ only in the output drive signals. The circuit configuration may be the same. Therefore, in the following description of the drive circuit 50-B1, 50-A2, 50-B2, 50-A3, 50-B3, 50-A4, 50-B4, digital data input to each drive circuit, and The generated drive signal will be described, and detailed description of the circuit will be omitted.

  The drive circuit 50-B1 generates a drive signal COMB1 for driving the piezoelectric element 60 (see FIG. 5) provided in the head unit 32 based on the digital data dB1 output from the control unit 100, and the head unit 32.

  The drive circuit 50-A2 generates a drive signal COMA2 for driving the piezoelectric element 60 (see FIG. 5) provided in the head unit 32 based on the digital data dA2 output from the control unit 100, and the head unit 32.

The drive circuit 50-B2 generates a drive signal COMB2 for driving the piezoelectric element 60 (see FIG. 5) provided in the head unit 32 based on the digital data dB2 output from the control unit 100, and the head unit 32.

  The drive circuit 50-A3 generates a drive signal COMA3 for driving the piezoelectric element 60 (see FIG. 5) provided in the head unit 32 based on the digital data dA3 output from the control unit 100, and the head unit 32.

  The drive circuit 50-B3 generates a drive signal COMB3 for driving the piezoelectric element 60 (see FIG. 5) provided in the head unit 32 based on the digital data dB3 output from the control unit 100, and the head unit 32.

  The drive circuit 50-A4 generates a drive signal COMA4 for driving the piezoelectric element 60 (see FIG. 5) provided in the head unit 32 based on the digital data dA4 output from the control unit 100, and the head unit 32.

  The drive circuit 50-B4 generates a drive signal COMB4 for driving the piezoelectric element 60 (see FIG. 5) provided in the head unit 32 based on the digital data dB4 output from the control unit 100, and the head unit 32.

  FIG. 5 is a diagram showing an electrical configuration of the head unit 32 of the present embodiment.

  The head unit 32 includes a control signal receiving unit 260, selection control units 210-1, 210-2, 210-3, 210-4, a plurality of selection units 230, and heads 20-1, 20-2, 20-. 3, 20-4, a switching unit 250, and an amplification output unit 240.

  The control signal receiving unit 260 receives the differential signals d1, d2, d3, and d4 based on the original control signal supplied from the control signal transmitting unit 110, and serially controls the received differential signals d1, d2, d3, and d4. Convert to signal. Thereafter, based on the converted serial control signal, control signals c1, c2, c3, and c4 for controlling the ejection of ink from the ejection unit 600 and a switching period designation signal RT are generated (restored), and the selection control unit 210 is generated. -1, 210-2, 210-3, 210-4 are supplied.

  Specifically, the control signal receiving unit 260 receives the differential signals d1, d2, d3, and d4 of the LVDS transfer method, and differentially amplifies the differential signals d1, d2, d3, and d4 into a serial control signal. Convert. Then, the transfer clock signal embedded in the serial control signal is restored, and based on the transfer clock signal, a plurality of types of original control signals (original clock signal sSck, original print data) included in the serial control signal are restored. By restoring (deserializing) the signal sSI, the original latch signal sLAT, the original change signal sCH, and the original switching period designation signal sRT, the control signals c1, c2, c3, and c4 and the switching period designation signal RT are generated. Then, the control signal receiving unit 260 sends the generated control signals c1, c2, c3, and c4 to the selection control units 210-1, 210-2, 210-3, and 210-4, and the switching period designation signal RT. It supplies to each selection part.

  That is, in the present embodiment, the control signal receiving unit 260 includes the clock signal Sck restored from the original control signal, the print data signal SI, the latch signal LAT, and the control signals c1, c2, c3, and c4. A plurality of types of parallel signals including the change signal CH and a switching period designation signal RT provided to the selection unit 230 are output. Details of the clock signal Sck, the print data signal SI, the latch signal LAT, the change signal CH, and the switching period designation signal RT will be described later.

The selection control unit 210-1 determines whether the drive signal COMA1 should be selected or not selected for each of the selection units 230, the clock signal Sck, the print data signal SI, the latch signal LAT, and the control signal c1. Instructed by a change signal CH.

  Each of the selection units 230 that receive the output signal of the selection control unit 210-1 selects the drive signal COMA1 in accordance with an instruction from the selection control unit 210-1, and drives each one end of the piezoelectric element 60 included in the head 20-1. Supply as a signal. In FIG. 5, the voltage of this drive signal is expressed as drive voltage Vout. The drive signal COMB1 is a signal for inspecting each ejection failure of the ejection unit 600. A common voltage VBS, which is a reference voltage, is commonly applied to the other end different from the one to which the drive voltage Vout of the piezoelectric element 60 is applied.

  In addition, each of the selection units 230 generates a selection signal Sw based on the switching period designation signal RT output from the control signal reception unit 260 and outputs the selection signal Sw to the switching unit 250. In the present embodiment, the selection signal Sw is a signal that is at a high level only when the switching period designation signal RT is at a high level and the drive signal COMB1 is selected.

  When the selection signal Sw output from the selection unit 230 is at a low level, the switching unit 250 applies the drive voltage Vout to one end of the piezoelectric element 60 included in the corresponding ejection unit 600 included in the head 20-1. When the selection signal Sw is at a high level, control is performed so that the drive voltage Vout is not applied to one end of the piezoelectric element 60. The piezoelectric element 60 is displaced when a drive signal is applied. The piezoelectric element 60 is provided corresponding to each of the plurality of ejection units 600 in the head 20-1. Then, the piezoelectric element 60 is displaced according to the potential difference between the drive voltage Vout and the common voltage VBS to eject ink.

  In the present embodiment, the switching period designation signal RT is always at the low level during the printing period, and the low level and the high level are periodically repeated during the inspection period. That is, the drive voltage Vout is always applied to all the ejection units 600 during the printing period. In the inspection period, the drive voltage Vout is always applied to the ejection unit 600 that is not subject to inspection (the ejection unit 600 corresponding to the selection unit 230 that does not select the drive signal COMB1 as the drive voltage Vout). After the drive voltage Vout is applied to the unit 600 (the ejection unit 600 corresponding to the selection unit 230 that selects the drive signal COMB1 as the drive voltage Vout), the drive voltage Vout is not applied for a certain period, A signal appearing at one end of the piezoelectric element 60 included in the ejection unit 600 is output from the switching unit 250 as a residual vibration signal Vrb-1.

  The amplification output unit 240 generates a residual vibration signal Vrbg-1 obtained by amplifying the residual vibration signal Vrb-1 indicating the state of the head unit 32, and outputs the residual vibration signal Vrbg-1 to the state signal determination unit 120.

  In the selection control unit 210-2, the control signal supplied from the control signal receiving unit 260 is the control signal c2 and the drive signals are the drive signals COMA2 and COMB2 with respect to the description of the selection control unit 210-1. That is, the head to be driven is the head 20-2, the signal output from the switching unit 250 to the amplification output unit 240 is the residual vibration signal Vrb-2, and the output of the amplification output unit 240 is the residual vibration signal Vrbg−. Since it is the same as that of the selection control part 210-1, except being 2, detailed description is abbreviate | omitted.

  In the selection control unit 210-3, the control signal supplied from the control signal receiving unit 260 is the control signal c3, and the drive signals are the drive signals COMA3 and COMB3 with respect to the description of the selection control unit 210-1. That is, the head to be driven is the head 20-3, the signal output from the switching unit 250 to the amplification output unit 240 is the residual vibration signal Vrb-3, and the output of the amplification output unit 240 is the residual vibration signal Vrbg−. Since it is the same as that of the selection control part 210-1, except that it is 3, detailed description is abbreviate | omitted.

  In the selection control unit 210-4, the control signal supplied from the control signal receiving unit 260 is the control signal c4, and the drive signals are the drive signals COMA4 and COMB4 with respect to the description of the selection control unit 210-1. That is, the head to be driven is the head 20-4, the signal output from the switching unit 250 to the amplification output unit 240 is the residual vibration signal Vrb-4, and the output of the amplification output unit 240 is the residual vibration signal Vrbg−. Since it is the same as that of the selection control part 210-1, except being 4, it abbreviate | omits detailed description.

  Thus, the residual vibration signal Vrbg input to the state signal determination unit 120 is a signal including the residual vibration signals Vrbg-1, Vrbg-2, Vrbg-3, and Vrbg-4.

  As described above, in the present embodiment, the selection control units 210-1, 210-2, 210-3, and 210-4 differ only in the control signals that are supplied and the selection units that are operated in accordance with the control signals. It has the same configuration. For this reason, when it is not necessary to particularly distinguish the selection control units 210-1, 210-2, 210-3, and 210-4, "-(hyphen)" and the following are omitted, and the symbol is simply "selection control unit". 210 ”.

  In the present embodiment, the heads 20-1, 20-2, 20-3, and 20-4 have the same configuration except that the supplied drive signals are different. For this reason, when it is not necessary to particularly distinguish the heads 20-1, 20-2, 20-3, and 20-4, “-(hyphen)” and the following are omitted, and the description is simply given as “head 20”. To do.

  In the present embodiment, the drive signals COMA1, COMB1, COMA2, COMB2, COMA3, COMB3, COMA4, and COMB4 have the same configuration except that the waveforms of the drive signals are different. Therefore, when it is not necessary to distinguish between them, the drive signals COMA1, COMA2, COMA3, and COMA4 are simply referred to as drive signals COMA, and the drive signals COMB1, COMB2, COMB3, and COMB4 are simply referred to as drive signals COMB. The drive signal COMA and the drive signal COMB are drive signals output to the same head 20 according to the selection unit 230.

  In the present embodiment, the residual vibration signals Vrb-1, Vrb-2, Vrb-3, and Vrb-4 have the same configuration except for the heads from which the residual detection signals are detected. For this reason, unless it is particularly necessary to distinguish, “− (hyphen)” and the following are omitted, and the code is simply referred to as “residual vibration signal Vrb”.

1.3 Configuration of Discharge Unit FIG. 6 is a diagram illustrating a schematic configuration corresponding to one discharge unit 600 in the head 20. As shown in FIG. 6, the head 20 includes a discharge unit 600 and a reservoir 641.

  The reservoir 641 is provided for each ink color, and the ink is introduced into the reservoir 641 from the supply port 661. The ink is supplied from the liquid storage means 4 mounted on the apparatus main body 7 to the supply port 661 through the supply pipe 8.

The discharge unit 600 includes a piezoelectric element 60, a vibration plate 621, a cavity (pressure chamber) 631, and a nozzle 651. Among them, the vibration plate 621 functions as a diaphragm that is displaced (bending vibration) by the piezoelectric element 60 provided on the upper surface in FIG. 6 and expands / reduces the internal volume of the cavity 631 filled with ink. The nozzle 651 is an opening provided in the nozzle plate 632 and communicating with the cavity 631. The cavity 631 is filled with a liquid (for example, ink), and the internal volume changes due to the displacement of the piezoelectric element 60. The nozzle 651 communicates with the cavity 631 and discharges the liquid in the cavity 631 as droplets according to the change in the internal volume of the cavity 631.

  The piezoelectric element 60 shown in FIG. 6 has a structure in which a piezoelectric body 601 is sandwiched between a pair of electrodes 611 and 612. In the piezoelectric body 601 having this structure, the central portion in FIG. 6 bends in the vertical direction with respect to both end portions together with the electrodes 611 and 612 and the diaphragm 621 in accordance with the voltage applied by the electrodes 611 and 612. Specifically, the piezoelectric element 60 is configured to bend upward when the voltage of the drive voltage Vout increases, and to bend downward when the voltage of the drive voltage Vout decreases. In this configuration, if the ink is bent upward, the internal volume of the cavity 631 is expanded. Therefore, if the ink is drawn from the reservoir 641, if the ink is bent downward, the internal volume of the cavity 631 is reduced. Depending on the degree, the ink is ejected from the nozzle 651.

  The piezoelectric element 60 is not limited to the illustrated structure, and may be any type that can deform the piezoelectric element 60 and discharge a liquid such as ink. Further, the piezoelectric element 60 is not limited to bending vibration, and may be configured to use so-called longitudinal vibration.

  In addition, the piezoelectric element 60 is provided corresponding to the cavity 631 and the nozzle 651 in the head 20, and is also provided corresponding to the selection unit 230. For this reason, a set of the piezoelectric element 60, the cavity 631, the nozzle 651, and the selection unit 230 is provided for each nozzle 651.

1.4 Relationship Between Discharge Failure of Residue Unit and Residual Vibration By the way, even though the discharge unit 600 performs an operation for ejecting ink droplets, ink droplets are not ejected normally from the nozzles 651, that is, ejection Defects may occur. The causes of the ejection failure include (1) mixing of bubbles into the cavity 631, (2) thickening or fixing of the ink in the cavity 631 due to drying of the ink in the cavity 631, and the like. (3) Adherence of foreign matters such as paper dust near the outlet of the nozzle 651 can be mentioned.

  First, when bubbles are mixed in the cavity 631, it is considered that the total weight of the ink filling the cavity 631 is reduced and the inertance is reduced. Further, when bubbles are attached in the vicinity of the nozzle 651, it is considered that the diameter of the nozzle 651 is increased by the size of the diameter, and it is considered that the acoustic resistance is lowered. Therefore, when bubbles are mixed in the cavity 631 and a discharge failure occurs, the frequency of residual vibration is higher than that in the case where the discharge state is normal. In addition, the attenuation rate of the residual vibration amplitude decreases due to a decrease in acoustic resistance.

  Next, when the ink in the vicinity of the nozzle 651 is dried and fixed, the ink in the cavity 631 is confined within the cavity 631. In such a case, it is considered that the acoustic resistance increases. Therefore, when the ink in the vicinity of the nozzle 651 in the cavity 631 is fixed, the residual vibration frequency is extremely low and the residual vibration is overdamped as compared with the case where the ejection state is normal.

  Next, when foreign matter such as paper dust adheres to the vicinity of the outlet of the nozzle 651, the ink oozes out from the cavity 631 through the foreign matter such as paper dust, so that the inertance is considered to increase. In addition, it is considered that the acoustic resistance is increased by the fiber of the paper powder attached near the outlet of the nozzle 651. Therefore, when a foreign substance such as paper dust adheres near the outlet of the nozzle 651, the frequency of the residual vibration is lower than when the ejection state is normal.

From the above, the state signal determination unit 120 is configured to reduce the frequency and amplitude attenuation rate (
Based on the (decay time), it is possible to determine the presence or absence of ejection failure.

1.5 Structure of ejection unit drive signal As a method of forming dots on the recording sheet S, in addition to a method of ejecting ink droplets once to form one dot, ink droplets are ejected twice per unit period. A method (second method) for forming one dot by landing one or more ink droplets ejected in a unit period and combining the one or more landed ink droplets so that ejection is possible. There is a method (third method) for forming two or more dots without combining the above ink droplets.

  In the present embodiment, by the second method, “large dot”, “medium dot”, “small dot”, and “non-recording (no dot)” are performed by ejecting ink twice at most for one dot. 4 gradations are expressed.

  In order to express these four gradations, in this embodiment, the drive signal COMA has a first half pattern and a second half pattern in one period of dot formation. It is configured to select (or not select) whether or not to supply the drive signal COMA to the piezoelectric element 60 in the first half and the second half in one cycle according to the gradation to be expressed. Further, in the present embodiment, a drive signal COMB is also prepared in order to generate the drive voltage Vout corresponding to “inspection”.

  FIG. 7 is a diagram illustrating waveforms of the drive signals COMA and COMB. As shown in FIG. 7, the drive signal COMA includes a trapezoidal waveform Adp1 arranged in a period T1 from when the latch signal LAT rises to when the change signal CH rises, and the latch signal LAT after the change signal CH rises. It is a waveform that is continuous with the trapezoidal waveform Adp2 arranged in the period T2 until the rise. A period composed of the period T1 and the period T2 is defined as a period Ta, and new dots are formed on the recording sheet S every period Ta.

  In the present embodiment, the trapezoidal waveforms Adp1 and Adp2 are different from each other. Among these, the trapezoidal waveform Adp1 is a waveform for ejecting a predetermined amount, specifically, a medium amount of ink from the nozzle 651 corresponding to the piezoelectric element 60, respectively. The trapezoidal waveform Adp2 is different from the trapezoidal waveform Adp1. If the trapezoidal waveform Adp2 is supplied to one end of the piezoelectric element 60, the nozzle 651 corresponding to the piezoelectric element 60 is a waveform for ejecting an amount of ink smaller than the predetermined amount.

  The drive signal COMB has a waveform in which the trapezoidal waveform Bdp1 arranged in the period T1 and the waveform of the constant voltage Vc arranged in the period T2 are continuous. The trapezoidal waveform Bdp1 is a waveform for causing the ink in the vicinity of the opening portion of the nozzle 651 to vibrate to generate a desired residual vibration necessary for the inspection. Even if the trapezoidal waveform Bdp1 is supplied to one end of the piezoelectric element 60, ink is not ejected from the nozzle 651 corresponding to the piezoelectric element 60.

  The voltage at the start timing and the voltage at the end timing of the trapezoidal waveforms Adp1, Adp2, and Bdp1 are all the same as the voltage Vc. That is, the trapezoidal waveforms Adp1, Adp2, and Bdp1 are waveforms that start at the voltage Vc and end at the voltage Vc, respectively.

  FIG. 8 is a diagram illustrating waveforms of the drive voltage Vout corresponding to “large dot”, “medium dot”, “small dot”, “non-recording”, and “inspection” in the present embodiment.

As shown in FIG. 8, the drive voltage Vout corresponding to the “large dot” is a waveform obtained by continuing the trapezoidal waveform Adp1 of the drive signal COMA in the period T1 and the trapezoidal waveform Adp2 of the drive signal COMA in the period T2. ing. When the driving voltage Vout is supplied to one end of the piezoelectric element 60, a medium amount of ink is ejected from the nozzle 651 corresponding to the piezoelectric element 60 in the period T1, and the piezoelectric element 60 is discharged to the piezoelectric element 60 in the period T2. A small amount of ink is ejected from the corresponding nozzle 651. Therefore, in the period Ta, the respective inks land on the recording sheet S and coalesce to form large dots.

  The drive voltage Vout corresponding to the “medium dot” is a waveform in which the trapezoidal waveform Adp1 of the drive signal COMA in the period T1 and the voltage Vc immediately before held by the capacitance of the piezoelectric element 60 in the period T2 are continuous. It has become. When this drive voltage Vout is supplied to one end of the piezoelectric element 60, a medium amount of ink is ejected once from the nozzle 651 corresponding to the piezoelectric element 60 in the period Ta. For this reason, medium dots are formed on the recording sheet S in the cycle Ta.

  The drive voltage Vout corresponding to the “small dot” is a waveform obtained by continuing the voltage Vc immediately before being held by the capacitive property of the piezoelectric element 60 in the period T1 and the trapezoidal waveform Adp2 of the drive signal COMA in the period T2. It has become. When this drive voltage Vout is supplied to one end of the piezoelectric element 60, a small amount of ink is ejected once from the nozzle 651 corresponding to the piezoelectric element 60 in the period Ta. For this reason, small dots are formed on the recording sheet S in the cycle Ta.

  The drive voltage Vout corresponding to “non-recording” has a waveform in which the voltage Vc immediately before held by the capacitive property of the piezoelectric element 60 is continued in the period T1 and the period T2. That is, in the period Ta, the piezoelectric element 60 is not driven and ink is not ejected. For this reason, no dots are formed on the recording sheet S.

  The drive voltage Vout corresponding to “inspection” is a trapezoidal waveform Bdp1 of the drive signal COMB in the period T1, and is the voltage Vc just before being held by the capacitance of the piezoelectric element 60 in the period T2. When the driving voltage Vout for inspection is supplied to one end of the piezoelectric element 60, the ejection unit 600 including the piezoelectric element 60 vibrates in the period T1 to generate residual vibration, but ink is not ejected. In the present embodiment, the drive voltage Vout corresponding to “non-recording” is applied to all ejection units 600 that are not inspection targets.

1.6 Configuration of Selection Control Unit and Selection Unit FIG. 9 is a diagram illustrating a configuration of the selection control unit 210 in FIG. As shown in FIG. 9, the selection control unit 210 includes a clock signal Sck, a print data signal SI, and a latch signal LAT included in each of the control signals c1, c2, c3, and c4 output from the control signal receiving unit 260. The change signal CH is supplied. In the selection control unit 210, a set of a shift register (S / R) 212, a latch circuit 214, and a decoder 216 is provided corresponding to each of the piezoelectric elements 60 (nozzles 651).

  The print data signal SI is 3 for selecting any one of “large dot”, “medium dot”, “small dot”, “non-recording” and “inspection” for each of the m ejection portions 600. It is a signal of 3 m bits in total including bit print data (SIH, SIM, SIL).

  The print data signal SI is serially supplied from the control signal receiving unit 260 in synchronization with the clock signal Sck. The shift register 212 is configured to once hold the serially supplied print data signal SI for each of the 3-bit print data (SIH, SIM, SIL) corresponding to each nozzle 651.

Specifically, the shift registers 212 having the number of stages corresponding to the piezoelectric elements 60 (nozzles) are cascade-connected to each other, and the print data signal SI supplied serially is the clock signal S.
According to ck, the data is sequentially transferred to the subsequent stage.

  When the number of piezoelectric elements 60 is m (m is a plurality), in order to distinguish the shift register 212, the first, second,..., M in order from the upstream side to which the print data signal SI is supplied. It is written as a step.

  Each of the m latch circuits 214 latches 3-bit print data (SIH, SIM, SIL) held in each of the m shift registers 212 at the rising edge of the latch signal LAT.

  Each of the m decoders 216 decodes 3-bit print data (SIH, SIM, SIL) latched by each of the m latch circuits 214, and is defined by a latch signal LAT and a change signal CH. The selection signals Sa and Sb are output for each of the periods T1 and T2 to define the selection by the selection unit 230.

  FIG. 10 is a diagram showing the decoding contents in the decoder 216. For example, if the latched 3-bit print data (SIH, SIM, SIL) is (1, 0, 0), the decoder 216 sets the logic levels of the selection signals Sa and Sb to the H and L levels in the period T1, respectively. In the period T2, it means to output as L and L levels, respectively.

  Note that the logic levels of the selection signals Sa and Sb are shifted to higher amplitude logic by a level shifter (not shown) than the logic levels of the clock signal Sck, the print data signal SI, the latch signal LAT, and the change signal CH. The

  FIG. 11 is a diagram illustrating a configuration of the selection unit 230 corresponding to one piezoelectric element 60 (nozzle 651) in FIG.

  As illustrated in FIG. 11, the selection unit 230 includes inverters (NOT circuits) 232a and 232b, transfer gates 234a and 234b, and an AND circuit 236.

  The selection signal Sa from the decoder 216 is supplied to the positive control terminal that is not circled in the transfer gate 234a, while being logically inverted by the inverter 232a and negative control that is circled in the transfer gate 234a. Supplied to the end. Similarly, the selection signal Sb is supplied to the positive control terminal of the transfer gate 234b, while logically inverted by the inverter 232b and supplied to the negative control terminal of the transfer gate 234b.

  The drive signal COMA is supplied to the input terminal of the transfer gate 234a, and the drive signal COMB is supplied to the input terminal of the transfer gate 234b. The output terminals of the transfer gates 234a and 234b are connected in common, and the drive voltage Vout is output to the switching unit 250 via the common connection terminal.

  When the selection signal Sa is at the H level, the transfer gate 234a conducts (turns on) between the input end and the output end, and when the selection signal Sa is at the L level, the transfer gate 234a does not conduct between the input end and the output end. (Off). Similarly, the transfer gate 234b is turned on / off between the input end and the output end according to the selection signal Sb.

  The AND circuit 236 outputs a signal representing the logical product of the selection signal Sb and the switching period designation signal RT to the switching unit 250 as the selection signal Sw.

  Next, operations of the selection control unit 210 and the selection unit 230 will be described with reference to FIG.

  The print data signal SI is serially supplied from the control signal receiving unit 260 in synchronization with the clock signal Sck, and sequentially transferred in the shift register 212 corresponding to each nozzle. When the control signal receiving unit 260 stops the supply of the clock signal Sck, each shift register 212 is in a state where 3-bit print data (SIH, SIM, SIL) corresponding to the nozzle is held. The print data signal SI is supplied in the order corresponding to the last m stages,..., Two stages, and one stage nozzles in the shift register 212.

  Here, when the latch signal LAT rises, each of the latch circuits 214 simultaneously latches 3-bit print data (SIH, SIM, SIL) held in the shift register 212. In FIG. 12, LT1, LT2,..., LTm are 3-bit print data (SIH, SIM, SIL) latched by the latch circuit 214 corresponding to the 1-stage, 2-stage,. Show.

  The decoder 216 sets the logic levels of the selection signals Sa and Sb in FIG. 10 in each of the periods T1 and T2 according to the dot size defined by the latched 3-bit print data (SIH, SIM, SIL). Output as shown.

  That is, when the print data (SIH, SIM, SIL) is (1, 1, 0) and the size of the large dot is defined, the decoder 216 sends the selection signals Sa, Sb to H, L in the period T1. Level, and the H and L levels in the period T2. In addition, when the print data (SIH, SIM, SIL) is (1, 0, 0) and the size of the medium dot is defined, the decoder 216 sends the selection signals Sa and Sb to H, L in the period T1. Level, and the L and L levels in the period T2. Further, when the print data (SIH, SIM, SIL) is (0, 1, 0) and the size of the small dot is defined, the decoder 216 sends the selection signals Sa and Sb to L, L in the period T1. Level, and H and L levels in the period T2. Further, when the print data (SIH, SIM, SIL) is (0, 0, 0) and the non-recording is specified, the decoder 216 sets the selection signals Sa and Sb to the L and L levels in the period T1. In the period T2, the L and L levels are set. Further, when the print data (SIH, SIM, SIL) is (0, 0, 1) and the inspection is defined, the decoder 216 sets the selection signals Sa and Sb to the L and H levels in the period T1, The L and H levels are also set during the period T2.

  When the print data (SIH, SIM, SIL) is (1, 1, 0), the selection unit 230 receives the drive signal COMA (trapezoidal waveform Adp1) because the selection signals Sa and Sb are at the H and L levels in the period T1. In the period T2, since the Sa and Sb are at the H and L levels, the drive signal COMA (trapezoidal waveform Adp2) is selected. As a result, the drive voltage Vout corresponding to the “large dot” shown in FIG. 8 is generated.

  In addition, when the print data (SIH, SIM, SIL) is (1, 0, 0), the selection unit 230 selects the drive signal COMA (trapezoidal waveform Adp1) because the selection signals Sa and Sb are at the H and L levels in the period T1. In the period T2, since Sa and Sb are at the L and L levels, neither of the drive signals COMA and COMB is selected. As a result, the drive voltage Vout corresponding to the “medium dot” shown in FIG. 8 is generated.

In addition, when the print data (SIH, SIM, SIL) is (0, 1, 0), the selection unit 230 determines which of the drive signals COMA, COMB since the selection signals Sa, Sb are L and L levels in the period T1. In the period T2, Sa and Sb are at the H and L levels, so the drive signal COMB (trapezoidal waveform Adp2) is selected. As a result, the drive voltage Vout corresponding to the “small dot” shown in FIG. 8 is generated.

  In addition, when the print data (SIH, SIM, SIL) is (0, 0, 0), the selection unit 230 determines which of the drive signals COMA and COMB since the selection signals Sa and Sb are at the L and L levels in the period T1. In the period T2, since the selection signals Sa and Sb are at the L and L levels, neither of the drive signals COMA and COMB is selected. As a result, the drive voltage Vout corresponding to “non-recording” shown in FIG. 8 is generated.

  In addition, when the print data (SIH, SIM, SIL) is (0, 0, 1), the selection unit 230 selects the drive signals COMB (trapezoidal waveform Bdp1) because the selection signals Sa and Sb are at the L and H levels in the period T1. ) And Sa and Sb are at the L and H levels even during the period T2, and the drive signal COMB (constant voltage Vc) is selected. As a result, the drive voltage Vout corresponding to the “inspection” shown in FIG. 8 is generated.

  Note that, during the period in which the selection signals Sa and Sb are at the L and L levels, neither of the drive signals COMA and COMB is selected, so that one end of the piezoelectric element 60 is open. However, the drive voltage Vout is held at the immediately preceding voltage Vc due to the capacitance of the piezoelectric element 60.

  Note that the drive signals COMA and COMB shown in FIGS. 7 and 12 are merely examples. Actually, various combinations of waveforms prepared in advance are used according to the moving speed of the head unit 32 and the properties of the print medium.

  Further, here, the example in which the piezoelectric element 60 bends upward as the voltage increases has been described. However, when the voltage supplied to the electrodes 611 and 612 is reversed, the piezoelectric element 60 increases as the voltage increases. Will bend downward. For this reason, in the configuration in which the piezoelectric element 60 bends downward as the voltage increases, the drive signals COMA and COMB illustrated in FIGS. 7 and 12 have waveforms that are inverted with respect to the voltage Vc.

1.7 Configuration of Switching Unit FIG. 13 is a diagram illustrating a configuration of the switching unit 250. As illustrated in FIG. 13, the switching unit 250 includes m switches 252-1 to 252-m connected to one end of the piezoelectric element 60 included in each of the m ejection units 600, and the m switches 252. −1 to 252-m are controlled by m selection signals Sw (Sw-1 to Sw-m) output from the m selection units 230, respectively.

  Specifically, the switch 252-i (i is any one of 1 to m) is one end of the piezoelectric element 60 that the i-th ejection unit 600 has the drive voltage Vout-i when Sw-i is at a low level. Apply to. In addition, when the switch Sw-i is at a high level, the switch 252-i does not apply the drive voltage Vout-i to one end of the piezoelectric element 60 included in the i-th ejection unit 600, and is generated at one end of the piezoelectric element 60. Is selected as the residual vibration signal Vrb. In the printing period, the switching period designation signal RT is at a low level, and the m selection signals Sw (Sw-1 to Sw-m) are all at a low level. ”,“ Medium dot ”,“ small dot ”, and“ non-recording ”, the driving voltage Vout (Vout-1 to Vout-m) is supplied. In the inspection period, when the selection signal Sw-i is low level (the switching period designation signal RT is low level), the i-th (i is any one of 1 to m) ejection unit 600 to be inspected. When the drive voltage Vout-i corresponding to “inspection” is supplied and the selection signal Sw-i is at the high level (the switching period designation signal RT is at the high level), the signal from the i-th ejection unit 600 is the residual vibration signal. It is output from the switching unit 250 as Vrb. In the inspection period, the other selection signals Sw-j (j is any one of 1 to m except i) are at a low level, and the ejection unit 600 to be inspected is driven corresponding to “non-recording”. A signal is supplied.

  That is, in the present embodiment, the switching period designation signal RT is commonly supplied to all the selection units 230. For example, when a drive signal corresponding to “inspection” is supplied to the piezoelectric element 60 included in any one of the ejection units 600 of the head 20-1, other elements that do not correspond to “inspection” included in the head 20-1. The ejection unit 600 and all the ejection units 600 included in the heads 20-2, 20-3, and 20-4 are supplied with a drive signal corresponding to “non-recording”.

  At this time, only the residual vibration signal Vrb-1 of the piezoelectric element 60 included in any one of the ejection units 600 of the head 20-1 corresponding to “inspection” is determined as the residual vibration signal Vrbg via the amplification output unit 240. Is transmitted to the unit 120. Similarly, the ejection units 600 included in any of the heads 20-1, 20-2, 20-3, 20-4 are sequentially subjected to “inspection” in accordance with the switching period designation signal RT. That is, according to the switching period designation signal RT, the piezoelectric element 60 included in any one of the ejection units 600 of the heads 20-1, 20-2, 20-3, and 20-4 is subjected to “inspection” in a time-sharing manner. The residual vibration signals Vrbg obtained by amplifying the residual vibration signals Vrb are transmitted to the state signal determination unit 120 in a time division manner.

  FIG. 14 shows an example of waveforms of the switching period designation signal RT, the drive voltage Vout applied to the ejection unit 600 to be inspected, and the residual vibration signal Vrb in the inspection period. FIG. 14 also shows the waveform of the residual vibration signal Vrbg output from the amplification output unit 240 (see FIG. 5). As shown in FIG. 14, when the switching period designation signal RT is at a low level, the drive voltage Vout (inspection drive signal COMB) is applied to the ejection unit 600 to be inspected. Further, when the switching period designation signal RT is at a high level, the drive voltage Vout is not applied to the ejection unit 600 to be inspected, and the waveform due to the residual vibration after the drive voltage Vout is applied to the ejection unit 600 is a residual vibration signal. Appears at Vrb. The residual vibration signal Vrb is amplified by the amplification output unit 240 to become a residual vibration signal Vrbg, and this residual vibration signal Vrbg is transmitted to the state signal determination unit 120 provided in the control unit 10. That is, the residual vibration signal Vrbg in the present embodiment is an analog signal in which a waveform due to residual vibration after the drive voltage Vout is applied to the ejection unit 600 is amplified.

1.8 Configuration of Head Unit FIG. 15 is an exploded perspective view showing the configuration of the head unit 32. Note that the three axes (X, Y, Z) illustrated in FIG. 15 correspond to the “first direction X”, “second direction Y”, and “third direction Z” illustrated in FIGS. "Indicates the same direction.

  The head unit 32 includes a head main body 310 that ejects ink as a liquid, and a flow path member 370 that is fixed to the head main body 310.

  The head main body 310 includes a plurality of drive units 320 having the head 20, a holder 330 that holds the plurality of drive units 320, a relay board 340 fixed to the holder 330, a supply member 350, and a plurality of drive units 320. A fixing plate 360 to be fixed.

  The drive unit 320 includes the head 20, and as shown in FIG. 3, a plurality of rows in which nozzles 651 for ejecting ink are arranged in parallel in the first direction X, and in this embodiment, two rows are provided. Yes. On the surface opposite to the surface in which the nozzle 651 of each drive unit 320 is provided in the third direction Z, a drive wiring 322 connected to an interposer substrate (not shown) provided in the drive unit 320 is provided. Has been derived. The head 20 is electrically connected to the drive wiring 322 through an interposer substrate or the like inside the drive unit 320.

The holder 330 is provided with a housing (not shown) that houses the plurality of drive units 320 on the side where the fixing plate 360 in the third direction Z is provided. The accommodating portion has a concave shape that opens to the side where the fixing plate 360 in the third direction Z is provided, accommodates a plurality of drive units 320 fixed by the fixing plate 360, and the opening of the accommodating portion is fixed. Sealed by a plate 360. That is, the drive unit 320 is accommodated in the space formed by the accommodating portion and the fixed plate 360.

  The holder 330 is provided with a communication channel 332 for supplying ink supplied from the supply member 350 to the drive unit 320. Two communication flow paths 332 are provided for one drive unit 320. That is, the communication flow path 332 is provided corresponding to each row of the nozzles 651 provided in one drive unit 320.

  Further, the holder 330 is provided with a drive wiring 322 electrically connected to the drive unit 320 provided in the housing portion on the surface where the housing portion in the third direction Z is provided and on the third direction Z side. A wiring insertion hole 333 is provided for insertion through different surfaces. The drive wiring 322 is led out from the space formed by the housing portion and the fixing plate 360 by being inserted into the wiring insertion hole 333 of the holder 330.

  A relay substrate 340 is held on the side of the holder 330 from which the drive wiring 322 is derived. The relay board 340 has a drive wiring connection hole 341 penetrating in the third direction Z which is the thickness direction, and the drive wiring 322 is inserted through the drive wiring connection hole 341 of the relay board 340 and is connected to the relay board 340. Electrically connected.

  In addition, the relay substrate 340 is provided with an insertion hole 342 at a position corresponding to the communication channel 332 of the holder 330. The insertion hole 342 inserts a protrusion (not shown) provided in the supply member 350. The protrusions supply ink from the supply member 350 to the holder 330 by connecting the supply member 350 and the communication flow path 332 of the holder 330.

  Further, a control signal connector 280 and a drive signal connector 290 are provided on both sides of the relay board 340 in the second direction Y, respectively. The relay board 340 is electrically connected to the control unit 10 via flexible flat cables 190 and 191 (see FIG. 4).

  The supply member 350 is fixed to the holder 330 on the third direction Z side. In addition, the supply member 350 is provided with a supply channel 352 for supplying the ink supplied from the channel member 370 to the communication channel 332 of the holder 330. The supply channel 352 is provided to be open on both surfaces of the supply member 350 in the third direction Z. The supply flow path 352 has a first direction X or a second direction Y depending on the position of the flow path of the flow path member 370 and the insertion hole 342 of the relay substrate 340 and the communication flow path 332 of the holder 330. It may have a flow path extending in the direction.

  Further, the supply member 350 is provided with through holes 353 penetrating in the third direction Z at positions corresponding to the control signal connector 280 and the drive signal connector 290, respectively. That is, the flexible flat cables 190 and 191 (see FIG. 4) are inserted through the through hole 353 of the supply member 350 and connected to the control signal connector 280 and the drive signal connector 290.

In addition, the fixing plate 360 that closes the opening of the accommodating portion of the holder 330 is provided with an exposed opening 361 that exposes the nozzle 651 of each drive unit 320. In the present embodiment, the exposure opening 361 is provided independently for each drive unit 320, and a space between adjacent drive units 320 is sealed by a fixing plate 360. Note that the fixing plate 360 is fixed to the drive unit 320 at the peripheral edge of the exposure opening 361.

  The flow path member 370 is fixed to the supply member 350 side of the head main body 310 in the third direction Z side. The flow path member 370 is configured by stacking a plurality of filter units 390 in the second direction Y. Further, the filter unit 390 is provided with a plurality of flow path members 395 inside, removes bubbles and foreign matters contained in the ink, and supplies the ink to the supply member 350 provided in the head main body 310.

  The head unit 32 in this embodiment supplies the ink supplied from the flow path member 370 to the drive unit 320 via the supply flow path 352 and the communication flow path 332 provided in the head main body 310. Then, an ink droplet is ejected (or inspected) from the nozzle 651 by driving the piezoelectric element 60 in the head 20 provided in the drive unit 320 based on the drive signals COMA and COMB.

1.9 Configuration of Relay Board FIGS. 16 to 21 are diagrams showing the configuration of the relay board 340 in the present embodiment.

  FIG. 16 is a plan view of the relay substrate 340 as viewed from the first wiring layer 471, and is a diagram illustrating the configuration of the first wiring layer 471 of the relay substrate 340. FIG. 17 is a plan perspective view of the relay substrate 340 as viewed from the first wiring layer 471, and is a diagram illustrating the configuration of the second wiring layer 472 of the relay substrate 340. FIG. 18 is a plan perspective view of the relay substrate 340 as viewed from the first wiring layer 471, and is a diagram showing the configuration of the third wiring layer 473 of the relay substrate 340. FIG. 19 is a plan perspective view of the relay substrate 340 as viewed from the first wiring layer 471, and is a diagram showing the configuration of the fourth wiring layer 474 of the relay substrate 340. FIG. 20 is a plan perspective view of the relay substrate 340 as viewed from the first wiring layer 471 and shows the configuration of the fifth wiring layer 475 of the relay substrate 340. FIG. 21 is a plan perspective view of the relay substrate 340 as viewed from the first wiring layer 471, and is a diagram illustrating the configuration of the sixth wiring layer 476 of the relay substrate 340. FIG.

  The relay substrate 340 of the present embodiment includes a first wiring layer 471 (in this embodiment, the surface of the substrate 470), a second wiring layer 472, and a third wiring layer 473 shown in FIGS. The fourth wiring layer 474, the fifth wiring layer 475, and the sixth wiring layer 476 (in this embodiment, the back surface of the substrate 470) are stacked in this order. Note that the substrate 470 may include a wiring layer other than the wiring layer.

  The planar shape of the substrate 470 (an example of “circuit board”) is a substantially rectangular shape including a pair of short sides 481 and 482 and a pair of long sides 483 and 484. 16 to FIG. 21, the direction from the short side 481 to the short side 482, that is, the direction substantially parallel to the long side 483 is “long side direction x”, the direction from the long side 483 to the long side 484, That is, description will be made assuming that the direction substantially parallel to the short side 481 is the “short side direction y”.

  Further, as described above, the drive wiring connection hole 341 for inserting the drive wiring 322 electrically connected to the drive unit 320 and the communication channel 332 of the supply member 350 and the holder 330 are connected to the substrate 470. Thus, an insertion hole 342 for inserting a discharge unit that supplies ink from the supply member 350 to the holder 330 is provided.

1.9.1 Configuration of First Wiring Layer As shown in FIG. 16, the first wiring layer 471 of the relay board 340 includes a control signal receiver 260, a control signal connector 280, a drive signal connector 290, and an input. Output electrodes 451, 452, 453, and 454. Further, the first wiring layer 471 includes a plurality of wirings connecting the above-described configuration, a plurality of vias for connecting to another wiring layer of the substrate 470,
including.

  The control signal connector 280 includes a plurality of electrodes including control electrodes 401, 402, 403, 404, 405, and 406 arranged side by side along the long side direction x, and is provided on the long side 483 side of the substrate 470. Specifically, the control signal connector 280 is provided in a row in the order of the control electrodes 401, 402, 403, 404, 405, 406 from the short side 481 side along the long side direction x. Each of these electrodes may include two or more electrodes.

  The control signal connector 280 is connected to the control unit 10 via a flexible flat cable 191 as shown in FIG. The control signal connector 280 inputs the differential signals d1, d2, d3, and d4 from the control signal transmission unit 110 provided in the control unit 10 to the relay board 340, and the residual vibration signal Vrbg detected by the ejection unit 600. Is output to the state signal determination unit 120.

  The control electrode 401 is connected to the control wiring 411. The control electrode 401 receives, for example, a differential signal d1 input to the control signal connector 280 via the flexible flat cable 191 and outputs it to the control wiring 411. As described above, in the present embodiment, the differential signal d1 is a pair of differential signals. Therefore, the control wiring 411 in the present embodiment includes at least two wirings for transferring the signal. Similarly, the control electrode 401 includes at least two electrodes for inputting and outputting the signal.

  The control electrode 402 is connected to the control wiring 412. The control electrode 402 receives, for example, a differential signal d2 input to the control signal connector 280 via the flexible flat cable 191 and outputs it to the control wiring 412. As described above, in the present embodiment, the differential signal d2 is a pair of differential signals. Therefore, the control wiring 412 in this embodiment includes at least two wirings for transferring the signal. Similarly, the control electrode 402 includes at least two electrodes for inputting and outputting the signal.

  The control electrode 403 is connected to the control wiring 413. The control electrode 403 receives, for example, a differential signal d3 input to the control signal connector 280 via the flexible flat cable 191 and outputs it to the control wiring 413. As described above, in the present embodiment, the differential signal d3 is a pair of differential signals. For this reason, the control wiring 413 in this embodiment includes at least two wirings for transferring the signal. Similarly, the control electrode 403 includes at least two electrodes for inputting and outputting the signal.

  The control electrode 404 is connected to the control wiring 414. The control electrode 404 receives, for example, a differential signal d4 input to the control signal connector 280 via the flexible flat cable 191 and outputs it to the control wiring 414. As described above, in the present embodiment, the differential signal d4 is a pair of differential signals. Therefore, the control wiring 414 in this embodiment includes at least two wirings for transferring the signal. Similarly, the control electrode 404 includes at least two electrodes for inputting and outputting the signal.

  The control electrode 405 (an example of “first output terminal”) is connected to the residual vibration signal wiring 415. The control electrode 405 outputs the residual vibration signal Vrbg detected by the discharge unit 600 to the state signal determination unit via the flexible flat cable 191.

  Here, the residual vibration signal wiring 415 (an example of “first wiring”) is a wiring that is electrically connected in common with input / output electrodes 451, 452, 453, and 454 described later, and transfers the residual vibration signal Vrbg. .

  Here, as described above, the residual vibration signal Vrbg in the present embodiment is, for example, the piezoelectric element 60 (“first piezoelectric”) included in the ejection unit 600 (an example of “first ejection unit”) provided in the head 20-1. Residual vibration indicating residual vibration (an example of “first residual vibration”) that occurs after the drive signal COMB1 (an example of “first drive signal”) is supplied to and driven by the drive signal COMB1. The signal Vrb-1 is a signal including the residual vibration signal Vrbg-1 (an example of “first residual vibration signal”) amplified by the amplification output unit 240.

  In the present embodiment, the piezoelectric elements 60 included in the ejection unit 600 of the head 20 of each drive unit 320 are sequentially inspected according to the switching period designation signal RT, and the residual vibration signal Vrbg is a state signal in a time-sharing manner for each piezoelectric element 60. It is transferred to the determination unit 120. For example, the residual vibration signal Vrb-1 generated after the piezoelectric element 60 (an example of the “first piezoelectric element”) included in the ejection unit 600 (an example of the “first ejection unit”) of the head 20-1 is driven is amplified. Residual vibration signal Vrbg-1 (an example of “first residual vibration signal”) and a piezoelectric element 60 (“second piezoelectric element” included in the ejection unit 600 (an example of “second ejection unit”) of the head 20-2. "An example)" is a residual vibration signal Vrbg-2 (an example of "second residual vibration signal") obtained by amplifying the residual vibration signal Vrb-2 generated after the It is transferred to the signal determination unit 120.

  Thereby, wiring for individually transferring the residual vibration signal Vrb to the plurality of piezoelectric elements 60 is not necessary, and the relay substrate 340 can be downsized. In this embodiment, four drive units 320 are transferred in a time division manner using one residual vibration signal wiring 415. However, four or more drive units 320 may be transferred in a time division manner using one wiring. . Further, for example, a configuration may be adopted in which two drive units 320 are transferred in a time-sharing manner using one wiring and two such wirings are provided.

  In addition, input / output electrodes 451 (an example of “first input terminal”), 452, 453, and 454 to which the residual vibration signal Vrbg is input, a control signal connector 280 that outputs to the state signal determination unit 120, and a residual vibration signal The residual vibration signal wiring 415 to which Vrbg is transferred is formed in the first wiring layer 471 (an example of “first layer”).

  Accordingly, the residual vibration signal wiring 415 does not need to be provided with a via or the like, and the residual vibration signal Vrbg detected by the ejection unit 600 can be transferred with high accuracy.

  Control electrode 406 is connected to via 426. A constant potential for matching the reference potentials of the relay substrate 340 and the control unit 10 is input to the control electrode 406. Then, it is electrically connected to the second wiring layer 472 (see FIG. 17) through the via 426.

  As described with reference to FIGS. 4 and 5, the control signal receiving unit 260 receives the differential signals d1, d2, d3, and d4 of the LVDS transfer method, converts and restores the control signals c1, c2, c3, and so on. c4 and the switching period designation signal RT are generated (restored) and output. In the present embodiment, the control signal receiving unit 260 may be configured by a one-chip IC (Integrated Circuit), or may be configured by a plurality of components.

  The control signal receiving unit 260 is connected to the control wirings 411, 412, 413, 414 and vias 421, 422, 423, 424.

The control wiring 411 transfers, for example, the differential signal d1 input to the control electrode 401, and inputs the differential signal to the control signal receiving unit 260. Further, a termination resistor 410 for stabilizing communication is provided in parallel with the control signal receiving unit 260 between the pair of control wirings 411. At this time, the control wiring 411 for transferring the differential signal d1, the control electrode 401 to which the differential signal d1 is input, and the control signal receiving unit 260 are provided in the first wiring layer 471. Further, the control wiring 411 is not provided with a via or the like, and is not connected to anything other than the termination resistor 410, the control electrode 401, and the control signal receiving unit 260.

  By wiring in this way, only the configuration necessary for stably transferring the differential signal d1 to the control signal receiving unit 260 is connected to the control wiring 411. Thereby, the control wiring 411 can be wired as short as possible, and stable transmission is realized.

  Similarly, the control wiring 412 transfers, for example, the differential signal d2 input to the control electrode 402, and inputs the differential signal to the control signal receiving unit 260. In addition, a termination resistor 410 for stabilizing communication is provided in parallel with the control signal receiving unit 260 between the pair of control wirings 412.

  Similarly, the control wiring 413 transfers, for example, the differential signal d3 input to the control electrode 403, and inputs the differential signal to the control signal receiving unit 260. Further, a termination resistor 410 for stabilizing communication is provided in parallel with the control signal receiving unit 260 between the pair of control wirings 413.

  Similarly, the control wiring 414 transfers, for example, the differential signal d4 input to the control electrode 404, and inputs the differential signal to the control signal receiving unit 260. In addition, a termination resistor 410 for stabilizing communication is provided in parallel with the control signal receiving unit 260 between the pair of control wires 414.

  Note that the termination resistor 410 is preferably provided in the vicinity of the control signal receiving unit 260. Thereby, reflection and interference of the transmission signal can be further reduced. Further, the termination resistor 410 is not limited to the parallel termination shown in FIG. 16, but may be a series termination, a Thevenin termination, an RC termination, or the like.

  The via 421 passes through the first wiring layer 471 and the third wiring layer 473 and is electrically connected to the control wiring 431 (see FIG. 18) provided in the third wiring layer 473. That is, the control signal receiving unit 260 is electrically connected to the control wiring 431 via the via 421.

  The via 422 passes through the first wiring layer 471 and the third wiring layer 473 and is electrically connected to the control wiring 432 (see FIG. 18) provided in the third wiring layer 473. That is, the control signal receiving unit 260 is electrically connected to the control wiring 432 through the via 422.

  The via 423 is electrically connected to the control wiring 433 (see FIG. 18) provided in the third wiring layer 473 through the first wiring layer 471 and the third wiring layer 473. That is, the control signal receiving unit 260 is electrically connected to the control wiring 433 via the via 423.

  The via 424 passes through the first wiring layer 471 and the third wiring layer 473 and is electrically connected to the control wiring 434 (see FIG. 18) provided in the third wiring layer 473. That is, the control signal receiving unit 260 is connected to the control wiring 434 via the via 424.

  That is, the control signal receiving unit 260 includes control wirings 411, 412, 413, and 414 for transferring the differential signals d1, d2, d3, and d4, control signals c1, c2, c3, and c4 based on the differential signals, and a switching period. It is connected to control wirings 431, 432, 433, 434 for transferring the designation signal RT.

Here, the control signals c1, c2, c3, and c4 are signals including the clock signal Sck, the print data signal SI, the latch signal LAT, and the change signal CH as described above. Therefore, each of the vias 421, 422, 423, and 424 needs to transfer at least five signals obtained by adding the switching period designation signal RT to the clock signal Sck, the print data signal SI, the latch signal LAT, and the change signal CH. The Thus, each of the vias 421, 422, 423, and 424 includes at least five vias.

  The drive signal connector 290 includes a plurality of electrodes including drive electrodes 501, 502, 503, 504, 505, 506, 507, 508, 509, 510, 511, 512 provided along the long side direction x, 470 is provided on the long side 484 side. Specifically, the control signal connector 280 is arranged in the order of the drive electrodes 501, 502, 503, 504, 505, 506, 507, 508, 509, 510, 511, 512 from the short side 481 side along the long side direction x. It is provided in a row. Note that these electrodes may include two or more electrodes.

  The drive signal connector 290 is connected to the control unit 10 via a flexible flat cable 190 as shown in FIG. Then, the drive signal connector 290 inputs the drive signals COMA and COMB output from the drive circuit 50 and the common voltage VBS to the relay board 340.

  The drive electrodes 501, 502, and 503 are supplied with drive signals COMA1 and COMB1, which are mounted on one drive unit 320 and drive the head 20, and a common voltage VBS. Specifically, a drive signal COMA1 is input to the drive electrode 501 and is output to the via 521 connected to the drive electrode 501. Further, the common voltage VBS is input to the drive electrode 502 and is output to the via 522 connected to the drive electrode 502. Further, the drive signal COMB 1 is input to the drive electrode 503 and is output to the via 523 connected to the drive electrode 503.

  Drive signals COMA2 and COMB2 mounted on one drive unit 320 and driving the head 20 and a common voltage VBS are input to the drive electrodes 504, 505, and 506. Specifically, the drive signal COMA 2 is input to the drive electrode 504 and is output to the via 524 connected to the drive electrode 504. A common voltage VBS is input to the drive electrode 505 and is output to the via 525 connected to the drive electrode 505. Further, the drive signal COMB 2 is input to the drive electrode 506 and is output to the via 526 connected to the drive electrode 506.

  Drive signals COMA3 and COMB3, which are mounted on one drive unit 320 and drive the head 20, and a common voltage VBS are input to the drive electrodes 507, 508, and 509. Specifically, the drive signal COMA 3 is input to the drive electrode 507 and is output to the via 527 connected to the drive electrode 507. Further, the common voltage VBS is input to the drive electrode 508 and is output to the via 528 connected to the drive electrode 508. Further, the drive signal COMB 3 is input to the drive electrode 509 and is output to the via 529 connected to the drive electrode 509.

  Driving signals COMA4 and COMB4 that are mounted on one driving unit 320 and drive the head 20 and a common voltage VBS are input to the driving electrodes 510, 511, and 512. Specifically, the drive signal 510 is input to the drive electrode 510 and is output to the via 530 connected to the drive electrode 510. A common voltage VBS is input to the drive electrode 511 and is output to the via 531 connected to the drive electrode 511. Further, the drive signal 512 is input to the drive electrode 512 and is output to the via 532 connected to the drive electrode 512.

  The input / output electrode 451 is connected to the vias 441, 541, 542, 543 and the residual vibration signal wiring 415.

The input / output electrode 452 is connected to the vias 442, 544, 545, 546 and the residual vibration signal wiring 415.

  The input / output electrode 453 is connected to the vias 443, 547, 548, 549 and the residual vibration signal wiring 415.

  The input / output electrode 454 is connected to the vias 444, 550, 551, 552 and the residual vibration signal wiring 415.

  According to the first wiring layer 471 of the relay substrate 340 in the present embodiment, the drive signal connector 290 to which the drive signals COMA and COMB and the common voltage VBS are input, the differential signals d1, d2, d3, d4, and the like. The input control signal connector 280 is constituted by a separate connector. Further, the drive signal connector 290 is provided on the long side 484 side of the substrate 470, and the control signal connector 280 is provided on the long side 483 side of the substrate 470, and is arranged via a plurality of wirings. It is possible to reduce interference between signals even when they are input.

1.9.2 Configuration of Second Wiring Layer FIG. 17 is a perspective view of the second wiring layer 472 of the relay substrate 340 as viewed from the first wiring layer 471 side.

  The second wiring layer 472 of the relay substrate 340 is a layer adjacent to the first wiring layer 471 and includes a constant potential wiring 436 and a plurality of vias.

  As shown in FIG. 17, the second wiring layer 472 of the relay substrate 340 is a reference potential layer of the relay substrate 340, and a constant potential wiring 436 such as a circuit ground is provided over substantially the front surface of the second layer. Thus, by making the constant potential wiring 436 wide and large, the reference potential of the relay substrate 340 can be stabilized, and the operation can be stabilized.

  The constant potential wiring 436 is connected to the control electrode 406 of the control signal connector 280 provided in the first wiring layer 471 through the via 426. As a result, the potential of the constant potential wiring 436 matches the reference potential of the control unit 10.

  At this time, in the present embodiment, in the plan view of the substrate 470, the second wiring layer 472 that overlaps the region where the control wirings 411, 412, 413, and 414 provided in the first wiring layer 471 are wired. Other wirings including the constant potential wiring 436 are not provided in the region.

  Since the constant potential wiring 436 is provided in common in the relay substrate 340, there is a possibility that slight fluctuation may occur due to a large amplitude voltage such as the drive signals COMA and COMB. On the other hand, the signals transferred through the control wirings 411, 412, 413, and 414 are the differential signals d1, d2, d3, and d4 of the LVDS transfer method as described above, and the amplitude of the signals is as small as about 350 mV. It is. For this reason, signals may interfere with each other due to weak fluctuations that occur in the constant potential wiring 436, which may cause problems.

  According to the present embodiment, the constant potential wiring 436 is not provided in the region where the control wirings 411, 412, 413, and 414 provided in the first wiring layer 471 are wired in the plan view of the substrate 470. The differential signals d1, d2, d3, and d4 transferred through the control wirings 411, 412, 413, and 414 can reduce the influence of the wiring including the constant potential wiring 436, and can improve the signal accuracy. There is.

In the present embodiment, the second wiring layer 472 includes the second via other than the via 426 as the second via.
The wiring layer is only inserted through, and the description thereof is omitted.

1.9.3 Configuration of Third Wiring Layer FIG. 18 is a perspective view of the third wiring layer 473 of the relay substrate 340 as viewed from the first wiring layer 471 side.

  As shown in FIG. 18, the third wiring layer 473 of the relay substrate 340 includes control wirings 431, 432, 433, and 434 and a plurality of vias.

  The control wiring 431 is connected to the via 421 and the via 441. The control wiring 431 is connected to the control signal receiving unit 260 via the via 421, and transfers, for example, the control signal c1 and the switching period designation signal RT to the via 441. The control signal c1 and the switching period designation signal RT are output from the input / output electrode 451 to the drive unit 320 including the head 20-1, for example, via the via 441.

  That is, the control wiring 431 is a wiring layer provided with wiring for transferring the drive signals COMA and COMB and the common voltage VBS, and a wiring layer formed with wiring for transferring the differential signals d1, d2, d3, and d4. A different third wiring layer 473 is provided.

  Similarly, the control wiring 432 is connected to the via 422 and the via 442. The control wiring 432 is connected to the control signal receiving unit 260 via the via 422, and transfers, for example, the control signal c2 and the switching period designation signal RT to the via 442. The control signal c2 and the switching period designation signal RT are output from the input / output electrode 452 to the drive unit 320 including, for example, the head 20-2 via the via 442.

  Similarly, the control wiring 433 is connected to the via 423 and the via 443. The control wiring 433 is connected to the control signal receiving unit 260 via the via 423, and transfers the control signal c3 and the switching period designation signal RT to the via 443, for example. The control signal c3 and the switching period designation signal RT are output from the input / output electrode 453 to the drive unit 320 including, for example, the head 20-3 via the via 443.

  Similarly, the control wiring 434 is connected to the via 424 and the via 444. The control wiring 434 is connected to the control signal receiving unit 260 via the via 424, and transfers, for example, the control signal c4 and the switching period designation signal RT to the via 444. The control signal c4 and the switching period designation signal RT are output from the input / output electrode 454 to the drive unit 320 including, for example, the head 20-4 via the via 444.

  In the present embodiment, the wiring for transferring the control signals c1, c2, c3, c4 and the switching period designation signal RT is the driving signal COMA for both the wiring layers provided with the wiring for transferring the differential signals d1, d2, d3, d4. , COMB, and the wiring layer provided with the wiring to which the common voltage VBS is transferred are provided in different wiring layers.

  Since each of the control signals c1, c2, c3, and c4 is composed of four signals, the number of wires transferred on the relay board 340 increases. According to the present embodiment, by providing the wiring for transferring the control signals c1, c2, c3, c4 and the switching period designation signal RT in separate layers, the wiring of the substrate 470 can be distributed and provided. Can be miniaturized.

1.9.4 Configuration of Fourth Wiring Layer, Fifth Wiring Layer, and Sixth Wiring Layer FIG. 19 shows the fourth wiring layer 474 of the relay substrate 340 viewed from the first wiring layer 471 side. FIG. FIG. 20 is a perspective view of the fifth wiring layer 475 of the relay substrate 340 as viewed from the first wiring layer 471 side. FIG. 21 is a perspective view of the sixth wiring layer 476 of the relay substrate 340 as viewed from the first wiring layer 471 side.

  The fourth wiring layer 474, the fifth wiring layer 475, and the sixth wiring layer 476 shown in FIGS. 19 to 21 are provided with wirings for transferring the drive signals COMA and COMB and the common voltage VBS. ing.

  A drive wiring 561 (an example of “fourth wiring”) illustrated in FIG. 19 is provided in the fourth wiring layer 474 (an example of “fourth layer”), and is connected to the via 521 and the via 541. For example, a drive signal COMA1 (an example of a “second drive signal”) is supplied to the via 521 via the drive electrode 501. The via 541 is connected to the input / output electrode 451 and is electrically connected to the drive unit 320 including, for example, the head 20-1 through the input / output electrode 451. That is, the drive wiring 561 transfers the drive signal COMA1 input from the drive electrode 501 to the drive unit 320 including the head 20-1, for example, via the input / output electrode 451.

  A drive wiring 562 (an example of “third wiring”) illustrated in FIG. 20 is provided in the fifth wiring layer 475 (an example of “third layer”), and is connected to the via 522 and the via 542. For example, a common voltage VBS (an example of a “reference voltage signal”) is supplied to the via 522 via the drive electrode 502. The via 542 is connected to the input / output electrode 451 and is electrically connected to the drive unit 320 including, for example, the head 20-1 through the input / output electrode 451. That is, the drive wiring 562 transfers the common voltage VBS input from the drive electrode 502 to the drive unit 320 including, for example, the head 20-1 via the input / output electrode 451.

  A driving wiring 563 (an example of “second wiring”) illustrated in FIG. 21 is provided in the sixth wiring layer 476 (an example of “second layer”), and is connected to the via 523 and the via 543. For example, a drive signal COMB1 is supplied to the via 523 through the drive electrode 503. The via 543 is connected to the input / output electrode 451 and is electrically connected to the drive unit 320 including, for example, the head 20-1 through the input / output electrode 451. That is, the drive wiring 563 transfers the drive signal COMB1 input from the drive electrode 503 to the drive unit 320 including, for example, the head 20-1 via the input / output electrode 451.

  That is, the drive wirings 561, 562, and 563 output a signal for driving the piezoelectric element 60 included in the ejection unit 600 of one head 20-1.

  Furthermore, the drive wiring 561 that transfers the drive signal COMA1, the drive wiring 563 that transfers the drive signal COMB2, and the drive wiring 562 that transfers the common voltage VBS respectively transfer the differential signals d1, d2, d3, and d4. Both the wiring layer provided with the control wirings 411, 412, 413, 414 and the wiring layer provided with the control wirings 431, 432, 433, 434 for transferring the control signals c 1, c 2, c 4, and the residual vibration signal The wiring layer provided with the wiring 415 is provided in a different wiring layer.

  A wiring layer to which differential signals d1, d2, d3, and d4 having weak voltages are transferred, a wiring layer to which control wirings 411, 412, 413, and 414 having small amplitude voltages are transferred, and a drive signal COMA1 having a large amplitude voltage. , COMB1, and the wiring layer to which the common voltage VBS is transferred are different wiring layers, so that mutual interference of signals can be reduced.

  Furthermore, the drive wirings 561, 562, and 563 in the present embodiment are the drive wiring 561 provided in the fourth wiring layer 474 and the driving wiring 562 provided in the fifth wiring layer 475 in the plan view of the substrate 470. Is provided so that at least a part thereof overlaps. In addition, the drive wiring 563 provided in the sixth wiring layer 476 and the drive wiring 562 provided in the fifth wiring layer 475 are provided so that at least a part thereof overlaps. In other words, the driving wiring 562 provided in the fifth wiring layer 475 includes the wiring area of the driving wiring 561 provided in the fourth wiring layer 474 and the wiring of the driving wiring 563 provided in the sixth wiring layer 476. It is provided so that at least a part thereof overlaps with a region facing the region.

  In the present embodiment, the current flowing in the drive wiring 561 and the drive wiring 563 that transfer the drive signal COMA1 and the drive signal COMB1 and the current flowing in the drive wiring 562 that transfers the common voltage VBS flow in different directions. For this reason, the drive wiring 561, the drive wiring 563, and the drive wiring 562 are arranged so as to face each other in the adjacent wiring layer in the substrate 470, thereby causing a current to flow through the drive wiring 561 and the drive wiring 563. The electromagnetic field generated by the current flowing through the drive wiring 562 is canceled out. As a result, impedance generated in the drive wiring 561, the drive wiring 562, and the drive wiring 563 is reduced, and the ejection characteristics can be stabilized.

  Furthermore, the piezoelectric element 60 included in the head 20-1 in the present embodiment is driven by a potential difference between the drive voltage Vout based on the drive signals COMA1 and COMB1 and the common voltage VBS. As in this embodiment, the wiring layer provided with the driving wiring 562 to which the common voltage VBS is transferred is divided into the wiring layer provided with the driving wiring 561 to which the driving signal COMA1 is transferred, and the driving wiring 562 to which the driving signal COMB1 is transferred. The wiring layer between the driving signal COMA1 and the common voltage VBS, and the correlation between the driving signal COMB1 and the common voltage VBS can be made substantially constant. Accordingly, the piezoelectric element 60 included in the head 20-1 can be stably driven.

  A drive wiring 564 shown in FIG. 19 is provided in the fourth wiring layer 474 and connected to the via 524 and the via 544. For example, a drive signal COMA 2 is supplied to the via 524 via the drive electrode 504. The via 544 is connected to the input / output electrode 452, and is electrically connected to the drive unit 320 including, for example, the head 20-2 via the input / output electrode 452. That is, the drive wiring 564 transfers the drive signal COMA2 input from the drive electrode 504 to the drive unit 320 including, for example, the head 20-2 via the input / output electrode 452.

  A driving wiring 565 illustrated in FIG. 20 is provided in the fifth wiring layer 475 and is connected to the via 525 and the via 545. For example, the common voltage VBS is supplied to the via 525 via the drive electrode 505. The via 545 is connected to the input / output electrode 452, and is electrically connected to the drive unit 320 including, for example, the head 20-2 via the input / output electrode 452. That is, the drive wiring 564 transfers the common voltage VBS input from the drive electrode 504 to the drive unit 320 including the head 20-2, for example, via the input / output electrode 452.

  A drive wiring 566 shown in FIG. 21 is provided in the sixth wiring layer 476 and connected to the via 526 and the via 546. For example, a drive signal COMB <b> 2 is supplied to the via 526 through the drive electrode 506. The via 546 is connected to the input / output electrode 452, and is electrically connected to the drive unit 320 including, for example, the head 20-2 via the input / output electrode 452. That is, the drive wiring 566 transfers the drive signal COMB2 input from the drive electrode 506 to the drive unit 320 including the head 20-2, for example, via the input / output electrode 452.

  That is, the drive wirings 564, 565, and 566 output a signal for driving the piezoelectric element 60 included in the ejection unit 600 of one head 20-2. Further, like the drive wirings 561, 562, and 563, the drive wirings 564 and 565 are arranged so that at least a part of the respective wiring areas overlap in plan view, and the drive wirings 565 and 566 are also shown in plan view. In this case, it is possible to stabilize the ejection characteristics by arranging the wiring regions so that at least a part of them overlaps.

  A drive wiring 567 shown in FIG. 19 is provided in the fourth wiring layer 474 and connected to the via 527 and the via 547. For example, a drive signal COMA 3 is supplied to the via 527 through the drive electrode 507. The via 547 is connected to the input / output electrode 453 and is electrically connected to the drive unit 320 including, for example, the head 20-3 via the input / output electrode 453. That is, the drive wiring 567 transfers the drive signal COMA3 input from the drive electrode 507 to the drive unit 320 including the head 20-3, for example, via the input / output electrode 453.

  A drive wiring 568 shown in FIG. 20 is provided in the fifth wiring layer 475 and connected to the via 528 and the via 548. For example, a common voltage VBS is supplied to the via 528 via the drive electrode 508. The via 548 is connected to the input / output electrode 453 and is electrically connected to the drive unit 320 including, for example, the head 20-3 via the input / output electrode 453. That is, the drive wiring 568 transfers the common voltage VBS input from the drive electrode 508 to the drive unit 320 including, for example, the head 20-3 via the input / output electrode 453.

  A drive wiring 569 shown in FIG. 21 is provided in the sixth wiring layer 476 and connected to the via 529 and the via 549. For example, a drive signal COMB3 is supplied to the via 529 via the drive electrode 509. The via 549 is connected to the input / output electrode 453 and is electrically connected to the drive unit 320 including, for example, the head 20-3 via the input / output electrode 453. That is, the drive wiring 569 transfers the drive signal COMB3 input from the drive electrode 509 to the drive unit 320 including the head 20-3, for example, via the input / output electrode 453.

  That is, the drive wirings 567, 568, and 569 output signals for driving the piezoelectric elements 60 included in the ejection unit 600 of one head 20-3. Further, like the drive wirings 561, 562, and 563, the drive wirings 567 and 568 are arranged so that at least a part of the respective wiring regions overlap in plan view, and the drive wirings 568 and 569 are also shown in plan view. In this case, it is possible to stabilize the ejection characteristics by arranging the wiring regions so that at least a part of them overlaps.

  A drive wiring 570 illustrated in FIG. 19 is provided in the fourth wiring layer 474 and is connected to the via 530 and the via 550. For example, a drive signal COMA 4 is supplied to the via 530 through the drive electrode 510. The via 550 is connected to the input / output electrode 454 and is electrically connected to the drive unit 320 including, for example, the head 20-4 via the input / output electrode 454. That is, the drive wiring 570 transfers the drive signal COMA4 input from the drive electrode 510 to the drive unit 320 including, for example, the head 20-4 via the input / output electrode 454.

  A drive wiring 571 illustrated in FIG. 20 is provided in the fifth wiring layer 475 and is connected to the via 531 and the via 551. For example, the common voltage VBS is supplied to the via 531 via the drive electrode 511. The via 551 is connected to the input / output electrode 454, and is electrically connected to the drive unit 320 including the head 20-4 through the input / output electrode 454, for example. That is, the drive wiring 571 transfers the common voltage VBS input from the drive electrode 511 to the drive unit 320 including, for example, the head 20-4 via the input / output electrode 454.

  A driving wiring 572 illustrated in FIG. 21 is provided in the sixth wiring layer 476 and is connected to the via 532 and the via 552. For example, a drive signal COMB 4 is supplied to the via 532 through the drive electrode 512. The via 552 is connected to the input / output electrode 454, and is electrically connected to the drive unit 320 including the head 20-4 through the input / output electrode 454, for example. That is, the drive wiring 572 transfers the drive signal COMB4 input from the drive electrode 512 to the drive unit 320 including, for example, the head 20-4 via the input / output electrode 454.

  That is, the drive wirings 570, 571, and 572 output a signal for driving the piezoelectric element 60 included in the ejection unit 600 of one head 20-4. Further, like the drive wirings 561, 562, and 563, the drive wirings 570 and 571 are arranged so that at least a part of the respective wiring regions overlap in plan view, and the drive wirings 571 and 572 are also shown in plan view. In this case, it is possible to stabilize the ejection characteristics by arranging the wiring regions so that at least a part of them overlaps.

1.10 Action / Effect As described above, in the liquid ejection apparatus 1 according to the present embodiment, in the relay substrate 340, the residual vibration signal wiring 415 that transfers the residual vibration signal Vrbg and the drive that transfers the drive signal COMB1. The wiring 561 is provided in a different wiring layer. Therefore, according to the liquid ejection apparatus 1 according to the present embodiment, in the relay substrate 340, due to the mutual interference between the residual vibration signal Vrbg transferred by the residual vibration signal wiring 415 and the drive signal COMB1 transferred by the drive wiring 561. Therefore, the possibility that the residual vibration signal Vrbg is deteriorated can be reduced, and the state of the ejection unit 600 can be detected with high accuracy.

  In the liquid ejection apparatus 1 according to the present embodiment, the input / output electrodes 451 to which the residual vibration signal Vrbg is input, the residual vibration signal wiring 415 to which the residual vibration signal Vrbg is transferred, and the residual vibration signal are provided on the relay substrate 340. A control signal connector 280 that outputs Vrbg is provided in the same layer (first wiring layer) of the relay substrate 340. Accordingly, a via or the like for connecting to another wiring layer of the relay substrate 340 is not necessary, and the possibility that the residual vibration signal Vrbg is deteriorated can be further reduced, and the state of the ejection unit 600 can be detected with high accuracy. it can.

  In the liquid ejection apparatus 1 according to the present embodiment, the residual vibration signal wiring 415 includes the residual vibration signal Vrbg-1 output from the piezoelectric element 60 included in the ejection unit 600 of the head 20-1, and the head 20-2. The residual vibration signal Vrbg-2 output from the piezoelectric element 60 included in the discharge unit 600 is transferred in a time division manner. As a result, the number of wires for transferring the residual vibration signal Vrbg can be reduced, and the circuit board can be reduced in size.

2 Second Embodiment Next, a liquid ejection apparatus 1 according to a second embodiment will be described. The liquid ejection apparatus 1 of the second embodiment has basically the same configuration as the liquid ejection apparatus 1 according to the first embodiment, but the residual vibration signal Vrbg output from the head unit 32 is output as a digital signal. The point is different. Below, the description which overlaps with 1st Embodiment is abbreviate | omitted or simplified, and the content different from 1st Embodiment is mainly demonstrated. In addition, the same code | symbol is attached | subjected to the same component, the description which overlaps with 1st Embodiment is abbreviate | omitted, and the content different from 1st Embodiment is demonstrated.

  Since the schematic configuration of the liquid ejection apparatus 1 of the second embodiment is the same as that of the first embodiment (FIGS. 1 to 3), description and illustration thereof are omitted. About the structure of the discharge part 600 of 2nd Embodiment, and the waveform of a drive signal and the drive voltage Vout, it is the same as that of 1st Embodiment (FIGS. 6-8), The description and illustration are abbreviate | omitted. The configurations of the selection control unit 210, the selection unit 230, the switching unit 250, and the amplification output unit 240 of the second embodiment are the same as those of the first embodiment (FIGS. 9 to 14), and the description and illustration thereof are omitted. To do. The configuration of the head unit of the second embodiment is the same as that of the first embodiment (FIG. 15), and the description and illustration thereof are omitted.

The electrical configuration of the liquid ejection apparatus 1 according to the second embodiment is partially different in the head unit 32. The electrical configuration of the control unit 10 in the liquid ejection apparatus 1 of the second embodiment is the same as that of the first embodiment (FIG. 4), and the description and illustration thereof are omitted. FIG. 22 is a block diagram illustrating an electrical configuration of the head unit 32 in the liquid ejection apparatus 1 according to the second embodiment.

  The head unit 32 in the second embodiment includes an A / D conversion unit 270 in the path where the residual vibration signal Vrbg is output.

  The A / D converter 270 (an example of an “AD converter circuit”) receives the residual vibration signal Vrbg, which is an analog signal output from the amplification output unit 240, converts the residual vibration signal Vrbg into a digital signal, and a state signal determination unit of the control unit 10 120 is output.

  The A / D converter 270 receives an analog residual vibration signal Vrbg and converts it into a digital signal using a comparator such as a comparator. Thereafter, the converted digital signal is output to the state signal determination unit 120 shown in FIG.

  FIG. 23 is a plan view showing the configuration of the first wiring layer 471 of the substrate 470 in the second embodiment.

  The A / D converter 270 is provided in the residual vibration signal wiring 415 in the first wiring layer of the substrate 470. Specifically, one end of the A / D converter 270 is connected to the control electrode 406 via the residual vibration signal wiring 415. The other end of the A / D converter 270 is connected to the input / output electrodes 451, 452, 453, and 454 via the residual vibration signal wiring 415. That is, the residual vibration signal Vrbg is input to the relay board 340 from each of the input / output electrodes 451, 452, 453, 454, converted into a digital signal by the A / D conversion unit 270, and from the control signal connector 280 including the control electrode 406. The signal is input to the state signal determination unit 120 via the flexible flat cable 191.

  According to the liquid ejection device 1 of the second embodiment, the residual vibration signal Vrbg is converted into a digital signal in the relay substrate 340 and then the state signal determination unit 120 included in the control unit 10 via the flexible flat cable 191. Therefore, the deterioration of the residual vibration signal Vrbg due to noise or the like in the flexible flat cable 191 can be reduced, and the liquid can be discharged with high accuracy.

  In the second embodiment, the second wiring layer 472, the third wiring layer 473, the fourth wiring layer 474, the fifth wiring layer 475, and the sixth wiring layer 476 of the relay substrate 340 are This is the same as in the first embodiment, and the description and illustration thereof are omitted.

  In the second embodiment, the signal output from the A / D converter 270 is output from one residual vibration signal wiring 415 and one control electrode 406. The digital signal output from the A / D conversion unit 270 may be a digital signal in a parallel format. When the digital signal is output as a parallel signal, the residual vibration signal wiring 415 connected to the A / D conversion unit 270 includes a plurality of wirings. The control electrode 405 may also be constituted by a plurality of electrodes.

In the second embodiment, the A / D converter 270 is a one-chip IC (Integrated).
Circuit) or a plurality of parts. In addition, the control signal receiving unit 260 may be included in a one-chip IC.

  As mentioned above, although this embodiment or the modification was demonstrated, this invention is not limited to these this embodiment or a modification, It is possible to implement in a various aspect in the range which does not deviate from the summary. For example, it is possible to appropriately combine the above-described embodiment and each modification.

  The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 1 ... Liquid discharge apparatus, 3 ... Base, 4 ... Liquid storage means, 5 ... 1st conveyance means, 6 ... 2nd conveyance means, 7 ... Apparatus main body, 8 ... Supply pipe, 10 ... Control unit, 20 ... Head, 32 DESCRIPTION OF SYMBOLS ... Head unit, 40 ... 1st conveyance motor driver, 41 ... 1st drive motor, 42 ... 1st conveyance roller, 43 ... 1st driven roller, 50 ... Drive circuit, 60 ... Piezoelectric element, 70 ... 2nd conveyance motor driver 71 ... second drive motor, 72 ... second transport roller, 73 ... second driven roller, 74 ... transport belt, 75 ... tension roller, 76 ... biasing member, 80 ... maintenance unit, 81 ... cleaning mechanism, 82 ... Wiping mechanism, 100 ... control unit, 110 ... control signal transmission unit, 120 ... status signal determination unit, 170,280 ... control signal connector, 180,290 ... drive signal Connector, 190, 191 ... Flexible flat cable, 210 ... Selection control unit, 212 ... Shift register, 214 ... Latch circuit, 216 ... Decoder, 230 ... Selection unit, 232 ... Inverter, 234 ... Transfer gate, 236 ... AND circuit, 240 ... Amplification output unit, 250 ... Switching unit, 252 ... Switch, 260 ... Control signal receiving unit, 270 ... A / D conversion unit, 310 ... Head body, 320 ... Drive unit, 322 ... Drive wiring, 330 ... Holder, 332 ... Communicating flow path, 333 ... wiring insertion hole, 340 ... relay board, 341 ... drive wiring connection hole, 342 ... insertion hole, 343, 344 ... connector, 350 ... supply member, 352 ... supply flow path, 353 ... through hole, 360 ... Fixing plate, 361 ... Exposed opening, 370 ... Channel member, 390 ... Filter unit 395: Flow path member, 401, 402, 403, 404, 405, 406: Control electrode, 410: Termination resistance, 411, 412, 413, 414, 431, 432, 433, 434 ... Control wiring, 415: Residual vibration Signal wiring, 436 ... constant potential wiring, 451, 452, 453, 454 ... input / output electrodes, 470 ... substrate, 471 ... first wiring layer, 472 ... second wiring layer, 473 ... third wiring layer, 474 ... 4th wiring layer, 475 ... 5th wiring layer, 476 ... 6th wiring layer, 481,482 ... short side, 483,484 ... long side, 501,502,503,504,505,506,507 , 508, 509, 510, 511, 512... Drive electrode, 561, 562, 563, 564, 565, 566, 567, 568, 569, 570, 571, 572. 21,422,423,424,426,441,442,443,444,521,522,523,524,525,526,527,528,529,530,531,532,541,542,543,544 545, 546, 547, 548, 549, 550, 551, 552 ... via, 600 ... discharge portion, 601 ... piezoelectric body, 611,612 ... electrode, 621 ... vibrating plate, 631 ... cavity, 632 ... nozzle plate, 641 ... Reservoir, 651 ... Nozzle, 661 ... Supply port, S ... Recording sheet, COMA, COMB ... Drive signal

Claims (6)

A first ejection unit that includes a first piezoelectric element and that operates based on a first drive signal that drives the first piezoelectric element;
A circuit board for transferring the first drive signal and a first residual vibration signal indicating a first residual vibration generated after the first piezoelectric element is driven by the first drive signal;
A determination circuit for determining a state of the first discharge unit based on the first residual vibration signal;
With
The circuit board is
A first wiring for transferring the first residual vibration signal;
A second wiring for transferring the first drive signal;
A first input terminal connected to the first wiring and for inputting the first residual vibration signal to the circuit board;
A first output terminal connected to the first wiring and outputting the first residual vibration signal to the determination circuit;
Including
The first wiring, the first input terminal, and the first output terminal are formed on a first layer of the circuit board,
The second wiring is provided in a second layer different from the first layer;
A liquid discharge apparatus characterized by that. The circuit board is
An AD conversion circuit for converting the first residual vibration signal into a digital signal;
The AD conversion circuit is provided in the first layer,
The first wiring is connected to the first output terminal via the AD conversion circuit.
The liquid ejection apparatus according to claim 1, wherein A second discharge unit including a second piezoelectric element and operating by driving the second piezoelectric element;
The first wiring transfers the first residual vibration signal and a second residual vibration signal indicating a second residual vibration generated after the second piezoelectric element is driven in a time division manner. Item 3. The liquid ejection device according to Item 1 or 2. The circuit board is
A third layer different from the first layer and the second layer;
A third wiring that transfers a reference voltage signal that is applied to the other end different from the one end to which the first drive signal of the first piezoelectric element is applied, and supplies a reference voltage;
Including
The third wiring is provided in the third layer,
In a plan view of the circuit board,
The third wiring and the second wiring are provided so as to at least partially overlap each other.
The liquid discharge apparatus according to claim 1, wherein the liquid discharge apparatus is a liquid discharge apparatus. A second drive signal for driving the first piezoelectric element;
The circuit board is
A fourth wiring for transferring the second drive signal;
A fourth layer different from the first layer, the second layer, and the third layer;
Including
The fourth wiring is provided in the fourth layer,
The third layer is provided between the second layer and the fourth layer,
In a plan view of the circuit board,
The third wiring and the fourth wiring are provided so that at least a part thereof overlaps,
The liquid ejecting apparatus according to claim 4, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. A first wiring for detecting a first residual vibration generated after the first piezoelectric element is driven by the first drive signal and transferring a first residual vibration signal indicating the first residual vibration;
A second wiring for transferring the first drive signal for driving the first piezoelectric element;
A first input terminal connected to the first wiring and for inputting the first residual vibration signal;
A first output terminal connected to the first wiring and outputting the first residual vibration signal;
Including
The first wiring, the first input terminal, and the first output terminal are formed in a first layer,
The second wiring is provided in a second layer different from the first layer;
A circuit board characterized by that.