JP2019116043A - Liquid ejection device - Google Patents

Abstract

A liquid ejection apparatus capable of reducing variation in delay of signals transferred by a plurality of cables. A board provided with a first connector and a second connector, a third connector to which a first signal is transferred, and a second signal provided side by side with the third connector in a first direction. A fourth connector to be transferred; and a plurality of nozzles from which liquid is ejected, wherein the ejection head provided apart from the substrate in the first direction; and the first connector and the third connector are electrically connected And a second cable that electrically connects the second connector and the fourth connector and has the same length as the first cable. [Selection] Figure 18

Description

  The present invention relates to a liquid discharge device.

  2. Related Art An ink jet printer that prints an image or a document by discharging a liquid such as ink is known using a piezoelectric element (for example, a piezoelectric element). The piezoelectric element is provided corresponding to each of the plurality of nozzles in the print head, and each is driven according to the drive signal to eject a predetermined amount of liquid from the nozzles at a predetermined timing to dot the medium. Form The piezoelectric elements are electrically capacitively loaded like capacitors, and it is necessary to supply sufficient current to operate the piezoelectric elements of each nozzle.

  Patent Document 1 and Patent Document 2 disclose a technology in which ink is ejected from a nozzle opening by providing a piezoelectric element in a head main body (ejection head) and causing pressure change in a pressure generation chamber by driving the piezoelectric element. ing.

Patent No. 5181898 gazette JP, 2011-207180, A

  In such an ejection head, in recent years, high-speed and high-definition printing requirements of liquid ejection devices, specifically, high-speed over 30 ipm (hereinafter referred to as high-speed) and high precision over 600 dpi (hereinafter high-precision) Printing requirements are increasing. In response to such high-speed and high-precision printing requirements, high-speed printing by increasing the number of nozzles based on miniaturization of piezoelectric elements using MEMS technology, and high-precision printing by densifying nozzles We have responded by making it possible.

  As the density of nozzles and the number of nozzles increase, the number of signals supplied to the ejection head increases, and the number of wires for transferring the signal supplied to the ejection head also increases. Therefore, there is known a technique for transferring a signal supplied to the discharge head using a plurality of cables. In this case, the mutual interference of the transferred signals is reduced by transferring the high voltage signal and the low voltage signal by different cables.

  However, when transferring a signal through a cable, a delay occurs in the transferred signal due to the impedance component of the cable. Therefore, when the high voltage drive signal and the low voltage control signal are transferred by different cables and there is a variation in the impedance component of each transferred cable, the delay time of the drive signal transferred by the different cables And the delay time of the control signal are different. As a result, the timing at which the drive signal and the control signal transferred by different cables are supplied to the discharge head varies, resulting in a new problem that the discharge accuracy of the liquid may be deteriorated.

  According to some aspects of the present invention, it is possible to provide a liquid discharge device capable of reducing variations in delay time of signals transferred by a plurality of cables.

  The present invention has been made to solve at least a part of the above-mentioned problems, and it is possible to realize the following aspects or applications.

Application Example 1
The liquid discharge apparatus according to the application example includes a substrate provided with a first connector and a second connector, a third connector to which a first signal is transferred, and the third connector in a first direction. And a plurality of nozzles through which a second signal is transferred, and a plurality of nozzles through which liquid is discharged, and a discharge head provided to be separated from the substrate in the first direction, the first connector, and A first cable electrically connecting to a third connector, a second cable electrically connecting the second connector and the fourth connector, and having the same length as the first cable are included.

  "Same length" is a concept including the case where it can be regarded as substantially the same length.

  In the liquid discharge apparatus according to this application example, the first cable electrically connecting the first connector provided on the substrate and the third connector provided on the discharge head, the second connector provided on the substrate, and the discharge Since the second cable electrically connecting to the fourth connector provided on the head has the same length, the variation in the impedance component between the first cable and the second cable is reduced. Therefore, the delay time caused by the impedance component of the first cable transferred by the first cable and the impedance component of the second cable transferred by the second cable, of the second signal Variations in delay time can be reduced.

  Further, in the liquid discharge apparatus according to this application example, the third connector and the fourth connector are provided side by side in the first direction on the discharge head provided to be separated from the substrate in the first direction. Therefore, it is possible to miniaturize the discharge head in the direction intersecting the first direction. Therefore, it is possible to electrically connect the substrate and the discharge head by the first cable and the second cable having the same length while reducing an increase in the size of the discharge head.

Application Example 2
In the liquid discharge device according to the application example, the first connector and the second connector are provided side by side in a second direction intersecting the first direction, and the first connector and the second connector in the second direction are provided. The distance to the connector may be the same as the distance between the third connector and the fourth connector in the first direction.

  “Same as distance” is a concept including the case where it can be regarded as substantially the same distance.

  In the liquid discharge apparatus according to this application example, the distance between the first connector and the second connector provided on the substrate is the same as the distance between the third connector and the fourth connector provided on the discharge head. It is possible to reduce the difference between the distance between the first connector and the third connector to which the first cable is connected and the distance between the second connector and the fourth connector to which the second cable is connected. For this reason, it is possible to make the lengths of the first cable and the second cable the same and to shorten the lengths of the first cable and the second cable. Therefore, it becomes possible to reduce the impedance component which arises in each of the 1st cable and the 2nd cable. Therefore, the delay time caused by the impedance component of the first cable transferred by the first cable and the impedance component of the second cable transferred by the second cable, of the second signal Variations in delay time can be further reduced.

Application Example 3
In the liquid discharge device according to the application example, the distance between the first connector and the discharge head in the second direction is larger than the distance between the second connector and the discharge head, and in the first direction, The distance between the third connector and the substrate may be smaller than the distance between the fourth connector and the substrate.

  In the liquid ejection apparatus according to this application example, the second connector provided on the substrate is provided closer to the ejection head than the first connector, and the third connector provided on the ejection head is provided on the substrate side relative to the fourth connector Provided in Therefore, it is possible to further reduce the difference between the distance between the first connector and the third connector to which the first cable is connected and the distance between the second connector and the fourth connector to which the second cable is connected. It becomes. Therefore, it becomes possible to further reduce the impedance component which arises in each of the 1st cable and the 2nd cable. Therefore, the delay time caused by the impedance component of the first cable transferred by the first cable and the impedance component of the second cable transferred by the second cable, of the second signal Variations in delay time can be further reduced.

Application Example 4
In the liquid discharge device according to the application example, even if a plurality of the substrate, the discharge head, the first cable, and the second cable are provided in the third direction intersecting the first direction and the second direction. Good.

  In the liquid discharge apparatus according to the application example, the third connector and the fourth connector are provided side by side in the first direction in the discharge head provided to be separated from the substrate in the first direction. For this reason, the discharge head can be miniaturized in the direction intersecting the first direction. Therefore, even in the liquid discharge apparatus in which the plurality of substrates, the discharge head, the first cable, and the second cable are provided, an increase in the mounting area of the configuration can be reduced. Therefore, the liquid discharge apparatus is provided with a plurality of substrates, a discharge head, a first cable, and a second cable, and the liquid discharge apparatus is large even if the first cable and the second cable have the same length. Can be reduced.

  Further, in the liquid discharge apparatus according to the application example, even when the plurality of substrates, the discharge head, the first cable, and the second cable are provided, the discharge head may be provided in the direction intersecting the first direction. Since miniaturization is possible, it is possible to provide many discharge heads even when the mountable area of the discharge head is the same in the liquid discharge apparatus. Therefore, it becomes possible to discharge the liquid with high definition.

Application Example 5
In the liquid ejection apparatus according to the application example, the ejection head may be provided with a plurality of ejection modules provided with 300 or more and 600 or more of the nozzles per inch.

  In the liquid discharge apparatus according to this application example, even when the discharge head includes a plurality of discharge modules provided with 300 or more nozzles and 600 or more nozzles per inch, the first cable and the second cable Since the lengths are the same, and variations in impedance components of the first cable and the second cable can be reduced, the delay time of the first signal transferred by the first cable due to the impedance component of the first cable and The variation of the second signal transferred by the second cable with the delay time due to the impedance component of the second cable can be reduced.

Application Example 6
The liquid discharge apparatus according to the application example includes a substrate provided with a first connector and a second connector, a third connector to which a first signal is transferred, and the third connector in a first direction. And a plurality of nozzles through which a second signal is transferred, and a plurality of nozzles through which liquid is discharged, and a discharge head provided to be separated from the substrate in the first direction, the first connector, and A first cable electrically connecting a third connector, and a second cable electrically connecting the second connector and the fourth connector, wherein the liquid is discharged from the nozzle The first connector and the second connector are provided side by side in two directions, and the first connector is farther from the discharge head than the second connector in the second direction. The fourth connector is provided farther from the substrate than the third connector in the first direction, and the distance between the first connector and the second connector in the second direction is the first connector. It is the same as the distance between the third connector and the fourth connector in the direction.

  “Same as distance” is a concept including the case where it can be regarded as substantially the same distance.

  In the liquid discharge device according to the application example, the first connector and the second connector provided on the substrate are juxtaposed in the second direction, and the third connector and the fourth connector provided in the discharge head are in the first direction. Side by side. At this time, the distance between the first connector and the second connector is the same as the distance between the third connector and the fourth connector, and the second connector is provided closer to the discharge head than the first connector, and The three connectors are provided closer to the substrate than the fourth connector. Thus, the difference between the distance between the first connector and the third connector to which the first cable is connected and the distance between the second connector and the fourth connector to which the second cable is connected can be reduced. Therefore, it is possible to reduce the increase in the length of the first cable and the second cable, and to make the lengths of the first cable and the second cable the same. The impedance components of the first and second cables can be reduced, and variations in the impedance components of the first and second cables can be reduced.

  Therefore, the delay time caused by the impedance component of the first cable transferred by the first cable and the impedance component of the second cable transferred by the second cable, of the second signal Variations in delay time can be reduced.

It is a side view which shows the structure of a liquid discharge apparatus. FIG. 6 is a side view showing a peripheral configuration of a printing unit of the liquid discharge device. FIG. 6 is a front view showing a peripheral configuration of a printing unit of the liquid discharge device. FIG. 6 is a perspective view showing a peripheral configuration of a printing unit of the liquid discharge device. It is a block diagram which shows the electric constitution of a liquid discharge apparatus. It is a figure which shows schematic structure of a discharge part. It is a figure which shows an example of the waveform of drive voltage COM-A and COM-B. It is a figure which shows an example of the waveform of drive voltage Vout. It is a figure which shows the structure of a drive signal selection circuit. It is a figure which shows the decoding content in a decoder. It is a figure which shows the structure of a selection circuit. It is a figure for demonstrating the operation | movement of a drive signal selection circuit. It is an exploded perspective view of a discharge head. It is the disassembled perspective view which looked at the discharge head from the nozzle formation surface. It is a top view which shows the nozzle formation surface of a discharge head. FIG. 6 is a diagram showing an example of a drive voltage Vout, a latch signal LAT, and a change signal CH in the drive circuit board. FIG. 6 is a view showing an example of a drive voltage Vout supplied to the ejection head, a latch signal LAT, and a change signal CH. It is a side view which shows the connection of a drive circuit board and a discharge head. It is a top view which shows the connection of a drive circuit board and a discharge head.

  Hereinafter, preferred embodiments of the present invention will be described using the drawings. The drawings used are for convenience of illustration. Note that the embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are necessarily essential configuration requirements of the present invention.

  Hereinafter, the liquid ejection apparatus according to the present invention will be described by taking an inkjet printer, which is a printing apparatus, as an example.

1. Outline of Liquid Ejection Device The configuration of the liquid ejection device 1 in the present embodiment will be described using FIGS. 1 to 4.

  FIG. 1 is a side view showing the configuration of the liquid ejection device 1. FIG. 2 is a side view showing the peripheral configuration of the printing unit 6 of the liquid discharge device 1. FIG. 3 is a front view showing the peripheral configuration of the printing unit 6 of the liquid ejection device 1. FIG. 4 is a perspective view showing the peripheral configuration of the printing unit 6 of the liquid discharge device 1.

  As shown in FIG. 1, the liquid discharge apparatus 1 includes a delivery unit 3 for delivering the medium M, a support unit 4 for supporting the medium M, a transport unit 5 for transporting the medium M, and a printing unit for printing on the medium M 6 and a control unit 2 that controls these configurations.

  In the following description, the width direction of the liquid ejection device 1 is referred to as “scanning direction X” (an example of “third direction”), and the depth direction of the liquid ejection device 1 is referred to as “front Y direction” (“first direction”). In the example, the height direction of the liquid ejection device 1 is “vertical direction Z” (an example of “second direction”), and the direction in which the medium M is transported is “transport direction F”. The scanning direction X, the longitudinal direction Y, and the vertical direction Z are directions intersecting each other (perpendicularly), and the transport direction F is a direction intersecting the scanning direction X (perpendicularly).

  The feeding unit 3 has a holding member 31 which rotatably holds a roll R on which the medium M is wound and stacked. The holding member 31 holds different types of media M and roll bodies R having different dimensions in the scanning direction X. Then, in the feeding unit 3, the medium M unwound from the roll R is fed toward the support 4 by rotating the roll R in one direction (clockwise direction in FIG. 1).

  The support portion 4 includes a first support portion 41, a second support portion 42, and a third support portion 43, which constitute a transport path of the medium M, from the upstream to the downstream in the transport direction F. The first support portion 41 guides the medium M delivered from the delivery portion 3 toward the second support portion 42, and the second support portion 42 supports the medium M on which printing is performed, and a third support portion 43 Guides the printed medium M downstream in the transport direction F.

  The transport unit 5 includes a transport roller 52 that applies a transport force to the medium M, a driven roller 53 that presses the medium M against the transport roller 52, and a rotation mechanism 51 that drives the transport roller 52. The transport roller 52 and the driven roller 53 are rollers having the scanning direction X as an axial direction.

  The transport roller 52 is disposed below the vertical direction Z of the transport path of the medium M, and the driven roller 53 is disposed above the vertical direction Z of the transport path of the medium M. The rotation mechanism 51 is configured by, for example, a motor and a reduction gear. Then, in the conveyance unit 5, the medium M is conveyed in the conveyance direction F by rotating the conveyance roller 52 in a state where the medium M is nipped by the conveyance roller 52 and the driven roller 53.

  As shown in FIGS. 2 and 3, the printing unit 6 includes a guide member 62 extending along the scanning direction X, a carriage 71 supported by the guide member 62 movably along the scanning direction X, and a carriage 71. A plurality of (five in the present embodiment) discharge heads 40 that are supported and discharge ink (liquid) onto the medium M and a moving mechanism 61 that moves the carriage 71 in the scanning direction X are provided.

  Further, the printing unit 6 is supported by the carriage 71, the drive circuit board 30, the control circuit board 20, the heat dissipation case 81 accommodating the drive circuit board 30 and the control circuit board 20, and the maintenance of the ejection heads 40. And a maintenance unit 91 that performs the

  The carriage 71 is a carriage cover 73 which forms a closed space by a carriage body 72 having an L-shaped cross section when viewed in the scanning direction X, and the carriage body 72 detachably attached to the carriage body 72. And A plurality of discharge heads 40 are supported at the lower part of the carriage 71 in a state of being arranged at equal intervals in the scanning direction X, and the lower end of each discharge head 40 protrudes from the lower surface of the carriage 71 to the outside. On the lower surface of each ejection head 40, a plurality of nozzles 651 (an example of a "nozzle") from which ink is ejected is opened in an arrayed state.

  Each ejection head 40 (an example of “ejection head”) is a so-called ink jet head having pressure generating means (piezoelectric element) for ejecting ink for each nozzle 651, and each nozzle 651 is supported by the carriage 71. Is directed to the second support portion 42. The moving mechanism 61 includes a motor and a reduction gear, and converts the rotational force of the motor into a moving force in the scanning direction X of the carriage 71. Therefore, the carriage 71 reciprocates in the scanning direction X while supporting the plurality of ejection heads 40, the plurality of drive circuit boards 30, and the control circuit board 20 by driving the moving mechanism 61.

  As shown in FIG. 2 and FIG. 4, the front end portion of a rectangular parallelepiped heat dissipation case 81 accommodating each drive circuit board 30 and control circuit board 20 is fixed to the upper end portion of the rear portion of the carriage 71.

  The control circuit board 20 is supported by the carriage 71 via the heat dissipation case 81. A connector 29 is provided on the control circuit board 20.

  The control unit 2 and the connector 29 are connected via a cable 65. That is, the cable 65 electrically connects the control circuit board 20 supported by the carriage 71 reciprocatingly moving in the scanning direction X, and the control unit 2 fixed to the liquid discharge device 1. Therefore, the cable 65 is preferably configured by an FFC (Flexible Flat Cable) that deforms following the reciprocating movement of the carriage 71.

  Further, a plurality of drive circuit boards 30 are provided upright and arranged above the control circuit board 20 in the vertical direction Z. The control circuit board 20 and each drive circuit board 30 are connected by a B to B (Board to Board) connector 83.

A plurality of drive circuit boards 30 (an example of a “board”) is supported by the carriage 71 via a heat dissipation case 81. In detail, the plurality of drive circuit boards 30 are supported by the heat dissipation case 81 in a state of being arranged at equal intervals in the scanning direction X. At this time, the arrangement direction of the plurality of drive circuit boards 30 and the arrangement direction of the plurality of ejection heads 40 are the same. That is, the drive circuit substrate 30 and the ejection head 40 correspond to each other, and are arranged in parallel while being supported by the carriage 71.

  Each drive circuit board 30 is provided with FFC connectors 84 and 85 at its front end. Each of the FFC connectors 84 and 85 is exposed to the carriage 71 from the front surface of the heat dissipation case 81.

  One end of a cable 86 (an example of a "first cable") configured by an FFC or the like is detachably connected to the FFC connector 84 (an example of the "first connector"), and the FFC connector 85 (a "second connector" One end of a cable 87 (an example of a “second cable”) configured by an FFC or the like is detachably connected to

  The discharge head 40 includes a discharge head main body 45 including a nozzle 651, and a connection substrate 74 provided on the upper surface of the discharge head main body 45. The discharge head main body 45 and the connection substrate 74 are connected via the BtoB connector 75. Further, the connection substrate 74 is provided with FFC connectors 76 and 77. The other end of the cable 86 is detachably connected to the FFC connector 76 (an example of the “third connector”), and the other end of the cable 87 is freely attachable to the FFC connector 77 (an example of the “fourth connector”) Connected to As a result, each drive circuit board 30 and each discharge head 40 are electrically connected via the cables 86 and 87.

  The guide member 62 has a guide rail portion 63 extending in the scanning direction X at its lower front surface. The carriage 71 is supported movably in the scanning direction X by a guide rail portion 63 at a carriage support portion 64 provided at the lower part of the rear surface. That is, the carriage support portion 64 is slidably coupled to the guide rail portion 63 in the scanning direction X. That is, the carriage 71 reciprocates along the scanning direction X while being guided by the guide rail portion 63 of the guide member 62 in the carriage support portion 64 by the drive of the moving mechanism 61.

  As shown in FIG. 3, the maintenance unit 91 is provided adjacent to the second support unit 42 in the scanning direction X. The maintenance unit 91 includes a cap 92 for capping the space where each nozzle 651 is opened as a closed space by contacting the discharge head 40. Capping is performed to suppress drying of the ink in each nozzle 651 of the ejection head 40. Capping is an example of maintenance and is not limited to this.

2. Electrical Configuration of Liquid Ejection Device Here, the electrical configuration of the liquid ejection device 1 will be described with reference to FIG. FIG. 5 is a block diagram showing the electrical configuration of the liquid ejection device 1. As shown in FIG. 5, the liquid discharge apparatus 1 includes a power supply circuit board 10, a control circuit board 20, a plurality of drive circuit boards 30-1 to 30-n, and a plurality of discharge heads 40-1 to 40-n. .

  The plurality of drive circuit boards 30-1 to 30-n are all referred to as the drive circuit board 30 when the same configuration is provided and it is not necessary to distinguish them. The plurality of ejection heads 40-1 to 40-n are all referred to as the ejection head 40 if they have the same configuration and need not be distinguished. Further, in the present embodiment, the drive circuit boards 30-i (i = 1 to n) and the ejection heads 40-i are provided correspondingly.

  The power supply circuit board 10 is provided with a high voltage generation circuit 110. Also, the power supply circuit board 10 is electrically connected to the control circuit board 20 via the cable 65.

  The high voltage generation circuit 110 generates a voltage HVH which is a voltage signal of, for example, DC 42 V used in the liquid ejection device 1 based on a power supply voltage (for example, AC 100 V which is a commercial power supply) input from the outside of the liquid ejection device 1 Output to the control circuit board 20.

  Further, the power supply circuit board 10 transmits a signal input from a host computer outside the liquid discharge device 1 to the control circuit board 20. The power supply circuit board 10 is fixed to the liquid discharge device 1 together with the control unit 2 (see FIG. 1).

  The control circuit board 20 is provided with a control circuit 210, and is electrically connected to the drive circuit board 30 via a B to B connector 83.

  The control circuit 210 includes an ejection data generation circuit 211 and a drive data generation circuit 212, and when the host computer supplies various signals such as image data via the power supply circuit board 10, the drive circuit board 30 and the ejection head 40 generates and outputs various control signals and the like for controlling 40.

  Specifically, part of the signal input to the control circuit 210 is input to the ejection data generation circuit 211. Then, the ejection data generation circuit 211 generates plural types of control signals for controlling the ejection of the ink from the ejection unit 600 based on the input signal.

  Specifically, the ejection data generation circuit 211 controls a plurality of (n) print data signals SI1 to SIn for controlling which of the drive voltages COM-A and COM-B described later is selected, and the ejection portion. A plurality (n) of latch signals LAT1 to LATn for controlling the timing at which the ink is ejected from 600 and a plurality (n) of change signals CH are generated, and a plurality (n) of drive circuit substrates 30- Output to each of 1 to 30-n. At this time, the print data signal SIi, the latch signal LATi, and the change signal CHi are input to the drive circuit substrate 30-i. The signals for controlling the discharge input to the drive circuit substrate 30 are referred to as a print data signal SI, a latch signal LAT (an example of a “second signal”), and a change signal CH.

  Furthermore, the ejection data generation circuit 211 outputs the clock signal Sck in common to the plurality of drive circuit boards 30-1 to 30-n.

  In addition, part of the signal input to the control circuit 210 is input to the drive data generation circuit 212. The drive data generation circuit 212 generates 2n pieces of drive data dA1 to dAn and dB1 to dBn, which are digital data that is the source of the drive voltage for driving the ejection unit 600, based on the input signal. It outputs to each of the drive circuit boards 30-1 to 30-n. At this time, drive data dAi and dBi are input to the drive circuit board 30-i. The digital data that is the source of the drive voltage input to the drive circuit board 30 is referred to as drive data dA and dB.

  Here, the drive data dA1 to dAn and dB1 to dBn may be digital data obtained by analog / digital conversion of the waveform (drive waveform) of the drive voltage, or digital data indicating a difference with respect to the latest drive data. The drive data dA1 to dAn and dB1 to dBn may be digital data defining the correspondence between the length of each section having a constant slope and the slope in the drive waveform.

The control circuit board 20 is provided with a wiring pattern for branching the voltage HVH generated by the high voltage generation circuit 110, and outputs the voltage HVH to each of the plurality of drive circuit boards 30-1 to 30-n. That is, the control circuit board 20 also functions as a relay board for branching and transferring the voltage HVH.

  The control circuit 210 provided on the control circuit board 20 may be provided on the power supply circuit board 10. Specifically, the print data signals SI1 to SIn generated by the control circuit 210, the latch signals LAT1 to LATn, the change signals CH1 to CHn, and the drive data dA1 to dAn, dB1 to dBn are generated by the power supply circuit board 10 and cables It may be configured to be input to the control circuit board 20 via 65.

  Furthermore, various signals transferred from the power supply circuit board 10 to the control circuit board 20 via the cable 65 are a serial control signal in LVDS (Low Voltage Differential Signaling) transfer system, LVPECL (Low Voltage Positive Emitter Coupled Logic) transfer system, It may be a differential signal used in a CML (Current Mode Logic) transfer method or the like. At this time, the power supply circuit board 10 is provided with various signals to be transferred to the control circuit board 20 and a conversion circuit for converting into the differential signal, and the control circuit board 20 receives the differential input thereto. A recovery circuit is provided to recover the signal.

  Drive circuits 311 and 312 and a voltage generation circuit 320 are provided on the drive circuit substrate 30, and are electrically connected to the ejection head 40 via the cables 86 and 87.

  The drive data dA and the voltage HVH are input to the drive circuit 311. The drive circuit 311 generates a drive voltage COM-A (an example of a “first signal”) which is a voltage signal based on the input drive data dA and the voltage HVH, and outputs the drive voltage COM-A to the discharge head 40.

  The drive data dB and the voltage HVH are input to the drive circuit 312. The drive circuit 312 generates a drive voltage COM-B, which is a voltage signal, based on the input drive data dB and the voltage HVH, and outputs the drive voltage COM-B to the discharge head 40.

  Here, the drive circuits 311 and 312 may differ only in the input data and the output voltage signal, and may have the same circuit configuration.

  For example, if the drive data dA and dB are digital data obtained by analog / digital converting the waveforms of the drive voltages COM-A and COM-B, the drive circuits 311 and 312 perform digital / analog conversion on the drive data dA and dB, respectively. Then, based on the voltage HVH, class D amplification is performed to generate drive voltages COM-A and COM-B.

  Further, for example, if the drive data dA and dB are digital data defining the correspondence between the length of each section having a constant slope and the slope in the waveform of the drive voltages COM-A and COM-B, respectively, the drive circuit No. 311 and 312 respectively generate analog signals satisfying the correspondence relationship between the length of each section defined by the drive data dA and dB and the slope, and then perform class D amplification based on the voltage HVH to drive voltages COM-A and COM. Generate -B.

  The voltage generation circuit 320 generates a plurality of voltage signals of a plurality of voltage values based on the voltage HVH.

Specifically, the voltage generation circuit 320 generates a voltage VBS (for example, DC 6 V) supplied to the piezoelectric element 60 provided in the ejection head 40 as a voltage signal, and outputs the voltage VBS to the ejection head 40. Further, the plurality of voltage generation circuits 320 generate, as voltage signals, voltages VDD (for example, DC 3.3 V) for supplying power supply voltages of various configurations provided in the ejection head 40 and output the voltages to the ejection head 40. Further, the plurality of voltage generation circuits 320 generate, as voltage signals, voltages GVDD (for example, DC 7.5 V) for driving the amplifiers included in the class D amplification circuits included in the drive circuits 311 and 312. Output to 312. The plurality of voltage generation circuits 320 may generate a plurality of voltage signals other than those described above.

  Further, the drive circuit substrate 30 transfers the print data signal SI, the latch signal LAT, the change signal CH, and the clock signal Sck, which are input from the discharge data generation circuit 211, to the discharge head 40.

  The drive circuit board 30 and the ejection head 40 are electrically connected by a cable 86 and a cable 87. Among them, the cable 86 transfers the drive voltages COM-A and COM-B and the voltages VDD and VBS from the drive circuit board 30 to the ejection head 40, and the cable 86 transmits the print data signal SI, the latch signal LAT, and the change signal CH. And transfer the clock signal Sck.

  The ejection head 40 includes a plurality of ejection modules 500.

  Each of the plurality of ejection modules 500 includes a drive signal selection circuit 510 and a plurality of ejection units 600.

  The drive signal selection circuit 510 includes a selection control circuit 520 and a plurality of selection circuits 530. The drive signal selection circuit 510 is formed of, for example, an IC (Integrated Circuit), and operates with the voltage VDD.

  The selection control circuit 520 receives the print data signal SI, the latch signal LAT, the change signal CH, and the clock signal Sck.

  Selection control circuit 520 is a selection signal for controlling which of drive voltages COM-A and COM-B should be selected (or not selected at all) for each of a plurality of selection circuits 530. Is generated based on the print data signal SI, and is output based on the timing determined by the latch signal LAT and the change signal CH.

  The drive voltages COM-A and COM-B generated by the drive circuits 311 and 312 are input to the selection circuits 530, respectively. Then, according to the selection signal output from the selection control circuit 520, one of the input drive voltages COM-A and COM-B is selected and output to the corresponding ejection unit 600 as the drive voltage Vout. Then, the drive voltage Vout is applied to one end of the piezoelectric element 60.

  At this time, the voltage HVH is also input to the selection circuit 530. The selection circuit 530 selects the high-voltage drive voltages COM-A and COM-B amplified based on the voltage HVH in the drive circuits 311 and 312, and outputs the selected drive voltages as the drive voltage Vout. Therefore, selection circuit 530 more reliably selects drive voltages COM-A and COM-B by controlling which of drive voltages COM-A and COM-B is selected using voltage HVH. be able to.

  As described above, the drive signal selection circuit 510 selects the input drive voltages COM-A and COM-B, and supplies them to the piezoelectric element 60 as the drive voltage Vout. In other words, the drive signal selection circuit 510 controls the supply of the drive voltages COM-A and COM-B to the piezoelectric element 60.

  Each of the plurality of ejection units 600 includes a piezoelectric element 60, and is provided corresponding to each of the selection circuits 530. The drive voltage Vout output from the selection circuit 530 is applied to one end of the piezoelectric element 60, and the voltage VBS is applied to the other end. Then, the piezoelectric element 60 is displaced due to the potential difference between the drive voltage Vout and the voltage VBS, and the ink is ejected from the ejection unit 600 (nozzle 651) based on the displacement.

3. Configuration of Discharge Unit FIG. 6 is a view showing a schematic configuration corresponding to one discharge unit 600 of the discharge module 500. As shown in FIG. As shown in FIG. 6, the discharge module 500 includes a discharge part 600 and a reservoir 641.

  The reservoir 641 is provided for each color of ink, and the ink is introduced into the reservoir 641 from the supply port 661.

  The discharge unit 600 includes a piezoelectric element 60, a diaphragm 621, a cavity 631 functioning as a pressure chamber, and a nozzle 651. Among these, the diaphragm 621 is displaced (flexural vibration) by the piezoelectric element 60 provided on the upper surface in FIG. 6, and functions as a diaphragm that enlarges / reduces the internal volume of the cavity 631 filled with the ink. The nozzle 651 is an opening provided in the nozzle plate 632 and in communication with the cavity 631. The inside of the cavity 631 is filled with ink, and the displacement of the piezoelectric element 60 changes the internal volume. The nozzle 651 communicates with the cavity 631 and discharges the ink in the cavity 631 as an ink droplet in accordance with the change of the internal volume of the cavity 631.

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

  The piezoelectric element 60 is not limited to the structure shown in FIG. 6 and may be any type that can deform the piezoelectric element 60 to eject ink. Further, the piezoelectric element 60 is not limited to bending vibration, and may be configured to use so-called longitudinal vibration.

  Also, the piezoelectric element 60 is provided corresponding to the cavity 631 and the nozzle 651 in the ejection module 500, and is also provided corresponding to the selection circuit 530 (see FIG. 9) described later. For this reason, in the ejection module 500, a set of the piezoelectric element 60, the cavity 631, the nozzle 651, and the selection circuit 530 is provided for each nozzle 651.

4. Configuration of Drive Signal (Drive Voltage) As a method of forming dots on the medium M, there is a method (first method) of ejecting an ink droplet from the nozzle 651 once to form one dot. In addition, ink droplets can be ejected twice or more from the nozzle 651 in a unit period, one or more ink droplets ejected in the unit period are made to land, and the one or more ink droplets thus landed are combined to form one dot. There is a method (second method) of forming Furthermore, there is a method (third method) of forming two or more dots without combining two or more ink droplets.

In the present embodiment, the second method discharges the ink twice at most for one dot, “large dot”, “medium dot”, “small dot”, and “non-recording (no dot)”. The four gradations of In order to express these four gradations, in the present embodiment, two types of drive voltages COM-A and COM-B are prepared, and in each of them, a first half pattern and a second half pattern are provided in one cycle. Drive voltage COM-A in the first half and second half of one cycle
, COM-B according to the gradation to be expressed (or not selected) to be supplied to the piezoelectric element 60.

  FIG. 7 is a diagram showing waveforms of the drive voltages COM-A and COM-B. As shown in FIG. 7, the drive voltage COM-A is a latch after the rise of the change signal CH and the trapezoid waveform Adp1 arranged in a period T1 from the rise of the latch signal LAT to the rise of the change signal CH. A trapezoidal waveform Adp2 arranged in a period T2 until the signal LAT rises is a continuous waveform. A new dot is formed on the medium M for each period Ta, with a period consisting of the period T1 and the period T2 as the period Ta.

  In the present embodiment, the trapezoidal waveforms Adp1 and Adp2 have substantially the same waveform, and if each is supplied to one end of the piezoelectric element 60, a predetermined amount from the nozzle 651 corresponding to the piezoelectric element 60, Specifically, it is a waveform that causes each medium amount of ink to be ejected.

  The driving voltage COM-B is a waveform in which a trapezoidal waveform Bdp1 disposed in the period T1 and a trapezoidal waveform Bdp2 disposed in the period T2 are continuous. In the present embodiment, the trapezoidal waveforms Bdp1 and Bdp2 are waveforms different from each other. Among these, the trapezoidal waveform Bdp1 is a waveform for finely vibrating the ink in the vicinity of the opening of the nozzle 651 to prevent an increase in the viscosity of the ink. Therefore, even if the trapezoidal waveform Bdp1 is supplied to one end of the piezoelectric element 60, the ink droplet is not discharged from the nozzle 651 corresponding to the piezoelectric element 60. The trapezoidal waveform Bdp2 is a waveform different from the trapezoidal waveform Adp1 (Adp2). If the trapezoidal waveform Bdp2 is supplied to one end of the piezoelectric element 60, it is a waveform that causes the nozzle 651 corresponding to the piezoelectric element 60 to eject an amount of ink smaller than the predetermined amount.

  The voltage at the start timing of the trapezoidal waveforms Adp1, Adp2, Bdp1, and Bdp2 and the voltage at the end timing are common to the voltage Vc.

  FIG. 8 is a diagram showing a waveform of the drive voltage Vout corresponding to each of "large dot", "medium dot", "small dot" and "non-recording".

  As shown in FIG. 8, the drive voltage Vout corresponding to the “large dot” is a combination of a trapezoidal waveform Adp1 of the drive voltage COM-A in the period T1 and a trapezoidal waveform Adp2 of the drive voltage COM-A in the period T2. It is a waveform. When the drive voltage Vout is supplied to one end of the piezoelectric element 60, a medium amount of ink is ejected twice in a cycle Ta from the nozzle 651 corresponding to the piezoelectric element 60. Therefore, the respective inks land on the medium M and coalesce to form large dots.

  The drive voltage Vout corresponding to the “medium dot” is a waveform in which a trapezoidal waveform Adp1 of the drive voltage COM-A in the period T1 and a trapezoidal waveform Bdp2 of the drive voltage COM-B in the period T2 are continuous. When the drive voltage Vout is supplied to one end of the piezoelectric element 60, medium and small amounts of ink are separately discharged twice from the nozzles 651 corresponding to the piezoelectric element 60 in the period Ta. Therefore, the respective inks land and unite on the medium M, and medium dots are formed.

The drive voltage Vout corresponding to the “small dot” is the voltage Vc immediately before being held by the capacitive property of the piezoelectric element 60 in the period T1, and is a trapezoidal waveform Bdp2 of the drive voltage COM-B in the period T2. When the drive voltage Vout is supplied to one end of the piezoelectric element 60, a small amount of ink is ejected only in the period T2 from the nozzle 651 corresponding to the piezoelectric element 60 in the period Ta. Therefore, the ink lands on the medium M to form small dots.

  The drive voltage Vout corresponding to “non-recording” is a trapezoidal waveform Bdp1 of the drive voltage COM-B in the period T1, and the voltage Vc immediately before held by the capacitive property of the piezoelectric element 60 in the period T2. When the drive voltage Vout is supplied to one end of the piezoelectric element 60, the nozzle 651 corresponding to the piezoelectric element 60 only slightly vibrates in the period T2 in the period Ta, and the ink is not discharged. Therefore, the ink does not land on the medium M, and the dots are not formed.

5. Configuration of Drive Signal Selection Circuit FIG. 9 shows a configuration of drive signal selection circuit 510. Referring to FIG. As shown in FIG. 9, drive signal selection circuit 510 includes a selection control circuit 520 and a plurality of selection circuits 530.

  The selection control circuit 520 is supplied with the clock signal Sck, the print data signal SI, the latch signal LAT, and the change signal CH. In the selection control circuit 520, a set of a shift register (S / R) 222, a latch circuit 224, and a decoder 226 is provided corresponding to each of the piezoelectric elements 60 (nozzles 651). That is, the number of sets of shift register 222, latch circuit 224, and decoder 226 included in one drive signal selection circuit 510 is the same as the total number m of nozzles 651.

  The print data signal SI is used to select one of “large dot”, “medium dot”, “small dot” and “non-recording” for each of the m discharge units 600 (piezoelectric elements 60). This is a signal of 2 m bits in total including 2 bits of print data (SIH, SIL).

  The print data signal SI is a signal synchronized with the clock signal Sck, and is configured to temporarily hold every two bits of print data (SIH, SIL) included in the print data signal SI corresponding to the nozzle 651. Is the shift register 222.

  More specifically, the shift registers 222 having the number of stages corresponding to the piezoelectric element 60 (nozzles 651) are cascade-connected to each other, and the serially supplied print data signal SI is sequentially transferred to the subsequent stage according to the clock signal Sck. It has become.

  Note that, in order to distinguish the shift register 222, they are described as one stage, two stages,..., M stages in order from the upstream side to which the print data signal SI is supplied.

  Each of the m latch circuits 224 latches the 2-bit print data (SIH and SIL) held by each of the m shift registers 222 at the rising edge of the latch signal LAT.

  Each of m decoders 226 decodes 2-bit print data (SIH, SIL) latched by each of m latch circuits 224, and a period T1 defined by latch signal LAT and change signal CH. , T2 to output the selection signals Sa and Sb to define the selection in the selection circuit 530.

  FIG. 10 is a diagram showing the contents of decoding in the decoder 226. As shown in FIG. For example, when the latched 2-bit print data (SIH, SIL) is (1, 0), the decoder 226 sets the logic levels of the selection signals Sa and Sb to H and L levels in period T1, respectively. In this, it means that it outputs as L and H level respectively.

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

  The selection circuit 530 is provided corresponding to each of the piezoelectric elements 60 (nozzles 651). That is, the number of selection circuits 530 included in one drive signal selection circuit 510 is the same as the total number m of nozzles 651.

  FIG. 11 is a diagram showing the configuration of the selection circuit 530 corresponding to one piezoelectric element 60 (nozzle 651).

  As shown in FIG. 11, the selection circuit 530 includes inverters (NOT circuits) 232a and 232b and transfer gates 234a and 234b.

  The selection signal Sa from the decoder 226 is supplied to the non-circled positive control terminal at the transfer gate 234a, while being logically inverted by the inverter 232a and circled at the transfer gate 234a. Supplied to the end. Similarly, while the selection signal Sb is supplied to the positive control end of the transfer gate 234b, it is logically inverted by the inverter 232b and supplied to the negative control end of the transfer gate 234b.

  The drive voltage COM-A is supplied to the input terminal of the transfer gate 234a, and the drive voltage COM-B is supplied to the input terminal of the transfer gate 234b. The output terminals of the transfer gates 234 a and 234 b are commonly connected, and the drive voltage Vout is output to the discharge unit 600 through the common connection terminal.

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

  Next, the operation of the drive signal selection circuit 510 will be described with reference to FIG.

  The print data signal SI is serially supplied in synchronization with the clock signal Sck and sequentially transferred in the shift register 222 corresponding to the nozzle 651. Then, when the supply of the clock signal Sck is stopped, 2-bit print data (SIH, SIL) corresponding to the nozzle 651 is held in each of the shift registers 222. The print data signal SI is supplied in the order corresponding to the final m stages,..., Two stages and one stage of nozzles in the shift register 222.

  Here, when the latch signal LAT rises, each of the latch circuits 224 latches the 2-bit print data (SIH, SIL) held in the shift register 222 all at once. 12, LT1, LT2,..., LTm indicate 2-bit print data (SIH, SIL) latched by the latch circuit 224 corresponding to the shift register 222 of one stage, two stages,. There is.

  The decoder 226 shows the logic levels of the selection signals Sa and Sb in FIG. 10 in each of the periods T1 and T2 in accordance with the size of the dot defined by the latched 2-bit print data (SIH, SIL). Output with similar content.

That is, when the print data (SIH, SIL) is (1, 1) and the size of the large dot is defined, the decoder 226 sets the selection signals Sa and Sb to H and L levels in the period T1, and The H and L levels are also set at T2. Further, when the print data (SIH, SIL) is (1, 0) and the size of the medium dot is defined, the decoder 226 sets the selection signals Sa, Sb to H, L levels in the period T1, and L and H levels at T2. When the print data (SIH, SIL) is (0, 1) and the small dot size is defined, the decoder 226 sets the selection signals Sa, Sb to L, L levels in the period T 1, and L and H levels at T2. Further, when the print data (SIH, SIL) is (0, 0) and the non-recording is defined, the decoder 226 sets the selection signals Sa and Sb to L and H levels in the period T1, and in the period T2. L, L level.

  When print data (SIH, SIL) is (1, 1), selection circuit 530 selects drive voltage COM-A (trapezoidal waveform Adp1) because selection signals Sa, Sb are at H, L levels in period T1. Since Sa and Sb are at the H and L levels also in period T2, the drive voltage COM-A (trapezoidal waveform Adp2) is selected. As a result, a drive voltage Vout corresponding to the "large dot" shown in FIG. 8 is generated.

  When the print data (SIH, SIL) is (1, 0), the selection circuit 530 selects the drive voltage COM-A (trapezoidal waveform Adp1) since the selection signals Sa, Sb are H, L levels in the period T1. In the period T2, since Sa and Sb are at L and H levels, the driving voltage COM-B (trapezoidal waveform Bdp2) is selected. As a result, the drive voltage Vout corresponding to the “medium dot” shown in FIG. 8 is generated.

  Further, when print data (SIH, SIL) is (0, 1), selection circuit 530 has L and L levels of selection signals Sa and Sb in period T1, and therefore any of drive voltages COM-A and COM-B. Also, since Sa and Sb are at L and H levels in period T2, drive voltage COM-B (trapezoidal waveform Bdp2) is selected. As a result, the drive voltage Vout corresponding to the "small dot" shown in FIG. 8 is generated. At this time, since neither of the drive voltages COM-A and COM-B is selected in the period T1, one end of the piezoelectric element 60 is open, but the drive voltage Vout is the voltage immediately before due to the capacitive property of the piezoelectric element 60. It is held at Vc.

  Further, when print data (SIH, SIL) is (0, 0), selection circuit 530 selects drive voltage COM-B (trapezoidal waveform Bdp1) because selection signals Sa and Sb are at L and H levels in period T1. In the period T2, since the selection signals Sa and Sb are at L and L levels, neither of the drive voltages COM-A and COM-B is selected. As a result, the drive voltage Vout corresponding to “non-recording” shown in FIG. 8 is generated. Since neither drive voltage COM-A nor COM-B is selected in the period T2, one end of the piezoelectric element 60 is open, but the drive voltage Vout has a voltage Vc immediately before due to the capacitive property of the piezoelectric element 60. Will be held by

  Note that the drive voltages COM-A and COM-B which are voltage signals shown in FIGS. 7 and 12 are merely examples, and in practice they are prepared in advance according to the moving speed of the carriage 71, the nature of the medium M, etc. Various combinations of waveforms are used.

6. Configuration of Discharge Head Here, the configuration of the discharge head 40 in the present embodiment will be described with reference to FIG. 13 to FIG.

  FIG. 13 is an exploded perspective view of the discharge head 40. FIG. As shown in FIG. 13, the discharge head 40 includes a discharge head main body 45 and a connection substrate 74 provided on the upper side (upper side in FIG. 13) of the discharge head main body 45 in the vertical direction Z.

  The connection substrate 74 is provided with the FFC connectors 76 and 77 and the BtoB connector 75 as described above.

  The BtoB connector 75 is provided on the lower surface (lower in FIG. 13) of the connection substrate 74 in the vertical direction Z, and is connected to the discharge head main body 45.

  The FFC connectors 76 and 77 are surfaces different from the surface on which the BtoB connector 75 of the connection substrate 74 is provided, and are provided along the front-rear direction Y on the upper surface in the vertical direction Z. The other end of the cable 86 is detachably connected to the FFC connector 76, and the other end of the cable 87 is detachably connected to the FFC connector 77, whereby the drive circuit board 30 and the ejection head 40 are connected. Are electrically connected.

  The discharge head main body 45 includes a holder 21 and a cover member 27.

  On both sides of the holder 21 in the front-rear direction Y, flange portions 22 are provided integrally with the holder 21. The flange portion 22 is fixed to the carriage body 72 (see FIG. 2) by a screw or the like.

  The cover member 27 is provided above the holder 21 in the vertical direction Z. The cover member 27 protects an ink flow path (not shown) provided inside the discharge head 40 for introducing the ink into the nozzle 651. Further, an opening 28 through which the BtoB connector 75 connected to the connection substrate 74 is inserted is provided above the cover member 27 in the vertical direction Z.

  FIG. 14 is an exploded perspective view of the discharge head 40 as viewed from the lower side in the vertical direction Z (the surface on which the nozzles 651 are formed).

  As shown in FIG. 14, the holder 21 of the ejection head 40 is provided with a fixing plate 23, a reinforcing plate 24, and a plurality (four in the present embodiment) of ejection modules 500.

  The holder 21 is made of a conductive material, such as metal, having a strength greater than that of the fixing plate 23. In the lower surface of the holder 21 in the vertical direction Z, a housing portion 25 for housing the plurality of discharge modules 500 is provided.

  The accommodation portion 25 has a concave shape that opens downward in the vertical direction Z, and accommodates a plurality of ejection modules 500 (an example of “ejection module”) fixed by the fixing plate 23. At this time, the opening of the housing portion 25 is sealed by the fixing plate 23. That is, the discharge module 500 is accommodated in the space formed by the accommodation portion 25 and the fixing plate 23. Note that the storage unit 25 may be provided for each discharge module 500, or may be provided continuously across the plurality of discharge modules 500.

  A recess 26 having a concave shape to which the reinforcing plate 24 and the fixing plate 23 are fixed is provided on the surface of the holder 21 on which the housing portion 25 is provided. The reinforcing plate 24 and the fixing plate 23 are sequentially stacked on the bottom of the recess 26.

  The fixing plate 23 is formed of a plate-like member formed of a conductive material such as metal. Further, the fixing plate 23 is provided with an opening 23a penetrating in the vertical direction Z, which exposes the nozzle surface 651a on which the nozzle 651 of each ejection module 500 is provided. The openings 23 a are provided independently for each of the ejection modules 500. The fixing plate 23 is fixed to the side of the nozzle surface 651 a of the ejection module 500 at the periphery of the opening 23 a.

  The reinforcing plate 24 is preferably made of a material having a strength higher than that of the fixing plate 23. In the reinforcing plate 24, an opening 24 a having an inner diameter larger than the outer periphery of the discharge module 500 corresponding to the discharge module 500 joined to the fixing plate 23 is provided to penetrate in the vertical direction Z. The discharge module 500 inserted into the opening 24 a of the reinforcing plate 24 is joined to the fixing plate 23.

  The fixed plate 23 and the holder 21 are mutually pressed by a predetermined pressure and joined while being supported by a support (not shown).

  FIG. 15 is a view showing a nozzle formation surface on which the nozzles 651 of the ejection head 40 are formed.

  As shown in FIG. 15, the ejection modules 500 are arranged in a staggered manner on the lower surface of the holder 21 in the vertical direction Z. In the ejection module 500, nozzles 651 for ejecting ink are arranged in parallel along the front-rear direction Y. Further, in the ejection module 500, two nozzle rows in which the nozzles 651 are arranged in parallel in the front-rear direction Y are provided in the scanning direction X. The ejection module 500 is provided with 300 or more nozzles 651 per inch in parallel along the scanning direction X, and one ejection module 500 is provided with 600 or more nozzles 651. That is, the discharge head 40 in the present embodiment is provided with 2400 or more nozzles 651 (discharge part 600).

7. Relationship between Variation of Transfer Time of Signal Due to FFC Wiring Length and Ejection Accuracy As described above, in the liquid ejection device 1 of the present embodiment, the ejection head 40 has a large number of 2400 or more nozzles 651. Therefore, many signals according to the number of the nozzles 651 are supplied to the discharge head 40.

  The signal supplied to the ejection head 40 is a signal (driving voltage COM-A, COM-B, etc.) for driving the piezoelectric element 60 to eject ink from the nozzle 651, and the voltage value is 30 V or more And a plurality of control signals (print data signal SI, latch signal LAT, change signal CH, etc.) for controlling the application of the signal to the piezoelectric element 60, and a signal having a frequency of several tens of kHz (for example, 50 kHz). A signal having a voltage value of 1 V or less and a frequency of several MHz (for example, 24 MHz) and a constant voltage signal (voltage VBS, voltage VDD, etc.) having a voltage value of several V are included.

  That is, the discharge head 40 is supplied with various signals having different voltage values and frequencies.

  Therefore, in the liquid ejection apparatus 1 according to the present embodiment, various signals having different voltage values and frequencies supplied to the ejection head 40 are transmitted from the drive circuit board 30 using the two cables of the cable 86 and the cable 87. The transfer to the ejection head 40 reduces the interference between the signals.

  Specifically, the cable 86 transfers the drive voltages COM-A and COM-B and the voltages VDD and VBS, which are voltage signals of high voltage, from the drive circuit substrate 30 to the ejection head 40, and the cable 87 reduces the voltage The print data signal SI, the latch signal LAT, and the clock signal Sck, which are voltage signals, are transferred from the drive circuit substrate 30 to the ejection head 40.

  As a result, interference between the control signals (print data signal SI, latch signal LAT, change signal CH, etc.) with small voltage values and the drive voltages COM-A and COM-B with large voltage values is reduced.

  However, printing for controlling the application of the drive voltages COM-A and COM-B which are voltage signals supplied to the piezoelectric element 60 to drive the piezoelectric element 60 and the drive voltages COM-A and COM-B to the piezoelectric element 60 The data signal SI, the latch signal LAT, and the change signal CH are transferred by different cables 86 and 87. Therefore, the delay time of the drive voltages COM-A and COM-B transferred by the cable 86, and the delay time of the print data signal SI, the latch signal LAT, and the change signal CH transferred by the cable 87 may possibly occur. There is.

  Therefore, in the drive circuit substrate 30, the timing when the drive voltage COM-A and COM-B generated in synchronization with the latch signal LAT and the change signal CH are supplied to the ejection head 40 via the cable 86, and the drive circuit Print data signal SI which controls the timing of generation of drive voltages COM-A and COM-B in substrate 30 and controls the timing of selection of drive voltages COM-A and COM-B in discharge head 40, latch signal The timing at which the LAT and change signal CH are supplied to the discharge head 40 may vary.

  Here, the influence on the ejection characteristics when the timing variation occurs in the signal supplied to the ejection head 40 as described above will be described with reference to FIGS. 16 and 17. FIG. 16 and 17 will be described using the drive voltage Vout corresponding to the aforementioned "medium dot" (see FIG. 8) as an example.

  FIG. 16 is a diagram showing the drive voltage Vout, the latch signal LAT, and the change signal CH in the drive circuit substrate 30 when the drive voltage Vout corresponding to the “medium dot” shown in FIG. 8 is generated. In FIG. 16, drive voltages COM-A and COM-B corresponding to the drive voltage Vout corresponding to “medium dot” are shown by thick lines.

  As shown in FIG. 16, the drive voltages COM-A and COM-B generated by the drive circuits 311 and 312 provided on the drive circuit substrate 30 have periods T1 and T1 defined by the latch signal LAT and the change signal CH. It is generated in synchronization with the period T2. At this time, as described above, the drive voltage COM-A is selected in the period T1 and the drive voltage COM-B is selected in the period T2 as the drive voltage Vout corresponding to the "medium dot".

  FIG. 17 is a view showing an example of the drive voltage Vout supplied to the ejection head 40, the latch signal LAT, and the change signal CH when the drive voltage Vout corresponding to the “medium dot” shown in FIG. 8 is generated. is there. In FIG. 17, drive voltages COM-A and COM-B corresponding to the drive voltage Vout corresponding to “medium dot” are shown by thick lines. Further, in FIG. 17, the drive voltage Vout, the latch signal LAT, and the change signal CH corresponding to the “medium dot” in the drive circuit substrate 30 are indicated by broken lines.

  As shown in FIG. 17, the latch signal LAT input to the discharge head 40 and the change signal CH become signals delayed by time t 1 due to the impedance component of the cable 87. The drive voltages COM-A and COM-B input to the discharge head 40 are signals delayed by time t2 due to the impedance component of the cable 86. When the time t1 and the time t2 are different times (in the example shown in FIG. 17, t1> t2 but not limited thereto), the drive voltages COM-A and COM-B and the latch signal The timings supplied to the ejection head 40 vary between the LAT and the change signal CH.

As described above (see FIG. 12 and FIG. 16), the drive signal selection circuit 510 provided in the ejection head 40 sets the drive voltage COM − at the timing of period T1 and period T2 defined by the latch signal LAT and the change signal CH. Which one of A and COM-B to select (or
The drive voltage Vout is generated by controlling whether or not all of them should be deselected.

  The latch signal LAT and the change signal CH supplied to the drive signal selection circuit 510 provided in the ejection head 40 are signals whose transfer time is delayed by t1 with respect to the signal output from the drive circuit substrate 30. Therefore, the drive signal selection circuit 510 defines periods T1 'and T2' which are timings delayed by time t1 as periods corresponding to the period T1 and the period T2 defined in the drive circuit substrate 30.

  On the other hand, the drive voltages COM-A and COM-B supplied to the ejection head 40 are signals whose transfer time is delayed by t2 with respect to the signal output from the drive circuit board 30. Therefore, with respect to the periods T1 'and T2' defined by the drive signal selection circuit 510, a timing deviation corresponding to "time t1-time t2" occurs.

  As a result, as shown in FIG. 17, part of the drive voltage COM-A in the period T1 'may be missing, and part of the drive voltage COM-B in the period T2' may be missing. Therefore, the drive voltage Vout corresponding to the “medium dot” applied to the piezoelectric element 60 is a signal of a voltage waveform in which a part of the voltage signal supplied to the piezoelectric element 60 is missing. Therefore, the displacement of the piezoelectric element 60 displaced based on the drive voltage Vout may vary, and the ejection accuracy of the ejection unit 600 may be lowered.

  In addition, when a shift occurs in the timing of the signal transferred by each of the cable 86 and the cable 87, another case where part of the voltage waveforms of both the drive voltage COM-A and the drive voltage COM-B described above is dropped In addition, for example, part of the voltage waveform of either the drive voltage COM-A or the drive voltage COM-B is missing, and there is also a concern that the discharge accuracy may be reduced. In addition, residual vibration or the like of the drive voltage COM-A (COM-B) in the period T1 '(period T2') is superimposed on the drive voltage COM-A (COM-B) in the period T2 '(period T1') There is also a concern that the discharge accuracy may be reduced due to the occurrence of distortion.

  As described above, drive voltages COM-A and COM-B which are voltage signals supplied to the piezoelectric element 60 to drive the piezoelectric element 60 and application of the drive voltages COM-A and COM-B to the piezoelectric element 60 are performed. When the print data signal SI to be controlled, the latch signal LAT, and the change signal CH are transferred by different cables 86 and 87, the delay time of the signal transferred by the cable 86 and the signal transferred by the cable 87 It is necessary to reduce the difference between the delay time of

8. Signal Delay Reduction and Improvement of Ejection Accuracy The liquid ejection device 1 according to this embodiment has a configuration for reducing the difference between the delay time of the signal transferred by the cable 86 and the delay time of the signal transferred by the cable 87. Have. Here, a configuration for reducing the difference between the delay time of the signal transferred by the cable 86 and the delay time of the signal transferred by the cable 87 will be described with reference to FIGS. 18 and 19.

  FIG. 18 is a side view showing the connection between the drive circuit board 30 and the ejection head 40. As shown in FIG. FIG. 19 is a top view showing the connection between the drive circuit substrate 30 and the ejection head 40. As shown in FIG.

  As shown in FIGS. 18 and 19, in the liquid discharge device 1 according to the present embodiment, the lengths of the wiring length L1 of the cable 86 connecting the drive circuit board 30 and the discharge head 40 and the wiring length L2 of the cable 87 Are the same. As a result, variations in impedance components of the cables 86 and 87 are reduced, and variations in transfer time of signals transferred by the cables 86 and 87 are reduced. Therefore, the occurrence of timing variations in the latch signal LAT and the change signal CH supplied to the ejection head 40 and the drive voltages COM-A and COM-B is reduced.

  Specifically, the drive circuit board 30 (substrate) is provided with an FFC connector 84 (first connector) and an FFC connector 85 (second connector).

  Further, the ejection head 40 is provided with an FFC connector 76 (third connector) and an FFC connector 77 (fourth connector), which are located apart from the drive circuit board 30.

  The FFC connector 84 and the FFC connector 76 are electrically connected by the cable 86 (first cable), and the FFC connector 85 and the FFC connector 77 are connected by the cable 87 (second cable) having the same length as the cable 86. Electrically connected.

  In addition, "the same length" is not limited to the case of exactly the same length, but means that it is substantially the same length, and a length capable of obtaining an equivalent effect Is a concept that includes

  Taking the case where it can be regarded as identical if the error with respect to the standard value is taken as an example, the specified values of the lengths of the cable 86 and the cable 87 are 150 mm, and the cables 86 and 87 have a length of 30 to 300 mm. If a tolerance of ± 5 mm is allowed in the range, that the cables 86 and 87 are “same length” means that the respective lengths of the cables 86 and 87 include the range 145 mm to 155 mm. Do. In addition, when the specified value of the lengths of the cable 86 and the cable 87 is 150 mm and the tolerance of ± 5% of the cable 86 and the cable 87 is allowed, it is assumed that the cable 86 and the cable 87 are “same length”. Means that the length of each of the cable 86 and the cable 87 includes the range of 142.5 mm to 157.5 mm.

  As shown in FIGS. 18 and 19, the drive circuit board 30 includes FFC connectors 84 and 85. The FFC connectors 84 and 85 are provided along the vertical direction Z on the side of the discharge head 40 in the front-rear direction Y of the drive circuit substrate 30. At this time, the FFC connector 84 is provided farther from the ejection head 40 than the FFC connector 85 in the vertical direction Z. In other words, in the vertical direction Z, the distance between the FFC connector 84 and the ejection head 40 is larger than the distance between the FFC connector 85 and the ejection head 40.

  Further, FFC connectors 76 and 77 are provided on the connection substrate 74 of the ejection head 40. The FFC connectors 76 and 77 are provided side by side in the front-rear direction Y on the upper surface of the connection substrate 74 in the vertical direction Z. At this time, the FFC connector 77 is provided farther from the drive circuit board 30 than the FFC connector 76 in the front-rear direction Y. In other words, in the front-rear direction Y, the distance between the FFC connector 76 and the drive circuit board 30 is smaller than the distance between the FFC connector 77 and the drive circuit board 30.

  The FFC connector 84 and the FFC connector 76 are electrically connected by the cable 86, and the FFC connector 85 and the FFC connector 77 are electrically connected by the cable 87. The discharge head 40 is electrically connected.

As described above, the cable 86 includes the FFC connector 84 provided at a position away from the ejection head 40 in the drive circuit board 30 and the FFC connector 76 provided at a position near the drive circuit board 30 in the ejection head 40. Electrically connected to The cable 87 is electrically connected to the FFC connector 85 provided at a position close to the ejection head 40 in the drive circuit substrate 30 and the FFC connector 77 provided at a position distant from the drive circuit substrate 30 in the ejection head 40. Connected to That is, the cable 86 and the cable 87 electrically connect the drive circuit board 30 and the ejection head 40 in a state where they cross each other.

  By electrically connecting the cable 86 and the cable 87 in a state in which the cables 86 and 87 cross each other, it is possible to reduce the lengthening of the cables 86 and 87 compared to the case where the cables 86 and 87 do not cross each other. In addition, the wiring length L1 of the cable 86 and the wiring length L2 of the cable 87 can be made the same. Therefore, the impedance component of the cable 86 and the cable 87 is reduced, and the variation of the impedance component of the cable 86 and the cable 87 can also be reduced. Therefore, the delay time by the impedance component of cable 86 of drive voltages COM-A and COM-B transferred by cable 86, and the impedance component of cable 87 of latch signal LAT and change signal CH transferred by cable 87. Variations in delay time can be reduced.

  As a result, the variation in timing between the latch signal LAT and the change signal CH supplied to the ejection head 40 and the drive voltages COM-A and COM-B is reduced.

  Here, the wiring length L1 of the cable 86 is the middle point of the side where the cable 86 is connected to the FFC connector 84 (contact a1) and the middle point of the side where the cable 86 is connected to the FFC connector 76 (contact b1) And the length of a straight line connecting along the cable 86. The wiring length L2 of the cable 87 is the middle point (contact a2) of the side where the cable 87 is connected to the FFC connector 85, and the middle point (contact b2) of the side where the cable 87 is connected to the FFC connector 77. Is the length of a straight line connected along the cable 87.

  Furthermore, a distance a, which is the distance between the FFC connector 84 and the FFC connector 85 provided on the drive circuit board 30, and a distance b, the distance between the FFC connector 76 and the FFC connector 77 provided on the ejection head 40, are It is preferable that it becomes the same.

  Here, the distance a means that the FFC connector 84 is connected to the contact a1 on the FFC connector 84 side of the wiring length L1 and the contact a2 on the FFC connector 85 and the FFC connector 85 side of the wiring length L2 described above. And the point at which the point is connected. Further, the distance b is a point at which the FFC connector 76 is connected to the contact b1 on the side of the FFC connector 76 of the above wiring length L1, the FFC connector 77 and the contact b2 on the side of the FFC connector 77 of the above wiring length L2. Is the distance between

  In addition, it is not restricted when the distance of the distance a and the distance b is exactly the same as being provided so that "the distance is the same" of the above-mentioned distance a and the distance b, and the distance a and the distance This means that the distances to b are substantially the same, for example, the concept that an error with respect to a standard value is allowed.

  For example, manufacturing tolerances and mounting tolerances of the FFC connectors 76, 77, 84 and 85, connection errors of the cable 86 electrically connected to the FFC connectors 76 and 84, and tolerances to the standard values are acceptable. This is a concept that allows for tolerances and errors including a connection error and the like of the cable 86 electrically connected to the FFC connectors 76 and 84.

Thus, the distance a, which is the distance between the FFC connector 84 and the FFC connector 85, and the distance b, which is the distance between the FFC connector 76 and the FFC connector 77 provided on the ejection head 40, are made equal. This makes it possible to reduce the lengthening of the cable 86 and the cable 87. In addition, it is possible to make the wiring length L1 of the cable 86 and the wiring length L2 of the cable 87 the same. Therefore, the delay time by the impedance component of cable 86 of drive voltages COM-A and COM-B transferred by cable 86, and the impedance component of cable 87 of latch signal LAT and change signal CH transferred by cable 87. Variations in delay time can be further reduced.

  In the present embodiment, high voltage signals including the drive voltages COM-A and COM-B are transferred from the drive circuit substrate 30 to the ejection head 40 via the cable 86, and the latch signal LAT and the change signal CH are also transmitted. Although it has been described that a low voltage control signal including the signal is transferred from the drive circuit board 30 to the ejection head 40 via the cable 87, the present invention is not limited thereto.

  Although the drive circuit board 30 and the ejection head 40 are each provided with two connectors, and various signals are transferred via the two cables 86 and 87, the drive circuit board 30 and the ejection head 40 are described. Three or more connectors may be provided in each of 40, and various signals may be transferred via three or more cables.

  Further, in the liquid discharge device 1 according to the present embodiment, as shown in FIG. 19 (and FIG. 4), a plurality of sets of the drive circuit board 30, the discharge head 40, and the cables 86 and 87 are provided on the carriage. The plurality of drive circuit boards 30 and the ejection head 40 are supported by the carriage 71 at regular intervals along the scanning direction X.

  At this time, it is preferable that all of the plurality of cables 86 and 87 connecting the respective sets of the drive circuit board 30 and the ejection head 40 be configured to have the same length. Thereby, the variation in timing between the drive voltages COM-A and COM-B and the latch signal LAT and the change signal CH between each of a plurality of sets of the drive circuit board 30, the ejection head 40, and the cables 86 and 87 is also Reduced.

  Therefore, the variation in the discharge timing of the ink between the plurality of discharge heads 40 mounted on the carriage 71 is also reduced, and the discharge accuracy of the liquid discharge device 1 can be further improved.

  Further, generally, in the liquid discharge device 1, it is possible to form many dots at one time by lengthening the nozzle row, and high speed printing can be performed. Furthermore, by providing many ejection heads 40, it becomes possible to adopt many ink colors, and high definition of printing becomes possible.

  In the liquid discharge apparatus 1 according to this embodiment, as described above, the FFC connectors 84 and 85 provided on the drive circuit board 30 are arranged in parallel along the vertical direction Z, and the FFC provided on the discharge head 40 The connectors 76 and 77 are arranged in parallel along the longitudinal direction Y. Furthermore, as shown in FIG. 15, the discharge head 40 is provided with a nozzle row in which the nozzles 651 are arranged in parallel in the front-rear direction Y.

  Thus, the FFC connectors 76 and 77 provided in the ejection head 40 are arranged in parallel along the front-rear direction Y, which is also the direction in which the nozzle rows are formed, and the FFC connectors 84 provided in the drive circuit board 30. , 85 along the vertical direction Z, which is also the direction in which ink is ejected from the nozzles 651, makes it possible to lengthen the nozzle array provided in the ejection head 40, and further, the drive circuit board 30, It is reduced that the set of the ejection head 40 and the cables 86 and 87 becomes large in the scanning direction X. Therefore, the carriage 71 can be provided with a large number of ejection heads 40, which reduces the size of the carriage 71 and enables high-speed and high-definition printing.

9. Operation and Effect As described above, in the liquid discharge device 1 according to this embodiment, the cable electrically connecting the FFC connector 84 provided on the drive circuit board 30 and the FFC connector 77 provided on the discharge head 40 Since the lengths of the cable 86 electrically connecting the FFC connector 85 provided on the drive circuit substrate 30 and the FFC connector 77 provided on the ejection head 40 are the same, the cable 86 and the cable 87 And variations in their respective impedance components are reduced. Therefore, delay times of signals generated in drive voltages COM-A and COM-B transferred through cable 86, and delay times of signals generated in latch signal LAT and change signal CH transferred through cable 87. The variation of and can be reduced. For this reason, the variation in the timing between the drive voltages COM-A and COM-B supplied to the ejection head 40, the latch signal LAT, and the change signal CH is reduced, and the ejection accuracy of the liquid ejection device 1 can be improved. it can.

  Further, in the liquid discharge apparatus 1 according to the present embodiment, even when the plurality of drive circuit boards 30 and the plurality of discharge heads 40 corresponding to the plurality of drive circuit boards 30 are provided, the discharge head 40 is provided. Since the FFC connectors 76 and 77 are provided side by side in the front-rear direction Y (nozzle array direction), the enlargement of the carriage 71 on which the plurality of drive circuit boards 30 and the ejection head 40 are mounted is reduced. It becomes possible.

  As mentioned above, although an embodiment and a modification were described, the present invention is not limited to these embodiments, and can be carried out in various modes in the range which does not deviate from the gist. For example, the above embodiments can be combined as appropriate.

  The invention includes configurations substantially the same as the configurations described in the embodiments (for example, configurations having the same function, method and result, or configurations having the same purpose and effect). The present invention also includes configurations in which nonessential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that can achieve the same effects or the same objects as the configurations described in the embodiments. Further, the present 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, 2 ... control part, 3 ... delivery part, 4 ... support part, 5 ... conveyance part, 6 ... printing part, 10 ... power supply circuit board, 20 ... control circuit board, 21 ... holder, 22 ... flange Parts 23 Fixing plates 23a, 24a Openings 24 Reinforcing plates 25 Housings 26 26 Recesses 27 Covering members 28 Openings 29 Connectors 30 Driving circuit board 30-1 Drive circuit board 31... Holding member 40. Discharge head 41. First support part 42. Second support part 43. Third support part 45 Discharge head main body 51 Rotating mechanism 52 Transport roller , 53: driven roller, 60: piezoelectric element, 61: moving mechanism, 62: guide member, 63: guide rail portion, 64: carriage support portion, 65: cable, 71: carriage, 72: carriage main body, 73: carriage cover , 74 Connection board, 75, 83 ... B to B connector, 76, 77, 84, 85 ... FFC connector, 81 ... heat radiation case, 86, 87 ... cable, 91 ... maintenance part, 92 ... cap, 110 ... high voltage generation circuit, 210 ... Control circuit 211 Discharge data generation circuit 212 Drive data generation circuit 222 Shift register 224 Latch circuit 226 Decoder 232a, 232b Inverter 234a, 234b Transfer gate 311, 312 Drive circuit , 320: voltage generation circuit, 500: discharge module, 510: drive signal selection circuit, 520: selection control circuit, 530: selection circuit, 600: discharge part, 601: piezoelectric body, 611, 612, electrode, 621: diaphragm , 631 ... cavity, 632 ... nozzle plate, 641 ... Observers, 651 ... nozzle, 651a ... nozzle face 661 ... supply port, F ... conveying direction, L1 ... wiring length, L2 ... wiring length, M ... medium, R ... roll

Claims (6)

A substrate provided with a first connector and a second connector;
A third connector to which a first signal is transferred, a fourth connector provided parallel to the third connector in a first direction and to which a second signal is transferred, and a plurality of nozzles from which liquid is discharged; A discharge head provided spaced apart from the substrate in the first direction;
A first cable electrically connecting the first connector and the third connector;
A second cable that electrically connects the second connector and the fourth connector and has the same length as the first cable;
A liquid discharge apparatus characterized by comprising: In a second direction intersecting the first direction, the first connector and the second connector are provided side by side,
The distance between the first connector and the second connector in the second direction is the same as the distance between the third connector and the fourth connector in the first direction,
The liquid discharge device according to claim 1, The distance between the first connector and the discharge head in the second direction is greater than the distance between the second connector and the discharge head,
The distance between the third connector and the substrate in the first direction is smaller than the distance between the fourth connector and the substrate.
The liquid discharge device according to claim 2, A plurality of the substrate, the ejection head, the first cable, and the second cable are provided in a third direction intersecting the first direction and the second direction.
The liquid discharge apparatus according to claim 2 or 3, wherein The discharge head is provided with a plurality of discharge modules provided with 300 or more and 600 or more nozzles per inch.
The liquid discharge device according to any one of claims 1 to 4, characterized in that: A substrate provided with a first connector and a second connector;
A third connector to which a first signal is transferred, a fourth connector provided parallel to the third connector in a first direction and to which a second signal is transferred, and a plurality of nozzles from which liquid is discharged; A discharge head provided spaced apart from the substrate in the first direction;
A first cable electrically connecting the first connector and the third connector;
A second cable electrically connecting the second connector and the fourth connector;
Have
The first connector and the second connector are provided side by side in a second direction in which the liquid is discharged from the nozzle.
The first connector is provided farther from the discharge head than the second connector in the second direction,
The fourth connector is provided farther from the substrate than the third connector in the first direction,
The distance between the first connector and the second connector in the second direction is the same as the distance between the third connector and the fourth connector in the first direction,
Liquid discharge device characterized by.

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