JP2018199313A - Liquid discharge device and cable - Google Patents

Abstract

A liquid ejecting apparatus capable of reducing the interference of signals transferred by a cable and accurately ejecting a liquid. A discharge unit in which a first drive signal and a second drive signal are exclusively applied to one end of a drive element and a constant voltage signal is applied to the other end of the drive element, a first drive signal, and a second drive signal A drive circuit unit that outputs a double drive signal including a drive signal; and a cable that transfers the first drive signal, the second drive signal, and the constant voltage signal to the discharge unit. Including a first conductor group to which any one of the two drive signals is applied and a second conductor group to which a constant voltage signal is applied. The first conductor group includes the first conductor to which the first drive signal is applied and the second conductor group. A second conductor to which a driving signal is applied, a second conductor group having a third conductor to which a constant voltage signal is applied, the third conductor being positioned adjacent to the first conductor, and a third conductor The conductor is located adjacent to the second conductor, and the number of conductors included in the second conductor group is the first conductor group. Less than the number of conductors included. [Selection] Figure 14

Description

  The present invention relates to a liquid ejection device and a cable.

  2. Related Art An ink jet printer (liquid ejecting apparatus) that ejects ink to print an image or a document uses a piezoelectric element (for example, a piezo element). The piezoelectric element is provided corresponding to each of the plurality of nozzles in the head (print head), and each is driven according to a drive signal. The nozzle ejects a predetermined amount of ink (liquid) at a predetermined timing when the piezoelectric element is driven to form dots. Since the piezoelectric element is a capacitive load such as a capacitor when viewed electrically, it is necessary to supply a sufficient current to operate the piezoelectric element of each nozzle. For this reason, the above-described ink jet printer has a configuration in which the drive circuit supplies a high voltage drive signal amplified by the amplification circuit to the head to drive the piezoelectric element.

  By the way, in the above-described ink jet printer, a drive signal for driving the piezoelectric element is transferred from the drive circuit to the head via a cable. In an inkjet printer having a cable for transferring such a drive signal, crosstalk (signal interference) may occur in the cable, and the drive signal may be distorted. At this time, the amount of ink ejected from the nozzles may change slightly due to distortion generated in the drive signal, and print quality may be impaired. For this reason, in an ink jet printer that transfers a drive signal to a head via a cable, it is important that the drive signal is transferred to the head without distortion in the cable and applied to the piezoelectric element.

  Patent Document 1 discloses a wiring layout for reducing signal interference in a flexible flat cable used in an ink jet printer, which is provided with a plurality of drive signal wirings and ground wirings. .

JP 2003-226006 A

  However, in the wiring layout of the flexible flat cable disclosed in Patent Document 1 and used for an ink jet printer, signal interference may not be sufficiently reduced depending on the type of transfer drive signal and the transfer timing. There was room.

  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 interference of signals transferred through a cable, and to accurately discharge a liquid. It is possible to provide a liquid ejection device and a cable that can be used.

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

[Application Example 1]
The liquid ejection apparatus according to this application example includes a drive element, the first drive signal and the second drive signal are exclusively applied to one end of the drive element, and a constant voltage signal is applied to the other end of the drive element. A discharge unit including a discharge unit that drives the drive element to discharge liquid by being applied; and a drive circuit unit that outputs a plurality of drive signals including the first drive signal and the second drive signal; A cable for transferring the first drive signal, the second drive signal, and the constant voltage signal to the discharge unit, wherein the cable is one of the first drive signal and the second drive signal. A first conductor group composed of a plurality of conductors to be applied; and a second conductor group composed of one or a plurality of conductors to which the constant voltage signal is applied, wherein the first conductor group receives the first drive signal. Applied first conductor and second drive A second conductor to which a signal is applied, the second conductor group has a third conductor to which the constant voltage signal is applied, and the third conductor is located adjacent to the first conductor; The third conductor is located adjacent to the second conductor, and the number of conductors included in the second conductor group is less than the number of conductors included in the first conductor group.

  The “driving element” may be, for example, a piezoelectric element or a heat generating element.

  In the liquid ejection apparatus according to this application example, when the first drive signal is applied to one end of the drive element, there is a path through which current flows in the order of the first conductor, the drive element, and the third conductor. That is, the current flowing through the first conductor and the current flowing through the third conductor located adjacent to the first conductor flow in opposite directions in the cable. As a result, the magnetic field generated by the current flowing through the first conductor and the magnetic field generated by the current flowing through the third conductor cancel each other. Therefore, the mutual interference between the first drive signal applied to the first conductor and the constant voltage signal applied to the third conductor is reduced. Similarly, when a second drive signal is applied to one end of the drive element, there is a path through which current flows in the order of the second conductor, the drive element, and the third conductor. That is, the current flowing in the second conductor and the current flowing in the third conductor located adjacent to the second conductor flow in opposite directions in the cable. Thereby, the magnetic field generated by the current flowing through the second conductor and the magnetic field generated by the current flowing through the third conductor cancel each other. Therefore, the mutual interference between the second drive signal applied to the second conductor and the constant voltage signal applied to the third conductor is reduced. In the liquid ejection device according to this application example, in the cable, the third conductor is located adjacent to both the first conductor and the second conductor, and therefore, the first drive signal and the second drive signal are transmitted to one end of the drive element. Regardless of which is applied, it is possible to reduce the mutual interference of signals transferred through the cable. Therefore, according to the liquid discharge apparatus according to this application example, it is possible to discharge liquid with high accuracy.

  In the liquid ejection device according to this application example, in the cable, the one or more conductors to which the constant voltage signal is applied are between the plurality of conductors to which either the first drive signal or the second drive signal is applied. Should be provided next to each other. Therefore, the number of one or more conductors (second conductor group) to which a constant voltage signal is applied is equal to the plurality of conductors (first conductor group) to which either the first drive signal or the second drive signal is applied. The number can be less. As a result, the cost of the cable connecting the discharge unit and the drive circuit unit can be reduced.

[Application Example 2]
In the liquid ejection apparatus according to the application example, the first conductor group includes a fourth conductor to which the first drive signal is applied, and the second conductor group includes a fifth conductor to which the constant voltage signal is applied. The fifth conductor may be positioned adjacent to the second conductor, and the fifth conductor may be positioned adjacent to the fourth conductor.

According to the liquid ejection apparatus according to this application example, the first drive signal is also applied to the fourth conductor. Therefore, the amount of current flowing per conductor to which the first drive signal is applied is reduced, and the magnetic field generated for each conductor to which the first drive signal is applied can be reduced. A constant voltage signal is also applied to the fifth conductor. Therefore, the amount of current flowing per conductor to which a constant voltage signal is applied is reduced, and the magnetic field generated for each conductor to which a constant voltage signal is applied can be reduced. Therefore, it is possible to further reduce the mutual interference between the signals of the conductors to which the first voltage signal and the constant voltage signal are applied.

  Further, according to the liquid ejection apparatus according to this application example, the conductor to which the first drive signal is applied and the conductor to which the second drive signal is applied are alternately positioned in the cable. Further, the conductor to which the constant voltage signal is applied is located adjacent to the conductor to which the first drive signal is alternately applied and the conductor to which the second drive signal is applied. Therefore, even in a cable having a plurality of conductors to which the first drive signal is applied and conductors to which the constant voltage signal is applied, it is possible to reduce mutual interference between signals transferred through the cable. Therefore, according to the liquid ejection apparatus according to this application example, it is possible to eject the liquid with higher accuracy.

[Application Example 3]
In the liquid ejection device according to the application example, one or a plurality of conductors included in the second conductor group may be electrically connected in the ejection unit.

  According to the liquid ejection device according to this application example, the one or more conductors included in the second conductor group are electrically connected on the ejection unit side including the ejection unit, and thus a constant voltage signal is applied. The current flowing through the conductors flows substantially evenly through the plurality of conductors included in the second conductor group. That is, the current flowing through the second conductor group has small variations among the plurality of conductors included in the second conductor group regardless of variations in the characteristics of the first drive signal and the second drive signal. For this reason, the magnetic field generated by the current flowing through the first conductor group and the magnetic field generated by the current flowing through the second conductor group can be canceled more accurately, and mutual interference between signals transferred by the cable can be reduced. It becomes possible to reduce in a wide area. Therefore, according to the liquid ejection apparatus according to this application example, it is possible to eject the liquid with higher accuracy.

[Application Example 4]
In the liquid ejection device according to the application example, in the cable, any of the plurality of conductors included in the first conductor group may be any one or more of the conductors included in the second conductor group. Any one of the plurality of conductors included in the first conductor group located on the first end side of the cable is different from the one or the plurality of conductors included in the second conductor group. It may be located on the second end side of the cable.

  According to the liquid ejection apparatus according to this application example, in the cable, the cable includes both ends (first end) of the plurality of conductors included in the first conductor group and one or more conductors included in the second conductor group. Each of the conductors included in the first conductor group is located on each of the first and second end portions. In other words, at least one conductor included in the first conductor group is located on each of both ends of the cable of one or more conductors included in the second conductor group. As a result, the conductors included in the first conductor group can be positioned on both sides of the conductors included in the second conductor group. Therefore, the magnetic field generated by the current flowing through the second conductor group can be canceled by the magnetic field generated by the current flowing through the first conductor group in a wide range of the cable. Therefore, the liquid ejection device can reduce the mutual interference of signals transferred by the cable in a wide area of the cable, and can eject the liquid with higher accuracy.

[Application Example 5]
In the liquid ejection device according to the application example described above, the number of conductors included in the second conductor group may be one less than the number of conductors included in the first conductor group.

According to the liquid ejection device according to this application example, it is possible to position either one or a plurality of conductors included in the second conductor group between each of the plurality of conductors included in the first conductor group. Become. Therefore, the magnetic field generated by the current flowing through the first conductor group and the magnetic field generated by the current flowing through the second conductor group can be canceled out efficiently. Thereby, it becomes possible to reduce the mutual interference of the signals transferred by the cable over a wide area of the cable, and according to the liquid ejection device according to this application example, it becomes possible to eject the liquid with higher accuracy. .

[Application Example 6]
In the liquid ejection device according to the application example, the waveform of the first drive signal may be different from the waveform of the second drive signal.

  According to the liquid ejection apparatus according to this application example, even if one of the first drive signal and the second drive signal is applied to one end of the drive element, the mutual interference of signals due to the magnetic field generated by the current flowing in the cable conductor is reduced. Can be reduced. Therefore, even if the waveforms of the first drive signal and the second drive signal are different from each other, it is possible to reduce the mutual interference of the signals transferred by the cable. Therefore, according to the liquid discharge apparatus according to this application example, it is possible to discharge liquid with high accuracy.

[Application Example 7]
In the liquid ejection apparatus according to the application example described above, it may be possible to perform serial printing on a medium having an A3 short side width or more.

  “Serial printing” is a printing method in which the print head unit moves to perform printing.

  In a liquid ejection device that performs serial printing on a medium with an A3 short side or longer, the print head moves and performs printing, so the length of the cable transferred to the ejection unit becomes longer and the inductance component of the cable increases. To do. Therefore, problems such as overshoot and undershoot of the drive signal due to the inductance component of the cable, and a voltage drop of the drive signal may occur.

  According to the liquid ejection apparatus according to this application example, it is possible to efficiently cancel the magnetic field generated by the current flowing through the first conductor group and the magnetic field generated by the current flowing through the second conductor group. That is, the inductance component of the cable including the first conductor group and the second conductor group is reduced. Therefore, in a liquid ejection apparatus that performs serial printing on a medium having a short side width of A3 or longer where the cable wiring length is long, overshoot and undershoot of the drive signal due to the inductance component of the cable, voltage drop of the drive signal, etc. This problem can be solved.

[Application Example 8]
In the liquid ejection device according to the application example described above, a maximum width in which the serial printing is possible may be 24 inches or more and 75 inches or less.
When the maximum width capable of serial printing is 24 inches or more and 75 inches or less, the total length of the signal line to which the drive signal is transferred can be about 1 m to 3 m, so that the impedance and inductance of the signal line are increased. Therefore, according to the liquid ejection device according to this application example, the effect of reducing the inductance of the cable is greater. If the maximum width that can be printed serially exceeds 75 inches, the impedance and inductance of the signal line to which the drive signal is transferred become too large, causing overshoot and undershoot of the drive signal, voltage drop of the drive signal, etc. Since there is a greater risk of the occurrence, the above effect is difficult to obtain.

[Application Example 9]
In the liquid ejection device according to the application example described above, the maximum width capable of serial printing may correspond to any of 24 inches, 36 inches, 44 inches, and 64 inches.
According to the liquid ejecting apparatus according to this application example, it is excellent as a liquid ejecting apparatus for 24 inches, a liquid ejecting apparatus for 36 inches, a liquid ejecting apparatus for 44 inches, or a liquid ejecting apparatus for 64 inches. Printing accuracy and printing stability can be realized.

[Application Example 10]
The cable according to this application example outputs a plurality of drive signals including a discharge unit including a discharge unit that discharges liquid by driving a drive element, and a first drive signal and a second drive signal for driving the drive element. In the liquid ejection device including a drive circuit unit, a cable for transferring the first drive signal, the second drive signal, and the constant voltage signal to the ejection unit, the first drive signal and the second drive signal unit A first conductor group composed of a plurality of conductors to which any one of the drive signals is applied; and a second conductor group composed of one or a plurality of conductors to which the constant voltage signal is applied, the first conductor group Includes a first conductor to which the first drive signal is applied and a second conductor to which the second drive signal is applied, and the second conductor group includes a third conductor to which the constant voltage signal is applied. The third conductor includes a front The third conductor is positioned adjacent to the second conductor, the third conductor is positioned adjacent to the second conductor, and the number of conductors included in the second conductor group is the number of conductors included in the first conductor group. Less than the number.

  In the cable according to this application example, in the liquid ejection device, the first conductor group to which the first drive signal applied to one end of the drive element is applied, the second conductor to which the second drive signal is applied, and the other drive elements. A third conductor to which a constant voltage applied to the end is applied is positioned adjacent to the first conductor, the third conductor, and the second conductor in this order. At this time, when the first drive signal is applied to one end of the drive element, there is a path through which current flows in the order of the first conductor, the drive element, and the third conductor. At this time, the current flowing through the first conductor and the current flowing through the third conductor flow in opposite directions in the cable. Further, when the second drive signal is applied to one end of the drive element, there is a path through which current flows in the order of the second conductor, the drive element, and the third conductor. At this time, the current flowing through the second conductor and the current flowing through the third conductor flow in opposite directions in the cable. That is, the current flowing through the first conductor and the second conductor and the current flowing through the third conductor flow in opposite directions in the cable. Therefore, the magnetic field generated by the current flowing through the first conductor or the second conductor is canceled by the magnetic field generated by the current flowing through the third conductor. Therefore, it is possible to reduce the mutual interference of signals transferred by the cable. Therefore, according to the liquid ejecting apparatus including the cable according to this application example, it is possible to eject liquid with high accuracy.

  In the cable according to this application example, the one or more conductors to which the constant voltage signal is applied are adjacent to each other between the plurality of conductors to which either the first drive signal or the second drive signal is applied. It only has to be provided. Therefore, the number of one or more conductors (second conductor group) to which a constant voltage signal is applied is equal to the plurality of conductors (first conductor group) to which either the first drive signal or the second drive signal is applied. The number can be less. As a result, it is possible to reduce the cost of the cable used in the liquid ejection device and connecting the ejection unit and the drive circuit unit.

It is an external appearance schematic diagram which shows the 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 schematic structure of a discharge part. It is a figure which shows an example of the nozzle arrangement | sequence contained in a discharge part. FIG. 5 is a diagram for explaining a basic resolution of image formation by the nozzle arrangement shown in FIG. 4. It is a figure which shows an example of the waveform of drive signal COM-Ai and COM-Bi. It is a figure which shows an example of the waveform of the drive signal Vout. It is a figure which shows the structure of a selection circuit. It is a figure which shows the decoding content of a decoder. It is a figure which shows the structure of a selection part. It is a figure for demonstrating operation | movement of a selection control part and a selection part. It is a figure which shows schematically the internal structure of a liquid discharge apparatus. It is the schematic which shows the structure of the cable 193 in 1st Embodiment. It is a figure which shows the signal structure transferred with the cable 193 in 1st Embodiment. It is a figure for demonstrating the electric current path | route when the drive signal COM-A is applied to the end of the drive element in 1st Embodiment. It is a figure for demonstrating the electric current path | route when the drive signal COM-B is applied to the end of the drive element in 1st Embodiment. It is the schematic which shows the structure of the cable 193 in 2nd Embodiment. It is a figure which shows the signal structure transferred with the cable 193 in 2nd Embodiment. It is a figure for demonstrating the electric current path | route when the drive signal COM-A is applied to the end of the drive element in 2nd Embodiment. It is a figure for demonstrating the electric current path | route when the drive signal COM-B is applied to the end of the drive element 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. 1. First Embodiment 1.1 Outline of Liquid Ejecting Apparatus A printing apparatus as an example of a liquid ejecting apparatus according to a first 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.

  FIG. 1 is a schematic external view of the liquid ejection apparatus 1. As shown in FIG. 1, the liquid ejection device 1 is a serial scan type (serial printing type) large format printer, and includes a main body 2 and a support stand 3 that supports the main body 2. The large format printer is, for example, a printer corresponding to a paper size in which the size of the printable print medium P is A3 short side width (297 mm × 420 mm) or more, and the large format printer in the first embodiment is capable of printing. This is a so-called large format printer (LFP) in which the maximum size of the print medium P is about 75 inches. In the first embodiment, in FIG. 1, the movement direction of the carriage 24 provided in the liquid ejection device 1 is the main scanning direction X, the transport direction of the printing medium P of the liquid ejection device 1 is the sub-scanning direction Y, and the liquid ejection The vertical direction of the apparatus 1 will be described as the vertical direction Z. Further, although the main scanning direction X, the sub-scanning direction Y, and the vertical direction Z are illustrated in the drawing as three axes of X, Y, and Z that are orthogonal to each other, the arrangement relationship of each component is not necessarily orthogonal. Is not to be done.

  As shown in FIG. 1, the main body 2 includes a supply unit 4 that supplies a printing medium (roll paper) P, a printing unit 5 that discharges ink droplets to the printing medium P, and performs printing on the printing medium P. A discharge unit 6 that discharges the printing medium P printed by the unit 5 to the outside of the main body 2, an operation unit 7 that performs operations such as execution and stop of printing, and ink that stores discharged ink (liquid) And a storage unit 8. Although not shown, a USB port and a power port are disposed on the rear surface of the liquid ejection apparatus 1. That is, the liquid ejection device 1 is configured to be connectable to a computer or the like via a USB port.

The printing unit 5 includes a carriage 24, a head 21 mounted on the carriage 24 so as to face the print medium (roll paper) P, a carriage guide shaft 32, and an ink tube 9.

  The head 21 is a liquid ejecting head for ejecting ink droplets (droplets) from a large number of nozzles. The carriage 24 is supported by the carriage guide shaft 32 and moves (reciprocates) in the main scanning direction X. At this time, the print medium P is conveyed in the sub-scanning direction Y. That is, the liquid ejection apparatus 1 according to the first embodiment performs serial printing in which a carriage 24 equipped with a head 21 that ejects ink droplets (liquid) moves (reciprocates) in the main scanning direction X to perform printing.

  A plurality of ink cartridges are attached to the ink reservoir 8 and each ink cartridge is filled with a corresponding color ink. The ink cartridge shown in FIG. 1 shows four ink cartridges corresponding to four colors of C (cyan), M (magenta), Y (yellow), and B (black). For example, four or more ink cartridges may be provided, and ink cartridges of different colors such as gray, green, and violet may be included. The ink stored in each ink cartridge is supplied to the head 21 through the ink tube 9.

1.2 Electrical Configuration of Liquid Ejecting Device FIG. 2 is a block diagram showing an electrical configuration of the liquid ejecting device 1 of the first embodiment.

  As shown in FIG. 2, the liquid ejection apparatus 1 generates a drive signal for driving the ejection unit 600 that ejects liquid based on a control unit 10 that controls ejection of the liquid and a signal from the control unit 10. The drive circuit unit 30 and a plurality of discharge units 20 including a discharge unit 600 that discharges liquid to the print medium P are included.

  The control unit 10 includes a control signal generation unit 100, a control signal conversion unit 110, a control signal transmission unit 120, and a drive data transmission unit 140.

  When various signals such as image data are supplied from the host computer, the control signal generation unit 100 outputs various control signals for controlling each unit. Specifically, the control signal generation unit 100 generates a control signal for controlling the carriage moving mechanism 41 and a control signal for controlling the paper transport mechanism 42. The carriage moving mechanism 41 moves (reciprocates) the carriage 24 in the main scanning direction X, for example, by controlling the rotation of a motor for moving the carriage 24. Further, the paper transport mechanism 42 rotatably supports a continuous print medium P wound in a roll shape, for example, and transports the print medium P by rotation. That is. The carriage moving mechanism 41 and the paper transport mechanism 42 operate based on a control signal from the control signal generation unit 100, thereby enabling printing at a predetermined position on the print medium P.

  In addition, the control signal generation unit 100 generates a control signal for causing the maintenance mechanism 80 to perform maintenance processing for recovering the ink ejection state in the ejection unit 600 normally. Based on the control signal from the control signal generator 100, the maintenance mechanism 80 performs a cleaning process (pumping process) for sucking thickened ink, bubbles, and the like in the ejection unit 600 with a tube pump (not shown) as a maintenance process. Then, a wiping process of wiping off foreign matters such as paper dust adhering to the vicinity of the nozzle of the discharge unit 600 with a wiper is performed.

The control signal generation unit 100 also includes a plurality of original clock signals sSck (sSck1 to sSckn) as a plurality of types of original control signals for controlling the liquid ejection from the ejection unit 600 based on various signals from the host computer. A plurality of original print data signals sSI (sSI1 to sSIn), a plurality of original latch signals sLAT (sLAT1 to sLATn), and a plurality of original change signals sCH (sCH1 to sCHn) are generated, and the control signal conversion unit 110 is generated in parallel format.
Output to. Note that the plurality of types of original control signals may not include some of these signals, or may include other signals.

  Further, the control signal generation unit 100, based on various signals from the host computer, includes a plurality of original drive data sdA (sdA1 to sdAn) and sdB (data indicating drive signals for driving the ejection unit 600 provided in the head 21. sdB1 to sdBn) are generated and output to the drive data transmission unit 140 in parallel format. For example, the original drive data sdA and sdB may be digital data obtained by analog / digital conversion of a drive signal waveform (drive waveform), or the length of each section having a constant slope in the drive waveform and each slope. It may be digital data that defines a correspondence relationship, or digital data that selects one of a plurality of types of drive waveforms stored in a storage unit (not shown).

  The control signal conversion unit 110 includes a plurality of types of original control signals (original clock signals sSck1 to Skkn, original print data signals sSI1 to sSIn, original latch signals sLAT1 to sLATn, and original change signals sCH1 to sCH1 output from the control signal generation unit 100. sCHn) is converted (serialized) into a plurality of serial-format serial control signals sS (sS1 to sSn) and output to the control signal transmission unit 120. In addition, the control signal conversion unit 110 generates a transfer clock signal used for high-speed serial data transfer, and embeds the transfer clock signal together with a plurality of types of original control signals in the serial control signal.

  The control signal transmission unit 120 converts each of the plurality of serial control signals sS (sS1 to sSn) output from the control signal conversion unit 110 into a plurality of original control differential signals dCS (dCS1 to dCSn), and outputs a plurality of ejections. Transmit to each of the units 20 (20-1 to 20-n).

  For example, the control signal transmission unit 120 converts the serial control signal into a differential signal of an LVDS (Low Voltage Differential Signaling) transfer method, and transmits it to each of the ejection units 20 (20-1 to 20-n). Since the differential signal of the LVDS transfer system has an amplitude of about 350 mV, high-speed data transfer can be realized. Note that the control signal transmission unit 120 outputs 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 to the ejection units 20 (20-1 to 20-). You may transmit to each of n). Further, the control signal conversion unit 110 does not embed the transfer clock signal in the serial control signal, and the control signal transmission unit 120 independently transfers the transfer clock signal to each of the ejection units 20 (20-1 to 20-n). You may send it.

  The drive data transmission unit 140 converts the plurality of original drive data sdA (sdA1 to sdAn) and sdB (sdB1 to sdBn) output from the control signal generation unit 100 into original serial drive differential signals dDSA (dDSA1 to dDSAn), respectively. , DDSB (dDSB1 to dDSBn) and transmitted to the drive circuit unit 30.

For example, the plurality of original drive differential signals dDSA (dDSA1 to dDSAn) and dDSB (dDSB1 to dDSBn) output from the drive data transmission unit 140 are digital signals, specifically, the drive data transmission unit 140. May convert a plurality of original drive differential signals dDSA (dDSA1 to dDSAn) and dDSB (dDSB1 to dDSBn) into high-speed differential signals such as LVDS and transmit them to the drive circuit unit 30. The drive data transmission unit 140 serializes each of the plurality of original drive data sdA (sdA1 to sdAn) and sdB (sdB1 to sdBn) into a serial signal in the serial format, and converts the serial signal to the original drive differential signal dDSA ( dDSA1 to dDSAn), dDSB (dDSB1 to dDSBn) may be converted and transmitted to the drive circuit unit 30. The drive data transmission unit 140 may embed a transfer clock signal used for high-speed serial data transfer in the differential signal, or may transmit the transfer clock signal to the drive circuit unit 30 independently.

  The drive circuit unit 30 includes a drive data receiving unit 310, a plurality of drive circuits 50-a (50-a1 to 50-an), and a plurality of 50-b (50-b1 to 50-bn). .

  The drive data receiving unit 310 receives a plurality of original drive differential signals dDSA (dDSA1 to dDSAn) and dDSB (dDSB1 to dDSBn) transmitted from the control unit 10, and a plurality of ejection units 20 (20-1 to 20-). A plurality of drive data dA (dA1 to dAn) and dB (dB1 to dBn), which are data indicating drive signals for driving the ejection unit 600 provided in n), are output. Specifically, the drive data receiving unit 310 differentially amplifies each of the received original drive differential signals dDSA (dDSA1 to dDSAn) and dDSB (dDSB1 to dDSBn), and is embedded in the differentially amplified signal. The transfer clock signal is restored, and based on the transfer clock signal, the plurality of original drive data sdA (sdA1 to sdAn) and sdB (sdB1 to sdBn) included in the differentially amplified signal are restored. As a result, a plurality of drive data dA (dA1 to dAn) and dB (dB1 to dBn) are output in parallel.

  The plurality of drive circuits 50-a (50-a1 to 50-an) are based on the plurality of drive data dA (dA1 to dAn) output from the drive data receiving unit 310, and the ejection units 20 (20-1 to 20). The drive signals COM-A (COM-A1 to COM-An) to be applied to the respective one ends of the piezoelectric elements 60 included in -n) are generated. Similarly, the plurality of drive circuits 50-b (50-b1 to 50-bn) are based on the plurality of drive data dB (dB1 to dBn) output from the drive data receiving unit 310, and the discharge units 20 (20-1 to 20-1 to 20-1). 20-n), drive signals COM-B (COM-B1 to COM-Bn) to be applied to respective one ends of the piezoelectric elements 60 included in 20-n) are generated.

  For example, if the drive data dA and dB are digital data obtained by A / D converting the waveforms of the drive signals COM-A and COM-B, the drive circuits 50-a and 50-b respectively receive the drive data dA and dB. A D / A converted analog signal is generated, and thereafter, D-class amplification is performed to generate drive signals COM-A and COM-B.

  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 waveforms of the drive signals COM-A and COM-B, respectively, the drive circuit 50-a and 50-b generate the analog signals satisfying the correspondence between the lengths and inclinations of the sections defined by the drive data dA and dB, respectively, and then perform class D amplification to drive the signals COM-A and COM-. B may be generated.

  For example, if the drive data dA and dB are digital data for selecting one of a plurality of types of drive waveforms stored in a storage unit (not shown), the drive circuits 50-a and 50-b are read out. After generating the analog signals selected by the drive data dA and dB, respectively, the drive signals COM-A and COM-B may be generated by class D amplification.

  As described above, the drive data dA and dB are data defining the waveforms of the drive signals COM-A and COM-B, respectively. The plurality of drive circuits 50-a (50-a1 to 50-an) and the plurality of drive circuits 50-b (50-b1 to 50-bn) are inputted with drive data dA (dA1 to dAn) and dB. (DB1 to dBn), output drive signals COM-A (COM-A1 to COM-An), COM-B (COM-B1 to COM-Bn), and the discharge unit 20 (20-1) to which the drive signals are input. ˜20-n) are different, and the circuit configuration may be the same.

  In the first embodiment, drive data dA1 and dB1 are input to the drive circuits 50-a1 and 50-b1, and the drive signals COM-A1 (an example of “first drive signal”) and COM-B1 (“second drive signal”) are input. Is output to the discharge unit 20-1. Similarly, drive data 50Ai (i is any one of 1 to n) and 50-bi (i is any one of 1 to n) include drive data dAi (i is any one of 1 to n), dBi. (I is any one of 1 to n) is input, and the drive signal COM-Ai (i is any one of 1 to n) and COM-Bi (i is any one of 1 to n) are supplied to the discharge unit 20-i. (I is any one of 1 to n).

  Each of the drive circuits 50-a (50-a1 to 50-an) and 50-b (50-b1 to 50-bn) has a constant voltage based on a power supply voltage input from a power supply circuit (not shown). A signal VBS (for example, 6V) is generated. The constant voltage signal VBS generated by the drive circuit 50-ai (i is any one of 1 to n) and the constant voltage signal VBS generated by the drive circuit 50-bi (i is any one of 1 to n) are driven. The circuit units 30 are electrically connected to each other. And it is output to the discharge unit 20-i (i is any one of 1 to n) as one constant voltage signal VBS. The constant voltage signal VBS may be a ground potential.

  That is, the drive circuit unit 30 receives a plurality of original drive differential signals dDSA (dDSA1 to dDSAn) and dDSB (dDSB1 to dDSBn) input from the control unit 10, and includes drive signals COM-A1 and COM-B1. A plurality of drive signals COM-A (COM-A1 to COM-An), COM-B (COM-B1 to COM-Bn) and a constant voltage signal VBS (for example, 6 V) are output to the discharge units 20 (20-1 to 20). -N).

  Each of the plurality of ejection units 20 (20-1 to 20-n) includes a control signal receiving unit 240, a control signal restoring unit 250, a selection circuit 210, and the head 21. Each of the plurality of discharge units 20 (20-1 to 20-n) has a plurality of original control differential signals dCS (dCS1 to dCSn) input from the control unit 10 and a drive input from the drive circuit unit 30. A plurality of drive signals COM-A (COM-A1 to COM-An) and COM-B (COM-B1 to COM-Bn) including signals COM-A1 and COM-B1 and a constant voltage signal VBS are input. Then, based on the input signal, the piezoelectric element 60 (an example of “driving element”) included in the head 21 is driven to eject liquid from the ejection unit 600 and perform printing on the print medium P. Each of the plurality of discharge units 20 (20-1 to 20-n) has the same configuration except that the input signals are different. Therefore, when it is not necessary to distinguish in particular, the discharge unit 20-1 will be described.

  The control signal receiving unit 240 receives the original control differential signal dCS1 output from the control unit 10 (control signal transmitting unit 120). The control signal receiving unit 240 converts the input original control differential signal dCS1 into a serial control signal and outputs the serial control signal to the control signal restoring unit 250. Specifically, the control signal receiving unit 240 may receive an LVDS transfer type differential signal, differentially amplify the differential signal, and convert the differential signal into a serial control signal.

Based on the serial control signal converted by the control signal receiving unit 240, the control signal restoration unit 250 controls a plurality of types of control signals (clock signal Sck1, print data) for controlling the liquid ejection from the ejection unit 600 provided in the head 21. Signal SI1, latch signal LAT1, and change signal CH1) are generated. Specifically, the control signal restoration unit 250 restores the transfer clock signal embedded in the serial control signal output from the control signal reception unit 240, and converts the transfer clock signal into the serial control signal based on the transfer clock signal. By restoring (deserializing) a plurality of types of original control signals (original clock signal sSck1, original print data signal sSI1, original latch signal sLAT1, and original change signal sCH1), a plurality of types of control signals in parallel format are obtained. (Clock signal Sck1, print data signal SI1, latch signal LAT1
And the change signal CH1) are generated and output to the selection circuit 210.

  The selection circuit 210 outputs a drive signal Vout to each of the plurality of ejection units 600 provided in the head 21. Specifically, the selection circuit 210 selects one of the drive signals COM-A1 and COM-B1 based on the clock signal Sck1, the print data signal SI1, the latch signal LAT1, and the change signal CH1, respectively, and drives the drive signal Vout. Are output to the head 21, or none is selected and the output is set to high impedance. The details of the circuit configuration of the selection circuit 210 will be described later (see FIG. 8).

  The head 21 has a plurality of ejection units 600 including the piezoelectric elements 60. The drive signal Vout output from the selection circuit 210 is applied to one end of each of the piezoelectric elements 60 included in the plurality of ejection units 600. A constant voltage signal VBS input from the drive circuit unit 30 is commonly applied to the other ends of the piezoelectric elements 60 included in the plurality of ejection units 600. Then, the piezoelectric element 60 is displaced according to the potential difference between the drive signal Vout applied to one end and the constant voltage signal VBS applied to the other end, and ejects ink. The details of the configuration of the head 21 and the piezoelectric element 60 will be described later (see FIG. 3).

1.3 Configuration of Print Head 1.3.1 Configuration of Ejection Unit Here, a configuration for ejecting ink by driving the piezoelectric element 60 will be briefly described.

  FIG. 3 is a diagram illustrating a schematic configuration corresponding to one ejection unit 600 in the head 21. As shown in FIG. 3, the head 21 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 ink storage unit 8 to the supply port 661 through an ink tube or the like.

  The discharge unit 600 includes a piezoelectric element 60, a vibration plate 621, a cavity (pressure chamber) 631, and a nozzle 651. Among these, 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. 3 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 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. 3 is bent vertically 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 signal Vout increases, and to bend downward when the voltage of the drive signal 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.

  Further, the piezoelectric element 60 is provided in the head 21 corresponding to the cavity 631 and the nozzle 651, and is also provided corresponding to the selection unit 230 (see FIGS. 8 and 10) described later. For this reason, the set of the piezoelectric element 60, the cavity 631, the nozzle 651, and the selection unit 230 is provided for each nozzle 651.

1.3.2 Configuration of Drive Signal FIG. 4 is a diagram illustrating an example of the arrangement of the nozzles 651. As shown in FIG. 4, the nozzles 651 are arranged in, for example, two rows. Specifically, when viewed in one row, the plurality of nozzles 651 are arranged at a pitch Pv along the sub-scanning direction Y, while the two rows are separated from each other by the pitch Ph in the main scanning direction X, and The relationship is shifted by half the pitch Pv in the sub-scanning direction Y.

  The nozzle 651 is provided with a pattern corresponding to each color of ink used (for example, C (cyan), M (magenta), Y (yellow), B (black), etc.) along the main scanning direction X, for example. In the following description, for the sake of simplification, a case of expressing a monochrome gradation will be described.

  FIG. 5 is a diagram for explaining the basic resolution of image formation by the nozzle arrangement shown in FIG. This drawing is an example of a method (first method) in which an ink droplet is ejected once from the nozzle 651 to form a single dot for the sake of simplicity, and a black circle is an ink. A dot formed by landing of a droplet is shown.

  When the carriage 24 supporting the discharge unit 20 moves at a speed v in the main scanning direction X, as shown in FIG. 5, the dot interval D (in the main scanning direction X) of dots formed by the landing of ink droplets. And the speed v have the following relationship.

  That is, when one dot is formed by one ink droplet ejection, the dot interval D is a value obtained by dividing the velocity v by the ink ejection frequency f (= v / f), in other words, the ink droplets This is indicated by the distance that the discharge unit 20 moves in the cycle (1 / f) of repeated discharge.

  In the example of FIGS. 4 and 5, the ink droplets ejected from the two rows of nozzles 651 are aligned in the same row in the print medium P with the relationship that the pitch Ph is proportional to the dot interval D by the coefficient n. It ’s landed like this. For this reason, as shown in FIG. 5, the dot interval in the sub-scanning direction Y is half of the dot interval in the main scanning direction X. Needless to say, the arrangement of dots is not limited to the example shown in the figure.

  In order to realize high-speed printing, simply, the speed v at which the carriage 24 supporting the discharge unit 20 moves in the main scanning direction X may be increased. However, simply increasing the speed v increases the dot interval D. For this reason, in order to achieve high-speed printing while ensuring a certain level of resolution, it is necessary to increase the number of dots formed per unit time by increasing the ink ejection frequency f. In addition to the printing speed, in order to increase the resolution, the number of dots formed per unit area may be increased. However, when the number of dots is increased, if the amount of ink is not reduced, not only the adjacent dots are combined but also the printing speed is reduced unless the ink ejection frequency f is increased. Thus, in order to realize high-speed printing and high-resolution printing, it is preferable to increase the ink ejection frequency f.

On the other hand, as a method of forming dots on the print medium P, in addition to a method of ejecting ink droplets once to form one dot, ink droplets can be ejected twice or more in a unit period, A method of forming one dot (second method) by combining one or more ejected ink droplets and combining the landed one or more ink droplets, or combining these two or more ink droplets There is a method (third method) for forming two or more dots. In the first embodiment, by using the second method, for each dot, the ink is ejected at most twice, so that “large dot”, “medium dot”, “small dot”, and “non-recording (no dot)” 4 gradations are expressed.

  In order to express these four gradations, in the first embodiment, a drive signal COM-Ai (i is any one of 1 to n) and COM-Bi (i is any one of 1 to n) are prepared. Each has a first half pattern and a second half pattern in one period of dot formation. The drive signals COM-Ai and CMO-Bi are selected (or not selected) in accordance with the gradation to be expressed in the first half and the second half of one cycle and supplied to the piezoelectric element 60.

  FIG. 6 is a diagram illustrating an example of waveforms of the drive signals COM-Ai and COM-Bi. As shown in FIG. 6, the drive signal COM-Ai is a period from when the latch signal LATi (i is any one of 1 to n) to when the change signal CHi (i is any one of 1 to n) is risen. The trapezoidal waveform Adp1 arranged at T1 and the trapezoidal waveform Adp2 arranged during the period T2 from the rise of the change signal CHi to the next rise of the latch signal LATi are continuous waveforms. A period composed of the period T1 and the period T2 is defined as a period Ta, and a new dot is formed on the print medium P every period Ta.

  In the first embodiment, the trapezoidal waveforms Adp1 and Adp2 are substantially the same waveforms. If each is supplied to one end of the piezoelectric element 60, the waveform is such that a predetermined amount, specifically, a medium amount of ink is ejected from the nozzle 651 corresponding to the piezoelectric element 60.

  The drive signal COM-Bi has a waveform in which the trapezoidal waveform Bdp1 arranged in the period T1 and the trapezoidal waveform Bdp2 arranged in the period T2 are continuous. Among these, the trapezoidal waveform Bdp1 is a wave for finely vibrating the ink in the vicinity of the opening portion of the nozzle 651 to prevent the ink viscosity from increasing. For this reason, even if the trapezoidal waveform Bdp1 is supplied to one end of the piezoelectric element 60, ink droplets are not ejected from the nozzle 651 corresponding to the piezoelectric element 60. The trapezoidal waveform Bdp2 is 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 an amount of ink smaller than the predetermined amount to be ejected from the nozzle 651 corresponding to the piezoelectric element 60.

  Thus, in the first embodiment, the drive signal COM-Ai and the drive signal COM-Bi applied to one end of the piezoelectric element 60 are configured with different waveforms. In this way, by configuring the drive signal COM-Ai and the drive signal COM-Bi with different waveforms, it becomes possible to select a plurality of amounts of ink ejected from the ejection unit 600, and various types of print media P can be selected. It becomes possible to form dots of a large size.

  The voltage at the start timing and the voltage at the end timing of the trapezoidal waveforms Adp1, Adp2, Bdp1, and Bdp2 are all the same as the voltage Vc. That is, the trapezoidal waveforms Adp1, Adp2, Bdp1, and Bdp2 are waveforms that start at the voltage Vc and end at the voltage Vc, respectively.

  FIG. 7 is a diagram illustrating waveforms of the drive signals Vout corresponding to “large dots”, “medium dots”, “small dots”, and “non-recording” in the first embodiment.

As shown in FIG. 7, the drive signal Vout corresponding to the “large dot” causes the trapezoidal waveform Adp1 of the drive signal COM-Ai in the period T1 and the trapezoidal waveform Adp2 of the drive signal COM-Ai in the period T2 to be continuous. It has become a waveform. When this drive signal Vout is supplied to one end of the piezoelectric element 60, a medium amount of ink is ejected twice from the nozzle 651 corresponding to the piezoelectric element 60 in the period Ta. For this reason, in the period Ta, the respective inks land and coalesce on the printing medium P to form large dots.

  The drive signal Vout corresponding to “medium dot” has a waveform in which the trapezoidal waveform Adp1 of the drive signal COM-Ai in the period T1 and the trapezoidal waveform Bdp2 of the drive signal COM-Bi in the period T2 are continuous. When this drive signal Vout is supplied to one end of the piezoelectric element 60, a medium amount of ink and a small amount of ink are divided into two from the nozzle 651 corresponding to the piezoelectric element 60 in the period Ta. Discharged. For this reason, medium dots are formed on the print medium P in the cycle Ta.

  The drive signal Vout corresponding to the “small dot” has a voltage Vc immediately before held by the capacitive property of the piezoelectric element 60 in the period T1 and a trapezoidal waveform Bdp2 of the drive signal COM-Bi in the period T2. It has a waveform. When the drive signal 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 print medium P in the cycle Ta.

  In the drive signal Vout corresponding to “non-recording”, the trapezoidal waveform Bdp1 of the drive signal COM-Bi in the period T1 and the voltage Vc immediately before held by the capacitance of the piezoelectric element 60 in the period T2 are continued. It has a waveform.

  When this drive signal 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 T1, and no ink is ejected in the period Ta. For this reason, ink does not land on the print medium P, and no dots are formed.

1.4 Configuration of Selection Circuit FIG. 8 is a diagram illustrating a configuration of the selection circuit 210. As shown in FIG. 8, the selection circuit 210 includes a selection control unit 220 and a plurality of selection units 230.

  The selection control unit 220 is supplied with a clock signal Ski, a print data signal SIi, a latch signal LATi, and a change signal CHi. In the selection control unit 220, a set of a shift register (S / R) 222, a latch circuit 224, and a decoder 226 is provided corresponding to each selection unit 230. As described above, the selection unit 230 is provided corresponding to each of the piezoelectric elements 60 (nozzles 651). That is, the number of sets of the shift register (S / R) 222, latch circuit 224, and decoder 226 included in the selection circuit 210 is the same as the total number m of the nozzles 651 included in the two nozzle rows 650.

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

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

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

  In order to distinguish the shift register 222, the first stage, the second stage,..., And the m stage are shown in order from the upstream side to which the print data signal SIi is supplied.

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

  Each of the m decoders 226 decodes 2-bit print data (SIH, SIL) latched by each of the m latch circuits 224, and a period T1 defined by the latch signal LATi and the change signal CHi. , The selection signals Sa and Sb are output every T2, and the selection by the selection unit 230 is defined.

  FIG. 9 is a diagram showing the decoded contents in the decoder 226. For example, if 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 the H and L levels in the period T1, respectively, and the period T2 Means output as the L and H levels, respectively.

  Note that the logic levels of the selection signals Sa and Sb are level-shifted to higher amplitude logic by a level shifter (not shown) than the logic levels of the clock signal Skki, the print data signal SIi, the latch signal LATi, and the change signal CHi. The

  The selection unit 230 is provided corresponding to each of the piezoelectric elements 60 (nozzles 651). That is, the number of selection units 230 included in one selection circuit 210 is the same as the total number m of nozzles 651 included in the two nozzle rows 650.

  FIG. 10 is a diagram illustrating a configuration of the selection unit 230 corresponding to one piezoelectric element 60 (nozzle 651).

  As shown in FIG. 10, the selection unit 230 includes inverters (NOT circuits) 232a and 232b and transfer gates 234a and 234b.

  The selection signal Sa from the decoder 226 is supplied to a positive control terminal that is not circled in the transfer gate 234a, while being logically inverted by the inverter 232a and negatively controlled 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 COM-Ai is supplied to the input terminal of the transfer gate 234a, and the drive signal COM-Bi 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 signal Vout is output to the ejection unit 600 via the common connection terminal.

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

  As described above, the selection unit 230 exclusively applies the drive signals COM-Ai and COM-Bi to the piezoelectric elements 60 included in the ejection unit 600 as the drive signal Vout based on the selection signals Sa and Sb.

  Next, the operation of the selection circuit 210 will be described with reference to FIG.

  The print data signal SIi is serially supplied in synchronization with the clock signal Skki and is sequentially transferred in the shift register 222 corresponding to the nozzle. When the supply of the clock signal Scchi is stopped, the shift register 222 is in a state where the 2-bit print data (SIH, SIL) corresponding to the nozzle 651 is held. The print data signal SIi is supplied in the order corresponding to the last m stages,..., Two stages, and one stage nozzles in the shift register 222.

  Here, when the latch signal LATi rises, each of the latch circuits 224 latches the 2-bit print data (SIH, SIL) held in the shift register 222 at the same time. In FIG. 11, LT1, LT2,..., LTm indicate 2-bit print data (SIH, SIL) latched by the latch circuit 224 corresponding to the 1-stage, 2-stage,. Yes.

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

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

  When the print data (SIH, SIL) is (1, 1), the selection unit 230 selects the drive signal COM-Ai (trapezoidal waveform Adp1) because the selection signals Sa and Sb are at the H and L levels in the period T1. Since the Sa and Sb are at the H and L levels even during the period T2, the drive signal COM-Ai (the trapezoidal waveform Adp2) is selected. As a result, the drive signal Vout corresponding to the “large dot” shown in FIG. 7 is generated.

  In addition, when the print data (SIH, SIL) is (1, 0), the selection unit 230 outputs the drive signal COM-Ai (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 H levels, the drive signal COM-Bi (trapezoidal waveform Bdp2) is selected. As a result, the drive signal Vout corresponding to the “medium dot” shown in FIG. 7 is generated.

In addition, when the print data (SIH, SIL) is (0, 1), the selection unit 230 selects any of the drive signals COM-Ai and COM-Bi because the selection signals Sa and Sb are at the L and L levels in the period T1. In the period T2, Sa and Sb are at L and H levels, so the drive signal COM
-Bi (trapezoidal waveform Bdp2) is selected. As a result, the drive signal Vout corresponding to the “small dot” shown in FIG. 7 is generated. Note that since neither the drive signal COM-Ai nor COM-Bi is selected in the period T1, one end of the piezoelectric element 60 is opened. However, the drive signal Vout has the voltage Vc immediately before due to the capacitance of the piezoelectric element 60. Retained.

  In addition, when the print data (SIH, SIL) is (0, 0), the selection unit 230 outputs the drive signal COM-Bi (trapezoidal waveform Bdp1) because the selection signals Sa and Sb are at the L and H 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 COM-Ai and COM-Bi is selected. As a result, the drive signal Vout corresponding to “non-recording” shown in FIG. 7 is generated. Note that, during the period T2, since neither the drive signal COM-Ai nor COM-Bi is selected, one end of the piezoelectric element 60 is opened. However, due to the capacitance of the piezoelectric element 60, the drive signal Vout has the immediately preceding voltage Vc. Retained.

  Note that the drive signals COM-Ai and COM-Bi shown in FIGS. 6 and 11 are merely examples. Actually, various combinations of waveforms prepared in advance are used according to the moving speed of the carriage 24 and the properties of the print medium P.

  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 COM-Ai and COM-Bi illustrated in FIGS. 6 and 11 have waveforms that are inverted with respect to the voltage Vc. Become.

1.5 Internal Configuration of Liquid Ejecting Device FIG. 12 is a diagram schematically showing an internal configuration when the liquid ejecting device 1 is viewed from the sub-scanning direction Y. As shown in FIG. 12, the liquid ejection apparatus 1 includes a carriage 24, a carriage guide shaft 32, a platen 33, a capping mechanism 35, and a maintenance mechanism 80.

  The carriage 24 moves (reciprocates) within the range of the movable region R along the carriage guide shaft 32 based on the control of the carriage moving mechanism 41 (see FIG. 2). A plurality of discharge units 20 (20-1 to 20-n) including the head 21 are mounted on the carriage 24. Then, the ink ejection surface of the head 21 is provided so as to face the print medium P, whereby printing is performed by ejecting ink onto the print medium P.

  The platen 33 is provided with a roller (not shown) that conveys the print medium P, conveys the print medium P in the sub-scanning direction Y, and holds the print medium P when ink is ejected to the print medium P. To do. That is, the maximum width in which the liquid ejecting apparatus 1 can perform serial printing is a range in which the printing medium P is held by the platen 33, and is equal to the platen width PW that is the width of the platen 33 in the main scanning direction X. The platen width PW is set wider than the standard dimension Ws of the medium width W which is the width of the print medium P in the main scanning direction X in order to stably hold and transport the print medium P. In the first embodiment, the platen width PW (that is, the maximum printing width) satisfies Ws <PW ≦ Ws × 1.15 with respect to the standard dimension Ws. In other words, the liquid ejection apparatus 1 corresponding to the standard dimension Ws is a printer (liquid ejection apparatus 1) having a maximum printing width larger than the standard dimension Ws and 115% or less of the standard dimension Ws.

For example, a printer (liquid ejecting apparatus 1) in which the standard dimension Ws of the medium width W is 24 inches is a printer (referred to as a “24-inch compatible printer”) having a maximum printing width corresponding to 24 inches. The maximum printing width is greater than 24 inches and 27.6 inches or less. Further, a printer (liquid ejecting apparatus 1) having a standard dimension Ws of the medium width W of 36 inches is a printer (referred to as a “36-inch compatible printer”) having a maximum printing width of 36 inches. Specifically, The maximum printing width is larger than 36 inches and 41.4 inches or less. A printer (liquid ejecting apparatus 1) having a standard width Ws of 44 inches for the medium width W is a printer corresponding to a maximum print width of 44 inches (referred to as a “44-inch compatible printer”). The maximum printing width is greater than 44 inches and not more than 50.6 inches. A printer (liquid ejecting apparatus 1) having a standard dimension Ws of the medium width W of 64 inches is a printer (referred to as a “64-inch compatible printer”) having a maximum printing width of 64 inches. Specifically, The maximum printing width is greater than 64 inches and 73.6 inches or less.

  A capping mechanism 35 that seals the nozzle formation surface (ink discharge surface) of the head 21 is provided at the home position where the carriage 24 moves (reciprocates). The home position is also a position where the plurality of ejection units 20 (20-1 to 20-n) supported by the carriage 24 are on standby when the liquid ejection apparatus 1 is not executing printing. Thus, the capping mechanism width CW, which is the width of the home position (capping mechanism 35) in the main scanning direction X, is the main scanning direction X of the carriage 24 that supports the plurality of ejection units 20 (20-1 to 20-n). It is preferable that the discharge width DW is equal to or greater than the width.

  In the movable region R of the carriage 24, a maintenance mechanism 80 is provided in a place farthest from the home position. As a maintenance process, the maintenance mechanism 80 removes foreign matter such as cleaning powder (pumping process) for sucking thickened ink or bubbles in the discharge unit 600 by a tube pump (not shown) and paper dust adhering to the vicinity of the nozzle. A wiping process of wiping with a wiper is performed. During the execution of the maintenance process, the carriage 24 that supports the plurality of ejection units 20 (20-1 to 20-n) and the platen that is the printing area when viewed from the vertical direction Z in order to prevent the printing area from being stained. It is preferable that 33 does not overlap. Furthermore, the maintenance mechanism width MW, which is the width of the maintenance mechanism 80 in the main scanning direction X, is preferably provided to be equal to or greater than the ejection width DW, which is the width of the carriage 24 in the main scanning direction X.

  Further, the liquid ejection apparatus 1 includes a control unit 10, a drive circuit unit 30, and a plurality of cables 190. In the first embodiment, between the control unit 10 and a plurality of discharge units 20 (20-1 to 20-n) mounted on the carriage 24, between the control unit 10 and the drive circuit unit 30, and the drive circuit unit 30. And a plurality of discharge units 20 (20-1 to 20-n) mounted on the carriage 24 are connected by one or a plurality of cables 190, respectively.

  Specifically, the control unit 10 and the plurality of discharge units 20 (20-1 to 20-n) mounted on the carriage 24 are electrically connected by a cable 191 that is one of the cables 190. The cable 191 transfers a plurality of original control differential signals dCS (dCS1 to dCSn) from the control unit 10 to the discharge unit 20. The control unit 10 and the drive circuit unit 30 are electrically connected by a cable 192 that is one of the cables 190. The cable 192 transfers the original drive differential signals dDSA (dDSA1 to dDSAn) and dDSB (dDSB1 to dDSBn) from the control unit 10 to the drive circuit unit 30. The drive circuit unit 30 and the plurality of discharge units 20 (20-1 to 20-n) are electrically connected by a cable 193 that is one of the cables 190. The cable 193 (an example of “cable”) transmits drive signals COM-A (COM-A1 to COM-An), COM-B (COM-B1 to COM-Bn) and a constant voltage signal VBS from the drive circuit unit 30. Transfer to the discharge unit 20.

  Here, the cable 191 for electrically connecting the control unit 10 and the discharge unit 20 mounted on the carriage 24 and the cable 192 for electrically connecting the control unit 10 and the drive circuit unit 30 are low-amplitude differentials. Transfer signal (voltage signal). In contrast, the cable 193 that electrically connects the drive circuit unit 30 and the discharge unit 20 transfers a large current signal having a large voltage amplitude. For this reason, in order to reduce the mutual interference of various signals transferred by the cable 190, it is effective to reduce the mutual interference of the signals transferred by the cable 193.

1.6 Configuration of Drive Signal Transmission Wiring Here, the configuration of the cable 193 transferred from the drive circuit unit 30 to the discharge unit 20 will be described with reference to FIGS. 13 and 14. In order to simplify the description, the cable 193 sends the drive signals COM-A1 and COM-B1 generated by the drive circuits 50-a1 and 50-b1 included in the drive circuit unit 30 to the discharge unit 20-1. The description will be made as a cable (wiring) to be transferred.

  FIG. 13 is a schematic diagram showing the configuration of the cable 193. In the first embodiment, the cable 193 is a flat flexible flat cable (FFC: Flexible Flat Cable) in which a plurality of conductors are arranged. Specifically, the conductor 181, 182, 183, 184, 189 is arranged in parallel in the cable 193 from the first end 195 side to the second end 196 side. The drive circuit unit 30 transfers a plurality of signals including the drive signals COM-A1, COM-B1 and the constant voltage signal VBS to the discharge unit 20-1 via the conductors 181, 182, 183, 184, and 189, respectively. To do.

  FIG. 14 is a diagram illustrating an example of a configuration of a signal transferred through the cable 193. As shown in FIG. 14, a voltage signal VH for supplying power is applied to the conductor 181, and a voltage signal GND indicating a ground potential is applied to the conductor 189. Thus, the power for operating the discharge unit 20-1 is supplied by the potential difference between the conductor 181 and the conductor 189.

  Some of the plurality of conductors included in the cable 193 are a plurality of conductors to which the drive signals COM-A1 and COM-B1 applied to one end of the piezoelectric element 60 are applied (the conductors 182 and 182 in this embodiment). 184, hereinafter referred to as “first conductor group”), some of which are different from one or more conductors (this embodiment) to which a constant voltage signal VBS applied to the other end of the piezoelectric element 60 is applied. And is hereinafter referred to as a “second conductor group”). Specifically, the drive signal COM-A1 is applied to the conductor 182 (an example of “first conductor”). A constant voltage signal VBS is applied to the conductor 183 (an example of a “third conductor”). In addition, the drive signal COM-B1 is applied to the conductor 184 (an example of “second conductor”).

  At this time, the conductor 182 to which the drive signal COM-A1 applied to one end of the piezoelectric element 60 is applied and the conductor 183 to which the constant voltage signal VBS applied to the other end of the piezoelectric element 60 are applied are adjacent to each other. A conductor 184 that is a conductor that is applied with a drive signal COM-B1 that is applied exclusively to the drive signal COM-A1 to one end of the piezoelectric element 60; and a constant voltage signal that is applied to the other end of the piezoelectric element 60. The conductor 183 to which VBS is applied is a conductor located adjacent to the conductor 183.

  Note that the cable 193 may include a plurality of conductors other than those described above, and signals other than those described above may be applied thereto. Further, the voltage signal VH and the voltage signal GND may be transferred by different cables.

As described above, the drive signal COM-A1 and the drive signal COM-B1 applied to one end of the piezoelectric element 60 are exclusively applied to the piezoelectric element 60. Here, a path of current generated when the drive signal COM-A1 is applied to one end of the piezoelectric element 60 and a path of current generated when the drive signal COM-B1 is applied to one end of the piezoelectric element 60 are described. This will be described with reference to FIGS. 15 and 16.

  FIG. 15 is a diagram showing a current flow when the drive signal COM-A1 is applied to the piezoelectric element 60. As shown in FIG. The dashed-dotted line shown in FIG. 15 indicates the path of current flowing from the drive signal COM-A1 to the piezoelectric element 60, and the broken line indicates the path of current flowing from the piezoelectric element 60 to the drive circuits 50-a1 and 50-b1. In FIG. 15, four piezoelectric elements 60 included in the discharge unit 20-1 are assumed to simplify the description. In addition, the selection units 230 provided corresponding to the four piezoelectric elements 60 are all described as selecting the drive signal COM-A1.

  The drive signal COM-A1 output from the drive circuit 50-a1 is applied to one end of the piezoelectric element 60 via the conductor 182 and the selection unit 230 of the cable 193. At this time, a current flows through the conductor 182 in the direction from the drive circuit unit 30 to the discharge unit 20-1. The current flowing into the piezoelectric element 60 flows into each of the drive circuits 50-a1 and 50-b1 provided in the drive circuit unit 30 through the conductor 183 to which the constant voltage signal VBS is applied. At this time, a current flows through the conductor 183 in the direction from the discharge unit 20-1 to the drive circuit unit 30. In the first embodiment, the conductor 182 and the conductor 183 are adjacent to each other as shown in FIG. In other words, currents in opposite directions flow through the conductor 182 and the conductor 183 located adjacent to each other. Thereby, the magnetic field generated by the current flowing through the conductor 182 and the magnetic field generated by the current flowing through the conductor 183 cancel each other. Therefore, mutual interference between the conductor 182 and the conductor 183 is reduced.

  Further, at this time, the drive signal COM-B1 output from the drive circuit 50-b1 has its current path to the piezoelectric element 60 blocked by the selection unit 230. Therefore, no current flows through the conductor 184. At this time, the conductor 184 may receive mutual interference due to the magnetic field generated by the current flowing in the adjacent conductor 183. However, in the cable 193 in the first embodiment, the magnetic field generated by the current flowing in the conductor 183 is a conductor. The magnetic field generated by the current flowing through 182 is canceled out. As a result, the drive signal COM-B1 applied to the conductor 184 through which no current flows is less affected by the magnetic field generated by the current flowing through the conductor 183.

  FIG. 16 is a diagram showing a current flow when the drive signal COM-B1 is applied to the piezoelectric element 60. As shown in FIG. A two-dot chain line shown in FIG. 16 indicates a path of current flowing from the drive signal COM-B1 to the piezoelectric element 60, and a broken line indicates a path of current flowing from the piezoelectric element 60 to the drive circuits 50-a1 and 50-b1. In FIG. 16, four piezoelectric elements 60 are included in the discharge unit 20-1 for simplification of description. Further, the description will be made assuming that the selection units 230 provided corresponding to the four piezoelectric elements 60 all select the drive signal COM-B1.

The drive signal COM-B1 output from the drive circuit 50-b1 is applied to one end of the piezoelectric element 60 via the conductor 184 and the selection unit 230 of the cable 193. At this time, a current flows through the conductor 184 in the direction from the drive circuit unit 30 to the discharge unit 20-1. The current flowing into the piezoelectric element 60 flows into each of the drive circuits 50-a1 and 50-b1 provided in the drive circuit unit 30 through the conductor 183 to which the constant voltage signal VBS is applied. At this time, a current flows through the conductor 183 in the direction from the discharge unit 20-1 to the drive circuit unit 30. In the first embodiment, the conductor 184 and the conductor 183 are adjacent to each other as shown in FIG. That is, mutually opposite currents flow through the conductor 184 and the conductor 183 located adjacent to each other. Thereby, the magnetic field generated by the current flowing through the conductor 184 and the magnetic field generated by the current flowing through the conductor 183 cancel each other. Therefore, mutual interference between the conductor 184 and the conductor 183 is reduced.

  Further, at this time, the drive signal COM-A1 output from the drive circuit 50-a1 has the current path to the piezoelectric element 60 blocked by the selection unit 230. Therefore, no current flows through the conductor 182. At this time, the conductor 182 may receive mutual interference due to the magnetic field generated by the current flowing through the adjacent conductor 183. However, in the cable 193 in the first embodiment, the magnetic field generated by the current flowing through the conductor 183 is It is canceled out by the magnetic field generated by the current flowing through the conductor 184. As a result, the influence of the drive signal COM-A1 applied to the conductor 182 where no current flows is affected by the magnetic field generated by the current flowing through the conductor 183 is reduced.

  In FIGS. 15 and 16, the description has been given assuming that all of the selection units 230 provided in the discharge unit 20-1 select the drive signal COM-A <b> 1 (or drive signal COM-B <b> 1). A part of the selection unit 230 provided in the discharge unit 20-1 may select the drive signal COM-A1, and a different part of the selection unit 230 may select the drive signal COM-B1. At this time, the conductor 183 has a current that flows when the drive signal COM-A1 is applied to one end of the piezoelectric element 60 and a current that flows when the drive signal COM-B1 is applied to one end of the piezoelectric element 60. , The summed current flows. Of the current flowing through the conductor 183, the magnetic field generated by the current flowing when the drive signal COM-A1 is applied to one end of the piezoelectric element 60 cancels with the magnetic field generated by the current flowing through the conductor 182. In addition, the magnetic field generated by the current that flows when the drive signal COM-B1 is applied to one end of the piezoelectric element 60 among the current that flows through the conductor 183 cancels with the magnetic field generated by the current that flows through the conductor 184. That is, even when a part of the selection unit 230 provided in the discharge unit 20 selects the drive signal COM-A1 and a different part of the selection unit 230 selects the drive signal COM-B1, the conductors in the cable 193 are connected. Mutual interference is reduced.

  Furthermore, as shown in the first embodiment, any of the plurality of conductors included in the first conductor group (the conductor to which the drive signal COM-A1 or the drive signal COM-B1 is applied) is the second conductor group (constant constant). It is preferable to be positioned on the first end 195 side of the cable 193 with respect to all of one or a plurality of conductors included in the conductor to which the voltage signal VBS is applied. In other words, in the plurality of conductors provided in the cable 193, at least one of the drive signal COM-A1 and the drive signal COM-B1 is the first for all the conductors to which the constant voltage signal VBS is applied. It is applied to the conductor located on the end 195 side. Further, at least one of the drive signal COM-A1 and the drive signal COM-B1 is applied to the conductor located on the second end 196 side with respect to all the conductors to which the constant voltage signal VBS is applied. . As described above, since the conductor to which at least one of the drive signal COM-A1 and the drive signal COM-B1 is applied is positioned, the first conductor is included on both sides of the first conductor or the plurality of conductors included in the second conductor group. Any of a plurality of conductors included in the conductor group can be provided.

  The total number of one or more conductors included in the second conductor group is more preferably smaller by 1 than the total number of the plurality of conductors included in the first conductor group. This makes it possible to alternately arrange one or a plurality of conductors included in the second conductor group and a plurality of conductors included in the first conductor group.

The plurality of conductors included in the first conductor group transfer the drive signal COM-A1 or the drive signal COM-B1 applied to one end of the piezoelectric element 60 from the drive circuit unit 30 to the discharge unit 20-1. Therefore, a current flows through the plurality of conductors included in the first conductor group from the drive circuit unit 30 toward the discharge unit 20-1. In addition, the constant voltage signal VBS applied to the other end of the piezoelectric element 60 is applied to one or more conductors included in the second conductor group. At this time, the current flowing into the piezoelectric element 60 by applying the drive signal COM-A1 or the drive signal COM-B1 to one end of the piezoelectric element 60 is applied to one or more conductors included in the second conductor group. A current returning to the drive circuit unit 30 flows. That is, a current flows in the direction from the discharge unit 20-1 to the drive circuit unit 30 through one or more conductors included in the second conductor group.

  As described above, one or more conductors included in the second conductor group (conductor 183 in this embodiment) and a plurality of conductors included in the first conductor group (conductors 182 and 184 in this embodiment) By alternately arranging, in the cable 193, the magnetic field generated by the current flowing through the plurality of conductors applied with the drive signals COM-A1 and COM-B1 and the constant voltage signal VBS can be efficiently canceled out in a wide range of the cable 193. Is possible.

  Further, according to the first embodiment, the magnetic field generated by the current flowing through the first conductor group when each of the drive signal COM-A1 and the drive signal COM-B1 is applied to the piezoelectric element 60, and the current Magnetic fields generated by the current returning to the drive circuits 50-a1 and b1 through the second conductor group cancel each other. Therefore, even if the signal waveform of the drive signal COM-A1 is different from the signal waveform of the drive signal COM-B1, it is possible to cancel the magnetic field generated by the current flowing in the cable 193 based on each signal. It becomes possible to reduce mutual interference of a plurality of conductors included in the cable 193.

  In the first embodiment, the cable 193 transfers the drive signals COM-A1 and COM-B1 generated in the drive circuits 50-a1 and 50-b1 included in the drive circuit unit 30 to the discharge unit 20-1. The description has been made with the cable (wiring) as a representative, but a plurality of types of drive signals COM-A (COM-A1 to COM-An), COM-B (COM-B1 to COM-Bn), and the drive signals Even in a cable to which a constant voltage signal VBS applied to the other end of the applied piezoelectric element 60 is transferred, a drive signal COM-Ai (i is any one of 1 to n) applied to one end of the piezoelectric element 60. ) And a conductor to which COM-Bi (i is any one of 1 to n) are adjacent to each other, and a constant voltage signal VBS applied to the other end of the piezoelectric element 60 is applied. Ru Body it is sufficient if the position.

  Furthermore, in the first embodiment, the magnetic field generated in the cable 193 connecting the drive circuit unit 30 and the discharge unit 20 is canceled, so that the inductance component generated in the cable 193 can also be reduced.

  For example, in a liquid ejection apparatus 1 (Large Format Printer (LFP)) capable of performing serial printing on a medium having an A3 short side width or more, the moving distance of the carriage 24 becomes long, and the drive circuit Since the cable 193 connecting the unit 30 and the discharge unit 20 (20-1 to 20-n) can be 1 m or longer, the inductance component of the cable (cable 193) increases. When the inductance component of the cable 193 connecting the drive circuit unit 30 and the discharge unit 20 is increased, waveform distortion such as overshoot or undershoot occurs in the drive signals COM-A and COM-B, and the liquid discharge device 1 There is a possibility of deteriorating the discharge characteristics.

  Therefore, in the cable 193 connecting the drive circuit unit 30 and the discharge unit 20 as shown in the first embodiment, the inductance component generated in the cable 193 is reduced by canceling out the magnetic field generated between the conductors, thereby reducing the A3 short side. In the liquid ejection apparatus 1 capable of performing serial printing on a medium having a width or more, various problems due to the inductance component of the cable 193 including the above-described waveform distortion can be reduced. Therefore, a particularly significant effect can be obtained in the liquid ejecting apparatus 1 capable of performing serial printing on a medium having an A3 short side width or more.

1.7 Actions / Effects As described above, according to the liquid ejection apparatus 1 according to the present embodiment, the drive signal COM-A, the drive signal COM-B, and the constant voltage signal VBS are transferred to the ejection unit 20. In the cable 193, the drive signal COM-A applied to one end of the piezoelectric element 60 and the conductor (conductors 182 and 184) to which the drive signal COM-B is applied are applied to the other end of the piezoelectric element 60. By positioning the conductor (conductor 183) to which the constant voltage signal VBS is applied, the conductor (conductors 182 and 184) to which the drive signal COM-A and the drive signal COM-B are applied and the constant voltage signal VBS are Magnetic fields generated by current flowing through each of the applied conductors (conductor 183) cancel each other. Therefore, mutual interference of signals transferred through the cable 193 can be reduced. Therefore, according to the liquid discharge apparatus according to this application example, it is possible to discharge liquid with high accuracy.

  Further, according to the liquid ejection apparatus 1 according to the present embodiment, a plurality of conductors (first conductor group) to which the drive signal COM-A or the drive signal COM-B is applied among the plurality of conductors provided in the cable 193. And one or a plurality of (second conductor group) conductors to which the constant voltage signal VBS is applied, the drive signal COM-A or the drive is provided next to each of the one or more conductors to which the constant voltage signal VBS is applied. Any of a plurality of conductors to which the signal COM-B is applied can be arranged, and mutual interference of signals transferred through the cable 193 can be reduced in a wide range of the cable 193. Therefore, according to the liquid discharge apparatus according to this application example, it is possible to discharge liquid with high accuracy.

  Further, according to the liquid ejection apparatus 1 according to the present embodiment, among the plurality of conductors provided in the cable 193, the plurality of conductors to which the drive signal COM-A or the drive signal COM-B is applied, and the constant voltage signal VBS. The plurality of conductors to which the constant voltage signal VBS is applied and the plurality of conductors to which the drive signal COM-A or the drive signal COM-B is applied can be alternately positioned. It becomes. Therefore, mutual interference of signals transferred through the cable 193 can be reduced over a wide range of the cable 193. Therefore, according to the liquid discharge apparatus according to this application example, it is possible to discharge liquid with high accuracy.

  Further, according to the liquid ejection apparatus 1 according to the present embodiment, the magnetic field generated by the current flowing through the plurality of conductors to which the drive signal COM-A or the drive signal COM-B is applied in the plurality of conductors provided in the cable 193. And the magnetic field generated by the current flowing through the plurality of conductors to which the constant voltage signal VBS is applied cancels each other, whereby the inductance component generated in the cable 193 can also be reduced. Therefore, in the liquid ejecting apparatus 1 capable of performing serial printing on a medium having an A3 short side width or more, various problems due to the inductance component of the cable 193 can be reduced. However, when the maximum width capable of serial printing exceeds 75 inches, the total length of the cable 193 to which the drive signals COM-A and COM-B are transferred can be 3 m or more. For this reason, the impedance and inductance of the signal line through which the drive signal propagates become too large, and it is difficult to obtain the above effect. Therefore, in the liquid ejection device 1 according to the present embodiment, it is preferable that the maximum printing width (platen width PW) of serial printing is 24 inches or more and 75 inches or less.

  In the liquid ejection device 1 according to the present embodiment, the maximum printing width (platen width PW) of serial printing may correspond to any of 24 inches, 36 inches, 44 inches, and 64 inches. According to the liquid ejecting apparatus 1, excellent printing accuracy and printing stability can be realized as a 24-inch printer, a 36-inch printer, a 44-inch printer, or a 64-inch printer that is particularly in great demand.

2. Second Embodiment Hereinafter, a liquid ejection apparatus 1 according to a second embodiment will be described. In the liquid ejection device 1 of the second embodiment, contents different from those of the first embodiment will be mainly described, and description of contents overlapping with those of the first embodiment will be omitted. In the liquid ejection device 1 according to the second embodiment, the same components as those in the liquid ejection device 1 according to the first embodiment are denoted by the same reference numerals and described. In the liquid ejection device 1 according to the second embodiment, in the cable 193 that electrically connects the drive circuit unit 30 and the ejection unit 20, the drive signals COM-A and COM-B and the constant voltage signal provided in the cable 193 are provided. The number of conductors to which VBS is applied is different from that of the first embodiment.

  The configuration of the liquid ejection apparatus 1 of the second embodiment is the same as that of the first embodiment, and the description and illustration thereof are omitted (see FIG. 1). The electrical configuration of the liquid ejection apparatus 1 of the second embodiment is the same as that of the first embodiment, and the description and illustration thereof are omitted (see FIG. 2). The configuration of the ejection unit 600, the configuration of the drive signal Vout, and the configuration of the selection unit 230 of the liquid ejection apparatus 1 of the second embodiment are the same as those of the first embodiment, and the description and illustration thereof are omitted (FIGS. 3 to 11). reference). The internal configuration of the liquid ejection apparatus 1 of the second embodiment is the same as that of the first embodiment, and the description and illustration thereof are omitted (see FIG. 12).

  The configuration of the cable 193 that transfers from the drive circuit unit 30 of the second embodiment to the discharge unit 20 will be described with reference to FIGS. 17 and 18. In order to simplify the description, the cable 193 sends the drive signals COM-A1 and COM-B1 generated by the drive circuits 50-a1 and 50-b1 included in the drive circuit unit 30 to the discharge unit 20-1. The description will be made as a cable (wiring) for transfer.

  FIG. 17 is a schematic diagram illustrating the configuration of the cable 193. The cable 193 of the second embodiment is a flat flexible flat cable (FFC: Flexible Flat Cable) in which a plurality of conductors are arranged as in the first embodiment. Specifically, nine conductors 181, 182, 183, 184, 185, 186, 187, 188, and 189 are arranged in parallel on the cable 193 from the first end 195 side to the second end 196 side. ing. A plurality of signals including the drive signals COM-A1, COM-B1 and the constant voltage signal VBS are transferred to the ejection unit 20-1 through the conductors 181 to 189 arranged in parallel.

  FIG. 18 is a diagram illustrating an example of a configuration of a signal transferred by the cable 193. As shown in FIG. 18, a voltage signal VH for supplying power is applied to the conductor 181, and a voltage signal GND indicating a ground potential is applied to the conductor 189. Thus, the power for operating the discharge unit 20-1 is supplied by the potential difference between the conductor 181 and the conductor 189.

  Some of the plurality of conductors included in the cable 193 are a plurality of conductors to which the drive signals COM-A1 and COM-B1 applied to one end of the piezoelectric element 60 are applied (conductors 182 and 182 in this embodiment). 184, 186, 188, hereinafter referred to as "first conductor group"), some different one or more conductors to which a constant voltage signal VBS applied to the other end of the piezoelectric element 60 is applied. (The conductors 183, 185, and 186 in the present embodiment, which are hereinafter referred to as “second conductor group”). Specifically, the drive signal COM-A1 is applied to the conductor 182 (an example of “first conductor”) and the conductor 186 (an example of “fourth conductor”). The constant voltage signal VBS is applied to the conductor 183 (an example of “third conductor”), the conductor 185 (an example of “fifth conductor”), and the conductor 187. Further, the drive signal COM-B1 is applied to the conductor 184 (an example of the “second conductor”) and the conductor 188.

At this time, as in the first embodiment, the conductor 182 to which the drive signal COM-A1 applied to one end of the piezoelectric element 60 is applied and the constant voltage signal VBS applied to the other end of the piezoelectric element 60 are applied. The conductor 183 is an adjacent conductor, and a conductor 184 to which a drive signal COM-B1 applied exclusively to the drive signal COM-A1 is applied to one end of the piezoelectric element 60;
A conductor 183 to which a constant voltage signal VBS applied to the other end of the piezoelectric element 60 is applied is a conductor located adjacent to the other. Furthermore, in the second embodiment, the conductor 185 to which the drive signal COM-A1 applied to one end of the piezoelectric element 60 is applied, and the conductor 184 to which the constant voltage signal VBS applied to the other end of the piezoelectric element 60 is applied. Are adjacent conductors, a conductor 183 to which a drive signal COM-B1 applied to one end of the piezoelectric element 60 is applied, and a constant voltage signal VBS applied to the other end of the piezoelectric element 60 are applied. The conductor 184 is adjacent to the conductor 184.

  That is, the plurality of conductors provided in the cable 193 in the second embodiment include the voltage signal VH, the drive signal COM-A1, the constant voltage signal VBS, the drive signal COM-B1, and the constant voltage from the first end 195 side. The signal VBS, the drive signal COM-A1, the constant voltage signal VBS, the drive signal COM-B1, and the voltage signal GND are arranged in this order. In other words, in the cable 193 according to the second embodiment, the plurality of conductors included in the first conductor group and the plurality of conductors included in the second conductor group are alternately positioned. Furthermore, the conductors to which the drive signal COM-A1 and the drive signal COM-B1 are applied are alternately positioned in the first conductor group.

  Note that the cable 193 may include a plurality of conductors other than those described above, and signals other than those described above may be applied thereto. Further, the voltage signal VH and the voltage signal GND may be transferred by different cables.

  As described above, the cable 193 according to the second embodiment is applied with the two conductors to which the drive signal COM-A1 is applied, the two conductors to which the drive signal COM-B1 is applied, and the constant voltage signal VBS. Includes three conductors. In this way, by transferring the drive signal COM-A1, the drive signal COM-B1, and the constant voltage signal VBS to the discharge unit 20 via a plurality of conductors included in the cable 193, one conductor included in the cable 193 is obtained. It is possible to reduce the amount of current flowing around. Therefore, it is possible to reduce the generation of a magnetic field that is generated when a current flows through each conductor of the cable 193. Furthermore, since the amount of current flowing through each conductor of the cable 193 is reduced, the heat generation of the cable 193 can be reduced.

  Here, as in the first embodiment, a path of a current generated when the drive signal COM-A1 is applied to one end of the piezoelectric element 60 and a drive signal COM-B1 is applied to one end of the piezoelectric element 60. The path of the current generated in FIG. 19 will be described with reference to FIGS.

  FIG. 19 is a diagram illustrating a current flow when the drive signal COM-A1 is applied to the piezoelectric element 60. The dashed-dotted line shown in FIG. 19 shows the path | route of the electric current which flows into the piezoelectric element 60 from drive signal COM-A1, and the broken line shows the path | route of the electric current which flows from the piezoelectric element 60 to drive circuit 50-a1, 50-b1. In FIG. 19, four piezoelectric elements 60 included in the discharge unit 20-1 are assumed to simplify the description. In addition, the selection units 230 provided corresponding to the four piezoelectric elements 60 are all described as selecting the drive signal COM-A1.

  FIG. 19 is a diagram illustrating a current flow when the drive signal COM-A1 is applied to the piezoelectric element 60. The dashed-dotted line shown in FIG. 19 shows the path | route of the electric current which flows into the piezoelectric element 60 from drive signal COM-A1, and the broken line shows the path | route of the electric current which flows from the piezoelectric element 60 to drive circuit 50-a1, 50-b1. In FIG. 19, four piezoelectric elements 60 included in the discharge unit 20-1 are assumed to simplify the description. In addition, the selection units 230 provided corresponding to the four piezoelectric elements 60 are all described as selecting the drive signal COM-A1.

The drive signal COM-A1 output from the drive circuit 50-a1 is the conductor 1 of the cable 193.
82 and 186 are applied in parallel. The drive signals COM-A1 applied in parallel to the conductors 182 and 186 are connected to each other in the ejection unit 20-1 and applied to one end of the piezoelectric element 60 via the selection unit 230. At this time, a current flows through the conductors 182 and 186 in the direction from the drive circuit unit 30 to the discharge unit 20-1.

  The currents that flow into the piezoelectric element 60 are combined into one, then branched into three by the discharge unit 20-1, and flow in parallel through the conductors 183, 185, and 187 to which the constant voltage signal VBS is applied. That is, the conductors 183, 185, and 187 to which the constant voltage signal VBS is applied are electrically connected in the discharge unit 20-1. And it flows into each of drive circuit 50-a1 and 50-b1 which were mutually connected by the drive circuit unit 30 and were provided in the drive circuit unit 30. At this time, a current flows through each of the conductors 183, 185, and 187 from the discharge unit 20-1 to the drive circuit unit 30. In the second embodiment, as shown in FIG. 17, the conductor 182 and the conductor 183 are positioned adjacent to each other, and the conductor 186 is positioned adjacent to the conductor 185 and the conductor 187. That is, mutually opposite currents flow through the conductors 182 and 183, the conductors 185 and 186, and the conductors 186 and 187 that are adjacent to each other. As a result, the magnetic field generated by the current flowing through the conductor 182 and the magnetic field generated by the current flowing through the conductor 183 cancel each other. Further, the magnetic field generated by the current flowing through the conductor 186 and the magnetic field generated by the current flowing through the conductor 185 and the conductor 187 cancel each other. Therefore, mutual interference in the cable 193 is reduced.

  At this time, as in the first embodiment, the drive signal COM-B1 output from the drive circuit 50-b1 has the current path to the piezoelectric element 60 blocked by the selection unit 230. Therefore, no current flows through the conductor 184 and the conductor 188. Therefore, there is a possibility that the conductor 184 is subjected to mutual interference due to a magnetic field generated by current flowing through the adjacent conductors 183 and 185. In addition, the conductor 188 may be subjected to mutual interference due to a magnetic field generated by current flowing through the adjacent conductor 187. In the second embodiment, in the cable 193, the magnetic field generated by the current flowing through the conductor 183 is canceled by the magnetic field generated by the current flowing through the conductor 182. The magnetic field generated by the current flowing through the conductors 185 and 187 is canceled out by the magnetic field generated by the current flowing through the conductor 186. As a result, the drive signal COM-B1 applied to the conductors 184, 188 through which no current flows is less affected by the magnetic field generated by the current flowing through the conductors 183, 185, 187.

  FIG. 20 is a diagram illustrating a flow of current when the drive signal COM-B1 is applied to the piezoelectric element 60. A two-dot chain line shown in FIG. 20 indicates a path of current flowing from the drive signal COM-B1 to the piezoelectric element 60, and a broken line indicates a path of current flowing from the piezoelectric element 60 to the drive circuits 50-a1 and 50-b1. In FIG. 20, four piezoelectric elements 60 included in the discharge unit 20-1 are assumed to simplify the description. Further, the description will be made assuming that the selection units 230 provided corresponding to the four piezoelectric elements 60 all select the drive signal COM-B1.

  The drive signal COM-B1 output from the drive circuit 50-b1 is applied in parallel to the conductors 184 and 188 of the cable 193. The drive signals COM-B1 applied in parallel to the conductors 184 and 188 are connected to each other in the ejection unit 20-1 and applied to one end of the piezoelectric element 60 via the selection unit 230. At this time, a current flows through the conductors 184 and 188 in the direction from the drive circuit unit 30 to the discharge unit 20-1.

The currents that flow into the piezoelectric element 60 are combined into one, then branched into three by the discharge unit 20-1, and flow in parallel through the conductors 183, 185, and 187 to which the constant voltage signal VBS is applied. That is, the conductors 183, 185, and 187 to which the constant voltage signal VBS is applied are electrically connected in the discharge unit 20-1. And it flows into each of drive circuit 50-a1 and 50-b1 which were mutually connected by the drive circuit unit 30 and were provided in the drive circuit unit 30. At this time, a current flows through each of the conductors 183, 185, and 187 from the discharge unit 20-1 to the drive circuit unit 30. In the second embodiment, as shown in FIG. 17, the conductor 184 is positioned adjacent to the conductor 183 and the conductor 185, and the conductor 188 and the conductor 187 are positioned adjacent to each other. That is, mutually opposite currents flow through the conductors 184 and 185, the conductors 184 and 183, and the conductors 188 and 187 that are adjacent to each other. Thereby, the magnetic field generated by the current flowing through the conductor 184 and the magnetic field generated by the current flowing through the conductor 185 and the conductor 183 cancel each other. Also, the magnetic field generated by the current flowing through the conductor 188 and the magnetic field generated by the current flowing through the conductor 187 cancel each other. Therefore, mutual interference in the cable 193 is reduced.

  At this time, as in the first embodiment, the drive signal COM-A1 output from the drive circuit 50-a1 has the current path to the piezoelectric element 60 blocked by the selection unit 230. Therefore, no current flows through the conductor 182 and the conductor 186. Therefore, the conductor 182 may be subjected to mutual interference due to a magnetic field generated by current flowing through the adjacent conductor 183. In addition, the conductor 186 may be subjected to mutual interference due to a magnetic field generated by current flowing through the adjacent conductors 185 and 187. In the second embodiment, in the cable 193, the magnetic field generated by the current flowing through the conductors 183 and 185 is canceled by the magnetic field generated by the current flowing through the conductor 184. The magnetic field generated by the current flowing through the conductor 187 is canceled out by the magnetic field generated by the current flowing through the conductor 188. As a result, the drive signal COM-B1 applied to the conductors 184, 188 through which no current flows is less affected by the magnetic field generated by the current flowing through the conductors 183, 185, 187.

  In FIG. 19 and FIG. 20, the description has been made assuming that all of the selection units 230 provided in the discharge unit 20 select the drive signal COM-A1 (or drive signal COM-B1). Similarly to the embodiment, a part of the selection unit 230 provided in the discharge unit 20 may select the drive signal COM-A1, and a different part of the selection unit 230 may select the drive signal COM-B1.

  As described above, in the second embodiment, the drive signals COM-A1 and COM-B1 and the constant voltage signal VBS are transferred through the plurality of conductors of the cable 193 that connects the drive circuit unit 30 and the discharge unit 20. . For this reason, the amount of current flowing through one conductor of the cable 193 is reduced, and the magnetic field generated by the current flowing through each of the plurality of conductors of the cable 193 can be reduced. Therefore, it is possible to reduce mutual interference of signals transferred through the plurality of conductors of the cable 193.

  Further, in the plurality of conductors of the cable 193, the first conductor group that transfers the drive signals COM-A1 and COM-B1 and the second conductor group that transfers the constant voltage signal VBS are alternately arranged. The magnetic field generated by the current flowing through the conductor is canceled out. Therefore, mutual interference can be further reduced.

3. In the above embodiment, the drive circuit unit is electrically connected to the discharge unit mounted on the moving (reciprocating) carriage via the cable (FFC), and the drive signal is sent to the discharge unit via the cable. For example, the drive circuit unit is mounted on a carriage that moves (reciprocates) together with the discharge unit, and the drive circuit unit and the discharge unit are connected via a cable on the carriage. Alternatively, the drive signal may be transferred.

In the above embodiment, a piezoelectric large format printer in which a drive circuit drives a piezoelectric element (capacitive load) as a drive element is taken as an example. However, the present invention is a drive in which the drive circuit is a drive other than a capacitive load. It can also be applied to large format printers that drive the elements. As such a large format printer, for example, a driving circuit drives a heating element (for example, a resistor) as a driving element, and discharges liquid (ink) using bubbles generated by heating the heating element. Thermal type (bubble type) large format printers are listed.

  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 exhibits the same operational effects 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, 2 ... Main body, 3 ... Support stand, 4 ... Supply part, 5 ... Printing part, 6 ... Discharge part, 7 ... Operation part, 8 ... Ink storage part, 9 ... Ink tube, 10 ... Control unit , 19 ... Cable, 20 ... Discharge unit, 21 ... Head, 24 ... Carriage, 30 ... Drive circuit unit, 32 ... Carriage guide shaft, 33 ... Platen, 35 ... Capping mechanism, 41 ... Carriage moving mechanism, 42 ... Paper transport mechanism 50 ... Drive circuit, 60 ... Piezoelectric element, 80 ... Maintenance mechanism, 100 ... Control signal generator, 110 ... Control signal converter, 120 ... Control signal transmitter, 140 ... Drive data transmitter, 181, 182, 183 184, 185, 186, 187, 188, 189 ... conductor, 190, 191, 192, 193 ... cable, 195 ... first end, 196 ... second end, DESCRIPTION OF SYMBOLS 10 ... Selection circuit, 220 ... Selection control part, 222 ... Shift register, 224 ... Latch circuit, 226 ... Decoder, 230 ... Selection part, 232 ... Inverter, 234 ... Transfer gate, 240 ... Control signal receiving part, 250 ... Control signal Restoration unit 310 ... Drive data reception unit 600 ... Discharge unit 601 ... Piezoelectric body 611,612 ... Electrode 621 ... Vibration plate 631 ... Cavity 632 ... Nozzle plate 641 ... Reservoir 651 ... Nozzle 661 ... Supply port

Claims (10)

A first driving signal and a second driving signal are applied exclusively to one end of the driving element, and a constant voltage signal is applied to the other end of the driving element, thereby driving the driving element. A discharge unit including a discharge unit for driving and discharging liquid;
A drive circuit unit that outputs a plurality of drive signals including the first drive signal and the second drive signal;
A cable for transferring the first drive signal, the second drive signal, and the constant voltage signal to the discharge unit;
With
The cable is
A first conductor group comprising a plurality of conductors to which either the first drive signal or the second drive signal is applied;
A second conductor group composed of one or more conductors to which the constant voltage signal is applied;
Including
The first conductor group includes a first conductor to which the first drive signal is applied and a second conductor to which the second drive signal is applied,
The second conductor group has a third conductor to which the constant voltage signal is applied,
The third conductor is located adjacent to the first conductor;
The third conductor is located adjacent to the second conductor;
The number of conductors included in the second conductor group is less than the number of conductors included in the first conductor group.
A liquid discharge apparatus characterized by that. The first conductor group includes a fourth conductor to which the first drive signal is applied,
The second conductor group includes a fifth conductor to which the constant voltage signal is applied,
The fifth conductor is located adjacent to the second conductor;
The fifth conductor is located adjacent to the fourth conductor;
The liquid ejection apparatus according to claim 1, wherein The one or more conductors of the second conductor group are:
In the discharge unit, electrically connected,
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. In the cable,
Any of the plurality of conductors included in the first conductor group,
For any of the plurality of conductors included in the second conductor group,
Located on the first end side of the cable,
Any one of the plurality of conductors included in the first conductor group is:
For any of the plurality of conductors included in the second conductor group, located on the second end side of the cable,
The liquid discharge apparatus according to claim 1, wherein the liquid discharge apparatus is a liquid discharge apparatus. The number of conductors included in the second conductor group is one less than the number of conductors included in the first conductor group,
The liquid discharge apparatus according to claim 1, wherein the liquid discharge apparatus is a liquid discharge apparatus. The waveform of the first drive signal and the waveform of the second drive signal are different waveforms.
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. It is possible to perform serial printing on a medium having an A3 short side width or more.
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The maximum width capable of serial printing is not less than 24 inches and not more than 75 inches,
The liquid discharge apparatus according to claim 7. The maximum width capable of serial printing corresponds to any of 24 inches, 36 inches, 44 inches, and 64 inches.
The liquid ejecting apparatus according to claim 8. A liquid that includes a discharge unit that includes a discharge unit that discharges liquid by driving a drive element, and a drive circuit unit that outputs a plurality of drive signals including a first drive signal and a second drive signal that drive the drive element. In the discharge device, a cable for transferring the first drive signal, the second drive signal, and a constant voltage signal to the discharge unit,
A first conductor group comprising a plurality of conductors to which either the first drive signal or the second drive signal is applied;
A second conductor group composed of one or more conductors to which the constant voltage signal is applied;
Including
The first conductor group includes a first conductor to which the first drive signal is applied and a second conductor to which the second drive signal is applied,
The second conductor group includes a third conductor to which the constant voltage signal is applied,
The third conductor is located adjacent to the first conductor;
The third conductor is located adjacent to the second conductor;
The number of conductors included in the second conductor group is less than the number of conductors included in the first conductor group.
A cable characterized by that.

Images