CN115122758A

CN115122758A - Liquid discharge head, drive circuit for liquid discharge head, ink jet or 3D printer, and dispensing device

Info

Publication number: CN115122758A
Application number: CN202111542157.3A
Authority: CN
Inventors: 仁田昇
Original assignee: Toshiba TEC Corp
Current assignee: Toshiba TEC Corp
Priority date: 2021-03-25
Filing date: 2021-12-16
Publication date: 2022-09-30
Also published as: JP2022149012A

Abstract

The application provides a liquid ejection head, a driving circuit thereof, an ink jet or 3D printer and a dispensing device, which can realize the delay of driving timing between channels. The liquid ejection head driving circuit of an embodiment includes a common waveform generating section, a selecting section, and an output section. The common waveform generating unit generates a repetitive waveform having a period shorter than a driving operation section of a channel for ejecting liquid from the nozzle. The selection unit selects a section through which a part of the repetitive waveform passes. The output unit passes a part of the repetitive waveform in the selected section, and supplies the part to an electrostatic capacitive actuator that drives the channel as a drive waveform.

Description

Liquid ejection head, driving circuit for liquid ejection head, ink jet or 3D printer, and dispensing device

Technical Field

Embodiments of the present invention relate to a liquid ejection head driving circuit and a liquid ejection head.

Background

A liquid ejection head that supplies a predetermined amount of liquid to a predetermined position is known. The liquid discharge head is mounted on, for example, an ink jet printer, a 3D printer, a dispensing device, or the like. An inkjet printer ejects droplets of ink from an inkjet head to form an image or the like on a surface of a recording medium. The 3D printer forms a three-dimensional object by ejecting droplets of a modeling material from a modeling material ejection head and solidifying the droplets. The dispensing device discharges droplets of a sample and supplies the droplets to a plurality of containers or the like by a predetermined amount.

The liquid ejection head has a plurality of channels that eject liquid. Each channel includes a nozzle that ejects liquid, a pressure chamber that communicates with the nozzle, and an actuator. The liquid ejection head selects a channel for ejecting liquid from among a plurality of channels, and drives the actuator by supplying a drive signal thereto. When the actuator is driven, the volume of the pressure chamber filled with the liquid changes, and the liquid is ejected from the nozzle.

A liquid ejection head having a plurality of channels has a problem of crosstalk between channels due to pressure vibration, a problem of voltage drop due to current concentration when driving a plurality of channels, and the like, for example. As a countermeasure, for example, there is a method of shifting the driving timing between the peripheral channels. However, in order to realize the delay of the driving timing between channels, there is a problem that it is necessary to prepare a driving waveform and a wiring pattern thereof for each delay amount.

Disclosure of Invention

An object of the present invention is to provide a liquid ejection head driving circuit and a liquid ejection head that can realize a delay in driving timing between channels.

A liquid ejection head drive circuit according to an embodiment of the present invention includes a common waveform generation unit, a selection unit, and an output unit. The common waveform generating unit generates a repetitive waveform having a shorter cycle than a drive operation section of a channel through which the liquid is discharged from the nozzle. The selection unit selects a section through which a part of the repetitive waveform passes. The output unit passes a part of the repetitive waveform in the selected section and supplies the same to an electrostatic capacitive actuator that drives a channel as a drive waveform.

A liquid ejection head according to an embodiment of the present invention includes: a plurality of channels each having a nozzle and an actuator that eject liquid; a liquid supply unit that supplies liquid to the channel; and the liquid ejection head drive circuit.

An ink jet printer according to an embodiment of the present invention forms an image on a surface of a recording medium, and is mounted with the liquid ejection head.

The 3D printer according to the embodiment of the present invention forms a three-dimensional object, and is mounted with the liquid ejection head.

The dispensing device according to the embodiment of the present invention supplies a predetermined amount of sample to a plurality of containers, and is mounted with the liquid discharge head.

Drawings

Fig. 1 is an overall configuration diagram of an inkjet printer including an inkjet head according to an embodiment.

Fig. 2 is a perspective view of the ink jet head.

Fig. 3 is a sectional view of the actuator of the ink jet head.

Fig. 4 is a block configuration diagram of an inkjet head driving circuit according to an embodiment.

Fig. 5 is a detailed view of a selection driving circuit in the head driving circuit.

Fig. 6 is a detailed diagram of a selection circuit in the above-described selection drive circuit.

Fig. 7 is a timing chart of the operation of the head driving circuit.

Fig. 8 is a timing chart of the operation of the ink jet head driving circuit.

Description of the reference numerals

10 an ink jet printer; 100 to 103 ink jet heads; 2 a nozzle head; 25, a nozzle; 31 a drive IC; 5 an actuator; a 51 pressure chamber; 52 an air chamber; 6 ink jet head driving circuit; 61 a common waveform generating section; 62 a timing generation unit; 63 an image generating section; 64 select drive circuit; 7 a selection unit; 71 switch.

Detailed Description

Hereinafter, a liquid ejection head according to an embodiment will be described in detail with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals.

An ink jet printer 10 that prints an image on a recording medium will be described as an example of an image forming apparatus having a liquid ejection head according to an embodiment mounted thereon. Fig. 1 shows a schematic configuration of an inkjet printer 10. The inkjet printer 10 includes: a cassette 12 that stores a sheet S as an example of a recording medium; an upstream conveying path 13 for the sheet S; a conveyor belt 14 that conveys the sheet S taken out of the cassette 12; a plurality of ink jet heads 100 to 103 that eject droplets of ink toward the sheet S on the conveyor belt 14; a downstream conveying path 15 for the sheet S; a discharge tray 16; and a control substrate 17. An operation unit 18 as a user interface is disposed on the upper side of the housing 11.

The image data printed on the sheet S is generated by, for example, a computer 200 as an external connection device. The image data generated by the computer 200 is sent to the control board 17 of the ink jet printer 10 via the cable 201 and the

connectors

202 and 203.

The pickup roller 204 feeds the sheets S one by one from the cassette 12 to the upstream conveying path 13. The upstream conveying path 13 is constituted by the pair of

feed rollers

131, 132 and

sheet guide plates

133, 134. The sheet S is sent to the upper surface of the conveying belt 14 via the upstream conveying path 13. An arrow 104 in the figure shows a conveying path of the sheet S from the cassette 12 to the conveying belt 14.

The conveyor belt 14 is a mesh endless belt having a plurality of through holes formed in the surface thereof. The conveying belt 14 is rotatably supported by 3 rollers, i.e., the driving roller 141 and the driven

rollers

142 and 143. The motor 205 rotates the driving roller 141 to rotate the conveying belt 14. The motor 205 is an example of a driving device. The direction of rotation of the conveyor belt 14 is shown at 105 in the figure. A negative pressure tank 206 is disposed on the back side of the conveyor belt 14. The negative pressure tank 206 is connected to a fan 207 for reducing pressure. The fan 207 generates a negative pressure in the negative pressure container 206 by the generated air flow, and causes the sheet S to be sucked and held on the upper surface of the transport belt 14. The flow of the gas stream is shown at 106.

The ink jet heads 100 to 103, which are examples of liquid ejection heads, are disposed so as to face the sheet S sucked and held on the conveying belt 14 with a small gap of, for example, 1 mm. The inkjet heads 100 to 103 eject droplets of ink onto the sheet S. The inkjet heads 100 to 103 print images when the sheet S passes below. The ink jet heads 100 to 103 have the same configuration except that the colors of the ejected inks are different. The color of the ink is, for example, cyan, magenta, yellow, and black.

The ink jet heads 100 to 103 are connected to ink tanks 315 to 318 and ink supply pressure adjusting devices 321 to 324 through ink flow paths 311 to 314, respectively. Each ink tank 315 to 318 is disposed above each ink jet head 100 to 103. In the standby state, the ink supply pressure adjusting devices 321 to 324 adjust the inside of the ink jet heads 100 to 103 to a negative pressure, for example, -1.2kPa, with respect to the atmospheric pressure so that ink does not leak from the nozzles 25 (see FIG. 2) of the ink jet heads 100 to 103. When forming an image, the ink in each ink tank 315 to 318 is supplied to each ink jet head 100 to 103 through the ink supply pressure adjusting devices 321 to 324.

After the image is formed, the sheet S is conveyed from the conveying belt 14 to the downstream conveying path 15. The downstream conveying path 15 is constituted by pairs of

feed rollers

151, 152, 153, 154 and

sheet guide plates

155, 156 that define a conveying path of the sheet S. The sheet S is conveyed from the discharge port 157 to the discharge tray 16 via the downstream conveying path 15. An arrow 107 in the figure illustrates a conveying path of the sheet S.

Next, the structure of the ink jet heads 100 to 103 will be explained. The ink jet head 100 will be described below with reference to fig. 2 to 3, but the ink jet heads 101 to 103 have the same configuration as the ink jet head 100.

As shown in fig. 2, the ink jet head 100 includes a nozzle head 2 as an example of a liquid ejecting section and a flexible printed wiring board 3 as an example of a printed wiring board. The nozzle head 2 includes: the ink jet head includes a nozzle plate 21, an actuator substrate 22, a sealing member 23 for sealing openings of pressure chambers 51 and air chambers 52 formed in the actuator substrate 22, and an ink supply port 24 formed in the sealing member 23. The ink supply port 24 is connected to an ink supply pressure adjusting device 321 of fig. 1 via an ink flow path 311.

The flexible printed wiring board 3 is connected to the actuator substrate 22 of the nozzle head 2 and the print substrate 4 as a relay substrate. The flexible printed wiring board 3 is mounted with a driving IC (Integrated Circuit) 31 (hereinafter, referred to as a driving IC) as a driver chip. The drive IC31 temporarily stores print data transmitted from the control board 17 of the ink jet printer 10 via the print board 4, and supplies a drive signal to each channel to eject ink at a predetermined timing.

The nozzle plate 21 is a rectangular plate formed of resin such as polyimide or metal such as stainless steel, for example. A plurality of nozzles 25 for ejecting ink are formed on the surface of the nozzle plate 21. The nozzle density is set to be, for example, in the range of 150 to 1200 dpi.

The actuator substrate 22 is, for example, a rectangular substrate formed of an insulating ceramic. As shown in fig. 3, a plurality of ink pressure chambers 51 and air chambers 52 are alternately formed in the actuator substrate 22 along a first direction, for example, the X direction. The pressure chamber 51 communicates with the nozzle 25. The pressure chamber 51 communicates with the ink supply port 24 via, for example, a common ink chamber (not shown) formed in the actuator substrate 22 or the sealing member 23. That is, the nozzle head 2 supplies ink to the pressure chambers 51 of the respective channels through the ink supply ports 24. That is, the nozzle head 2 serves as both the liquid ejecting section and the liquid supplying section. On the other hand, the air chamber 52 disposed adjacent to the pressure chamber 51 is a closed space not communicating with the nozzle 25 and the common ink chamber (not shown). The pressure chamber 51 and the air chamber 52 are formed on the actuator substrate 22 by, for example, cutting 2 pieces of

piezoelectric members

26 and 27 stacked in a direction opposite to the polarization direction (for example, an opposing direction) into, for example, a rectangular groove shape in a second direction, for example, the Z direction. That is, the pressure chamber 51 and the air chamber 52 are partitioned by the

piezoelectric members

26 and 27 stacked in the third direction, for example, the Y direction, as side walls.

The electrodes 53 are integrally formed on the bottom surface and both side surfaces of the pressure chamber 51. The electrode 53 of the pressure chamber 51 is connected to a separate wiring 54 as a wiring member. Electrodes 55 are integrally formed on the bottom surface and both side surfaces of the air chamber 52. The electrode 55 of the air chamber 52 is connected to a common wiring 56 as a wiring member. That is, the connection point of the electrode 53 of the pressure chamber 51 and the individual wiring 54 is one terminal of the actuator 5. The connection point of the electrode 55 of the air chamber 52 and the common wiring 56 is the other terminal of the actuator 5. The

electrodes

53 and 55, the individual wiring 54, and the common wiring 56 are formed of, for example, a nickel thin film. The individual wiring 54 is connected to a drive IC31 (i.e., a drive circuit of each channel). The drive IC31 supplies a drive voltage as a drive signal to each channel of the actuator 5. The voltage V1 and the voltage V2 are supplied to the driving IC31 as power sources of driving voltages. The common wiring 56 is, for example, Grounded (GND). With this configuration, an electric field is applied to the actuator 5 to which a drive voltage is applied in a direction intersecting (preferably orthogonal to) the polarization axes of the

piezoelectric members

26 and 27, and the

piezoelectric members

26 and 27 as the X-direction side walls of the actuator 5 are symmetrically deformed in the X-direction in a shear (shear) mode.

That is, the ink pressure chamber 51 is formed by being sandwiched between the pair of columnar actuators 5 using the

piezoelectric members

26 and 27. The actuator 5 is deformed by applying a potential difference to both walls of the columnar actuator 5, that is, the inner wall and the outer wall of the pressure chamber 51, and charging/discharging the electrostatic capacitive actuator 5 using the

piezoelectric members

26 and 27. As a result, the volume of the pressure chamber 51 changes, and as a result, the ink pressure in the pressure chamber 51 changes. By adjusting the magnitude and timing of this change, ink is ejected from the nozzles 25.

Fig. 4 is a block configuration diagram of the head drive circuit 6 in the drive IC 31. The inkjet head drive circuit 6 includes a common waveform generation unit 61, a timing generation unit 62, an image generation unit 63, and a selection drive circuit 64.

The common waveform generating unit 61 generates a repetitive waveform described in detail later as a common waveform. The common waveform is sent to the selection drive circuit 64. The timing generator 62 sends a waveform passing pulse and a group selection signal to the selection drive circuit 64, and synchronizes with the timings of the operations of the common waveform generator 61 and the image generator 63. The image generating section 63 generates image data for each channel and sends it to the selection driving circuit 64. The image data generated for each channel includes information on whether ink is ejected from the channel and the gradation of dots formed when ink is ejected.

As shown in fig. 5, the detailed circuit configuration of the selection drive circuit 64 includes a selection unit 7 and an output unit for each channel (ch1 to ch N). The selection unit 7 is a selection circuit such as a selector. An example of the selection circuit is a 1-out-of-8 selection circuit. The output unit is, for example, a switch 71. An example of the switch 71 is a CMOS analog switch. The image data (ch1 image to ch N image) from the image generator 63 is input to the selector 7 of the corresponding channel. The waveform from the timing generator 62 is input to the selector 7 of each channel by a pulse and a group selection signal. The selection unit 7 selects one of the prepared waveform passage pulses based on the image data and the group selection signal. Then, the selection unit 7 outputs a pass signal based on the selected waveform pass pulse. The ON/OFF (ON/OFF) of the switch 71 is controlled by a signal. While the switch 71 is on, the common waveform supplies a drive voltage to the actuator 5 through the switch 71. That is, a part of the common waveform is supplied to the actuator 5 as a drive waveform through the switch 71.

As an example, the selection unit 7 uses an 8-out-of-1 selection circuit shown in fig. 6. The input b0 and the input b1 of the input image data are supplied with signals of, for example, 2 bits, respectively. For example, when ink is not ejected, a signal of "0, 0" is supplied to the input b0 and the input b1, a signal of "1, 0" is supplied to a dot with a low gray scale, and a signal of "1, 1" is supplied to a dot with a high gray scale. The group select signal that assigns the channel to which of the a or B groups is provided to input B2. For example, a 1-bit signal of "1" is supplied in the case of the a group, and a 1-bit signal of "0" is supplied in the case of the B group. Waveforms described in detail later are supplied to the inputs a0 to A3 and the inputs B0 to B3 of the 8-out-of-1 selection circuit by pulses, respectively. The 1-out-of-8 selection circuit as the selection unit 7 selects one of the plurality of waveform passing pulses based on the respective signals supplied to the inputs b0 to b 2. Then, a pass signal based on the selected waveform pass pulse is output and supplied to the switch 71.

As shown in the timing chart of fig. 7, the common waveform includes a first drive waveform element constituting the pull-pulse part and a second drive waveform element constituting the cancel-pulse part. The first drive waveform element and the second drive waveform element are respectively formed by repeating triangular waves at the change part of the charge-discharge waveform. As an example, when the voltage V1 is a positive voltage, the voltage V2 is a negative voltage, and the voltage V3 is 0V (GND), the first drive waveform element constituting the pull pulse unit is a triangular wave that oscillates between the negative voltage V2 and the voltage V3 (0V), and the second drive waveform element constituting the cancel pulse unit is a triangular wave that oscillates between the voltage V3 (0V) and the positive voltage V1. The repeating cycle of the triangular wave is set to a cycle shorter than the driving operation interval of the channel for ejecting ink. Preferably, the period is shorter than the driving operation interval for ejecting 1 drop of ink. More preferably, the period is shorter than the drive operation interval of the traction pulse unit including no cancellation pulse unit. Therefore, in the case of the multi-drop method in which 1 dot is formed by the total number of multiple drops, the period is set to be shorter than the drive operation interval in which 1 drop of ink is discharged. A preferred example of the repetition period of the triangular wave is 1 MHz. I.e. a triangular wave rising at 500ns and falling at 500 ns.

With respect to the waveform passing pulse, various pulse trains are prepared in each of the group a and the group B. The burst of group a is waveform A3 pass pulse and waveform a1 pass pulse shown in fig. 7. Each of the pulses is supplied to, for example, inputs a1 and A3 of the 1-out-of-8 selection circuit of fig. 6, respectively, and the selector 7 selects one of them as described above. Likewise, the burst of group B is the waveform B3 pass pulse and the waveform B1 pass pulse shown in fig. 7. Each of the pulses is supplied to, for example, the inputs B1 and B3 of the 1-out-of-8 selection circuit of fig. 6, respectively, and the selector 7 selects one of them as described above. It should be noted that the 1-out-of-8 selection circuit can select 4 kinds of pulse trains in each of the group a and the group B. The timing chart of fig. 7 illustrates two kinds of the pass pulses (waveforms A3, B3) in which the dots of high gradation are formed and the pass pulses (waveforms a1, B1) in which the dots of low gradation are formed. The width and interval of the pulses are different from each other with respect to a plurality of waveforms within the same group by the pulses. The pulse width and the interval of the waveform a3 passing pulse and the waveform B3 passing pulse, which form the dots of the high gradation, are the same, but the drive timings are in a delayed relationship with each other because they are different groups. The same applies to the waveform a1 passing pulse and the waveform B1 passing pulse, which form the dots of the low gradation. On the other hand, the waveform A3 passing pulse and the waveform a1 passing pulse of the same group have no delay in the drive timing, but the widths of the pulses are different. By changing the pulse width in this way, the driving voltage can be adjusted. The same is true for waveform B3 through pulse and waveform B1 through pulse for group B.

Next, the operation of the head drive circuit 6 will be described with reference to fig. 5 and 7 in particular. In the following description, an operation of assigning odd-numbered channels (ch1, 3 … … n-1) to group a and even-numbered channels (ch2, 4 … … n) to group B and driving them will be described as an example. Further, as an example, it is assumed that the channel 1(ch1) and the channel 2(ch2) print dots of high gradation, the channel 3(ch3) and the channel 4(ch4) print dots of low gradation, and the channel 5(ch5) does not print.

The common waveform generator 61 generates a triangular wave as a repetitive waveform and sends it to the selection drive circuit 64. The image generating section 63 generates image data for each channel based on data sent from the control board 17 of the ink jet printer 10, and sends the image data to the selection drive circuit 64. The timing generator 62 synchronizes the timings of the operations of the common waveform generator 61 and the image generator 63, and sends a waveform to the selection drive circuit 64 by a pulse and a group selection signal.

The selection unit 7 of each channel selects a waveform passing pulse based on the image data and the group selection signal. For example, for channel 1(ch1), a signal for selecting group a is supplied to the input b2, and signals for forming dots of high gradation are supplied to the input b0 and the input b 1. Thereby, the selector 7 of the channel 1(ch1) selects the waveform A3 passing pulse which forms a dot with a high gradation at the drive timing of the group a.

The selection unit 7 supplies a passing signal of a passing pulse according to the selected waveform a3 to the switch 71 as an output unit. When the waveform a3 passes through the pulse, the pulse starts (ON) at a part of the falling edge of the triangular wave in the section of the first drive waveform element constituting the pull-pulse section, and the switch 71 is turned ON (ON). During the pulse start, the switch 71 remains on, and the actuator 5 is negatively charged toward the voltage V2. Thereby, both side walls of the pressure chamber 51 are deformed outward, and the volume of the pressure chamber 51 is expanded. After that, the pulse is turned OFF (OFF) and the switch 71 is turned OFF (OFF), but even if the switch 71 is turned OFF, the electrostatic capacitive actuator 5 maintains the voltage of the drive waveform at the moment when the switch 71 is turned OFF. Next, at the rising edge of the triangular wave, the pulse is turned on, and the switch 71 is turned on. While the pulse is on, the switch 71 is kept on, and the actuator 5 is discharged. The actuator 5 deformed outward is restored by the discharge, and the expanded pressure chamber 51 is contracted to the original volume, and the ink is discharged from the nozzle 25.

Next, in the section of the second drive waveform element constituting the cancellation pulse unit, the pulse is turned on at the part of the rising edge of the triangular wave, and the switch 71 is turned on. During the pulse-on period, the switch 71 remains on, and the actuator 5 is positively charged toward the voltage V1. By this charging, both side walls of the pressure chamber 51 are deformed inward, and the volume of the pressure chamber 51 is contracted. By this contraction, the residual vibration is damped. Next, the pulse is turned on at a part of the falling edge of the triangular wave, and the switch 71 is turned on. During the pulse-on period, the switch 71 remains on, and the actuator 5 is discharged. When the actuator 5 is repeatedly driven, for example, a flat portion may be formed at a voltage V3(═ 0V) after the second drive waveform element, and the pulse may be turned on to reset (discharge) the actuator 5 to 0V. In this way, the channel 1(ch1) passes a part of the repetitive waveform which is the common waveform, and is driven by the waveform A3 which is the drive waveform.

Similarly, channel 2(ch2) is driven by waveform B3. However, the channel 2(ch2) belonging to the group B is driven with a delay with respect to the channel 1(ch1) belonging to the group a. When the period of the triangular wave is, for example, 1MHz, the group B is driven with a delay amount of 1000ns in the time chart of fig. 7. That is, in the present embodiment, a plurality of channels are grouped, simultaneous driving is allowed in the same group, and simultaneous driving is avoided in different groups. By delaying the channels in this manner, crosstalk due to pressure vibration can be suppressed. The reason for grouping in odd and even numbers is that crosstalk between adjacent channels is the largest. Crosstalk between channels is effective in terms of crosstalk via an ink flow path, crosstalk due to mechanical coupling, electrical coupling (crosstalk due to common impedance, etc.), and the like. Further, voltage drop due to current concentration when the plurality of channels are driven simultaneously can be suppressed. However, although grouping is preferably performed by odd-numbered and even-numbered, the present invention is not limited to this. Which channel is divided into which group can be freely set by the group selection signal from the timing generation section 62. Of course, the number of groups is not limited to 2 groups a and B, and may be 3 or more.

Similarly, the channel 3(ch3) is driven by the waveform a 1. Since the pulse width of the waveform a1 passing pulse is made shorter than that of the waveform A3 passing pulse, the capacity of the pressure chamber 51 changes less corresponding to a shorter charge/discharge time of the actuator. That is, the amount of ink ejected from the nozzles 25 is reduced to print dots with low gradation. Similarly, the channel 4(ch4) is also driven at the driving timing of the group B in accordance with the waveform B1, and dots of low gradation are printed.

For the channel 5(ch) not ejecting ink, for example, a pulse (not shown) is supplied with the waveform a0 without pulse. Similarly, in the group B, a pulse (not shown) having a waveform B0 without pulse is supplied to a channel not ejecting ink. As a modification, in the case of performing the pilot operation, that is, in the case where it is necessary to supply the micro-vibration to the actuator 5 of the channel which does not discharge the ink, as shown in fig. 8, the waveform a0 of the short pulse width which is driven at the low voltage which does not discharge the ink may be supplied only in the section of the second driving waveform element, and the pulse may be transmitted by the pulse/waveform B0. That is, both the drive waveform for ejecting ink and the waveform for applying micro-vibration without ejecting ink can be generated from a repeating waveform such as a triangular wave.

According to the above embodiment, the common waveform using the repetitive waveform is formed, and each channel ejecting ink passes a part of the common waveform as the drive waveform, so that the delay of the drive timing between channels can be realized without preparing the drive waveform and its wiring pattern for each delay amount, for example.

As a modification of the triangular wave, the period of the triangular wave may be different between the sections of the first drive waveform element and the second drive waveform element. In addition, the amplitudes of the triangular waves of the first drive waveform element and the second drive waveform element may be made the same. The triangular wave is exemplified as a preferable example of the common waveform, but is not limited to the triangular wave. For example, it may be a repeating waveform in the form of an exponential function. In addition, the drive waveform of the pulling is given as an example, but a drive waveform other than the pulling may be used. Further, a drive waveform of a plurality of droplets may be used.

The inkjet head 100 is not limited to the shear mode type actuator 5 in which the pressure chambers 51 and the air chambers 52 are alternately arranged. For example, a plurality of nozzles 25 and actuators 5 may be arranged on the surface of the nozzle plate 21. Other drop-on-demand piezoelectric actuators 5 are also possible.

In the above embodiment, the inkjet head 100 of the inkjet printer 10 was described as an example of the liquid discharge device, but the liquid discharge device may be a modeling material discharge head of a 3D printer or a sample discharge head of a dispensing device.

The embodiments of the present invention are presented by way of example and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various forms, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications are included in the scope and spirit of the invention, and are also included in the invention described in the claims and their equivalent scope.

Claims

1. A liquid ejection head drive circuit comprising:

a common waveform generating unit that generates a repetitive waveform having a period shorter than a drive operation section of a channel through which a liquid is ejected from a nozzle;

a selection unit that selects a section through which a part of the repetitive waveform passes; and

and an output unit that passes a part of the repetitive waveform in the section selected by the selection unit and supplies the same to the electrostatic capacitive actuator of the channel as a drive waveform.

2. A liquid ejection head drive circuit according to claim 1,

a plurality of waveform passing pulses having different sections through which a part of the repetitive waveform passes are prepared in advance, and the selection unit selects one of the waveform passing pulses to select the section through which the part of the repetitive waveform passes.

3. A liquid ejection head drive circuit according to claim 2,

the selection unit selects the waveform passing pulse according to image data.

4. A liquid ejection head drive circuit according to claim 2,

the channels are classified into any one of a plurality of groups,

the selection unit selects the waveform passing pulse according to which group the channel is assigned to.

5. A liquid ejection head drive circuit according to claim 1,

the common waveform generating unit generates a triangular wave as the repetitive waveform.

6. A liquid ejection head drive circuit according to any one of claims 1 to 5,

the selection unit is a selection circuit, and the output unit is a switch.

7. A liquid ejecting head is provided with:

a plurality of channels each having a nozzle and an actuator that eject a liquid;

a liquid supply unit that supplies liquid to the channel; and

a liquid ejection head drive circuit according to any one of claims 1 to 6.

8. An ink jet printer for forming an image on a surface of a recording medium, the ink jet printer being equipped with the liquid ejection head according to claim 7.

9. A3D printer for forming a three-dimensional object, characterized in that,

the 3D printer is mounted with the liquid ejection head according to claim 7.

10. A dispensing device for supplying a predetermined amount of a sample to a plurality of containers, the dispensing device being mounted with the liquid discharge head according to claim 7.