Drive unit for liquid dispensing head

Abstract

To provide a drive device for a liquid dispensing head that can be driven in a multi-drop manner with a simple circuit configuration. [Solution] The liquid discharge head drive device according to the embodiment drives an actuator that drives a pressure chamber communicating with a nozzle that discharges liquid using a multidrop waveform which comprises one or more of a plurality of discharge waveforms, including a first discharge waveform that discharges liquid, a second discharge waveform that has a lower discharge efficiency than the first discharge waveform, a third discharge waveform which is composed of a part of the first discharge waveform, and a fourth discharge waveform which is composed of a part of the second discharge waveform.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a drive device for a liquid discharge head. [Background Art]

[0002] As a liquid discharge apparatus, an inkjet head mounted in an inkjet printer is known. The inkjet printer discharges ink droplets from an inkjet head to form an image or the like on the surface of a recording medium. The inkjet head changes the volume of a pressure chamber by means of a piezoelectric actuator, thereby discharging ink droplets from a nozzle communicating with the pressure chamber. The operation of the actuator is controlled by a drive waveform input to the actuator.

[0003] Multi-drop driving is known as one of the discharge control methods for inkjet heads. The waveform for multi-drop driving is a waveform that repeats the expansion, steady state, contraction, and steady state operations of the actuator. The number of droplets can be adjusted and the volume of the droplets can be controlled according to the number of repeated discharge operations.

[0004] For example, when the discharge waveform for discharging one droplet is a drop waveform having one positive pulse and one negative pulse respectively, the discharge waveform for discharging a plurality of droplets is a waveform that sequentially includes this basic drop waveform corresponding to the number of droplets to be discharged. [Prior Art Document] [Patent Document]

[0005] [Patent Document 1] US Patent Application Publication No. 2006-0028497 Specification [Summary of the Invention] [Problem to be Solved by the Invention]

[0006] The problem that this invention aims to solve is to provide a drive device for a liquid discharge head that can be driven in a multi-drop manner with a simple circuit configuration. [Means for solving the problem]

[0007] The liquid discharge head drive device according to the embodiment drives an actuator that drives a pressure chamber communicating with a nozzle that discharges liquid using a multidrop waveform comprising one or more of a plurality of discharge waveforms, including a first discharge waveform that discharges liquid, a second discharge waveform with lower discharge efficiency than the first discharge waveform, a third discharge waveform which is composed of a part of the first discharge waveform, and a fourth discharge waveform which is composed of a part of the second discharge waveform. [Brief explanation of the drawing]

[0008] [Figure 1] An explanatory diagram showing the configuration of a liquid dispensing device according to the first embodiment. [Figure 2] A perspective view showing the configuration of the liquid dispensing head. [Figure 3] A cross-sectional view showing part of the configuration of the liquid dispensing head. [Figure 4] Diagram illustrating the drive circuit of the liquid dispensing head. [Figure 5] An explanatory diagram showing the drive waveform according to the embodiment. [Figure 6] An explanatory diagram showing the waveforms and vibration analysis results of the first and third discharge waveforms. [Figure 7] An explanatory diagram showing the waveforms and vibration analysis results of the second and fourth discharge waveforms. [Figure 8] An explanatory diagram showing the drive waveform according to the first embodiment. [Figure 9] An explanatory diagram showing the drive waveform for the comparative example. [Figure 10] An explanatory diagram showing drive waveforms according to another embodiment. [Figure 11] An explanatory diagram showing drive waveforms according to another embodiment. [Modes for carrying out the invention]

[0009] The liquid discharge head 10 and liquid discharge device 100 according to the first embodiment will be described below with reference to Figures 1 to 8. Figure 1 is a block diagram showing the configuration of the liquid discharge device 100 according to the first embodiment. Figure 2 is a perspective view showing the configuration of the liquid discharge head, and Figure 3 is a cross-sectional view showing the configuration of the actuator of the liquid discharge head. Figure 4 is an explanatory diagram showing the configuration of the drive circuit. In each figure, the configuration is shown enlarged, reduced, or omitted as appropriate for explanatory purposes.

[0010] As shown in Figure 1, the liquid dispensing device 100 includes a liquid dispensing head 10, a liquid supply unit 21, a transport unit 22, an operation unit 25, a display unit 26, and a control unit 30.

[0011] The liquid ejection device 100 is an inkjet printer that performs image formation processing on a medium such as paper by ejecting a liquid such as ink from the liquid ejection head 10 while transporting the medium, such as paper, along a predetermined transport path that passes through a printing position opposite the liquid ejection head 10.

[0012] The liquid ejection head 10 is, for example, a shear-mode, sheared-wall type inkjet head. The liquid ejection head 10 may be a non-circulating head that does not circulate ink, or it may be a circulating head that circulates ink. In this embodiment, the liquid ejection head 10 will be described using an example of a non-circulating head.

[0013] For example, the liquid discharge head 10 includes an actuator 11 having a plurality of piezoelectric elements communicating with a nozzle, and a drive circuit 12 (drive device) that drives the actuator 11.

[0014] As shown in Figures 2 and 3, for example, the liquid discharge head 10 has a flow path that includes a plurality of nozzles 111 for discharging liquid, a plurality of pressure chambers 112 communicating with the nozzles, and a common chamber communicating with the plurality of pressure chambers 112. The flow path of the liquid discharge head 10 is connected to a liquid supply unit 21, and ink is supplied from the liquid supply unit to the flow path of the liquid discharge head 10.

[0015] The actuator 11 is, for example, an actuator plate formed in a plate shape from a piezoelectric member, and includes a plurality of piezoelectric elements 115 and electrodes 116 formed on the piezoelectric elements 115. For example, groove-shaped pressure chambers 112 are formed between the plurality of piezoelectric elements 115. The actuator 11 applies pressure to ink in the pressure chambers 112 to eject the ink from nozzles by applying a voltage to the electrodes 116 of the piezoelectric elements 115 provided corresponding to each pressure chamber 112, which deforms the piezoelectric elements 115.

[0016] The drive circuit 12 drives the actuator 11 by applying a drive voltage to the electrodes of the piezoelectric body. The drive circuit 12 generates control signals and drive signals for operating the piezoelectric elements 115. For example, the drive circuit 12 generates control signals for control such as selecting the timing of ejecting liquid and the piezoelectric elements 115 that eject liquid in accordance with image signals input from the control unit 30 of the liquid ejecting apparatus 100. Further, the drive circuit 12 generates a voltage to be applied to the electrodes 116 of the piezoelectric elements 115 in accordance with the control signals, that is, a drive signal (electric signal). When the drive circuit 12 applies a drive signal to the piezoelectric elements 115, the piezoelectric elements 115 are driven to change the volume of the pressure chambers 112. That is, the actuator 11 is configured to be drivable and controllable under the control of the control unit 30.

[0017] As shown in FIG. 1, the drive circuit 12 includes a data buffer 13, a decoder 14, and a driver 15. The data buffer 13 stores print data in time series for each piezoelectric element of the actuator 11. The decoder 14 controls the driver 15 for each piezoelectric element based on the print data stored in the data buffer 13. The driver 15 outputs drive signals for operating each piezoelectric element 115 based on control from the decoder 14. The drive signal is a voltage applied to the electrode 116 of each piezoelectric element 115.

[0018] The liquid supply unit 21 is connected to the primary side of the flow path of the liquid discharge head 10, and supplies liquid to the flow path of the liquid discharge head 10. For example, the liquid supply unit 21 includes a tank that stores liquid, a connection flow path that connects the tank and the liquid discharge head 10, and a liquid feed pump that sends the liquid in the tank to the liquid discharge head 10.

[0019] The conveyance unit 22 conveys a medium such as paper along a predetermined conveyance path and supplies it to a printing position. The conveyance unit 22 includes, for example, a plurality of conveyance rollers and conveyance guides arranged along the conveyance path. The conveyance unit 22 supports the medium so as to be relatively movable with respect to the liquid discharge head 10.

[0020] The operation unit 25 includes function keys such as a power key, a paper feed key, and an error reset key, for example.

[0021] The display unit 26 has a display capable of displaying various states of the image printing apparatus.

[0022] The control unit 30 is, for example, a control board, and includes a processor 31, a ROM (Read Only Memory) 32, a RAM (Random Access Memory) 33, an image memory 34, and an I / O port 35 which is an input / output port.

[0023] The processor 31 is a processing circuit such as a CPU (Central Processing Unit) serving as a controller. The processor 31 corresponds to a central part of a computer. The processor 31 controls each unit to implement various functions as a printer in accordance with an operating system and application programs. For example, the processor 31 controls operations of the liquid discharge head 10, the liquid supply unit 21, and the conveyance unit 22 provided in the liquid discharge apparatus 100. Further, during printing, the processor 31 transmits print data stored in the image memory 34 to the drive circuit 12 in drawing order.

[0024] ROM32 corresponds to the read-only main memory portion of the computer described above. ROM32 stores the operating system and application programs. ROM32 may also store data necessary for the processor 31 to perform operations to control various components.

[0025] RAM33 corresponds to the rewritable main memory portion of the computer described above. RAM33 stores the data necessary for the processor 31 to execute processing. RAM33 is also used as a work area, where information is rewritten as needed by the processor 31. The work area may include image memory where print data is displayed.

[0026] The image memory 34 stores, for example, print data from an externally connected device 200.

[0027] The I / O port 35 is an interface unit that inputs data from the externally connected device 200 and outputs data to the outside. Print data from the externally connected device 200 is transmitted to the control unit 30 via the I / O port 35 and stored in the image memory 34.

[0028] In the liquid dispensing device 100 configured in this way, the control unit 30 inputs a signal to the liquid dispensing head 10, which causes the drive circuit 12 to apply a drive voltage, generating a potential difference in multiple piezoelectric elements 115, selectively deforming the piezoelectric elements 115, and increasing or decreasing the volume of the pressure chamber 112, thereby dispensing liquid from the nozzle 111. For example, when the volume of the pressure chamber 112 expands or contracts during operation, pressure oscillations occur within the pressure chamber 112. These pressure oscillations increase the pressure within the pressure chamber 112, causing ink droplets to be dispensed from the nozzle 111 communicating with the pressure chamber 112. For example, a signal input from the control unit 30 causes the drive circuit 12 to apply a drive voltage to the electrodes of the pressure chamber 112 via the electrode 116, generating a potential difference in multiple piezoelectric elements 115, selectively deforming the piezoelectric elements 115, and changing the volume of the pressure chamber 112. For example, when an expansion voltage is applied, the piezoelectric element 115 deforms, increasing the volume of the corresponding pressure chamber 112 and decreasing the pressure, causing ink from the common chamber to flow into the pressure chamber 112. Then, with the volume of the pressure chamber 112 increased, when a reverse potential driving voltage is applied to the electrode 116 of the piezoelectric element 115, the piezoelectric element 115 deforms, decreasing the volume of the pressure chamber 112 and increasing the pressure. As a result, the ink in the pressure chamber 112 is pressurized and ejected from the nozzle 111.

[0029] The drive waveform generated by the drive signal in the drive circuit 12 of the liquid discharge head 10 will be explained with reference to Figures 4 to 8.

[0030] For example, as shown in Figure 4, the drive circuit 12 includes a waveform generation circuit 121, a first waveform extraction circuit 122, and a second waveform extraction circuit 123. The waveform generation circuit 121 generates the base drive waveforms, the first discharge waveform and the second discharge waveform, and sends them to the first waveform extraction circuit 122. The first waveform extraction circuit 122 extracts four types of waveforms, the first discharge waveform, the second discharge waveform, the third discharge waveform, and the fourth discharge waveform, from the waveform extraction information and the base drive waveforms, the first discharge waveform and the second discharge waveform, and sends them to the second waveform extraction circuit 123. The second waveform extraction circuit 123 generates drive waveforms to be input to each actuator based on the four types of waveforms, the first discharge waveform, the second discharge waveform, the third discharge waveform, and the fourth discharge waveform, and the printed data.

[0031] Figure 5 is an explanatory diagram showing the drive waveforms for 1-drop, 2-drop, and 3-drop ejection in Example 1 of this embodiment. Figure 6 is a waveform diagram showing the first and third ejection waveforms, and Figure 7 is a waveform diagram showing the second and fourth ejection waveforms. In each waveform diagram, the horizontal axis represents time, and the vertical axis represents voltage, ink flow rate, and ink pressure. In each figure, voltage is shown by a solid line, flow rate at the nozzle surface by a dashed line, and pressure at the nozzle by a dashed line.

[0032] The drive waveform in this embodiment is a multi-drop drive waveform that ejects ink n times (where n is an integer of 2 or more) within one drive cycle to form one dot, and is stored, for example, in the memory of the drive circuit 12. The IC of the drive circuit 12 selects which drive waveform to input to the actuator 11 based on the grayscale data sent from the control board.

[0033] The drive waveform is a multi-drop waveform in which one pixel is composed of one or more n drops (n≧1), and comprises one or more of several output waveforms, including a first output waveform, a second output waveform with lower output efficiency than the first output waveform, a third output waveform composed of a part of the first output waveform, and a fourth output waveform composed of a part of the second output waveform. For example, the example shown in Figure 5 is a multi-drop waveform with a maximum of 3 drops. Each drive waveform comprises one or more output waveforms in succession, corresponding to the number of drops.

[0034] For example, as shown in Figure 6, the first discharge waveform W1 has a discharge waveform section Wa for discharging liquid and a cancellation waveform section Wb for suppressing residual vibration. The first discharge waveform W1 is a waveform in which the voltage is reduced from an intermediate voltage, a first voltage Vb, to a second voltage Va which is lower than the intermediate voltage, the second voltage Va is maintained for a first predetermined time, and then returned to the first voltage Vb. Then, after maintaining the first voltage Vb for a second predetermined time, a third voltage Vc which is higher than the first voltage Vb is applied for a third predetermined time, and then returned to the first voltage Vb. The intermediate voltage of the first discharge waveform is, for example, 0V and is also called the reference voltage.

[0035] For example, the width of the extended pulse of the first ejection waveform W1 is the width of AL (Acoustic Length). AL is half a period of the natural vibration period λ, which is determined by the ink characteristics and the internal structure of the print head.

[0036] As part of the ejection operation using the first ejection waveform W1, when a second voltage Va is applied as an extended pulse for a predetermined time, an electric field is generated in a predetermined direction on the piezoelectric element 115, causing the piezoelectric element 115 to deform. This deformation of the piezoelectric element 115 expands the volume of the pressure chamber 112, lowering the ink pressure inside, and the meniscus of the nozzle opening 111 is pulled significantly towards the pressure chamber 112. Then, the ink pressure in the pressure chamber 112 (ink chamber) begins to oscillate, and an oscillation in the ink flow velocity occurs with a 90-degree phase shift.

[0037] After extending the AL time with an extension pulse, returning to the first voltage Vb causes the pressure chamber 112 to return to its original shape. Then, holding the first voltage Vb for a second predetermined time causes the meniscus to advance and ink ejection to begin. After holding the first voltage Vb for the second predetermined time, applying the voltage Vc of a contraction pulse for a third predetermined time deforms the piezoelectric element 115 of the actuator 11 again, contracting the volume of the pressure chamber 112 and increasing the ink pressure, thereby suppressing fluctuations in pressure and flow velocity within the pressure chamber 112.

[0038] The second discharge waveform W2 is a waveform obtained by reducing the driving voltage of the first discharge waveform W1 to lower the discharge efficiency. Similar to the first discharge waveform W1, the second discharge waveform W2 has a discharge waveform section Wc that discharges liquid and a cancellation waveform section Wd that suppresses residual vibration. For example, the second discharge waveform W2 is a waveform obtained by reducing the driving voltage of the first discharge waveform to lower the discharge efficiency, and is configured to have a small upper and lower voltage range in the expansion pulse and contraction pulse.

[0039] As shown in Figure 7 as a specific example, in the extended pulse of the second discharge waveform W2, the voltage is reduced from the intermediate voltage, the first voltage Vb, to the fourth voltage Vd, which is lower than the intermediate voltage but higher than the second voltage. After holding the fourth voltage Vd for a predetermined time, the voltage is returned to the first voltage Vb. Then, after holding the first voltage Vb for a predetermined time, a third voltage Vc, which is higher than the first voltage Vb, is applied as the second contraction pulse for a predetermined time, and then the voltage is returned to the first voltage Vb again.

[0040] In this embodiment, the second discharge waveform W2 has an expansion pulse width that is longer than the contraction pulse width, and the duration of the intermediate voltage, the first voltage Vb, is longer than the expansion pulse width.

[0041] As shown in Figure 6, the third discharge waveform W3 is a waveform extracted from the first discharge waveform W1 and has a discharge waveform portion Wa. That is, the third discharge waveform W3 is the portion of the first discharge waveform W1 excluding the cancellation waveform portion Wb, and corresponds to the waveform for the time width before the cancellation waveform portion Wb. For example, the drive period of the third discharge waveform W3 is 2AL.

[0042] As shown in Figure 7, the fourth discharge waveform W4 is a waveform extracted from the second discharge waveform W2 and has a discharge waveform portion Wc. That is, the fourth discharge waveform W4 is the portion of the second discharge waveform W2 excluding the cancellation waveform portion Wd, and corresponds to the waveform for the time width up to the cancellation waveform portion Wd. For example, the drive period of the fourth discharge waveform is 2AL.

[0043] Figures 5 and 8 show specific examples of drive waveforms according to this embodiment. In this embodiment, when the drive circuit 12 discharges multiple drops, it discharges the first drop with the third discharge waveform W3, and the second drop with the fourth discharge waveform W4 or the second discharge waveform W2. On the other hand, when there is only one drop, it discharges it with the first discharge waveform W1.

[0044] Print data 1 is a drive waveform that ejects one drop. Print data 1 includes a first ejection waveform W1.

[0045] Print data 2 is a drive waveform that ejects two drops. The waveform of print data 2 comprises a third ejection waveform W3 that ejects the first drop and a second ejection waveform W2 that ejects the second drop.

[0046] The print data 3 is a drive waveform that ejects 3 drops. The waveform of the print data 3 comprises a third ejection waveform W3 that ejects the first drop, a fourth ejection waveform W4 that ejects the second drop, and a second ejection waveform W2 that ejects the third drop.

[0047] Figure 9 is an explanatory diagram showing the drive waveform and vibration analysis results for Comparative Example 1. The waveform for Comparative Example 1 is the first discharge waveform in Figure 5 repeated three times.

[0048] According to the liquid discharge head 10 of this embodiment, discharge performance can be improved by combining different discharge waveforms, and the circuit configuration can be simplified by extracting a portion from the base drive waveform. Specifically, four different waveforms can be generated as drive waveforms by generating circuits for the first and second discharge waveforms and extraction circuits that extract each waveform in the time direction. For example, if there are n types of second discharge waveforms, (n+1) x 2 types of waveforms can be generated. By combining multiple types of waveforms, it becomes possible to control the discharge speed from the second drop onwards more precisely.

[0049] Furthermore, according to the above embodiment, by reducing the discharge efficiency of the fourth discharge waveform W4, the increase in pressure and flow velocity during 2AL operation can be suppressed, thereby achieving stable discharge.

[0050] For example, if the third ejection waveform is repeated, the power may be too strong, potentially causing gaps in the print. However, by using waveforms with reduced ejection efficiency for the second and third drops, print quality can be ensured.

[0051] According to the above embodiment, high-speed discharge is possible during multi-drop discharge, and the drive frequency can be changed depending on the maximum number of drops. For example, as in the comparative example, if the system is driven with a first discharge waveform that does not reduce discharge efficiency, the amplification of pressure and flow velocity becomes too large, making stable discharge impossible. However, according to this embodiment, by combining multiple types of waveforms, including a second discharge waveform and a fourth discharge waveform with reduced discharge efficiency, it becomes possible to more precisely control the discharge speed from the second drop onward.

[0052] However, the embodiments of the present invention are not limited to the configurations described above.

[0053] In the above embodiment, the second discharge waveform W2 is a waveform in which the discharge efficiency is suppressed by reducing the drive voltage, but it is not limited to this. For example, as shown in Figures 10 and 11, the second discharge waveform W12 may be a waveform in which the discharge efficiency is suppressed by shortening the extension time of the first discharge waveform W1. Figure 11 is a waveform diagram of the second discharge waveform W12 in this embodiment. Figure 10 is a drive waveform diagram during 3-drop discharge, and is a drive waveform in which the third discharge waveform W3, the fourth discharge waveform W12, and the second discharge waveform W12 are applied in order. In the second discharge waveform W12, in the extension pulse, the voltage is lowered from the intermediate voltage, the first voltage Vb, to the second voltage Va which is lower than the intermediate voltage, the second voltage Va is held for a fourth predetermined time, and then returned to the first voltage Vb. The fourth predetermined time is shorter than the first predetermined time.

[0054] Even in a configuration where the discharge efficiency is reduced by the operating time, similar to the first embodiment described above, the discharge performance can be improved by combining different discharge waveforms, and the drive circuit can be simplified by extracting a portion from the base drive waveform.

[0055] For example, the above embodiment was described using a drive waveform that discharges a maximum of 3 drops, but it is not limited to this, and may also use a drive waveform that discharges 4 or more drops.

[0056] Furthermore, while an example was shown of constructing four types of discharge waveforms from two types of base drive waveforms, this is not the only option. Three or more discharge waveforms can be used as a base, and parts of them can be extracted to generate different waveforms.

[0057] As a variation, for example, when ejecting multiple drops, it is also possible to use the first ejection waveform W1 or the third ejection waveform W3. For example, if the ink viscosity is high and ejection is not possible with the second ejection waveform W2, the final drop can be ejected with the first ejection waveform W1. In other words, when ejecting three drops, it is also possible to drive by applying the third ejection waveform W3, the third ejection waveform W3, and the first ejection waveform W1 in that order, and the appropriate combination can be selected according to the viscosity and physical properties of the ink. For example, since ejection efficiency is required for the first drop, the first ejection waveform W1 or the third ejection waveform W3 can be used, and thereafter any of the first ejection waveform W1, second ejection waveform W2, third ejection waveform W3, or fourth ejection waveform W4 can be used, and in these cases as well, the drive frequency can be adjusted by the maximum number of drops. In these embodiments as well, since the multiple ejection waveforms to be selected are each divided into short units, the time can be adjusted. For example, in the case of print data that does not need to be faint, the maximum drop can be made smaller, and the printing speed can be increased accordingly.

[0058] Furthermore, the voltage values ​​applied to each piezoelectric element 115 can be adjusted as appropriate according to various conditions. For example, a potential difference may be generated by grounding one of adjacent piezoelectric elements 115 and applying a voltage to the other, or a potential difference may be generated by applying voltages to both of them separately.

[0059] For example, the configuration of the liquid discharge head 10 is not limited to the example described above, and other types of heads may be used. For example, the liquid discharge head may be configured to drive the liquid discharge section by vibrating a diaphragm provided between the pressure chamber 112 and the drive element section through deformation of the drive element section.

[0060] Furthermore, the potentials of each drive waveform can be changed as appropriate, and the voltage values ​​applied to each piezoelectric element 115 can be adjusted as appropriate according to various conditions. For example, a potential difference may be generated by grounding one of adjacent piezoelectric elements 115 and applying a voltage to the other, or a potential difference may be generated by applying voltages to both of them.

[0061] The drive waveform may be not limited to pull-driven driving, but may also be a push-driven driving or push-pull driving waveform.

[0062] For example, the configuration of the liquid ejection head 10 is not limited to the example described above, and other types of heads may be used. For example, it may be a structure that ejects ink by deforming a diaphragm with static electricity, or a heating element type structure that ejects ink from a nozzle using thermal energy such as a heater. In these cases, the diaphragm or heater acts as an actuator to apply pressure vibration inside the pressure chamber 112.

[0063] The liquid ejection device 100 is exemplified as an inkjet printer that forms a two-dimensional image using ink on an image-forming medium, but is not limited to this, and may also be a 3D printer, industrial manufacturing machine, or medical machine, for example. The liquid ejection device may be a 3D printer, industrial manufacturing machine, or medical machine, and may, for example, form a three-dimensional object by ejecting a material or a binder for solidifying the material from an inkjet head.

[0064] According to at least one embodiment described above, a drive device for a liquid discharge head that can be driven in a multi-drop manner with a simple circuit configuration can be provided.

[0065] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0066] 10...Liquid discharge head, 11...Actuator, 12...Drive circuit, 13...Data buffer, 14...Decoder, 15...Driver, 21...Liquid supply unit, 22...Transport unit, 25...Operation unit, 26...Display unit, 30...Control unit, 31...Processor, 32...ROM, 34...Image memory, 35...I / O port, 100...Liquid discharge device, 111...Nozzle, 112...Pressure chamber, 115...Piezoelectric element, 116...Electrode, 121...Waveform generation circuit, 122...First waveform extraction circuit, 123...Second waveform extraction circuit, 200...External connection device.

Claims

1. A first discharge waveform for discharging liquid, A second discharge waveform having lower discharge efficiency than the first discharge waveform, A third discharge waveform, which is composed of a part of the first discharge waveform, A drive device for a liquid discharge head, which drives an actuator that drives a pressure chamber communicating with a nozzle that discharges liquid, using a multidrop waveform comprising one or more of a plurality of discharge waveforms, including a fourth discharge waveform which is composed of a part of the second discharge waveform.

2. The first discharge waveform and the second discharge waveform each have a discharge waveform section for discharging liquid and a cancellation waveform section for suppressing residual vibration. When dispensing multiple drops, the first drop is dispensed using the third dispensing waveform, and the second drop is dispensed using the fourth or second dispensing waveform. A drive device for a liquid discharge head according to claim 1.

3. The liquid discharge head drive device according to claim 1, wherein the second discharge waveform is a waveform obtained by reducing the drive voltage of the first discharge waveform to reduce the discharge efficiency.

4. The liquid discharge head drive device according to claim 1, wherein the second discharge waveform is a waveform obtained by shortening the driving time of the first discharge waveform and reducing the discharge efficiency.

5. The drive device for a liquid discharge head according to claim 1, wherein the third discharge waveform and the fourth discharge waveform have a drive period of 2AL.

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