Liquid dispensing device

Abstract

The present invention provides a liquid dispensing device that can suppress the amount of heat generated in the voltage application circuit. [Solution] The liquid dispensing device 100 includes a main power supply 81 connected to the first electrode 53 and the second electrode 54 of the energy-giving element 46, a first sub-power supply 82 and a second sub-power supply 83 connected to the second electrode and outputting a voltage lower than the main power supply, and a plurality of drive circuit units 84 corresponding to the plurality of energy-giving elements. Each drive circuit unit includes a main switch 91 for switching the presence or absence of an electrical connection between the main power supply and the second electrode, a first sub-switch 92 provided corresponding to the first sub-power supply for switching the presence or absence of an electrical connection between the first sub-power supply and the second electrode, a second sub-switch 93 provided corresponding to the second sub-power supply for switching the presence or absence of an electrical connection between the second sub-power supply and the second electrode, and a reference switch 94 for switching the presence or absence of an electrical connection between a reference potential and the second electrode.

Description

Technical Field

[0004] , , , ,

[0005] , , , , ,

[0001] The present invention relates to a liquid ejection device.

Background Art

[0002] For example, a fluid ejection device shown in Patent Document 1 is known. This fluid ejection device has a head unit including a plurality of nozzles, a plurality of piezoelectric elements for ejecting ink droplets, and a head control circuit. The head control circuit has a function of controlling the ejection of ink droplets from the head, and by the control of the head control circuit, drive pulses of drive signals are applied to each piezoelectric element at appropriate timings.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[ID=​​​​​​To solve the above problems, a liquid discharge device according to one aspect of the present invention comprises: a plurality of energy-giving elements; a nozzle plate having a plurality of nozzles formed thereon corresponding to the plurality of energy-giving elements for discharging liquid by the plurality of energy-giving elements; and a plurality of voltage application circuits corresponding to the plurality of energy-giving elements for applying voltage to the plurality of energy-giving elements, wherein one of the plurality of energy-giving elements is a piezoelectric body in which a plurality of piezoelectric layers are stacked in a stacking direction, and comprises: a first electrode formed on a first surface extending in an orthogonal direction perpendicular to the stacking direction; a second electrode formed on a second surface that is provided at a position different from the first surface in the stacking direction and extends in the orthogonal direction; and a third electrode formed on a third surface that is provided at a position different from the first and second surfaces in the stacking direction and extends in the orthogonal direction. The voltage application circuit includes a main power supply connected to the first electrode and the second electrode, a first sub-power supply connected to the second electrode and outputting a voltage lower than the main power supply, a second sub-power supply different from the first sub-power supply and connected to the second electrode and outputting a voltage lower than the main power supply, and a plurality of drive circuit units corresponding to the plurality of energy-giving elements, each of the drive circuit units having a main switch for switching the presence or absence of an electrical connection between the main power supply and the second electrode, a first sub-switch provided corresponding to the first sub-power supply and switching the presence or absence of an electrical connection between the first sub-power supply and the second electrode, a second sub-switch provided corresponding to the second sub-power supply and switching the presence or absence of an electrical connection between the second sub-power supply and the second electrode, and a reference switch for switching the presence or absence of an electrical connection between a reference potential and the second electrode.

[0006] This configuration allows for suppression of peak current and reduces the amount of heat generated in the voltage application circuit. Therefore, ink can be ejected stably from the nozzle. [Effects of the Invention]

[0007] This invention has the effect of suppressing the amount of heat generated in a voltage application circuit. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing an example of the configuration of a liquid dispensing device. [Figure 2] Figure 1 is a cross-sectional view showing an example of the configuration of the discharge head of a liquid dispensing device. [Figure 3] Figure 1 is a circuit diagram showing an example of the configuration of the voltage application circuit of the liquid dispensing device. [Figure 4] Figure 1 is a block diagram showing an example of the functional configuration of a liquid dispensing device. [Figure 5] This figure shows the voltage and current waveforms of the second electrode of the liquid dispensing device shown in Figure 1. [Figure 6] Figure 1 is a flowchart illustrating an example of the operation of a liquid dispensing device. [Figure 7] Figure 1 is a flowchart showing the data generation process for switch control of the liquid dispensing device. [Figure 8] This figure shows another example of the voltage waveform of the second electrode of a liquid dispensing device. [Figure 9] This figure shows other examples of voltage and current waveforms of the second electrode of a liquid dispensing device. [Figure 10] This block shows another example of the functional configuration of a liquid dispensing device. [Figure 11] Figure 10 is a flowchart showing the main power control data generation process for the liquid dispensing device. [Modes for carrying out the invention]

[0009] The embodiments will be described below with reference to the drawings. However, the present invention is not limited to the embodiments described below. Furthermore, throughout the following drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions thereof are omitted.

[0010] The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, dedicated processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions, or hardware programmed to perform the enumerated functions. The hardware may be hardware disclosed herein, or other known hardware that is programmed or configured to perform the enumerated functions. If the hardware is a processor, which is considered a type of circuit, then the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or the processor.

[0011] (Embodiment 1) Figure 1 is a schematic diagram showing an example configuration of a liquid ejection device 100 according to Embodiment 1. The liquid ejection device 100 is a device that prints an image onto a recording medium 110 using liquid ejected from an ejection head 4 based on image data. In the following, an inkjet printer that ejects ink will be described as the liquid ejection device 100.

[0012] As shown in Figure 1, the liquid ejection device 100 is a serial head type inkjet printer, in which the ejection head 4 moves (scans) in the main scanning direction, ejects ink to form an image on the recording medium 110, and alternately performs the process of transporting the recording medium 110 in the sub-scanning direction.

[0013] The discharge head 4 is housed within the housing 10 of the liquid discharge device 100. Figure 2 is a cross-sectional view showing an example configuration of the discharge head 4 of the liquid discharge device 100. As shown in Figure 2, the discharge head 4 has a nozzle plate 40 on which a plurality of nozzles 41 are formed for discharging ink toward the recording medium 110 based on image data. For example, about 1200 nozzles 41 are formed on the nozzle plate 40. As shown in Figure 2, the discharge head 4 is provided with a pressure chamber 45 and an energy-giving element 46 for each nozzle 41. The pressure chamber 45 is a space that communicates with the corresponding nozzle 41. The pressure chamber 45 receives the supply of ink and temporarily stores the ink discharged from the nozzle 41. A flow path for supplying ink to the pressure chamber 45 is connected to it. The pressure chamber 45 also has an opening 47, and the energy-giving element 46 covers the opening 47.

[0014] The energy-imparting element 46 comprises a piezoelectric body 52, a first electrode 53, a second electrode 54, a third electrode 55, and a diaphragm 51. The piezoelectric body 52 is formed by stacking a plurality of piezoelectric layers 58 and 59 in the stacking direction. The diaphragm 51 is attached to the inner surface of the piezoelectric body 52. ​​Therefore, the energy-imparting element 46 is stacked in the order of piezoelectric body 52, piezoelectric layer 59, and piezoelectric layer 58 from the inside to the outside in the stacking direction. The diaphragm 51 covers the opening 47 of the pressure chamber 45. The first electrode 53 is formed on the first surface 52a located inside the piezoelectric body 52, between the piezoelectric layer 58 and the piezoelectric layer 59. The first surface 52a extends in a direction perpendicular to the stacking direction. The second electrode 54 is formed on the second surface 52b, which is the outer surface of the piezoelectric body 52. ​​The second surface 52b is located at a different position from the first surface 52a in the stacking direction and extends in a direction perpendicular to it. The third electrode 55 is formed on the inner surface of the piezoelectric body 52, on the third surface 52c located between the piezoelectric body 52 and the diaphragm 51. The third surface 52c is located at a different position from the first surface 52a and the second surface 52b in the stacking direction and extends in a perpendicular direction. The second electrode 54 is located opposite the first electrode 53 and the third electrode 55, with the piezoelectric body 52 in between. The portion of the piezoelectric layer 58 located between the first electrode 53 and the second electrode 54, along with the first electrode 53 and the second electrode 54, constitute the first active portion 56. The third electrode 55 is located at a position not opposite the first electrode 53. The portion of the piezoelectric layer 58 and piezoelectric layer 59 of the piezoelectric body 52 located between the second electrode 54 and the third electrode 55, along with the first electrode 53 and the second electrode 54, constitute the second active portion 57.

[0015] When a voltage is applied to the first active part 56 and the second active part 57 through the first electrode 53, the second electrode 54, and the third electrode 55 of the energy applying element 46, the piezoelectric body 52 elastically deform with the diaphragm 51 inside or outside the pressure chamber 45 due to the inverse piezoelectric effect. When the piezoelectric body 52 elastically deform inside the pressure chamber 45, the volume of the pressure chamber 45 decreases, and the ink inside the pressure chamber 45 is pressurized. When the voltage Vmain is applied and the ink in the pressure chamber 45 is strongly pressurized, the ink is discharged as ink droplets from the nozzle 41. Also, when the piezoelectric body 52 elastically deform outside the pressure chamber 45, the volume of the pressure chamber 45 increases, and a negative pressure is generated in the pressure chamber 45. When a strong negative pressure is generated in the pressure chamber 45, the ink flows in from the inner flow path 62 of the head. Also, the energy applying element 46 can perform non-discharge flushing that vibrates the ink inside the pressure chamber 45 and the nozzle 41 without discharging. By performing non-discharge flushing, the ink inside the pressure chamber 45 and the nozzle 41 is agitated, and it is possible to prevent a problem that makes it difficult for the ink to be discharged from the nozzle 41.

[0016] FIG. 3 is a circuit diagram showing a configuration example of a voltage application circuit 8 that applies a voltage to a plurality of energy applying elements 46. As shown in FIG. 3, the voltage application circuit 8 includes a main power supply 81, a first sub-power supply 82, a second sub-power supply 83, and a plurality of drive circuit parts 84. The main power supply 81 outputs a predetermined main power supply voltage Vmain. The first sub-power supply 82 outputs a sub-power supply voltage Vsub0 that is lower than the main power supply voltage Vmain. The second sub-power supply 83 is a sub-power supply different from the first sub-power supply 82. The second sub-power supply 83 outputs a voltage lower than the main power supply voltage Vmain of the main power supply 81. In the present embodiment, the second sub-power supply 83 outputs a sub-power supply voltage Vsub0 that is the same voltage as the first sub-power supply 82.

[0017] The plurality of drive circuit units 84 are provided corresponding to the plurality of energy application elements 46. Each drive circuit unit 84 is a sub-circuit that drives the corresponding energy application element 46. The drive circuit unit 84 applies the voltages supplied from the main power supply 81, the first sub-power supply 82, and the second sub-power supply 83 to the first active part 56 and the second active part 57 of the corresponding energy application element 46. And the drive circuit unit 84 includes a switch group 95 that switches the presence or absence of an electrical connection. The switch group 95 includes a main switch 91, a first sub-switch 92, a second sub-switch 93, and a reference switch 94. And the drive circuit unit 84 includes a wiring connecting the main power supply 81 and the first electrode 53, a wiring connecting the main power supply 81 and the second electrode 54 via the main switch 91 and a resistance element, a wiring connecting the first sub-power supply 82 and the second electrode 54 via the first sub-switch 92 and a resistance element, a wiring connecting the second sub-power supply 83 and the second electrode 54 via the second sub-switch 93 and a resistance element, a wiring connecting the reference potential GND and the second electrode 54 via the reference switch 94 and a resistance element, and a wiring connecting the third electrode 55 and the reference potential GND.

[0018] Thus, the main power supply 81 is connected to the first electrode 53 and the second electrode 54. Also, the first sub-power supply 82 and the second sub-power supply 83 are connected to the second electrode 54. And the main switch 91 is a switch that switches the presence or absence of an electrical connection between the main power supply 81 and the second electrode 54. Also, the first sub-switch 92 is provided corresponding to the first sub-power supply 82 and is a switch that switches the presence or absence of an electrical connection between the first sub-power supply 82 and the second electrode 54. Further, the second sub-switch 93 is provided corresponding to the second sub-power supply 83 and is a switch that switches the presence or absence of an electrical connection between the second sub-power supply 83 and the second electrode 54. Also, the reference switch 94 is a switch that switches the presence or absence of an electrical connection between the reference potential GND and the second electrode 54.

[0019] As a result, the potential of the first electrode 53 remains at Vmain. The potential of the third electrode 55 remains at GND. The potential of the second electrode 54 changes depending on the state of the switch group 95. In a steady state where the main switch 91 of the switch group 95 is ON and the other switches are OFF, the potential of the second electrode 54 is Vmain. In a steady state where the first sub-switch 92 of the switch group 95 is ON and the other switches are OFF, the potential of the second electrode 54 is Vsub0. Furthermore, in a steady state where the second sub-switch 93 of the switch group 95 is ON and the other switches are OFF, the potential of the second electrode 54 is Vsub0. In a steady state where the reference switch 94 of the switch group 95 is ON and the other switches are OFF, the potential of the second electrode 54 is GND.

[0020] Furthermore, the potential difference Vmain-Vsub0 between the main power supply 81 and the first sub-power supply 82 and the second sub-power supply 83 is smaller than the potential difference Vsub0 between the reference potential and the potentials of the first sub-power supply 82 and the second sub-power supply 83. In other words, Vsub0 is closer to Vmain than to GND.

[0021] The main power supply 81, the first sub-power supply 82, and the second sub-power supply 83 each include a main power supply capacitor 81a, a first sub-power supply capacitor 82a, and a second sub-power supply capacitor 83a, respectively. The main power supply capacitor 81a, the first sub-power supply capacitor 82a, and the second sub-power supply capacitor 83a are each connected in parallel to their respective power supplies, allowing for charging and discharging of their charge.

[0022] Furthermore, as shown in Figure 1, the ejection head 4 is provided with an ink supply port 43 into which ink supplied from the outside flows. The internal flow path 62 of the head connects the ink supply port 43 and the pressure chamber 45.

[0023] The liquid dispensing device 100 is equipped with a platen 11 positioned opposite the dispensing head 4. The platen 11 is located at a predetermined distance below the dispensing head 4 and has a flat upper surface. The upper surface of the platen 11 supports the recording medium 110 from below.

[0024] Furthermore, the liquid dispensing device 100 includes a transport unit 12 that transports the recording medium 110 on the platen 11 in the sub-scanning direction. The transport unit 12 has, for example, two transport rollers 13 and a transport motor. The two transport rollers 13 extend in the main scanning direction and, when viewed from a direction perpendicular to the main scanning direction and the sub-scanning direction, are positioned apart in the sub-scanning direction with the platen 11 in between. Each transport roller 13 is connected to the rotation axis of the transport motor via a reduction gear. Therefore, when the transport motor is driven, the two transport rollers 13 rotate around their axes and transport the recording medium 110 on the platen 11 in the sub-scanning direction.

[0025] Furthermore, the liquid dispensing device 100 includes a moving mechanism 2 that moves the dispensing head 4 and the recording medium 110 relative to each other. In this embodiment, the moving mechanism 2 is a mechanism that moves the dispensing head 4, and is a mechanism that moves the dispensing head 4 back and forth in the main scanning direction within a predetermined reciprocating movement range.

[0026] The moving mechanism 2 includes a carriage 21 that supports the discharge head 4 and reciprocates with the discharge head 4 in the main scanning direction, and a carriage drive unit 22 that drives the carriage 21. The carriage drive unit 22 includes two guide rails 26, an endless belt 27, two pulleys 28, and a moving motor 29. The two guide rails 26, when viewed from a third direction, extend in the main scanning direction so as to cross the platen 11 and are spaced apart in the sub-scanning direction. The two guide rails 26 support the carriage 21 and guide the carriage 21 in the main scanning direction.

[0027] Two pulleys 28 are provided near both ends of one of the guide rails 26. An endless belt 27 is wrapped around the two pulleys 28. A carriage 21 is connected to a predetermined point on the endless belt 27. One of the pulleys 28 is also connected to the rotating shaft of the moving motor 29 via a reduction gear. Therefore, when the moving motor 29 is driven, the endless belt 27 moves in a circular motion, and the carriage 21 supporting the discharge head 4 moves along the guide rail 26 in the main scanning direction.

[0028] The liquid ejection device 100 includes a tank 3 that contains ink to be supplied to the ejection head 4. The tank 3 is, for example, a cartridge-type tank and is held in a predetermined position within the housing 10. The tank 3 is covered by an openable and closable cover provided on the housing 10. The tank 3 can be attached to or removed from the liquid ejection device 100 by opening the cover.

[0029] The liquid dispensing device 100 includes a conduit 61 that connects the tank 3 and the ink supply port 43, and supplies the ink stored in the tank 3 to the ink supply port 43 of the dispensing head 4. The conduit 61 is, for example, a flexible resin tube, and when the distance between the carriage 21 and the tank 3 changes due to the movement of the carriage 21, the conduit 61 bends and deforms, maintaining the connection between the tank 3 and the dispensing head 4. The supply channel 5, which is formed by the conduit 61 and the internal channel 62 of the head, forms a channel that supplies liquid to the pressure chamber 45.

[0030] Figure 4 is a block diagram showing an example of the functional configuration of the liquid dispensing device 100. As shown in Figure 4, the liquid dispensing device 100 includes a controller 7. The controller 7 has a functional configuration mainly consisting of hardware, including a control unit 71, a storage unit 72 connected to the control unit 71, and an interface 73. The control unit 71 is also connected to the switch group 95 of the voltage application circuit 8, the transport unit 12, and the moving mechanism 2.

[0031] The control unit 71 is, for example, a computer and includes circuits such as a processor like an MPU or an integrated circuit like an ASIC. The storage unit 72 is a memory accessible from the control unit 71 and includes, for example, RAM and ROM. Of these, the RAM temporarily stores image data and various data during calculations performed by the control unit 71. The ROM stores computer programs and data for various data processing. Therefore, the control unit 71 controls the operation of each part of the liquid dispensing device 100 by executing computer programs while referring to the data stored in the storage unit 72.

[0032] Interface 73 is a connection device that connects the control unit 71 to external devices of the liquid dispensing device 100. Examples of external devices include other computers, communication networks, recording media, displays, and other liquid dispensing devices. The liquid dispensing device 100 acquires image data and print setting information from external devices, such as computers, via this interface 73. This image data includes raster data representing an image to be printed on the recording media 110, which has RGB value gradation information.

[0033] The moving mechanism 2 has a moving drive circuit electrically connected to the moving motor 29 described above, and the operation of the moving motor 29 is controlled by the control unit 71 via the moving drive circuit. As a result, the moving mechanism 2 can move the carriage 21 supporting the discharge head 4 in the main scanning direction at any speed, and can also stop the carriage 21 at any position within its range of motion. Therefore, the discharge head 4 mounted on the carriage 21 is moved back and forth in the main scanning direction relative to the recording medium 110 by the moving mechanism 2.

[0034] The control unit 71 then outputs a control signal that controls the on / off state of the switch group 95, thereby switching the main switch 91, the first sub-switch 92, the second sub-switch 93, and the reference switch 94 on or off. This generates a voltage waveform that drives the energy-generating element 46, which controls the first active unit 56 and the second active unit 57, and changes the volume of the pressure chamber 45.

[0035] The transport unit 12 has a transport drive circuit electrically connected to the transport motor described above, and the operation of the transport motor is controlled by the control unit 71 via the transport drive circuit. As a result, the transport unit 12 can transport the recording medium 110 on the platen 11 intermittently or continuously in the forward and backward direction, and can also stop and hold it at a predetermined position on the platen 11.

[0036] The controller 7 moves the carriage 21 in the main scanning direction using the moving mechanism 2 and performs a pass printing process by ejecting ink from the nozzle 41 according to a control signal, thereby forming an image on the recording medium 110 in one pass at a time. Specifically, the liquid ejection device 100 transports the recording medium 110 using the transport unit 12 and stops it at a predetermined position on the platen 11, and then moves the ejection head 4 in one direction in the main scanning direction using the moving mechanism 2, ejecting ink from the nozzle 41 in the printing area P and landing it on the recording medium 110. In this way, a partial image of one pass is formed on the stopped recording medium 110 by the ink ejected as the ejection head 4 moves.

[0037] Then, once a partial image for one pass is formed, the transport unit 12 transports the recording medium 110 by a predetermined distance while the ejection head 4 is in standby mode. Once the transport of the recording medium 110 is complete, the movement mechanism 2 moves the ejection head 4 to the other side in the main scanning direction, ejecting ink from the nozzle 41 to form the next partial image for one pass. The liquid ejection device 100 prints an overall image consisting of one or more partial images onto the recording medium 110 by alternately repeating the transport of the recording medium 110 and the ejection of ink. The controller 7 also performs non-ejection flushing to agitate the ink inside the pressure chamber 45 and the nozzle 41.

[0038] In addition to the above, the liquid dispensing device 100 may also be equipped with other functional hardware components, such as output devices that output various types of information to the outside, such as a display and a speaker, and input devices that accept input of information from the outside, such as a touch panel and a physical switch.

[0039] [Example of operation of the drive circuit section] Next, we will specifically describe an example of the operation of one drive circuit 84 corresponding to one energy-giving element 46, among the multiple drive circuit sections 84 included in the voltage application circuit 8 during one drive cycle. Figure 5 shows the voltage waveform and current waveform of the second electrode 54. The drive cycle is, for example, 42 μs, but is not limited to this.

[0040] The following describes an example of the operation of the drive circuit 84 that generates the voltage waveform shown in Figure 5. The voltage waveform shown in Figure 5 is an example of an ejection waveform that ejects ink from the nozzle 41. The voltage waveform is not limited to the waveform shown in Figure 5. Various voltage waveforms can be generated by changing the control timing of the switch group 95 and the voltage supplied from the power supply. For example, as ejection waveforms, waveforms for ejecting large droplets, medium droplets, and small droplets may be generated. In addition, a voltage waveform that performs non-ejection flushing may be generated. Furthermore, although the voltage waveform shown in Figure 5 is a pulse waveform, it is not limited to this.

[0041] First, in the initial state, the main switch 91, the first sub-switch 92, and the second sub-switch 93 are ON, and the reference switch 94 is ON. In this initial state, the potential of the second electrode 54 is the reference potential GND. As described above, the potential of the first electrode 53 is Vmain, and the potential of the third electrode 55 is GND. Therefore, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, is Vmain, and the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, is 0.

[0042] Next, at time t1, the reference switch 94 is turned off and the first sub-switch 92 is turned on. As a result, current flows from the first sub-power supply 82 to the energy supply element 46. The potential of the second electrode 54 rises to the potential Vsub0 of the first sub-power supply 82. Therefore, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, decreases from Vmain to Vmain-Vsub0. Also, the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, rises from 0 to Vsub0.

[0043] Next, at time t2, the first sub-switch 92 is turned off and the main switch 91 is turned on. As a result, current flows from the main power supply 81 to the energy supply element 46. The potential of the second electrode 54 rises to the potential Vmain of the main power supply 81. Therefore, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, further decreases from Vmain-Vsub0 to 0. Also, the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, rises from Vsub0 to Vmain.

[0044] Next, at time t3, the main switch 91 is turned off, and one or more of the first sub-switch 92 and the second sub-switch 93 are turned on. As a result, charge is discharged from the piezoelectric element 52, and the charge is recovered into one or more of the first sub-power supply 82 and the second sub-power supply 83. The recovered charge is stored in the sub-power supply capacitors 82a and 83a. The potential of the second electrode 54 then decreases to the potential Vsub0 of the first sub-power supply 82 and the second sub-power supply 83. Therefore, the charging voltage of the first active section 56, which is the potential difference between the first electrode 53 and the second electrode 54, rises from 0 to Vmain-Vsub0. Also, the charging voltage of the second active section 57, which is the potential difference between the second electrode 54 and the third electrode 55, decreases from Vmain to Vsub0. In this way, when the energy-giving element 46 is charged by applying a voltage to the second electrode 54 with the main power supply 81 and then discharged, the charge from the second electrode 54 is regenerated to the first sub-power supply 82, thus reusing energy and reducing power consumption.

[0045] Next, at time t4, the ON switch of the first sub-switch 92 and the second sub-switch 93 is turned OFF, and the reference switch 94 is turned ON. As a result, current flows from the piezoelectric element 52 to GND, causing it to discharge. The potential of the second electrode 54 then drops to the reference potential GND. Consequently, the charging voltage of the first active section 56, which is the potential difference between the first electrode 53 and the second electrode 54, rises further from Vmain-Vsub0 to Vmain. Also, the charging voltage of the second active section 57, which is the potential difference between the second electrode 54 and the third electrode 55, drops further from Vsub0 to 0. In this way, the switching of the switch group 95 applies the voltage waveform shown in Figure 5 to the second electrode 54, causing the piezoelectric element 52 to vibrate.

[0046] Note that the energy-transferring element 46 operates similarly even if the second sub-switch 93 is switched instead of the first sub-switch 92. By switching the second sub-switch 93 instead of the first sub-switch 92, the second sub-power supply 83 applies voltage to the second electrode 54 instead of the first sub-power supply 82.

[0047] [Example of liquid dispensing device operation] Next, we will specifically describe an example of the operation of the liquid ejection device 100 in the printing process. Figure 6 is a flowchart showing an example of the operation of the liquid ejection device 100.

[0048] First, the control unit 71 acquires print data, including image data and print setting information, from an external device, such as a computer, via the interface 73 (step S1).

[0049] Next, the control unit 71 generates control data for the switch group 95, the transport unit 12, and the moving mechanism 2 based on the print data (step S2). When generating the control data for the switch group 95, the control unit 71 generates switch control data, which is control data for each drive cycle. Figure 7 is a flowchart of the switch control data generation process. This will be described in detail below.

[0050] First, the control unit 71 identifies the nozzle 41 that ejects ink during the target drive cycle based on the print data (step S21). Here, identifying the nozzle 41 is equivalent to identifying the energy-generating element 46 corresponding to the identified nozzle 41 as the element to be controlled. Specifically, the element to be controlled is identified by storing the nozzle number in a volatile memory.

[0051] Next, the control unit 71 determines whether the number of controlled elements, which are energy-generating elements 46 corresponding to the ink-discharging nozzles 41, is less than a predetermined threshold (step S22).

[0052] Then, when the control unit 71 determines that the number of controlled elements is less than a predetermined threshold during the drive cycle of the processing target (YES in step S22), it sets control data to apply a voltage from the first sub-power supply 82 or the second sub-power supply 83 when raising the potential of the second electrode 54 to Vsub0 at time t1 (step S23). In this embodiment, when the control unit 71 raises the potential of the second electrode 54 to Vsub0 at time t1, it sets control data to turn on the first sub-switch 92 of the drive circuit unit 84 corresponding to the controlled element and apply a voltage from the first sub-power supply 82 to the controlled element.

[0053] Furthermore, the control unit 71 sets control data to regenerate the charge discharged from the energy supply element 46 to the first sub-power supply 82 or the second sub-power supply 83 when the potential of the second electrode 54 is reduced from Vmain to Vsub0 at time t3 (step S24). In this embodiment, at time t3, the control unit 71 turns on the first sub-switch 92 and sets control data to regenerate the charge discharged from the energy supply element 46 to the first sub-power supply 82.

[0054] On the other hand, if the control unit 71 determines that the number of controlled elements is greater than or equal to a predetermined threshold during the drive cycle of the processing target (NO in step S22), it divides the controlled elements into two groups corresponding to the first sub-power supply 82 and the second sub-power supply 83 (step S25).

[0055] Next, the control unit 71 sets control data to apply voltage from the first sub-power supply 82 and the second sub-power supply 83 when raising the potential of the second electrode 54 from GND to Vsub0 at time t1 (step S26). Specifically, the control unit 71 sets control data to apply voltage from the first sub-power supply 82 to the controlled elements belonging to one group by turning on the first sub-switch 92 and keeping the second sub-switch 93 off. The control unit 71 also sets control data to apply voltage from the second sub-power supply 83 to the controlled elements belonging to the other group by turning on the second sub-switch 93 and keeping the first sub-switch 92 off.

[0056] Next, the control unit 71 sets control data to regenerate the charge discharged from the energy supply element 46 to the first sub-power supply 82 or the second sub-power supply 83 when the potential of the second electrode 54 is reduced from Vmain to Vsub0 at time t3 (step S27). In this embodiment, at time t3, the control unit 71 turns on both the first sub-switch 92 and the second sub-switch 93 to regenerate the charge discharged from the energy supply element 46 to both the first sub-power supply 82 and the second sub-power supply 83.

[0057] Next, the control unit 71 controls the switch group 95, the transport unit 12, and the moving mechanism 2 based on the control data including the switch control data to execute the printing process (step S3).

[0058] In this way, when the control unit 71 raises the potential of the second electrode 54 from GND to Vmain in order to eject ink from the nozzle 41, it first raises the potential of the second electrode 54 from GND to the potential Vsub0 between GND and Vmain using the first sub-power supply 82 or the second sub-power supply 83, and then raises it from Vsub0 to Vmain using the main power supply 81. This suppresses the peak current flowing through the voltage application circuit 8 when the control unit 71 raises the potential of the second electrode 54 from GND to Vmain, and thus suppresses the amount of heat generated in the voltage application circuit 8. As a result, ink can be ejected stably from the nozzle 41.

[0059] Furthermore, when the number of controlled elements to which voltage is applied in the same drive cycle exceeds a predetermined threshold, the control unit 71 distributes the power supply to the energy-giving element 46 between the first sub-power supply 82 and the second sub-power supply 83 when raising the potential of the second electrode 54 from GND to Vsub0. This suppresses the peak current of each sub-power supply and further reduces the amount of heat generated by the voltage application circuit 8.

[0060] Furthermore, when the number of controlled elements to which voltage is applied in the same drive cycle is less than a predetermined threshold, the control unit 71 applies voltage to the second electrodes 54 of the multiple energy-giving elements 46 using the main power supply 81 at time t2 to charge the multiple energy-giving elements 46, and then regenerates the energy to the first sub-power supply 82 or the second sub-power supply 83 when discharging the multiple energy-giving elements 46 at time t3. More specifically, when the number of controlled elements to which voltage is applied in the same drive cycle is less than a predetermined threshold, the control unit 71 switches from a first state in which the main switch 91 is ON, the first sub-switch 92 is OFF, the second sub-switch 93 is OFF, and the reference switch 94 is OFF, to a second state in which the main switch 91 is OFF, the first sub-switch 92 is ON, the second sub-switch 93 is OFF, and the reference switch 94 is OFF, or switches from the first state to a third state in which the main switch 91 is OFF, the first sub-switch 92 is OFF, the second sub-switch 93 is ON, and the reference switch 94 is OFF. On the other hand, when the amount of charge discharged from multiple energy-generating elements 46 exceeds a predetermined threshold, the charge is regenerated to the first sub-power supply 82 and the second sub-power supply 83. More specifically, when the number of controlled elements to which voltage is applied in the same drive cycle exceeds a predetermined threshold, the control unit switches from the first state to a fourth state in which the main switch 91 is off, the first sub-switch 92 is on, the second sub-switch 93 is on, and the reference switch 94 is off. In this way, the control unit 71 switches between a state in which the charge is regenerated to the first sub-power supply 82 or the second sub-power supply 83, and a state in which the charge is regenerated to both the first sub-power supply 82 and the second sub-power supply 83, depending on the number of controlled elements. Therefore, the charge discharged from the energy-generating elements 46 can be distributed to the first sub-power supply 82 and the second sub-power supply 83. This makes it possible to suppress the capacitance of the sub-power supply capacitors 82a and 83a. It also makes it possible to suppress the voltage rise.

[0061] Furthermore, the potential difference Vmain-Vsub0 between the main power supply 81 and the first sub-power supply 82 is smaller than the potential difference Vsub0 between the reference potential and the potential of the first sub-power supply 82. Therefore, when raising the potential of the second electrode 54 from GND to Vmain, the potential difference Vmain-Vsub0 handled by the main power supply 81 can be reduced. Note that by reducing the potential difference Vmain-Vsub0 handled by the main power supply 81, the potential difference Vsub0 handled by the sub-power supply increases, but the portion handled by the sub-power supply is further shared by multiple sub-power supplies. Therefore, the peak current of the voltage application circuit 8 as a whole can be suppressed, and the amount of heat generated by the voltage application circuit 8 can be suppressed. In addition, when lowering the potential of the second electrode 54 from Vmain to Vsub0, the charge discharged from the energy-giving element 46 can be suppressed, and the capacitance of the sub-power supply capacitors 82a and 83a can be suppressed. Furthermore, the voltage rise can be suppressed.

[0062] (Embodiment 2) In the above embodiment 1, the control unit 71 switches between a state in which power is regenerated to the first sub-power supply 82 or the second sub-power supply 83, and a state in which power is regenerated to both the first sub-power supply 82 and the second sub-power supply 83, depending on the number of elements to be controlled.

[0063] In this embodiment, the control unit 71 switches between a state in which the charge discharged from the energy-giving elements 46 is regenerated to the first sub-power supply 82 or the second sub-power supply 83, and a state in which the charge is regenerated to both the first sub-power supply 82 and the second sub-power supply 83, depending on the potential difference before and after the discharge of the multiple energy-giving elements 46. More specifically, when the charge discharged from the energy-giving elements 46 is regenerated to the first sub-power supply 82 or the second sub-power supply 83, the control unit 71 switches from a first state in which the main switch 91 is ON, the first sub-switch 92 is OFF, the second sub-switch 93 is OFF, and the reference switch 94 is OFF, to a second state in which the main switch 91 is OFF, the first sub-switch 92 is ON, the second sub-switch 93 is OFF, and the reference switch 94 is OFF, or switches from the first state to a third state in which the main switch 91 is OFF, the first sub-switch 92 is OFF, the second sub-switch 93 is ON, and the reference switch 94 is OFF. On the other hand, when the charge discharged from the energy supply element 46 is regenerated to the first sub-power supply 82 and the second sub-power supply 83, the control unit 71 switches from the first state to a fourth state in which the main switch 91 is off, the first sub-switch 92 is on, the second sub-switch 93 is on, and the reference switch 94 is off.

[0064] This allows the charge discharged from the energy-giving elements 46 to be distributed to the first sub-power supply 82 and the second sub-power supply 83 when the potential difference before and after discharge of the multiple energy-giving elements 46 is large and the charge discharged from the energy-giving elements 46 is large. Therefore, the capacitance of the sub-power supply capacitors 82a and 83a can be suppressed. In addition, the voltage rise can be suppressed.

[0065] (Embodiment 3) The following describes the configuration and operation of Embodiment 3, focusing on the differences from Embodiment 1.

[0066] In this embodiment, the first sub-power supply 82 outputs a voltage Vsub1 (first voltage), and the second sub-power supply 83 outputs a voltage Vsub2 (second voltage) that is higher than the voltage Vsub1.

[0067] [Example of operation of the drive circuit section] Next, we will specifically describe an example of the operation of one drive circuit 84 corresponding to one energy-imparting element 46 among the multiple drive circuit 84 included in the voltage application circuit 8 during one drive cycle. Figure 8 shows the voltage waveform of the second electrode 54 in this embodiment.

[0068] The operation of the drive circuit 84 that generates the voltage waveform shown in Figure 8 will be explained below. The voltage waveform in Figure 8 is the voltage waveform that performs non-discharge flushing.

[0069] First, in the initial state, the main switch 91, the first sub-switch 92, and the second sub-switch 93 are ON, and the reference switch 94 is ON. Therefore, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, is Vmain, and the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, is 0.

[0070] Next, at time t1, the reference switch 94 is turned off and the first sub-switch 92 is turned on. As a result, current flows from the first sub-power supply 82 to the energy supply element 46. The potential of the second electrode 54 rises to the potential Vsub1 of the first sub-power supply 82. Therefore, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, decreases from Vmain to Vmain-Vsub1. Also, the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, rises from 0 to Vsub1.

[0071] Next, at time t2, the first sub-switch 92 is turned off and the reference switch 94 is turned on. As a result, current flows from the piezoelectric element 52 to GND and discharges. The potential of the second electrode 54 then drops to the reference potential GND. Consequently, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, rises from Vmain-Vsub1 to Vmain. Also, the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, drops from Vsub1 to 0.

[0072] Next, at time t3, the reference switch 94 is turned off and the second sub-switch 93 is turned on. As a result, current flows from the second sub-power supply 83 to the energy supply element 46. The potential of the second electrode 54 rises to the potential Vsub2 of the second sub-power supply 83. Therefore, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, decreases from Vmain to Vmain-Vsub2. Also, the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, rises from 0 to Vsub2.

[0073] Next, at time t4, the second sub-switch 93 is turned off and the reference switch 94 is turned on. As a result, current flows from the piezoelectric element 52 to GND and discharges. The potential of the second electrode 54 then drops to the reference potential GND. Consequently, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, rises from Vmain-Vsub2 to Vmain. Also, the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, drops from Vsub2 to 0.

[0074] In this embodiment, the control unit 71 applies a voltage to the second electrode 54 using the first sub-power supply 82 and the second sub-power supply 83 within the drive cycle. Then, by switching the switch group 95, the voltage waveform shown in Figure 8 is applied to the second electrode 54, causing the piezoelectric element 52 to vibrate.

[0075] (Embodiment 4) The configuration and operation of Embodiment 4 are described below, focusing on the differences from Embodiment 1.

[0076] In this embodiment, the first sub-power supply 82 outputs a voltage Vsub1 (first voltage), and the second sub-power supply 83 outputs a voltage Vsub2 (second voltage) that is higher than the voltage Vsub1.

[0077] [Example of operation of the drive circuit section] Next, we will specifically describe an example of the operation of one drive circuit 84 corresponding to one energy-giving element 46 among the multiple drive circuit 84 included in the voltage application circuit 8 during one drive cycle. Figure 9 is a graph showing the voltage waveform of the second electrode 54 in this embodiment.

[0078] The operation of the drive circuit 84 that generates the voltage waveform shown in Figure 9 will be explained below.

[0079] First, in the initial state, the main switch 91, the first sub-switch 92, and the second sub-switch 93 are ON, and the reference switch 94 is ON. Therefore, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, is Vmain, and the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, is 0.

[0080] Next, at time t1, the reference switch 94 is turned off and the first sub-switch 92 is turned on. As a result, current flows from the first sub-power supply 82 to the energy supply element 46. The potential of the second electrode 54 rises to the potential Vsub1 of the first sub-power supply 82. Therefore, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, decreases from Vmain to Vmain-Vsub1. Also, the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, rises from 0 to Vsub1.

[0081] Next, at time t2, the first sub-switch 92 is turned off and the second sub-switch 93 is turned on. As a result, current flows from the second sub-power supply 83 to the energy supply element 46. The potential of the second electrode 54 rises to the potential Vsub2 of the second sub-power supply 83. Therefore, the charging voltage of the first active unit 56, which is the potential difference between the first electrode 53 and the second electrode 54, further decreases from Vmain-Vsub1 to Vmain-Vsub2. Also, the charging voltage of the second active unit 57, which is the potential difference between the second electrode 54 and the third electrode 55, rises from Vsub1 to Vsub2.

[0082] Next, at time t3, the second sub-switch 93 is turned off and the main switch 91 is turned on. As a result, current flows from the main power supply 81 to the energy supply element 46. The potential of the second electrode 54 rises to the potential Vmain of the main power supply 81. Therefore, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, further decreases from Vmain-Vsub2 to 0. Also, the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, rises from Vsub2 to Vmain.

[0083] Next, at time t4, the main switch 91 is turned off and the second sub-switch 93 is turned on. As a result, charge is discharged from the energy-giving element 46 and current is regenerated into the second sub-power supply 83. The potential of the second electrode 54 then drops to the potential Vsub2 of the second sub-power supply 83. Consequently, the charging voltage of the first active unit 56, which is the potential difference between the first electrode 53 and the second electrode 54, rises from 0 to Vmain-Vsub2. Also, the charging voltage of the second active unit 57, which is the potential difference between the second electrode 54 and the third electrode 55, drops from Vmain to Vsub2.

[0084] Next, at time t5, the second sub-switch 93 is turned off and the first sub-switch 92 is turned on. As a result, charge is discharged from the energy-giving element 46 and current is regenerated into the first sub-power supply 82. The potential of the second electrode 54 then drops to the potential Vsub1 of the first sub-power supply 82. Consequently, the charging voltage of the first active unit 56, which is the potential difference between the first electrode 53 and the second electrode 54, rises further from Vmain-Vsub2 to Vmain-Vsub1. Also, the charging voltage of the second active unit 57, which is the potential difference between the second electrode 54 and the third electrode 55, drops further from Vsub2 to Vsub1.

[0085] Next, at time t6, the first sub-switch 92 is turned off and the reference switch 94 is turned on. As a result, current flows from the piezoelectric element 52 to GND and discharges. The potential of the second electrode 54 then drops to the reference potential GND. Consequently, the charging voltage of the first active part 56, which is the potential difference between the first electrode 53 and the second electrode 54, rises further from Vmain-Vsub1 to Vmain. Also, the charging voltage of the second active part 57, which is the potential difference between the second electrode 54 and the third electrode 55, drops further from Vsub1 to 0.

[0086] Thus, in this embodiment, the control unit 71 applies a voltage from the first sub-power supply 82 to the same second electrode 54, and then applies a voltage from the second sub-power supply 83 with a different output voltage to generate a single voltage waveform that drives the energy-giving element 46. Then, by switching the switch group 95, the voltage waveform shown in Figure 9 is applied to the second electrode 54, causing the piezoelectric element 52 to vibrate.

[0087] (Embodiment 5) The configuration and operation of Embodiment 5 will be described below, focusing on the differences from Embodiment 1. Figure 10 is a block diagram showing an example of the functional configuration of the liquid dispensing device in this embodiment.

[0088] As shown in Figure 10, in this embodiment, the main power supply 81 includes an output switching unit 86. The output switching unit 86 performs the function of switching the output voltage of the main power supply 81 between Vmain1 and Vmain2, which is higher than Vmain1. The output switching unit 86 is connected to the control unit 71. Vmain1 is, for example, 40V, and Vmain2 is, for example, 42V.

[0089] [Example of liquid dispensing device operation] In step S2 of Embodiment 1, the control unit 71 generates control data for the switch group 95, the transport unit 12, and the moving mechanism 2 based on the print data. In this embodiment, the control unit 71 further generates main power supply control data generation processing, which is control data for the output voltage of the main power supply 81 for each drive cycle.

[0090] Figure 11 is a flowchart showing the main power control data generation process for each drive cycle of the main power supply 81.

[0091] First, the control unit 71 identifies the nozzle 41 that ejects ink during the target drive cycle based on the print data (step S31).

[0092] Next, the control unit 71 determines whether the number of controlled elements, which are energy-generating elements 46 corresponding to the ink-discharging nozzles 41, is less than a predetermined threshold (step S32).

[0093] Then, when the control unit 71 determines that the number of elements to be controlled is less than a predetermined threshold (YES in step S32), it sets the output voltage of the main power supply 81 to Vmain1 during the drive cycle of the element to be processed (step S33).

[0094] On the other hand, if the control unit 71 determines that the number of controlled elements to which voltage is applied in the same drive cycle is greater than or equal to a predetermined threshold (NO in step S32), it sets the output voltage of the main power supply 81 to Vmain2 in the drive cycle to be processed (step S34).

[0095] Next, the control unit 71 controls the switch group 95, the transport unit 12, the moving mechanism 2, and the output switching unit 86 based on the control data including the switch control data to execute the printing process (step S3).

[0096] Thus, in this embodiment, as the number of controlled elements, which are energy-giving elements 46 corresponding to nozzles 41 that eject ink in the same drive cycle, increases, the output switching unit 86 switches the output of the main power supply 81 to a higher voltage. This prevents the voltage applied to each energy-giving element 46 from decreasing and causing the ink ejection operation to become unstable when a voltage is applied to a large number of energy-giving elements 46.

[0097] (Embodiment 6) In embodiments 1 to 6 described above, the voltage application circuit 8 is exemplified as having two power sources, a first sub-power source 82 and a second sub-power source 83, as sub-power sources. However, it is not limited to this configuration and may have three or more power sources. In this case, the drive circuit section 84 of the voltage application circuit 8 is provided with sub-switches corresponding to each sub-power source.

[0098] From the above description, many improvements and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the above description should be interpreted as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of its structure and / or function can be substantially modified without departing from the spirit of the invention. [Explanation of symbols]

[0099] 8. Voltage application circuit 40 Nozzle Plates 41 nozzles 45 Pressure Chamber 46 Energy-giving elements 52a 1st page 52b Page 2 52c 3rd page 53 1st electrode 54 2nd electrode 55 3rd electrode 56 1st active part 57 2nd active part 71 Control Unit 81 Main Power Supply 82. First Sub-Power Supply 83 Second Sub-Power Supply 84 Drive Circuit Section 91 Main Switch 92 First Subswitch 93 Second Subswitch 94 Reference Switch 100 Liquid dispensing device

Claims

1. Multiple energy-contributing elements, A nozzle plate having a plurality of nozzles formed on it, corresponding to the plurality of energy-giving elements, for discharging liquid by the plurality of energy-giving elements, The system includes a voltage application circuit that applies a voltage to the plurality of energy-generating elements, One of the multiple energy-giving elements is a piezoelectric body in which multiple piezoelectric layers are stacked in a stacking direction, and comprises a first electrode formed on a first surface extending in a direction perpendicular to the stacking direction, a second electrode formed on a second surface provided at a position different from the first surface in the stacking direction and extending in the direction perpendicular to the stacking direction, and a third electrode formed on a third surface provided at a position different from the first and second surfaces in the stacking direction and extending in the direction perpendicular to the stacking direction. The voltage application circuit is A main power supply connected to the first electrode and the second electrode, A first sub-power supply connected to the second electrode and outputting a voltage lower than the main power supply, A second sub-power supply, which is different from the first sub-power supply, is connected to the second electrode and outputs a voltage lower than that of the main power supply, It has a plurality of drive circuit sections corresponding to the plurality of energy-generating elements, Each of the aforementioned drive circuit sections is: A main switch that switches the presence or absence of an electrical connection between the main power supply and the second electrode, A first sub-switch is provided corresponding to the first sub-power supply and switches the presence or absence of an electrical connection between the first sub-power supply and the second electrode, A second sub-switch is provided corresponding to the second sub-power supply and switches the presence or absence of an electrical connection between the second sub-power supply and the second electrode, A liquid dispensing device having a reference switch that switches between a reference potential and the presence or absence of an electrical connection between the second electrode and the reference potential.

2. Equipped with a control unit, The control unit, Obtain print data, Based on the print data, a voltage is applied to the second electrode of the controlled element, which is the energy-giving element corresponding to the nozzle that discharges the liquid in the same drive cycle, using the main power supply and a predetermined number of sub-power supplies. The liquid dispensing device according to claim 1, wherein when the number of controlled elements is less than a predetermined threshold, a voltage is applied from the first sub-power supply or the second sub-power supply to the second electrode, and when the number of controlled elements is equal to or greater than the threshold, a voltage is applied from the first sub-power supply and the second sub-power supply to the second electrode.

3. It includes a control unit, The control unit, The liquid dispensing device according to claim 1, wherein a voltage is applied to the second electrode using the first sub-power supply and the second sub-power supply within the drive cycle.

4. It includes a control unit, The first sub-power supply outputs a first voltage, The second sub-power supply outputs a second voltage that is higher than the first voltage. The control unit, A voltage waveform is generated to drive the energy-generating element by applying a voltage from the first sub-power supply to the same second electrode, followed by applying a voltage from the second sub-power supply. The liquid dispensing device according to claim 1.

5. The output switching unit switches the output voltage of the main power supply, It comprises a control unit and, The control unit, Obtain print data, The liquid dispensing device according to claim 1, wherein, based on the print data, as the number of controlled elements which are energy-generating elements corresponding to the nozzles that dispense the liquid in the same drive cycle increases, the output switching unit switches the output of the main power supply to a higher voltage.

6. It includes a control unit, The control unit, The liquid dispensing device according to claim 1, wherein when a voltage is applied to the second electrode by the main power supply to charge the energy-giving element, and the energy-giving element is discharged, the charge from the second electrode is regenerated to the first sub-power supply, the second sub-power supply, or either the first sub-power supply or the second sub-power supply.

7. The control unit, Switching the main switch, the first sub-switch, the second sub-switch, and the reference switch on or off, The liquid dispensing device according to claim 6, wherein when regenerating the charge from the second electrode to the first sub-power supply or the second sub-power supply, the device switches from a first state in which the main switch is ON, the first sub-switch is OFF, the second sub-switch is OFF, and the reference switch is OFF, to a second state in which the main switch is OFF, the first sub-switch is ON, the second sub-switch is OFF, and the reference switch is OFF, or to a third state in which the main switch is OFF, the first sub-switch is OFF, the second sub-switch is ON, and the reference switch is OFF.

8. The control unit, The liquid dispensing device according to claim 6, wherein, after charging the plurality of energy-giving elements by applying a voltage to the second electrodes of the plurality of energy-giving elements with the main power supply, the plurality of energy-giving elements are discharged, and the power is regenerated to the first sub-power supply, the second sub-power supply, or either the first sub-power supply or the second sub-power supply, according to the potential difference before and after the discharge of the plurality of energy-giving elements.

9. The control unit, Switching the main switch, the first sub-switch, the second sub-switch, and the reference switch on or off, The liquid dispensing device according to claim 8, wherein when the charge from the second electrode is regenerated to the first sub-power supply or the second sub-power supply, the main switch is turned on, the first sub-switch is turned off, the second sub-switch is turned off, and the reference switch is turned off, switches from a first state in which the main switch is turned off, the first sub-switch is turned off, the second sub-switch is turned off, and the reference switch is turned off, or switches from the first state in a third state in which the main switch is turned off, the first sub-switch is turned off, the second sub-switch is turned on, and the reference switch is turned off.

10. The control unit, Obtain print data, Based on the aforementioned print data, the controlled element, which is the energy-generating element corresponding to the nozzle that discharges the liquid in the same drive cycle, is identified. The liquid dispensing device according to claim 6, wherein, after charging the plurality of energy-giving elements by applying a voltage to the second electrode with the main power supply, the energy is discharged from the plurality of energy-giving elements, and the energy is regenerated to the first sub-power supply, the second sub-power supply, and either the first sub-power supply or the second sub-power supply, depending on the number of controlled elements.

11. The liquid dispensing device according to claim 1, wherein the potential difference between the main power supply and the first sub-power supply is smaller than the potential difference between the reference potential and the potential of the first sub-power supply.

12. The liquid dispensing device according to claim 1, wherein the potential difference between the main power supply and the second sub-power supply is smaller than the potential difference between the reference potential and the potential of the second sub-power supply.

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