Control device, liquid dispensing device, and control method

Abstract

It reduces the mist generated when ejected droplets hit the target object. [Solution] A control device for controlling a liquid discharge head comprising a nozzle hole for discharging pressurized liquid, a valve body for opening and closing the nozzle hole, and a driving means for moving the valve body along the direction in which the liquid is discharged in accordance with the applied voltage, wherein when the valve body is moved by the driving means, a voltage fluctuation is applied to the driving means at a timing in which the valve body resonates with the natural vibration occurring in the valve body when the valve body is separated from the nozzle hole.

Description

[Technical Field]

[0001] The present invention relates to a control device, a liquid ejection device, and a control method. [Background Art]

[0002] Conventionally, a valve-type inkjet head that applies pressure to ink to eject the ink has been known.

[0003] Patent Document 1 discloses a drive control device and a drive method for stably ejecting liquid droplets in a valve-type inkjet head by adjusting an opening amount and an opening time of a valve in accordance with the size of a liquid droplet to be ejected. Specifically, it is disclosed that a large liquid droplet is ejected by lengthening the opening time of the valve, and a large liquid droplet is ejected by merging small liquid droplets during flight through successive short opening times. [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In a valve-type inkjet head, since the method is to apply pressure to ink, a large ejection amount can be achieved, but the ejection speed tends to increase in order to secure a constant ejection amount. When the ejection speed increases, the kinetic energy of the liquid droplets increases, which tends to cause rebound and mist generation when the liquid droplets land on an ejection target.

[0005] Also, even with the device disclosed in Patent Document 1, since large liquid droplets are ejected, mist is likely to be generated when the liquid droplets land on the ejection target.

[0006] Accordingly, in a valve-type inkjet head, it is preferable to reduce mist that is generated when an ejected liquid droplet lands on an ejection target. [Means for Solving the Problem]

[0007] The control device of the present invention is A control device for controlling a liquid discharge head comprising a nozzle hole for discharging pressurized liquid, a valve body for opening and closing the nozzle hole, and a driving means for moving the valve body along the direction in which the liquid is discharged in accordance with the applied voltage, When the valve body moves due to the drive means, a voltage fluctuation is applied to the drive means at a timing when the valve body resonates with the natural vibration occurring in the valve body while it is separated from the nozzle hole.

[0008] Furthermore, the liquid dispensing device of the present invention is A nozzle hole for dispensing pressurized liquid, A valve body that opens and closes the nozzle hole, A driving means for moving the valve body along the direction in which the liquid is discharged in accordance with the applied voltage, The system includes a control means that, when the valve body moves due to the drive means, applies a voltage fluctuation to the drive means at a timing when the valve body resonates with the natural vibration occurring in the valve body while it is separated from the nozzle hole.

[0009] Furthermore, the control method of the present invention is A control method for controlling a liquid discharge head comprising a nozzle hole for discharging pressurized liquid, a valve body for opening and closing the nozzle hole, and a driving means for moving the valve body along the direction in which the liquid is discharged in accordance with the applied voltage, When the valve body moves due to the drive means, a voltage fluctuation is applied to the drive means at a timing when the valve body resonates with the natural vibration occurring in the valve body while it is separated from the nozzle hole. [Effects of the Invention]

[0010] According to the present invention, it is possible to reduce the mist generated when ejected droplets hit the target object. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows an example of a head unit in this embodiment. [Figure 2]This is an explanatory diagram showing an example of a pressurizing mechanism and a moving mechanism. [Figure 3] This block diagram shows an example of a control system for a liquid dispensing device having a head unit, a pressurizing mechanism, and a moving mechanism. [Figure 4] These diagrams illustrate the opening and closing operation of the nozzle opening; (a) shows the closed state, and (b) shows the open state. [Figure 5] This diagram illustrates the behavior of the valve body due to the drive voltage. (a) shows the square wave generated by the drive voltage generation unit, (b) shows the voltage waveform smoothed by the resistor, and (c) shows the operation of the valve body. [Figure 6] This diagram illustrates an example of a method for measuring the natural vibration period. [Figure 7] This is a diagram showing the behavior of the valve body. [Figure 8] This figure shows the ink ejection process when the valve behaves as shown in Figure 7. [Figure 9] This figure shows the drive voltage applied to the actuator in the first embodiment. [Figure 10] Figure 9 is a diagram illustrating the behavior of the valve body when voltage fluctuations are applied, with (a) showing the behavior of the valve body when no voltage fluctuations are applied, (b) showing the natural vibration components of the valve body, (c) showing the applied voltage fluctuations, and (d) showing the behavior of the valve body when voltage fluctuations are applied. [Figure 11] This figure shows the change in the behavior of the valve body. [Figure 12] This figure shows the ink ejection process when the valve behaves as shown in Figure 11. [Figure 13] This figure shows the drive voltage applied to the actuator in the second embodiment. [Figure 14] This figure shows the drive voltage applied to the actuator in the third embodiment. [Figure 15] This figure shows the drive voltage applied to the actuator in the fourth embodiment, where (a) shows the behavior of the valve body when no voltage fluctuation is applied, (b) shows the natural vibration components of the valve body, and (c) shows the applied voltage fluctuation. [Figure 16] It is a diagram showing the drive voltage applied to the actuator in the fifth embodiment. [Figure 17] It is a diagram for explaining the timing at which voltage fluctuation is applied in the fifth embodiment, wherein (a) is a diagram showing the behavior of the valve element in a state where no voltage fluctuation is applied, (b) is a diagram showing the natural vibration component of the valve element, and (c) is a diagram showing the applied voltage fluctuation. [Figure 18] It is a diagram showing the drive voltage applied to the actuator in the sixth embodiment. [Figure 19] It is a diagram showing the drive voltage applied to the actuator in the seventh embodiment, wherein (a) is a diagram showing the behavior of the valve element in a state where no voltage fluctuation is applied, (b) is a diagram showing the natural vibration component of the valve element, and (c) is a diagram showing the applied voltage fluctuation. [Figure 20] It is a diagram showing an example of the configuration of a coating apparatus. [Figure 21] It is a diagram showing an example of arrangement of the coating apparatus on a target object. [Figure 22] It is a schematic diagram of an electrode manufacturing method and an electrode manufacturing apparatus using an inkjet head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description will be omitted. [Configuration of Head Unit] First, the configuration of the head unit in the present embodiment will be described. FIG. 1 is a diagram showing an example of the head unit in the present embodiment.

[0013] As shown in Figure 1, the head unit HU in this embodiment includes a nozzle plate 101 having nozzle holes 102 for ejecting pressurized ink 10, and a valve member 130 for opening and closing the nozzle holes 102. Furthermore, the head unit HU includes a needle 131 connected to the valve member 130, an actuator 132 connected to the needle 131, and a drive control unit 500 for operating the actuator 132. It also includes a sealing member 135 for sealing the pressurized ink 10.

[0014] The head unit HU is an inkjet head unit that ejects ink 10, which is an example of a liquid. The inkjet head unit HU (hereinafter referred to as the head unit) consists of an inkjet head 100 (hereinafter referred to as the head), which is an example of a liquid ejection head, and a drive control unit 500 that controls the driving of the head 100. The drive control unit 500 constitutes an example of a control device in the present invention. The head 100 comprises a hollow housing 110 and a nozzle plate 101 provided at one end of the housing 110. The nozzle plate 101 is a plate-shaped member in which nozzle holes 102 for ejecting ink 10 are formed.

[0015] The housing 110 is provided with an injection port 113 on the side closest to the nozzle hole 102 for injecting ink 10. The ink 10 injected from the injection port 113 is contained in a liquid chamber 114 inside the housing 110. The liquid chamber 114 is generally formed by a space created between the nozzle plate 101 and a sealing member 135 provided inside the housing 110.

[0016] A needle 131, which is an example of a valve body, is provided inside the liquid chamber 114. A valve member 130 is joined to the tip of the needle 131 on the side where the nozzle plate 101 is located, so as to face the nozzle hole 102. The valve member 130 is made of an elastic material such as rubber or resin. By providing the valve member 130 at the tip of the needle 131, the airtightness to the nozzle hole 102 is improved, and the nozzle hole 102 can be closed more reliably. However, the configuration of the needle 131 is not limited to the above. For example, the nozzle hole 102 may be closed directly by the tip of the needle 131 without providing the valve member 130.

[0017] The sealing member 135 is made of an elastic material such as rubber. In this embodiment, a rubber O-ring is used as the sealing member 135, and the O-ring is fitted onto the needle 131 so as to seal the gap between the inner surface of the housing 110 and the outer surface of the needle 131. As a result, the sealing member 135 prevents the ink 10 in the liquid chamber 114 from flowing into the actuator 132.

[0018] An actuator 132, which is an example of a driving means, is provided in a space formed next to the liquid chamber 114 (above in Figure 1) with respect to the sealing member 135. The actuator 132 moves the needle 131 in the direction of arrow D in Figure 1 between a position that closes the nozzle hole 102 and a position that opens the nozzle hole 102, in response to a drive signal from the drive control unit 500. In the position that closes the nozzle hole 102, the valve member 130 is in contact with the nozzle plate 101, and in the position that opens the nozzle hole 102, the valve member 130 is separated from the nozzle plate 101. In the case of a configuration without a valve member 130, in the position that closes the nozzle hole 102, the needle 131 is in contact with the nozzle plate 101, and in the position that opens the nozzle hole 102, the needle 131 is separated from the nozzle plate 101.

[0019] The actuator 132 is a piezoelectric element formed using zirconia ceramics or the like, and its shape and other properties are appropriately set according to the amount of ink droplets to be ejected. The actuator 132 drives the needle 131 in accordance with the voltage from the drive signal from the drive control unit 500.

[0020] The drive control unit 500 is electrically connected to the actuator 132 and controls the drive of the actuator 132.

[0021] [Configuration of the pressurizing mechanism and the moving mechanism] Next, a pressurizing mechanism for supplying ink 10 to the head 100 under pressure and a moving mechanism for moving the head 100 relative to the object will be described. Figure 2 is an explanatory diagram showing an example of the pressurizing mechanism and the moving mechanism. Figure 3 is a block diagram showing an example of the control system of a liquid ejection device having a head unit, a pressurizing mechanism and a moving mechanism.

[0022] As shown in Figure 2, the ink 10 ejected from the print head 100 is contained in a sealed ink tank 202. The ink tank 202 and the ink inlet 113 of the print head 100 are connected by a tube 201.

[0023] The ink tank 202 is connected to the compressor 205 via a pipe 203 that includes an air regulator 204. The air regulator 204 adjusts the pressure of the compressed air generated by the compressor 205 to the required air pressure and supplies the pressurized air from the compressor 205 to the ink tank 202.

[0024] As a result, pressurized ink 10 is supplied to the liquid chamber 114 of the head 100, and the valve member 130 separates from the nozzle plate 101, allowing the liquid chamber 114 and the nozzle hole 102 to communicate, and the ink 10 is ejected from the nozzle hole 102.

[0025] Here, the tube 201, ink tank 202, pipe 203, air regulator 204, and compressor 205 constitute a pressurizing mechanism 200 for supplying pressurized ink 10 to the liquid chamber 114 of the head 100. The pressurizing mechanism 200 is an example of a pressurizing means.

[0026] Furthermore, a portion of the housing 110 of the head 100 (the upper part in Figure 2) is held by the head holding member 301. The head holding member 301 is connected to a drive unit 302, and by driving the drive unit 302, the head holding member 301 can move along the rail member 303 in the directions of arrows A and B in Figure 2. As a result, the head 100 held by the head holding member 301 also moves along the rail member 303 in the directions of arrows A and B in Figure 2.

[0027] Here, the head holding member 301, the drive device 302, and the rail member 303 constitute a head moving mechanism 300 for moving the head 100 relative to the object. The head moving mechanism 300 is an example of a moving means.

[0028] The drive unit 302 and rail member 303 may be appropriately configured using well-known mechanisms such as a feed screw mechanism using a ball screw, a feed mechanism using a rack and pinion, or a feed mechanism using a power transmission belt and pulley.

[0029] Here, the pressurizing mechanism 200, the head moving mechanism 300, and the head unit HU (head 100, drive control unit 500) connected thereto are an example of a liquid dispensing device.

[0030] Furthermore, as shown in Figure 3, the head unit HU, the pressurizing mechanism 200, and the head moving mechanism 300 are electrically connected to the control unit 600. The control unit 600 may, for example, control the overall operation of the coating apparatus described later, and additional components may be added as needed, in addition to the components shown in the figure.

[0031] The control unit 600 transmits, for example, an ink ejection cycle signal based on image data to the drive control unit 500 of the head unit HU. The control unit 600 receives status information of the head 100, etc., via the drive control unit 500. The control unit 600 also transmits a switching signal to the pressurizing mechanism 200 to switch pressurization on and off. The control unit 600 also transmits a movement signal to the head moving mechanism 300 to move the head 100. Furthermore, the control unit 600 outputs a micro-drive signal to micro-drive the valve body.

[0032] The drive control unit 500 of the head unit HU includes an input unit 501, a drive voltage generation unit 502, an amplification unit 503, and an output unit 504.

[0033] The input unit 501 receives ink ejection cycle signals and the like based on image data from the control unit 600. The input unit 501 also receives micro-drive signals output from the control unit 600.

[0034] The drive voltage generation unit 502 generates a drive voltage to drive the actuator 132 of the head 100 in accordance with information such as the ink ejection cycle signal received by the input unit 501. In addition, the drive voltage generation unit 502 adds voltage fluctuations to the drive voltage to finely drive the valve body in accordance with the fine drive signal received by the input unit 501.

[0035] The amplification unit 503 amplifies the drive voltage generated by the drive voltage generation unit 502 and outputs the amplified signal to the output unit 504.

[0036] The output unit 504 receives the signal amplified by the amplification unit 503 via the resistor 505 and applies a drive voltage to the actuator 132 based on the received signal. The resistor 505 is placed between the amplification unit 503 and the output unit 504 for reasons such as suppressing heat generation in the actuator 132 and ensuring durability against mechanical failure.

[0037] Each of the functions, such as the input unit 501, the drive voltage generation unit 502, the amplification unit 503, and the output unit 504, can be implemented by electrical circuits, or some of these functions can be implemented by software (CPU: Central Processing Unit). Furthermore, each of the above functions may be implemented by multiple circuits or multiple software programs.

[0038] As described above, the drive control unit 500 generates a drive signal based on the ink ejection cycle signal received from the control unit 600, and drives the head 100 using the generated drive signal. The head 100 opens and closes the nozzle holes 102 in response to the drive signal from the drive control unit 500 and ejects ink.

[0039] The pressurizing mechanism 200 switches the compressor 205 (or air regulator 204) on and off based on a switching signal received from the control unit 600, thereby switching the ink 10 sent to the liquid chamber 114 between a pressurized state and an unpressurized state.

[0040] Based on a movement signal received from the control unit 600, the head movement mechanism 300 drives the drive unit 302 in a predetermined direction by a predetermined distance, moving the head 100 to a desired position via the head holding member 301.

[0041] [Opening and closing of the nozzle opening] Next, the opening and closing operation of the nozzle hole 102 will be described.

[0042] Figure 4 is a diagram illustrating the opening and closing operation of the nozzle hole 102, where (a) shows the closed state and (b) shows the open state.

[0043] When a drive voltage is applied to the actuator 132 from the drive control unit 500, the valve member 130 is in contact with the nozzle plate 101 when a closing voltage is applied to the actuator 132, as shown in Figure 4(a). As a result, the valve member 130 is closed by the nozzle hole 102, and the ink 10 in the liquid chamber 114 is not ejected from the nozzle hole 102.

[0044] On the other hand, when an open-circuit voltage is applied to the actuator 132, as shown in Figure 4(b), the actuator 132 contracts, and the actuator 132 moves the needle 131 upward in the figure. This movement of the needle 131 causes the valve member 130, which is joined to the needle 131, to move to a position away from the nozzle plate 101, and a gap G is formed between the tip of the valve member 130 and the nozzle hole 102. Since the ink 10 in the liquid chamber 114 is supplied under pressure at a predetermined pressure by the pressurization mechanism 200, as the gap G is formed, the ink 10 in the liquid chamber 114 is ejected from the nozzle hole 102 as ink droplets 11.

[0045] In this manner, when a drive voltage (closing voltage, opening voltage) is applied to the actuator 132, the valve member 130 moves between a position in contact with the nozzle plate 101 and a position separated from it (in the direction of arrow C in Figure 4(b)), and the valve member 130 opens and closes the nozzle hole 102.

[0046] [Explanation of operation] First, let's explain the basic operation.

[0047] Figure 5 is a diagram illustrating the behavior of the valve body due to the drive voltage, where (a) is the rectangular wave generated by the drive voltage generation unit 502, (b) is the voltage waveform smoothed by the resistor 505, and (c) shows the operation of the valve body. In Figure 5(c), the operation when the nozzle hole 102 moves from the open state to the closed state is shown, and y=0 indicates the closed state.

[0048] In this example, Nozzle hole diameter 102: 100 μm Valve member 130: Fluorine-based resin Ink 10: Paint with a viscosity of approximately 20 cp Applied pressure: 0.3 MPa Drive voltage generation: Digital Discovery (manufactured by Digilent Inc.) Value of resistor 505: 100Ω Discharge waveform frequency: 1000Hz Duty: 50% Closure voltage: 72V Open-circuit voltage: 0V That's what I decided.

[0049] In the head unit HU configured as described above, the actuator 132 extends or retracts in response to an applied voltage corresponding to an electrical signal from the drive control unit 500. The needle 131 and valve member 130 connected to the actuator 132 then move perpendicular to the nozzle plate 101 to open and close the nozzle hole 102. Since pressure is constantly applied to the ink 10 by the pressurizing mechanism 200, when the nozzle hole 102 is open, the ink 10 will be ejected from the nozzle hole 102.

[0050] In this example, the waveform generated by the drive voltage generation unit 502 is a square wave. When an open-circuit voltage (Low) is applied, the actuator 132 contracts, separating the valve body from the nozzle plate 101 and opening the nozzle hole 102. When a closed-circuit voltage (High) is applied, the actuator 132 extends, causing the valve body to contact the nozzle plate 101 and closing the nozzle hole 102. However, the nozzle hole 102 may also be closed when a voltage less than or equal to the closing voltage is applied.

[0051] Here, the lift amount refers to the gap between the nozzle plate 101 and the valve body when they are separated. In this study, the lift amount is approximately several tens of micrometers.

[0052] Even if a rectangular wave like the one shown in Figure 5(a) is generated as the drive waveform by the drive voltage generation unit 502, the waveform of the voltage applied to the actuator 132 is distorted by the resistor 505, as shown in Figure 5(b).

[0053] Therefore, the valve body behaves in a curved manner, as shown in Figure 5(c). The reasons for adding resistance, as mentioned above, include suppressing heat generation in the actuator 132 and ensuring durability against mechanical failure.

[0054] Furthermore, it is known that the valve body, consisting of a needle 131 connected to the actuator 132 and a valve member 130, vibrates slightly with a natural period T0. This is called natural vibration. When the valve body is driven by the drive control unit 500, it vibrates with a natural period T0 while separated from the nozzle plate 101.

[0055] In this example, the natural vibration of the valve body when mounted on the head unit (HU) has a natural frequency of approximately 8 to 12 kHz. The behavior and natural period of the valve body can be measured using a laser Doppler displacement meter.

[0056] Figure 6 illustrates an example of a method for measuring the natural vibration period.

[0057] The natural vibration period T0 of the needle 131 can be determined by measuring the surface of the needle 131 that contacts the nozzle plate 101 (in this embodiment, the end face of the valve member 130 joined to the needle 131).

[0058] As shown in Figure 6, a laser Doppler displacement meter 901 can be used for measurement. In this case, the laser beam 902 emitted from the laser Doppler displacement meter 901 is irradiated onto the end face of the valve member 130 that is to be measured. The natural vibration period T0 can be determined by performing a Fourier analysis on the obtained measurement values.

[0059] Furthermore, if the laser beam 902 emitted from the laser Doppler displacement meter 901 is directed towards the nozzle hole 102, it may be obstructed by the ink droplets 11A ejected from the nozzle hole 102 during measurement, making it impossible to accurately measure the object being measured. Therefore, the laser beam 902 is directed away from the position of the nozzle hole 102. However, the nozzle plate 101 actually used is not made of a material that allows the laser beam 902 to pass through. Therefore, as described above, if the laser beam 902 is directed away from the position of the nozzle hole 102, the problem arises that the laser beam 902 may not reach the object being measured.

[0060] Therefore, during measurement, the nozzle plate 101 is replaced with one made of a material that allows the laser beam 902 to pass through, so that the laser beam 902 can reach the object to be measured. The nozzle plate 101 can be made of any material that allows the laser beam 902 to pass through, and the material is not particularly limited, but glass is preferred from the viewpoint of laser beam 902 transmittance and component rigidity.

[0061] Furthermore, the ink 10A used for measurement is a transparent ink that allows light to pass through, because if it is the actual ink 10, for example, the filler components contained in the ink 10 would hinder the transmission of the laser light 902. However, it is preferable to use an ink 10A that has kinematic viscosity characteristics equivalent to the actual ink 10 for measurement.

[0062] Alternatively, a deflection device 903 that changes the direction of the ink droplet 11A may be installed between the laser Doppler displacement meter 901 and the head 100. The deflection device 903 consists of, for example, a blower fan, which blows air onto the ink droplet 11A in a direction that moves the ink droplet 11A away from the optical path of the laser beam 902. This makes it possible to avoid interference with measurements by the ink droplet 11A and contamination of the laser Doppler displacement meter 901.

[0063] The following describes the ink ejection process.

[0064] Figure 7 shows the behavior of the valve body, and Figure 8 shows the ink ejection when the valve body behaves as shown in Figure 7.

[0065] When the pressurized ink 10 opens the nozzle hole 102 due to the valve, it is discharged as a liquid column from the nozzle hole 102. At this time, as shown in Figure 7, the amount of ink 10 discharged is suppressed when the valve vibrates slightly in the direction of the nozzle hole 102 due to the valve's natural vibration. As a result, the liquid column discharged from the nozzle hole 102 has a constriction, as shown in Figure 8, and the discharge shape is roughly that of a series of spheres.

[0066] In this case, the approximately spherical tip of the liquid column is susceptible to air resistance, and when the valve body closes, in addition to the constantly applied pressure, pressure is also applied as the valve body pushes the ink out, resulting in a slower velocity for the approximately spherical tip of the liquid column than for the approximately spherical tip at the rear end of the liquid column.

[0067] Therefore, as shown in Figure 8, the connected spherical shapes tend to merge during flight, eventually landing as a single spherical droplet. Specifically, as shown in Figure 8, a roughly spherical droplet D1 ejected at t11 ​​merges with a roughly spherical droplet D2 ejected at t12 at t14, and further merges with a roughly spherical droplet D3 ejected at t13 at t15. In this case, if the ejection amount Mj per ink drop and the droplet velocity Vj are large, the kinetic energy of the droplet increases, causing rebound mist to be generated upon impact with the target object, leading to a decrease in print quality.

[0068] (First Embodiment) Figure 9 shows the drive voltage applied to the actuator 132 in the first embodiment.

[0069] As shown in Figure 9, in this embodiment, while an open-circuit voltage (Low) is applied to the actuator 132 to open the nozzle hole 102, a voltage fluctuation is applied to the actuator 132 to finely drive the valve body. Note that the voltage fluctuation in this embodiment is the same as the closed-circuit voltage (High) for closing the nozzle hole 102.

[0070] Figure 10 is a diagram illustrating the behavior of the valve body when voltage fluctuations are applied as shown in Figure 9. (a) shows the behavior of the valve body when no voltage fluctuations are applied, (b) shows the natural vibration components of the valve body, (c) shows the applied voltage fluctuations, and (d) shows the behavior of the valve body when voltage fluctuations are applied.

[0071] In the case where no voltage fluctuation is applied, the actuator 132 that drives the valve body behaves as shown in Figure 10(a). However, as shown in Figure 10(c), a voltage fluctuation is applied to the actuator 132 at a timing that resonates with the natural vibration of the valve body having a period as shown in Figure 10(b). The application of the voltage fluctuation to the actuator 132 is performed in accordance with a micro-drive signal output from the control unit 600 to the drive control unit 500. That is, the control unit 600 outputs a micro-drive signal at a timing that resonates with the natural vibration of the valve body.

[0072] As shown in Figure 10(d), at the timing when the voltage fluctuation is applied, the amplitude due to the natural vibration of the valve body increases due to the resonance effect of the added minute drive signal.

[0073] Figure 11 shows the change in the behavior of the valve body, and Figure 12 shows the ink ejection when the valve body behaves as shown in Figure 11.

[0074] When the aforementioned voltage fluctuations are applied at all resonance timings of the valve body's natural vibration, the minute amplitude due to the natural vibration becomes smaller than the amplitude of the valve body without the applied voltage fluctuations (solid line), as shown by the dashed line in Figure 11.

[0075] In this case, the liquid column ejected from the nozzle hole 102 has a constriction, as shown in Figure 12, and the ejection shape is that of a series of roughly spherical droplets. If no voltage fluctuation is applied, the droplet velocity of the second to fifth droplets D2 to D5 of the roughly spherical shape shown in Figure 12 will increase due to the increased lift amount of the valve body or the increase in pressure when the nozzle 102 closes. However, in this embodiment, a voltage fluctuation is applied to slightly drive the valve body at a timing that resonates with the natural vibration of the valve body, thereby increasing the amplitude of the natural vibration of the valve body. As a result, a timing occurs in the behavior of the valve body where the lift amount decreases (t11~t15 in Figure 11), which acts to inhibit the ejection of ink 10 and reduces the droplet velocity of the second droplet D2 and subsequent droplets. In addition, the liquid (liquid column) between the roughly spherical droplets can be made narrower (the constriction can be increased), and the attractive force between droplets due to the surface tension of the liquid column can be reduced.

[0076] As a result, as shown in Figure 12, the approximately spherical droplets D1 to D5 do not completely merge before impact, and instead, the approximately spherical droplets remain connected, impacting each other with a time difference.

[0077] This process reduces the mass of each individual droplet and thus the kinetic energy compared to when several nearly spherical droplets merge to form a single sphere. As a result, it is possible to enhance the suppression of ricochet mist upon impact and improve print quality.

[0078] Thus, when a voltage fluctuation for finely driving the valve body is applied to the open-circuit voltage for opening the nozzle hole 102, the rebound mist suppression effect can be enhanced by making the fine-driving signal output from the control unit 600 resonate with the natural vibration of the valve body. In this case, the timing of resonance is such that, at the nth resonance timing of the natural vibration of the valve body, the timing of turning the fine-driving signal ON is t1 and the timing of turning the fine-driving signal OFF is t2. For example, in the waveform shown in the graph in Figure 10, T0 × n + T0 × 0.25 ≤ t1 <t2≦T0×n+T0×0.75 This refers to the timing of the micro-drive signal that amplifies the natural vibration of the valve body. T0 is the period of the valve body's natural vibration. The timing of turning the micro-drive signal ON is the timing when the voltage fluctuation begins, and the timing of turning the micro-drive signal OFF is the timing when the voltage fluctuation ends.

[0079] (Second embodiment) Figure 13 shows the drive voltage applied to the actuator 132 in the second embodiment.

[0080] As shown in Figure 13, in this embodiment, the voltage fluctuation applied to finely drive the valve body is set to a voltage smaller than the voltage difference between the closing voltage (High) for closing the nozzle hole 102 and the opening voltage (Low) for opening the nozzle hole 102. In this case, the voltage fluctuation is applied to the opening voltage (Low) for opening the nozzle hole 102.

[0081] By applying such voltage fluctuations, the decrease in the lift amount can be suppressed, and the decrease in the ink ejection amount Mj of ink 10 can be suppressed.

[0082] (Third embodiment) Figure 14 shows the drive voltage applied to the actuator 132 in the third embodiment.

[0083] As shown in Figure 14, in this embodiment, when an open-circuit voltage (Low) is applied to open the nozzle hole 102, voltage fluctuations are applied multiple times at timings that resonate with the natural vibration of the valve body in order to slightly drive the valve body. In this case, a slight drive signal for slightly driving the valve body is input multiple times from the control unit 600 to the drive control unit 500 at timings that resonate with the natural vibration of the valve body, and voltage fluctuations for slightly driving the valve body are applied to the drive voltage output from the drive control unit 500. In this embodiment as well, voltage fluctuations are applied to the open-circuit voltage (Low) for opening the nozzle hole 102.

[0084] By applying such voltage fluctuations, it is possible to create many constrictions between the approximately spherical droplets, as shown in Figure 12.

[0085] (Fourth embodiment) Figure 15 shows the drive voltage applied to the actuator 132 in the fourth embodiment, where (a) shows the behavior of the valve body when no voltage fluctuation is applied, (b) shows the natural vibration components of the valve body, and (c) shows the applied voltage fluctuation.

[0086] As shown in Figure 15, in this embodiment, the voltage fluctuation applied to finely drive the valve body is increased at a timing that resonates with the natural vibration of the valve body, and then a voltage lower than the open-circuit voltage required to open the nozzle hole 102 is applied. Specifically, for the actuator 132 that drives the valve body, whose behavior when no voltage fluctuation is applied is as shown in Figure 15(a), the voltage is increased at a timing t1 that resonates with the natural vibration of the valve body having a period as shown in Figure 15(b), as shown in Figure 15(c). This timing t1 is the timing when the open-circuit voltage required to open the nozzle hole 102 is applied to the actuator 132. Then, at a timing t2 that resonates with the natural vibration of the valve body, a voltage lower than the open-circuit voltage required to open the nozzle hole 102 is applied. After that, at a timing t3 that resonates with the natural vibration of the valve body, the voltage is returned to the open-circuit voltage required to open the nozzle hole 102.

[0087] In this case, if t3 is the timing at which this voltage fluctuation ends after applying a voltage lower than the open-circuit voltage required to open the nozzle hole 102, i.e., the timing at which the applied voltage is returned to the open-circuit voltage, then at the nth resonance timing of the valve body's natural vibration, T0 × n + T0 × 0.75 ≤ t3 ≤ T0 × n + T0 × 1.25 This is preferable. Note that T0 is the period of the valve body's natural vibration.

[0088] By applying such voltage fluctuations, the lift amount is reduced and then increased, which helps to suppress the decrease in the discharge volume Mj.

[0089] (Fifth embodiment) Figure 16 shows the drive voltage applied to the actuator 132 in the fifth embodiment. Figure 17 is a diagram illustrating the timing of the voltage fluctuation in the fifth embodiment, where (a) shows the behavior of the valve body when no voltage fluctuation is applied, (b) shows the natural vibration components of the valve body, and (c) shows the applied voltage fluctuation.

[0090] As shown in Figures 16 and 17, in this embodiment, a voltage fluctuation is applied to the closing voltage for closing the nozzle hole 102 at a time t0 that has elapsed since the start of applying the open-circuit voltage for opening the nozzle hole 102. In this case, while the valve body is moving in the direction of closing the nozzle hole 102 due to the closing voltage applied to the actuator 132, a voltage fluctuation is applied to finely drive the valve body. This is done by outputting a fine-driving signal from the control unit 600 at a timing that resonates with the natural vibration of the valve body while the closing voltage for closing the nozzle hole 102 is applied to the actuator 132. Specifically, while the closing voltage is applied, a voltage fluctuation is applied to the actuator 132, which drives the valve body as shown in Figure 17(a), at a timing t1 that resonates with the natural vibration of the valve body with the period shown in Figure 17(b), as shown in Figure 17(c). Subsequently, the application of the voltage fluctuation is terminated at a timing t2 that resonates with the natural vibration of the valve body. The application of voltage fluctuations is performed in accordance with the minute drive signal output from the control unit 600, as in the embodiment described above.

[0091] In this embodiment, while the valve body is moving in the direction of closing the nozzle hole 102, a minute drive signal is input to the actuator 132 in the direction of lowering the voltage applied to it, thereby introducing a voltage fluctuation. This suppresses the velocity of the droplets at the rear end of the liquid column that constitute the liquid column as shown in Figure 12, and prevents the merging of the droplets at the front end and the droplets at the rear end.

[0092] (Sixth embodiment) Figure 18 shows the drive voltage applied to the actuator 132 in the sixth embodiment.

[0093] As shown in Figure 18, in this embodiment, while a closing voltage is applied to close the nozzle hole 102, voltage fluctuations are applied multiple times at timings that resonate with the natural vibration of the valve body to slightly drive the valve body. The application of the closing voltage to close the nozzle hole 102 starts at a time t0 that has elapsed since the start of the application of the opening voltage to open the nozzle hole 102. In this case, a slight drive signal for slightly driving the valve body is input multiple times from the control unit 600 to the drive control unit 500 at timings that resonate with the natural vibration of the valve body, and voltage fluctuations for slightly driving the valve body are added to the drive voltage output from the drive control unit 500. Also in this embodiment, while the valve body is moving in the direction of closing the nozzle hole 102 due to the application of a closing voltage to the actuator 132, voltage fluctuations for slightly driving the valve body are applied. The voltage fluctuations for slight driving may be smaller than the voltage difference between the closing voltage and the opening voltage.

[0094] This configuration allows for fine-tuning of the numerous constrictions between the approximately spherical droplets, as shown in Figure 12, further suppressing the velocity of the droplets at the rear end and preventing droplet coalescence. Furthermore, by not reducing the drive voltage applied to the actuator 132 to the open-circuit voltage, an increase in the discharge volume Mj can be suppressed.

[0095] (Seventh Embodiment) Figure 19 shows the drive voltage applied to the actuator 132 in the seventh embodiment, where (a) shows the behavior of the valve body when no voltage fluctuation is applied, (b) shows the natural vibration components of the valve body, and (c) shows the applied voltage fluctuation.

[0096] As shown in Figure 19, in this embodiment, the voltage fluctuation applied to finely drive the valve body is such that the voltage is reduced at a timing that resonates with the natural vibration of the valve body, and then a voltage higher than the closing voltage required to close the nozzle hole 102 is applied. Specifically, for the actuator 132 that drives the valve body, whose behavior when no voltage fluctuation is applied is shown in Figure 19(a), first, as shown in Figure 19(c), the voltage is reduced at a timing t1 that resonates with the natural vibration with the period shown in Figure 19(b). This timing t1 is the timing when the closing voltage required to close the nozzle hole 102 is applied to the actuator 132. Then, at a timing t2 that resonates with the natural vibration of the valve body, a voltage higher than the closing voltage required to close the nozzle hole 102 is applied. After that, at a timing t3 that resonates with the natural vibration of the valve body, the voltage is returned to the closing voltage required to close the nozzle hole 102.

[0097] By applying such voltage fluctuations, the lift amount is increased and then decreased, which can suppress the increase in the discharge volume Mj.

[0098] Furthermore, when applying voltage fluctuations to the closing voltage as shown in the fifth to seventh embodiments, the rebound mist suppression effect can be enhanced by making the micro-drive signal output from the control unit 600 resonate with the natural vibration of the valve body. In this case, the timing of resonance is such that, at the nth resonance timing of the natural vibration of the valve body, the timing of turning the micro-drive signal ON is t1 and the timing of turning the micro-drive signal OFF is t2. For example, in the waveform shown in the graph in Figure 19, t0 <T0×n+T0×0.25≦t1<t2≦T0×n+T0×0.75 This refers to the timing of the micro-drive signal that amplifies the natural vibration of the valve body. T0 is the period of the natural vibration of the valve body. The timing to turn the micro-drive signal ON is the timing to start applying the voltage fluctuation, and the timing to turn the micro-drive signal OFF is the timing to stop applying the voltage fluctuation. Furthermore, t0 is the elapsed time from the start of applying the open voltage to open the nozzle hole 102 to the start of applying the closed voltage to close the nozzle hole 102, as shown in Figures 16 and 18.

[0099] Furthermore, in the seventh embodiment, if the timing at which this voltage fluctuation ends after applying a voltage higher than the closing voltage for closing the nozzle hole 102 is set to t3, then at the nth resonance timing of the valve body's natural vibration, T0 × n + T0 × 1.25 ≤ t3 ≤ T0 × n + T0 × 1.75 It is preferable to do so. Note that T0 is the period of the valve body's natural vibration. Furthermore, the timing to end this voltage fluctuation after applying a voltage higher than the closing voltage required to close the nozzle hole 102 is the timing to return the applied voltage to the closing voltage.

[0100] This allows for the amplification of the valve's natural vibration while suppressing changes in the amount of ink 10 dispensed, thereby increasing the constriction between the approximately spherical droplets as shown in Figure 12.

[0101] [Coating device] Next, we will explain an example of applying the coating device to the head unit HU described above to a vehicle body painting system.

[0102] Figure 20 shows an example of the configuration of the coating apparatus 1001. Figure 21 shows an example of the placement of the coating apparatus 1001 on the object U.

[0103] The coating apparatus 1001 includes the head 100 and control unit 600 described above. The coating apparatus 1001 also includes a camera 1004 as an imaging means disposed near the head 100, and an XY table 1003 for moving the head 100 and camera 1004 in the X and Y directions.

[0104] The control unit 600 operates the XY table 1003 and discharges liquid from the head 100 based on a predetermined control program. The coating device 1001 can apply the liquid discharged by the head 100 to the target object U.

[0105] The head 100 discharges liquid from multiple nozzles toward the surface of the object U to be coated. The liquid discharged from the nozzles is directed approximately perpendicular to the XY plane. The discharge directions of the liquid from each of the multiple nozzles are approximately parallel. The distance between the nozzles and the surface of the object U to be coated is, for example, about 20 cm.

[0106] The XY table 1003 has an X-axis 1005 formed with a linear movement mechanism, and a Y-axis 1006 that moves the X-axis 1005 in the Y direction while holding the X-axis 1005 with two arms. The head 100 and camera 1004 are attached to the slider of the X-axis 1005.

[0107] A shaft 1007 is provided on the Y axis 1006. The coating device 1001 is equipped with a robot arm 1008, and by holding the shaft 1007 in the robot arm 1008, the head 100 can be freely positioned relative to the object U.

[0108] For example, if the object U is a car, the robot arm 1008 can be positioned above the object U as shown in Figure 21(a), or to the side of the object U as shown in Figure 21(b).

[0109] The control unit 600 controls the movement of the robot arm 1008 based on a predetermined program, but another control device may be responsible for controlling the robot arm 1008.

[0110] The camera 1004 is mounted on a slider of the X-axis 1005, near the head 100, and moves in the XY direction to photograph a predetermined area of ​​the coated surface of the object U at constant minute intervals. The camera 1004 is, for example, a digital camera.

[0111] In the camera 1004, specifications such as lens specifications or resolution are appropriately selected to enable the capture of multiple subdivided images of a predetermined area of ​​the surface to be coated. The capture of multiple subdivided images of the surface to be coated by the camera 1004 is performed continuously and automatically according to a program pre-programmed in the control unit 600.

[0112] The coating apparatus 1001 is equipped with software S for editing images captured by the camera 1004, and the computer in the control unit 600 executes the software S. Note that the image editing by the software S may be handled by another computer. The control unit 600 controls the voltage applied to the head 100 based on the image edited by the software. The coating apparatus 1001 also includes a monitor 1010 that displays the image edited by the software S.

[0113] The coating device 1001, having a robot arm 1008 and a head 100, can apply liquid to a desired position on the object U with high precision, even when the distance between the object U and the nozzle is long.

[0114] Since the control unit 600 can reduce variations in the discharge volume between channels of the head 100, the coating device 1001 can apply the liquid evenly and uniformly to the target object U.

[0115] Furthermore, the control unit 600 can improve the durability of the valve body by suppressing excessive pushing of the valve body into the nozzle plate of the head 100. In addition, the control unit 600 suppresses variations in the amount of valve body pushing between channels, thereby suppressing variations in the durability of the valve body and reducing the frequency of maintenance. Consequently, the downtime of the coating device 1001 can be reduced, contributing to improved productivity of the target object U.

[0116] [Electrode manufacturing method] Next, a method and apparatus for manufacturing electrodes using the head 100 described above will be explained.

[0117] Figure 22 is a schematic diagram of an electrode manufacturing method and electrode manufacturing apparatus using head 100. The electrode manufacturing apparatus is a device that manufactures electrodes having an electrode material layer by discharging a liquid composition using head 100.

[0118] <Means for forming electrode material layer and process for forming electrode material layer> By discharging liquid from the head 100, which acts as a discharging means, a liquid composition can be applied to an object to form a liquid composition layer. The object is not particularly limited as long as it is an object on which an electrode material layer is to be formed, and can be appropriately selected according to the purpose. Examples of objects include an electrode substrate (current collector), an active material layer, or a layer having a solid electrode material.

[0119] The dispensing means and dispensing process may be configured to form an electrode material layer on the target object by directly dispensing the liquid composition, or by indirectly dispensing the liquid composition, as long as it is possible to form an electrode material layer on the target object.

[0120] <Other configurations and processes> Other components in the electrode composite layer manufacturing apparatus are not particularly limited as long as they do not impair the effects of the present invention and can be appropriately selected according to the purpose, for example, a heating means. Other steps in the method for manufacturing the electrode composite layer are not particularly limited as long as they do not impair the effects of the present invention and can be appropriately selected according to the purpose, for example, a heating step.

[0121] <Heating means and heating process> The heating means is a means for heating the liquid composition discharged by the discharge means. The heating step is a step of heating the liquid composition discharged in the discharge step. Heating can dry the liquid composition layer.

[0122] Here, as an example of an electrode manufacturing method, we will describe an electrode manufacturing method in which an electrode composite layer containing an active material is formed on an electrode substrate (current collector).

[0123] As shown in Figure 22(a), the electrode composite layer manufacturing apparatus comprises a dispensing section 110g and a heating section 130g. The dispensing section 110g applies a liquid composition onto a printing substrate 4g having an object to be processed to form a liquid composition layer. The heating section 130g heats the liquid composition layer to obtain an electrode composite layer.

[0124] The electrode composite layer manufacturing apparatus includes a transport unit 5 for transporting 4g of printing substrate, and the transport unit 5 transports the 4g of printing substrate at a preset speed in the order of discharge process 110g and heating process 130g. Examples of the transport unit 5 include transport rollers and transport conveyors.

[0125] There are no particular restrictions on the method for manufacturing 4g of a printing substrate having an active material layer or the like; known methods can be appropriately selected.

[0126] The discharge process section 110g comprises a printing device 281a, a storage container 281b, and a supply tube 281c.

[0127] The printing apparatus 281a is, for example, a head 100, which performs a dispensing process of applying a liquid composition onto a printing substrate 4g. The containment container 281b is, for example, an ink tank 202, which contains the liquid composition. The supply tube 281c is, for example, a tube 201, which supplies the liquid composition stored in the containment container 281b to the printing apparatus 281a.

[0128] The containment container 281b contains the liquid composition 7, and the dispensing unit 110g dispenses the liquid composition 7 from the printing device 281a to apply the liquid composition 7 onto the printing substrate 4g, forming a thin film layer of the liquid composition.

[0129] The containment container 281b may be integrated with the electrode composite layer manufacturing apparatus, or it may be detachable from the electrode composite layer manufacturing apparatus. Alternatively, the containment container 281b may be a container to which the liquid composition 7 is added, either as a container integrated with the electrode composite layer manufacturing apparatus or as a container detachable from the electrode composite layer manufacturing apparatus.

[0130] The containment container 281b or the supply tube 281c can be any type that can stably store and supply the liquid composition 7.

[0131] The heating process section 130g includes a heating device 3a and includes a solvent removal step in which the solvent remaining in the liquid composition layer is heated and dried by the heating device 3a to remove it. This allows for the formation of an electrode composite layer. The heating process section 130g may perform the solvent removal step under reduced pressure.

[0132] There are no particular restrictions on the heating device 3a, and it can be appropriately selected according to the purpose. Examples include substrate heating, IR heaters, and hot air heaters, and these may be combined. Furthermore, the heating temperature or time can be appropriately selected according to the boiling point of the solvent contained in the liquid composition 7 or the film thickness to be formed.

[0133] As shown in Figure 22(b), the liquid dispensing device 1 is an example of an electrode manufacturing apparatus that realizes a method for manufacturing an electrode composite layer. The liquid dispensing device 1 controls a pump 310 and two valves 311 and 312 to circulate the liquid composition through the head 100, the internal tank 307, and the liquid transfer tube 308.

[0134] The liquid discharge device 1 is also equipped with an external tank 313. When the liquid composition in the internal tank 307 decreases, the liquid composition is supplied from the external tank 313 to the internal tank 307 by controlling the pump 310 and three valves 311, 312, and 314. By using the electrode composite layer manufacturing apparatus, the liquid composition can be discharged to a targeted location on the object.

[0135] The electrode composite layer can be suitably used, for example, as part of the configuration of an electrochemical element. Other components of the electrochemical element besides the electrode composite layer are not particularly limited and known components can be appropriately selected, such as a positive electrode, a negative electrode, and a separator.

[0136] Since the liquid ejection device 1 can reduce variations in the amount of liquid ejected between channels of the printing device 281a, which acts as a liquid ejection head, the printing device 281a can uniformly and evenly apply a liquid composition layer onto the printing substrate 4g, which is the target object.

[0137] Furthermore, the liquid dispensing device 1 can improve the durability of the valve body by suppressing excessive pushing of the valve body into the nozzle plate of the printing device 281a. In addition, the liquid dispensing device 1 suppresses variations in the amount of valve body pushing between channels, thereby suppressing variations in the durability of the valve body and reducing the frequency of maintenance. Consequently, the downtime of the liquid dispensing device 1 as an electrode manufacturing device can be reduced, contributing to improved productivity of the target object U.

[0138] It should be noted that the present invention is not limited to the configurations shown in the above embodiments, including combinations with other elements. These aspects can be modified without departing from the spirit of the present invention and can be appropriately determined according to their application.

[0139] Examples of the present invention are as follows: (Note 1) A control device for controlling a liquid discharge head comprising a nozzle hole for discharging pressurized liquid, a valve body for opening and closing the nozzle hole, and a driving means for moving the valve body along the direction in which the liquid is discharged in accordance with the applied voltage, A control device that, when the valve body moves by the drive means, applies a voltage fluctuation to the drive means at a timing when the valve body resonates with the natural vibration occurring in the valve body while it is separated from the nozzle hole. (Note 2) An open-circuit voltage is applied to the driving means to move the valve body to a position that opens the nozzle hole. The driving means starts applying the voltage fluctuation at a time t1 that has elapsed since the application of the open-circuit voltage. The application of the voltage fluctuation is terminated at a time t2 that has elapsed since the application of the open-circuit voltage. When the period of the natural vibration of the valve body is T0 and n is a natural number, T0 × n + T0 × 0.25 ≤ t1 <t2≦T0×n+T0×0.75 The control device described in Appendix 1. (Note 3) The control device according to Appendix 2, wherein the voltage of the voltage fluctuation is smaller than the voltage difference between the open-circuit voltage and the closing voltage that closes the nozzle hole by the valve body. (Note 4) An open-circuit voltage is applied to the drive means to move the valve body to a position that opens the nozzle hole. A closing voltage is applied to the driving means at a time t0 elapsed since the application of the open-circuit voltage, causing the valve body to move to a position that closes the nozzle hole. The driving means starts applying the voltage fluctuation at a time t1 that has elapsed since the application of the open-circuit voltage. The application of the voltage fluctuation is terminated at a time t2 that has elapsed since the application of the open-circuit voltage. When the period of the natural vibration of the valve body is T0 and n is a natural number, t0 <T0×n+T0×0.25≦t1<t2≦T0×n+T0×0.75 The control device described in Appendix 1. (Note 5) The control device according to Appendix 4, wherein the voltage of the voltage fluctuation is smaller than the voltage difference between the opening voltage that opens the nozzle hole by the valve body and the closing voltage. (Note 6) The control device described in Appendix 4, which applies a voltage fluctuation larger than the closing voltage at a timing after t2. (Note 7) If the timing for ending the application of a voltage fluctuation larger than the aforementioned closing voltage is defined as the elapsed time t3 since the application of the aforementioned open-circuit voltage, T0 × n + T0 × 1.25 ≤ t3 ≤ T0 × n + T0 × 1.75 The control device described in Appendix 6. (Note 8) A nozzle hole for dispensing pressurized liquid, A valve body that opens and closes the nozzle hole, A driving means for moving the valve body along the direction in which the liquid is discharged in accordance with the applied voltage, A control means that, when the valve body moves by the drive means, applies a voltage fluctuation to the drive means at a timing when the valve body resonates with the natural vibration occurring in the valve body while it is separated from the nozzle hole, A liquid dispensing device having the following features. (Note 9) A control method for controlling a liquid discharge head comprising a nozzle hole for discharging pressurized liquid, a valve body for opening and closing the nozzle hole, and a driving means for moving the valve body along the direction in which the liquid is discharged in accordance with the applied voltage, A control method comprising applying a voltage fluctuation to the driving means at a timing when the valve body moves due to the driving means, and the valve body resonates with the natural vibration occurring in the valve body while it is separated from the nozzle hole. [Explanation of Symbols]

[0140] 1 Liquid discharge device 3a Heating device 4g printing substrate 5. Conveying section 7 Liquid composition 10,10A Ink 11,11A Inkdrop 100 inkjet heads 101 Nozzle Plate 102 Nozzle holes 110 cabinets 110g discharge process section 113 Inlet 114 Liquid chamber 130 Valve member 130g heating process section 131 Needle 132 Actuators 135 Sealing member 200 Pressurization mechanism 201 Tube 202 Ink Tank 203 Pipe 204 Air Regulator 205 Compressor 281a Printing device 281b Containment container 281c supply tube 300 Head movement mechanism 301 Head holding member 302 Drive unit 303 Rail component 307 Internal Tank 308 Fluid transfer tube 310 pump 311, 312, 314 valves 313 External Tank 500 Drive Control Unit 501 Input section 502 Drive Voltage Generation Unit 503 Amplifier 504 Output section 505 resistor 600 Control Unit 901 Laser Doppler Displacement Meter 902 Laser light 903 Deflection device 1001 Coating device 1003 XY Table 1004 Camera 1005 X-axis 1006 Y-axis 1007 Shaft 1008 Robot Arm 1010 Monitor G Gap HU Head Unit S Software U Object [Prior art documents] [Patent Documents]

[0141] [Patent Document 1] Japanese Patent Publication No. 2023-128411

Claims

1. A control device for controlling a liquid discharge head comprising a nozzle hole for discharging pressurized liquid, a valve body for opening and closing the nozzle hole, and a driving means for moving the valve body along the direction in which the liquid is discharged in accordance with the applied voltage, A control device that, when the valve body moves by the drive means, applies a voltage fluctuation to the drive means at a timing when the valve body resonates with the natural vibration occurring in the valve body while it is separated from the nozzle hole.

2. An open-circuit voltage is applied to the driving means to move the valve body to a position that opens the nozzle hole. The driving means starts applying the voltage fluctuation at a time t1 that has elapsed since the application of the open-circuit voltage. The application of the voltage fluctuation is terminated at a time t2 that has elapsed since the application of the open-circuit voltage. When the period of the natural vibration of the valve body is T0 and n is a natural number, T0 × n + T0 × 0.25 ≤ t1 < t2 ≤ T0 × n + T0 × 0.75 The control device according to claim 1.

3. The control device according to claim 2, wherein the voltage of the voltage fluctuation is smaller than the voltage difference between the open-circuit voltage and the closing voltage that closes the nozzle hole by the valve body.

4. An open-circuit voltage is applied to the driving means to move the valve body to a position that opens the nozzle hole. A closing voltage is applied to the driving means at a time t0 elapsed since the application of the open-circuit voltage, causing the valve body to move to a position that closes the nozzle hole. The driving means starts applying the voltage fluctuation at a time t1 that has elapsed since the application of the open-circuit voltage. The application of the voltage fluctuation is terminated at a time t2 that has elapsed since the application of the open-circuit voltage. When the period of the natural vibration of the valve body is T0 and n is a natural number, t0<T0×n+T0×0.25≦t1<t2≦T0×n+T0×0.75 The control device according to claim 1.

5. The control device according to claim 4, wherein the voltage of the voltage fluctuation is smaller than the voltage difference between the opening voltage that opens the nozzle hole by the valve body and the closing voltage.

6. The control device according to claim 4, wherein a voltage fluctuation larger than the closing voltage is applied at a timing after t2.

7. If the timing for ending the application of a voltage fluctuation larger than the aforementioned closing voltage is defined as the elapsed time t3 since the application of the aforementioned opening voltage, T0 × n + T0 × 1.25 ≤ t3 ≤ T0 × n + T0 × 1.75 The control device according to claim 6.

8. A nozzle hole for dispensing pressurized liquid, A valve body that opens and closes the nozzle hole, A driving means for moving the valve body along the direction in which the liquid is discharged in accordance with the applied voltage, A control means that, when the valve body moves by the drive means, applies a voltage fluctuation to the drive means at a timing when the valve body resonates with the natural vibration occurring in the valve body while it is separated from the nozzle hole, A liquid dispensing device having the following features.

9. A control method for controlling a liquid discharge head comprising a nozzle hole for discharging pressurized liquid, a valve body for opening and closing the nozzle hole, and a driving means for moving the valve body along the direction in which the liquid is discharged in accordance with the applied voltage, A control method comprising applying a voltage fluctuation to the driving means at a timing when the valve body moves due to the driving means, and the valve body resonates with the natural vibration occurring in the valve body while it is separated from the nozzle hole.

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