A device for dispensing liquid

Abstract

To reduce reduction of sealability of a nozzle caused by foreign objects adhering to a valve body surface.SOLUTION: A head unit includes: a liquid discharge head having a nozzle plate formed with a nozzle, a liquid chamber which houses the liquid to be discharged from the nozzle, a valve body provided within the liquid chamber, a valve body connection member connected to the valve body, and a drive mechanism which drives the valve body connection member so as to move the valve body between a position where the valve body contacts with the nozzle plate and a position where the valve body separates from the nozzle plate to cause the valve body to open or close the nozzle; and a drive control unit which controls driving of the drive mechanism. The drive control unit controls the drive mechanism so as to cause the valve body to vibrate in a state that the valve body separates from the nozzle plate.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention ,liquid relates to a device for discharging a body.

Background Art

[0002] In Patent Document 1, in a liquid ejection head that controls the ejection of ink by pressing a valve body formed to be movable toward an ejection port for ejecting ink, a recess is disposed at a position of the valve body facing the ejection port. A liquid ejection head is described.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is that the sealing performance of the ejection port (nozzle) deteriorates due to foreign matter adhering to the surface of the valve body.

Means for Solving the Problems

[0005] The present invention includes a nozzle plate formed with nozzles, a liquid chamber that stores a liquid to be ejected from the nozzles, a valve body provided in the liquid chamber, a valve body connection member connected to the valve body, and a drive mechanism that moves the valve body between a position in contact with the nozzle plate and a position spaced apart therefrom, and drives the valve body connection member so that the valve body opens and closes the nozzles; and a liquid ejection head, and a drive control unit that controls the drive of the drive mechanism. A device for dispensing a liquid having a pressurizing mechanism for pressurizing the liquid in the liquid chamber, The drive control unit While the pressurizing mechanism is pressurizing the liquid, the valve body is moved between a position in contact with the nozzle plate and a position separated from it to discharge the liquid from the nozzle, and while the pressurizing mechanism is not pressurizing the liquid, separates the valve body from the nozzle plate hand, and controls the drive mechanism so as to vibrate the valve body.

Effects of the Invention

[0006] According to the present invention, it is possible to reduce the decrease in nozzle sealing performance caused by foreign matter adhering to the surface of the valve body. [Brief explanation of the drawing]

[0007] [Figure 1] A diagram showing the configuration of an inkjet head unit as an example of a head unit according to the embodiment. [Figure 2] An explanatory diagram showing an example of a pressurizing mechanism and a moving mechanism. [Figure 3] A block diagram showing an example of the control system for the head unit, pressurizing mechanism, and moving mechanism. [Figure 4] An explanatory diagram showing an example of a head drive waveform. [Figure 5] An explanatory diagram showing the operation of the head unit. [Figure 6] An explanatory diagram showing the operation of the head unit. [Figure 7] An explanatory diagram showing a modified example. [Figure 8] An explanatory diagram showing an example of operation in a device that dispenses liquid. [Figure 9] An explanatory diagram showing a second embodiment of the head unit according to the present invention. [Figure 10] An explanatory diagram showing an example of its application. [Figure 11] An overall perspective view showing an example of a carriage. [Figure 12] An overall perspective view showing an example of a device for dispensing liquid. [Modes for carrying out the invention]

[0008] The embodiments for carrying out the invention will be described below with reference to the drawings. In the description of the drawings, the same elements will be denoted by the same reference numeral, and redundant explanations will be omitted.

[0009] [Head unit configuration] First, referring to FIG. 1, the configuration of an inkjet head unit as an example of a head unit according to an embodiment will be described. FIG. 1 is a cross-sectional view showing the configuration of an inkjet head unit as an example of a head unit according to an embodiment.

[0010] As shown in FIG. 1, an inkjet head unit HU (hereinafter referred to as a head unit) includes an inkjet head 100 (hereinafter referred to as a head) as an example of a liquid ejection head, and a drive control unit 500.

[0011] The head 100 includes a housing 110 formed in a hollow shape, and a nozzle plate 101 provided at one end of the housing 110. Nozzles 102 for ejecting ink 10 as an example of a liquid are formed on the nozzle plate 101.

[0012] In addition, the housing 110 has an injection port 113 for injecting the ink 10 on a side surface near the nozzle 102. The ink 10 injected from the injection port 113 is stored in a liquid chamber 114 in the housing 110.

[0013] The liquid chamber 114 is generally configured by a space formed between the nozzle plate 101 and a sealing member 135 provided in the housing 110. In the liquid chamber 114, a valve body 130 is provided so as to face the nozzle 102 on the side where the nozzle plate 101 is provided. Further, a needle 131 as an example of a valve body connecting member is joined to the valve body 130.

[0014] The sealing member 135 is made of, for example, an O-ring and is externally fitted to the needle 131 so as to seal the gap between the inner surface of the housing 110 and the outer peripheral surface of the needle 131. Thereby, the sealing member 135 prevents the ink 10 in the liquid chamber 114 from flowing into the piezoelectric element 132 side as an example of a drive mechanism.

[0015] The piezoelectric element 132 is provided in a space formed adjacent to the liquid chamber 114 (above in FIG. 1) with the sealing member 135 as a boundary. The piezoelectric element 132 drives the needle 131 so as to move between a position where the valve body 130 contacts the nozzle plate 101 and a position where they are separated, according to a signal (driving waveform) from the drive control unit 500. The opening and closing of the nozzle 102 is performed by the movement of this valve body 130. The piezoelectric element 132 is a piezoelectric element (Piezoelectric element) and is formed using zirconia ceramics or the like. Its shape and the like are appropriately set according to the amount of ink dots to be ejected and the like.

[0016] The drive control unit 500 is electrically connected to the piezoelectric element 132 and controls the drive of the piezoelectric element 132.

[0017] [Configuration of the pressurization mechanism and the movement mechanism] Next, referring to FIGS. 2 and 3, a pressurization mechanism for pressurizing and supplying the ink 10 to the head 100 and a movement mechanism for moving the head 100 will be described. FIG. 2 is an explanatory diagram showing an example of the pressurization mechanism and the movement mechanism, and FIG. 3 is a block diagram showing an example of the control system of the head unit, the pressurization mechanism, and the movement mechanism.

[0018] In FIG. 2, the ink 10 ejected from the head 100 is stored in a sealed liquid (ink) tank 202. The ink tank 202 and the injection port 113 of the head 100 are connected via a tube 201.

[0019] On the other hand, the ink tank 202 is connected to a compressor 205 via a pipe 203 including an air regulator 204. The air regulator 204 adjusts the pressure of the compressed air created by the compressor 205 to the required air pressure and supplies the pressurized air from the compressor 205 to the ink tank 202.

[0020] As a result, pressurized ink 10 is supplied to the ink inlet 113 of the head 100, and the ink 10 is discharged from the nozzle 102 in accordance with the opening and closing of the valve body 130. Here, the tube 201, ink tank 202, pipe 203, air regulator 204, and compressor 205 are an example of a "pressurization mechanism" and function as a pressurization mechanism 200 for pressurizing and supplying ink 10 to the liquid chamber 114.

[0021] Furthermore, in Figure 2, a portion of the housing 110 of the head 100 (the upper part in Figure 2) is attached to the head holding member 301. The head holding member 301 is equipped with a drive device 302, and by driving the drive device 302, the head holding member 301 is configured to move along the rail member 303 in the directions of arrows A and B.

[0022] As a result, the head 100 attached to the head holding member 301 also moves along the rail member 303 in the directions of arrows A and B. Here, the head holding member 301, the drive unit 302, and the rail member 303 are examples of a "movement mechanism" and function as a head movement mechanism 300 for moving the head 100 relative to the object to which the liquid is discharged. The drive unit 302 and the 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.

[0023] 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 also have the function of controlling the overall operation of the liquid dispensing device, which will be described later, and additional components may be added as needed, in addition to the components shown in Figure 3.

[0024] 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 the pressurization on and off. Furthermore, the control unit 600 transmits a movement signal to the head moving mechanism 300 to move the head 100.

[0025] The drive control unit 500 of the head unit HU generates a drive waveform based on the ink ejection cycle signal received from the control unit 600, and drives the head 100 using the generated drive waveform. The head 100 opens and closes the nozzles 102 in accordance with the drive waveform from the drive control unit 500 and ejects ink.

[0026] 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 supplied to the liquid chamber 114 between a pressurized state and an unpressurized state.

[0027] 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.

[0028] [Head unit operation] Next, the operation of the head unit HU will be explained with reference to Figures 4 to 6.

[0029] Figure 4 is an explanatory diagram showing an example of a head drive waveform. Figure 4(a) shows the liquid ejection waveform used when ejecting ink from the head 100, and Figures 4(b) and 4(c) show the valve body vibration waveforms used when vibrating the valve body 130 of the head 100. Figures 5 and 6 are explanatory diagrams illustrating the operation of the head unit.

[0030] The liquid discharge waveform shown in Figure 4(a) and the valve body vibration waveform shown in Figure 4(b) are generated by the drive control unit 500 and applied from the drive control unit 500 to the piezoelectric element 132. The voltage V3 of the valve body vibration waveform is greater than the voltage V1 of both the liquid discharge waveform and the valve body vibration waveform, and less than the voltage V2 of the liquid discharge waveform. Also, the voltage V4 of the valve body vibration waveform is less than voltage V3 and greater than voltage V1.

[0031] When a voltage according to the liquid ejection waveform (Figure 4(a)) is applied to the piezoelectric element 132 from the drive control unit 500, the valve body 130 is in a position to contact the nozzle plate 101, as shown in Figure 5(a), when voltage V1 is applied to the piezoelectric element 132. In this state, the valve body 130 closes the nozzle 102, so the ink 10 in the liquid chamber 114 is not ejected from the nozzle 102.

[0032] When a voltage V2 is applied to the piezoelectric element 132, as shown in Figure 5(b), the piezoelectric element 132 contracts, causing the needle 131 to move upward in the figure. Along with this movement of the needle 131, the valve body 130 also moves to a position away from the nozzle plate 101, and a gap G is formed between the tip of the valve body 130 and the nozzle 102. The ink 10 in the liquid chamber 114 is supplied under pressure by the pressurization mechanism 200, for example, at a pressure of about 0.1 to 3.0 MPa, and as the gap G is formed, the ink 10 in the liquid chamber 114 is ejected from the nozzle 102 as ink droplets 10'.

[0033] Thus, when a liquid ejection waveform is applied to the piezoelectric element 132, the valve body 130 moves between a position in contact with the nozzle plate 101 and a position away from it (in the direction of arrow C in Figure 5(b)), and the valve body 130 opens and closes the nozzle 102. The valve body 130 is controlled by opening and closing the nozzle 102 so that the ink 10 is ejected from the nozzle 102 (hereinafter, this control will also be referred to as the "first control").

[0034] When voltages V3 and V4, corresponding to the valve body vibration waveform (Figure 4(b)), are alternately applied from the drive control unit 500 to the piezoelectric element 132, the valve body 130 moves via the piezoelectric element 132 and the needle 131 as shown by arrow D in Figure 6. In other words, the valve body 130 moves with a smaller amplitude than when liquid is being discharged, while being separated from the nozzle plate 101. Since the voltages V3 and V4 of the valve body vibration waveform are greater than the voltage V1 of the liquid discharge waveform (Figure 4(a)), when voltage V3 or voltage V4 is applied to the piezoelectric element 132, the valve body 130 is separated from the nozzle plate 101. This movement makes it possible to remove foreign matter adhering to the surface of the valve body 130.

[0035] Furthermore, as shown in Figure 4(b), by making the voltages V3 and V4 smaller than the voltage V2 of the liquid discharge waveform, the valve body 130 can be vibrated with a smaller potential difference than that of the liquid discharge waveform, thereby reducing the heat generation and power consumption of the piezoelectric element 132.

[0036] In other words, the drive control unit 500 vibrates the valve body 130 while it is separated from the nozzle plate 101, and controls it to dislodge any foreign matter adhering to the surface of the valve body 130 (hereinafter, this control will also be referred to as the "second control").

[0037] Note that in the valve body vibration waveform shown in Figure 4(b), voltages V3 and V4 are set to voltages smaller than voltage V2. However, voltages V3 and V4 can be set to any voltage at which the valve body 130 is separated from the nozzle plate 101. For example, as shown in Figure 4(c), voltage V3 of the valve body vibration waveform may be set to the same voltage as voltage V2 of the liquid discharge waveform. By setting voltages V3 and V2 to the same voltage, voltage control by the drive control unit 500 can be simplified.

[0038] As an example other than those mentioned above, if the voltage V3 of the valve body vibration waveform is made greater than the voltage V2 of the liquid discharge waveform, the amplitude of vibration of the valve body 130 can be increased at a position sufficiently far from the nozzle plate 101. This makes it possible to remove foreign matter adhering to the valve body 130 more effectively.

[0039] Furthermore, while Figures 4(b) and 4(c) illustrate a configuration in which voltages V3 and V4 are alternately applied to the piezoelectric element 132 as the valve body vibration waveform, the shape of the waveform is not limited to this. The valve body vibration waveform can be any waveform that vibrates the valve body 130 while it is separated from the nozzle plate 101, and for example, the valve body vibration waveform may be a sinusoidal wave or a triangular wave.

[0040] The drive control unit 500 can selectively execute the first control and the second control described above. For example, in order to remove foreign matter from the surface of the valve body 130 before starting the liquid discharge operation, it is preferable to execute the second control before executing the first control.

[0041] In the above explanation, the piezoelectric element 132 is given as an example having expansion and contraction characteristics that cause it to contract away from the nozzle plate 101 when a voltage is applied, but it is not limited to this. For example, the piezoelectric element 132 may be one that has expansion and contraction characteristics that cause it to extend towards the nozzle plate 101 when a voltage is applied.

[0042] In this case, applying a voltage V2 to the piezoelectric element 132 causes the piezoelectric element 132 to expand, and the valve body 130 closes the nozzle 102. Conversely, applying a voltage V1 to the piezoelectric element 132 causes the piezoelectric element 132 to contract, and the valve body 130 opens the nozzle 102, discharging the pressurized ink 10 supplied to the liquid chamber 114 from the nozzle 102.

[0043] As described above, this embodiment is a head unit HU comprising a head 100 having a nozzle plate 101 on which a nozzle 102 is formed, a liquid chamber 114 for containing ink 10 to be ejected from the nozzle 102, a valve body 130 provided in the liquid chamber 114, a needle 131 connected to the valve body 130, and a piezoelectric element 132 that moves the valve body 130 between a position in contact with the nozzle plate 101 and a position separated from it, and drives the needle 131 so that the valve body 130 opens and closes the nozzle 102, and a drive control unit 500 that controls the driving of the piezoelectric element 132, wherein the drive control unit 500 controls the piezoelectric element 132 to vibrate the valve body 130 when the valve body 130 is separated from the nozzle plate 101.

[0044] Furthermore, as described above, the drive control unit 500 can selectively perform a first control, which moves the valve body 130 between a position in contact with the nozzle plate 101 and a position separated from it to eject ink 10 from the nozzle 102, and a second control, which vibrates the valve body 130 while it is separated from the nozzle plate 101.

[0045] This makes it possible to remove foreign matter (e.g., components or particles in the ink) adhering to the surface of the valve body 130, thereby reducing the decrease in the sealing performance of the nozzle 102 due to the adhesion of foreign matter to the valve body 130.

[0046] [Differentiation] Figure 7 is an explanatory diagram showing a modified example. This modified example differs from the configuration of the above-described embodiment in that it is equipped with a vibration mechanism 400 in the liquid passage leading to the liquid chamber 114.

[0047] The vibration mechanism 400 applies vibration to the ink 10 in the liquid passage, and through the vibrated ink 10, further external vibration is applied to the valve body 130, which is moving (vibrating) in the direction of arrow D. This makes it possible to more effectively remove foreign matter adhering to the surface of the valve body 130.

[0048] [Example of operation in a device that dispenses liquid] Figure 8 is an explanatory diagram showing an example of operation in a device that dispenses liquid.

[0049] As explained in Figure 1, the head unit HU is provided with a head movement mechanism 300 that is installed in the liquid dispensing device, allowing it to move in the left-right direction in the figure.

[0050] When performing the second control, which involves vibrating the valve body 130 in the direction of arrow D using the valve body vibration waveform, the drive control unit 500 turns off the pressurization of the ink 10 by the pressurization mechanism 200, as shown in Figure 8(a). That is, in the first control, when the valve body 130 is moved between a position in contact with the nozzle plate 101 and a position away from it to eject the ink 10 from the nozzle 102, the drive control unit 500 pressurizes the ink 10 using the pressurization mechanism 200. In contrast, in the second control, the pressurization of the ink 10 by the pressurization mechanism 200 is stopped.

[0051] This ensures that when ink 10 is ejected towards the ejection area of ​​the liquid ejection target object 1000, pressure is applied to the ink 10, ensuring that the ink 10 is reliably ejected from the nozzle 102. Furthermore, when the valve body 130 is vibrated to remove foreign matter adhering to the valve body 130, it prevents ink 10 from being unintentionally ejected towards the liquid ejection target object 1000. In addition, ink consumption can be reduced.

[0052] In the case of Figure 8(a), since the nozzle 102 is in an open state, even if the ink 10 is not pressurized, there is a possibility that the ink 10 may be inadvertently ejected due to pressure fluctuations within the device or electrical noise within the drive control unit 500.

[0053] Preferably, prior to the second control, the drive control unit 500 stops pressurizing the ink 10 and moves the nozzle 102 to a position (non-discharge area) that does not face the discharge area of ​​the liquid discharge target 1000 using the head moving mechanism 300. Then, with the head 100 moved to the non-discharge area, the valve body 130 is separated from the nozzle plate 101 and vibrated. This makes it possible to more reliably prevent unintentional ink discharge in the discharge area.

[0054] Next, a second embodiment of the present invention will be described with reference to Figure 9. Figure 9 is an explanatory diagram showing a second embodiment of the head unit according to the present invention. Figure 9(a) is a cross-sectional view showing the nozzle in a closed state, and Figure 9(b) is a cross-sectional view showing the nozzle in an open state.

[0055] The second embodiment differs from the above-described embodiment in that it includes a reverse spring mechanism 134 as an example of a transmission mechanism between the needle 131 and the piezoelectric element 132. In the second embodiment, the piezoelectric element 132 used has the characteristic of expanding and contracting toward the nozzle plate 101 when a voltage is applied.

[0056] The reverse spring mechanism 134 is an elastic member formed by molding rubber, soft resin, or a thin metal plate that can be appropriately deformed. The reverse spring mechanism 134 comprises a deformable portion 134a, a fixed portion 134b, a guide portion 134c, and a bent edge 134d.

[0057] The deformed portion 134a has a substantially trapezoidal cross-section and is formed so as to abut against the base end surface of the needle 131 (the upper end surface of the needle 131 in Figure 9(a)).

[0058] The fixing portion 134b is fixed to the deformable portion 134a and to the inner wall surface of the housing 110.

[0059] The guide section 134c connects the fixing section 134b and the piezoelectric element 132.

[0060] The bent side 134d connects the longer side (corresponding to the bottom base of the trapezoid) of the trapezoidal deformation part 134a to the fixing part 134b.

[0061] In the reverse spring mechanism 134 having the structure described above, when a predetermined voltage is applied to the piezoelectric element 132 and the piezoelectric element 132 expands, the guide portion 134c is pushed toward the nozzle 102 (in the direction of arrow a in Figure 9(b)).

[0062] This pushing force pulls the deformable part 134a away from the nozzle 102 (in the direction of arrow b in Figure 9(b)). In other words, the reverse spring mechanism 134 converts the stretching force of the piezoelectric element 132 into a force that pulls in the needle 131, and then transmits it to the needle 131.

[0063] In the head 100 according to the second embodiment, applying a voltage to the piezoelectric element 132 causes the piezoelectric element 132 to extend, which in turn causes the valve body 130 to open the nozzle 102, and a droplet 10' is discharged from the nozzle 102.

[0064] As described above, the second embodiment includes a reverse spring mechanism 134 between the needle 131 and the piezoelectric element 132 that converts the stretching force of the piezoelectric element 132 into a force that pulls the needle 131 in, that is, a force opposite to the stretching force of the piezoelectric element 132, and then transmits it to the needle 131.

[0065] In the second embodiment as well, by implementing the second control described above, it is possible to remove foreign matter adhering to the surface of the valve body 130 from the valve body 130, thereby reducing the decrease in the sealing performance of the nozzle 102 due to the adhesion of foreign matter to the valve body 130.

[0066] [Application Examples] Next, we will explain application examples with reference to Figure 10. Figure 10 is an explanatory diagram showing application examples.

[0067] As shown in Figure 10, the head module 700 is equipped with multiple heads 100 (eight in the example of Figure 10) in a housing 710.

[0068] The housing 710 has a supply port 711 for supplying ink 10 into the housing 710, a supply passage 712 connecting the supply port 711 and the injection port 713, and an outlet port 715 provided on the opposite side of the injection port 713, with the liquid chamber 714 in between. The housing 710 also has a recovery port 717 for recovering the ink 10 inside the housing 710, and a recovery passage 716 connecting the recovery port 717 and the outlet port 715.

[0069] The basic configuration of the multiple heads 100 is the same as that described with reference to Figures 1 to 6, and in Figure 10, the corresponding elements are denoted by symbols in the 700s.

[0070] In this application example, eight heads 100 are provided such that each nozzle 702 is arranged at approximately equal intervals in one direction (left-right direction in Figure 10). Each head 100 extends vertically so as to eject ink 10 downwards from the nozzle 702 at the bottom of the figure.

[0071] The liquid chamber 714 of each of the eight heads 100 is provided to penetrate the arrangement of the eight heads 100, allowing the ink 10 to flow from one side (left side in Figure 10) to the other side (right side in Figure 10). In other words, the configuration differs from the above-described embodiment in that each head 100 has an outlet 715 on the opposite side of the injection port 713.

[0072] [Examples of application] Next, with reference to Figures 11 and 12, an example of the application of the head module 700 described in Figure 10 will be explained. Figure 11 is an overall perspective view showing an example of a carriage, and Figure 12 is an overall perspective view showing an example of a liquid dispensing device equipped with the carriage of Figure 11. Note that Figure 11 shows the carriage 801 mounted on the liquid dispensing device 800 shown in Figure 12, viewed from the liquid dispensing target object 1000 side.

[0073] The carriage 801 includes a head holder 80. The carriage 801 is also movable along the Z-axis rail 804 in the Z-direction (positive and negative) direction by power from the first Z-direction drive unit 807, which will be described later.

[0074] The head holder 80 is movable in the Z direction (positive and negative) relative to the carriage 801 by power from a second Z-direction drive unit 808, which will be described later. The head holder 80 also includes a head fixing plate 80a for attaching the head module 700.

[0075] In this application example, a configuration is shown in which six head modules 700, as described in Figure 10, are attached to a head fixing plate 80a, and the six head modules 700 are arranged in a stacked configuration.

[0076] Each head module 700 is equipped with multiple nozzles 702. The type and number of ink colors used in each head module 700 may be different colors for each head module 700, or they may all be the same color. For example, if the liquid ejecting device 800 is a single-color coating device, the ink used in each head module 700 may be the same color. Also, the number of head modules is not limited to six. There may be more than six, or fewer than six.

[0077] As shown in the figure, the head module 700 is fixed to the head fixing plate 80a with a nozzle row (a row of eight nozzles 702) intersecting the horizontal plane (XZ plane) and with the arrangement direction of the multiple nozzles 702 tilted with respect to the X axis. In this state, the nozzles 702 eject ink in a direction intersecting the direction of gravity (positive Z direction).

[0078] The printing device 800, shown in Figure 12 as an example of a liquid dispensing device, is installed facing the object 1000 from which the liquid is to be dispensed. The printing device 800 includes an X-axis rail 802, a Y-axis rail 803 that intersects with the X-axis rail 802, and a Z-axis rail 804 that intersects with the X-axis rail 802 and the Y-axis rail 803.

[0079] The Y-axis rail 803 holds the X-axis rail 802 so that the X-axis rail 802 can move in the Y direction (positive and negative). The X-axis rail 802 also holds the Z-axis rail 804 so that the Z-axis rail 804 can move in the X direction (positive and negative). The Z-axis rail 804 holds the carriage 801 so that the carriage 801 can move in the Z direction (positive and negative).

[0080] The printing apparatus 800 includes a first Z-direction drive unit 807 that moves the carriage 801 in the Z-direction along the Z-axis rail 804, and an X-direction drive unit 805 that moves the Z-axis rail 804 in the X-direction along the X-axis rail 802. The printing apparatus 800 also includes a Y-direction drive unit 806 that moves the X-axis rail 802 in the Y-direction along the Y-axis rail 803. Furthermore, the printing apparatus 800 includes a second Z-direction drive unit 808 that moves the head holder 80 in the Z-direction relative to the carriage 801.

[0081] The printing device 800 prints on the liquid ejection target object 1000 by ejecting ink from the head module 700 (see Figure 11) installed on the head holder 80 while moving the carriage 801 in the X, Y, and Z directions. Note that the movement of the carriage 801 and the head holder 80 in the Z direction does not necessarily have to be parallel to the Z direction; it may be oblique movement as long as it includes at least a component in the Z direction.

[0082] Furthermore, although the surface shape of the liquid discharge target object 1000 is shown as a flat surface, it may also be a nearly vertical surface, such as the body of a car or truck, or the fuselage of an aircraft, a surface with a large radius of curvature, or a surface with some irregularities.

[0083] In this invention, the liquid may be a solution, suspension, emulsion, or the like containing a solvent such as water or an organic solvent, a coloring agent such as a dye or pigment, a polymerizable compound, a resin, a functionalizing material such as a surfactant, a biocompatible material such as DNA, amino acids or proteins, calcium, or an edible material such as a natural pigment.

[0084] These can be used, for example, in inkjet inks, coatings, surface treatment liquids, components for electronic elements and light-emitting elements, liquids for forming electronic circuit resist patterns, and 3D fabrication materials.

[0085] Furthermore, the liquid dispensing device according to the present invention is not limited to the form of the printing apparatus described above. For example, it may be a configuration in which the head unit (or head) of the present invention is attached to the tip of a robotic arm of a multi-joint robot that has multiple joints that allow for free movement like a human arm.

[0086] Furthermore, the device for dispensing liquid is not limited to one in which the head moves relative to the object from which the liquid is dispensed. It is sufficient that the head and the object from which the liquid is dispensed can move relative to each other, and the device may also be configured to move the object from which the liquid is dispensed relative to the head.

[0087] The above is merely an example, and the present invention provides specific effects in each of the following embodiments.

[0088] [First aspect] The first embodiment is a head unit (e.g., head unit HU) comprising a liquid discharge head (e.g., head 100) having a nozzle plate on which a nozzle is formed, a liquid chamber for containing liquid to be discharged from the nozzle, a valve body provided in the liquid chamber, a valve body connecting member (e.g., needle 131) connected to the valve body, and a drive mechanism (e.g., piezoelectric element 132) that moves the valve body between a position in contact with the nozzle plate and a position separated from it, and drives the valve body connecting member so that the valve body opens and closes the nozzle, and a drive control unit (e.g., drive control unit 500) that controls the driving of the drive mechanism, wherein the drive control unit controls the drive mechanism so that the valve body vibrates when the valve body is separated from the nozzle plate.

[0089] [Second aspect] In the second embodiment, the drive control unit (for example, the drive control unit 500) is capable of selectively performing a first control, which moves the valve body between a position in contact with the nozzle plate and a position separated from it to discharge the liquid from the nozzle, and a second control, which vibrates the valve body while it is separated from the nozzle plate.

[0090] According to the first and second embodiments, it becomes possible to remove foreign matter adhering to the surface of the valve body from the valve body, thereby reducing the decrease in nozzle sealing performance due to the adhesion of foreign matter to the valve body.

[0091] [Third aspect] A third embodiment is provided in the first or second embodiment with an excitation mechanism (for example, an excitation mechanism 400) that provides vibration to the liquid in the liquid passage leading to the liquid chamber, thereby causing the valve body to vibrate through the vibrated liquid.

[0092] According to the third embodiment, foreign matter adhering to the surface of the valve body can be removed more effectively.

[0093] [Fourth aspect] The fourth embodiment is a liquid dispensing device (e.g., a printing device 800) equipped with a head unit as described in any of the first to third embodiments.

[0094] [Fifth aspect] A fifth embodiment, in the fourth embodiment, includes a pressurizing mechanism (e.g., pressurizing mechanism 200) for pressurizing the liquid in the liquid chamber, and the drive control unit (e.g., drive control unit 500) moves the valve body between a position in contact with the nozzle plate and a position separated from it when the pressurizing mechanism is pressurizing the liquid, thereby discharging the liquid from the nozzle, and vibrates the valve body separated from the nozzle plate when the pressurizing mechanism is not pressurizing the liquid.

[0095] According to the fourth and fifth embodiments, when discharging liquid towards the discharge area of ​​a liquid discharge target, the liquid can be reliably discharged from the nozzle by applying pressure to the liquid. In addition, when vibrating the valve body to dislodge foreign matter adhering to the valve body, it is possible to prevent the liquid from being unintentionally discharged towards the liquid discharge target.

[0096] [Sixth aspect] The sixth embodiment is a fifth embodiment, further comprising a moving mechanism (e.g., head moving mechanism 300) for moving the liquid discharge head (e.g., head 100), wherein the drive control unit (e.g., drive control unit 500) moves the valve body between a position in contact with the nozzle plate and a position separated from it while the pressurizing mechanism (e.g., pressurizing mechanism 200) is pressurizing the liquid, thereby discharging the liquid from the nozzle to the discharge area of ​​the liquid discharge target, and while the pressurizing mechanism is not pressurizing the liquid and the liquid discharge head has been moved by the moving mechanism to a position where the nozzle does not face the discharge area, the valve body is separated from the nozzle plate and vibrated.

[0097] According to the sixth embodiment, unintentional ink ejection in the ejection area of ​​the liquid ejection target can be prevented more reliably. [Explanation of symbols]

[0098] 100 liquid dispensing heads 101 Nozzle Plate 102 Nozzles 130 valve body 131 Needle (an example of a valve body connecting member) 132 Piezoelectric element (an example of a driving mechanism) 500 Drive Control Unit 800 Printing equipment (an example of a device that dispenses liquid) 1000 Liquid discharge target objects HU Head Unit

Claims

1. A liquid dispensing device having a head unit comprising: a nozzle plate on which a nozzle is formed; a liquid chamber for containing liquid to be discharged from the nozzle; a valve body provided in the liquid chamber; a valve body connecting member connected to the valve body; and a drive mechanism for moving the valve body between a position in contact with the nozzle plate and a position separated therefrom, thereby driving the valve body connecting member so that the valve body opens and closes the nozzle; and a drive control unit for controlling the driving of the drive mechanism, The chamber is equipped with a pressurizing mechanism for pressurizing the liquid inside the chamber. The drive control unit, While the pressurizing mechanism is pressurizing the liquid, the valve body is moved between a position in contact with the nozzle plate and a position separated from it, thereby discharging the liquid from the nozzle. A liquid dispensing device that controls the drive mechanism to vibrate the valve body by separating it from the nozzle plate when the pressurizing mechanism is not pressurizing the liquid.

2. The device for discharging liquid according to claim 1, wherein the drive control unit is capable of selectively performing a first control, which moves the valve body between a position in contact with the nozzle plate and a position separated from it to discharge the liquid from the nozzle, and a second control, which vibrates the valve body while it is separated from the nozzle plate.

3. The device for discharging liquid according to claim 2, wherein the drive control unit controls the drive mechanism such that the amplitude of the vibration of the valve body in the second control is smaller than the distance the valve body moves between the position in which it contacts the nozzle plate and the position in which it separates from the nozzle plate in the first control.

4. The device for discharging liquid according to claim 2, wherein the drive control unit executes the first control following the second control.

5. A liquid dispensing device according to claim 1 or 2, comprising a vibration mechanism in a liquid passage leading to the liquid chamber, which applies vibration to the liquid in the liquid passage and causes the valve body to vibrate through the vibrated liquid.

6. The invention relating to Claim 1, comprising a moving mechanism for moving the liquid discharge head, The drive control unit, While the pressurizing mechanism is pressurizing the liquid, the valve body is moved between a position in contact with the nozzle plate and a position separated from it, thereby discharging the liquid from the nozzle into the discharge area of ​​the liquid to be discharged. A liquid dispensing device that, with the pressurizing mechanism not pressurizing the liquid and the liquid dispensing head moved by the moving mechanism to a position where the nozzle does not face the dispensing area, causes the valve body to vibrate while being separated from the nozzle plate.

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