Coating device

Abstract

To provide a coating device that can control coating of viscous fluid at high speed.SOLUTION: A coating device 1A comprises a discharge part 2 and a rotating body 10A. The discharge part 2 stores viscous fluid 9. The rotating body 10A is stored in the discharge part 2 and has a shaft 11 and a protrusion 12A. The shaft 11 can rotate with a central shaft C as a rotation center. The protrusion 12A protrudes in a radial direction of the shaft 11. The coating device 1A performs coating of the viscous fluid 9 through cooperation between rotation of the rotating body 10A and application of a voltage by a pulse power supply 21.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coating device. [Background technology]

[0002] A method for forming an electrode catalyst layer is known in which a catalyst ink is applied by electrospraying by applying a voltage between a conductive nozzle and a metal substrate. Patent Document 1 describes an electrode catalyst forming device that includes an ink reservoir container that contains the catalyst ink. The conductive nozzle is provided on the underside of the ink reservoir container and communicates with the ink reservoir container. A pressure regulator is connected to the ink reservoir container. By creating a negative pressure inside the ink reservoir container with the pressure regulator, the catalyst ink is prevented from dripping due to its own weight when low-viscosity catalyst ink is not being applied. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-103179 Summary of the Invention [Problem to be solved by the invention]

[0004] Highly viscous catalyst inks are sometimes applied by electrospray. Because such inks are difficult to eject from conductive nozzles, a possible solution is to use a pressure regulator to create positive pressure inside the ink reservoir. However, because it takes time to change the pressure in the ink reservoir, it is difficult to control the application of the catalyst ink at high speed using the above-mentioned forming device.

[0005] An object of the present invention is to provide a coating device that can control the coating of a viscous fluid at high speed. [Means for solving the problem]

[0006] A coating device according to one aspect of the present invention is characterized by comprising: a housing that contains a viscous fluid; an ejection unit having a nozzle; an opposing electrode facing the nozzle; a power source that applies a voltage between the opposing electrode and the ejection unit; a rotating body that has a rotatable shaft and a protrusion that protrudes from the shaft in a direction that intersects the axis, the rotating body being housed in the ejection unit and rotating to push the viscous fluid from the nozzle in an ejection direction toward the opposing electrode, and that ejects the viscous fluid from the nozzle in cooperation with the power source that applies the voltage.

[0007] The coating device according to this aspect discharges a viscous fluid by applying a voltage from a power source and rotating a rotor. The coating device extrudes the viscous fluid by rotating the rotor without changing the pressure inside the discharge section, so the coating of the viscous fluid can be controlled at high speed compared to when discharging by changing the pressure inside the discharge section. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the configuration of a coating device 1A. [Figure 2] 2 is a cross-sectional view of the housing 3 cut along a plane perpendicular to the central axis C. FIG. [Figure 3] 10 is a diagram showing the relationship between the vertical flow velocity of the viscous fluid 9 and the radial distance from the central axis C when the rotor 10A rotates. FIG. [Figure 4] FIG. 2 is a block diagram showing the electrical configuration of the coating device 1A. [Figure 5] 10 is a diagram showing synchronization between the rotation of a rotating body 10A and a pulse voltage. FIG. [Figure 6] 10 is a flowchart of a main process. [Figure 7] FIG. 10 is a diagram showing the configuration of a coating device 1B of a modified example. [Figure 8] 10A and 10B are diagrams showing a first modified example of synchronization between the rotation of a rotor 10A and a pulse voltage. [Figure 9] 10A and 10B are diagrams showing a second modified example of synchronization between the rotation of the rotor 10A and the pulse voltage. [Figure 10]10 is a diagram showing a third modified example of synchronization between the rotation of a rotor 10A and a pulse voltage. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings are used to explain technical features that can be adopted by the present invention. In other words, the configurations and the like shown in the drawings are merely illustrative examples and are not intended to limit the present invention.

[0010] <Configuration of coating device 1A> The configuration of the coating apparatus 1A will be described with reference to Figures 1 and 2. Hereinafter, the left, right, front side of the paper, rear side of the paper, upper side, and lower side of Figures 1 and 2 will be referred to as the left, right, front, rear, upper side, and lower side of the coating apparatus 1A, respectively. The left-right direction will also be referred to as the X-axis direction. The front-rear direction will also be referred to as the Y-axis direction. Note that in this embodiment, the up-down direction is used for convenience of explanation and is not limited to the vertical direction.

[0011] The coating device 1A shown in FIGS. 1 and 2 coats a medium 19A with a viscous fluid 9. In this embodiment, the viscous fluid 9 is selected from a variety of fluids, including ink and hot-melt materials. When the viscous fluid 9 is ink, the coating device 1A prints the medium 19A as a form of coating the medium 19A. Hot-melt materials have thermoplastic properties and melt when heated. The viscosity μ of ink and hot-melt materials is approximately 10 to 100 (Pa·s). The medium 19A is, for example, fabric, paper, or plastic film. The medium 19A may be conductive or insulating.

[0012] The coating device 1A has a discharge unit 2, a rotating body 10A, a rotary motor 15, a table 17, a counter electrode 18, a pulse power supply 21, and a heater power supply 22. The discharge unit 2 has a housing 3, a nozzle 5, and a lid 7. The housing 3 is cylindrical with a central axis extending in the vertical direction. The housing 3 is conductive. The housing 3 has an opening 4 that opens upward. The opening 4 has a circular shape centered on the central axis C in a plan view (see Figure 2). The housing 3 stores a viscous fluid 9 in the opening 4.

[0013] The nozzle 5 is provided at the lower end of the housing 3 and is cylindrical with a central axis extending in the vertical direction. The nozzle 5 is conductive. The radial length of the nozzle 5 is shorter than the radial length of the housing 3. The central axis of the nozzle 5 overlaps with the central axis of the housing 3. Hereinafter, the central axis common to the housing 3 and the nozzle 5 will be referred to as the central axis C. The nozzle 5 has an opening 6 that opens the nozzle 5 in the vertical direction and communicates with the opening 4. The opening 6 has a circular shape centered on the central axis C in a plan view. Hereinafter, the lower end of the opening 6 will be referred to as the discharge outlet.

[0014] The lid 7 is provided at the upper end of the housing 3 and is disk-shaped with a central axis extending in the vertical direction. The lid 7 is insulating. The radial length of the lid 7 is shorter than the radial length of the housing 3. The central axis of the lid 7 overlaps with the central axis C. That is, the lid 7, housing 3, and nozzle 5 in the discharge part 2 are aligned on the central axis C. The lid 7 is provided with an opening 8 that opens the lid 7 in the vertical direction and communicates with the opening 4. The opening 8 is circular in shape with the central axis C as its center in a plan view.

[0015] Rotating body 10A has a shaft 11, an electric heater 13 (see Figure 4), and protrusions 12A. Shaft 11 is cylindrical with a central axis extending in the vertical direction. Shaft 11 is conductive. The radial length of shaft 11 is approximately the same as the radial length of opening 8. Shaft 11 overlaps with central axis C. The lower end of shaft 11 is located between the vertical center of housing 3 and the lower end of housing 3. The lower end of shaft 11 is the lower end of rotating body 10A.

[0016] The upper end of shaft 11 is located above lid 7. That is, shaft 11 passes through opening 8 and protrudes upward from discharge portion 2. Shaft 11 is rotatably supported by lid 7. The portion of shaft 11 that is housed in housing 3 is referred to as housing portion 110.

[0017] Although not shown, an opening is provided in the shaft 11 that opens the shaft 11 upward. The opening extends from near the lower end of the shaft 11 to the upper end of the shaft 11. An electric heater 13 (see FIG. 4) is housed in the shaft 11. The electric heater 13 is, for example, a resistance heating element that generates heat when electricity is applied. The electric heater 13 may be a metal heating element such as tungsten, or a non-metal heating element such as silicon carbide.

[0018] Protrusion 12A is plate-shaped and protrudes from the side surface of shaft 11 in the radial direction of shaft 11. More specifically, protrusion 12A extends spirally around shaft 11 in housing portion 110 of shaft 11. The lower end of protrusion 12A is located near the lower end of housing portion 110. The upper end of protrusion 12A is located near the upper end of housing portion 110. Protrusion 12A has a circular shape centered on the center of shaft 11 in a plan view. When shaft 11 rotates, protrusion 12A rotates integrally with shaft 11.

[0019] 2, the central axis of rotating body 10A coincides with the central axis of shaft 11 in the front-rear and left-right directions. That is, the rotation center of rotating body 10A coincides with central axis C. Therefore, the center of rotating body 10A coincides with the center of housing 3 in the front-rear and left-right directions.

[0020] As shown in FIG. 1, a coupling 14 is provided at the upper end of the shaft 11. The coupling 14 is disk-shaped and has a central axis extending in the vertical direction. The coupling 14 has insulating properties. The central axis of the coupling 14 overlaps with the central axis C. The opening of the shaft 11 is covered by the coupling 14.

[0021] The rotary motor 51 is provided above the coupling 14. The rotary shaft of the rotary motor 51 is connected to the coupling 14. The rotary motor 51 rotates the rotating body 10A via the coupling 14. In this embodiment, the rotation speed of the rotary motor 51 is W1 ( / s) (see FIG. 5).

[0022] When the rotor 10A rotates in one direction of rotation of the rotor 10A, the protrusions 12A push the viscous fluid 9 contained in the housing 3 downward. When the rotor 10A rotates in the other direction of rotation of the rotor 10A, the protrusions 12A push the viscous fluid 9 contained in the housing 3 upward. The rotation of the rotor 10A when pushing the viscous fluid 9 downward is called forward rotation. The rotation of the rotor 10A when pushing the viscous fluid 9 upward is called reverse rotation. Furthermore, when the rotor 10A rotates forward or reverse, the protrusions 12A agitate the viscous fluid 9 in the housing 3. In other words, the rotor 10A is a mechanism that moves the viscous fluid 9 up and down while agitating it by rotating about the central axis C as the center of rotation.

[0023] FIG. 3 shows the downward flow velocity U of the viscous fluid 9 between the lower end of the shaft 11 and the lower end of the housing 3 when the rotor 10A rotates forward. The flow velocity U is greatest on the central axis C and is smallest at a distance R from the central axis C. The distance R is the distance from the central axis C of the housing 3 to the open end of the opening 4. Because the center of the rotor 10A coincides with the center of the housing 3, the flow velocity U at a certain position in the X-axis direction is the same as the flow velocity U at a position symmetrical to the central axis C. Although not shown, the flow velocity U of the viscous fluid 9 in the Y-axis direction is also symmetrical about the central axis C. Similarly, the flow velocity U of the viscous fluid 9 is also symmetrical about the central axis C between the lower end of the shaft 11 and the upper end of the viscous fluid 9 contained in the housing 3.

[0024] As shown in FIG. 1, the table 17 is provided below the nozzle 5 at a distance and has a plate shape that extends perpendicular to the up-down direction. The table 17 is insulating. A movement mechanism (not shown) is provided on the table 17. The movement mechanism has an X-axis motor 52 (see FIG. 4) and a Y-axis motor 53 (see FIG. 4). The X-axis motor 52 moves the table 17 in the left-right direction. The Y-axis motor 53 moves the table 17 in the front-back direction. In other words, the table 17 moves relative to the nozzle 5 in the left-right and front-back directions by the movement mechanism.

[0025] The counter electrode 18 is provided on the upper surface of the table 17 and has a plate shape that extends perpendicularly in the vertical direction. The counter electrode 18 is conductive. The counter electrode 18 supports the medium 19A from below. The counter electrode 18 and the nozzle 5 face each other in the vertical direction. When the table 17 is moved by the movement mechanism, the counter electrode 18 and the medium 19A move integrally with the table 17.

[0026] The pulsed power supply 21 applies a pulsed voltage at a predetermined cycle (see FIG. 5). The positive electrode of the pulsed power supply 21 is connected to the nozzle 5 of the discharge unit 2. The negative electrode of the pulsed power supply 21 is connected to the counter electrode 18 and a ground unit 29. The negative electrode of the pulsed power supply 21 is grounded by the ground unit 29. When the pulsed voltage is on, a potential difference of V1 (V) is generated between the nozzle 5 and the counter electrode 18. In this embodiment, the magnitude of the potential difference V1 is 1 to 10 (kV). When the pulsed voltage is off, no potential difference is generated between the nozzle 5 and the counter electrode 18 (0 (V), see FIG. 5).

[0027] The heater power supply 22 applies a DC voltage. The positive and negative electrodes of the heater power supply 22 are connected to the electric heater 13, which is a resistance heating element. When the heater power supply 22 applies a DC voltage to the electric heater 13, the electric heater 13 generates heat, and the rotating body 10A is heated. In this embodiment, when the power supply of the coating device 1A is on, the heater power supply 22 applies a DC voltage to heat the rotating body 10A. The viscous fluid 9 is heated via the rotating body 10A, and the viscosity μ decreases. Furthermore, when the viscous fluid 9 is a hot melt material, the viscous fluid 9 is heated and melts.

[0028] <Electrical configuration of coating device 1A> The electrical configuration of the coating device 1A will be described with reference to Figure 4. The coating device 1A has a CPU 31, ROM 32, RAM 33, a storage device 34, drive circuits 41 to 43, power supply circuits 44, 45, an input unit 35, and an output unit 36. The CPU 31 controls the coating device 1A. The ROM 32 stores the relationship between the type of viscous fluid 9 and the viscosity μ, as well as various setting information. The RAM 33 temporarily stores various information. The storage device 34 is non-volatile and stores a control program for executing the main processing (see Figure 6) described below.

[0029] The CPU 31 inputs and outputs various signals to and from the ROM 32, RAM 33, storage device 34, drive circuits 41 to 43, power supply circuits 44 and 45, input unit 35, and output unit 36. The input unit 35 accepts input of various information, instructions, etc. from the user and outputs them to the CPU 31. The input unit 35 is, for example, a keyboard that accepts input in response to user operations. The output unit 36 ​​outputs various information based on instructions from the CPU 31. The output unit 36 ​​is, for example, a liquid crystal display that displays a screen showing various information.

[0030] Drive circuit 41 is connected to rotary motor 51. Drive circuit 42 is connected to X-axis motor 52. Drive circuit 43 is connected to Y-axis motor 53. Rotary motor 51, X-axis motor 52, and Y-axis motor 53 are, for example, stepping motors. Drive circuits 41, 42, and 43 control the driving of rotary motor 51, X-axis motor 52, and Y-axis motor 53 in accordance with instructions input from CPU 31. Power supply circuit 44 is connected to pulse power supply 21. Power supply circuit 45 is connected to heater power supply 22. Power supply circuits 44 and 45 control the voltages applied by pulse power supply 21 and heater power supply 22 in accordance with instructions input from CPU 31.

[0031] <Coating of viscous fluid 9> 1 and 5, the coating of a viscous fluid 9 by the coating device 1A will be described. The coating device 1A changes the coating method depending on the viscosity μ of the viscous fluid 9. First, a case will be described in which the viscosity μ of the viscous fluid 9 is smaller than a predetermined threshold μT (μ<μT), that is, the viscous fluid 9 is used for coating. In this case, the coating device 1A coats the viscous fluid 9 using so-called Coulomb force.

[0032] When the pulse power supply 21 turns on the pulse voltage, the nozzle 5 is positively charged and the counter electrode 18 is negatively charged. A potential difference V1 is generated between the nozzle 5 and the counter electrode 18. The viscous fluid 9 is drawn downward from the nozzle 5 toward the counter electrode 18 due to Coulomb force. At this time, due to the balance between the Coulomb force drawing the viscous fluid 9 and the surface tension of the viscous fluid 9, droplets 90 of the viscous fluid 9 extend into a substantially conical shape below the nozzle 5. The resultant force of the Coulomb force drawing the viscous fluid 9 and the surface tension of the viscous fluid 9 exceeds the surface tension of the viscous fluid 9. At this time, the droplets 90 of the viscous fluid 9 are pulled away from the nozzle 5 and ejected downward toward the counter electrode 18. The ejected viscous fluid 9 coats the medium 19A supported by the counter electrode 18.

[0033] The viscosity μ of the viscous fluid 9 is equal to or greater than a threshold μT (μ≧μT), and a case where a viscous fluid 9 with a high viscosity μ will be described. In this embodiment, when the viscous fluid 9 is a hot melt material, the viscosity μ is equal to or greater than a threshold μT. When the viscosity μ of the viscous fluid 9 is high, the viscous resistance increases, and the viscous fluid 9 cannot be drawn out of the nozzle 5 by Coulomb force alone. Therefore, in the coating device 1A, the viscous fluid 9 is coated by applying a voltage from the pulse power supply 21 and pushing out the viscous fluid 9 by rotating the rotor 10A.

[0034] As shown in Figure 5, when the rotary motor 51 drives the rotor 10A to rotate in the forward direction at a rotational speed W1, the viscous fluid 9 is pushed downward from the outlet of the nozzle 5. Due to the balance between the force of the rotor 10A pushing out the viscous fluid 9 and the surface tension of the viscous fluid 9, a droplet 90 of the viscous fluid 9 extends in a substantially conical shape below the nozzle 5. The vertical length from the nozzle 5 to the bottom end of the droplet 90 of the viscous fluid 9 is L (mm) (see Figure 1). Due to the rotation of the rotor 10A, the length L of the droplet 90 of the viscous fluid 9 extends to a length L1.

[0035] When the length L of the droplets 90 of the viscous fluid 9 has extended to a length L1, the pulse power supply 21 turns on the pulse voltage. The droplets 90 of the viscous fluid 9 are pulled away from the nozzle 5 by Coulomb force and ejected toward the counter electrode 18. The ejection direction D is downward. The ejected viscous fluid 9 coats the medium 19A supported by the counter electrode 18. In this way, the coating device 1A coats the viscous fluid 9 through cooperation between the rotation of the rotating body 10A and the application of voltage by the pulse power supply 21.

[0036] As shown in FIG. 5, the CPU 31 of the coating apparatus 1A controls the drive circuit 41 and power supply circuit 44 to rotate the rotating body 10A forward at a rotational speed W1 for a time t1 (s) and turn off the pulse voltage from the pulse power supply 21. The CPU 31 then stops the rotation of the rotating body 10A for a time t1 (s) and turns on the pulse voltage from the pulse power supply 21. The CPU 31 repeatedly controls the forward and reverse rotation of the rotating body 10A and turns off and on the pulse voltage from the pulse power supply 21. In this way, the coating apparatus 1A synchronizes the extension of the droplets 90 of the viscous fluid 9 caused by the rotation of the rotating body 10A and the peeling of the viscous fluid 9 caused by the application of the pulse voltage from the pulse power supply 21 in a period T1 (s) (see FIG. 5). The period T1 is twice the time t1 (T1 = 2 × t1). In other words, the pulse voltage of pulse power supply 21 has a period T1, and CPU 31 synchronizes the rotation of rotor 10A with period T1 of the pulse voltage.

[0037] When the coating device 1A is not coating the viscous fluid 9, the rotary motor 51 is driven to rotate the rotor 10A in the reverse direction at a rotation speed W1. The viscous fluid 9 is pushed upward in the housing 3. This prevents the viscous fluid 9 from dripping from the nozzle 5 when the coating device 1A is not coating the viscous fluid 9.

[0038] <Main processing> The main processing executed by the CPU 31 will be described with reference to FIG. 6. In the main processing, the medium 19A is coated with the viscous fluid 9. The user inputs an instruction to execute the main processing using the input unit 35. The CPU 31 reads out an initial processing program from the storage device 34. This causes the CPU 31 to start the main processing. Before the main processing starts, the user inputs the type of viscous fluid 9 using the input unit 35. The input type of viscous fluid 9 is stored in the RAM 33. The rotating body 10A is rotated in the reverse direction by the drive of the rotary motor 51, and the viscous fluid 9 is pushed upward.

[0039] When the main process starts, the CPU 31 stops driving the rotary motor 51 and stops the reverse rotation of the rotating body 10A (S1). The CPU 31 acquires the viscosity μ of the medium 19A from the ROM 32 based on the type of the medium 19A stored in the RAM 33 (S2). The CPU 31 determines whether the viscosity μ of the medium 19A acquired in S2 is equal to or greater than the threshold μT (S3).

[0040] If the CPU 31 determines that the viscosity μ of the medium 19A is not equal to or greater than the threshold μT (S3: NO), the CPU 31 starts applying a pulse voltage from the pulse power supply 21 (S4), which starts coating the viscous fluid 9 onto the medium 19A. The CPU 31 then proceeds to S7.

[0041] When the CPU 31 determines that the viscosity μ of the medium 19A is equal to or greater than the threshold μT (S3: YES), it drives the rotary motor 51 to start forward rotation at a period T1 (S5). The viscous fluid 9 is pushed downward toward the outlet of the nozzle 5. The CPU 31 starts applying a pulse voltage at a period T1 using the pulse power supply 21 (S6). Droplets 90 of the viscous fluid 9 extending from the outlet of the nozzle 5 are torn off from the nozzle 5, and the viscous fluid 9 is ejected. This starts the application of the viscous fluid 9 to the medium 19A. The rotation period of the rotary motor 51 and the period of the pulse voltage are synchronized (see FIG. 5). The CPU 31 proceeds to S7.

[0042] The CPU 31 determines whether or not application of the viscous fluid 9 to the medium 19A has been completed (S7). If the CPU 31 determines that application of the viscous fluid 9 has not been completed (S7: NO), the process returns to S7. If the CPU 31 determines that application of the viscous fluid 9 has been completed (S7: YES), the CPU 31 stops the forward rotation of the rotating body 10A by the rotary motor 51 and the application of the pulse voltage by the pulse power supply 21 (S8). This stops the ejection of the viscous fluid 9 from the nozzle 5. Note that if the viscosity μ of the medium 19A is not equal to or greater than the threshold μT and the forward rotation of the rotating body 10A is not being performed, the CPU 31 only stops the application of the pulse voltage by the pulse power supply 21 in the process of S8.

[0043] The CPU 31 drives the rotary motor 51 to start reverse rotation (S9). The viscous fluid 9 is pushed upward. The CPU 31 ends the main processing.

[0044] <Actions and Effects of This Embodiment> As described above, the coating device 1A has a rotating body 10A housed in the discharge section 2. The rotating body 10A has a shaft 11 and protrusions 12A. The shaft 11 is rotatable around the central axis C. The protrusions 12A protrude radially from the shaft 11. The coating device 1A coats the viscous fluid 9 by cooperation between the rotation of the rotating body 10A and the application of voltage by the pulsed power supply 21. In this way, the coating device 1A pushes out the viscous fluid 9 by the rotation of the rotating body 10A without changing the pressure inside the discharge section 2. Therefore, the coating device 1A can control the coating of the viscous fluid 9 at high speeds compared to when discharging by changing the pressure inside the discharge section 2.

[0045] In the coating device 1A, the center of the rotating body 10A coincides with the center of the housing 3 in the front-rear and left-right directions. As a result, the flow velocity U of the viscous fluid 9 is symmetrical about the central axis C. Therefore, the coating device 1A can extrude the viscous fluid 9 more efficiently than when the center of the rotating body 10A and the center of the housing 3 do not coincide.

[0046] In the coating device 1A, the lower end of the shaft 11 is the lower end of the rotating body 10A. The lower end of the shaft 11 is located between the vertical center of the housing 3 and the lower end of the housing 3. This means that the lower end of the rotating body 10A is relatively close to the nozzle 5 provided at the lower end of the housing 3. Therefore, the coating device 1A can efficiently extrude the viscous fluid 9 toward the nozzle 5.

[0047] In the coating device 1A, the CPU 31 controls the drive circuit 41 and power supply circuit 44 to synchronize the rotation of the rotating body 10A with the period T1 of the pulse voltage. In the coating device 1A, when the rotating body 10A rotates forward, droplets 90 of the viscous fluid 9 are pushed downward from the outlet of the nozzle 5. In this state, when the pulse power supply 21 turns on the pulse voltage, the viscous fluid 9 is ejected downward from the nozzle 5 due to Coulomb force. In the coating device 1A, the CPU 31 synchronizes the rotation of the rotating body 10A based on the period T1 of the pulse voltage. Therefore, the coating device 1A can eject the viscous fluid 9 efficiently.

[0048] In the coating device 1A, the CPU 31 acquires the viscosity μ of the viscous fluid 9 (S2). The CPU 31 determines whether the acquired viscosity μ of the medium 19A is equal to or greater than the threshold μT (S3). If the CPU 31 determines that the viscosity μ of the medium 19A is equal to or greater than the threshold μT, the CPU 31 starts forward rotation at a cycle T1 by driving the rotary motor 51 (S5). This allows the coating device 1A to control the coating of the viscous fluid 9 at high speed even when the viscosity μ of the viscous fluid 9 is high.

[0049] The coating device 1A has an electric heater 13 that heats the rotating body 10A. As a result, the electric heater 13 heats the viscous fluid 9 via the rotating body 10A, thereby reducing the viscosity μ of the viscous fluid 9. Furthermore, if the viscous fluid 9 has thermoplastic properties, such as a hot melt material, the electric heater 13 heats the viscous fluid 9 via the rotating body 10A, causing the viscous fluid 9 to melt. In this way, the coating device 1A can control the coating of the viscous fluid 9 at high speed even when the viscosity μ of the viscous fluid 9 is high or when the viscous fluid 9 has thermoplastic properties.

[0050] In the coating device 1A, the protrusions 12A extend spirally around the shaft 11. This makes it easier for the coating device 1A to control the amount of viscous fluid 9 extruded by the rotation of the rotor 10A.

[0051] In the coating device 1A, the rotating body 10A rotates to move the viscous fluid 9 in the up and down direction while stirring it. In this way, the protrusions 12A of the coating device 1A stir the viscous fluid 9, thereby making the viscous fluid 9 uniform within the discharge portion 2. Therefore, the coating device 1A can coat the viscous fluid 9 uniformly.

[0052] In the coating device 1A, the CPU 31 drives the rotary motor 51 to rotate in the forward direction, thereby pushing the viscous fluid 9 downward toward the outlet of the nozzle 5 (S5). The CPU 31 drives the rotary motor 51 to rotate in the reverse direction, thereby pushing the viscous fluid 9 upward (S9). In this way, the coating device 1A prevents the viscous fluid 9 from dripping from the nozzle 5 when the viscous fluid 9 is not being coated.

[0053] In the coating device 1A, the type of viscous fluid 9 includes ink. When the viscous fluid 9 is ink, the coating device 1A prints on the medium 19A as one mode of coating the medium 19A. By rotating the rotating body 10A, the coating device 1A can control printing on the medium 19A at high speed even when the viscosity μ of the ink is high.

[0054] In the coating device 1A, the type of viscous fluid 9 includes a hot melt material. The electric heater 13 heats the viscous fluid 9 via the rotor 10A. In this way, when the electric heater 13 heats the hot melt material, the hot melt material melts and the viscosity μ decreases. Therefore, even when coating the hot melt material, the coating device 1A can control the coating of the hot melt material onto the medium 19A at high speed.

[0055] <Modification> The present invention can be modified in various ways from the above-described embodiment. The various modifications described below can be combined with each other as long as no contradiction occurs.

[0056] A modified coating apparatus 1B will be described with reference to Fig. 7. The following mainly describes the differences between coating apparatus 1B and coating apparatus 1A. In coating apparatus 1B, components having the same shape or function as those in the above embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted or simplified.

[0057] Coating device 1B has rotor 10B instead of rotor 10A. Rotator 10B differs from rotor 10A in that it has protrusion 12B instead of protrusion 12A. Protrusion 12B is configured by a pair of blades 120 arranged vertically. The pair of blades 120 are arranged horizontally and are arranged symmetrically about central axis C. Rotator 10B also rotates forward to push viscous fluid 9 downward toward the outlet of nozzle 5. As with protrusion 12B, the protrusions of the rotor are not limited to extending spirally around axis 11, and the shape, number, and arrangement may be changed as appropriate, as long as they are structured to push viscous fluid 9 downward by rotating around axis 11.

[0058] In the coating device 1B, the positive electrode of the pulse power supply 21 is connected to the housing 3. Since the housing 3 has conductivity, the pulse voltage is also applied to the nozzle 5. Thus, any configuration in which a pulse voltage is applied to the nozzle 5 is acceptable, and the wiring on the positive electrode side of the pulse power supply 21 may be changed as appropriate.

[0059] In the coating device 1B, coating is performed on the medium 19B instead of the medium 19A. The medium 19B has conductivity. The negative electrode of the pulse power supply 21 is connected to the medium 19B. The coating device 1A does not have the counter electrode 18, and the table 17 supports the medium 19B. The pulse power supply 21 applies a pulse voltage between the discharge part 2 and the medium 19B. Thus, any configuration in which a voltage is applied between the nozzle 5 and the medium 19B is acceptable. The wiring on the negative electrode side of the pulse power supply 21 may be changed as appropriate. At this time, the medium 19B is an example of the "counter electrode" of the present invention.

[0060] Referring to FIGS. 8 to 10, a modification of the synchronization between the rotation of the rotating body 10A and the pulse voltage will be described. The modification of the synchronization shown in FIG. 8 shows the synchronization between the rotation of the rotating body 10A and the pulse voltage when the viscosity μ of the viscous fluid is greater than the viscosity μ of the viscous fluid 9 in the above-described embodiment. Since the viscosity μ of the viscous fluid is high, the length L of the droplet 90 of the viscous fluid gradually increases from the start of rotation of the rotating body 10A. The CPU 31 rotates the rotating body 10A in the positive direction for a time t2 (s). The time t2 is longer than the time t1 (s) and shorter than the period T1 (t1 < t2 < T1). The length L of the droplet 90 of the viscous fluid 9 reaches the length L1. The CPU 31 turns on the pulse voltage for a time t1, and then turns off the pulse voltage for a time t1. The CPU 31 stops the rotation of the rotating body 10A for a time (T1 - t2) to synchronize the rotation of the rotating body 10A with the period T1 of the pulse voltage.

[0061] The modified synchronization shown in FIG. 9 illustrates synchronization between the rotation of the rotating body 10A and the pulse voltage when the length L of the droplet 90 of the viscous fluid 9 is changed to length L2 (L2>L1). The CPU 31 rotates the rotating body 10A forward for time t3 (s) and turns off the pulse voltage. Time t3 is longer than time t1 (t3>t1). The length L of the droplet 90 of the viscous fluid 9 reaches length L2. Thereafter, the CPU 31 stops the rotation of the rotating body 10A for time t1 and turns on the pulse voltage. The CPU 31 synchronizes the rotation of the rotating body 10A and the application of the pulse voltage with a period T2 (s). The period T2 is the sum of time t3 and time t1 (T2=t3+t1).

[0062] The modified example of synchronization shown in FIG. 10 illustrates synchronization between the rotation of the rotating body 10A and the pulse voltage when droplets 90 of the viscous fluid 9 having a length L2 and droplets 90 of the viscous fluid 9 having a length L1 are alternately ejected. The CPU 31 rotates the rotating body 10A in the forward direction for a time t1 and turns off the pulse voltage. The length L of the droplets 90 of the viscous fluid 9 reaches the length L1. The CPU 31 stops the rotation of the rotating body 10A and turns on the pulse voltage. The droplets 90 of the viscous fluid 9 having a length L1 are ejected from the nozzle 5. The CPU 31 rotates the rotating body 10A in the forward direction for a time t3 and turns off the pulse voltage. The length L of the droplets 90 of the viscous fluid 9 reaches the length L2. The CPU 31 stops the rotation of the rotating body 10A and turns on the pulse voltage. The droplets 90 of the viscous fluid 9 having a length L2 are ejected from the nozzle 5. CPU 31 synchronizes the rotation of rotor 10A with the application of the pulse voltage at a period T3 (s), which is the sum of time t3 and three times time t1 (T3=t3+(3×t1)).

[0063] Other modified examples will now be described. In the above embodiment, the rotation of the rotating body 10A causes the droplets 90 of the viscous fluid 9 to extend downward from the nozzle 5, and the application of a pulse voltage causes the droplets 90 of the viscous fluid 9 to be peeled off from the nozzle 5. In contrast, the rotation of the rotating body 10A and the application of a pulse voltage may work together to cause the droplets 90 of the viscous fluid 9 to extend downward from the nozzle 5. The rotation of the rotating body 10A and the application of a pulse voltage may work together to cause the droplets 90 of the viscous fluid 9 to be peeled off from the nozzle 5.

[0064] In the above embodiment, the direction in which the rotating body 10A pushes out the viscous fluid 9 by rotation and the discharge direction D are both downward. In contrast, the direction in which the rotating body 10A pushes out the viscous fluid 9 by rotation only needs to include a directional component of the discharge direction D, and may be inclined with respect to the discharge direction D. In the above embodiment, the viscous fluid 9 is discharged downward, but the discharge direction D is not limited to downward.

[0065] The rotating body 10A may be housed in the discharge part 2, for example, in the nozzle 5. The number of rotating bodies 10A is not limited to one, and may be two or more. The shaft 11 may be rotatable within the discharge part 2, and the entire shaft 11 may be housed in the discharge part 2. The structure of the shaft 11 may be modified as appropriate, and may be, for example, a disk shape with the central axis C as its axis, or a prismatic shape with the central axis C as its geometric center.

[0066] The center of the rotating body 10A and the center of the housing 3 do not have to coincide. The center of the rotating body 10A and the center of the housing 3 only have to coincide in a direction intersecting the up-down direction. For example, when the center of the rotating body 10A and the center of the housing 3 coincide in the left-right direction, the center of the rotating body 10A and the center of the housing 3 do not have to coincide in the front-to-back direction. When the center of the rotating body 10A and the center of the housing 3 coincide in the front-to-back direction, the center of the rotating body 10A and the center of the housing 3 do not have to coincide in the left-to-right direction.

[0067] The lower end of rotating body 10A does not have to be located between the vertical center of housing 3 and the lower end of housing 3. The lower end of rotating body 10A may not be the lower end of shaft 11, but may be the lower end of protrusion 12A.

[0068] The coating device 1A is not limited to applying a voltage from the pulse power supply 21. The coating device 1A may apply a voltage between the discharge portion 2 and the counter electrode 18 from a DC power supply that applies a DC voltage, an AC power supply that applies a sinusoidal AC voltage, or the like, instead of the pulse power supply 21. In this case, the coating device 1A may have a circuit that converts the voltage output from the DC power supply or the AC power supply into a pulse voltage.

[0069] The coating device 1A does not need to control the rotation of the rotating body 10A using the CPU 31. The CPU 31 is not limited to rotating the rotating body 10A when the viscosity μ is equal to or greater than the threshold μT. That is, the CPU 31 may rotate the rotating body 10A when the viscosity μ is equal to or less than the threshold μT. In this case, the processes of S2 to S4 may be omitted in the main processing. The CPU 31 acquires the viscosity μ of the viscous fluid 9 stored in the ROM 32 in the process of S2. Alternatively, the CPU 31 may acquire the viscosity μ of the viscous fluid 9 input by the user via the input unit 35, or may acquire the viscosity μ of the viscous fluid 9 measured by a viscometer.

[0070] In the above embodiment, the protrusions 12A of the rotor 10A rotate around the axis 11 to push the viscous fluid 9 downward and agitate the viscous fluid 9 within the discharge portion 2. In contrast, the protrusions 12A do not necessarily have to agitate the viscous fluid 9 within the discharge portion 2.

[0071] The rotor 10A does not have to rotate in the reverse direction as long as it rotates in the forward direction to push the viscous fluid 9 downward. In this case, the processes of S1 and S9 may be omitted from the main process.

[0072] The type of the viscous fluid 9 may be changed as appropriate. The type of the viscous fluid 9 does not have to include ink. When the type of the viscous fluid 9 is ink, the viscosity μ of the ink is not limited to the viscosity μ of the above embodiment.

[0073] The type of viscous fluid 9 may be changed as appropriate. The type of viscous fluid 9 does not have to include a hot melt material. When the type of viscous fluid 9 is a hot melt material, the viscosity μ of the hot melt material is not limited to the viscosity μ of the above embodiment. The coating device 1A does not have to heat the hot melt material with the electric heater 13. In this case, the coating device 1A does not have to have the electric heater 13. The coating device 1A may have a heater that heats the discharge section 2. The coating device 1A may heat the rotating body 10A with a heater other than the electric heater 13. The coating device 1A may heat the rotating body 10A with, for example, a hot air heater that sprays hot air.

[0074] The coating device 1A may use, for example, a microcomputer, an ASIC (Application Specific Integrated Circuits), an FPGA (Field Programmable Gate Array), etc. for control instead of the CPU 31. The main processing may be distributed using a plurality of CPUs 31, or may be performed by combining the CPU 31 with an ASIC, etc.

[0075] Non-transitory storage media such as ROM 32 and storage device 34 may be any storage media capable of retaining information regardless of the period for which the information is stored. Non-transitory storage media do not have to include temporary storage media (e.g., transmitted signals). The program for executing the main processing may be downloaded (i.e., transmitted as a transmission signal) from a server connected to the network and stored in storage device 34 or the like. In this case, the program or the like may be stored in a non-transitory storage medium such as an HDD provided in the server.

[0076] <Other> The pulse power supply 21 is an example of a "power supply" of the present invention. The front-rear direction and the left-right direction are examples of a "crossing direction" of the present invention. The CPU 31 is an example of a "controller" of the present invention. The electric heater 13 is an example of a "heater" of the present invention. [Explanation of symbols]

[0077] 1 Coating device 2 Discharge part 3. Housing 5 nozzles 9 Viscous fluid 10A, 10B Rotating body 11 axes 12A, 12B protrusion 13 Electric heater 21 Pulse power supply 31 CPU 51 Rotary motor

Claims

1. a discharge unit having a housing that contains a viscous fluid and a nozzle; a counter electrode facing the nozzle; a power source that applies a voltage between the counter electrode and the ejection portion; a rotating body that has a rotatable shaft and a protrusion that protrudes from the shaft in a direction intersecting the shaft, is housed in the discharge part, and rotates to push the viscous fluid from the nozzle in a discharge direction toward the counter electrode, and discharges the viscous fluid from the nozzle in cooperation with the power source that applies the voltage. A coating device characterized by:

2. The coating device according to claim 1 , wherein a center of the rotating body in the intersecting direction coincides with a center of the housing in the intersecting direction.

3. the nozzle is formed at an end of the housing in the ejection direction, the nozzle and the counter electrode face each other in the ejection direction, The lower end of the rotating body is located between the center of the housing in the discharge direction and the end of the housing in the discharge direction. The coating device according to claim 1 ,

4. Further comprising a controller, The power supply applies a pulse voltage at a predetermined cycle, The controller synchronizes the rotation of the rotating body based on the period. The coating device according to claim 1 ,

5. Further comprising a controller, The controller obtaining the viscosity of the viscous fluid; determining whether the acquired viscosity is equal to or greater than a threshold value; rotating the rotor when it is determined that the viscosity is equal to or greater than the threshold value; The coating device according to claim 1 ,

6. The coating device according to claim 1, further comprising a heater for heating the rotating body.

7. The coating device according to claim 1 , wherein the protrusion of the rotating body extends spirally around the axis.

8. The coating device according to claim 7, wherein, when the shaft of the rotating body rotates, the protrusions push out the viscous fluid in the discharge direction and agitate the viscous fluid within the discharge portion.

9. Further comprising a controller, The rotor is capable of rotating forward and backward, The controller The rotating body is rotated in the forward direction to push out the viscous fluid in the ejection direction. By rotating the rotor in the reverse direction, the viscous fluid is pushed up in a direction opposite to the ejection direction. The coating device according to claim 1 ,

10. 2. The coating device according to claim 1, wherein the viscous fluid is ink for printing on a medium.

11. the viscous fluid is a hot melt material, The coating device according to claim 6 , wherein the heater heats the viscous fluid contained in the housing.

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