coating device

Abstract

To obtain a coating apparatus which hardly causes coating unevenness when coating is resumed, even after supply of a coating material to a nozzle has been stopped for a long period.SOLUTION: A coating apparatus comprises: a nozzle for discharging a coating material; a state switching mechanism for switching between a supply state of supplying the coating material to the nozzle, and a supply stop state of stopping supply of the coating material to the nozzle; and an agitation mechanism for agitating a coating material which has accumulated at a downstream side beyond the state switching mechanism, in the supply stop state.SELECTED DRAWING: Figure 6

Description

Technical Field

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

Background Art

[0002] As a coating device for coating a base material such as a traveling film with a paint, Patent Document 1 discloses a nozzle for discharging the paint, an intermittent means for repeatedly supplying and stopping the paint to the nozzle, and a paint suction piston provided between the nozzle and the intermittent means. The piston sucks the paint from the nozzle in accordance with the timing of stopping the supply of the paint to the nozzle by the intermittent means, and returns the sucked paint to the nozzle in accordance with the timing of starting the supply of the paint to the nozzle by the intermittent means. According to this coating device, the piston reciprocates in conjunction with the supply and stop of the paint by the intermittent means, and the paint is stirred by the movement of the piston. As a result, the substances contained in the paint are dispersed, and the paint can be uniformly applied to the base material.

[0003] However, in the coating device disclosed in Patent Document 1, when the intermittent means is kept in the stopped state, the piston stops operating. Therefore, when kept in the stopped state, the paint accumulated on the downstream side of the intermittent means is not stirred, and the substances contained in the paint settle. For this reason, when coating is restarted from this state, there is a problem that coating unevenness occurs until the paint accumulated on the downstream side of the intermittent means is stirred, and the yield deteriorates. In particular, when the stopped state continues for a long time due to maintenance or the like, it takes time for this stirring, and the coating unevenness continues for a long time, resulting in a very poor yield.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, the main objective of the present invention is to provide a coating apparatus that is less prone to uneven coating when coating is resumed, even after the supply of paint to the nozzle has been stopped for a long period of time. [Means for solving the problem]

[0006] The coating apparatus according to the present invention is characterized by comprising: a nozzle for discharging paint; a state switching mechanism that switches between a supply state in which the paint is supplied to the nozzle and a supply stop state in which the supply of the paint to the nozzle is stopped; and a stirring mechanism that stirs the paint accumulated downstream of the state switching mechanism in the supply stop state.

[0007] With this configuration, even if the supply is interrupted for an extended period due to maintenance, for example, the paint accumulated between the nozzle and the state switching mechanism can be agitated, so the substances contained in the paint are dispersed and sedimentation is less likely to occur. As a result, uneven coating can be suppressed when coating is resumed, and the yield is improved.

[0008] Furthermore, the state switching mechanism may include a piston that moves between an open position that opens the flow path through which the paint flows and a closed position that closes the flow path, and the piston is configured such that when it moves to the open position, it switches to the supply state, and when it moves to the closed position, it switches to the supply stop state, and the piston is configured to move within a predetermined section including the closed position while closing the flow path, and the stirring mechanism may be configured to stir by the piston moving back and forth within the predetermined section.

[0009] With this configuration, the piston reciprocates while blocking the flow path, allowing the paint accumulated between the nozzle and the state switching mechanism to be agitated while maintaining a supply stop state. Furthermore, since the piston constituting the state switching mechanism also serves as the agitation mechanism, there is no need to provide a separate agitation mechanism. As a result, the device can be made smaller and manufacturing costs can be reduced.

[0010] Furthermore, the stirring mechanism may be configured to stir by a piston that reciprocates within a section connecting the blocked position and a second blocked position located upstream of the blocked position.

[0011] With this configuration, the piston reciprocates during stirring without moving downstream of the occluded position, so paint does not leak from the nozzle.

[0012] Furthermore, the closed position may be located upstream of the open position.

[0013] With this configuration, when switching to a supply-stop state, the piston moves from the open position to the closed position, drawing the paint accumulated between the nozzle and the piston upstream. As a result, the paint can be applied to the substrate cleanly and efficiently.

[0014] Furthermore, the system may also include a pump provided upstream of the state switching mechanism for supplying paint to the nozzle, and a recirculation mechanism that, in the supply stop state, recirculates the paint supplied from the pump to the upstream side of the pump.

[0015] With this configuration, when the supply is stopped, the paint upstream of the piston continues to circulate, making sedimentation less likely. As a result, uneven coating can be further suppressed when coating is resumed. [Effects of the Invention]

[0016] Thus, with the coating apparatus according to the present invention, even after the supply of paint to the nozzle has been stopped for a long period of time, uneven coating is less likely to occur when coating is resumed. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic diagram showing the entire coating apparatus of the embodiment. [Figure 2] This is a partially enlarged schematic diagram showing the supply state of the coating apparatus of the embodiment. [Figure 3]It is a partially enlarged schematic view showing the supply stop state of the coating apparatus of the embodiment. [Figure 4] It is a partially enlarged schematic view showing the state switching mechanism of the coating apparatus of the embodiment. [Figure 5] It is a partially enlarged schematic view showing the operation of the state switching mechanism of the coating apparatus of the embodiment. [Figure 6] It is a partially enlarged schematic view showing the operation of the state switching mechanism of the coating apparatus of the implementation neglect. [Figure 7] It is a partially schematic view showing the coating apparatus of another embodiment.

Mode for Carrying Out the Invention

[0018] The coating apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7.

[0019] <Embodiment> The coating apparatus 100 of the present embodiment is an apparatus for applying paint to a base material B such as a traveling film as shown in FIGS. 1 to 6. The coating apparatus 100 includes a nozzle 10 that discharges paint, a pump 20 that sends the paint to the nozzle 10, a state switching mechanism 30 provided in the middle of a supply pipe L1 connected to the nozzle 10 and the pump 20, and a reflux mechanism 40 provided in the middle of a reflux pipe L2 that branches from the upstream side of the state switching mechanism 30 of the supply pipe L1 and is connected to the upstream side of the pump 20, and a control unit 50 that controls the state switching mechanism 30 and the reflux mechanism 40.

[0020] The nozzle 10, which is also called a die, has a slit-shaped discharge port 11 at the tip facing the base material B side as shown in FIGS. 2 to 6. This nozzle 10 is installed so that the discharge port 11 extends in the width direction (direction orthogonal to the traveling direction) of the base material B.

[0021] As shown in FIG. 1, the pump 20 pumps the paint stored in the storage tank T to the nozzle 10 and is installed on the downstream side of the storage tank T. In the present embodiment, one end of the reflux pipe L2 is connected to the storage tank T.

[0022] The state switching mechanism 30 switches between a supply state in which paint pumped from the pump 20 is supplied to the nozzle 10 and a supply stop state in which the supply of paint to the nozzle 10 is stopped. Specifically, as shown in Figures 2 and 3, the state switching mechanism 30 comprises a supply pipe section 31 which is part of the supply pipe L1, a switching seal member 32 provided on the inner circumferential surface of the supply pipe section 31, a switching piston 33 which moves back and forth in the extension direction within the supply pipe section 31, and a switching drive mechanism 34 which drives the switching piston 33.

[0023] The supply pipe section 31 comprises the area between the branching point of the supply pipe L1 with the return pipe L2 and the nozzle 10. The supply pipe section 31 is formed in the shape of a straight circular pipe of the same diameter in the section in which the switching piston 33 moves.

[0024] The switching seal member 32 is an annular (tubular) elastically deformable member and is attached to a predetermined location on the inner circumferential surface of the supply pipe section 31. The inner diameter of this switching seal member 32 is smaller than the inner diameter of the supply pipe section 31.

[0025] The switching piston 33 has a cylindrical portion 33a of the same diameter. The outer diameter of this portion 33a is smaller than the inner diameter of the supply pipe 31 and larger than the inner diameter of the switching seal member 32 in its natural state. The switching piston 33 moves back and forth along the extending direction of the supply pipe 31 between a supply passage open position P1 (see Figure 2) where the portion 33a is detached from the switching seal member 32 and a supply passage closed position P2 (see Figure 3) where the portion 33a is engaged with the switching seal member 32. When the switching piston 33 moves to the supply passage open position P1, a gap is formed between the outer circumferential surface of the portion 33a and the inner circumferential surface of the supply pipe 31, and paint flows to the nozzle 10 through this gap. In other words, the supply passage in the supply pipe L1 is opened, and the supply state is established. On the other hand, when the switching piston 33 moves to the supply path closed position P2, the gap formed between the outer circumferential surface of the same-diameter portion 33a and the inner circumferential surface of the supply pipe portion 31 is sealed by the switching sealing member 32, and paint stops flowing to the nozzle 10. In other words, the supply path in the supply pipe L1 is closed, and the supply is stopped. In this embodiment, the supply path open position P1 is set downstream of the supply path closed position P2.

[0026] Furthermore, as shown in Figure 4, the same-diameter portion 33a has a predetermined length x in the axial direction, so the switching piston 33 moves while engaging with the switching seal member 32 for this length x. The section X in which the switching piston 33 moves while engaging with the switching seal member 32 is the predetermined section in the claim. In other words, this predetermined section X has a length x between the upstream end and the downstream end of the same-diameter portion 33a. The supply path closure position P2 is set within the range of this predetermined section X, and the supply path opening position P1 is set downstream of this predetermined section X.

[0027] The switching drive mechanism 34 moves the switching piston 33 back and forth between a supply path open position and a supply path closed position. As shown in Figures 2 and 3, the switching drive mechanism 34 includes a switching motor 34a provided outside the supply pipe section 31, and a switching conversion mechanism (not shown) that converts the rotation of the switching motor 34a into reciprocating linear motion and transmits it to a rod 34b connected to the switching piston 33. Examples of the switching conversion mechanism include a rack and pinion mechanism and a slider-crank mechanism.

[0028] The recirculation mechanism 40 switches between a recirculation state in which the paint pumped from the pump 20 flows into the recirculation pipe L2, and a recirculation stop state in which the paint pumped from the pump 20 does not flow into the recirculation channel L2. Specifically, the recirculation mechanism 40 comprises a recirculation pipe section 41 which is part of the recirculation pipe L2, a recirculation sealing member 42 provided on the inner circumferential surface of the recirculation pipe section 41, a recirculation piston 43 which moves back and forth in the direction of extension within the recirculation pipe section 41, and a recirculation drive mechanism 44 which drives the recirculation piston 43.

[0029] The recirculation pipe section 41 is formed in the shape of a straight circular tube of the same diameter in at least the section in which the recirculation piston 43 moves.

[0030] The recirculation sealing member 42 is an annular (tubular) elastically deformable member and is attached to a predetermined location on the inner circumferential surface of the recirculation pipe section 41. The inner diameter of this recirculation sealing member 42 is smaller than the inner diameter of the recirculation pipe section 31.

[0031] The recirculation piston 43 is cylindrical in shape, with an outer diameter smaller than the inner diameter of the recirculation pipe section 41 and larger than the inner diameter of the recirculation seal member 42 in its natural state. The recirculation piston 43 moves back and forth along the extending direction of the recirculation pipe section 41 between a recirculation channel closure position Q1 (see Figure 2) where it engages with the recirculation seal member 42 and a recirculation channel open position Q2 (see Figure 3) where it is disengaged from the recirculation seal member 42. When the recirculation piston 43 moves to the recirculation channel closure position Q1, the gap formed between its outer surface and the inner surface of the recirculation pipe section 41 is sealed by the recirculation seal member 42, and paint recirculation stops. In other words, the recirculation channel in the recirculation pipe L2 is closed, and recirculation stops. On the other hand, when the recirculation piston 43 moves to the recirculation channel open position Q2, a gap is formed between its outer surface and the inner surface of the recirculation pipe section 41, and paint recirculates through this gap. In other words, the reflux channel within reflux pipe L2 is opened, and reflux conditions are established.

[0032] The recirculation drive mechanism 44 moves the recirculation piston 43 back and forth between a recirculation channel closed position Q1 and a recirculation channel open position Q2. The recirculation drive mechanism 44 includes a recirculation motor 44a provided outside the recirculation pipe L2, and a recirculation conversion mechanism (not shown) that converts the rotation of the recirculation motor 44a into reciprocating linear motion and transmits it to a rod 44b connected to the recirculation piston 43. Examples of the recirculation conversion mechanism include a rack and pinion mechanism and a slider-crank mechanism.

[0033] The control unit 50 is a general-purpose or dedicated computer or PLC equipped with a CPU, memory, input / output interface, etc., and controls the state switching mechanism 30 and the return mechanism 40 by coordinating the CPU and peripheral devices according to a predetermined program stored in its memory.

[0034] However, the coating apparatus 100 of this embodiment further includes a stirring mechanism 60 for stirring the paint that remains between the nozzle 10 and the state switching mechanism 30 when the supply is stopped. The stirring mechanism 60 includes a stirring member 61 that moves inside the supply pipe L1 and a stirring drive mechanism 62 that drives the stirring member 61, and is controlled by the control unit 50. In this embodiment, the switching piston 33 also serves as the stirring member 61, and the switching drive mechanism 34 also serves as the stirring drive device 62.

[0035] Next, the operation of the coating apparatus 100 of this embodiment will be described.

[0036] When the coating start signal is received, the control unit 50 alternately repeats two controls to intermittently apply paint to the substrate B. In detail, first, as shown in Figure 2, the control unit 50 controls the switching drive mechanism 34 to move the switching piston 33 to the supply path open position P1, and controls the recirculation drive mechanism 44 to move the recirculation piston 43 to the recirculation path closed position Q1. In other words, the control unit 50 switches the state switching mechanism 30 to the supply state and switches the recirculation mechanism 40 to the recirculation stop state. As a result, all of the paint pumped from the pump 20 is applied to the substrate B without being recirculated. Hereafter, this control will also be referred to as coating control. Next, as shown in Figure 3, the control unit 50 controls the switching drive mechanism 34 to move the switching piston 33 to the supply path closed position P2, and controls the recirculation drive mechanism 44 to move the recirculation piston 43 to the recirculation path open position Q2. In other words, the control unit 50 switches the state switching mechanism 30 to the supply stop state and switches the recirculation mechanism 40 to the recirculation state. As a result, all of the paint pumped from the pump 20 is recirculated without being applied to the substrate B. Hereinafter, this control will also be referred to as the coating stop control.

[0037] Furthermore, since the supply path closure position P2 is set upstream of the supply path open position P1 and is located in the middle of a predetermined section X, when coating stop control is performed, the switching piston 33 slightly draws the paint from the nozzle 10 side upstream. This ensures that the paint is applied cleanly to the substrate B. More specifically, when coating stop control is performed after coating control has been performed, the switching piston 33 moves from the supply path open position P1 to the supply path closure position P2, as shown in Figure 5(a), and its upstream end engages with the switching seal member 32 along the way. As a result, the supply of paint to the nozzle 10 stops at this point. In this state, the downstream side of the switching piston 33 is filled with paint up to the discharge port 11 of the nozzle 10. When the switching piston 33 moves further to the supply path closure position P2, as shown in Figure 5(b), the paint from the nozzle 10 side is slightly drawn upstream. Therefore, in this state, the downstream side of the switching piston 33 is not filled with paint up to the discharge port 11 of the nozzle 10.

[0038] When a coating stop signal is input to the control unit 50, it performs coating stop control and then stops the two aforementioned controls. Then, for example, if a coating start signal is not input for a predetermined time after a coating stop signal is input, the control unit 50 causes the switching piston 33 to reciprocate within a predetermined section X. More specifically, as shown in Figures 6(a) and 6(b), the control unit 50 causes the switching piston 33 to reciprocate within a predetermined section X. Specifically, in this embodiment, the control unit 50 causes the switching piston 33 to reciprocate in the section connecting the supply path closure position P2 and a second supply path closure position P3 set downstream of this supply path closure position P2. In this embodiment, the second supply path closure position P3 is the position where the upstream end of the switching piston 33 engages with the switching seal portion 32. This stirs the paint that is accumulating between the nozzle 10 and the state switching mechanism 30.

[0039] Furthermore, when coating stop control is performed, the paint on the nozzle 10 side is slightly sucked upstream by the switching piston 33. As long as the upstream end of the switching piston 30 does not move downstream beyond the position where it engages with the switching seal portion 32 during stirring (in this embodiment, the second supply path closing position P3), paint will not leak from the nozzle 10.

[0040] According to the coating apparatus 100 of this embodiment, the switching piston 33 can be moved back and forth while maintaining a supply stop state. Therefore, even if the supply stop state continues for a long period of time, for example, due to maintenance, the paint accumulated between the nozzle 10 and the state switching mechanism 30 can be agitated. As a result, sedimentation of the accumulated paint is less likely to occur, and uneven coating can be suppressed when coating is resumed.

[0041] Furthermore, by setting a predetermined section (supply path closed position P2) upstream of the supply path open position P1, and configuring the switching piston 33 to reciprocate within the predetermined section X during stirring, paint accumulated between the nozzle 10 and the state switching mechanism 30 does not leak from the nozzle 10 during stirring.

[0042] Furthermore, since the switching piston 33 of the state switching mechanism 30 is configured to also function as the stirring member 61 of the stirring mechanism 60, the stirring mechanism 60 can be added to a conventional coating device equipped with the state switching mechanism 30 simply by modifying the control program.

[0043] <Other Embodiments> However, the present invention is not limited to the embodiments described above.

[0044] In the above embodiment, the state switching mechanism is configured to also function as the stirring mechanism, but a separate stirring mechanism may be provided between the nozzle and the state switching mechanism. In this case, for example, the stirring mechanism may be configured such that the stirring member reciprocates in a direction perpendicular to the axial direction of the supply pipe.

[0045] Furthermore, in the above embodiment, the switching seal member was fixed to the inner circumferential surface of the supply pipe section, but as shown in Figure 4, for example, the switching seal member 32 may be fixed to the outer circumferential surface of the switching piston 33. In this case, the supply pipe section 31 is provided with a small-diameter section 31a, which has an inner diameter smaller than the outer diameter of the switching seal member 32 when it is fixed to the switching piston 33, and a large-diameter section 31b, which has an inner diameter larger than the outer diameter of the switching seal member 32 when it is fixed to the switching piston 33. As a result, when the switching piston 33 moves to the small-diameter section 31a, the gap between the inner circumferential surface of the small-diameter section 31a and the outer circumferential surface of the switching piston 33 is sealed by the switching seal member 32, and the supply is switched to the stopped state. On the other hand, when the switching piston 33 moves to the large-diameter section 31b, the gap between the inner circumferential surface of the large-diameter section 31b and the outer circumferential surface of the switching piston 33 is not completely sealed by the switching seal member 32, and the supply is switched to the supply state. With this configuration, when the supply is stopped, the switching piston 33 can be moved back and forth within the small-diameter section 31a, thereby agitating the paint accumulated between the nozzle and the state switching mechanism while maintaining that state.

[0046] Furthermore, in the stirring mechanism of the above embodiment, the switching piston is configured to reciprocate in the section connecting the supply path closure position and the second supply path closure position downstream of that position in order to prevent paint leakage during stirring. However, it is sufficient to reciprocate within a predetermined section, and for example, reciprocating within the section connecting the supply path closure position and the second supply path closure position upstream of that position will similarly prevent paint leakage.

[0047] Furthermore, in the above embodiment, a predetermined section (supply path closure position) was set upstream of the supply path open position, but a predetermined section (supply path closure position) may also be set downstream of the supply path open position. In this case, in order to prevent paint leakage during stirring, the switching piston needs to be moved back and forth within the section connecting the supply path closure position and a second supply path closure position upstream of that position. In other words, regardless of whether the predetermined section is set upstream or downstream of the supply path open position, paint leakage can be prevented by moving the switching piston back and forth within the section connecting the supply path closure position and a second supply path closure position upstream of that position.

[0048] Furthermore, in the above embodiment, the control unit is configured to automatically start stirring control if no coating start signal is input for a predetermined time after the supply has stopped. However, the control unit may also be configured to start stirring control when it receives a stirring start signal after the supply has stopped.

[0049] Furthermore, although a recirculation mechanism was provided in the above embodiment, it is not necessarily required to provide a recirculation mechanism.

[0050] Furthermore, although the coating apparatus of the above embodiment intermittently applies paint to the substrate, the coating apparatus does not necessarily have to apply intermittently; for example, it may apply continuously.

[0051] Furthermore, although the nozzle in the above embodiment has a slit-shaped discharge port called a die, it may also be cylindrical, for example, having a circular discharge port.

[0052] Furthermore, various combinations or modifications of parts of the embodiments are permitted, as long as they do not contradict the spirit of the present invention. [Explanation of symbols]

[0053] 100: Coating device 10: Nozzle 20: Pump L1: Supply pipe L2: Reflux tube 30: State switching mechanism 31: Supply pipe section 32: Switching sealing member 33: Switching piston P1: Supply path open position P2: Supply path blockage position P3: Second supply path blockage location 34: Switching drive mechanism 40; Reflux mechanism 41: Reflux pipe section 42: Recirculation sealing member 43: Recirculation piston Q1: Return path blockage position Q2: Location of open flow path 44: The driving mechanism is still in use. 50: Control Department 60: Stirring mechanism 61: Mixing components

Claims

1. A nozzle that dispenses paint, A state switching mechanism is provided, comprising a piston that moves between an open position that opens the flow path through which the paint flows and a closed position that closes the flow path, wherein when the piston moves to the open position, it switches to a supply state in which the paint is supplied to the nozzle, and when it moves to the closed position, it switches to a supply stop state in which the supply of the paint to the nozzle is stopped, In the aforementioned supply stop state, the system is equipped with a stirring mechanism that stirs the paint accumulated downstream of the state switching mechanism, The piston is configured to move within a predetermined section including the closed position while blocking the flow path. A coating apparatus characterized in that the stirring mechanism is configured to stir by a piston that reciprocates within a predetermined section.

2. The coating apparatus according to claim 1, wherein the stirring mechanism is configured to stir by a piston that reciprocates within a section connecting the closed position and a second closed position upstream of the closed position.

3. The coating apparatus according to claim 1, wherein the predetermined section is provided upstream of the open position.

4. A pump is provided upstream of the state switching mechanism to supply paint to the nozzle, The coating apparatus according to claim 1, further comprising a recirculation mechanism for recirculating the paint sent from the pump to the upstream side of the pump in the aforementioned supply stop state.

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