JP4152489B2 - Roll coater with hermetically sealed coating tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In order to prevent transpiration of solvents and the like, there is a roll coater in which a coating liquid tank is sealed. The present invention relates to a roll coater, particularly a gravure coater, equipped with this type of coating solution tank.
[0002]
[Prior art]
In this type of roll coater, a lower surface immersion type in which the lower peripheral surface of the coating roller is immersed in the coating liquid, and a coating liquid tank is disposed in close contact with the roller peripheral surface of the coating roller so that the roller peripheral surface is provided. There is a side immersion type that is immersed in the coating liquid.
[0003]
The roll coater disclosed in Japanese Utility Model Laid-Open No. 61-61056 belongs to the former, and as shown in FIG. 5, a coating roller 46 is accommodated in a coating liquid tank 45 having a C-shaped section opening upward. The gap between the coating roller 46 and the opening edge of the coating liquid tank 45 is closed with a doctor 47 and a lid material 48. The coating tank 45 is composed of a pair of divided tank bodies 45a and 45a that are divided forward and backward by a vertical plane that passes through the roller central axis, and a pair of left and right end walls 45b that block the opening of the end faces of both divided tank bodies 45a. The coating roller 46 is pivotally supported by the left and right end walls 45b. An overflow port 49 is provided near the upper end of one divided tank body 45a, and the liquid level of the coating liquid is set so high that about 70% of the roller peripheral surface is submerged in the liquid.
[0004]
As shown in FIG. 6, the side surface immersion type roll coater includes a square box-shaped coating liquid tank 50, and an immersion port 52 that receives the peripheral surface of the coating roller 51 is opened on one side surface thereof. The upper edge of the immersion port 52 is sealed with a doctor 53 and the lower edge is sealed with a seal body 54.
[0005]
[Problems to be solved by the invention]
In the coater with the coating liquid tank sealed, evaporation of solvents and the like can be prevented well, but there is a problem of poor coating caused by bubbles adhering to the coating roller. Bubbles and bubbles are generated by the dropping of the excess coating liquid scraped off by the doctor, and are further generated by the bubble mass brought into the coating liquid by the coating roller. In particular, when the coating roller 46 is a gravure coater, air is easily brought into the coating liquid by cells on the roller surface, and bubbles are easily generated. Since the coating liquid tank 45 is hermetically sealed, the generated foam cannot be removed, and when the foam adheres to the cell, dislocation of the coating liquid in the foam-adhered portion is prevented, resulting in poor coating. In addition, since the liquid level of the coating liquid is high, there is a disadvantage that a large amount of residual liquid is left in the tank at the end of the coating, and the disposal costs a lot. Since the surplus liquid scraped off by the doctor 47 is returned into the coating liquid tank 45, depending on the inclination angle of the doctor 47, the surplus liquid may collide with the liquid surface in the tank and generate bubbles.
[0006]
Since the peripheral surface length exposed to the air of the coating roller 51 is large in the side immersion type roll coater, the roller peripheral surface is easy to dry, and when the coating roller 51 is a gravure roller, the cell is clogged. May result in poor coating. Since the doctor 53 and the seal body 54 are pressed against the roller peripheral surface to seal the coating liquid tank 50, the seal body 54 and the doctor 53 are easily worn out, and the seal body is increased as the operating time of the coater is prolonged. The coating liquid tends to leak from the contact end 54. Since the immersion port 52 is formed in accordance with the curvature of the peripheral surface of the coating roller 51, it is necessary to prepare a dedicated coating tank 50 corresponding to the change in the diameter of the coating roller 51. There is also a disadvantage that can not cope with the change of diameter.
[0007]
The purpose of the present invention is to suppress the generation of bubbles due to air entrainment in a roll coater, and forcibly remove bubbles adhering to the peripheral surface of the roller, thereby reliably eliminating coating defects associated with adhesion of bubbles. There is to do.
An object of the present invention is to reduce the cost required for web coating processing equipment by the amount that the coating roller having a different diameter size can be exchanged and mounted as needed, and thus the coating liquid tank can be shared.
The object of the present invention is to reduce the amount of coating liquid stored in the coating tank during web processing as much as possible, thereby reducing the amount of residual liquid at the end of coating and reducing the cost required for disposal. There is.
An object of the present invention is to obtain a roll coater provided with a hermetically sealed coating liquid tank suitable for a gravure roller having a cell group formed on the roller peripheral surface.
[0008]
[Means for Solving the Problems]
In the roll coater of the present invention, the coating roller 1 and the coating liquid are accommodated in the coating liquid tank 3 whose upper surface is open as shown in FIG. A gap between the opening edge of the coating liquid tank 3 and the peripheral surface of the coating roller 1 is closed by the doctor 15 and the seal plate 14 that circumscribe the peripheral surface of the coating roller 1. Inside the coating liquid tank 3, a finisher roller 23 that is in contact with the lower peripheral surface of the coating roller 1 and forcibly removing bubbles is disposed so as to be immersed in the coating liquid. A partition wall 32 is disposed between the finisher roller 23 and the doctor 15 along the lower peripheral surface of the coating roller 1, and the inside of the coating liquid tank 3 is scraped off by the coating liquid chamber 30 and the doctor 15. It is divided into a return liquid chamber 31 that receives and recirculates the excess coating liquid.
[0009]
The coating liquid tank 3 includes a pair of divided tank bodies 3A and 3B that are divided forward and backward on a plane passing through the central axis of the coating roller 1. Both the divided tank bodies 3A and 3B are connected so as to be swingable and openable by a shaft 4 disposed on the outer surface of the peripheral wall, and the coating roller 1 can be exchanged and mounted in the open state. As shown in FIG. 3, bearing parts 12 and 12 for holding the shaft part 11 of the coating roller 1 are formed on the divided surfaces of the end walls 6 and 6 of the divided tank bodies 3A and 3B.
[0010]
A seal plate 14 and a finisher roller 23 are attached to one of the divided tank bodies 3A and 3B, and a partition wall 32 and a doctor 15 are attached to the other. A coating liquid supply port 38 is opened at the lower portion of the peripheral wall of the divided tank body 3A on the side supporting the finisher roller 23. A return liquid port 39 communicating with the return liquid chamber 31 is opened in the lower part of the peripheral wall of the divided tank body 3B on the side supporting the partition wall 32.
[0011]
The finisher roller 23 includes an outer roller 24 that circumscribes the coating roller 1, and an eccentric shaft 25 that moves the outer roller 24 toward and away from the coating roller 1. The outer roller 24 is a coating roller 1. Rotating with the rotational force of.
[0012]
As the coating roller 1, a gravure roller formed by forming a cell group for holding a coating liquid on the roller peripheral surface is used. The contact ends 15a and 14a of the doctor 15 and the seal plate 14 are in contact with the slightly lower side of the side top position of the peripheral surface of the coating roller 1 to seal the lower half side peripheral surface of the coating roller 1. It has stopped. The liquid level of the coating liquid in the coating liquid chamber 30 is set at a substantially intermediate position between the upper end of the partition wall 32 and the upper peripheral surface of the finisher roller 23.
[0013]
[Action]
A coating liquid chamber 30 for storing the coating liquid is provided inside the coating liquid tank 3. Separately, a return liquid chamber 31 is defined, and the excess coating liquid scraped off by the doctor 15 passes through the return liquid chamber 31. Therefore, the generation of bubbles due to the excess coating liquid can be prevented. However, when the peripheral surface of the rotating coating roller 1 is immersed again in the coating liquid, it cannot be prevented until ambient air is brought into the liquid. In this way, the finisher roller 23 is disposed in the coating liquid tank 3 in order to crush and remove the bubbles brought into the liquid or to force the coating liquid into the cells on the roller peripheral surface. The peripheral surface circumscribes the lower peripheral surface of the coating roller 1. The doctor 15 and the seal plate 14 circumscribe each peripheral surface of the coating roller 1 to prevent evaporation of the solvent in the coating liquid tank 3 and at the same time prevent entry of ambient air into the coating liquid chamber 30 as much as possible.
[0014]
According to the coating liquid tank 3 in which the pair of divided tank bodies 3A and 3B are connected so as to be swingable and openable by the shaft 4, the bolts and the like for fastening the divided surfaces of the divided tank bodies 3A and 3B are removed and then shown in FIG. Thus, the coating roller 1 can be easily detached from the coating liquid tank 3 by opening and swinging the divided tank bodies 3A and 3B while supporting the coating roller 1. At that time, in order to facilitate replacement of the coating roller 1, a bearing portion 12 is provided on the dividing surface of the end wall 6 of each divided tank body 3 </ b> A, 3 </ b> B, and the shaft portion of the coating roller 1 is formed by the pair of bearing portions 12. 11 can be held. Between the bearing portion 12 and the shaft portion 11, an airtight seal 13 and a bearing are mounted as shown in FIG.
[0015]
Since the finisher roller 23 and the partition wall 32 are respectively mounted on different divided tank bodies 3A and 3B, when the divided tank bodies 3A and 3B are disassembled, the finisher roller 23 and the partition wall 32 face the dividing surface. Therefore, maintenance work such as replacement and repair of both 23 and 32 can be easily performed.
[0016]
The finisher roller 23 composed of the outer roller 24 and the eccentric shaft 25 can displace the outer roller 24 by rotating the eccentric shaft 25. Therefore, when the application roller 1 having a different diameter is exchanged and mounted. However, the finisher roller 23 can be shared. The contact pressure of the outer roller 24 against the coating roller 1 can be changed according to the difference in the viscosity of the coating liquid.
[0017]
When the liquid level of the coating liquid is set at a substantially intermediate position between the upper end of the partition wall 32 and the upper peripheral surface of the finisher roller 23, the finisher roller 23 is completely submerged in the coating liquid. The liquid level of the coating liquid in the coating liquid tank 3 can be made as low as possible to reduce the remaining amount of coating liquid at the end of coating.
[0018]
【Example】
1 to 4 show an embodiment of a roll coater according to the present invention. In FIG. 2, reference numeral 1 is a coating roller, 2 is a rubber impression roller, and 3 is a sealed coating liquid tank. The web W is guided around the impression roller 2, and its lower surface is pressed against the top of the peripheral surface of the coating roller 1. The coating roller 1 is rotationally driven in the counterclockwise direction, and causes the coating liquid to adhere to the lower surface of the web W while feeding it in the direction of the arrow.
[0019]
The coating liquid tank 3 is composed of a bowl-shaped container whose upper surface is open, and the coating roller 1 and the coating liquid are accommodated therein. For convenience such as replacement or repair of the coating roller 1, the coating liquid tank 3 is composed of a pair of divided tank bodies 3A and 3B in the front and rear (web transport direction), and both tank bodies 3A and 3B are swung around the shaft 4. Connect to open and close. Specifically, the coating liquid tank 3 is composed of a pair of divided tank bodies 3A and 3B divided by a vertical plane passing through the central axis of the coating roller 1. As shown in FIG. 4, each of the divided tank bodies 3 </ b> A and 3 </ b> B includes a partially arcuate curved wall 5 along the peripheral surface of the coating roller 1, and a pair of left and right end walls 6 and 6 projecting from both ends of the curved wall 5. And a plurality of hinge bosses 7, 7 projecting along the joint surface at the lower end of the curved wall 5, and both tank bodies are formed by shafts 4 inserted through these bosses 7, 7. 3A and 3B are connected so as to be swingable and openable. Both ends of the shaft 4 are supported by bearings 9 provided on the machine base 8.
[0020]
3 and 4, the coating roller 1 is a gravure roller in which a group of cells are formed on the roller peripheral surface without a break, and a small-diameter shaft portion 11 protrudes from both ends thereof. The shaft 11 protrudes out of the tank through semicircular bearings 12 and 12 formed on the joint surfaces of the end walls 6 and 6 of the tanks 3A and 3B. An airtight holding seal 13 is mounted between the bearing portion 12 and the shaft portion 11. Although not shown, the coating roller 1 is supported rotatably by supporting both shaft portions 11 and 11 projecting out of the tank with bearings provided on the machine base 8, and the other shaft portion 11 is further supported by the machine. It is configured to be rotationally driven by a drive mechanism provided on the table 8.
[0021]
In the state accommodated in the coating liquid tank 3, the upper peripheral surface of the coating roller 1 protrudes upward from the upper surface opening of the coating liquid tank 3 as shown in FIGS. 1 and 2, and the top of the coating roller 1. Is in contact with the impression roller 2 via the web W. In order to seal the coating liquid tank 3 by closing the gap between the coating roller 1 and the coating liquid tank 3 in this state, a sealing plate 14 and a doctor 15 are provided on the upper part of the front and rear divided tank bodies 3A and 3B. It arrange | positions and the protrusion is circumscribed on the surrounding surface of the coating roller 1. FIG. The doctor 15 is disposed on the roller peripheral surface side coming out of the coating liquid, that is, on the upper side in the rotational direction of the coating roller 1 relative to the impression roller 2.
[0022]
The sealing plate 14 is made of a stainless steel plate having an appropriate thickness with the contact end 14a with the coating roller 1 being smoothly finished, and is inclined to the coating roller 1 so as to be in one split tank body 3A. Install. A side end seal 16 is provided separately from the seal plate 14 as shown in FIG. 3, thereby closing a gap between the coating roller 1 and the end wall 6. The side end seal 16 is also attached to the other divided tank body 3B.
[0023]
The doctor 15 is made of the same metal blade as the seal plate 14, is clamped and fixed to the mounting base 17 at the upper part of the divided tank body 3B, is inclined downward in the direction opposite to the seal plate 14, and its contact end 15a is a coating roller. It circumscribes the peripheral surface of 1. In order to adjust and change the contact pressure of the contact end 15 a to the coating roller 1, as shown in FIG. 1, as shown in FIG. The fixed arm 19 can be swung by an air cylinder 20 provided on the outer surface of the divided tank body 3B. In order to close the gap between the mounting base 17 and the divided tank body 3B, one end of the seal sheet 21 is fixed to the mounting base 17, and the other end side of the seal sheet 21 is brought into close contact with the inner peripheral surface of the divided tank body 3B. It is along. The seal sheet 21 is formed of a tetrafluoropolyethylene sheet.
[0024]
The seal plate 14 and the doctor 15 are in contact with the coating roller 1 at the positions where the respective contact ends 14a and 15a are shifted in the vertical center position of the roller peripheral surface, that is, 5 to 10 mm below the side top position. Set to This is to prevent the coating liquid scraped off by the doctor 15 from reattaching to the peripheral surface of the coating roller 1. Incidentally, when the coating liquid is reattached, the coating liquid film after scraping is uneven in density, and the density is transferred to the web W as it is.
[0025]
Thus, according to the coating liquid tank 3 sealed with the seal plate 14, the doctor 15 and the side end seal 16, the evaporation of the solvent contained in the coating liquid stored in the tank is prevented, and the air in the workplace is contaminated. Can be avoided as much as possible. In addition, the phase angle of the roller peripheral surface exposed to the air can be suppressed to a little over 180 degrees to prevent drying on the roller peripheral surface, and clogging of the cells can be avoided.
[0026]
Since a group of indented cells are exposed on the roller peripheral surface after coming into contact with the web W, air existing in the cells is easily brought into the coating liquid as the roller rotates, and bubbles are easily generated. . In order to forcibly remove such bubbles, the finisher roller 23 is disposed in the coating liquid, and its peripheral surface is pressed against the lower peripheral surface of the coating roller 1. The furnisher roller 23 is composed of an outer roller 24 whose peripheral surface that is in contact with the coating roller 1 is rubberized, and an eccentric shaft 25 that operates the outer roller 24 to contact and separate from the coating roller 1. The outer roller 24 receives the rotational force of the coating roller 1 and rotates along with it, forcibly removing air in the cell and bubbles adhering to the peripheral surface of the roller. As shown in FIG. 3, both ends of the eccentric shaft 25 are pivotally supported by the end wall 6 of the divided tank body 3A on the side attached to the seal plate 14, and the shaft ends protrude outside the tank. By swinging the protruding shaft portion 26 with an air cylinder 28 via an arm 27, the outer roller 24 can be operated to contact and separate from the coating roller 1, and the contact pressure can be changed to a larger or smaller value.
[0027]
In order to prevent the coating liquid from foaming due to the excess coating liquid scraped off by the doctor 15, the inside of the coating liquid tank 3 receives the excess coating liquid and returns to the coating liquid chamber 30 for storing the coating liquid. The return liquid chamber 31 is divided. Both the chambers 30 and 31 are divided by a partition wall 32 disposed inside the divided tank body 3B on the side where the doctor 15 is mounted. The partition wall 32 is made of a stainless steel plate having a partially arc-shaped cross section, and is arranged and fixed along the lower peripheral surface of the coating roller 1 between the finisher roller 23 and the doctor 15, and the upper end thereof is in contact with the doctor 15. It faces the vicinity of the end 15a. A flow guide wall 33 is provided at the upper end of the partition wall 32 by folding the plate surface toward the return liquid chamber 31. A gap having an appropriate size is secured between the partition wall 32 and the peripheral surface of the coating roller 1. This is to cope with a change in the diameter dimension of the coating roller 1.
[0028]
In FIG. 2, the coating liquid stored in the tank 35 is pressurized by the pump 36 and fed through the supply passage 37, and the coating liquid supply port 38 opened at the center of the lower peripheral wall of the one divided tank body 3 </ b> A. Is supplied into the coating liquid chamber 30. Further, the surplus coating liquid in the return liquid chamber 31 is returned to the previous tank 35 through a return passage 40 connected to a return liquid port 39 communicating with the lower part in the return liquid chamber 31. Reference numeral 41 denotes a supply passage for replenishing a new coating liquid.
[0029]
The liquid level of the coating liquid in the coating liquid chamber 30 is set below the upper end of the partition wall 32 and above the upper peripheral surface of the finisher roller 23. Preferably, the liquid level is set at a substantially intermediate position between the upper limit liquid level and the lower limit liquid level, so that the finisher roller 23 is reliably prevented from being exposed on the liquid surface, and the coating when the coating operation is completed is preferably performed. The coating liquid material in the liquid chamber 30 is reduced as much as possible. By reducing the remaining amount of the coating liquid in this way, the amount of the coating liquid discarded is reduced, the cost required for the disposal is reduced, and wasteful consumption of the coating liquid constituent material before adjustment is suppressed.
[0030]
In addition to the above embodiment, the coating liquid tank 3 can be divided forward and backward on a plane passing through the centers of the coating roller 1 and the finisher roller 23, and may be divided at other positions. The doctor 15 may be directly fixed to the divided tank body 3 </ b> B similarly to the seal plate 14. In this case, the doctor 15 having a different length is replaced and used in accordance with the change in the diameter dimension of the coating roller 1.
[0031]
The finisher roller 23 can be rotationally driven by a dedicated drive mechanism. In this case, the roller 23 is driven in the counterclockwise direction in the same manner as the coating roller 1. In the space between the divided tank body 3A and the coating roller 1, a nozzle for spraying and supplying the cleaning liquid is disposed, and the coating roller 1 is rotated while the coating liquid tank 3 is sealed. The coating material adhering to the peripheral surface can be washed away with the cleaning liquid ejected from the nozzle. The coating roller 1 may be a roller other than the gravure roller.
[0032]
【The invention's effect】
In the present invention, a return liquid chamber 31 is provided separately from the coating liquid chamber 30, and the excess coating liquid scraped off by the doctor 15 is received and returned by the return liquid chamber 31, and bubbles are generated by the dropping action of the excess coating liquid. To prevent it. Further, the finisher roller 23 is disposed in the coating liquid stored in the coating liquid chamber 30, and the peripheral surface thereof is pressed against the coating roller 1 to forcibly cause bubbles attached to the peripheral surface of the coating roller 1. It can be removed. Therefore, it is possible to stably and continuously produce a web coated with a coating liquid by eliminating coating defects due to foam adhesion.
[0033]
Since the coating tank 3 is composed of a pair of split tank bodies 3A and 3B that can swing open and close, the coating tank 1 can be applied by simply opening the split tank bodies 3A and 3B around the shaft 4 as required. It can be taken out from the tank 3. Thereby, also when using the coating roller 1 from which a diameter dimension, a width dimension, or a surrounding surface structure differs, the coating liquid tank 3 is shared and equipment cost can be reduced by that much.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of a coating liquid tank.
FIG. 2 is a longitudinal side view schematically showing a roll coater.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is a longitudinal side view conceptually illustrating the attaching / detaching operation of the coating roller.
FIG. 5 is a vertical side view of a conventional roll coater.
FIG. 6 is a side view conceptually illustrating another conventional roll coater.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Coating roller 2 Impression roller 3 Coating liquid tank 3A * 3B Division tank body 4 Shaft 11 Coating roller shaft 12 Bearing part 14 Sealing plate 15 Doctor 23 Finisher roller 30 Coating liquid chamber 31 Return liquid chamber 32 Partition wall 38 Coating liquid supply port 39 Return liquid port

Claims (3)

The coating roller (1) and the coating liquid are accommodated inside the coating liquid tank (3) whose upper surface is open, and the opening edge of the coating liquid tank (3) and the peripheral surface of the coating roller (1). The gap coater is a roll coater that is closed by the doctor (15) and the seal plate (14) circumscribing the peripheral surface of the coating roller (1),
Inside the coating liquid tank (3), a finisher roller (23) that circumscribes the lower peripheral surface of the coating roller (1) and forcibly removes air bubbles is disposed so as to be immersed in the coating liquid. And
A partition wall (32) is disposed along the lower peripheral surface of the coating roller (1) between the finisher roller (23) and the doctor (15), and the interior of the coating liquid tank (3) is the coating liquid. A chamber (30) and a return liquid chamber (31) that receives and recirculates the excess coating liquid scraped off by the doctor (15) ,
The coating liquid tank (3) is composed of a pair of divided tank bodies (3A and 3B) that are divided back and forth on a plane passing through the central axis of the coating roller 1.
Both divided tank bodies (3A, 3B) are connected so as to be able to swing open and close by a shaft (4) arranged on the outer surface of the peripheral wall, and the coating roller (1) can be exchanged and mounted in the open state.
Bearing parts (12, 12) for holding the shaft part (11) of the coating roller (1) are formed on the divided surfaces of the end walls (6, 6) of both divided tank bodies (3A, 3B). Yes,
A seal plate (14) and a finisher roller (23) are attached to one of the two divided tank bodies (3A, 3B), and a partition wall (32) and a doctor (15) are attached to the other,
A coating liquid supply port (38) is opened at the lower part of the peripheral wall of the divided tank body (3A) on the side supporting the finisher roller (23),
A return-type liquid port (39) communicating with the return liquid chamber (31) is opened in the lower part of the peripheral wall of the divided tank body (3B) on the side supporting the partition wall (32). Roll coater with a liquid tank. The finisher roller (23) includes an outer roller (24) that contacts the coating roller (1), and an eccentric shaft (25) that operates the outer roller (24) toward and away from the coating roller (1). comprise and, a roll coater outer roller (24) is provided with a coating liquid tank of the closed type receives a rotational force you rotate together claim 1, wherein the coating roller (1). The coating roller (1) is a gravure roller formed by forming a cell group for holding a coating liquid on the roller peripheral surface,
The contact ends (15a, 14a) of the doctor (15) and the seal plate (14) are respectively in contact with the coating roller (1) slightly below the side top position of the peripheral surface of the coating roller (1). 1) The lower half side peripheral surface is sealed,
Coating liquid chamber (30) liquid level of the coating liquid in the can and upper end of the partition wall (32), claim is set to a substantially intermediate position between the upper circumferential surface of the furnisher roller (23) 1 Or the roll coater provided with the sealing type coating liquid tank of 2 description .

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