JP2002346468A - Painting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of suppressing quality defects such as a deformation and damage of web since a predetermined shape having a relatively high top can be obtained when a web after being coated is wound in a roll state. SOLUTION: An outer diameter distribution in a roll width direction of an uncoated roll wound in a roll state prepared from an uncoated web 25 is first measured with an outer diameter measuring device 18 and a measured outside diameter distribution data is inputted to a computer 20. The computer 20 compares the measured outside diameter distribution of the uncoated roll and that of a coated roll with a preset outside diameter distribution to calculate the difference between the outside diameter distributions before and after painting and operates a coating thickness distribution in the width direction of a web to be applied onto the web 25 so as to remove the difference between the outside diameter distributions thereof. Furthermore, the computer 20 automatically controls a plurality of slit adjusting means 14 through an actuator 16 so as to allow a gap quantity distribution in the web width direction of a slit 30 in a coating head 12 to be a gap quantity distribution to perform coating in a required coating thickness quantity distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a coating method,
In particular, the present invention relates to an improvement in a coating method for producing a photographic photosensitive material or a magnetic recording medium.

[0002]

2. Description of the Related Art Photosensitive materials and magnetic recording media are manufactured through a coating process of forming a coating film by coating a predetermined coating solution on a continuously running belt-like support (hereinafter referred to as "web"). . In particular, magnetic recording media such as magnetic recording tape
In recent years, the capacity and recording density have been rapidly improved for broadcasting and computers, and a coating technique capable of obtaining a magnetic layer having an extremely thin film thickness and a smooth surface has been required.

[0003] As a method of applying a coating solution on a web surface, for example, there are a roll coater method, a gravure coating method, a roll coating plus doctor method, an extrusion type coating method, a slide coating type coating method and the like. Extrusion-type coating methods are frequently used for applying a magnetic coating solution. In this extrusion type coating method, the coating liquid is extruded from the slit tip of the coating head and applied to the web while the continuous running web and the tip of the coating head are pressed relatively to each other. Since a layer can be obtained, the recording capacity can be remarkably improved.

[0004] For example, in the case of manufacturing a magnetic recording tape, the coated web is subjected to necessary processing such as calendering and curing by heating, and then cut into a predetermined width. The product is wound around a shaft in the (cassette case). In addition, as processing before cutting, it is general that after each processing is performed, as shown in FIG. 8, once wound into a roll, and then sent to the next step.

[0005] In this winding operation, if the air entrained together with the web (hereinafter referred to as "entrained air") is not efficiently removed, the winding may be misaligned at the time of winding.
The tape may be deformed due to the accumulated air during the curing process, which causes a reduction in product yield.

As a method for eliminating the entrained air, there is a method of suppressing entrained air entrainment by lowering the running speed of the web and slowly winding the web, but this significantly reduces the productivity. There is also a method of removing the entrained air by increasing the winding tension at the time of winding, but there is a drawback such that the web surface is damaged when the winding tension is increased.

As a countermeasure against these problems, as shown in FIGS. 8 and 9, a roll having a roll whose outer diameter is uneven in the axial direction of the roll (solid line in FIGS. 8 and 9) is replaced with a roll. A so-called middle-high shape (a broken line in FIGS. 8 and 9) in which the center portion is high and both end portions of the roll is low, whereby the entrained air is efficiently discharged from the center portion of the roll toward the end portion. Japanese Patent Application Laid-Open No.
In Japanese Patent Application Laid-Open No. 1-293577, the thickness distribution of the coating in the web width direction is 1.5 to 1 at the center of the roll rather than at both ends of the roll.
A coating method of coating so as to be 0% thicker is disclosed.

[0008]

By the way, the magnetic recording tape can be wound as long as possible per cassette half to increase the recording capacity per one roll. It is getting thinner. Further, when a non-magnetic lower layer and a magnetic upper layer are formed on a web, the thickness of the non-magnetic lower layer as well as the magnetic upper layer tends to be reduced. On the other hand, high-density magnetic recording tapes require high-quality products without tape deformation and tape scratches.

Under such severe demands for thinner webs and coating layers and higher quality, Japanese Unexamined Patent Publication No.
Even if the method disclosed in Japanese Patent No. 293577 is carried out, there is a disadvantage that a clean middle and high shape for eliminating entrained air cannot be obtained at the time of winding the web.

[0010] The present invention has been made in view of such circumstances, and when the support after application is wound into a roll,
An object of the present invention is to provide a coating method capable of suppressing a quality failure such as deformation of a support or damage to the support, because a predetermined middle-high shape can be obtained.

[0011]

According to the present invention, in order to achieve the above object, one or a plurality of coating liquids are applied to the surface of a continuously running belt-like support to form a coating film on the support. In the method, for the total thickness distribution obtained by adding the thickness distribution in the width direction of the support thickness and the thickness distribution in the support width direction in the dry film thickness of the coating film, the central portion in the support width direction is an end portion. The distribution of the coating thickness in the width direction of the support applied to the support is adjusted so as to be 1.5 to 10% thicker than the above.

The present invention is not merely to make the thickness distribution in the width direction of the support in the dry film thickness of the coating film 1.5 to 10% thicker in the center in the width direction of the support than in the end portions. The thickness distribution in the width direction of the support applied to the support is adjusted in consideration of the thickness distribution in the width direction of the thickness of the support. Accordingly, when the support after application is wound into a roll, a predetermined middle and high shape can be obtained, and thus the entrained air can be effectively eliminated. Therefore, quality failures such as deformation of the support after application and damage to the support can be suppressed.

That is, the thinner the support, the more difficult it is to produce a support having a uniform thickness distribution, and the thinner the coating layer, the greater the influence of the thickness distribution of the support on the support after coating. It easily affects the shape of the roll peripheral surface when wound into a roll. However, according to the coating method of the present invention, it is possible to produce a photographic photosensitive material or a magnetic recording medium that sufficiently satisfies the demands of thinner supports and coating layers and higher quality products.

In the adjustment of the coating thickness distribution, when a plurality of coating solutions are applied to the support to form a multilayer coating film, it is preferable to adjust the coating thickness distribution of the coating layer having the largest dry film thickness. . When two layers, a non-magnetic lower layer and a magnetic upper layer, are formed on the support, it is preferable to adjust the coating thickness distribution of the non-magnetic lower layer.

As an embodiment for carrying out the coating method of the present invention, first, an outer diameter distribution in a roll width direction of a roll before coating in which a support before coating is wound in a roll shape is measured. The measurement of the outer diameter distribution indirectly measures the thickness distribution of the thickness of the support in the width direction, and it is also possible to adopt a method of directly measuring the thickness distribution of the running support. However, since the present invention is to make the roll after application into a predetermined middle-high shape, it is more rational to measure the outer diameter distribution of the roll before application, and it is possible to easily measure it.

Next, the measured outer diameter distribution of the pre-coating roll is compared with a preset outer diameter distribution set beforehand for the post-coating roll in which the support after application of the coating solution is wound into a roll. Calculate the difference. The thickness distribution in the width direction of the support to be applied to the support is determined from the difference in the outer diameter distribution in consideration of the thickness distribution in the width direction of the thickness of the support.

Then, the thickness distribution of the coating applied to the support in the width direction of the support is adjusted so as to eliminate the calculated difference in the outer diameter distribution. Accordingly, when the support after application is wound into a roll, a predetermined middle and high shape can be obtained, and thus the entrained air can be effectively eliminated. Therefore, quality failures such as deformation of the support after application and damage to the support can be suppressed.

As a method of adjusting the thickness distribution of the coating liquid, the coating liquid is extruded from the slit tip of the coating head and coated on the web in a state where the continuously running support and the tip of the coating head are relatively pressed. An extrusion type coating apparatus is used, and slit adjusting means for adjusting the gap amount of the slit is at least 3 mm in the width direction of the coating head.
It is preferable to have at least one. Then, the slit adjustment means adjusts the slit gap amount distribution in the support width direction to correspond to the coating thickness distribution. In this case, it is possible to manually adjust the slit adjusting means,
It is preferable to perform automatic control by an actuator that drives the slit adjusting means and a computer that sends a control signal to the actuator.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the coating method according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of a coating apparatus to which the coating method of the present invention is applied.

As shown in FIG. 1, the coating apparatus 10 mainly comprises an extrusion type coating head 12, a slit adjusting means 14 for adjusting a slit gap amount of the coating head 12, and an actuator for driving the slit adjusting means 14. 16, an outer diameter distribution measuring device 18 for measuring the outer diameter distribution of the roll in the roll width direction, and a computer 20 for driving the actuator 16 based on the measurement result of the outer diameter distribution measuring device 18.

FIGS. 2 and 3 are explanatory views for explaining the coating head 12 and the slit adjusting means 14. FIG.

As shown in these figures, as shown in FIG.
Has a manifold 24 connected to a coating liquid supply port 22 (see FIG. 2) therein.
5 (see FIG. 3). Further, by assembling the blocks of the back edge 26 and the doctor edge 28 which make the coating head 12 dividable, a slit 30 for discharging the coating liquid over the width direction of the manifold 24 is formed. Further, the left and right ends and the center of the outer wall of the doctor edge 28 are provided with slit adjusting means 14, 14, 1 respectively.
4 are provided.

The slit adjusting means 14 mainly includes a yoke 32 and a biasing screw 3 attached to the yoke 32.
4, a fulcrum screw 37 and a fixing screw 38. As shown in FIG. 3, the yoke 32 is mounted so as to protrude from the outer wall surface of the doctor edge 28, and is fixed to the doctor edge 28 by a fixing screw 38 at an operation portion 39 closest to the distal end portion 36 of the coating head 12. Also, the tip 3
The urging portion 40 furthest from 6 is provided with an urging screw 34, and a fulcrum portion 41 at an intermediate position between the action portion 39 and the urging portion 40 is supported by the fulcrum screw 37. Then, the opening width t of the slit 5 is adjusted by adjusting the screwing amount of the urging screw 34 into the doctor edge 28 and applying a force to the action portion 39. For example, when the screwing amount of the urging screw 34 is adjusted and the urging unit 40 is operated so as to approach the outer wall surface of the doctor edge 28 (in the direction of arrow A), the fulcrum 41
And the lever in the direction of arrow B is applied to the action portion 39. Therefore, the doctor edge 28
The portion near the tip is pulled in the direction of arrow B, and accordingly, the tip portion 36 moves in the direction corresponding to the direction of arrow B (the direction of arrow C). As a result, the opening width t of the slit 30 is increased. Therefore, the slit adjusting means 1 provided at the left and right ends and the center of the outer wall surface of the doctor edge 28, respectively.
The gap amount distribution in the slit width direction (same as the web width direction) can be adjusted by adjusting each of the four. Any actuator can be used as the actuator 16 of the slit adjusting means 14 as long as the urging screw 34 can be rotated to adjust the screwing amount by a small amount.

FIG. 4 is an explanatory diagram for explaining the overall configuration of the outer diameter distribution measuring device 18, and FIG. 5 is an explanatory diagram for explaining displacement amount detecting means of the outer diameter distribution measuring device 18.

As shown in FIG. 4, the outer diameter distribution measuring device 18
Is mainly in the casing 44 whose bottom is open,
The roll 46 includes a displacement detector 48 for measuring the displacement of the roll 46 in the diameter direction and a moving unit 50 for moving the displacement detector 48 from one end to the other end in the roll width direction. When measuring the outer diameter distribution of, the casing 44 is detachably mounted on the roll 46 by the mounting jigs 47, 47.

As shown in FIG. 5, the displacement detecting means 48 is attached to the distal ends of the two arms 56 of the substantially V-shaped clamping means 54 whose base ends are connected by hinges 52, respectively. The sensor unit 58 and the reference point unit 60 are mounted so as to face each other. The sandwiching means 54 can be opened and closed in the AB direction in FIG. 5, and sandwiches the radial direction of the roll 46 wound around the core 62 between the sensor section 58 and the reference point section 60. The holding means 54 is provided with a fixing member (not shown) for fixing the open / close of the two arms 56, 56, and is fixed in a predetermined open / close state. The sensor unit 58 is provided with a C-
The reference point portion 60 is configured to be displaceable in the D direction (radial direction).
The relative displacement of the sensor unit 58 with respect to is measured. This displacement is expressed as a change in the outer diameter of the roll 46. As the sensor unit 58, for example, a differential transformer can be used.

As the moving means 50, when the outer diameter distribution measuring device 18 is installed on the roll 46, a rail 68 arranged parallel to the axial direction 71 of the roll 46, and a self-propelled power mounted on the rail 68 And a moving body 70 that moves
A so-called monorail system can be used. The connecting member 72 attached to the base end of the displacement measuring means 48 is connected to the moving body 70. Accordingly, the displacement amount detecting means 48 can move between one end and the other end of the roll 46 in the roll width direction. Accordingly, the sensor unit 58 associated with the movement of the displacement amount detecting unit 48 from one end in the width direction of the roll 46 to the other end by the moving unit 50.
Is measured as the amount of change in the roll diameter at each position in the roll width direction, that is, the outer diameter distribution. Note that the outer diameter distribution measuring device 18 is not limited to the contact type outer diameter distribution measuring device 18 in which the above-mentioned sensor contacts the object to be measured, but is a non-contact type outer diameter measuring device such as a laser displacement meter. The diameter distribution measuring device 18 may be used.

The computer 20, as shown in FIG.
The outer diameter distribution data of the roll 46 measured by the outer diameter distribution measuring device 18 is input by a signal cable or wirelessly, and a control signal of a slit gap amount to be adjusted by each slit adjusting means 14 is controlled by a signal cable or wirelessly. 16 is output. In addition, the computer 20 is input in advance with a set outer diameter distribution for forming a desired middle-high shape with respect to the peripheral surface shape of the roll 46, and a relationship between the outer diameter distribution difference obtained by a test or the like and the slit gap amount. ing.

Next, the coating apparatus 10 configured as described above
The coating method of the present invention will be described with reference to FIG.

First, the outer diameter distribution in the roll width direction of a pre-coating roll obtained by winding the web 25 before coating into a roll is measured by the outer diameter distribution measuring device 18, and the measured outer diameter distribution data is stored in a computer 20. Is input to

The computer 20 calculates the outer diameter distribution difference by comparing the measured outer diameter distribution of the pre-applying roll with the preset outer diameter distribution set for the post-applying roll, and calculates the outer diameter distribution difference so as to eliminate the outer diameter distribution difference. 25, the distribution of the coating thickness in the width direction of the web to be coated is determined. In this way, the application thickness distribution in the web width direction to be applied to the web 25 is determined in consideration of the thickness distribution of the web thickness in the width direction. Then, the computer 20 automatically controls the plurality of slit adjusting means 14 via the actuator 16 so that the gap amount distribution of the slits 30 of the coating head 12 becomes the gap amount distribution for applying the obtained coating thickness distribution. I do.

As described above, since the slit adjustment of the coating head 12 is completed, the web 25 is continuously run to apply the coating liquid. Thus, when the coated web 25 is wound into a roll, a predetermined middle-high shape can be obtained, so that the entrained air can be efficiently eliminated. Therefore, when the roll is heat-treated after application, the web 25 is not deformed due to the staying air. Also, since it is possible to obtain a predetermined middle-high shape, there is no need to increase the winding tension more than necessary to eliminate entrained air,
The web 25 is not damaged during winding.

In particular, the coating method of the present invention can form a clean middle and high profile even under severe conditions where it is difficult to obtain a predetermined middle and high profile such as thinning of the web 25 and the coating layer. FIG. 6 shows a case where an extremely thin web having a thickness of 4 to 6 μm (normal thickness is about 10 to 15 μm) is used to apply a coating solution by the coating method of the conventional Japanese Patent Application Laid-Open No. 61-293577. Shows the case where the coating liquid was applied by the coating method of the present invention.

Curves A in FIGS. 6 and 7 show the outer diameter distribution of the roll before coating. In the case of an extremely thin web, it is difficult to produce a uniform thickness web, so the thickness distribution is large. Curve B in FIG. 6 shows the outer diameter distribution of the roll after coating the web coated with the coating liquid by the conventional coating method, and curve C in FIG. 7 shows the coating in the present invention. This is the outer diameter distribution of the rear roll.

As can be seen from a comparison between FIGS. 6 and 7, in the conventional coating method, the thickness distribution of the web itself has a large effect on the outer diameter distribution of the roll after coating, whereas the coating method of the present invention does not. After the application, the roll can form a clean mountain shape.

In this case, with respect to the total thickness distribution obtained by adding the thickness distribution in the width direction of the web thickness and the thickness distribution in the web width direction in the dry film thickness of the coating film, the central portion in the web width direction is more than one end portion. The distribution of the coating thickness in the web width direction to be applied to the web may be adjusted so as to be 0.5 to 10% thicker.
The entangled shape thus formed can efficiently remove the entrained air during winding.

[0038]

According to the coating method of the present invention, when the support after application is wound into a roll, a predetermined middle and high shape can be obtained, so that the support is deformed or Quality failures such as scratching can be suppressed. In particular, a photographic photosensitive material or a magnetic recording medium that sufficiently satisfies the demands can be manufactured even under the strict requirements of thinner supports and coating layers and higher quality products.

[Brief description of the drawings]

FIG. 1 is a block diagram of a coating apparatus to which a coating method of the present invention is applied.

FIG. 2 is an explanatory view of a coating head and slit adjusting means.

FIG. 3 is an explanatory view for explaining the operation of a slit adjusting means.

FIG. 4 is an explanatory view for explaining the overall configuration of the outer diameter distribution measuring device.

FIG. 5 is an explanatory diagram for explaining a displacement amount detecting means of the outer diameter distribution measuring device.

FIG. 6 is an explanatory diagram illustrating a roller outer diameter distribution in a conventional coating method.

FIG. 7 is an explanatory diagram illustrating a roller outer diameter distribution in the coating method of the present invention.

FIG. 8 is an explanatory diagram illustrating a roll shape.

FIG. 9 is an explanatory diagram illustrating a roll outer diameter distribution.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Coating device, 12 ... Coating head, 14 ... Slit adjustment means, 16 ... Actuator, 18 ... Outer diameter distribution measuring device, 20 ... Computer, 24 ... Manifold, 25 ...
Web, 30 slit, 32 yoke, 34 urging screw, 36 tip, 37 fulcrum screw, 38 fixing screw,
39 ... action part, 40 ... urging part, 41 ... fulcrum part, 44 ...
Casing, 46 roll, 48 displacement detecting means, 5
0: moving means, 52: hinge, 54: pinching means, 56
... Arm, 58. Sensor part, 60. Reference point part, 62. Core, 68. Rail, 70. Moving body.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hideaki Takekuma 1-2-1 Ogimachi, Odawara-shi, Kanagawa Prefecture F-Film Co., Ltd. F-term (reference) 2H023 EA01 4D075 BB92X CA47 DA04 DC27 5D006 BA19 EA01 FA00 5D112 AA01 AA22 CC01 CC08 CC10 JJ01

Claims (1)

[Claims] 1. A coating method in which one or a plurality of coating liquids are applied to the surface of a continuously running belt-shaped support to form a coating film on the support, wherein a thickness distribution of the thickness of the support in a width direction is provided. With respect to the total thickness distribution obtained by adding the thickness distribution in the width direction of the support to the dry film thickness of the coating film, the support is formed such that the center in the width direction of the support is 1.5 to 10% thicker than the end. A coating thickness distribution in a width direction of a support to be coated on the substrate.