JPS6227862B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of coating and forming a resin layer in a resin gravure cylinder and an apparatus therefor.

Generally, resin gravure cylinders are created by coating the surface of a cylindrical substrate with a photosensitive resin liquid such as polyamide at a uniform thickness, drying, smoothing the surface of the resin layer, and then baking and developing a pattern. be done.

By the way, the surface of a gravure cylinder is required to have a high degree of smoothness, but when the plate surface is made of resin, even higher precision is required because the resin has high ink receptivity. Ru. Such smoothness can be obtained by highly polishing the layer surface. However, this polishing operation requires a considerable amount of effort and time, and since a large amount of resin must be applied in anticipation of the polishing amount, a large amount of expensive resin liquid is consumed.

Therefore, in order to eliminate the above-mentioned drawbacks, it is better to devise a coating process so that the resin layer is coated and formed as uniformly as possible from the beginning.

Methods for applying the resin liquid onto the surface of the substrate include a spray method, a brush coating method, a dipping method, a vertical coating method, a knife blade coding method, and the like. Among these, there is a technique disclosed in Japanese Patent Application Laid-Open No. 51-21903 that attempts to apply and form a resin layer using a knife blade coating method.
According to this coating technique, the resin layer can be coated with a relatively satisfactory uniform thickness.

However, since this prior art uses a metal knife blade, it has various drawbacks.

Some large cylindrical substrates are eccentric by several tens of microns. In order to apply resin liquid to the surface of such a substrate, coating must be started by placing a knife blade at the closest point with a gap of 20 to 30 μm, but at the farthest point there is a gap of 70 to 30 μm. 80
It also becomes μ. Therefore, it becomes necessary to increase the viscosity of the resin liquid to prevent problems such as dripping of the resin liquid at the farthest contact portion.

However, when the viscosity of the resin liquid is increased, the resin layer is dried with each rotation of the substrate, so a step of 20 to 30 μm or 70 to 80 μm clearly appears at the beginning of the coating film from the beginning, reducing the final film thickness by 50 μm. In the case of gravure finished to ~500μ, preferably 100 to 200μ, this step will remain until the coating is completed.

This means that the above-mentioned long polishing process is required and extra resin liquid is required.

However, even if the knife blade is brought closer to the substrate surface and the gap at the fastest contact point is reduced, the knife blade will come into contact with the substrate at the closest point, resulting in damage to the substrate surface or the knife blade. I end up. The cutting damage accumulates in the gap between the knife blade and the substrate and damages the surface of the resin layer during the coating process.

The same can be said of the normal substrate without eccentricity.

The present invention has been developed in view of the above circumstances, and includes a knife blade that is brought into contact with the substrate surface from the start of coating to prevent a step from forming at the beginning of the coating film.
Even if the viscosity of the resin liquid is set low, problems such as dripping will not occur, and at the same time, neither the knife blade nor the base will be damaged.

That is, the present invention provides the following features: a. A photosensitive resin liquid is spirally applied to the surface of a cylindrical substrate, and the application is performed so that drying of the coating liquid is substantially completed each time the substrate rotates once.

(b) The coating is performed by a knife blade coating method, and the knife blade is imparted with elasticity and at least its tip is made softer than the surface of the substrate.

c. The application should begin with the tip of the knife blade in contact with the substrate surface.

d) The above application is performed by gradually moving the knife blade away from the substrate surface as the substrate rotates.

A method for forming a resin layer of a resin gravure cylinder consisting of: a) means for horizontally supporting a cylindrical base and rotating it at a constant speed;

b. A resin layer drying device installed opposite to the cylindrical substrate.

c. A knife blade which is imparted with elasticity and whose tip is made softer than the base surface.

d a rotating arm that holds the knife blade and brings the knife blade into contact with the substrate surface;

e Pressure means for elastically applying force to the rotating arm toward the contact position between the base body and the knife blade.

f A cam that rotates the rotating arm in a direction opposite to the force as the base rotates.

The gist of this invention is an apparatus for coating and forming a resin layer of a resin gravure cylinder.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a resin layer coating and forming apparatus that employs a knife blade coating method.

In the figure, 10 is a machine frame of the apparatus, and a cylindrical base body 12 is horizontally supported on the upper part of the machine frame. The base body 12 is rotated at a constant speed by a prime mover 14 equipped with a reduction gear and a transmission mechanism using gears, wheels, belts, chains, etc. Further, a drying device 16 is installed so as to partially cover the cylindrical substrate. The drying device is preferably a far infrared radiation heater 1
It has 8 built-in. Far infrared rays effectively diffuse and evaporate the solvent of the resin liquid applied to the surface of the cylindrical substrate.
This is because air bubbles are not generated inside.

A knife blade 20 is installed on the opposite side of the drying device across the cylindrical substrate. The knife blade is held by a rotating arm 22 extending upward from within the machine frame.

Two rotating arms 22 are provided on both sides in the axial direction of the base body, and the lower part thereof is supported by a shaft 24, so that the rotating arm 22 can rotate about the pivot point 24. The length of the rotating arm 22 is set so as to draw a large arc that moves the knife blade 20 almost horizontally. Rotating arm 22
is elastically pressed toward the contact position between the base body 12 and the knife blade 20 to allow the knife blade to perform a smooth coating action. Specifically, this pressurizing action is performed by the weight 26. A stopper 28 is provided on the opposite side of the weight.

The weight causes the knife blade to be in constant contact with the substrate surface. However, as the base 12 rotates and the coating of the resin liquid 30 progresses, the knife blade 20 must be moved away from the base surface, so a means for this purpose is provided in the middle of the rotating arm 22. Specifically, it is constituted by a cam 32. The cam 32 is attached to a prime mover 34 with a reduction gear installed in the machine frame 10. cam 3
A follower 36 for contacting the rotary arm 2 is installed on the rotating arm.

Since the rotation of the base 12 and the movement of the knife blade 20 are related, either the prime mover 14 or the prime mover 34 may be omitted and the base body 12 and the knife blade 20 may be driven by a single prime mover. good.

The prime mover 34 is placed on a pedestal 36,
By turning the screw 38 with a handle 40, it can be moved horizontally. As a result, even if base bodies with different diameters are installed in the apparatus, the knife blade 20 can be brought into contact with the surface of the base body by rotating the rotating arm 22.

Here, the knife blade 20 is given elasticity so as to make good contact with the base body, and at least its tip is made softer than the base surface so as not to damage each other with the base body surface. If the base body 10 is made of metal, the tip of the metal blade is covered with a synthetic resin layer 42, as shown in FIG. Alternatively, the knife blade 20 itself is composed of a single synthetic resin. In this case, the synthetic resin is filled with resin liquid 3
0, and has alcohol resistance, and also has heat resistance, in view of the fact that the substrate is heated and the resin liquid is heated during application.

Further, the knife blade 20 is supported by a support body 44, and the support body 44 is connected to the long hole 46 of the rotary arm 22.
The guide member 50 is slidably held by a guide member 50 which can be secured with a screw 48 to the guide member 50 .

A micrometer 52 is provided at the end of the guide member 50. Micrometer spindle 54
is fitted on the rear end of the support, so that the support 44 and the knife blade 20 are adjusted in position by the spindle 54 of this micrometer. Then, if necessary, it is fixed with screws 56. Two micrometers 52 are provided on both sides of the knife blade 20 in the length direction.

Knife blade 20 is fixed to support 44 with screws 58. The screws 58 are arranged vertically to face each other, and a large number of pairs are arranged at equal intervals in the length direction of the knife blade 20.

Additionally, in FIG. 1, reference numeral 60 is a roll whose surface is highly smoothed and is held by the rotating arm 22. The surface of the resin layer applied by this roll 60 is better smoothed. However, this roll is provided as necessary.

Next, the operation of the present invention will be explained. First, the surface of the base body 12 is degreased, and then the machine frame 10
installed on top. Next, the screw 38 is turned to adjust the position of the cam 32 so that the tip of the knife blade 20 comes into contact with the surface of the base depending on the diameter of the base. Further, if necessary, the micrometer 52 is operated before or after this to finely adjust the position of the tip of the knife blade 20 and more accurately adjust the positional relationship with the substrate surface. This adjustment is beneficial when the shaft of the base 12 is eccentric or twisted relative to the centerline of the base. By doing this, it is possible to build up the resin layer so as to absorb eccentricity, twisting, etc.

When the above adjustment is completed, the resin liquid 30 is filled onto the knife blade 20. Then, the heater 18 is turned on and the base body 12 is rotated.

By doing so, the application of the resin liquid 30 is started, but at this time, the knife blade 20 is in elastic contact with the base 12 due to the action of the weight 26, and since the blade 20 is soft, the application of the resin liquid 30 is started. There is no step at the starting end 62 of the resin liquid, and the resin liquid 30
will be applied extremely smoothly.

After this, the tip of the knife blade 20 gradually moves away from the base surface due to the action of the cam 32, and the resin liquid 3
0 is applied over and over in a spiral pattern to form a resin layer of the desired thickness. The coating of the resin liquid 30 is carried out by irradiation with far infrared rays so that the drying of the coating liquid is completed in good quality every time the base 12 rotates once, so that problems such as the formation of bubbles inside the layer do not occur.

The substrate on which the resin layer has been coated is then polished to smooth the surface, and then a pattern is printed and developed to form a gravure printing plate.

Now, since the present invention has the above-mentioned structure and operation, the resin liquid can be uniformly applied so that no steps or drips occur, regardless of the level of viscosity of the resin liquid. be able to. Therefore, it is possible to simplify and speed up the subsequent smoothing work such as the polishing process, and to minimize the consumption of expensive resin liquid.
Moreover, since reducing the amount of polishing leads to reducing the amount of frictional heat generated, it is possible to prevent as much as possible the deterioration of the original shape and sensitivity of the resin layer due to heat.

Example The cylindrical base is a metal cylinder with a circumference of 628 mm and a length of 700 mm, the knife blade is a metal blade with a 100μ thick polyester film attached to the tip, and the metal cylinder is heated at 3 to 5 rpm.
Rotate the blade at a constant speed within the range of 5 to 30μ/
The resin liquid was applied while separating within the range of min.

The resin liquid is 400 parts by weight of a methyl alcohol solution containing 20% photosensitive polyamide resin (trade name Topron, manufactured by Tokyo Ohka Kogyo Co., Ltd.), 100 parts by weight of methyl alcohol.
Made by weight part, viscosity is 10~400CPS at 25℃ or
I set it to 40-100CPS.

When a photosensitive resin layer was formed with a thickness of 100 to 200μ in the above manner, the surface accuracy was extremely excellent, with no steps, undulations, or craters, and the polishing process could be completed with a minimum thickness of about 10μ. Ta.

[Brief explanation of the drawing]

FIG. 1 is a front view of an example of a coating device according to the present invention, and FIG. 2 is an enlarged view of the knife blade portion thereof. 12... Cylindrical substrate, 16... Drying device, 20
...Knife blade, 22...Rotating arm, 26...
Weight, 30... Photosensitive resin liquid, 32... Cam, 42
... Synthetic resin layer, 62 ... Starting end of coating resin liquid.

Claims (1)

[Scope of Claims] 1. Method a for forming a resin layer of a resin gravure cylinder comprising the following: A photosensitive resin liquid is applied spirally onto the surface of a cylindrical substrate, and the application is applied every time the substrate rotates once. Apply so that the liquid is substantially dry. (b) The coating is performed by a knife blade coating method, and the knife blade is imparted with elasticity and at least its tip is made softer than the surface of the substrate. c. The application should begin with the tip of the knife blade in contact with the substrate surface. d) The above application is performed by gradually moving the knife blade away from the substrate surface as the substrate rotates. 2 Apparatus for coating and forming a resin layer of a resin gravure cylinder consisting of the following items: a Means for horizontally supporting a cylindrical base and rotating it at a constant speed. b. A resin layer drying device installed opposite to the cylindrical substrate. c. A knife blade which is imparted with elasticity and whose tip is made softer than the base surface. d a rotating arm that holds the knife blade and brings the knife blade into contact with the substrate surface; e Pressure means for elastically applying force to the rotating arm toward the contact position between the base body and the knife blade. f A cam that rotates the rotating arm in a direction opposite to the force as the base rotates.