JPH066345Y2 - Web coating refrigerator - Google Patents

Description

[Detailed Description of the Invention] (A) Field of Industrial Use The present invention is a cooling device for cooling a fluidized coating layer to gel it in the step of drying after coating a photographic emulsion layer or the like on a web. The present invention relates to a transport roller arranged inside the apparatus.

(B) Prior art and its problems In general, the photosensitive emulsion layer coated on the web is in a fluid state before gelling.

In the past, while the undried web was conveyed by a large number of conveying rollers, cold air was blown to the surface of the photosensitive emulsion layer to cool the emulsion by heat transfer and heat of vaporization on the surface of the emulsion layer to cause gelation. However, in this method, if the interval between the transport rollers is narrowed, the contact between the web and the transport rollers deteriorates, which causes scratches on the back surface of the web. Therefore, the interval between the transport rollers needs to be wide. Therefore, wrinkles may occur on the web depending on the transport tension,
In addition, since a strong wind cannot be applied to the photosensitive coating layer in a fluidized state, a long conveying system path having a low cooling efficiency is required.

In order to solve this, by cooling the transport rollers while sucking and transporting them from a number of transport rollers arranged in close proximity, the web is cooled by contact heat conduction between the web and the transport rollers. How to gel the emulsion layer,
As shown in Japanese Utility Model Publication No. 56-41802, a ventilation port is provided at a position distant from the surface of one side of the conveyance rollers arranged in close proximity to each other, and a decompression exhaust port is provided on the opposite side to the ventilation side of the conveyance rollers. It is publicly known that a cooling device or the like characterized by meandering and transporting a web in the front and back directions of a web while contacting the web has been considered.

However, since the transport roller in the cooling device is generally made of metal such as stainless steel or aluminum, it has large thermal expansion with respect to temperature. Due to the thermal expansion of the transport rollers arranged close to each other, the transport rollers may come into contact with each other or the guides of the transport rollers may come into contact with each other, resulting in poor rotation and scratches on the back surface of the web. was there.

The above problem can be solved by designing the thermal expansion into a small size in advance, but conversely, when the temperature is low, the distance between the transport rollers and the distance between the roller and the guide become wider, so that the suction efficiency from the roller side is increased. The slippage occurs between the web and the transport roller, causing scratches on the back surface of the web.

In the design of the device, it is designed so that it is in the most preferable state at the temperature usually used, so the machine cannot operate unless it is below a certain temperature, or when changing the set temperature in the cooling device, This requires replacement of the transport rollers and position change, which has been a cause of reducing the productivity of the machine.

(C) Purpose of the invention The purpose of the invention is to eliminate the above-mentioned drawbacks, and even when the set temperature in the device is changed, it is not necessary to replace the transfer roller or change the position, and the web is scratched. The object is to provide an excellent cooling device that does not allow it.

(D) Configuration of device The object of the present invention is to have a linear expansion coefficient as a conveying roller in a cooling device for gelating a coating layer in a fluidized state in the process of drying a gelatin-containing coating liquid applied on a web. 5 x 10
^{The present} invention has been achieved by providing a cooling device for a coating layer of a web, which uses a conveying roller made of a material having a low thermal expansion coefficient of ⁻⁶ / deg or less.

Generally, iron, which is often used as the material of the transport roller,
The linear expansion coefficients of stainless steel and aluminum are
12 x 10 ^-6 / deg, 17 to 18 x 10 ^-6 / deg 23 x 10 ^-6 /
It is about deg. Examples of the material of the conveying roller used in the present invention include carbon molded ceramics, glass and the like. However, as long as the linear expansion coefficient is 5 × 10 ⁻⁶ / deg or less, the material is not limited to these. Absent. Also,
The surface of these materials may be subjected to a surface treatment such as plating, a surface treatment such as cutting or sandblasting, and then used.

(E) Embodiment Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a side sectional view of a cooling device of the present invention, and FIG. 2 is a plan view. Reference numeral 1 is a web, 2 is a conveying roller, 3 is a depressurizing device of a type in which suction is performed by a fan (not shown), and 4 is a guide for attaching the conveying roller.

Dry-bulb temperature in the cooling device is 0 ~ 10 ℃, web speed is 120
m / min, transport tension 15 kg / width, decompression device decompression 300 mm H20
Then, a gelatin-containing coating liquid was applied to a polyethylene film having a width of 1200 mm and a thickness of 100 μm and conveyed. The material of the transport roller was aluminum, stainless steel, and a carbon molded product.

When the temperature in the cooling device was 0 to 5 ° C., no difference was found regardless of which material the transport roller was used. Next, when the temperature in the cooling device is set to 6 to 10 ° C., in the case of the aluminum and stainless steel conveying rollers, the conveying rollers come into contact with each other at point A in FIG. The guide contacted at point B in FIG. 2 and rotation failure of the transport roller occurred. This resulted in scratches on the back surface of the web, which is thought to be the cause.

On the other hand, when the carbon molded product carrying roller was used, the above problems did not occur, the carrying roller rotated smoothly, and the web could be carried without being scratched.

(F) Effect of the Invention According to the present invention, it is possible to arrange the conveying rollers in a preferable state regardless of the temperature inside the apparatus and prevent the web from being scratched. Further, even when the machine starts to operate, it is not necessary to wait for the machine to operate until the temperature inside the device has dropped, and the machine can be operated efficiently.

These make it possible to make a machine with high productivity.

[Brief description of drawings]

FIG. 1 is a side sectional view of a cooling device showing an embodiment of the present invention,
FIG. 2 is a plan view. 1 ... Web, 2 ... Conveyor roller 3 ... Pressure reducing device, 4 ... Conveyor roller mounting guide

Claims (1)

[Scope of utility model registration request] 1. A linear expansion coefficient of 5 × 10 ⁻⁶ as a conveying roller in a cooling device for gelating a coating layer in a fluidized state in the step of drying a gelatin-containing coating liquid applied on a web.
A cooling device for a coating layer of a web, which uses a conveying roller made of a material having a low thermal expansion coefficient of less than / deg.