JP2775167B2 - Coating device - Google Patents

Description

The present invention relates to a coating apparatus, in particular, a photographic film material, a photographic photosensitive material such as photographic paper, a photoengraving material, a magnetic recording material such as a magnetic recording tape, a pressure-sensitive material. The present invention relates to an improvement in an apparatus for applying a liquid coating composition (hereinafter, referred to as a coating liquid) for a continuously running long flexible support in the production of recording materials such as recording paper and heat-sensitive recording paper.

[Conventional technology]

2. Description of the Related Art Conventionally, as a device for applying a coating liquid onto a flexible support that is continuously supported and supported by a backup roller, a roller coating device, a dip coating device, a fountain coating device, an air knife coating device, a blade coating device,
There are an extrusion coating device, a bead coating device, a curtain coating device and the like. In this case, the backup roller plays a role of maintaining a constant distance between the supporter supported by the backup roller and the liquid injector, and has a large effect on the coating film thickness. In response to the recent increase in coating speed and thinner coating film thickness, this backup roller has been finished as a precise coating device and a precision ball bearing has been adopted as the bearing supporting the backup roller. ing.

[Problems to be solved by the invention]

However, in the application of photosensitive materials and recording materials, in particular, as shown in JP-B-33-8977 and JP-B-46-16830, the technology of simultaneously coating a very thin film of several micrometers in multiple layers has been developed. Due to the demand for higher product quality and production speed, the improvement of the accuracy of the distance between the backup roller and the liquid injector has come to play an important role. As one of them, that is, a backup roller using a roller bearing (ball bearing) as a bearing of a backup roller, which is one of the main parts of the coating apparatus, has seen a limitation in performance.

More specifically, minute vibrations caused by the rolling motion of the balls or rollers of the roller bearing excite the natural vibration of the backup roller, and appear as coating step unevenness as a result of coating. This phenomenon increases as the coating speed increases.

In addition, the roller bearing cannot prevent radial runout of the inner ring due to its structure. The guaranteed value is 5 even in the case of class 4 (super precision class SP class of the old standard) for a shaft diameter of 100 mm.
Although it is less than μm, no matter how much effort is made to manufacture the roller, it is necessary to prepare for a runout of 5 μm or more after assembly, including the runout of the roll itself. This results in a failure of color alignment unevenness in the case of a photographic light-sensitive material as a result of application of the product.

SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional problems and to provide a coating apparatus capable of high-speed thin layer coating without generating uneven coating steps and uneven color even when the coating speed is increased.

[Means for solving the problem]

The gist of the present invention resides in that a fluid bearing that does not generate vibration or radial runout from the bearing itself is used as the bearing supporting the backup roller.

That is, the object of the present invention is to provide an apparatus for applying a coating liquid from a liquid injector on a flexible support that is continuously supported and supported by a backup roller, wherein the backup roll is supported by a fluid journal bearing. This is achieved by a coating apparatus characterized in that:

The backup roller in the present invention is a roller that is used in a coating device, supports a continuously running flexible support, and performs coating on the flexible support. As the material of the shaft, alloy steel such as carbon steel for machine structure and Ni-Cr steel is used. Usually 100
It has a diameter of ~ 200mm and a length of 1000 ~ 3000mm.

The flexible support in the present invention includes paper, plastic film, resin coated paper, synthetic paper, and the like.
The material of the plastic film is, for example, a polyolefin such as polyethylene or polypropylene, a polyvinyl polymer such as polyvinyl acetate, polyvinyl chloride and polystyrene,
Polyamides such as 6,6-nylon and 6-nylon, polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, polycarbonates, cellulose acetates such as cellulose triacetate and cellulose diacetate are used. The resin used for the resin-coated paper is typically a polyolefin such as polyethylene, but is not necessarily limited to this. Further, as the metal flexible support, there is an aluminum plate or the like.

Further, the coating liquid in the present invention includes those having various liquid compositions depending on the application. For example, a coating solution such as a photosensitive emulsion layer, an undercoat layer, a protective layer and a back layer as in a photographic material; a magnetic layer, an undercoat layer, a lubricating layer, a protective layer and a back layer as in a magnetic recording medium , Etc. coating liquid;
Other examples include coating solutions such as an adhesive layer, a coloring layer, and a rust-preventive layer. These coating solutions contain a water-soluble binder or an organic binder.

The hydrodynamic bearing in the present invention is different from a sliding bearing, and refers to a hydrostatic or hydrostatic journal bearing having a small rotational friction and a hydraulic or hydraulic pressure.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

2 and 3 are a side sectional view (a) and a front sectional view (b) showing one embodiment of a fluid bearing of a backup roller used in the present invention.

The basic structure of the fluid bearing is, as shown in FIG. 3, provided inside the bearing 2 with an oil reservoir (pocket) 17 and a throttle valve 16 which are divided into several parts which communicate with an oil supply port 13, and on both sides thereof. The oil discharge groove 19 is adjacent to the journal 15 by a partition wall 18 having a suitable gap, and communicates with the oil discharge port 14. When the backup roller 1 is biased to one side by the action of the external force, the gap of the oil sump 17 on that side is narrowed and the oil pressure of the oil sump 17 rises, and the gap is widened on the opposite side and the oil pressure drops. A strong resistance force is immediately generated against the slight displacement of the journal 15 and the equilibrium position is maintained, so that the deviation of the axis of the backup roller is extremely small. Can be made as small as necessary by selecting the inner diameter of In the case of fluid bearings, the backup roller's shaft rotation accuracy is extremely good, the frictional resistance is low, the temperature rise is small, there is no seizure phenomenon, the backup roller is quiet, and there is no element that generates mechanical vibration. It has ideal performance as a bearing for automobiles.

[Action]

With the coating device in which the backup roller of the present invention is supported by a fluid journal bearing, the relative vibration between the backup roller and the liquid injector generates, in the case of a roller bearing, a vibration of 1 to 3 μm due to ball or roller roller movement. In contrast, in the case of fluid bearings, the shaft is supported by hydraulic pressure, so there is no element that causes vibration on the bearing itself, such as the roller and the roller's roller, compared to when the roller is rotating and when it is stopped. With a vibration of about 0.5 μm or 0.5 μm or less without any particular change, it becomes about 1/5 of the conventional vibration.

Therefore, this vibration, that is, the relative vibration between the backup roller and the liquid injector, appears as unevenness in the application step by vibrating the application liquid. However, the use of the fluid bearing significantly improves the step unevenness failure in the application quality. Can be done.

In addition, as for the run-out of the backup roll, the run-out of the roller itself is about 5 μm even when using a super-precision grade 100 mm ball bearing in the case of a roller bearing, whereas the run-out of the bearing itself is negligible in the case of a fluid bearing. Only the run-out of the backup roller itself appears as a whole,
μm, which is 1/5 to 1/3 that of the conventional bearing, which is very good.

This fluctuation appears as color unevenness in one rotation cycle of the backup roller in terms of coating quality of the photosensitive material, but the effect of adopting the fluid bearing in this aspect is great.

In addition, by using a fluid bearing, the bearing stiffness of the fluid bearing can be increased as compared with other bearings, and the displacement of the backup roller can be reduced with respect to a change in external force at the same bearing span.

Further, the roller bearing needs lubrication, but the fluid bearing is supported by hydraulic pressure and has no abrasion and can be used semi-permanently without fear of seizure, which is advantageous for maintenance and inspection.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to this embodiment, and can be applied to any application apparatus using a backup roller.

As shown in FIG. 1, the coating apparatus of the present invention is an apparatus for applying a coating liquid using a liquid injector 4 on a flexible support 3 continuously supported and supported by a backup roller 1. As shown in FIG. 2, the bearings at both ends of the backup roller 1 are supported by fluid journal bearings 2a and 2b, and photographic photosensitive is applied to a continuously running flexible support 3 using a liquid injector 4 for a multi-layer simultaneous coating apparatus. The coating liquids 5, 6, 7, 8 of the material are applied.

As shown in FIG. 3, pressure fluid is applied to the fluid bearings 2a and 2b from the oil supply port 13 in the direction of the arrow, enters a plurality of oil reservoirs 17 through the throttle valve 16, and supports the backup roller 1 with the pressure fluid. Axis.

This pressure fluid passes through a small gap between the partition wall 18 and the journal 15 of the backup roller 1 and flows into the annular discharge grooves 19 arranged on both sides of the oil reservoir, and is collected by the oil discharge port 14 and discharged in the direction of the arrow. Is done.

A hydraulic pressure of 20 kg / cm ² is applied from the oil supply port 13 of each of the fluid bearings 2a and 2b to the support on the backup roller 1 to 100 to 300 m / m
As a result of performing the application at the transport speed of n, the vibration of the backup roller 1 becomes 0.5 μm, which is about 1/5 of the conventional vibration of the roller bearing of 1 to 3 μm, and the vibration of the backup roller 1 becomes 1 to 5. 3 μm, which was reduced to about 1/3 to 1/5 of about 5 μm of the runout of the conventional roller bearing.

〔The invention's effect〕

As is clear from the above, the application device of the present invention makes the vibration and deflection of the backup roller extremely 1/3 to 1/5 of the conventional one.
As a result, even if the coating speed becomes high, unevenness of the coating step and color unevenness do not occur, the quality of the coated product is improved, and a high-speed thin-layer coating can be performed, which greatly contributes.

[Brief description of the drawings]

FIG. 1 is a side view of an embodiment of a coating apparatus employing a fluid bearing as a bearing of a backup roller of the present invention, FIG. 2 is a front view of an embodiment in which a fluid bearing is applied to the backup roller of the present invention, FIG. 3 is a side view (a) and a front view (b) of a schematic sectional view of one embodiment of a fluid bearing of the present invention. DESCRIPTION OF SYMBOLS 1 ... Backup roller 2, 2a, 2b ... Bearing 3 ... Flexible support 4, Liquid injector 5, 6, 7, 8 ... Coating liquid 13 ... Oil supply port 14 ... Drainage of oil Outlet 15: Journal, 16: Throttle valve 17: Oil reservoir (pocket), 18: Partition wall 19: Oil discharge groove

Claims (1)

(57) [Claims] 1. An apparatus for applying an application liquid from a liquid injector onto a flexible support that is continuously supported and supported by a backup roller, wherein the backup roller is supported by a fluid journal bearing. Coating equipment.