JPS6156505B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plate-making method using a liquid photosensitive resin composition (hereinafter referred to as "liquid composition").

Conventional plate-making methods using liquid compositions have been carried out by injecting the liquid composition between plates with spacers interposed therebetween, but the operations are complicated and it is difficult to make plates continuously. Additionally, a method has been proposed in which the liquid composition is supplied to the plate and spread with a doctor at the same time, that is, a method using a device in which a part of the container for supplying the liquid composition to the plate is a doctor, but it is difficult to smooth the plate. There were deficiencies in this respect.

As a result of intensive research to overcome the drawbacks of such conventional methods, the inventor of the present invention has discovered that it is possible to apply a liquid composition as needed without supplying the liquid composition in small amounts and spreading it with a doctor as in the conventional method. After supplying a certain amount of the liquid composition onto the printing plate at once, it is spread with a blade, and a separately supplied base sheet is spread on the spread surface, whereby the liquid composition and the base sheet are spread. It was discovered that a plate material having a uniform thickness and excellent smoothness can be obtained without introducing air bubbles or impurities, and based on this knowledge, the present invention was completed.

That is, the present invention provides a plate making method in which a liquid photosensitive resin composition is uniformly spread on a plate surface and a base sheet is spread, in which a doctor for spreading is arranged and a doctor is placed on the side opposite to the liquid supply side of the doctor. A cylindrical or cylindrical rotating roll is attached near the lower end with a predetermined gap between the doctor's surface and the rotating roll surface, a base sheet is inserted into the gap, and the end of the base sheet is inserted into the gap. The composition is fixed to the edge of the printing plate, and the necessary amount of the composition is first supplied onto the printing plate at once, and then the composition is spread uniformly on the printing plate by moving the doctor or by moving the printing plate. At the same time, the present invention provides a method characterized in that a base sheet supplied from the gap between the surface of the doctor and the surface of the rotating roll is spread on the surface of the spread liquid composition.

The printing plate used in the present invention is mainly made by adhering a negative film and a cover sheet to a transparent support such as a glass plate, and the liquid composition and base sheet are those used in conventional printing plates.

The plate making method according to the present invention, particularly the method of spreading a liquid composition onto the plate surface, will be explained based on the attached drawings.
The step of spreading the liquid composition onto the printing plate in the present invention consists of a step of supplying the liquid composition onto the printing plate and a step of spreading the supplied liquid composition to a uniform thickness, and these steps are performed individually. It is independent.

First, as for the method of supplying the liquid composition onto the printing plate, for example, a semi-cylindrical container 2 containing the liquid composition 1 as shown in FIG. .

The shape of the container 2 may be a half-square cylinder, but a semi-cylindrical shape allows the liquid composition to fall and be supplied more smoothly. In addition, other methods of supplying include manually applying each time using a method such as a sieve, or using a curtain flow coater.

In either case, it is preferable that the liquid composition is spread over the entire width of the printing plate in the direction perpendicular to the direction in which it travels.

Furthermore, after supplying the liquid composition, the container 2 may be left rotating, but it must not come into contact with the supplied liquid composition 1 on the printing plate.

When a semi-cylindrical container 2 is used, a scraping plate 4 is provided in contact with the inner wall of the container in order to facilitate supply to the printing plate and reduce loss of the liquid composition. This is particularly desirable.

Next, the liquid composition 1 thus supplied onto the printing plate is spread by a doctor 5 to a uniform thickness. That is, as shown in FIG. 2, by moving the doctor 5, the liquid composition 1 on the surface of the printing plate 3 can be spread to a uniform thickness on the printing plate.

In this case, the movement of the doctor 5 is carried out by fixing the printing plate 3 and moving the doctor 5, or conversely by fixing the doctor 5 and moving the printing plate 3.

The thickness of the flow film of the liquid composition can be adjusted to any desired thickness by adjusting the distance between the lower end surface of the doctor and the plate surface.

In the present invention, the liquid composition is spread to a uniform thickness on the printing plate through this step, and
This is not done in the previous step of supplying the liquid composition to the printing plate.

A base sheet is spread on the surface of the liquid composition thus spread to a uniform thickness.

In the method of the present invention, it is necessary to spread the liquid composition to a uniform thickness with a doctor and simultaneously spread the base sheet via a rotating roll provided at the lower end of the doctor. By doing so, the smoothness is greatly improved, and at the same time, air bubbles and impurities are prevented from being mixed in between the surface on which the liquid composition is spread and the base sheet.

That is, as shown in FIG.
A cylindrical or cylindrical rotating roll 6 is provided near the lower end of the printing plate, and a base sheet 7 is inserted into this in advance, and the base sheet 7 is fixed to the edge 8 of the printing plate. When the doctor or printing plate is moved, the rotary roll 6 rotates in synchrony with the movement, thereby automatically spreading the base sheet 7 on the surface of the spread liquid composition. In this case, after the base sheet 7 has adhered to the surface of the uniformly spread liquid composition to some extent, the base sheet fixed to the edge of the printing plate is removed from the edge. In order to obtain a uniform plate material, it is preferable that the distance between the lower end surface of the rotary roll 6 and the plate surface be the same as that between the lower end surface of the doctor, or slightly narrower.

When the former method is used, the liquid composition supply container 2, the doctor 5, and the rotating roll 6 can be integrated, and the rotating roll 6 is automatically rotated by the movement of the doctor or the printing plate. Therefore, there is no need for a special power source for rotation, which is economically advantageous, and the operation is extremely simple.

The latter method of spreading the base sheet involves spreading the liquid composition to a uniform thickness using a doctor, and then rotating a separately provided rotating roll. This method involves spreading the composition on the surface.

According to the method of the present invention, a printing plate can be manufactured with a simple operation and with good smoothness.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are explanatory diagrams of the plate-making method according to the present invention. 1: liquid composition, 2: supply container, 3: printing plate,
4: Kakitori board, 5: Doctor, 6: Rotating roll, 7: Base sheet, 8: Edge of printing plate.

Claims (1)

[Claims] 1. In a plate making method in which a liquid photosensitive resin composition is uniformly spread on a plate surface and a base sheet is spread, a doctor for spreading is arranged and a doctor is placed near the lower end of the doctor on the opposite side from the liquid supply side. , a cylindrical or cylindrical rotating roll is installed with a predetermined gap between the doctor surface and the rotating roll surface, a base sheet is inserted into the gap, and the end of the base sheet is attached to the edge of the printing plate. First, the necessary amount of the composition is supplied onto the plate surface at once, and then the composition is spread uniformly on the plate surface by moving the doctor or by moving the plate, and at the same time, the composition is spread on the surface of the doctor. A method characterized by spreading a base sheet supplied from a gap between the rotating roll surface and the surface of the spread liquid composition.