JPH0223359A - Development processing method for photosensitive planographic printing plate - Google Patents

Abstract

PURPOSE:To prevent the generation of a trouble in case of a development processing and stains at the time of processing by sticking a magnetic material to the printing plate having a nonmagnetic base and transporting and processing the printing plate by using an automatic developing machine equipped with a transporting belt having magnetic force. CONSTITUTION:The developing machine has a developing section 1, a washing section 2, the transporting belt 4 having magnetic force, shower pipes 5a, 5b, a developing soln. tank 6, a developing soln. pump 7, a rotary brush 8, a washing water tank 2, a washing water pump 13, squeezer rollers 9, 15. The photosensitive planographic printing plate 3 under transportation by the transporting belt 4 is fixed to the transporting belt 4 by the attraction force of the magnetic material stuck to the rear surface thereof and the transporting belt 4 having magnetic force and is thereby transported and developed. The developed plate is washed in the washing section 2. The generation of the stains on the plate surface at the time of the development processing and the trouble in transportation is prevented in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for developing a photosensitive lithographic printing plate, and more particularly to a conveyance means for developing a photosensitive lithographic printing plate using an automatic processor.

[Background of the invention]

When developing a large number of exposed photosensitive lithographic printing plates, an automatic developing machine is generally used. The mode of developing a photosensitive lithographic printing plate with an automatic developing machine is to convey the photosensitive lithographic printing plate horizontally with the photosensitive layer facing up using a conveyor roller or a conveyor belt, while showering a developer onto the photosensitive layer. A method is known in which the photosensitive layer is supplied by an appropriate method and developed by rubbing the photosensitive layer with a brush or the like.

When a photosensitive lithographic printing plate is transported by a transport roller, it is necessary to provide a roller on the upper side and press it with the roller to prevent meandering, etc. There is a drawback that the upper roller is stained by the developer containing the component, and this smudge is transferred to the photosensitive lithographic printing plate, resulting in staining on the finished plate. Is it possible to avoid stains on the plate caused by the upper roller by using belt conveyance?
In this case as well, there is a drawback that the photosensitive planographic printing plate meanderes during transportation or is turned over by a brush.

Japanese Unexamined Patent Publication No. 63-23161 describes a device in which a photosensitive printing plate having a magnetic support is washed using a brush, in which the photosensitive printing plate is fixed by attraction and conveyed by a conveyor belt having a magnetic force. Disclosed is an apparatus that performs the following operations. However, this is not effective if the support is made of a non-magnetic material, and non-magnetic materials are often lighter in weight, which tends to cause problems during transportation as described above.

[Purpose of the invention]

An object of the present invention is to improve photosensitive lithographic printing which can solve problems such as meandering or turning over when developing a photosensitive lithographic printing plate using a non-magnetic material such as an aluminum plate or a resin plate as a support. An object of the present invention is to provide a method for developing a plate.

Another object of the present invention is to provide a method for developing a photosensitive lithographic printing plate, which improves the staining of the lithographic printing plate obtained after the development process.

[Structure of the invention]

The above-mentioned object of the present invention is to attach a magnetic substance to at least a part of a photosensitive planographic printing plate having a non-magnetic support and to transport the plate using an automatic developing machine which is transported by a transport belt having a magnetic force. This is achieved by a method for developing a photosensitive lithographic printing plate, which is characterized by processing.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a side sectional view showing an example of an apparatus used in the development processing method of the present invention. In the figure, 1 is a developing section, 2 is a washing section, and 3 is an exposed photosensitive lithographic printing plate being transported, the back surface (the lower surface in the figure) of which has a magnetic material adhered to it. Reference numeral 4 denotes a conveyor belt having a magnetic force for conveying the exposed photosensitive planographic printing plate 3, and is driven by a motor.

As this conveyor belt 4, an endless rubber magnetic seat belt, a magnetic metal seat belt, etc. can be used.

5a and 5b are shower vibes that supply the developer to the surface of the photosensitive planographic printing plate 3; 6 is a developer tank that contains the developer; 7 is a pump that conveys the developer from the developer tank 6 to the shower vibe 5as5b; A rotating brush 9 rubs the surface of the photosensitive planographic printing plate 2 to accelerate development, and 9 is a squeeze roller for removing deposits from the surface of the photosensitive planographic printing plate.

In the washing section 2, 11 is a shower nob for supplying washing water to the surface of the photosensitive lithographic printing plate, 12 is a washing water tank for storing washing water, and 13 is a shower pipe for discharging the washing water in the washing water tank 12. Pump for sending to vibe 11, 14
1 is a pair of transport rollers for transporting a photosensitive planographic printing plate;
5 is a squeeze roller.

The exposed photosensitive lithographic printing plate is inserted and transported from the left end of the diagram with the photosensitive layer to be developed facing up. First, the transport system is driven by an inlet switch (not shown), and at the same time the developer is turned on. The developer in the tank 6 is pumped by the pump 7 and is jetted out from the shower nozzles 5a and 5b.

The photosensitive lithographic printing plate 3 being conveyed by the conveyor belt 4 is fixed to the conveyor belt 4 and conveyed by the attraction force between the magnetic material attached to the back surface of the plate and the magnetically charged conveyor belt 4 .

The developer jetted out from the shower nozzle 5a is uniformly supplied to the surface of the photosensitive planographic printing plate 3, and the surface to which the developer was supplied is rubbed with a rotating brush, and then the developer is sprayed through the shower nozzle 5b.
After being developed with a developer supplied from the developer, the squeeze roller 9 removes the deposits on the surface. Photosensitive planographic printing plate 3
is then conveyed to the washing section 2. In the washing section, washing water is supplied from a shower nozzle 11 for washing, and water on the surface is removed by a squeeze nozzle 15. The pump 13 is operated in conjunction with the drive of the conveyance system.

Representative examples of the nonmagnetic support included in the photosensitive lithographic printing plate according to the present invention include an aluminum plate and a resin plate. In addition, as a photosensitive lithographic printing plate, an aluminum plate is used as a support, and a photosensitive layer whose solubility in a developing solution changes when exposed to light is coated on it, and the photosensitive layer in non-image areas is removed by development. Typical examples include those from which a lithographic printing plate is obtained.

In the present invention, a magnetic substance is attached to at least a portion of the side (back side) of the photosensitive planographic printing plate that is not to be developed. As a specific means, for example, a method such as attaching a magnetic tape or a magnetic plate, or applying a magnetic paint can be used.

As a means for pasting the magnetic material, it is preferable to use a magnetic tape with one side of which is adhesive, since it simplifies the work of adhering and removing the magnetic material from the photosensitive planographic printing plate.

In addition, there is a method of imparting magnetism by coating the back side of an exposed photosensitive lithographic printing plate with a paint containing a magnetic material dispersed therein.

The magnetic tape may cover the entire back surface of the photosensitive lithographic printing plate, but it is sufficient to cover a portion thereof, specifically, usually about 1 to 15% of the area of the back surface. A preferred mode of adhesion of the magnetic tape is shown in FIG. In the figure,
3 is a photosensitive planographic printing plate, and 20 is a magnetic tape.

As mentioned above, the development processing method in which the surface of the photosensitive planographic printing plate being conveyed on the conveyor belt is rubbed with a brush is a problem that occurs during conveyance, where the photosensitive planographic printing plate may meander or turn over due to friction caused by the plan. Although troubles are likely to occur,
The present invention solves such troubles. Therefore, the present invention is particularly effective in an embodiment in which the surface of a photosensitive planographic printing plate is rubbed with a brush on a conveyor belt.

As for the mode of rubbing with a brush, as in the case of the rotating brush 8 in FIG. Examples include methods in which the surface is rubbed by reciprocating motion, and methods in which a brush roller is rotated to rub the circumferential surface of a roller whose rotation is parallel to the rotational axis of the belt wheel of the conveyor belt. The optimum conditions for brushing and scrubbing vary depending on the photosensitive lithographic printing plate, the type of developer, the developing temperature, etc., so it is difficult to generalize, but the former is usually used when the bristles of the brush are made of nylon and the bristles are thin. Length 10-40mm.

Rotating brush diameter 50-200mm, rotation speed 40-60
0rpm.

The speed of the reciprocating motion is preferably in the range of 0.5 to 1.5 m/sec.

The latter has nylon bristles and a bristly length of 10 to 30 cm.
11 The diameter of the brush roller is preferably 40 to 150 II 1 m, and the number of rotations for rubbing is preferably in the range of 30 to 180 rpm.

In the present invention, it is preferable that the surface of the magnetic conveyor belt, that is, the surface that comes into contact with the photosensitive planographic printing plate, has minute depressions capable of retaining the developer. An example of a preferable recess is a groove with a U-shaped cross section (depth 0.5~
1.0+am, lji 0.5-1.0+++o, interval 05-1.5+on) in the conveying direction and/or in a direction perpendicular to the conveying direction.

By providing such minute indentations, the developer is retained on the conveyor belt, and a sufficient amount of developer is retained on the photosensitive layer at the peripheral edge of the photosensitive lithographic printing plate. This solves the problem of insufficient development.

[Example] As a developing device, an apparatus of the embodiment shown in FIG. 1 was used. A developer having the following composition was prepared and placed in the developer tank 6 shown in FIG. 1, and the temperature of the developer was adjusted to 27°C.

Developer solution Potassium silicate aqueous solution (Si (h/20 molar ratio 1.0.
5i02 concentration 2% by weight)...
10kg Perex NBL (sodium alkylnaphthalene sulfonate, manufactured by Kako Atlas Co., Ltd.)...5k
g water
...10kg50%KOH p)l to 1
It was adjusted to 2.85.

On the other hand, SMP-N (product name, positive type 25 plate, manufactured by Konica Corporation) was used as a photosensitive planographic printing plate, and after image exposure, magnetic tape was pasted at two places on the back side as shown in Figure 2. The film was developed for 30 seconds using the automatic developing device shown in Figure 1. As a result, the printing plate was able to be developed well without meandering at very low speeds, and without the printing plate turning over and breaking due to the rotating brush.

For comparison, when photosensitive lithographic printing plates were treated in the same manner without applying magnetic tape to the back side, the plates meandered or were turned over by the brush, resulting in creases in the plates.

〔Effect of the invention〕

The present invention provides a development processing method for photosensitive planographic printing plates having a non-magnetic support, which improves stains on the surface of the planographic printing plate after development and troubles during transportation.

[Brief explanation of the drawing]

FIG. 1 is a sectional side view showing an example of a development processing apparatus for carrying out the method of the present invention, and FIG. 2 is a plan view showing a mode of attaching a magnetic substance to a photosensitive planographic printing plate. l...Developing section 2...Water washing section 3...Photosensitive lithographic printing plate 4...Transport belt 5a, 5b...Shower pipe 6...Developer tank 7.13...Pump 8 ... Rotating brush 9 ... Squeeze roller 20 ... Magnetic tape

Claims (1)

[Claims] A photosensitive method characterized in that a magnetic substance is attached to at least a portion of a photosensitive lithographic printing plate having a non-magnetic support, and the plate is transported and processed using an automatic developing machine that is transported by a conveyor belt that has a magnetic force. A method for developing a lithographic printing plate.