JPH03126035A - Photosensitive planographic printing plate material and plate making method thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photosensitive lithographic printing plate material and a plate-making method thereof.

[Prior art and its problems]

Conventional planographic printing plates that have been put into practical use include a 28 plate having a photosensitive resin layer on an aluminum support, a printing plate having a silver salt photosensitive layer, and a printing plate having an electrophotographic photosensitive layer.

Although the 28 plate has high printing durability, it has the drawbacks of low sensitivity and high cost because it requires a large amount of film as an intermediate document. Silver salt printing plates have high sensitivity and are suitable for direct plate making, but cannot be said to be sufficient in terms of printing durability.

Today, argon laser, helium neon laser,
A scanning exposure direct plate making method using a laser light source such as a laser diode as a light source has been developed, but the printing durability is still not sufficient.

A silver halide emulsion layer is provided on the photosensitive resin layer of the 28th plate,
Photosensitive lithographic printing plate materials are known that use a silver image formed in an emulsion layer as a mask for plate making, but they have drawbacks such as insufficient image reproducibility and difficulty in manufacturing. Since it is not compatible with output machines, it is necessary to develop a special output machine.

(Object of the Invention) An object of the present invention is to provide a photosensitive lithographic printing plate material and a plate-making method thereof, which allow plate-making of a lithographic printing plate having high resolution and high printing durability by a scanning exposure method.

[Structure of the invention]

The above object of the present invention is achieved by a photosensitive lithographic printing plate material characterized in that it has a photosensitive resin layer and a physical development nucleus layer in sequence on an aluminum support.

Further, the above-mentioned object of the present invention is to bring the scan-exposed silver halide photographic light-sensitive material and the light-sensitive lithographic printing plate material into close contact and perform complex salt diffusion transfer development, and then transfer the transferred silver image to a photosensitive resin layer using the transferred silver image as a mask. This is achieved by a plate-making method characterized by exposing the photosensitive resin layer to light and developing the photosensitive resin layer.

The present invention will be explained in more detail below.

The support used in the photosensitive lithographic printing plate material of the present invention is
Preferably, aluminum or an alloy mainly composed of aluminum is subjected to surface hydrophilic treatment such as anodizing or graining.

There are various kinds of photosensitive resins that can be provided on an aluminum support, and they are classified into photo-insolubilizable photosensitive materials and photo-solubilizable photosensitive materials. Photo-insolubilizable photosensitive materials include dichromic acid colloids, diazo resins (for example, condensates of diazodiphenylamine and formaldehyde), photopolymers (photodimerizable types such as polyvinyl cinnamate, and polyfunctional vinyl monomers). Polymerization type) etc. The photo-solubilizable photosensitive material is a positive-working photosensitive layer in which exposed areas are photodecomposed and become soluble in a developer, and orthoquinonediazide is used therein.

The physical development nucleus layer provided on the photosensitive resin layer is used as an image-receiving material for the silver complex diffusion transfer method, and is made by coating physical development nuclei of heavy metals or their sulfides dispersed in a binder such as gelatin. It is. The physical development nucleation layer is preferably uncured or only slightly cured to allow eventual wash-off.

In order to carry out the plate-making method using the photosensitive lithographic printing plate material of the present invention, it is necessary to use a conventional scanning exposure photosensitive material, that is, a support such as resin-coated paper or film, and optically enhance it by adjusting the wavelength of the light source. A photosensitive material having at least a sensitive silver halide emulsion layer is scanned and exposed, and this is brought into close contact with the photosensitive lithographic printing plate material of the present invention, and conventional silver complex salt diffusion transfer development is performed. After peeling off both materials, using the transferred silver image (generally having a transmission optical density of about 3 or more, preferably about 4 or more) as a mask, the photosensitive resin layer is imaged by full-surface exposure with ultraviolet light. exposed to light. Next, the photosensitive resin layer is developed using a PS plate developer containing sodium silicate, etc. At this time, most of the physical development nucleus layer is also removed, but if necessary, it is necessary to wash it further after development. - You may perform off processing.

The lithographic printing plate made in this manner can be subjected to printing processing and printing by a well-known method, and can enable printing with extremely high resolution and high printing durability.

Examples are shown below.

〔Example〕

On a commercially available 28 plate (having a photosensitive resin layer on an aluminum support), an aqueous gelatin solution containing palladium sulfide as physical development nuclei was applied with a doctor so that the gelatin Ig/n (gelatin Ig/n) was formed, and dried. did.

On the other hand, a light-sensitive material having a silver halide emulsion layer sensitive to argon laser light on a polyester film support was subjected to scanning exposure using an argon laser output device.

Both of the above materials were brought into close contact through a processor containing a developer for silver complex diffusion transfer, and peeled off after 1 minute. A highly clear, high-density silver image was formed on the physical development nucleus layer.

Next, using this silver image as a mask, the entire surface of the 28th plate was exposed using a machine and developed with a commercially available developer for PS plates. All physical development nuclei were washed off.

When printing was performed using the obtained lithographic printing plate, more than 100,000 extremely clear prints could be made.

〔Effect of the invention〕

According to the present invention, a photosensitive lithographic printing plate material with high resolution and high printing durability can be easily manufactured, and an image scanned and exposed using an existing output device can be printed by a simple plate-making operation. Since it can be used as an image, it is also economically advantageous.

Claims (2)

[Claims] (1) A photosensitive lithographic printing plate material characterized by having a photosensitive resin layer and a physical development nucleus layer sequentially on an aluminum support. (2) A photosensitive lithographic printing plate material having a photosensitive resin layer and a physical development nucleus layer sequentially on an aluminum support and a scanningly exposed silver halide photographic light-sensitive material are brought into close contact and silver complex salt diffusion transfer development is performed. A plate-making method characterized by performing exposure using a transferred silver image as a mask to form a photosensitive resin layer.