Fuji Photo Film Company, Limited

Kei Okuno

Nobuyuki Kita

Ikuo Kawauchi

Tatsuji Higashi

Yoshihiko Urabe

Koichiro Aono

A quality control method for a planographic printing plate having disposed on a substrate a photosensitive layer formed by a resin soluble in an aqueous alkali solution and a compound that absorbs light to generate heat, the quality control method having the steps of: (A) exposing, to an ultraviolet ray, a gray scale for evaluating a positive type planographic printing plate made by exposure to an ultraviolet ray, followed by development with a standard developing solution having a standard formula, and measurement of the sensitivity of the gray scale processed by the standard developing solution; (B) exposing, to an ultraviolet ray, a gray scale for evaluating a positive type planographic printing plate made by exposure to an ultraviolet ray in the same manner as in the step (A), followed by development with a developing solution to be evaluated, and measurement of the sensitivity of the gray scale processed by the developing solution to be evaluated; (C) comparing the sensitivity of the gray scale processed by the developing solution to be evaluated with the sensitivity of the gray scale processed by the standard developing solution; and (D) adjusting exposure/development conditions when the difference between the sensitivities exceeds a predetermined value as a result of the comparison of the sensitivity of the gray scale processed by the developing solution to be evaluated with the sensitivity of the gray scale processed by the standard developing solution.

Quality control method for a planographic printing plate

A dry PS plate comprises a substrate having provided thereon in order a primer layer, a light-sensitive layer and a silicone rubber layer wherein the primer layer comprises a film forming polyurethane resin and a diazonium salt polycondensate. The dry PS plate is excellent in the adhesion strength between the substrate and the light-sensitive layer. The adhesion is surely maintained even after imagewise exposure to light and the subsequent development. The dry PS plate shows excellent image reproduction and the resulting dry lithographic plate is excellent in printing durability as well as resistance to scratch.

PS plate for use in making lithographic printing plate requiring no

The present invention relates to a presensitized plate for use in making a lithographic plate requiring no dampening water and comprising, on a support, a light-sensitive resin layer and a silicone rubber layer, in this order, wherein the silicone rubber layer is crosslinked by addition reaction of an .fwdarw.SiH group with a --CH.dbd.CH-- group and wherein the light-sensitive resin layer comprises: (1) a monomer or oligomer having at least one photopolymerizable or photo-crosslinkable and olefinically unsaturated double bond, (2) an organic solvent-soluble polyurethane resin having a glass transition temperature of 20.degree. C. or below and being capable of forming a film, and (3) a photopolymerization initiator. According to the present invention, the PS plate has excellent image-forming properties and printing properties.

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Shizuoka, Japan

Kei Okuno