| 摘要 |
PURPOSE:To allow development with an aq. soln. contg. silicate of high pH without generating the sludge of a photocrosslinkable polymer by forming the above-mentioned polymer of a specific polymer which is soluble or swellable in alkaline water. CONSTITUTION:The acid value of the photocrosslinkable polymer is confined to 50 to 200, the weight average mol. wt. thereof to 5,000 to 100,000 and the glass transition temp. to <=50 deg.C in the case of developing the photosensitive planographic printing plate having a negative type photosensitive layer contg. the photocrosslinkable polymer and sensitizer on a base with the aq. soln. which contains substantially no org. solvent and contains the silicate of >= pH 12. The development is executed without generating the sludge in this way even if the printing plate is developed repeatedly by the developer consisting of the aq. silicate soln. of the high pH. The processing of the planographic printing plates of both negative and positive types by using one kind of the developer and one unit of automatic developing machine is, therefore, possible. |
