| 摘要 |
PURPOSE:To prevent the degradation in the developability of a negative type photosensitive planographic printing plate which arises at the time of commonly processing the negative type and positive type photosensitive planographic printing plates by incorporating sulfite into a replenishing liquid. CONSTITUTION:The sulfite is incorporated into the replenishing liquid at the time of executing a development processing by using an automatic developing machine and compensating the decrease in the development activity by the replenishing liquid. Alkaline metal salts, such as sodium, potassium and lithium, alkaline earth metal salts, such as magnesium, and ammonium salt, etc., are useful as the sulfite. The concn. of the sulfite is confined in a 0.1 to 10wt.% range in the developing soln. to be repetitively used. The degradation in the developability of the negative type photosensitive planographic printing plate which arises at the time of subjecting the negative type photosensitive planographic printing plates and the positive type photosensitive planographic printing plates commonly with the same developing soln. is prevented over a long period of time. |
