| 摘要 |
PURPOSE:To make printing plates in quantities stably for a long period, and to reduce waste washing liquid and reduce the cost by using water having a specific hardness or below as washing water used repeatedly after a photosensitive lithographic plate is developed. CONSTITUTION:The lithographic plate 23 which contains an o-naphthoquinone diazide compound, etc., as a photosensitive component is developed by sending the processing liquid in a development processing tank 1 to spray pipes 10A, 10B, and 10C from a liquid feed pipe 4 by using a pump 7, and the plate is conveyed to right by using a roll 13 and conveyor rolls 14 and 15 to squeeze the developer by a squeeze roll through a brush roll 18. Then, the washing water prepared by incorporating acetic acid phosphoric acid, or their water soluble alkali metallic salts in washing water whose hardness is held below 100 by an ion exchange treatment, etc., is sent from a circulating washing tank 2 to a spray pipe 11 through a pipe 5 by a pump 8 and used repeatedly for washing, and then the water is sent to a treating tank 3 for desensitizing to fat. Thus, the washing water whose hardness is reduced is used, so this is used repeatedly for several months without flocculation to obtain printing plates stably, thereby reducing the amount of waste washing water to be treated greatly. |
