| 摘要 |
PROBLEM TO BE SOLVED: To stably produce a plate with low tackiness by exchanging the water used in a post-exposure process for every two or less plates. SOLUTION: By the study of insufficient post-exposure due to contamination of a post-exposure water, it is found that after three plates are treated, the water has 70% transmittance for UV rays of >=300nm wavelengths, 5% transmittance for UV rays of <=300nm wavelengths, and especially, the most of sterilizing rays can not reach to the plate surface after three plates are treated. This is because a material depositing on the plate surface pollutes the post-exposure water, and as a result, transmittance for UV rays and sterilizing rays in the water is decreased. To prevent the decrease in the transmittance, the post- exposure water is exchanged for every two or less plates, or water is always supplied and discharged. Thus, contamination in the post-exposure water can be suppressed to the min. By this method, the decrease in the transmittance for UV rays of >300nm wavelengths and sterilizing rays can be prevented and the tackiness of the surface of a printing plate can be decreased. |
