| 摘要 |
PROBLEM TO BE SOLVED: To prevent release and deposition of preprinting ink by providing a plate surface dry preventing means for preventing drying of a plate cylinder surface after ink is scraped by a doctor, thereby suppressing an increase of adhesive force of postprinting ink. SOLUTION: A printing unit 3 has a cover 13 fixed to a doctor unit 11. This cover 13 is extended to a position having no difficult of conveying a printing sheet 6 wound on an impression cylinder 12 toward the cylinder 12, and a substantially sealed space is formed by the cover 13, doctor unit 11, plate cylinder 10 and cylinder 12 wound with the sheet 6. With this constitution, evaporation of solvent contained in an ink film scraped down by the unit 11 can be suppressed by the cover 13. Thus, the ink film of the non-printing element in which the evaporation of the solvent is suppressed is not increased in its adhesive force, and hence preprinted ink of the sheet 6 is not released. And, it is not transferred as dirt to the sheet 6 by pressing force of the cylinder 12. |
