| 摘要 |
PROBLEM TO BE SOLVED: To restrain generation of spoilage by a method wherein ink removing can be effected without any excess or shortage in respective printing units, in a case when the printing plates of respective printing units are exchanged all together. SOLUTION: Upon exchanging the printing plates of respective printing units all together, N1, N2, N3, N4 (N4>N3>N2>N1) are set for number of removing sheet in respective printing units as the values considering ink trapping (102). Ink removing is effected in respective printing units at the same time and when the printing number of sheets NA of a first color has arrived at the value N1, the impression throw-off of the first color is effected (105), and when the printing number of sheets NB of the second color has arrived at N2, the impression throw-off of the second color is effected (107), then, when the printing number of sheets NC of the third color has arrived at N3, the impression throw-off of the third color is effected (109) and when the printing number of sheets ND of the fourth color has arrived at N4, the impression throw-off of the fourth color is effected (111). |
