PRINTER, PRINTING METHOD, AND PLATE TREATING DEVICE

摘要

Provided is a printer comprising at least two printing units having rotatable printing drums, on which printing plates having image areas for transferring printing images to sheets of printing paper are circumferentially wound, and juxtaposed in a mode to print the printing paper sheets sequentially, a reversing device arranged between the two printing units for receiving the printing paper sheets from the printing unit on the upstream side and for transferring the printing paper sheets, while reversing the surfaces and backs and the tops and bottoms of the printing paper sheets, to the printing unit on the downstream side, and a phase adjusting device for changing the phase of the printing drum of at least one printing unit. On the basis of the top and bottom sizes of the printing paper sheets, a rotation angle for changing the phase of the printing drum in at least one printing unit is obtained in a mode for displacing the relative position of each printing image to be printed on the surface and back of the printing paper sheet by the two printing units is acquired, so that the printing drums are rotated at the rotation angle by the phase adjusting device. As a result, it is possible to adjust the positions of the printing image to be printed on the surface of the printing paper sheet and the printing image to be printed on the back, in the top and bottom directions.