| 摘要 |
<p>A rotary printing press eg for multi-colour use omits the customary gearing for ensuring print registration between the plate cylinder (2) and the impression cylinder (1). Instead a microprocessor controlled control unit (20) for separate motors (9 and 6) driving the plate cylinder (2) and impression cylinder (1) maintains print registration during the operation of the press. This allows the plate cylinders to be rapidly brought onto impression because the control unit (20) will maintain registration despite separation of the plate cylinder (2) from the impression cylinder (1), and also allows each of the various plate cylinders (2) of a multi-colour press to be brought onto impression simultaneously when appropriate plate cylinder-moving means (14, 16) are provided. An optional facility provides for the printing plate to occupy only a portion of the cylindrical surface of the plate cylinder and for the angular velocity of the plate cylinder to be varied when there is no contact between the plate and copy medium at the printing nip (for the purpose of changing repeat length between successive print regions). <IMAGE></p> |
