| 摘要 |
PURPOSE:To provide a rotary printing press capable of continuously printing without replacing a form cylinder even when printing pitch is changed, wherein the velocity of a paper is controlled to be different from the circumferential velocity of the form cylinder when a printing plate is not making contact with the paper. CONSTITUTION:The gear ratios of a gear train of a planetray gearing extended from a gear 25 of the form cylinder 4 to an impression cylinder 15 are so set that the circumferential velocity of the cylinder 4 and that of the cylinder 15 are equal to each other when a constant-speed motor 26 is rotated while a variable- speed motor 21 is stopped. The motor 21 is stopped when the printing plate 5 for the first color comes to a printing position (a) for the first color, from which moment on the velocity of the paper is synchronized with the circumferential velocity of the cylinder 4, and printing is conducted by the cylinder 4. When the rear end of the printing plate 5 for the third color comes to a printing position (c) for the thrid color, the motor 21 is started to rotate. The circumferential length l of the impression cylinder 15 from the position (a) to the position (c) is set to be not larger than the difference between the circumference Ls of the cylinder 4 and the length Lp in which printing in three colors can be conducted. |
