PURPOSE: To correct the positional slippage of a pattern from a printed pattern and to facilitate the manufacture of a plate cylinder by a constitution wherein a mechanism fo detecting a phase difference between the pattern of an endless- belt-shaped plate cylinder of a rotary printer printing discontinuos patterns and a printed pattern on paper is linked to a mechanism for controlling the speed of rotation of the plate cylinder or a positioning mechanism therefor.

CONSTITUTION: A mark P is attached to an appropriate place in a blank part (b) located in front of a pattern 3' of a plate cylinder 1, while a mark Q is attached in a blank part (a) located in front of a position on printing paper 6 whereat a printed pattern is formed, and the time points of passage of the two marks P and Q are detected by photoelectric detecting devices 8 and 9. When the feeding speed of the plate cylinder 1 is controlled, the speed of rotation of a rotating cylinder is adjusted by counting a timing whereat the blank parts (a) and (b) reach the position of transfer printing. When the position of the pattern of the plate cylinder 1 is corrected, a guide cylinder 5 is made separable from the rotating cylinder 4, while only the blank part (b) of the plate cylinder 1 is made flexible so as to be matched with the blank part (a) of the paper 6.