Single and perfecting press - has asymmetric working cycle compensating for change from single to perfecting mode

摘要

To compensate for the change in relative timing of two sequential printing units when changing from the single to the perfecting mode, the engagement of the two printing cylinders is controlled by a shift register timed to produce an asymmetrical working cycle whereby the engagement of the second cylinder is delayed to allow for perfecting the largest intended sheet. Mechanically, the second cylinder (12) is engaged by a cam (16) whose follower is made operative by an output of the register during the idle part (a) of the cam contour, which part is long enough to allow the follower to be made operative during single or perfecting work.