PRESS
Diagnosing differences in registration

April 2007

multipage

Differences in registration after perfecting can have multiple causes and cures. When second-side misregistration occurs, look into the following:

* The rotary movement of the suckers at the rear edge of the sheet may be switched off. Switch on the rotary movement of the suckers.

* If there are cutting variations in the paper pile, recut paper to restore consistency.

* Thin paper may collapse at the front lays. To prevent this, engage all front lays.

* The problem may be a different gripper bite on the drive side and the operator side. Set a parallel gripper bite on the drive side and the operator side in the control console.

* When it pulls off the blanket, the sheet may be stretched by excessive adhesion to the blanket surface. Address this by reducing the printing pressure (contact pressure) between blanket cylinder and impression cylinder. Another corrective is to use a blanket with quick-release properties.