Patent ID: 8351829
Filing Date: 2013-01-08
Classification: G03G,H04N

Abstract:
1. Method of preventing a registration error while printing at least one printing image, wherein, in order to control or adjust the correct length of the printing image, the start and/or the distance of the printing image lines of the printing image are controlled by determining the ratio of the number of rotary encoder signals of a transport web counted during a specific time interval, said transport web transporting the printing sheets, to the number of rotary encoder signals of a cylinder of a printing unit detected during the same time interval, said cylinder participating in the printing operation and moving directly or indirectly with the transport web, and by taking into account a change of this ratio as a correction, said ratio being a function of a printing sheet located in a printing nip between the transport web and the printing unit, and whereby, in order to achieve the desired registration accuracy, a certain mean value of time is determined by way of determining said ratio, wherein a changed printing material situation occurring in said printing nip between the transport web and the printing unit is used to achieve registration accuracy by immediately taking into consideration a correction value that takes into account the changed printing material situation, wherein, during the current control step, a control device that is being used is re-initialized with the appropriately stated correction value for control of the registration accuracy of the currently to be printed sheet, said sheet being subject to the mentioned change of the printing material situation, and that, as a result of this, transient phases otherwise caused by a delayed response of the control device are prevented, and wherein a printing material gap existing between two successive sheets is masked relative to the control device or in the control device.