Patent ID: 7552995
Filing Date: 2009-06-30
Classification: B41J

Abstract:
1. A duplex printing system, comprising: a first printer for forming an image on a first side of a web without a feed hole; a second printer which is provided in a backward stage of the first printer and forms an image on a second side of the web; a control device for transporting print data and a web transport signal indicating instruction of printing to the first printer and the second printer; a setting portion to assign a setting value indicating a position of an alignment mark on the web; mark detection means for detecting the alignment mark formed on the web; and image alignment control means for matching a position of the image formed on the second side with a position of the image formed on the first side of the web by controlling a transport speed of the web so as to match a phase of the web transport signal with a phase of a mark detection signal from the mark detection means, wherein the image alignment control means has position information indicating a position in which the alignment mark is formed and calculation means for calculating timing at which the alignment mark is to be detected by the position information, wherein the image alignment control means aligns the images based on the alignment mark detection timing calculated by the calculation means, and wherein when a previously applied mark comprising a mark, other than the alignment mark, is formed on the web, the setting value is set to indicate a position in which the previously applied mark is not formed.