Patent ID: 7188564

Claim:
A duplex printer capable of switching between a simplex print mode and a duplex print mode, comprising: a printing section including a print drum and a press roller, the press roller being provided so as be movable into or out of contact with the print drum; a sheet feeding section for feeding a sheet toward the printing section; a sheet discharging section for discharging to an outside of the printer a printed sheet on which printing has been performed in the printing section; an auxiliary tray for temporarily retaining thereon a front-side-printed sheet having a print image formed on its front side in the printing section; refeeding means for refeeding the front-side- printed sheet retained on the auxiliary tray toward the printing section; and a path selector for steering the sheet coming out of the printing section to either the auxiliary tray or the sheet discharging section, wherein, in the duplex print mode, a master having a first perforated image and a second perforated image formed thereon side by side, is wound around the print drum, and a first sheet is fed to the printing section from the sheet feeding section to print a first print image corresponding to the first perforated image on a front side of the first sheet, and after the first sheet having the first print image printed thereon is steered toward the auxiliary tray by the path selector, a second sheet is fed to the printing section from the sheet feeding section to print a first print image corresponding to the first perforated image on a front side of the second sheet while the refeeding means feeds the first sheet to the printing section again to thereby print a second print image corresponding to the second perforated image on a reverse side of the first sheet, and the first sheet and the second sheet are steered by the path selector toward the sheet discharging section and the auxiliary tray, respectively, and means for effecting position adjustment on each of the first and second print images with respect to each of the first and the second sheets in a sheet conveyance direction, with position adjustment on the first print image being effected by changing a sheet feeding timing of the sheet feeding section and position adjustment on the second print image being effected by changing a refeeding timing of the refeeding means.