| 摘要 |
PROBLEM TO BE SOLVED: To clean off contaminants adhering to the surface of a sheet carrying roll following up a sheet even when the sheet is not carried in high speed simultaneous perfecting process by switching the driving system of the sheet carrying roll between follow-up driving and independent driving at the time of printing and stopping print. SOLUTION: A motor 19 for driving a sheet feed roll 11 independently and a follow-up/independent driving switch 20 are coupled with the sheet feed roll 11. Follow-up system is employed at the time of printing in order to prevent an image from being disturbed at a part touching a sheet 10 and independent driving system is employed at the time of nonprinting. A sheet touching/ separating unit 21, the motor 19 and the switch 20 switch the driving system of the sheet feed roll 11 from follow-up system to independent driving system at the time of stopping print, e.g. jamming of sheet, and the sheet feed roll 11 is turned while separating the sheet 10 therefrom thus cleaning the sheet 10 by means of a cleaning brush 15. According to the arrangement, an image of good quality can be obtained constantly. |
