| 摘要 |
PURPOSE:To prevent a sheet from being jammed and damaged by providing a sheet thickness detector for detecting the thickness of a sheet on entry side of a positioning belt, and increasing and decreasing the contact pressure of a slip roll according to a signal of detected thickness of reliably bring a sheet into contact with a gate regardless of thickness. CONSTITUTION:When a sheet is transported between a driving roll 18 and a pinch roll 16 of a sheet thickness detecting mechanism 12 disposed on entry side, the thickness of a sheet is detected from surface pressure of the pinch roll 16, which varies with the thickness of a sheet by a sheet thickness detector 19, and an operation signal is sent to driving means 11 through a control unit 20, so that a slip roll 7 fixed to an arm 10 is lowered to increase the nipping force between the slip roll 7 and the positioning belt 6. Thus, a thick sheet can be reliably fed until the leading end thereof is brought into contact with a gate. On the contrary, in case of a thin sheet, the nipping force is decreased, so that the thin sheet is kept from buckling when the leading end of the sheet is brought into contact with the gate to reliably prevent jamming of the sheet and damage of the leading end of the sheet. |
