| 摘要 |
PURPOSE:To always hold constant the speed at which sheets are fed regardless of changes in roller diameter by measuring the time required for each sheet to be fed by predetermined distance by a pair of control rollers, and controlling the speed at which the pair of control rollers feeds the sheets so that the time measured equals the time desired. CONSTITUTION:A pair of control rollers 8, which feeds sheets at variable speeds, is controlled by a sheet feed control means 10. The sheet feed control means 10 feeds the sheets by means of a pair of grip rollers 7 and supplies the sheets to an image forming portion 5 after forcing the ends of the sheets to abut to a pair of control rollers 3 to position the sheets. In this case, the time from the start of driving of the pair of control rollers 8 to detection of the ends of the sheets by a sheet sensor 9 is measured. The driving speed of a stepping motor for driving the pair of control rollers 8 is calculated according to the difference between the measured and desired times. A driving speed stored in a feed speed storage means 14 is renewed by the driving speed calculated. The speed at which the sheets are fed is therefore always held constant. |
