| 摘要 |
PROBLEM TO BE SOLVED: To maintain the entire job at a normal image magnification even when a sheet of paper changes due to a tray change when the job is carried out.SOLUTION: When a tray is changed with a transfer roller kept firmly pressed (during consecutive operation) after the passage of a fourth sheet of paper, a control section calculates average speed V4 of a transfer section drive motor during the passage of a first sheet of paper (a fifth sheet of paper in series) after the tray is changed, and restores the calculated average speed V4 in a storage section as a reference value. When a sixth sheet is passed, the control section calculates average speed V5 of the transfer section drive motor during the passage of the sixth sheet of paper. The control section then calculates a difference X3 between a measured value of the average speed V5 and a reference value for the fifth sheet of paper stored in the storage section. The control section provides the difference X3 as feedback for a torque command value for a seventh sheet of paper, which is the successive sheet of paper. Accordingly, since the speed decreased as a result of being affected by a thick sheet of paper can be used as reference speed, an image after the tray is changed can be maintained at a normal magnification. |
