RECORDING PAPER CARRYING SPEED DETECTING METHOD, RECORDING PAPER CARRYING SPEED CONTROL METHOD AND IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To reduce the elongation of an image and to increase printing magnification accuracy without causing the increase in a cost due to the addition of a member such as a reflection plate, and without causing failures such as the deterioration of detection accuracy due to the deterioration of a member such as a TOP sensor. SOLUTION: A current (or voltage) applied on a transfer roller (transfer member) 8 is made differ in the sates between that before and after the recording paper P passes through and that it is passing. Then, the timing of this change is detected, and a time required to let the recording paper from the leading end to the trailing end through the transfer material is obtained based on the detected timing. The recording paper carrying speed is calculated based on the obtained time and the size of the recording paper. An alternation control is performed so that the calculated carrying speed may be equal to the target carrying speed. COPYRIGHT: (C)2007,JPO&INPIT