| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having a structure capable of minimizing image failure by performing loop control with high accuracy in multiple stages regardless of variation in the output of an optical sensor according to various sheets with different optimum amounts of the loop. <P>SOLUTION: In a laser beam printer, a loop detection device 92 comprises a detection lever 103 that comes in contact with a sheet conveyed on a sheet conveyance path to oscillate according to a loop of the sheet and a first optical sensor part 17 that outputs on/off signals partitioned into a plurality of partitions according to the oscillation position of the detection lever 103. In addition, the loop detection device 92 comprises a second optical sensor part 18 that detects the amount of light gradually changing according to the oscillation position of the detection lever 103. Then, the laser beam printer is so structured as to determine which partition an on/off value of the first optical sensor part 17 corresponds to, based on the amount of light detected by the second optical sensor part 18, to detect the loop amount of the sheet. <P>COPYRIGHT: (C)2012,JPO&INPIT |
