| 摘要 |
PROBLEM TO BE SOLVED: To provide a density detection sensor unit stably detecting a toner image carried on a photoreceptor drum 1 over a long term with high performance by decreasing forming speed of frictional flaw on a transparent window 11a and melting speed of toner. SOLUTION: One shutter opening state stopping position and two shutter closing state stopping positions are set in a moving path along a shutter cover 16 of a shutter 17. In a stage in which the shutter 17 is moved to reciprocate from a home position (c) that is the ordinary shutter closing state stopping position to the shutter opening state stopping position (b), a cleaning member 25 does not rub the transparent window 11a. Every time ordinary reciprocation is performed by a thousand times, the shutter 17 is moved to reciprocate to a cleaning stopping position (a). At such a time, the cleaning member 25 scrapes adhering toner by rubbing the transparent window 11a to reciprocate twice. COPYRIGHT: (C)2009,JPO&INPIT |
