| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus such as a color laser beam printer, the apparatus being designed so as to solve the problem in which dust and toner fall on the beam emitting aperture of an optical scanning device and adhere to the surface of a sealing glass and so as to reduce the size and cost of the main body of the apparatus. <P>SOLUTION: A shutter member 60 is disposed on the outside of a developing unit 13, and is rotated between an optical path blocking position F and an optical path unblocking position E. In synchronization with an image forming operation, specifically the operation of the developing unit 13, the shutter member 60 moves from the optical path blocking position F to the optical path unblocking position E, thereby retracting. When image formation is not carried out, the shutter member 60 moves from the optical path unblocking position E to the optical path blocking position F, thereby blocking the optical path of a laser beam A. That is, in carrying out cartridge replacement or maintenance when image formation is not carried out such as a period of time that the operation of a printer is stopped, the shutter member 60 receives and blocks powder such as dust and toner falling due to vibration or impact applied on account of the replacement or maintenance. This prevents falling powder from adhering to the surface of the sealing glass 44 closing the beam emitting aperture of the optical scanning device 40, resulting in a decrease in beam transmission performance and hence degradation in image quality. <P>COPYRIGHT: (C)2008,JPO&INPIT |
