| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of reducing consumption power without deteriorating image quality. <P>SOLUTION: An optical scanner comprises four light sources, a polygon scanner comprising a polygon mirror for deflecting a luminous flux from each light source and a motor mechanism for rotatingly driving the polygon mirror, four scanning optical systems for individually condensing the luminous flux deflected by the polygon mirror on the surface of four photoreceptor drums, four optical detection sensors (2111a to 2111d) provided corresponding to the four photoreceptor drums, a scanning control device 3022 and the like. And, the scanning control device monitors the reduction in reflectivity of the deflective reflection face of the polygon mirror based on the output signal of each optical detection sensor, and if the level of any output signal is smaller than the level threshold value, the scanning control device performs the reflectance recovery process by rotating the polygon mirror at a rotation rate higher than that during formation of an image. <P>COPYRIGHT: (C)2012,JPO&INPIT |
