| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electrphotographic device capable of solving the problem of a focus divergence generated from an extremely shallow focus depth which is the defect of an optical system using a laser beam of the wavelength range of 380 to 500 nm. <P>SOLUTION: The electrophotographic device using a laser scanner whose light source is a semiconductor laser (Blue LD) beam of 380 to 500 nm and writing a latent image to a charged photoreceptor body is provided with the focus adjusting function of the laser scanner onto the photoreceptor body and the process of judging a focus matching degree by toner image information obtained by a development means. Also, patch-like dot or line images at the time of the DC components of a specified development bias are prepared, it is judged that the focus matching degree is highest when the difference of the reflection density becomes smallest in comparison with the reflection density measured when focus is matched, and focus adjustment is carried out. <P>COPYRIGHT: (C)2003,JPO |
