| 摘要 |
PURPOSE:To record an image with high resolution by scanning optical beams so that the ratio of optical beam exposing time to one picture element scanning time satisfies a specific condition at a border between a picture part and a non- picture part. CONSTITUTION:A light source 1 consisting of a laser diode is turned on and off in accordance with binary picture information BS, a directly modulated laser beam is sent is a sub-scanning direction through an optical scanning system and a correcting optical system 2 and the surface of a drum-like photosensitive body 4 which is uniformly charged electrostatically by a charger 3 is exposed by irradiating said laser beam successively in the main scanning direction. In this case, the laser beam is scanned at the border between the image part and the non-image part so that the ratio Td of the laser beam exposing time to the one picture element scanning time satisfies a fixed condition corresponding to the formula I . An electrostatic latent image formed by the exposure is developed by a developing device 5 and transferred to recording paper 6. |
