| 摘要 |
PURPOSE:To attain image recording with high resolution by uniforming the diameters of respective picture elements to be recorded by specifying an optical beam condition and an optical beam scanning condition in the main and sub-scanning directions. 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 in 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. When it is defined that the ratio of a beam diameter in the main scanning direction to a picture element pitch in the main scanning direction is rhoy, the ratio of a beam diameter in the sub-scanning direction to a picture element pitch in the sub-scanning direction is rhox and the ratio of an optical beam exposing time to a one-picture element scanning time at the border between an image part and a non-image part is Td, 1.0<=rhox/rhoy<=1.5 and 0.5<=rhoy.Td<=1.5 are satisfied. An electrostatic latent image formed by said exposure is developed by a developing device 5 and transferred to recording paper 6. Consequently, an image having the same diameter of the picture elements in the main and sub-scanning directions and high resolution can be recorded. |
