| 摘要 |
PURPOSE:To form an image which has no edge effect and the superior reproducibility of half-tones by carrying out the preliminary electrostatic charging of a photosensitive body and pre-exposure using a dot screen simultaneously or in specific order, and then performing primary charging and image exposure. CONSTITUTION:A photosensitive layer 2 is charged by a charger 3 through constant-polarity corona discharging in a preliminary charging process I . The light from a light source 12 is projected on the layer 2 as dots from a slit 14 through the dot screens 15 in a pre-exposure process II. The layer 2 after the preliminarily charging and dot pre-exposure is discharged by a charger 6 and the primary charging of the layer 2 is performed in a primary charging process III. The surface potential remains at an exposed part, corresponds to an exposed part, and disappears at a completely exposed part and potentials are left at an intermediate and a low exposed part respectively in an image exposing process IV. The layer 2 is developed with toner by a developing mechanism 8. In this case, individual electrostatic images with a constant potential level have a top- bottom potential gradient at any part of the image and toner sticks on any part of the image uniformly. |
