| 摘要 |
PURPOSE:To facilitate setting of formation of a positive image similar to an original or a negative image, by forming a static latent image consisting of positive and negative surface voltages and by applying positive or negative corona discharges for modulation to this image. CONSTITUTION:Photosensitive screen 4 having photoconductive layer 2 and insulating layer 3 on conductive screen 1 is charged uniformly and negatively on layer 3 by pre-charging. Subsequent exposure to light 12 from original 11 and AC corona discharge render positive the surface voltage of light area L of layer 3. Following uniform whole surface exposure forms a static latent image with changed voltage on dark area D of layer 3. Succeeding application of modulation corona discharge across corona wire 8 and conductive substrate 5 of recording material 7 through voltage sources 9 and 10 connected to screen 1 hinders passing of positive corona ions in virtue of an electric field shown by full lines alpha on light area L. On the other hand, on dark area D, the electric field shown by full lines beta permits the corona ions to effectively arrive at insulating layer 6 of material 7 in a state of the latent image slightly erased. |
