| 摘要 |
PURPOSE: To provide a high quality two-color printer which is stabilized with time by controlling the grid voltage of a first electrostatically charging member so as to stepwise change in accordance with the rotation time of a photoreceptor. CONSTITUTION: At the first rotation of the photoreceptor 1 of a two-color electrophotographic system printer performing two-color printing by rotating the photo-receptor 1 twice; after the photoreceptor 1 is electrostatically charged by the electrostatic charging member 2 with a grid of a scorotron system for performing first electrostatic charging and the electric latent image of a first color is formed on the photoreceptor 1 by a first exposing member 3 using laser, development with the toner of the first color on the photoreceptor 1 is performed by a first developing member 4 using two-component developer and brought close to the photoreceptor 1 by a retract mechanism. Then, electrostatic charging is performed again as second electrostatic charging using the electrostatically charging member 2 used for the first electrostatic charging at the second rotation. Then, grid voltage at the time of the first electrostatic charging is stepwise controlled in accordance with the value of a counter 10 counting the rotation time of the photoreceptor 1, so that the potential of the photoreceptor 1 after the first electrostatic charging is in a target range against the electrostatic charging deterioration with the lapse of time of the photoreceptor 1. |
