| 摘要 |
PROBLEM TO BE SOLVED: To achieve both the prevention of a defect in image quality such as a white stripe or a black stripe caused by the soiling of an electrifying roll and the prevention of a defect in image quality such as a void caused by a discharge product. SOLUTION: By applying voltage including peak-to-peak voltage lower than voltage twice as high as discharge start voltage to the electrifying roll, negative discharge is intermittently generated and the surface potential of a photoreceptor becomes constant soon. The total amount of discharge is comparatively small because positive discharge is not generated, thereby hardly causing the void in high-temperature and high-humidity environment. Since the direction of electric field between the electrifying roll and the surface of the photoreceptor is repeatedly oscillated, the toner having a positive polarity repeatedly adheres to and separates from the electrifying roll even when the toner having the positive polarity somewhat exists in the toner. Therefore, a situation that the toner adheres to the electrifying roll and soils it is prevented. COPYRIGHT: (C)2006,JPO&NCIPI
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