| 摘要 |
PURPOSE:To obtain a sharp copied image by subjecting a photoconductive toner to frictional electrostatic charging prior to the formation of a toner layer then to main electrostatic charging to the polarity opposite from the polarity of the frictional electrostatic charge. CONSTITUTION:The frictional electrostatic charge is preliminarily applied to the photoconductive toner to the specified polarity and thereafter the toner layer is formed on a substrate by using such toner. The image is exposed by subjecting the toner layer to the main electrostatic charge of the polarity reverse from the polarity of the frictional charge. The photosensitivity of the toner is improved by the combination of the frictional electrostatic charge and the main electrostatic charge in the above-mentioned manner. The electrostatic latent images formed in the exposed part and non-exposed part have the charges of the polarities reverse from each other and can be electrically and thoroughly discriminated. As a result, the sharp image having excellent contrast is obtd. The negative or positive image is easily obtd. by changing the electric polarities in the stage of transfer. |
