Abstract: A method of removing electrostatic charge for erasing an electrostatic latent image from an electrophotographic photosensitive device having a conductive layer overlain by a photoconductive layer which in turn is overlain by a transparent insulating layer. The method comprises a first step of uniformly charging the photosensitive device by a D.C. charger while subjecting the photosensitive device to an exposure over the whole area thereof; a second step of effecting a charging for adjustment of potential level so as to adjust the potential of the photosensitive device from the level obtained as a result of the charging in the first step to the aimed level; and a third step of exposing the whole area of the photosensitive device. With this method, it is possible to remove electrostatic charge almost perfectly to eliminate undersirable shift of the potential of the photosensitive device after the erasion.

Abstract: An electrophotographic process and apparatus for performing the process which employs an electrophotographic photosensitive member of a basic construction in which a photoconductive layer and a transparent insulator layer are sequentially laminated on the surface of a conductive supporter. The process comprises a first step of providing a primary charge uniformly from the surface side of the transparent insulator layer, a second step of performing a secondary corona charging during an imagewise exposure by applying a square wave voltage whose voltage-time integration value of a polarity reverse to the primary charge is larger than that of the same polarity thereas and a third step of forming an electrostatic latent image on the surface of the transparent insulator layer by applying a uniform exposure.

Abstract: A developing apparatus for an electrophotographic copying machine includes a developer carrier disposed in opposing relationship with a member on which an electrostatic latent image is formed. A vibrator comprising a single sheet piezoelectric element which is adapted to undergo vibrational oscillation in the direction of its thickness or a plurality of such elements bonded together is closely engaged with the developer carrier to cause the developer to fly toward the latent image carrying member.

Abstract: In an electrophotographic photosensitive device including a conductive layer, a selenium based photoconductive layer and a transparent insulating layer which are sequentially laminated, the conductive layer is formed by an aluminum substrate conductive layer, a zinc conductive layer (or a zinc conductive layer and a copper conductive layer), and a nickel conductive layer which are sequentially laminated to each other. As a result of this structure, the charge injection characteristic during the primary charging step is improved, and the charge injection preventing characteristic during the simultaneous secondary charging and image exposure steps is sufficiently maintained. The conductive layers contact each other intimately. The electrophotographic photosensitive device exhibits a high humidity durability and a long life and can obtain high electrostatic contrast.

Abstract: In an electrophotographic photosensitive device including a conductive layer, a selenium based photoconductive layer and a transparent insulating layer which are sequentially laminated, the conductive layer is formed of an aluminum substrate conductive layer, a zinc conductive layer a copper conductive layer, and silver conductive layer which are sequentially laminated to each other. As a result of this structure, the charge injection characteristic of the photosensitive device during primary charging is improved, and the charge injection preventing characteristic during the simultaneous secondary charging and image exposure steps is sufficiently maintained. The conductive layers contact each other intimately. The electrophotographic photosensitive device is highly humidity durable and exhibits a long life and can obtain high electrostatic contrast.

Abstract: An electrophotographic process employs an electrophotographic photosensitive member of a basic construction in which a photoconductive layer and a transparent insulator layer are sequentially laminated on the surface of a conductive supporter. The process in one preferred embodiment comprises a first step of providing a primary charge uniformly from the surface side of the transparent insulator layer, a second step of performing a secondary corona charging during an imagewise exposure by applying an a.c. voltage in which the firing angle of a negative half wave is controlled in phase to be within a phase angle corresponding to a lower voltage than the firing angle so that the positive discharge period may be longer than the negative one during one period, and a third step of forming an electrostatic latent image on the transparent insulator layer by applying a uniform exposure.

Abstract: A photosensitive member for electrophotography basically comprises a conductive support, on the surface of which a photoconductive layer and a transparent insulating layer are sequentially laminated. The photosensitive member is adapted to be used in a process for forming an electrostatic latent image including sequential steps of a primary corona charging concurrent with imagewise exposure, a secondary corona charging and a flush irradiation. The surface of the conductive support is treated to a mirror finish, based on experimental finding that the contrast voltage of the latent image depends on the degree of surface roughness of the support.