Abstract: A device for controlling the application of a bias for development in electrophotographic image forming equipment which forms a latent image on a photoconductive element and develops it by a magnetic brush formed by a dry two-component developer on a developing sleeve to which the bias is applied. A detector is located between the optics and the developing unit for detecting the passage of opposite ends of a charged area of the photoconductive element one by one. The bias is turned on and then turned off, each later than the detection of a particular edge of the charged area by a period of time in which the edge travels from a sensing position to a developing position. The bias applied to the developing sleeve is turned on at the time when the leading edge of the actually charged area of the photoconductive element arrives at the developing position, and it is turned off at the time when the trailing edge of such an area passes the developing position.

Abstract: A color electrophotographic copying process utilizing the Carlson process. A colored original to be copied is color-separated and read by a solid-state image pickup device. Color compensation or gradation compensation is carried out on the basis of the data read by the solid-state image pickup device. When the color compensation is effected, amounts of masking are determined on the basis of the data read by the solid-state image pickup device, and the color-separated latent images are partially erased in an area-modulating manner dependent on the determined amounts of masking with an eraser having a light-emitting dot array. When the gradation compensation is effected, the latent images are partially erased with the eraser in an area-modulating manner dependent on the determined amounts of masking, or an appropriate gradation reproduction curve is selected on the basis of the data read by the solid-state image pickup device.

Abstract: A method of and an apparatus for producing duplicates of a document in color wherein a plurality of photosensitive members in drum form are rotated in the same direction and exposed to respective color-separated optical images of the document through respective arrays of gradient-index rod lenses to form electrostatic latent images on the photosensitive members while the document is supported on a document support member and moved in the same direction as the rotation of the photosensitive drums. The electrostatic latent images on the photosensitive members are developed in different colors into visible images of different colors which are printed by transfer-printing on a sheet of support material on a transfer-printing belt moved in a direction opposite the direction of movement of the document support member for light exposure of the photosensitive members.

Abstract: Multicolored image forming apparatus wherein image processing is accomplished by exposing a photosensitive drum through an exposure optical device to the reflected light beam from the document illuminated with a lamp, reading the document image by an image sensor, energizing, by means of the processed signal of the output of the sensor, each LED in an eraser consisting of an LED array offset from the exposure slit center along the photosensitive drum in the width direction thereof, and erasing it.The light source simultaneously illuminates the document illumination position for slit exposure and a position offset from its center by a distance equal to the displacement between said erase position and the exposure position. The image sensor receives the light beam reflected from the document.

Abstract: A photoconductive sheet is wrappingly attached to an electrically conductive, grounded rotary drum so that part of the drum is covered by the sheet and another part of the drum is exposed. A magnetic brush developing member comprises a magnetic core and an electrically conductive sleeve surrounding the core. An electrically insulative layer is formed on the periphery of the sleeve. The core and/or sleeve are rotated to pick up toner particles which brushingly engage with the sheet to develop an electrostatic image formed thereon. A bias voltage is applied to the sleeve to prevent adherence of toner particles to white areas of the image. A regulator device maintains the bias voltage constant to prevent detrimental effects of charge buildup and dissipation across the electrically insulative layer on the sleeve of the magnetic brush.