Abstract: A color image forming apparatus for forming a toner image on a transparent member used in combination with overhead projectors including a speed switch for switching the process speed while an image carrier is rotating, after toner images of a number of colors are formed on the image carrier; a process control for controlling the transfer conditions under which the toner images are transferred onto the recording medium, in response to switching of the process speed; and a selector for selecting an overhead projection mode including a voltage switch for reducing voltage applied to the transfer device after a predetermined time has elapsed. Preferably, the process control includes a fixing temperature control for controlling the fixing temperature of the recording medium having the toner images transferred thereon.

Abstract: A color image forming method and apparatus for sequentially forming toner images of a plurality of colors on a photosensitive body so as to form a color toner image. The method and apparatus maintain a substantially constant developing bias so that a first exposure potential of a photosensitive surface and a second exposure potential of the photosensitive surface are substantially equal to one another.

Abstract: A method of cleaning an image retainer by removing remaining toner particles from the retainer after transferring a multi-color toner image which is obtained by a multi-color toner image forming process wherein charging, image writing-in, and developing steps are repeated at least twice, abutting a cleaning member against the retainer after a final image writing-in step of the image forming process has been completed, and releasing the cleaning member from abutment after the cleaning has been completed but not during the image writing-in step for forming a next multi-color toner image.

Abstract: A color image forming apparatus wherein a color image is formed by rotating plural times an image retainer and repeating a latent image formation and a development. The start timing of an image forming cycle is controlled by using one of reference signals corresponding to one of a plurality of predetermined positions on the image retainer and the start timing of another image forming cycle is controlled by using another of the reference signal.

Abstract: An apparatus for developing a latent image formed on a photoreceptor constituted a container for storing developer, a toner feeder for replenishing toner, a sensor for measuring the toner concentration in the developer, a memory for storing a reference measurement lying only with a certain range and which is obtained by measuring a reference developer having a reference toner concentration by the sensor, and a controller for controlling a toner concentration of the current developer by operating the toner feeder so that a current measurement obtained by the sensor becomes equal to the reference measurement.

Abstract: In a color image processing apparatus according to the invention, a color image signal being photoelectrically obtained by a image reader is separated into red, blue and black color component signals. A laser scanner writes respective latent images corresponding to the color component signals on a cylindrical photoreceptor. Each of the respective latent images are written during one rotation of the photoreceptor. The initial writing positions of the respective latent images are registered by using a drum index signal generated in synchronization with the rotation of the photoreceptor. An optical output starts outputting an optical signal in response to the index signal or an encoder signal selected according to the copy mode.

Abstract: An image recording apparatus wherein image information is developed by converting the image information into an optical signal and by writing the image information on a drum-shaped image retainer with the converted optical signal to provide latent images and by developing the latent images, which are then recorded. A first writing timing is set in a first writing direction with respect to the image retainer and a second writing timing is set in a second writing direction with respect to the image retainer and the number of rotations with respect to the image retainer is calculated in accordance with the settings of the writing timings. The image information is overwritten by a number of times corresponding to the number of rotations to provide a plurality of images which may be entirely or partially or not superposed on one another.

Abstract: An image reading apparatus for reading an image by using a plurality of image pickup elements, wherein the relative deviation of reading positions between the image pickup elements is detected from read outputs of the image pickup elements and the read outputs are corrected in response to the relative deviation. The image reading apparatus has a memory device for memorizing reading signals of the image pickup elements and a correcting device for controlling application of the reading signals to the memory device and an output of the memory device by the relative deviation.

Abstract: An image forming apparatus for conducting writing and developing operations several times on an image retainer and transferring the developed images to a transfer material. An output of a developing bias power source is sequentially distributed to a plurality of developing devices in the order in which the image retainer moves from an image signal writing device and the beginning of the abutment of a cleaning member against the image retainer and the beginning of the release from the abutment fall at timing other than at least the image writing timing.