Abstract: An electrophotographic copying apparatus comprises a photosensitive member (4) exposed by light reflected from an original to form an image of the original thereon, mechanism (13) for developing the image on the photosensitive member with toner (9, 10, 11, 12) to produce a toner image corresponding the image mechanism (24) for transferring the toner image onto a transfer material, mechanism (26) for fixing the toner image transferred on the transfer material, mechanism (27) for producing a signal which represents that high surface glossiness of the image copy is required, and mechanism (31, 32) for feeding the transfer material in a first path when the signal is produced, the transfer material being fixed fully, and for feeding the transfer material in a second path shorter than the first path when the signal is not produced.

Abstract: A method of cleaning a photosensitive member in an electrophotographic apparatus in which an electrophotographic operation is performed by charging the photosensitive member with a predetermined voltage, exposing the charged photosensitive member so as to form a latent image thereon and developing the latent image by use of toner, includes the steps of charging the photosensitive member with a half tone level voltage which is smaller than the predetermined voltage, and developing the charged photosensitive member by use of toner without exposing the charged photosensitive member, so as to form a uniform half tone toner image thereon. The cleaning method also includes the step of scraping off the toner of the uniform half tone toner image from the photosensitive member by a blade abutting thereto.

Abstract: A transfer roller device for transferring onto a copy paper sheet a full color toner image formed on an intermediate transfer belt. A rear-surface electrode roller disposed at the opposite side to a transfer roller with the intermediate transfer belt positioned in between, is divided into a plurality of cylinder members, and at least one of the cylinder members corresponding to the size of a copy paper sheet is separately connected to ground. With the arrangement, occurrence of an excess current through a portion of the intermediate transfer belt carrying no copy paper sheet thereon is eliminated, thereby preventing a filming phenomenon. In another arrangement, a plurality of rear-surface electrode rollers are disposed at respective positions associated with a plurality of respective copying speeds which are set according to copy paper sheets. Thus, a voltage to be applied between the transfer roller and the rear-surface electrode roller is maintained constant regardless of different copying speeds.

Abstract: A copying apparatus in which a screen for improving gradation characteristics of a copied image can be retractably projected into an optical path, including a device for setting, when the screen is placed in the optical path and retracted from the optical path, a developing voltage to a first value and a second value, respectively such that the first value is lower than the second value.

Abstract: An electrophotographic apparatus having: a developer unit that has a magnetic developing roller for applying toner to electrostatic latent image areas formed on the surface of a photoconductor and that has a shutter which is closed to regulate the distribution of the toner to the photoconductor, a developing bias voltage for controlling adherence of the toner to the photoconductor being applied to said developer unit; and a bias voltage source for applying, when the shutter of the developer unit is closed, a developing bias voltage of the level between 0V and the developing bias voltage applied when the shutter is opened, thereby preventing blank spots from appearing in transferred images without increasing image-overtoning and also preventing damages from being caused to the surface of the fuser rollers of a fuser unit.

Abstract: A copying apparatus having a prescanning function for obtaining density data to adjust copy parameters includes a correction function which eliminates the data obtained from a portion of a predetermined color, from the density data detected on a prescanning process. The density data can be restricted within a predetermined range. The predetermined range can be easily set by the user.

Abstract: A color copier includes an optical sensor unit and analyzes colors of reflected light from an original to be copied by detecting spectroscopic color data of the reflected light. Amounts of toner of different colors for forming a color image are determined according to such detected spectroscopic color data.

Abstract: A light source device for use in a color copying machine comprises a plurality of light source lamps having different efficiencies respectively and means for lighting any number of light source lamp or lamps among said plural light source lamps depending on the luminous energy of the respective blue, green and red spectrums and/or the spectral sensitivity of the photosensitive member for said respective spectrums.

Abstract: A color copier operable both in monochromatic and full-color copying modes is controlled by a central processing unit programmed to exercise a real-time control of operation by detecting image characteristics of an original to be copied if a monochromatic copying mode is selected. If a full-color copying mode is selected, the image characteristics are preliminarily detected by scanning before a copying operation is started.