Abstract: The cleaning method for use in an electrophotographic copying apparatus of the type removing toner images remaining on the surface of a photoconductor by a cleaning blade which includes the steps of bringing the cleaning blade into pressure contact with the photoconductor at least prior to the movement of the photoconductor, and moving the cleaning blade away from the surface of the photoconductor after the movement of the photoconductor is stopped with completion of copying process.

Abstract: A plurality of copying machines (12), (13), (14) are connected to a computer (39). Each copying machine (12), (13), (14) comprises sensor means (16), (17), (18), (19), (21), (22), (23), (24) for sensing various operating parameters thereof such as a total number of copies produced, machine malfunctions, amounts of remaining copy sheets and toner, etc. These parameters are all transmitted to the computer (39) which processes and prints them out. In response to a copying machine malfunction the computer (39) feeds back to the malfunctioning copying machine instructions for correction. The instructions are displayed at the copying machine. The computer (39) further computes the degree of degeneration of the photoconductive element of each copying machine (12), (13), (14) and controls the imaging exposure intensity and developing bias voltage in accordance therewith.

Abstract: The image density adjustment method for use in electrophotography in which, when the image density of a copied image is decreased below a standard image density, the development bias-potenial is increased while the exposure to be applied to a photoconductor is kept constant. When the image density of a copied image is increased above the standard image density, the exposure is decreased while the development bias voltage is kept constant. Thus, the image density of a copied image can be adjusted as desired to minimize the effect of light fatigue of the photoconductor.

Abstract: An imaging optical system (34) scans an original document (58) and radiates a light image thereof onto a photoconductive drum (31) to form an electrostatic image which is developed to form a toner image. A first pulse generator (62) is driven synchronizingly by rotation of the drum (31) to produce first pulses. A second pulse generator which may include a clock pulse generator (19) for a microcomputer (12) used to control the operation of the copying machine (11) and a frequency divider (78) produces second pulses having a frequency typically ten times that of the first pulses. First and second counters (71), (79) count the first and second pulses respectively, the second counter (79) being reset by each of the first pulses. A sensor (83) senses a predetermined scan position of the optical system (34) and generates an electrical signal.

Abstract: A plurality of electrostatic copying machines (12), (13), (14), (16) are interconnected by bus lines (19), (21), (22). Each copying machine (12), (13), (14), (16) is provided with a sensor unit (23) for sensing various status parameters of the copying machine (12), (13), (14), (16) such as whether the copying machine (12), (13), (14), (16) is available for use, the copy sheet size, the number of copies made, the number of copy sheets remaining, etc. Each copying machine (12), (13), (14), (16) is further provided with a display unit (17) for displaying the status parameters of all of the copying machines (12), (13), (14), (16). A microcomputer (31) is provided at one of the copying machines (12) for storing and processing the status parameters and producing a hard copy.

Abstract: The apparatus comprises a projection optical system and a copying system. The projection optical system can project an image of an original either onto a screen or to an exposing position of the copying system by switching between two positions. The copying system comprises a plurality of chargers providing different charging conditions in accordance with the types and sizes of copy sheets, by utilizing a change-over switch. A plurality of switches adapted for use with copy sheets of different lengths are arranged along the path of movement of a sheet of paper and, when the switch corresponding to the particular length of copy sheet desired is actuated, the movement of the sheet of paper is stopped, so that the central portion of the copy sheet can be brought into alignment with the optical axis for exposing at all times regardless of the difference in the length of copy sheets.

Abstract: In electrophotographic apparatus for producing positive copies of both positive and negative originals with toner of one polarity by establishing and developing an electrostatic latent image on a light-sensitive member that is precharged to a first polarity for positive originals and to the opposite polarity for negative originals, wherein means are provided for exposing the precharged member to an optical image of the original and for controlling the exposure by varying the amount of light used, a two-position changeover switch for reversing the operation of the exposure controller depending on whether the original is positive or negative. This changeover switch, and also a switch for reversing the charging polarity of means for precharging the light-sensitive member, may be controlled by photoelectric means for determining whether the original is positive or negative by sensing the optical density of a marginal portion provided on the original.