Abstract: An image forming apparatus using an electrophotographic process is disclosed which measures the resistance of a page onto which an image is to be formed and optionally also measures the humidity of ambient environment. A controller controls image forming conditions, such as a development condition or a transfer condition, according to the measured resistance and/or the measured humidity.

Abstract: An image forming apparatus using an electrophotographic process including a photoconductor, a development device, and a transfer device, a measuring device measures an electrostatic capacitance between said photoconductor and said transfer device in predetermined conditions while a standard toner image is formed. Humidity of ambient environment is also measured. Then, a controller controls image forming conditions such as a development condition or a transfer condition according to the measured electrostatic capacitance and the humidity. Alternately, a resistance of the paper is measured, and a controller controls image forming conditions according to the measured resistance. In a still different way, an amount of toner charges of a standard toner image is measured, and a controller controls image forming conditions according to the measured amount of toner charges.

Abstract: In order to control development condition and/or transfer condition for stable image forming, toner patterns of the same density are formed on a photoconductor and are transferred onto a paper or the like while changing the transfer current. Then, the transfer efficiencies of the toner patterns are measured. Other characteristics such as the resistance of the paper and charge of toners may also be monitored. Then, the development condition and/or transfer condition is controlled according to the detected data.

Abstract: In an electrophotographic copying machine, image quality is improved by suppressing phenomena such as narrowing and thickening of a linear image or discharge noises in a photograph image due to anomalies on transfer of a toner image. For example, a document type is discriminated and when a transfer brush is used for transfer, transfer current and pretransfer erasing are controlled according to the type of document image. The pretransfer erasing is controlled in various following situations: Bi-level exposure method or multi-level exposure method, edge emphasis, photoelectric efficiency, the surface potential of the photoconductor, and position of a developing device.

Abstract: An image forming apparatus gets information on the thickness of the photosensitive layer by using the image transfer power source and transfer brush, and controls the contact position of the transfer brush on the paper carrying belt based on the thickness information, so that in case the photosensitive layer wears thin partially due to the long-term use, the apparatus increases in compensation the impedance of the carrying belt in its section from the image transfer zone to the contact position of the transfer brush. The apparatus may be designed to use selectively multiple transfer brushes having different impedances, instead of the position control of one transfer brush.

Abstract: A pressing force adjusting mechanism decreases a pressing force of a pressing member 16 when a leading edge or a rear edge of a transfer material P passes through a transfer point P1 based on the detection signals from a transfer material position sensor 57 and/or a transfer material type sensor 58.

Abstract: An image forming apparatus which sequentially transfers and superimposes sequentially formed electrostatic latent images onto a sheet wound around a sheet support. The image forming apparatus have either a photoconductor where the electrostatic latent images are sequentially formed on the surface or a plurality of photoconductors where the electrostatic latent images are formed respectively and sequentially. The quantity of print dot misregister is detected by forming reference patterns on a sheet and by reading the formed reference patterns. The rotational speed of conveying rollers for delivering a sheet to the sheet support is switched over in response to the quantity of the print dot misregister. The rotational speed of the conveying rollers can also be switched over in response to the thickness of a sheet. In the case that the image forming apparatus is a full-color copying machine, the electrostatic latent images are of four types for cyan, magenta, yellow and black.

Abstract: In an electrophotographic image forming apparatus including a photoconductive drum, the photoconductive drum is electrically charged by a corona charger, and light corresponding to an image is projected onto the photoconductive drum by an exposure optical system, thereby forming an electrostatic latent image thereon. Thereafter, the formed electrostatic latent image is developed with toner by a developing unit to form a toner image thereon, and then the toner image is transferred onto a sheet of paper. There is further provided a voltage sensor for detecting a surface voltage at at least one position of the photoconductive drum. An operation value of at least one of the corona charger, the exposure optical system and the developing unit is adjusted by an adjustment controller based on the surface voltage detected by the voltage sensor at a timing between respective image forming processes when an image forming process is continuously repeated a plurality of times.

Abstract: A digital half-tone image is reproduced by exposing a photoconductor by modulating the intensity of laser beam. In order to correct the effect of the size of laser beam on the gradation characteristic, the surface potential of the photoconductor is detected under various conditions. The sensitizing potential and the sensitivity of the photoconductor are corrected according to the measured values for stabilizing the gradation potential. Then, the beam size is corrected according to the surface potential or the amount of adhered toners detected under prescribed conditions, without detecting the beam size.

Abstract: In forming a digital image on the photoconductor wherein the intensity of the laser beam is modulated according to multi-level image data, a standard toner image is formed at an intermediate intensity at which the reproduced image density is not affected by the beam size, and the toner density is detected. On the other hand, the size of the beam for exposing the photoconductor is measured. Then, the gradation characteristic is controlled according to the toner density and the beam size. Thus, the effect of the beam size on the gradation characteristic is corrected.

Abstract: In an electrophotographic image forming apparatus, a charger sensitizes the photoconductor at a desired initial potential and the photoconductor is exposed to form an electrostatic latent image, which is developed by a developer to form a toner image. A gradation correction table on the relation of the input image signal to the exposure amount is provided in a memory, and it is amended by adding a common amendment value to the image density signal in the gradation correction table. The common amendment value is determined according to the density of a standard toner image. If a plurality of gradation correction tables are stored in a memory, one of them is selected according to the output voltage of the charger or the bias potential of the developer. The selected gradation correction table is amended according to the surface potential of the photoconductor, the temperature of the photoconductor or the humidity of the photoconductor.

Abstract: In an image forming apparatus with use of electrophotographic process, a plurality of toner images are formed on a photoconductor by changing stepwise a predetermined operating parameter such as light intensity of laser beam or the grid potential of sensitizing charger, and the densities of the toner images are measured. Thus, the value of the operating parameter is determined which corresponds with the smallest non-zero toner density among the measured densities. When an image is formed on the photoconductor, for example the gamma table is corrected according to the determined minimum light intensity.

Abstract: In an image forming apparatus for forming an image on a sheet of paper, including an image forming device for forming a reference toner image having a predetermined density on an image retaining member. A first detector detects a density of the reference toner image formed on the image retaining member and outputs first density data for representing the detected density thereof, and then, the reference toner image formed on the image retaining member is transferred onto a sheet of paper. On the other hand, a second detector detects a density of the reference toner image transferred on the sheet of paper and outputs second density data for representing the detected density thereof. Further, a controller automatically adjusts an image density of an image formed on a sheet of paper so as to obtain a predetermined image density by controlling operation conditions of the image forming device based on the first and second density data respectively outputted from the first and second detectors.

Abstract: A distributing connector includes a collective receptacle having a plurality of unit receptacle connectors, and plug connectors to be fitted in the unit receptacle connectors, respectively. The distributing connector includes a U-shaped plug connector receiving cover for receiving bases of the plug connectors, and a U-shaped back cover for receiving wires. The receiving cover has openings for receiving fitting portions of the plug connectors arranged correspondingly to the unit receptacle connectors of the collective receptacle and back cover mounting ribs along outer edges of an opening of the U-shaped cover. The back cover has grooves along outer edges of an opening of the U-shaped back cover for receiving said back cover mounting ribs of the plug connector receiving cover and plug connector retaining ribs along inner edges of said opening of the U-shaped back cover.