Abstract: The present invention provides an image forming apparatus having image signal discrimination device for discriminating whether an image density signal belongs to a line image portion or a natural image portion including a halftone image and outputting a discrimination signal, first image density conversion device having a first conversion property for converting the image density signal to a conversion signal and outputting the conversion signal, second image density conversion device having a second conversion property which is different from the first conversion property for converting a range of the image density signal corresponding to a low density portion to a conversion signal indicating a value within a range in which an image is not developed and outputting the conversion signal, selection device for alternately selecting the first and second image density conversion device with a predetermined period, pulse width modulation device for modulating pulse widths of the conversion signals output from the

Abstract: A method and apparatus for producing a multi-image or multi-color image utilize an intermediate transfer member that is a single layer of fluorocarbon elastomer. The method produces high quality images that do not suffer from image or color shifting or degradation. The single layer intermediate transfer member can contain different zones of electrical properties within the single layer.

Abstract: The present invention provides a process cartridge mountable to an image forming apparatus. The cartridge includes an image bearing member, a processor for acting on the image bearing member, a driving force receiver provided at one end of the image bearing member, a protection member shiftable between a protection position to protect the image bearing member and a retract position, a first projection provided on the side of a toner containing portion, a guide member protruded in the direction perpendicular to the moving direction of the image bearing member, a second projection protruded in the moving direction of the image bearing member, and a third projection protruded from the protection member.

Abstract: In a multi-color imaging apparatus utilizing a recharge step between two image creation steps for conditioning a charge retentive surface pursuant to forming the second of the two images, a corona generating device is used to both charge the toned and untoned areas of the charge retentive surface, and to keep wrong-charge toner developed in the background areas at a charge level distinct from the toner developed in the image areas, so that the wrong-charge background toner does not transfer to a support substrate with the image.

Abstract: A sensor having a shutter mounted to a segment of a molded hinge for movement within a housing in opposition to a light path between an LED and photodetector is described. The molded arm includes a hinge and the segment of the molded hinge extends outside the housing connected to the elongated arm. One end of the elongated arm engages a moving photosensitive surface and deviations of the edge position of the photosensitive surface rotate the shutter in relation to the light path between the LED and photodetector for tracking the edge position of the moving photosensitive surface by providing signals representing shutter position.

Abstract: Disclosed is an image processing apparatus by which a first image corresponding to first image information and a second image corresponding to second image information are superimposed one on the top of the other, the apparatus comprising a scanning device for scanning a document line by line to output the first image information; a composing device for composing the first and second image information so that the first and second images are superimposed one on the top of the other; a detecting device for detecting changes of the scanning speed in a direction perpendicular to the lines; and a controlling device for so controlling the composing device that the relative position of the second and first images in the direction are adjusted line by line in accordance with the results detected.

Abstract: An image forming apparatus from which an external memory unit storing an image formation mode is arbitrarily detachable, has an image forming unit for forming an image on a recording medium in a desired image formation mode, an inserting unit for inserting the external memory unit, a determining unit for determining realizability/unrealizability of the image formation mode stored in the external memory unit inserted in the inserting unit, and an alarming unit for alarming the determination result from the determining unit.

Abstract: An image fixing apparatus includes a conductive fixing film, a pair of electrodes contacting the conductive fixing film, a supporting element supporting the electrodes, a pressing roller located on a side of the conductive fixing film opposite to the supporting element and having an outer elastic layer. The conductive fixing film is moved at a constant speed so that a transfer material having an unfixed toner image is nipped between the conductive fixing film and is moved. The transfer material is thus subjected to a heating and fixing operation. A thermometer detects a temperature of the electrode or one part of the supporting element. A memory stores a data-table having a relation between a power supply to the electrodes and a temperature of the thermometer. A control circuit both determines a suitable supply power from the data-table and the temperature detected by the thermometer, and controls the supply power supplied to the electrodes.

Abstract: An electrostatographic printer includes an imaging station for forming a latent electrostatic image on the surface of a drum, a toner development station for developing the latent image to form a toner image, and a toner transfer station for transferring the toner image onto a moving web. An image-fixing station for fixing the toner image on the web includes two pairs of radiant heat sources, the peak energy output wavelength of which lies in the non-visible part of the spectrum. The radiant sources may be located in hingedly mounted pairs of housings in such a manner that the housings may be moved into a closed position to shield the radiant sources from the web when the speed of movement of the web falls below a predetermined value. Thus, damage to the web when movement of the web stops is avoided.

Abstract: A sheet feed mechanism utilizing a continuous form sheet, with a plurality of equally spaced sprocket holes formed on both side edges thereof in the direction along a straight sheet feed path, is fed between a photoconductive member and transfer member. Each side of the sheet feed mechanism includes an endless tractor belt looped between two feed rollers disposed upstream and downstream of the transfer member, respectively. In one aspect, engaging pins are provided on the circumferential surface of the feed rollers and engaging holes on the tractor belt spaced at the same interval as the holes of the continuous form sheet, to feed the sheet by engagement of the engaging pins and the sprocket holes through the engaging holes. In another aspect, the endless belt is provided with the engaging pins and a regulation member for moving the tractor belt such that a portion of its upper part is separated from the photoconductive member.

Abstract: An image-forming apparatus for forming an image, especially a halftone image, by using a photosensitive member, having a charging member for charging the photosensitive member, a mechanism for relatively moving the charging member and the photosensitive member, a voltage source for applying an oscillatory voltage to the charging member such that a Vp/f ratio is about from 0.08 to 0.42, wherein the Vp represents a relative moving speed between the charging member and the photosensitive member and the f represents a frequency of the oscillatory voltage, an exposing member for exposing the charged photosensitive member to form an electrostatic latent image, and a developing unit for developing the electrostatic latent image.

Abstract: An electrophotographic single-component developing device including a development roller; a toner storing portion provided in parallel relationship to an axis of the development roller, for storing a single-component toner; and a toner feeding unit provided in the toner storing portion, for feeding the single-component toner stored in the toner storing portion in a direction parallel to the axis of the development roller and supplying the single-component toner to the development roller. The toner feeding unit has a spiral agitator formed from a wire. Accordingly, the ability of toner feed along the development roller and the ability of toner supply to the development roller can be improved without deterioration of the toner.

Abstract: A developer recycling system is provided for replenishing a fresh developer to a developing device of an image forming apparatus and collecting it after use. A developer cartridge applicable to the system is also provided. When the fresh developer is replenished from the cartridge to the developing device, a developer existing in the developing device overflows in an amount corresponding to the replenished developer. The developer overflown the developing device is recirculated to the cartridge and reused.

Abstract: The present invention is directed to an image density control device in an image formation apparatus where a pattern of reference density on a sample original is exposed to light from an exposing light source to image the pattern on photoconductor, density of the resultant toner image is detected by a reflection-type photosensor, and parameters on image density are adjusted based upon results of detection by the reflection-type photosensor. In the image density control device in the image formation apparatus, the sample original is mounted on a cabinet of the image formation apparatus so that a distance from the exposing light source in illuminating the pattern of the reference density to the pattern of the reference density can be adjusted.

Abstract: A development station for toning electrostatic images includes a particle removing device positioned adjacent an applicator. A variable bias is applicable to the particle removing device for periodically removing carrier from the applicator for disposal. Carrier is periodically added to the station during replenishment of toner. The particle removing device can also be biased to remove toner instead of or in addition to removing carrier to control conditions of excess toner concentration.

Abstract: The present invention provides an electrophotographic photosensitive member comprising a photosensitive layer formed on an electroconductive support, and a surface layer formed on the photosensitive layer, wherein said photosensitive layer contains a charge-generating substance, a charge-transporting substance, and a binder resin, and the surface layer contains a fluorine-atom-containing particulate resin, a charge-transporting substance, and a binder resin, wherein the binder resin in the surface layer and the binder resin in the photosensitive layer are composed of the same constitution components, the binder resin in the surface layer has a number-average molecular weight of from 50,000 to 160,000 and the binder resin in the photosensitive layer having a number-average molecular weight of from 10,000 to 50,000, and the number-average molecular weight of the binder resin in the surface layer is two or more times larger than that of the binder resin in the photosensitive layer.

Abstract: In a transfer unit of a non-contact roller transfer method, both ends of a transfer roller shaft are supported independently of each other so as to be movable upward and downward, and an upward pushing force is provided thereto. A gap maintaining roller provided in the vicinity of each end portion of the transfer roller shaft is always in contact with the surface of a photoreceptor drum so that the gap between the surface of the photoreceptor drum and the transfer roller is maintained uniform and fixed. Further, both ends of a pre-transfer guide for guiding the sheet to the photoreceptor drum are supported in a manner such that the movement of each end accords with the movement of the end portion of the transfer roller, so that the distance between the photoreceptor drum and the pre-transfer guide is maintained uniform and fixed.

Abstract: A developing method using a compact machine such as a copying machine for personal use, etc., employs a two component-type magnetic developing agent with small diameter photosensitive drum and small diameter developing sleeve. In order to eliminate toner falling from the drum and/or sleeve to increase toner transfer efficiency and reduce fogging, the developing agent conveying sleeve is provided with a curvature (mm.sup.-1) of from 0.2 to 0.05. The toner is specifically designed for use in the method and includes magnetic fine particles having a saturation magnetization of not smaller than 70 emu/g and hydrophobic fine silica particles added to fixing resin particles containing a coloring agent.

Abstract: An image forming apparatus includes a microcomputer which controls components for executing an image forming operation, and sends a signal to a supervising portion when no abnormality occurs in itself. The supervising portion includes a watch-dog timer, and sends a reset signal to the microcomputer when the signal from the microcomputer is not continuously inputted for a predetermined time period or more. Accordingly, the microcomputer becomes in a reset state, and the image forming operation is stopped. A flag is not set until a predetermined time period elapses from a time that the reset signal is inputted, and therefore, the image forming operation is inhibited for the predetermined time period.

Abstract: An improvement for a container disposed in a printing machine is disclosed. The container is adapted to dispense toner and capable of maintaining a quantity of toner therein. The improvement includes a sensor for sensing that the quantity of toner in the container is less than or equal to a predetermined quantity. The sensor is located in and isolated from the container by an isolating arrangement, the isolating arrangement preventing forces applied to the container from being transmitted to the sensor. In the preferred embodiment, the isolating arrangement includes a mechanism for damping movement of the sensor with respect to the container to decouple substantially the sensor from the container.