Abstract: An exposure device having an array of a plurality of light emitting elements composed of at least an anode layer, a cathode layer and one or more organic compound layers interposed between the anode layer and the cathode layer all of which are formed on a substrate. In the exposure device, the quantity of light emitted from each light emitting element is made uniform by controlling the light emitting area of each light emitting element. Therefore, the exposure device eliminates differences in the quantity of emitted light among the plurality of light emitting elements without using a special drive circuit.

Abstract: An electrophotographic apparatus includes an electrophotographic photosensitive member; a charger for charging the electrophotographic photosensitive member including a charging member supplied with a voltage and disposed in contact with the photosensitive member so as to form a nip with the photosensitive member to charge the photosensitive member; an exposure device; a developing device; and a transfer device. The photosensitive member includes a surface layer containing a charge-transporting material having an oxidation potential of 0.4-1.0 volt. Charging promoter particles are present at the nip between the photosensitive member and the charging member to injection-charge the photosensitive member. Because of the selection of the charge-transporting material and the presence of the charging promoter particles, the photosensitive member can be effectively injection-charged.

Abstract: Provided is a light emitting apparatus capable of preventing light emitting elements made of an organic compound from being affected by moisture in an ambience, thereby increasing their lifetime, and suitably applicable to an exposure section of the electrophotographic method. Temperature sensors are set next to a light emitter array which is an array of many light emitting elements made of the organic compound. A drive control unit of the array is composed of CPU, ROM, RAM, and I/O ports. The CPU carries out control of each unit according to input data of image information etc. and also carries out pre-heat control for the light emitting elements. The temperature sensors detect the temperature of the light emitting elements and the CPU, receiving their detection output, turns the light emitting elements or a heating element provided separately, on and off so that a detected temperature value becomes a predetermined value in a waiting state without the input data.

Abstract: The exposure device of an image forming apparatus includes a light-emitting device array having light-emitting devices; a switching device array including switching devices connected to the light-emitting devices, the switching device array being divided into a plurality of groups; a first line group for connecting commonly to first terminals of switching devices of each of the groups; a second line group for connecting commonly to second terminals of switching devices of each of the groups; and a circuit for performing simultaneous light emission of the light-emitting device array to expose the photosensitive member.

Abstract: A charging apparatus includes a charging member, to which a voltage is applicable, for charging a member to be charged; the charging member including: a flexible member for forming a nip with the member to be charged, wherein the flexible member is moved with a peripheral speed difference between surfaces of the flexible member and the member to be charged at the nip; and electroconductive particles in the nip.

Abstract: An image forming apparatus includes an image bearing member with a recirculatively movable peripheral surface; and a device for forming electrostatic latent images on the peripheral surface of the image bearing member, the device including a charging member to which voltage is applicable to charge the image bearing member. The charging member includes a flexible member capable of forming a nip between itself and the image bearing member; a developer for developing the latent image with the use of developer composed of toner particles and electrically conductive particles. The developer is capable of cleaning the residual toner particles from the image bearing member. The electrically conductive particles transferred onto the image bearing member by the developer are delivered to the nip by the image bearing member. The flexible member is moved so that it maintains a peripheral velocity difference relative to the image bearing member.

Abstract: A light emitting apparatus including a photosensitive member and an exposure device including a light emitting device array made up of a plurality of light emitting devices arranged in a direction of main scan across a moving direction of the photosensitive member and a switching device array made up of a plurality of switching devices arranged and connected to the light emitting devices in one-to-one relation. The switching device array is divided into a plurality of groups, a first group of leads connected in common to first terminals of the switching devices for each of the plural groups of switching devices, a second group of leads connected to second terminals of each of the switching devices, and a third group of leads, each of the third group of leads connected to third terminals of each switching device in a respective group of switching devices.

Abstract: A charging device includes a charging member to which a voltage is applicable to charge a member to be charged, the charging member including a flexible member for forming a nip with the member to be charged, wherein the flexible member is moved to provide a speed difference between a surface of the member to be charged and a surface of the flexible member; wherein not less than 10.sup.2 /mm.sup.2 electroconductive particles are provided in the nip.

Abstract: An image forming apparatus which includes a plurality of recording units for forming images having different colors at respective recording positions on the same recording material, each of the plurality of recording units including a photosensitive member, and an exposure unit for exposing the photosensitive member with light. At least one of the plurality of recording units has an exposure unit which includes a plurality of arrays of light-emitting elements. A misregistration detector detects misregistration information for a predetermined image formed by each of the plurality of recording units, and a selector selects one of the plurality of arrays of light-emitting elements for use during image formation based on the misregistration information obtained from the misregistration detector.

Abstract: The present invention provides an image forming apparatus comprising a photosensitive member, scan means including light emitting elements for emitting laser beam to scan the photosensitive member, and control means for controlling the illumination of the light emitting elements. Wherein, when a shifting speed of the laser beam on the photosensitive member is v, a length of one side of a pixel is L and a maximum light emitting time of the light emitting element for each pixel is t, the control means controls the light emitting elements to satisfy a relation of t<L/v.

Abstract: An image forming apparatus has an electrophotographic photosensitive member with a support, a photosensitive layer with a thickness (T), a charging subunit, an exposure subunit, a developing subunit, and a transfer subunit. The exposure subunit illuminates the charged photosensitive member with a light beam having a spot area (S), such that the product S.times.T is 5,000-12,000 .mu.m.sup.3.

Abstract: A color image processing apparatus includes arranging means for arranging intervals between dot positions on a scanning line at which dots are formed, and shifting means for shifting the dot positions on the scanning line by a shifting amount. At least one of the intervals and the shifting amount for a first color component are different from an interval and a shifting amount of a second color component. The processing apparatus also includes control means for controlling the arranging means and the shifting means so that n (n.gtoreq.3) adjacent dot positions at which the first color component and the second color component overlap correspond to vertices of a substantially regular polygon having n vertices.

Abstract: An electrophotographic system is constituted by an electrophotographic photosensitive member, a charger for charging the photosensitive member to a potential, and an illuminator for illuminating the charged photosensitive member with a light beam to form an electrostatic image thereon. The electrophotographic photosensitive member has a potential-exposure energy characteristic providing an induction energy and a gamma valve varying depending on an electric field intensity induced by the charged potential. The electrophotographic system further includes a controller for controlling the charged potential on the photosensitive member corresponding to resolution and gradation data of an original, so as to optimally reproduce the resolution and gradation, as desired, of the original.

Abstract: A developing method includes forming a magnetic field between an image bearing member bearing an electrostatic image and a developer carrying member carrying a developer comprising toner particles and carrier particles; and contacting chains of carrier particles formed on the developer carrying member to the image bearing member; wherein an absolute value of an intensity of a magnetic field in a movement direction of the developer carrying member over the entire portion of the developer carrying member at a position where the carrier is contacted to the image bearing member is positive.

Abstract: A color image processing apparatus for sequentially inputting image data which corresponds to each of a plurality of color components in units of pixels of a predetermined quantity, delaying, with respect to a reference phase, at least the first color component or the last color component and sequentially forming image in the units of pixels of a predetermined quantity in accordance with the delay.

Abstract: A developing method for developing an electrostatic image on an image bearing member with a two-component developer includes the steps of bearing a developer containing toner particles and carrier particles on a developer bearing member to a contact region formed between the developer bearing member and an image bearing member bearing an electrostatic image thereon, and rubbing the image bearing member with the magnetic brush with a contact pressure equal to 0.7 gf/cm.sup.2 or less.

Abstract: An image forming apparatus includes an image bearing member; a latent image forming device for forming on the image bearing member a dot distribution electrostatic latent image in accordance with image signals corresponding to an object image; a developing device for developing the latent image formed on the image bearing member by the latent image forming device, in a developing station and by a developer containing toner and magnetic carrier; wherein the developing device includes a developer carrying member for carrying and conveying the developer to the developing station, and a magnetic field generating device provided within the developer carrying member, for forming a magnetic brush of the developer and contacting the magnetic brush to the image bearing member; and wherein a degree .sigma.d (emu/cm.sup.

Abstract: An image processing apparatus binarizes input multi-level pixel data by changing the same either to the minimum density data corresponding to white or to a minimum reproducible density data corresponding to the minimum density level reproducible by an image forming apparatus such as a printer, when the density defined by the input multi-level pixel data is of such a low level that it cannot be reproduced by the image forming apparatus. Error incurred by the binarization is reflected in the succeeding binarizing process so that the density of the whole image is preserved, whereby an image with a highlight portion can be recorded with reduced degradation of the image quality at the highlight portion.

Abstract: A color electrophotographic apparatus includes a photosensitive member movable along an endless path; a charger for charging the photosensitive member; a scanning optical system for scanning the photosensitive member having been charged by the charger with information light responsive to color signals; a controller for controlling an exposure amount of the photosensitive member by the scanning optical system; a transfer device for simultaneously transferring toner images formed superposedly on the photosensitive member; wherein the controller controls the optical scanning system in consideration of transmissivity of the light through the toner.

Abstract: An image forming apparatus wherein a laser beam produced by a laser source is imaged through an imaging optical system on an image bearing member as a beam spot. The beam spot scans the image bearing member in a main scan direction. The laser source is rendered on and off to form an image with picture elements. The laser driving pulse width per picture element is changed in accordance with the image density of the image to be formed, so that the tone gradation of the image is provided on the image bearing member in accordance with the pulse width. The size of the spot measured in the main scan direction (1/e.sup.2 diameter) is not more than 0.7 times of the size of the picture element measured in the main scan direction.