Abstract: In an image forming apparatus, an electrostatic latent image is reverse-developed by a developing device with a development bias applied, through conveying a two-component developer layer containing toner particles having a volume-average particle diameter of 3 to 5 &mgr;m by a developer carrying member rotatably provided, a developed toner image is transferred onto a recording medium or an intermediate transfer body, and untransferred toner particles remaining on an image forming body having passed a transfer region are removed by a cleaning member provided in pressure contact with the surface of the image forming body. The length in an axis direction of the image forming body of an useless toner image formed on the image forming body at the starting time and the ending time of an image formation sequence denoted by L, the total charge quantity of the toner particles making up the useless toner image is 0.04L &mgr;C or less.

Abstract: An image forming apparatus is provided for obtaining excellent developing properties using toner with small particle diameters and for forming high-quality visual images. In the developing device of the image forming apparatus, a two-component developer is used which satisfies conditions that volume mean particle diameter dt of the toner is 3˜5 &mgr;m (Condition 1), volume mean particle diameter dc of the carrier is 5dt˜10dt (Condition 2), and a weight ratio Rw of the toner and the carrier is 1.6 (dt/dc)×(&rgr;t/&rgr;c)˜2.4 (dt/dc)×(&rgr;t/&rgr;c) (Condition 3, where &rgr;t and &rgr;c are density of the toner and the carrier, respectively). A main magnetic pole of a rotary sleeve is arranged in the vicinity of the closest position of the rotary sleeve and the image forming body, and the closest distance D between the rotary sleeve and the image forming body satisfies a condition that D is 0.5 H˜0.8 H for the free tip height H of a magnetic brush of the main magnetic pole.

Abstract: In a fixing apparatus for fixing a toner image on a transfer material by applying heat and pressure to the transfer material, the fixing apparatus includes: a roll-shaped rotary member for applying heat, including a ray radiating device for radiating a ray generated by a ray generating source provided inside the ray radiating device; a cylindrical ray-transmitting base member through which the ray generated by the ray generating source is transmitted, being arranged around the ray radiating device; a resilient layer; and a ray absorbing layer provided outside the resilient layer for absorbing the ray generated by the ray generating source. The following condition is satisfied, K1>K2 where K1 (J/cm·s·K) represents thermal conductivity of the ray-transmitting base member and K2 (J/cm·s·K) represents thermal conductivity of the resilient layer.

Abstract: In an image forming apparatus, in which toner images formed on an image forming body are formed on double sides of a transfer material, a writing of an image on the image forming body by a writing device according to image data for an intermediate transfer body is conducted before a feeding of the transfer material is started.

Abstract: The present invention concerns a duplex image forming apparatus, which can form images on both sides of a transfer sheet by employing an intermediate transfer element. The duplex image forming apparatus includes an image bearing member; a toner image forming section to form a toner image on the image bearing member; an intermediate transfer element, shaped like a belt, to bear the toner image transferred from the image bearing member and to convey a transfer sheet; a transfer sheet charging device to apply a bias voltage onto the transfer sheet at the charging position, so that the transfer sheet adheres onto the intermediate transfer element; a first transfer device to transfer the toner image onto the transfer sheet or the intermediate transfer element; a second transfer device to transfer the toner image borne on the intermediate transfer element onto the transfer sheet; and a control section to control a transfer current or a transfer voltage applied to the first transfer device.

Abstract: There is described a fixing apparatus, for fixing a toner image on a transfer medium by applying heat and pressure onto the transfer medium, which includes a heat ray irradiating device to irradiate heat rays and a pair of fixing rollers being hollow cylinders. The fixing roller includes a base body being a hollow cylinder and capable of transmitting the heat rays irradiated from the heat ray irradiating device, a heat-resistant resin layer formed on an outer surface of the base body and being capable of transmitting the heat rays irradiated from the heat ray irradiating device, and a heat ray absorptive layer provided on the heat-resistant resin layer.

Abstract: In a fixing apparatus for fixing toner images on a transfer material upon which toner images have been placed by applying heat to the transfer material, the fixing apparatus includes: a roll-shaped rotary member for applying heat to the transfer material upon which toner images have been placed, the roll-shaped rotary member including a cylindrical ray-transmitting base member, and a ray absorbing layer for generating heat onto the transfer material upon which toner images have been placed so as to fix the toner on the transfer material, the ray absorbing layer, provided on an outer side of the ray-transmitting base member; a ray irradiating device for irradiating ray to the ray absorbing layer, the ray irradiating device provided inside the cylindrical ray-transmitting base member; bearing member for rotatably supporting the roll-shaped rotary member; flange members provided on both ends of the ray-transmitting base member; and an elastic covering member provided between the flange member and the roll-shaped

Abstract: A two-sided image forming apparatus includes: an image carrying member; a toner image forming device for forming a toner image on the image carrying member; a belt-shaped intermediate transfer body for conveying a transfer material, having a volume resistivity R (&OHgr;·cm) wherein the following expression is satisfied, 109≦R<1012; a primary transferring device for transferring the toner image on the image carrying member onto the intermediate transfer body or a front face of the transfer material; and a secondary transferring device for transferring the toner image on the intermediate transfer body onto a rear face of the transfer material. The following expressions are satisfied, 0.2≦I(1B)/V≦0.7 and 0.6×I(1B)≦I(2)≦1.

Abstract: In an image forming apparatus, a document image is read by an image scanner and image data are applied with image processing and stored in a memory. An image correction device corrects the image data with a different correcting condition depending on whether the image data are used for a toner image on the obverse side of the sheet or for a toner image on the reverse side of the sheet. A fixing device fixes the toner images on the obverse side and the reverse side of the sheet simultaneously.

Abstract: A fixing apparatus for fixing toner images on a transfer material by applying heat on the transfer material, the fixing apparatus includes: a roll-shaped rotary member for applying heat, including a cylindrical ray-transmitting base member, and a ray absorbing layer for generating heat, provided on an outer side of the ray-transmitting base member; a ray irradiating device for irradiating ray, provided inside the cylindrical ray-transmitting base member; and flange members provided on both ends of the ray-transmitting base member, and each of the flange members being joined with the ray-transmitting base member through a joining elastic layer.

Abstract: An image forming apparatus includes a reversing unit for reversing a two-sided document and placing the document on a platen, a reading unit for reading image data of either a front or back side of the document placed on the platen by the reversing unit, and at least one of: (i) a first detecting/setting unit for providing first information representing a position on which a binding margin of the document is located and a direction in which a top or bottom portion of the document is directed, and (ii) a second detecting/setting unit for providing second information representing a position on which a binding margin of an image to be printed is located and a direction in which a top or bottom portion of the image to be printed is directed.

Abstract: In a color image forming apparatus provided with a toner image forming device for forming a color toner image on a transfer sheet; and a pair of cylindrical fixing rollers for nipping the transfer sheet bearing the color toner image formed by the toner image forming device therebetween and for fixing the color toner image on the transfer sheet; at least one of the pair of cylindrical fixing rollers including a heat ray irradiating device, a cylindrical light transmitting base member at an inside of which the heat ray irradiating device is provided, an elastic layer provided on the cylindrical light transmitting base member, and a heat ray absorbing layer provided on the cylindrical light transmitting base member and for absorbing and substantially shutting the heat ray passing the cylindrical light transmitting base member.

Abstract: An image forming apparatus includes: a first image carrier for carrying a toner image formed by an toner image forming device; a second image carrier for carrying thereon the toner image transferred from the first image carrier, and for transferring a transfer sheet thereon; a first transfer device for transferring the toner image carried on the first image carrier onto the second image carrier or a front side of the transfer sheet; a second transfer device for transferring the toner image carried on the second image carrier onto a back side of the transfer sheet; a fixing device for fixing the toner image transferred on the transfer sheet, wherein the second image carrier has a curvature portion at an edge thereof facing the fixing device; and a conveyance section provided between the curvature portion and the fixing device, having a claw member provided adjacent to the curvature portion for lifting a leading edge of the transfer sheet conveyed along the curvature portion.

Abstract: An image forming apparatus includes a first image carrier for carrying a toner image formed thereon; a second image carrier for carrying the toner image transferred from the first image carrier and for conveying a recording sheet; a first transfer device for transferring the toner image carried on the first image carrier onto the second image carrier or an obverse side of the recording sheet; a second transfer device for transferring the toner image carried on the second image carrier onto a reverse side of the recording sheet and a fixing device for fixing the toner image transferred on the recording sheet. The second image carrier is provided with a curved portion at an end on a side of the fixing device, at which the recording sheet conveyed by the second image carrier is bent toward the reverse side of the recording sheet so as to separate the recording sheet from the second image carrier.

Abstract: An image forming apparatus includes: an image forming body; an intermediate transfer body for carrying a toner image transferred from the image forming body and conveying a transfer material thereon; a first transfer device for transferring the toner image on the image forming body onto the intermediate transfer body or a front side of the transfer material; a second transfer device for transferring the toner image on the intermediate transfer body onto a back side of the transfer material; and a fixing device for fixing the toner image transferred on the transfer material. The second transfer device includes a corona discharger having a discharging electrode and a shielding member for shielding an electric field when the discharging electrode discharges, and the shielding member has a circulation hole through which air flows along an outer circumferential surface of the intermediate transfer body in a conveyance direction from upstream to downstream of the transfer material.

Abstract: In an image forming apparatus provided with a first image carrying member; a belt-shaped second image carrying member onto which a toner image is transferred from the first image carrying member; a pair of rotatable fixing members forming a nip region for fixing the toner images transferred on the both sides of the sheet; a conveying device for guiding the sheet separated from an end of the belt-shaped second image carrying member to the pair of rotatable fixing members, when the sheet is nipped and conveyed through the nip region of the pair of rotatable fixing members, the belt-shaped second image carrying member and the pair of rotatable fixing members are arranged such that the sheet is conveyed so as to form a loop protruding from a line connecting the entrance of the nip region and the end of the belt-shaped second image carrying member.

Abstract: In an image forming apparatus provided with an image carrying member, a toner image forming device, an intermediate image carrying member, a first transfer member, and a second transfer member, toner images are formed on both sides of a sheet. The toner images on the both sides of the sheet is fixed by a fixing device having a heater and a pair of fixing rollers. A detecting device detects at least one of a temperature of the fixing members, a material of the sheet and a size of the sheet, and a controller changes an image forming interval in accordance with at least one of the temperature of the fixing members, the material of the sheet and the size of the sheet detected by the detecting device.

Abstract: An image forming apparatus includes: a first image bearer for bearing a toner image formed by a toner image forming device; a second image bearer for bearing the toner image which is transferred from the first image bearer; a first transferring device for transferring the toner image borne on the first image bearer onto the second image bearer or a front side of a transfer material; a second transferring device for transferring the toner image borne on the second image bearer onto a back side of the transfer material; a fixing device for fixing toner images transferred on both sides of the transfer material which is conveyed on the second image bearer and separated therefrom; and a separating claw for separating the transfer material from the second image bearer.

Abstract: The present invention relates to an image forming apparatus which forms images on both surfaces of a sheet-shaped medium using the electrophotographic method. There is described a double-sided image forming apparatus, which includes a first and a second image bearing elements to bear toner images, a first and a second transfer units for transferring the toner images to the sheet-shaped medium from the first and the second image bearing elements, a fixing unit for fixing the toner images transferred to the sheet-shaped medium, a discharger to discharge electric charges residing on the sheet-shaped medium, a detector to detect thickness and/or stiffness data of the sheet-shaped medium, and a controller to control a first image forming mode which enables to form images on both surfaces of the sheet-shaped medium, and to control a second image forming mode which enables to form an image on only a single surface of the sheet-shaped medium.

Abstract: An apparatus for forming a toner image on a sheet, comprises first and second process units each comprising a photoreceptor, a charging device, an imagewise exposing device, and a developing device. The first process unit forms a first toner image on its photoreceptor and the second process unit forms a second toner image on its photoreceptor. A rotatable intermediate transfer member has a toner image receiving surface, and the first and second process units are located in close proximity to the toner image receiving surface of the rotatable intermediate transfer member. A second transfer device transfers the second toner image from the second process unit to the toner image receiving surface. A sheet feeder feeds the sheet to the toner image receiving surface so that the second side of the sheet is provided with the second toner image; and a first transfer device transfers the first toner image from the first process unit to the first side of the sheet on the toner image receiving surface.