Abstract: A fixing device includes: a heating rotary member having a heating layer generating heat upon current application; a pressurizing rotary member brought into pressure-contact with an outer circumferential surface of the heating rotary member to form fixing nip, through which a sheet on which unfixed toner image is formed passes for heat fixing; circular electrodes that are circumferentially formed at two respective positions sandwiching a sheet passing region therebetween, on the outer circumferential surface, and feed electrical power to the heating layer, the electrodes are each metallic and formed of at least two electrode layers including a first electrode layer layered directly on the heating layer and a second electrode layer as an outermost layer, linear expansion coefficient difference between the first layer and the heating layer is smaller than that between the second layer and the heating layer, and the second layer is more oxidation-resistant than the first layer.

Abstract: Provided is a fixing device that uses an induction heating method and is capable of shortening a warm-up time period by accelerating the speed of increase in the temperature of a fixing belt. The fixing device forms a fixing nip by having a pressurizing roller pressurize a fixing roller, which is positioned inside a rotation path of a fixing belt having a hollow cylindrical shape, from outside the rotation path via the fixing belt. Given that Db is an inner diameter of the fixing belt, Dr is an outer diameter of the fixing roller, and a rate X is a value obtained by dividing the inner diameter Db of the fixing belt by the outer diameter Dr of the fixing roller, the fixing belt and the fixing roller that satisfy a relationship 0<X?1.18 are used.

Abstract: A heat generating roller (19) which generates a heat when magnetic flux is applied from outside, which has high ability to control an amount of heat generation of itself and which has sufficient strength, comprising a main heating layer (31) made of a material having a low electric resistivity, a heat controlling layer (30) made of magnetic metal consisting at least nickel, a heat insulation layer (36) having a low heat conductivity, and a stiff metal core (35), in order as above from outside, wherein the heat controlling layer (30) is annealed, and the heat controlling layer (30) and the heat insulation layer (36) are bonded to each other.

Abstract: A heat generating sleeve (19) having a high ability to control an amount of heat generation of itself and sufficient strength comprises a heat controlling layer (30) consisting of annealed permalloy, and a main heating layer (31) consisting of unannealed metal plated on a surface of the heat controlling layer (30).

Abstract: The present invention provides an induction heating unit enabling to attaching coil on coil attaching surface of bobbin with a high degree of accuracy, and a fixing device capable of maintaining the distance between the coil and the member to be heated at a high degree of accuracy, ensuring uniformity of temperature distribution of the member to be heated, rising temperature at a high speed, and enhancing quality of fixation. In an induction heating unit 30 comprising a magnetizing coil 39 attached on a coil bobbin 38 which is disposed outside of annular body 19 to be heated, the unit comprising: a layer of elastic adhesive 44a provided on the outer surface of the coil bobbin 38; a magnetizing coil 39 provided on the layer of elastic adhesive 44a, the magnetizing coil 39 being wound beforehand following an attaching surface; and a layer of elastic adhesive 44b provided on the magnetizing coil 39.

Abstract: A belt-type fixing device is provided in which a nip pressure distribution in a fixing nip is made generally uniform with respect to a paper feeding direction and which thereby prevents occurrence of image noise even when a thick paper is fed. The belt-type fixing device has: an endless-sheet-like fixing belt, a pressurizing roller which has elasticity and on which a paper is passed through a fixing nip that is contact part between the pressurizing roller and an outer circumferential surface of the belt member, and a nip forming member which is provided in contact with an inner surface of the fixing belt, which relatively presses the fixing belt against the pressurizing roller, of which an opposite surface pressing the pressurizing roller is formed as a curved surface extending along an outer circumferential surface of the pressurizing roller, and of which the opposite surface is composed of an elastic layer.

Abstract: A belt-type fixing device is provided in which a wide fixing nip having a generally flat pressure distribution with respect to a paper feeding direction can be formed. The belt-type fixing device of the invention has a nip forming member that is fixed inside an endless-sheet-like fixing belt to be heated so as to be incapable of rotating, and a rotatable pressurizing roller that is in pressure contact with the nip forming member with the fixing belt interposed between. Contact part between the fixing belt and the pressurizing roller forms a fixing nip, and a surface of the nip forming member that is opposite to the pressurizing roller is configured as a curved surface extending along an outer circumferential surface of the pressurizing roller so that a pressure distribution in the fixing nip is made generally flat with respect to the paper feeding direction.

Abstract: A belt-type fixing device is provided in which a nip pressure distribution in a fixing nip is made generally uniform with respect to a paper feeding. direction and which thereby prevents occurrence of image noise even when a thick paper is fed.

Abstract: A belt-type fixing device is provided in which a wide fixing nip having a generally flat pressure distribution with respect to a paper feeding direction can be formed.

Abstract: A corona discharge device used in an electrophotographic image forming apparatus includes a discharge member such as a saw-toothed discharge member having sharp discharge ends, and a power supply which applies to the discharge member a discharge voltage containing at least an AC voltage component, wherein at least each discharge end portion of the discharge member is made of an electrically conductive material, which contains nickel and chromium, and/or is coated with a material having a high electric resistance. In the case where the saw-toothed discharge member is employed, a distance D between the discharge end and a member to be charged, and a discharge end pitch P are determined to satisfy a relationship of 2≦D/P≦8.

Abstract: A fixing apparatus for controlling an oil transfer apparatus to maintain a releasing agent holding layer such that it is not always saturated with the releasing agent. This makes it a compact, cost-effective unit with a long service life and provides a uniform, stable oil coating that eliminates image noise problems. In order to use a constant and minimum necessary amount of releasing agent, a releasing agent supply nozzle is incorporated with multiple protrusive or retrusive droplet growth assisting members at or near multiple releasing agent discharge ports. The supply nozzle used for supplying the oil has multiple discharge holes having approximately equal opening cross-sectional areas and an equalizing member which equalizes the amount of oil discharged from each discharge hole. The outer diameter D1 of the oil supply roller, the outer diameter D2 of the metal core and the distance P of adjacent through-holes formed on the periphery of the metal core satisfy a relation, 0.6<D1.multidot.(D1-D2)/(D2.

Abstract: A belt fixing system includes a rotatably supported belt, a heating member for heating the belt, a pressure member which contacts with a circumference of the belt to form a nipping region therewith where a toner image supported on a sheet member is fixed onto the sheet member. The system further includes a first detector for detecting a portion of the belt where it has touched with the sheet member at the nipping region, and a controller for controlling the heating member so that an amount of heat supply to the belt is changed in response to an detecting result of the first detector.

Abstract: A fixing device for an image forming apparatus having low heat losses. The fixing device consists of a fixing roller and a compression roller for abutting upon it under pressure. The fixing roller and compression roller have a release layer each formed on the surface of a core metal formed of an aluminum hollow cylinder. The release layer on the surface of the fixing roller is formed of a composite material of metallic powder of good thermal conductive material such as nickel, and fluorine resin such as polytetrafluoroethylene (PTFE) and polyphenylene alkoxyether (PFA), and has spectral emissivity at a wavelength of 5 to 10 .mu.m being within a range of 0.1 to 0.65. The compression roller is provided with a release layer formed of fluorine resin like the conventional one, or the same material as the release layer on the surface of the aforesaid fixing roller, having lower spectral emissivity.

Abstract: An image forming apparatus having an electrostatic latent image carrier, and a charging device which includes an electric discharge electrode having a plurality of projection and a grid electrode located between the electric discharge electrode and the surface of the electrostatic latent image carrier. A grid electrode electric current Ig passing through the grid electrode and an image carrier electric current Ip passing through the conductive base of electrostatic latent image carrier satisfy the following relationship:1.5.ltoreq.Ig/Ip.ltoreq.4.

Abstract: An image forming apparatus, including a laminate image-bearing member having a dielectric layer or photoconductive layer, superimposed on an electrically conductive substrate, a transfer member for making pressure contact with said image-bearing member, and a cleaning member for cleaning the surface of said image-bearing member through contact therewith, forms an electrostatic latent image on said image-bearing member, develops said latent image into a visible toner image, and transfers said toner image from said image-bearing member to a transfer sheet passing through a contact-pressure nip portion between said image-bearing member and a transfer member by applying a controlled constant-current regulated transfer bias voltage to said transfer member.

Abstract: A charging device with a plate-like electrode having a plurality of protrusions, the charging device having a cleaning device including cleaning members which are positioned bilaterally to the electrode and grip the electrode therebetween to clean. The cleaning device cleans the electrode while the cleaning members slide on a guide formed along the electrode, or the cleaning device cleans the electrode by griping the electrode by the cleaning members which are positioned along the electrode.

Abstract: Grid wires arranged in an axial direction of a photoconductive drum have a positional relation with projecting electrodes arranged at regular intervals in an axial direction of the photoconductive drum at a position opposite to the surface of the photoconductive drum wherein the grid wires and the projecting electrodes positioned adjacent to each other are equally arranged in distance to uniformly discharge an electric charge to the surface of the photoconductive drum from each of the projecting electrodes so that uniform charging can be accomplished in an axial direction of the photoconductive drum.