Abstract: An image forming apparatus for forming a toner image on a recording material, the apparatus includes a cylindrical film; a plate-like nip forming member contacted with an inner surface of the film, the nip forming member including a base member and a coating layer on the base member, the coating layer having a thermal expansion coefficient smaller than that of the base member; and a roller cooperative with the nip forming member to form a nip, wherein the coating layer is provided on a first surface of the nip forming member which is opposed to the film and on a second surface opposite from the first surface except for an outer edge portion of the nip forming member.

Abstract: A fixing apparatus for fixing a toner image to a recording material includes a cylindrical film, a heater configured to make contact with the film, the heater including a substrate and a heat generation resistor formed on the substrate, and a heat conduction member configured to make contact with a surface of the heater opposite to a surface thereof being in contact with the film, the heat conduction member having a higher thermal conductivity than that of the substrate, and being divided into parts in a generatrix direction of the film. The toner image formed on the recording material is fixed on the recording material by using heat of the film, and one of the parts of the heat conduction member is configured to make contact with the heater continuously from a center to an end of a heat generation region of the heater in the generatrix direction.

Abstract: A fixing device includes a cylindrical film, a planar heater, a heat conduction member, a supporting member, a limiting member for limiting heater end portions with respect to a generatrix direction of the film so as to prevent the end portions from moving in a heater thickness direction relative to the supporting member, and a pressing member. A fixing device state is switchable between a first state in which a press-contact force in the nip is enough to fix the toner image and a second state in which the press-contact force in the nip is smaller than the press-contact force in the first state. A surface where the supporting member opposes the heat conduction member has a shape such that with respect to the generatrix direction, a central portion of the film is projected toward the pressing member to a greater extent than an end portion of the film.

Abstract: In a fixing device according to an exemplary embodiment of the present invention, a projection portion projected in a direction opposite to a direction biased by the biasing member, from a body part of the biasing member, is provided in a biasing member configured to push a thermosensitive member which receives heat from a heater, toward the heater, so that a crack in the heater at the time of an abnormal temperature rise is prevented.

Abstract: The image heating apparatus includes a tubular shaped film; a backup member configured to be brought into contact with an outer surface of the film; a heater having an elongated shape and being configured to be brought into contact with the film, the heater including a substrate and a heat generating resistor formed; a first heat conductive member having a higher thermal conductivity than the substrate and being configured to be brought into contact with a surface of the heater, the first heat conductive member including divided first heat conductive members arranged with a gap formed therebetween; a pinching member configured to pinch the first heat conductive member; and a second heat conductive member provided in a region of the gap so as to be brought into contact with both of the heater and the pinching member.

Abstract: A fixing apparatus includes a roller, a heating rotation member configured to form a pressure portion by coming into contact with the roller, the heating rotation member being rotated by rotation of the roller, and a pressing rotation member configured to form a nip portion by coming into contact with the roller, the pressing rotation member being rotated by the rotation of the roller, wherein micro-hardness of a surface of the heating rotation member at the pressure portion and micro-hardness of a surface of the pressing rotation member at the nip portion are both higher than micro-hardness of a surface of the roller, and wherein frictional force acting on the roller at the pressure portion is larger than frictional force acting on the roller at the nip portion.

Abstract: A fixing device includes a cylindrical film, a planar heater, a heat conduction member, a supporting member, a limiting member for limiting heater end portions with respect to a generatrix direction of the film so as to prevent the end portions from moving in a heater thickness direction relative to the supporting member, and a pressing member. A fixing device state is switchable between a first state in which a press-contact force in the nip is enough to fix the toner image and a second state in which the press-contact force in the nip is smaller than the press-contact force in the first state. A surface where the supporting member opposes the heat conduction member has a shape such that with respect to the generatrix direction, a central portion of the film is projected toward the pressing member to a greater extent than an end portion of the film.

Abstract: An image forming apparatus for forming a toner image on a recording material, the apparatus includes a cylindrical film; a plate-like nip forming member contacted with an inner surface of the film, the nip forming member including a base member and a coating layer on the base member, the coating layer having a thermal expansion coefficient smaller than that of the base member; and a roller cooperative with the nip forming member to form a nip, wherein the coating layer is provided on a first surface of the nip forming member which is opposed to the film and on a second surface opposite from the first surface except for an outer edge portion of the nip forming member.

Abstract: A fixing apparatus for fixing a toner image to a recording material includes a cylindrical film, a heater configured to make contact with the film, the heater including a substrate and a heat generation resistor formed on the substrate, and a heat conduction member configured to make contact with a surface of the heater opposite to a surface thereof being in contact with the film, the heat conduction member having a higher thermal conductivity than that of the substrate, and being divided into parts in a generatrix direction of the film. The toner image formed on the recording material is fixed on the recording material by using heat of the film, and one of the parts of the heat conduction member is configured to make contact with the heater continuously from a center to an end of a heat generation region of the heater in the generatrix direction.

Abstract: A fixing device for fixing a toner image on a recording material includes: a cylindrical film; a plate-like heater contacting an inner surface of the film; a roller for forming a nip in cooperation with the heater through the film; and a thermo-sensitive member for detecting the temperature of the heater to interrupt electric power supply to the heater when the temperature of the heater reaches an abnormal temperature. The heater has a heat generating pattern symmetric with respect to a center line thereof extending in a direction perpendicular to a recording material feeding direction. The thermo-sensitive member is provided in a side which is opposite from a surface of the heater contacting the inner surface of the film and which is downstream of the center line of the heater with respect to the recording material feeding direction.

Abstract: In a fixing device according to an exemplary embodiment of the present invention, a projection portion projected in a direction opposite to a direction biased by the biasing member, from a body part of the biasing member, is provided in a biasing member configured to push a thermosensitive member which receives heat from a heater, toward the heater, so that a crack in the heater at the time of an abnormal temperature rise is prevented.

Abstract: An image forming apparatus includes an image forming portion for forming the toner image on the recording material; and a fixing portion for fixing the toner image on the recording material by feeding and heating the recording material on which the toner image is formed at a nip. The fixing portion includes a first rotatable member, a second rotatable member for forming the nip in contact with the first rotatable member, and a casing. An outer surface of the first rotatable member has electroconductivity. The casing has an opposing surface which opposes the outer surface of the first rotatable member and which has electroconductivity. In a region above a lowest point of the outer surface of the first rotatable member with respect to a direction of gravity, an insulating member is provided between the opposing surface and the outer surface of the first rotatable member.

Abstract: The image heating apparatus includes a tubular shaped film; a backup member configured to be brought into contact with an outer surface of the film; a heater having an elongated shape and being configured to be brought into contact with the film, the heater: including a substrate and a heat generating resistor formed; a first heat conductive member having a higher thermal conductivity than the substrate and being configured to be brought into contact with a surface of the heater, the first heat conductive member including divided first heat conductive members arranged with a gap formed therebetween; a pinching member configured to pinch the first heat conductive member; and a second heat conductive member provided in a region of the gap so as to be brought into contact with both of the heater and the pinching member.

Abstract: A fixing device includes a tubular film; a heater including a first surface being in contact with the film, the heater including a substrate and a heat-generating resistor; a heat-conductive member being in contact with a second surface of the heater opposite to the first surface, the heat-conductive member having a higher thermal conductivity than the substrate; and a supporting member supporting the heater with the heat-conductive member interposed therebetween. The heat-conductive member includes first and second parts at upstream and downstream ends, respectively, in a conveyance direction, and a third part between the first and second parts. The first to third parts are each held between the supporting member and the heater. A non-contact area between the heat-conductive member and the supporting member is provided between the first part and the second part in the conveyance direction. The heat-conductive member is shorter than the heater in the conveyance direction.

Abstract: A fixing apparatus for fixing a toner image to a recording material includes a cylindrical film, a heater configured to make contact with the film, the heater including a substrate and a heat generation resistor formed on the substrate, and a heat conduction member configured to make contact with a surface of the heater opposite to a surface thereof being in contact with the film, the heat conduction member having a higher thermal conductivity than that of the substrate, and being divided into parts in a generatrix direction of the film. The toner image formed on the recording material is fixed on the recording material by using heat of the film, and one of the parts of the heat conduction member is configured to make contact with the heater continuously from a center to an end of a heat generation region of the heater in the generatrix direction.

Abstract: A fixing device includes a cylindrical film, a planar heater, a heat conduction member, a supporting member, a limiting member for limiting heater end portions with respect to a generatrix direction of the film so as to prevent the end portions from moving in a heater thickness direction relative to the supporting member, and a pressing member. A fixing device state is switchable between a first state in which a press-contact force in the nip is enough to fix the toner image and a second state in which the press-contact force in the nip is smaller than the press-contact force in the first state. A surface where the supporting member opposes the heat conduction member has a shape such that with respect to the generatrix direction, a central portion of the film is projected toward the pressing member than an end portion of the film.

Abstract: A fixing device for fixing a toner image on a recording material includes a cylindrical film; a plate-like heater contacting an inner surface of the film; a roller for forming a nip in cooperation with the heater through the film; and a thermo-sensitive member for detecting a temperature of the heater to interrupt electric power supply to said heater when the temperature of said heater reaches an abnormal temperature. The heater has a heat generating pattern symmetric with respect to a center line thereof extending in a direction perpendicular to a recording material feeding direction. The thermo-sensitive member is provided in a side which is opposite from a surface of the heater contacting the inner surface of the film and which is downstream of the center line of the heater with respect to the recording material feeding direction.

Abstract: A fixing device for fixing a toner image formed on a sheet includes a cylindrical film; a heater having a first surface contacting an inner surface of the film; an opposed member forming a press-contact portion with the film therebetween; a supporting member for supporting a second surface of the heater opposite the first surface; and a heat conduction member contacting the second surface. In a generatrix direction of the film, an end portion of a contact region between the heat conduction member and the second surface is at or inside an end portion of the press-contact portion. In a region from an end portion of the contact region to an outside of an end portion of the press-contact portion with respect to the direction, the supporting member includes a first region not contacting the second surface and a second region contacting the second surface outside the first region.

Abstract: A fixing device includes a cylindrical film, a planar heater, a heat conduction member, a supporting member, a limiting member for limiting heater end portions with respect to a generatrix direction of the film so as to prevent the end portions from moving in a heater thickness direction relative to the supporting member, and a pressing member. A fixing device state is switchable between a first state in which a press-contact force in the nip is enough to fix the toner image and a second state in which the press-contact force in the nip is smaller than the press-contact force in the first state. A surface where the supporting member opposes the heat conduction member has a shape such that with respect to the generatrix direction, a central portion of the film is projected toward the pressing member to a greater extent than an end portion of the film.

Abstract: An image heating apparatus for heating a toner image formed on a recording material, the image heating apparatus includes a heater including a substrate and a heat generating resistor thereon for generating heat for heating the toner image, by electric power supply; an electric power shut-off member operable in response to an abnormality temperature rise of the heater to shut off the electric power supply; and a heat conduction member having a thermal conductivity, in a direction of a thickness of the substrate, higher than that of the substrate, wherein a contact area between the heat conduction member and the substrate is larger than a contact area between the heat conduction member and the electric power shut-off member.