Abstract: A fixing device includes: a cylindrical film; a nip forming member; and a back-up member for forming a nip. The nip forming member includes a projected portion. The projection amount of the projected portion is smaller in an end portion region positioned at an end portion of the projected portion with respect to a generatrix direction of the film than in a central region positioned at a central portion of the projected portion with respect to the generatrix direction, at least a part of the end portion region being inside a feeding region of a maximum-sized recording material usable in the fixing device. With respect to the recording material feeding direction, the width of the part of the projected portion inside the nip is broader in the end portion region than in the central region.

Abstract: A fixing apparatus fixes a toner image on a recording material by conveying and heating the recording material at a nip portion, and includes a first rotating member, a second rotating member configured to form the nip portion with the first rotating member, the first and second rotating members being arranged such that rotation of the second rotating member causes rotation of the first rotating member, a frame configured to support the second rotating member, so as to be rotatable and an opening and closing part arranged to open and close relative to the frame on the downstream side of the nip portion in the conveyance direction of the recoding material, the opening and closing part having a duct through which air flows.

Abstract: An image forming apparatus for forming a toner image on a recording material has an image forming unit configured to form the toner image on the recording material; a fixing unit configured to fix the toner image on the recording material while heating and conveying the recording material bearing the toner image at a nip portion, the fixing unit including a heating rotation member and a roller forming the nip portion with the heating rotation member; and a voltage applying unit configured to apply a potential difference between a surface of the heating rotation member and a surface of the roller, wherein a plurality of print modes different in conveyance speed of the recording material at the nip portion are carried out, and wherein the voltage applying unit applies the potential difference smaller in a first print mode than the potential difference in a second print mode.

Abstract: A fixing device includes first and second members, a frame supporting the second member, and two pressure mechanisms provided on either end of the first member. The mechanism includes a lever having one end supported by the frame in a rotatable manner in a pressure direction, and a helical compression spring disposed between a first spring support provided on the other end of the lever and a second spring support on the frame. At least one of the first and second spring supports includes a first area and a second area closer to the spring in the axial direction than the first area, the first area is in contact with an area of the spring close to a winding end of the spring, and the second area is in contact with an area of the spring farther away from the winding end in a winding direction than the first area.

Abstract: A fixing device includes: a cylindrical film; a nip forming member; and a back-up member for forming a nip. The nip forming member includes a projected portion. A projection amount of the projected portion is smaller in an end portion region positioned at an end portion of the projected portion with respect to a generatrix direction of the film than in a central region positioned at a central portion of the projected portion with respect to the generatrix direction, at least a part of the end portion region being inside a feeding region of a maximum-sized recording material usable in the fixing device. With respect to the recording material feeding direction, a width of the part, of the projected portion, inside the nip is broader in the end portion region than in the central region.

Abstract: A fixing device includes: a cylindrical film; a nip forming member; and a back-up member for forming a nip. The nip forming member includes a projected portion. The projection amount of the projected portion is smaller in an end portion region positioned at an end portion of the projected portion with respect to a generatrix direction of the film than in a central region positioned at a central portion of the projected portion with respect to the generatrix direction, at least a part of the end portion region being inside a feeding region of a maximum-sized recording material usable in the fixing device. With respect to the recording material feeding direction, the width of the part of the projected portion inside the nip is broader in the end portion region than in the central region.

Abstract: A developing device configured to develop a latent image formed on an image bearing member includes a rotatable developing-agent bearing member configured to bear developing agent, a developing container configured to form a developing-agent storage chamber that stores the developing agent, a developing-agent regulating portion provided in the developing container to regulate an amount of the developing agent born on the developing-agent bearing member, a support portion configured to support the developing-agent bearing member movably relative to the developing-agent regulating portion, and a pressurizing member configured to pressurize the developing-agent bearing member toward the developing-agent regulating portion. A contact portion of the developing-agent regulating portion with the developing-agent bearing member is fixed to the developing container without forming a gap from the developing container on a downstream side in a pressurizing direction of the pressurizing member.

Abstract: The fixing apparatus includes a sleeve, a nip portion forming member that contacts an inner surface of the sleeve, a pressure member, and a regulation member for regulating movement of the sleeve. The regulation member includes a first surface and a second surface. The first surface on an upstream side of the nip portion in a conveyance direction of the recording material includes a region in which the distance between the inner surface of the sleeve and the first surface in a radial direction of the sleeve increases toward a center portion of the sleeve in the generatrix direction, and in which the end surface of the sleeve contacts the region when the sleeve moves in the generatrix direction.

Abstract: A fixing device includes: a cylindrical film; a nip forming member; and a back-up member for forming a nip. The nip forming member includes a projected portion. A projection amount of the projected portion is smaller in an end portion region positioned at an end portion of the projected portion with respect to a generatrix direction of the film than in a central region positioned at a central portion of the projected portion with respect to the generatrix direction, at least a part of the end portion region being inside a feeding region of a maximum-sized recording material usable in the fixing device. With respect to the recording material feeding direction, a width of the part, of the projected portion, inside the nip is broader in the end portion region than in the central region.

Abstract: A developing device configured to develop a latent image formed on an image bearing member includes a rotatable developing-agent bearing member configured to bear developing agent, a developing container configured to form a developing-agent storage chamber that stores the developing agent, a developing-agent regulating portion provided in the developing container to regulate an amount of the developing agent born on the developing-agent bearing member, a support portion configured to support the developing-agent bearing member movably relative to the developing-agent regulating portion, and a pressurizing member configured to pressurize the developing-agent bearing member toward the developing-agent regulating portion. A contact portion of the developing-agent regulating portion with the developing-agent bearing member is fixed to the developing container without forming a gap from the developing container on a downstream side in a pressurizing direction of the pressurizing member.

Abstract: Provided is a technology that enhances the detection precision of the residual amount of a developer. An apparatus according to the invention includes: an accommodating portion in which a developer is accommodated; a sheet-like stirring member that, by rotating, stirs the developer accommodated in the accommodating portion; a piezoelectric element that is affixed to the stirring member and that outputs voltage when being deformed; and a deflection forming portion that comes in contact with the stirring member, thereby causing the stirring member to deflect, when a free end of the rotating stirring member is outside a developer accumulation region in the accommodating portion.

Abstract: A developing device configured to develop a latent image formed on an image bearing member includes a rotatable developing-agent bearing member configured to bear developing agent, a developing container configured to form a developing-agent storage chamber that stores the developing agent, a developing-agent regulating portion provided in the developing container to regulate an amount of the developing agent born on the developing-agent bearing member, a support portion configured to support the developing-agent bearing member movably relative to the developing-agent regulating portion, and a pressurizing member configured to pressurize the developing-agent bearing member toward the developing-agent regulating portion. A contact portion of the developing-agent regulating portion with the developing-agent bearing member is fixed to the developing container without forming a gap from the developing container on a downstream side in a pressurizing direction of the pressurizing member.

Abstract: A developer container unit includes a container containing developer and a piezoelectric film for detecting an amount of developer in the container. A sensitivity of the piezoelectric film to a stress in a direction parallel to a film surface is greater than a sensitivity of the piezoelectric film to a stress in a direction perpendicular to the film surface, and the piezoelectric film is deformable with a movement thereof relative to the developer.

Abstract: The fixing apparatus includes a sleeve, a nip portion forming member that contacts an inner surface of the sleeve, a pressure member, and a regulation member for regulating movement of the sleeve, in which the regulation member includes a first surface and a second surface, in which the first surface on an upstream side of the nip portion in a conveyance direction of the recording material includes a region in which a distance between the inner surface of the sleeve and the first surface in a radial direction of the sleeve increases toward a center portion of the sleeve in the generatrix direction, and in which the end surface of the sleeve contacts the region when the sleeve moves in the generatrix direction.

Abstract: An oxide single crystal having a composition represented by RExSi6O1.5x+12 (RE: La, Ce, Pr, Nd, or Sm, x: 8 to 10) is grown by using the Czochralski method such that the crystal growth orientation coincides with the c-axis direction. The solidification rate (the weight of the grown crystal÷the weight of the charged raw material) in the crystal growth is less than 45%.

Abstract: An oxide single crystal having a composition represented by RExSi6O1.5x+12 (RE: La, Ce, Pr, Nd, or Sm, x: 8 to 10) is grown by using the Czochralski method such that the crystal growth orientation coincides with the c-axis direction. The solidification rate (the weight of the grown crystal÷the weight of the charged raw material) in the crystal growth is less than 45%.

Abstract: When a fixing device becomes uncontrollable and a large amount of electric power is continuously supplied to the heater, concentration of mechanical stress on a heater is suppressed, whereby shear fracture of the heater is prevented from occurring. A longitudinal region of the heater in which a heat generation resistive member is provided is supported by a heater support surface of a heater holder, and an opposed surface of the heater holder that is opposed to a longitudinal region of the heater in which the heat generation resistive member is not provided is designed not to be in contact with the heater.

Abstract: The invention prevents cracking of heater that may occur when a fixing device becomes uncontrollable and provides an image forming apparatus that is advantageous from the viewpoint of recycling of parts. A heater support member that supports a heater during abnormal temperature rise is provided at a position at which a heater holder deforms greatly when abnormal temperature rise of the heater occurs.

Abstract: The invention prevents cracking of heater that may occur when a fixing device becomes uncontrollable and provides an image forming apparatus that is advantageous from the viewpoint of recycling of parts. A heater support member that supports a heater during abnormal temperature rise is provided at a position at which a heater holder deforms greatly when abnormal temperature rise of the heater occurs.

Abstract: When a fixing device becomes uncontrollable and a large amount of electric power is continuously supplied to the heater, concentration of mechanical stress on a heater is suppressed, whereby shear fracture of the heater is prevented from occurring. A longitudinal region of the heater in which a heat generation resistive member is provided is supported by a heater support surface of a heater holder, and an opposed surface of the heater holder that is opposed to a longitudinal region of the heater in which the heat generation resistive member is not provided is designed not to be in contact with the heater.