JP2004012682A5 - - Google Patents

Claims (21)

At least a heating roll whose surface is heated and rotating, an endless pressure belt which is in contact with and driven by the surface of the heating roll, and urges the pressure belt from the circumference to the surface of the heating roll. A pressing member that forms a nip portion through which a recording sheet for holding an unfixed toner image can be inserted between the heating roll and the pressure belt,
A support frame extending in the width direction of the pressure belt; an elastic member disposed in a protruding state from the support frame toward the pressure belt; and urging the pressure belt with a surface; A fixing device comprising: a hard and flexible low friction sheet disposed on an urging surface of an elastic member, the surface of which is in contact with the pressure belt. The low friction sheet, said has elastic members and physically independent, that the surface in contact with the said pressure belt has a substantially follow curved planar of the heating roll autonomously The fixing device according to claim 1.   The fixing device according to claim 2, wherein the low friction sheet has a cap shape that can be fitted over the elastic member.   4. The fixing according to claim 2, wherein a deflection amount of the low friction sheet in a width direction of the pressure belt is greater than or equal to a deflection amount of the heating roll in a temperature condition during operation of the fixing device. apparatus.   The fixing device according to claim 1, wherein the low friction sheet is made of a resin.   The fixing device according to claim 1, wherein a thickness of the low friction sheet is 2.0 mm or less.   The fixing device according to claim 1, wherein the elastic member is physically independent of the support frame.   8. The fixing device according to claim 7, wherein in a portion where the support frame and the elastic member are in contact with each other, the surface shapes at the time of no load are different from each other.   The fixing device according to claim 8, wherein a cross-sectional shape perpendicular to the longitudinal direction of the elastic member when not loaded is a substantially rectangular shape.   The fixing device according to claim 1, wherein the elastic member is made of a rubber material.   The fixing device according to claim 1, wherein a surface shape of a portion of the support frame that contacts the elastic member is a curved surface shape that substantially follows the surface shape of the heating roll.   12. The fixing device according to claim 1, wherein in the nip pressure distribution of the nip portion, the nip pressure near the outlet is larger than the vicinity of the inlet of the nip portion.   13. The fixing device according to claim 12, wherein in the cross-sectional shape perpendicular to the longitudinal direction of the elastic member when no load is applied, the thickness near the exit is greater than the vicinity near the entrance of the nip portion.   The fixing device according to claim 12, wherein a material of the elastic member is higher in hardness in the vicinity of the exit than in the vicinity of the entrance of the nip portion.   The fixing according to claim 12, wherein a surface shape of a portion of the support frame that contacts the elastic member protrudes in the vicinity of the exit of the nip portion, rather than a surface shape that follows the surface shape of the heating roll. apparatus.   16. The nip pressure distribution at the nip portion in a state where the heating roll is not bent has a large nip pressure at the center in the width direction of the pressure belt. Fixing device.   The fixing device according to claim 16, wherein a central portion protrudes in a cross-sectional shape in a longitudinal direction of the elastic member when no load is applied.   The fixing device according to claim 16, wherein a planar shape of a portion of the support frame that is in contact with the elastic member protrudes at a central portion in a longitudinal direction.   The fixing device according to claim 16, wherein a shim having a predetermined thickness is sandwiched between the support frame and the elastic member at a central portion in a longitudinal direction. The fixing device according to claim 1, wherein an average surface pressure of the nip pressure in the nip portion is 5.0 × 10 ⁵ Pa or less. At least an unfixed toner image forming device that forms an unfixed toner image on the surface of the recording sheet by electrophotography, and a fixing device that fixes the unfixed toner image held on the surface of the recording sheet by heating and pressing; An electrophotographic apparatus comprising:
An electrophotographic apparatus, wherein the fixing device is the fixing device according to claim 1.