Patent ID: 8204421
Filing Date: 2012-06-19
Classification: G03G

Abstract:
1. A fusing apparatus for fusing a toner image transferred onto a recording medium using heat and pressure, comprising: a fusing roller; a heating unit configured to heat the fusing roller; an endless pressing belt disposed opposite the fusing roller; a pressing member configured to contact an internal peripheral surface of the endless pressing belt; and a biasing unit configured to apply a biasing force to the pressing member in order to press the pressing member onto the internal peripheral surface of the pressing belt so that the pressing belt can be pressed onto the fusing roller, wherein a fusing nip is formed between the fusing roller and the pressing belt when the pressing belt is pressed onto the fusing roller, wherein the recording medium with the toner image transferred thereon is passed through the fusing nip in order to fuse the toner image onto the recording medium using heat applied to the recording medium via the fusing roller, wherein the fusing roller includes a positive crown portion and a negative crown portion that are alternately formed on a surface of the fusing roller along the axial direction, wherein the pressing member includes a convex surface portion and a concave surface portion that are alternately formed on a surface of the pressing member along the longitudinal direction, wherein, when the pressing member is pressed onto the fusing roller, the positive crown portion of the fusing roller is engaged with the concave surface portion of the pressing member while the negative crown portion of the fusing roller is engaged with the convex surface portion of the pressing member, wherein the pressing force exerted by the pressing member on the fusing roller is greater at a central portion of the fusing nip than at an end portion thereof.