Field of the Invention
The disclosure relates to a fixing device to be used in an electrophotographic image forming apparatus, such as a copying machine, a laser beam printer, and a facsimile.
Description of the Related Art
A fixing device with a film having a low heat capacity is known as a fixing device to be disposed in an electrophotographic image forming apparatus. Such a fixing device includes a cylindrical film, a sliding plate that slides while in contact with an inner surface of the film, a heater that heats the sliding plate with radiation heat, and a roller that nips the film with the sliding plate to form a nip portion, as discussed in Japanese Patent Application Laid-Open No. 2013-114057. In the nip portion, the fixing device heats a recording medium bearing an image while conveying the recording medium to fix the image on the recording medium. Thus, this fixing device has features of a short warm-up time and low energy consumption.
Japanese Patent Application Laid-Open No. 2013-114057 discusses a sliding plate of a fixing device. The sliding plate has a curvature portion that is curved along an inner surface of a film on an upstream side of a nip portion in a recording medium conveyance direction. The curvature portion can preheat the film before the film enters the nip portion. Thus, the curvature portion has a merit that the film can be effectively heated.
However, since a longitudinal end portion of the film extending to an outer side of a longitudinal end portion of a roller is not retained in the nip portion, an inner side of the film strongly slides against the curvature portion of the sliding plate. The inner side of the film is thus liable to be abraded.