Image forming apparatus

#1. Field of the Invention

#The present invention relates to an image forming apparatus which has a heat member for heating a recording material bearing an unfixed image thereon and is configured so that a longitudinal center of the heat member becomes a conveyance center (the center with respect to the direction intersecting with a conveyance direction) of the recording material, that is, relates to an image forming apparatus of an electrophotographic system or the like, for transporting (paper feeding) a recording material by setting a center of the recording material to be transported as reference.

#In addition, in this specification, even a plurality kinds of recording materials whose paper widths in a direction intersecting with the conveyance direction differ with each other, in the case of being set correctly, such a configuration that the width center of each recording material is transported at a certain position (generally, a longitudinal center position of the heat member) with respect to the direction intersecting with the conveyance direction is referred to as “a center of the paper feeding reference”, and its line is referred to as “a center line of the paper feeding reference”.

#FIG. 1 is a schematic configuration view of an example of an image forming apparatus according to Embodiment 1.

#FIG. 2 is a transversal side view of an essential portion of a fixing device according to Embodiment 1.

#FIG. 3 is a longitudinal front view of an essential portion of the fixing device according to Embodiment 1.

#FIG. 1 is a schematic configuration view of an image forming apparatus 100 according to Embodiment 1. The image forming apparatus is a laser beam printer (referred to as “printer” hereinafter) using a transfer type electrophotographic process.

#The printer 100 is electrically connected to a host device 200 such as a personal computer. The printer 100 receives a print request signal from the host device 200 and image data. The image data is expanded by a printer control part 101 as control means. Then, a drum type electrophotographic photosensitive member (referred to as “photosensitive drum” hereinafter) 1 serving as an image bearing member is driven to rotate in a clockwise direction of an arrow at a predetermined speed by predetermined control timing of image forming sequence control by the printer control part 101. Further, a laser scanner 3 which is an exposure device is driven.

#The photosensitive drum 1 is uniformly charged to be predetermined polarity and potential by a contact charging roller 2 serving as an electrostatic charging device while in its rotation process. Then, the thus-uniformly charged surface of the photosensitive drum 1 is scanned and exposed by a laser beam 3a output by being modulated in response to the above-mentioned expanded image data by the laser scanner 3, thereby forming an electrostatic latent image corresponding to the image data on the surface of the photosensitive drum 1. The electrostatic latent image is developed as a toner image by a development device 4.