Field of the Invention
The present invention relates to a developing cartridge attachable/detachable to/from a main body of an image forming apparatus, and an image forming apparatus that forms an image on a recording medium using an electrophotographic technology.
Description of the Related Art
In an image forming apparatus such as a printer using an electrophotographic technology, a photosensitive drum is first uniformly charged by a charging roller to form an image on a sheet such as a recording sheet. Next, the charged photosensitive drum is selectively exposed by an exposing apparatus to form an electrostatic latent image on the photosensitive drum. Further, the electrostatic latent image formed on the photosensitive drum is developed by a developing apparatus to form a toner image on the photosensitive drum. The toner image formed on the photosensitive drum is transferred onto a sheet. After that, the toner image transferred onto the sheet is heated and pressed to be fixed onto the sheet. Thus, an image is formed on the sheet. In addition, residual toner on the photosensitive drum after the toner image has been transferred onto the sheet is removed by a cleaning blade.
In such an image forming apparatus, it is generally necessary to perform the maintenance of processing means such as a photosensitive drum and a developing apparatus. Therefore, in recent years, a photosensitive drum, a charging roller, a developing apparatus, a cleaning blade, etc., are often integrated as a cartridge in order to facilitate the maintenance of processing means. Such a cartridge is called a process cartridge and attachable/detachable to/from a main body of an image forming apparatus. By employing such a process cartridge system, a user is allowed to facilitate the maintenance of processing means to form an image on a sheet. Here, a process cartridge has generally a drum unit provided with a photosensitive drum and a developing unit provided with a developing apparatus.
Here, in a technology disclosed in Japanese Patent Application Laid-open No. 2011-039564, a developing unit is attachable/detachable to/from a main body of an image forming apparatus as a developing cartridge. In addition, in the technology disclosed in Japanese Patent Application Laid-open No. 2011-039564, the main body of the image forming apparatus is provided with an opening/closing door, and exposed to an outside when the opening/closing door is opened. Further, the developing cartridge may be attached to the main body of the apparatus in a state in which the opening/closing door is opened. Here, in the technology disclosed in Japanese Patent Application Laid-open No. 2011-039564, the opening/closing door is provided with a spring member. Further, when the opening/closing door is closed in a state in which the developing cartridge is attached to the main body of the apparatus, the spring member provided on the opening/closing door presses the developing cartridge. Therefore, when the developing cartridge is pressed toward the photosensitive drum, a developing roller provided in the developing cartridge is pressed onto the photosensitive drum. Thus, the developing roller is positioned with respect to the main body of the image forming apparatus.