The invention relates to a process cartridge removably fitted in an image forming apparatus, like a laser printer and a copier, a photosensitive drum unit fitted in the process cartridge, an end member attached to a photosensitive drum of the photosensitive drum unit, a bearing member that makes up of the end member, and a method for manufacturing the bearing member.
In relation to an image forming apparatus, like a laser printer and a copier, a main body of the image forming apparatus (hereinafter often mentioned as a “main body”) is removably outfitted with a process cartridge.
The process cartridge is a member that forms details to be represented, such as letters and graphics, and transfers the details onto a recording medium, like paper. More specifically, the process cartridge is outfitted with a photosensitive drum, and details to be transferred are formed on the photosensitive drum. The process cartridge is additionally provided with other various means for forming details to be transferred on the photosensitive drum. For instance, developing means, electrifying means, and cleaning means can be mentioned as such means.
Modes of attachment and detachment of the process cartridge are as follows: namely, attaching and detaching an identical process cartridge to and from the main body for maintenance, detaching a consumed process cartridge from the main body for an exchange of it with a new one, and attaching a new process cartridge to the main body. It is feasible for a user of the image forming apparatus to perform such attachment and detachment of the process cartridge for himself or herself, and, from this viewpoint, easiest possible detachment and attachment of the process cartridge is desirable.
The photosensitive drum outfitted in the process cartridge is configured such that a drive shaft of the main body engages with the photosensitive drum directly or by way of another member, whereupon the photosensitive drum rotates upon undergoing torque from the drive shaft. Accordingly, in order to attach or detach the process cartridge to or from the main body, the photosensitive drum needs to be disengaged (detached) from or re-engaged (attached) with the drive shaft of the main body each time.
Now, if the photosensitive drum (the process cartridge) can be attached or detached by means of a shift along an axial direction of the drive shaft of the main body, making up the apparatus to this end will be comparatively easy. However, from the view point of miniaturization of the image forming apparatus and assuring space for attachment and detachment of the process cartridge, it is preferable that the process cartridge should be detached from the main body so as to be pulled out in another direction differing from the axial direction of the drive shaft and that the process cartridge is attached to the main body so as to be pushed in the direction.
Patent Document 1 discloses a configuration for enabling attachment and detachment of the process cartridge in another direction differing from the axial direction of the drive shaft of the main body. Specifically, a coupling member described in connection with Patent Document 1 is provided with a spherical portion, which enables the coupling member to be attached to a drum flange (a bearing member) in a swayable fashion. Accordingly, a part (a torque receiving member) that is attached to the coupling member to engage with the drive shaft of the main body can change its angle with respect to an axis line of the photosensitive drum by swaying around the spherical portion, thereby facilitating attachment and detachment of the photosensitive drum to and from the drive shaft of the main body.
Moreover, a structure described in connection with Non-Patent Document 1 includes a groove that is intended for introducing a torque transmission pin attached to a shaft member into a bearing member and that is formed in an interior periphery of the bearing member in a direction of rotation and facilitates attachment of the torque transmission pin to the bearing member. The document also describes a technique for forming such a bearing member in an integrated fashion.    [Patent Document 1] JP-A-2010-26473