This invention relates to a mounting structure of a photosensitive drum capable of easily attaching a photosensitive drum on an electrostatic image forming apparatus and detaching the photosensitive drum from the same.
Conventionally, there have been provided image forming apparatus such as an electrostatic copying apparatus and a printer, in which mounting and dismounting of a photosensitive drum are performed by moving it in the radial direction.
In such an image forming apparatus, such a structure is generally employed that a photosensitive drum is supported in a condition to be driven, by connecting the end of a support shaft inserted into the photosensitive drum to a drive unit disposed in the main body of the apparatus (see Japanese Laid-open Patent Application No. 182682/1983 for example).
In the case of the above supporting structure, however, it is necessary to insert the support shaft into the photosensitive drum and draw out the support shaft from the photosensitive drum every time the photosensitive drum is mounted and dismounted. It is also necessary to engage the end of the support shaft inserted into the photosensitive drum with the drum drive unit. Therefore, the photosensitive drum cannot be detached or attached promptly.
Furthermore, when engaging the support shaft with the drum drive unit, positioning of the support shaft to fit to the drum drive unit was difficult, and it took time to engage the two. Still more, a considerable extra space was needed in the draw-out direction in order to draw out the support shaft from the drum drive unit, and a wide space was required for installation of the apparatus. This requirement for extra space was a particularly difficult problem when installing an image forming apparatus in which the overall length of the support shaft was long, for example, a large-sized image forming apparatus with the copy size of up to A0 (Japanese Industrial Standard) format.