| 摘要 |
PURPOSE:To offer a service life measuring instrument for the process cartridge which is reusable by constituting a display part which rotates according to the frequency of image formation of the process cartridge. CONSTITUTION:The service measuring instrument 20 counts the frequency of image formation of the process cartridge 3 and is constituted by supporting large- and small-diameter ratchet wheels 21 and 22 rotatably, and a disk 23 which constitutes the service life display part is bounded to the large-diameter ratchet wheel 21 by using a magic tape 31. The disk 23 rotates as the rotating speed of a photosensitive drum 1 increases and a color zone 24 which is formed thereupon and indicates service life also rotates. Then when the color zone 24 appears in a circular opening part 30 formed on the cover 29 of the process cartridge 3, a user judges that the service life of the process cartridge 3 comes to the end, and takes the process cartridge 3 out of a device main body 2 for replacement with new one. At this time, the disk 23 is peeled off the ratchet wheel 21, the color zone 24 is put back to its original position before use, and the disk 23 is bound again to the ratchet wheel 21 by using the magnetic tape 31, so that the service life measuring instrument 20 can be incorporated in the new process cartridge 3 and used again from the beginning. |
