| 摘要 |
PURPOSE:To carry out the service life management of a photosensitive body without hindrance by providing a nonvolatile storage element and a comparing means and maintaining reliability on printing number data. CONSTITUTION:The nonvolatile storage element 23 is provided with printing number storing addresses A, B and C, and printing numbers are stored as counted value data A, B and C. When power is turned on, the data is read out from the processor 21 and compared with each other. When A coincides with B, A is validated and stored in an erasing type element 24, whereas if Anot equal to B, B is compared with C. If B coincides with C, B is stored in the element 24, whereas if Cnot equal to B, C is compared with A. If C coincides with A, C is stored in the element 24, whereas if Cnot equal to A, the max. value of A - C is approximated mostly to the service life counted value of a photosensitive drum 2 and stored in the element 24. On the completion of writing the data to the element 24, printing is waited for. When the printing is started, +1 is applied to the contents of the erasing type element 24 at every printing, and updated printing numbers are stored in the address A - C of the usual storage element. With this constitution, reliability on the printing number is secured and the service life management of the photosensitive body can be carried out without hindrance. |
