Patent ID: 11886132
Assignee: BROTHER KOGYO KABUSHIKI KAISHA
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 6:
7. A transfer belt unit for use with an image forming apparatus comprising a photosensitive drum and a cleaning roller, the cleaning roller being rotatable at one of a first rotational speed and a second rotational speed faster than the first rotational speed,
the transfer belt unit comprising:
a transfer belt configured to transfer toner on the photosensitive drum onto a sheet conveyed to a portion between the photosensitive drum and the transfer belt, the transfer belt being configured to make contact with the cleaning roller and to be cleaned by the cleaning roller; and
a belt memory configured to store therein a deterioration quantity of the transfer belt calculated on a basis of a first rotation time period and a second rotation time period, the first rotation time period indicating a total of a period of time that the cleaning roller rotates at the first rotational speed during a cleaning operation added to a previously-stored period of time that the cleaning roller rotated at the first rotational speed, the second rotation time period indicating a total of a period of time that the cleaning roller rotates at the second rotational speed during the cleaning operation added to a previously-stored period of time that the cleaning roller rotated at the second rotational speed.