Device for detecting the life of an image forming process unit, opening of a seal of the unit and attachment of the unit to an image forming apparatus
US4873549A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 29, 1988 |
| Grant date | Oct 10, 1989 |
| Priority date | — |
| Expiry date | Feb 29, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2221/1892
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A device for detecting the life of a process unit which is detachably mounted in an image forming apparatus includes a sensor for detecting the density of the toner in the developing device and a signal detector receiving an output from the sensor and operable to determine whether the output exceeds or is less than a predetermined value during a predetermined time period which starts after a developing roller of the process unit starts rotating. A control is connected to the signal detector and is operable to effect different operating conditions depending on whether the output exceeds or is below the predetermined value, one of the operating conditions being an indication that the life of the process unit has expired and another of the operating conditions being an indication that the life of the process unit is unexpired.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.