Method of sensing a remaining amount of developer for a color image forming apparatus
US4987449A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 4, 1989 |
| Grant date | Jan 22, 1991 |
| Priority date | — |
| Expiry date | Dec 4, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/5041
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A remaining developer sensing method for an image forming apparatus operable with a plurality of replaceable developing units each storing a developer of different color maintains the amounts of developers of remaining in the individual developing units equal to each other at all times. An exclusive sensor responsive to the remaining amount of toner is mounted on the bottom of a toner hopper of each developing unit and outputs a toner absence signal when the amount of toner remaining in the associated developing unit becomes short. When the toner absence signal continuously appears over a predetermined period time, the operation of the apparatus is inhibited. The predetermined period time differs from one developing unit to another.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.