Apparatus for controlling toner density in a developing device of an electrophotographic or electrostatic image forming apparatus
US5216469A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 14, 1991 |
| Grant date | Jun 1, 1993 |
| Priority date | — |
| Expiry date | May 14, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/0897
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A developing device in an image forming apparatus has a developing sleeve through which a two-component toner material is applied onto a photosensitive surface. The developing device has an optical sensor assembly including a sensor casing opening towards the developing sleeve and closed by a transparent electroconductive windowpane to which one of two bias voltages is selectively applied for depositing or clearing toner on and off from the windowpane. The sensor assembly also includes an infrared light source for radiating infrared rays of light through the windowpane and a light receiving element for providing an output indicative of the density of toner deposited on the windowpane while the windowpane is electrically connected with the bias voltage source. A central processing unit operates in response to the output from the light receiving element to calculate the density of toner contained in the developing material. Any change in density of the toner in the developing material can be compensated for.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.