Toner density control device for an image forming apparatus
US5057870A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 31, 1990 |
| Grant date | Oct 15, 1991 |
| Priority date | — |
| Expiry date | Jan 31, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S222/01
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A toner density control device for an electrophotographic copier, facsimile apparatus, laser printer or similar image forming apparatus of the type forming an image by depositing a toner on an electrostatic latent image. The device has two sensing circuits, i.e., a toner density sensing circuit and an image density sensing circuit. When one of the two sensing circuits fails, a toner is supplemented in response to an output of the other or normal sensing circuit. When the failed sensing circuit is restored to normal, the toner supply responsive solely to the other sensing circuit is cancelled so that both of the two sensors join in the toner supply control. When both the toner density sensors and the image density sensing means fail, the image forming apparatus is automatically disabled with the failure being displayed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.