Image density control method for an image forming apparatus
US5258248A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1992 |
| Grant date | Nov 2, 1993 |
| Priority date | — |
| Expiry date | Apr 7, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/00042
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An image density control method for an image forming apparatus of the type forming a latent image of a document image on a photoconductive element and developing the latent image by a toner to produce a toner image by an electrophotographic procedure. A background pattern whose density is substantially the same as the background density of a document, i.e., a light pattern is illuminated to electrostatically form a latent image thereof on the photoconductive element. The latent image is developed by the toner, and the density of the resultant toner image is optically sensed by an image density sensor. A change in background density due to contamination or an increase in background potential, for example, is detected. Based on the detected change in background density, a quantity of light for imagewise exposure or similar factor dictating the developing ability is corrected, i.e., it is controlled to the light side if the density has been shifted to the dark side. The detection of the background density and the control for correction are effected only when the charge retaining ability of the photoconductive element is stable.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.