Device for adjusting output of image density sensor incorporated in image forming equipment
US5245390A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 1991 |
| Grant date | Sep 14, 1993 |
| Priority date | — |
| Expiry date | Dec 20, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/00042
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A device incorporated in image forming equipment for adjusting the output of an image density sensor which optically senses the density of a toner image formed on a photoconductive element and representative of a reference pattern. The density sensor is made up of a light emitting element and a light-sensitive element. Thresholds divide an output range wherein the output characteristic of the sensor does not change into a plurality of subranges having the optimal output associated with the background of the photoconductive element as the center value. The sensor senses the background of the photoconductive element at predetermined intervals. Whether or not to adjust the output of the sensor is determined on the combination of the subrange where the resulting output of the sensor lies and the number of times that the former lies in the latter. The sensor output, i.e., a PWM (Pulse Width Modulation) duty to be fed to the light emitting element is changed to control the adjusted output associated with the background to the optimal value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.