Image forming apparatus and method for controlling tone characteristics based on tone-control patch image
US7680425B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 16, 2004 |
| Grant date | Mar 16, 2010 |
| Priority date | — |
| Expiry date | Dec 21, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/0177
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image It is formed as a patch image which includes a header image portion Ih of a solid image having a length of a circumferential length of a developing roller or more, and a gradation image portion Ig progressively varied in the tone level thereof from the maximum level to the minimum level. The densities of the patch image on an intermediate transfer belt are sampled. However, the sampling results contain errors resulting from noises or variations and hence, are subjected to a noise removal process, a periodical variation correction process and a reverse correction process. The results detected on the intermediate transfer belt do not always coincide with image densities (OD values) on a recording material. Therefore, the detection results are converted into the OD values, based on which tone characteristics of an apparatus is estimated. Then a tone correction table is updated in a manner to compensate for the tone characteristics. This approach is taken to improve image quality on the recording material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.