Color printer halftoning method
US6250733A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 23, 1998 |
| Grant date | Jun 26, 2001 |
| Priority date | — |
| Expiry date | Nov 23, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/56
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of operating a printing system that can print any of several different colors onto a point on a sheet of printer media. The method includes using a halftoning screen with a matrix of assorted threshold values, along with image data having a matrix of image data elements. For each data element and each color, a density value is determined to establish the amount of each color needed to produce the color associated with the original data element. Then a calculation determines which of the colors will be printed to the particular location. In a selected sequence of colors, density values of the colors are added one by one to generate a density sum that increases until it exceeds the threshold value. The last color added, which caused the sum to exceed the threshold, is then printed to the media sheet at a corresponding point. The system may employ a high frequency blue noise screen, and may operate to print droplets of more colors than the number of ink colors by printing secondary color dots formed of two or more different color ink, as well as single color dots.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.