Digital printer for avoiding moire patterns by using a dithering mask and angular rotation between print head and print medium to simulate analog printer halftoning of color images
US6738162B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 9, 1999 |
| Grant date | May 18, 2004 |
| Priority date | — |
| Expiry date | Dec 9, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/52
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A semi-digital printer includes a print head assembly that prints an image on a sheet of paper that has been mounted onto a turntable, and a rotating means which rotates the turntable so that the print head assembly ejects ink or toner onto the sheet of paper at one or more predetermined angles. The printing may be halftone or color. If the print head assembly includes more than one print head, the rotating means rotates the turntable to a different angle for each print head. By rotating the turntable in this manner, the printer records an image at any angle (0° to 360°) precisely (i.e., without having to perform the angular approximations required by conventional digital printers). As a result, a printed image of improved quality is produced. Alternatively, the semi-digital printer may be configured so that the print head assembly rotates relative to the paper.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.