Method and apparatus for generating gray tones in an ink jet printer
US4065773A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 5, 1976 |
| Grant date | Dec 27, 1977 |
| Priority date | — |
| Expiry date | Apr 5, 1996 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J2/185
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The illustrated printer effectively divides the surface of a paper into a large number of small areas termed dot locations each of which may or may not receive one or more ink drops depending upon the tonal level to be printed. Fifteen tonal shades are utilized with the tonal scale evenly divided by averaging the number of drops over a given number of dot locations to effectively generate fractional drop intensities. Selected ink drops generated by an ink jet are charged as determined by an incoming signal and the charged droplets directed at selected dot locations on the paper. The charge duration is not related to the frequency of the ink drop generation and further, the time of initiation of the drop charging period and the ink drop frequency are asynchronous. Thus, for a given charging period, a varying number of ink drops will be charged resulting in an averaging of the ink drops over several dot locations corresponding to a single tonal value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.