Apparatus and method for controlling coalescence of ink drops on a print medium
US5600352A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 1994 |
| Grant date | Feb 4, 1997 |
| Priority date | — |
| Expiry date | Jun 27, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K15/102
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An image transfer ink-jet printer (10) employs an image receiving drum (12) that rotates relative to a ink-jet array print head (26) spanning the full width of the drum. An encoder disk (70) is coupled to the drum to coordinate ink drop ejection with precise angular rotational increments of the drum. The encoder disk has an alternating transparent/opaque pattern with a pitch that is one-half the desired resolution of the printer. A photo-optical detector (72) senses the alternating pattern and sends an asymmetrical signal to a duty-cycle correction circuit (140) that generates a symmetrical signal having a frequency double the one received from the photo-optical detector. The symmetrical signal is processed by a dot clock circuit (180) that applies programmable time delays to selected ones of the dot clock pulses (122, 124) to produce ink drop positioning patterns (130, 132) that control the coalescence of adjacent ink drops (80) without reducing overall printer resolution or producing undesired image artifacts. The coalesced ink drops (100) have a shape suitable for depositing multiple ink layers that produce well saturated color images in transparency projection applications.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.