Dual-resolution encoding system for high cyclic accuracy of print-medium advance in an inkjet printer
US5598201A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1994 |
| Grant date | Jan 28, 1997 |
| Priority date | — |
| Expiry date | Jan 31, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J11/42
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The invention uses two very inexpensive rotary encoders in combination--a close-coupled one (or more) for high accuracy, and a remote-coupled one for high resolution. High-accuracy information is then combined with high resolution information in a digital processing system to yield composite information that is high in both accuracy and resolution. This information can be used to establish image positioning on a print medium. The overall system cost is lower than with an equivalent single encoder. Insidious cyclical errors in the coupling system (gear train or the like) are removable without expensive high tolerances and assembly or test fixtures. Residual cyclical error due to eccentric mounting or other error in the direct-coupled encoder scale also can be substantially removed, if desired, by adding another one or more encoders reading that scale, and suitably combining the information about that scale from the different sensors. The information is combined in such a way that the systematic cyclical errors cancel--or are quantified for use in explicit correction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.