Variable magnification copier
US4903079A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 24, 1988 |
| Grant date | Feb 20, 1990 |
| Priority date | — |
| Expiry date | Aug 24, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/041
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A variable magnification scanning optical system for a copying machine includes a lens (10) for projecting an image of an original document (2) with a pre-selected magnification onto a moving imaging member (6). The scan speed may be varied relative to the speed of the imaging member to alter the magnification in the scan direction. To this end a reference signal is generated which is derived from the imaging member and is indicative of the nominal pre-selected magnification. A second signal is generated indicative of the scan speed and the scan speed is varied, e.g. by a servo system (see FIG. 2), until the second signal matches the reference signal. To compensate for tolerances between the nominal magnification and the actual magnification, the reference signal may be adjusted by applying an offset value (23) stored in the memory. This offset value may be entered into the memory by an operator via a keyboard panel (22). Also, compensation may be made independently for magnification tolerances in the cross-scan direction, again by the application of an offset value stored in a memory, to move the lens from its home position corresponding to nominal unity magnification to a new pos…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.