Method and apparatus for position referencing the rotating drum of a scanner/plotter
US4024518A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 14, 1975 |
| Grant date | May 17, 1977 |
| Priority date | — |
| Expiry date | Nov 14, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/2457
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus are disclosed for referencing the position of a rotatable drum in a scanner/plotter. The rotatable drum is rotatable held in axial alignment by means of a drum headstock and a spring loader, moving center tailstock. An optical shaft encoder provides a reference pulse for the headstock drum shaft and a plurality of drive shaft position pulses. The rotatable drum has a magnetic pellet mounted thereon. A magnetic transducer is positioned with respect to the predetermined drive shaft position to detect the presence of the drum pellet. As the drum rotates, the transducer detects the pellet and produces an output signal which is used to electronically cross-reference the drum pellet to the predetermined drive shaft position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.