Sheet feeder synchronization system having error correction means
US4835698A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 1987 |
| Grant date | May 30, 1989 |
| Priority date | — |
| Expiry date | Jul 7, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/0022
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and corresponding apparatus for identifying a series of lengths along a moving web are disclosed, especially for use in registering sheets with the web. The method is used with a device operating on the web including an element rotating synchronously with advance of the web. The method includes generating a data signal in response to rotation of the element, the signal including a series of pulses, with each pulse corresponding to an increment of rotation. A first of the lengths is converted to a first real number of increments, which number is adjusted to a first integer number of increments. The error is retained. A first length is then identified as corresponding to the first integer number of increments within the data signal. A second length is then converted to a second real number of increments. This value is adjusted to an integer number, and the cumulative error is used to correct the value if necessary. The second length is identified along the web as corresponding to the second integer number of increments within the data signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.