Mark detection circuit for an electrographic printing machine
US5339150A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 23, 1993 |
| Grant date | Aug 16, 1994 |
| Priority date | — |
| Expiry date | Mar 23, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/506
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method of adjusting an imager in an electrophotographic printing machine to correct for registration errors when forming a composite image. Registration errors are sensed by forming one or more target lines on the photoreceptor surface, detecting the center of the lines and controlling the operation of the imager in response thereto. In one embodiment, four LED print bars form a composite color image in a single pass. A photosensor is placed beneath the print bars; a narrow target line is formed on the belt surface a few scan lines before the start of an exposure frame. The center of the line is detected by circuitry connected to the sensor output which produces a signal corresponding to detection of the center of the target line. This output signal is generated for each of the three downstream print bars and a signal is applied to each print bar to start the image exposure sequence in registration with first image exposure. In a second embodiment, skew registration adjustments are enabled by forming two line marks at opposite ends of the photoreceptor, detecting the center of each mark and making the adjustments of the position of the downstream print bars based o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.