Exposing device for correcting an f.theta. error of a rotatable polygon mirror without using an f.theta. lens
US5963243A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 8, 1994 |
| Grant date | Oct 5, 1999 |
| Priority date | — |
| Expiry date | Nov 8, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K15/1223
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An exposing device is composed of a photosensitive drum having a surface partitioned into a plurality of exposure areas in a main scanning direction, for carrying an image formed by exposing the surface, a laser light source for emitting a laser beam, a polygon mirror for rotating at a constant speed to scan the surface of the photosensitive drum in the main scanning direction with the laser beam from the laser light source, and an exposure control circuit for producing items of emission data for one line while the number of emission data items for one dot is varied for each exposure area, and for supplying the emission data items for one line to the laser light source in response to a print clock pulse. Particularly, the exposure control circuit includes a CPU for multiplying a reference value for the number of data items which should be selected from emission data items for a dot and changed in value to obtain a predetermined function, by a coefficient for an exposure area to which the emission data items for the dot are assigned, and for changing the value of each data item selected from the emission data items for the dot in number corresponding to a result of multiplication.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.