Photocopying – Projection printing and copying cameras – Identifying – composing – or selecting
Reexamination Certificate
2003-06-10
2004-06-01
Nguyen, Henry Hung (Department: 2851)
Photocopying
Projection printing and copying cameras
Identifying, composing, or selecting
C355S047000
Reexamination Certificate
active
06744491
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of and an apparatus for recording a two-dimensional image on a photosensitive medium by exposure to light beams which are emitted from a plurality of light sources arrayed in an auxiliary scanning direction and applied to scan the photosensitive medium in a main scanning direction and the auxiliary scanning direction.
2. Description of the Related Art
There have been used exposure recording apparatus in which a drum with a photosensitive medium mounted on its outer circumferential surface is rotated about its own axis in a main scanning direction and the photosensitive medium is scanned with a laser beam that has been modulated by an image to be recorded, in an auxiliary scanning direction perpendicular to the main scanning direction, for thereby recording a two-dimensional image on the photosensitive medium.
One type of such exposure recording apparatus has a plurality of light sources arrayed in the auxiliary scanning direction which can simultaneously be energized to record a large-size image at a high speed (see Japanese laid-open patent publication No. 7-23195). If the positions of images produced by adjacent ones of the light sources are inaccurate relatively to each other, then junctions between recording ranges of the light sources suffer from striped image irregularities or artifact.
According to the above conventional exposure recording apparatus, if the positions of images produced by the light sources are misaligned in the main scanning direction, then such a positional misalignment is corrected by delaying or advancing the recording times of the light sources in the main scanning direction by a certain relative period. If the positions of images produced by the light sources are misaligned in the auxiliary scanning direction, then times to start or complete recording images in the auxiliary scanning direction by the respective light sources are shifted by the number of pixels that is obtained by rounding off the image position misalignment, for thereby correcting a misalignment that is equal to or greater than one half of a pixel, and the speed of movement of the light sources in the auxiliary scanning direction is partially adjusted to form an overlap between pixels, for thereby correcting a misalignment that is less than one half of a pixel.
In the above conventional exposure recording apparatus, since pixels represented by the same image information overlap each other in correcting a misalignment that is less than one half of a pixel, an image irregularity due to the pixel overlap is visually recognized. Consequently, the correcting process according to the conventional exposure recording apparatus is too rough and should not be applied to a process of forming highly accurate images such as on printed materials for commercial use.
SUMMARY OF THE INVENTION
It is a general object of the present invention to provide a method of and an apparatus for recording a high-quality image at a high speed.
A major object of the present invention is to provide a method of and an apparatus for recording an image by exposure to light beams which are emitted from a plurality of simultaneously energized light sources arrayed in an auxiliary scanning direction, without producing striped image irregularities or artifact between images recorded by the respective light sources.
Another object of the present invention is to provide a method of and an apparatus for recording an image by joining images well in an auxiliary scanning direction with an inexpensive arrangement without the need for mechanical or optical adjustments.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way of illustrative example.
REFERENCES:
patent: 5453777 (1995-09-01), Pensavecchia et al.
patent: 5982402 (1999-11-01), Yoshikawa et al.
patent: 6141030 (2000-10-01), Fujita et al.
patent: 6188466 (2001-02-01), Iwasa et al.
patent: 6249306 (2001-06-01), Isono et al.
patent: 7-23195 (1995-01-01), None
Ikematsu Teruji
Miyagawa Ichirou
Ozaki Takao
Suganuma Atsushi
Uemura Takayuki
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