Photocopying – Projection printing and copying cameras – Identifying – composing – or selecting
Reexamination Certificate
1998-11-12
2001-03-13
Adams, Russell (Department: 2851)
Photocopying
Projection printing and copying cameras
Identifying, composing, or selecting
C355S040000, C347S238000
Reexamination Certificate
active
06201596
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an exposure method and device, and particularly to an exposure method and device which effects exposure by light emitting elements such as LED chips or laser diode (LD).
2. Description of the Related Art
Conventionally, in an image recording apparatus such as a printer, in which an image is exposed onto a photosensitive material based on image data and an image recorded by the exposure on the photosensitive material is transferred to a plain paper and is outputted, an exposure device is used in which light emitting elements such as LED chips or LD, which are used for exposure of the photosensitive material, are provided in a light source portion.
In such conventional image recording apparatus, in order to allow high-speed recording of an image on a photosensitive material, a plurality of light emitting elements are provided in a light source portion along a sub-scan direction and a plurality of scanning lines are simultaneously formed in the sub-scan direction at one main scan operation, thereby allowing recording of an image.
In the above-described conventional image recording apparatus having a plurality of light emitting elements, it is necessary that the plurality of light emitting elements be mounted correctly to predetermined positions along a sub-scan direction of the light source portion so that exposure positions of the plurality of light emitting elements on the photosensitive material, which are provided along the sub-scan direction, are arranged on the same straight line along the sub-scan direction. However, these light emitting elements are not necessarily mounted to correct positions due to positional errors of mounted light emitting elements in a production process of the light source portion or due to displacement of the mounted positions of the light emitting elements caused by environmental variation after the production, or the like.
When the plurality of light emitting elements are not mounted to correct positions in the light source portion, these light emitting elements cannot be caused to emit light so that exposure positions of the light emitting elements on the photosensitive material are arranged on the same straight line along the sub-scan direction. As a result, there exists a drawback in that the quality of an image obtained finally deteriorates.
SUMMARY OF THE INVENTION
The present invention has been devised so as to solve the above-described drawback, and an object thereof is to provide an exposure method and device which can prevent deterioration in the quality of an image, which is caused by positional errors of mounted light emitting elements.
A first aspect of the present invention is an exposure device comprising: a light source portion in which a plurality of light emitting elements are mounted along a predetermined direction and which is moved in a direction perpendicular to the predetermined direction during exposure; storage means which stores a value corresponding to positional errors of the plurality of mounted light emitting elements in the direction perpendicular to the predetermined direction; and determination means which determines, based on the value corresponding to the positional errors stored in the storage means, a timing at which the plurality of light emitting elements are caused to emit light for each of the light emitting elements so that exposure positions obtained by the plurality of light emitting elements are arranged on the same line along the predetermined direction.
In the exposure device according to the first aspect of the present invention, a plurality of light emitting elements are mounted along a predetermined direction in a light source portion moved in a direction perpendicular to the predetermined direction during exposure, and a value corresponding to positional errors of the plurality of light emitting elements in the direction perpendicular to the predetermined direction is stored in the storage means. Meanwhile, the value corresponding to positional errors of the plurality of mounted light emitting elements can be obtained by directly measuring the mounted positions of the plurality of light emitting elements mounted in the light source portion or by actually recording an image using the exposure device of the present invention and measuring the position of the image.
Subsequently, when exposure is actually effected, based on the value corresponding to the errors stored in the storage means, the timing at which the plurality of light emitting elements are caused to emit light is determined by the determination means for each light emitting element so that exposure positions obtained by the plurality of light emitting elements are arranged on the same line along the predetermined direction. Meanwhile, when an object to be exposed has the shape of a bed, the above-described same line becomes the same straight line. Further, when an object to be exposed has the shape of a drum, the above-described same line becomes the same circumferential line.
As described above, according to the first aspect of the present invention, the timing at which the plurality of light emitting elements are caused to emit light is determined for each light emitting element so that exposure positions obtained by the plurality of light emitting elements are arranged on the same line along the predetermined direction, and therefore, deterioration in image quality caused by positional errors of the mounted light emitting elements can be prevented.
Further, a second aspect of the present invention is an exposure method comprising the steps of: storing in advance a value corresponding to positional errors of a plurality of light emitting elements, which are mounted in a light source portion along a predetermined direction, in a direction perpendicular to the predetermined direction, the light source portion being moved in the direction perpendicular to the predetermined direction during exposure; and based on the value corresponding to the positional errors and stored in advance, determining, for each of the plurality of light emitting elements, a timing at which the plurality of light emitting elements are caused to emit light so that exposure positions obtained by the plurality of light emitting elements are arranged on the same line along the predetermined direction.
In the exposure method according to the second aspect of the present invention, a plurality of light emitting elements are mounted along a predetermined direction in a light source portion moved in a direction perpendicular to the predetermined direction during exposure, and a value corresponding to positional errors of the plurality of light emitting elements in the direction perpendicular to the predetermined direction is stored in advance. Meanwhile, the value corresponding to positional errors of the plurality of light emitting elements can be obtained by directly measuring the mounted positions of the plurality of light emitting elements mounted in the light source portion or by actually recording an image using the exposure device of the present invention and measuring the position of the image.
Subsequently, when exposure is actually effected, based on the value corresponding to the errors stored in advance, the timing at which the plurality of light emitting elements are caused to emit light is determined for each of the light emitting elements so that exposure positions of the plurality of light emitting elements are arranged on the same line along the predetermined direction. Meanwhile, when an object to be exposed has the shape of a bed, the above-described same line becomes the same straight line. Further, when an object to be exposed has the shape of a drum, the above-described same line becomes the same circumferential line.
As described above, according to the second aspect of the present invention, the timing at which the plurality of light emitting elements are caused to emit light is determined for each light emitting element so that exposure positions of the plura
Adams Russell
Fuji Photo Film Co. , Ltd.
Nguyen Hung Henry
Sughrue Mion Zinn Macpeak & Seas, PLLC
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