Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
1999-09-24
2003-01-28
Pham, Hai (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S257000
Reexamination Certificate
active
06512533
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an scanning optical device comprising at least a light source, a collimator lens into which a light beam emitted from said light source enters, a deflector which deflects the light beam having passed said collimator lens to the direction of main scanning, and an image forming lens which focuses the light beam having passed said deflector on the surface to be scanned and to an image forming apparatus having a plurality of the above-mentioned scanning optical devices arranged in the direction of sub-scanning.
Generally speaking, in an image forming apparatus capable of forming a multi-color image, a cylinder-shaped, or belt-shaped image bearing member is used. In forming a multi-color image by using this image bearing member, charging, exposure, and development are carried out for each of colors with the image bearing member rotated (moved), and the multiple color toner images are superposed one after another on the image bearing member and transferred onto a sheet of transfer paper by a one-time transfer operation.
Incidentally, in order to accomplish a high-speed printing, it is not required to have a structure such that exposure processing (writing by light) for one color is carried out in every rotation of the image bearing member. Instead a structure can be used such that the exposures for all of four colors Y, M, C, and K are carried out in every rotation of the image bearing member. In this case, not only a plurality of the developing units but also a plurality of the scanning optical devices corresponding to the respective colors should be provided in order that the multiple exposures and developments should be done at different positions on the image bearing member.
For example, in the case where a color image is formed using the four colors Y (yellow), M (magenta), C (cyan), and K (black), the scanning optical devices and the developing units for the respective colors Y, M, C, and K are arranged in the direction of sub-scanning, and each of the scanning optical devices is let to form the latent electrostatic image of the color corresponding to it in such a manner as to form the toner images precisely superposed on one another, and the latent electrostatic images are developed.
In this case, with respect one pixel of the latent images formed by the respective scanning optical devices, if the position of this pixel is deviated for a certain color, synthesis of the color can not be done at this pixel portion, producing a color deviation and lowering resolution, and image quality is deteriorated. In order to prevent the occurrence of this color deviation and the lowering of resolution, it is required that not only the characteristics of the respective scanning optical devices are made to be the same so as to be able to write the same scan line, but also that the respective optical devices are fixed in a precise positional relationship so as to make the scan lines for the respective colors coincide with one another.
To consider the characteristics of an individual scanning optical device, it is desirable for obtaining a good image that the scan lines on the surface to be scanned are straight and, that at the same time, the arrangement of the pixels forming any one of the scan lines has a uniform interval between any adjacent pixels. However, actually, the positioning of optical parts etc can not be precisely performed. Therefore, there have been problems that scan lines on the surface to be scanned are curved and that the arrangement of the pixels forming a scan line has an uneven interval between pixels.
Further, in the case where a multi-color image is formed, there has been a problem that the characteristics of the respective scanning optical devices can not be made equal, and that the respective scanning optical devices cannot be fixed in a precise positional relationship, resulting in deterioration of image quality.
SUMMARY OF THE INVENTION
This invention has been made in order to solve the above-described problems, and it is an object of this invention concerning a scanning optical device to actualize a scanning optical device capable of adjusting the scanning beam easily.
Further, it is an object of this invention concerning an image forming apparatus to actualize an image forming apparatus capable of getting rid of the deterioration of image quality owing to the scanning optical device.
The above object can be attained by the following structures.
A scanning optical system, comprises:
a plurality of scanning optical devices, each scanning optical device including
a light source to emit a light beam,
a collimator lens into which the light beam emitted from the light source enters,
a deflector to deflect the light beam passing through the collimator lens in a main scanning direction,
an image forming lens to focus the light beam coming from the deflector onto a scanned surface, and
a base plate on which the light source, the collimator lens, the deflector and the image forming lens are fixed, wherein the plurality of scanning optical devices are piled up in a sub-scanning direction perpendicular to the main scanning direction in such a manner that each base plate is substantially parallel to other base plates; and
a plurality of link members to connect two neighboring base plates independently of other base plates.
A scanning optical system, comprises:
a plurality of scanning optical devices, each scanning optical device including
a light source to emit a light beam,
a collimator lens into which the light beam emitted from the light source enters,
a deflector to deflect the light beam passing through the collimator lens in a main scanning direction,
an image forming lens to focus the light beam coming from the deflector onto a scanned surface,
a contact member to come in contact with a first side surface of the image forming lens at three contact points on both end portions and a middle portion of the first side surface in terms of the main scanning direction;
a pressing member to come in pressure contact with a second side surface of the image forming lens so as to press the image forming lens toward the contact member and
a base plate on which the light source, the collimator lens, the deflector, the image forming lens, the contact member and the pressing member are fixed, wherein the plurality of scanning optical devices are piled up in a sub-scanning direction perpendicular to the main scanning direction in such a manner that each base plate is substantially parallel to other base plates; and
a plurality of link members to connect two neighboring base plates independently of other base plates.
A scanning optical device, comprises:
a light source to emit a light beam;
a collimator lens into which the light beam emitted from the light source enters;
a deflector to deflect the light beam passing through the collimator lens in a main scanning direction;
an image forming lens to focus the light beam coming from the deflector onto a scanned surface;
a contact member to come in contact with a first side surface of the image forming lens at three contact points on both end portions and a middle portion of the first side surface in terms of the main scanning direction; and
a pressing member to come in pressure contact with a second side surface of the image forming lens so as to press the image forming lens toward the contact member.
Further, the above object can be attained by the following preferable structures.
A scanning optical device comprising at least a light source, a collimator lens into which a light beam emitted from said light source enters, a deflector which deflects the light beam having passed said collimator lens to the direction of main scanning, and an image forming lens which focuses the light beam having passed said deflector on the surface to be scanned, said scanning optical device further comprising contact members capable of being in contact with said image forming lens at three points, that is, the both end portions of said image forming lens in the direction of main scanning and an intermedia
Suzuki Takeshi
Tajima Naoki
Tanoue Kazuyuki
Frishauf Holtz Goodman & Chick P.C.
Konica Corporation
Pham Hai
LandOfFree
Image forming apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image forming apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image forming apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3044212