Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Reexamination Certificate
2001-07-18
2003-06-03
Cherry, Euncha (Department: 2872)
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
C359S216100, C310S06700R
Reexamination Certificate
active
06574023
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a light-beam deflecting apparatus, in which a polygon mirror is pushed against a flange to hold it stationary, a manufacturing method of the light-beam deflecting apparatus and an image-forming apparatus.
Conventionally, electro-photographic image-forming apparatuses, such as laser-beam printers, digital copiers, etc., have employed a light-beam deflecting apparatus for scanning a light-beam, in order to write images onto a photoreceptor drum. In the conventional light beam deflection apparatus, a polygon mirror combined with magnets is rotatably inserted into a central axis of the base body with a bearing between them, and driving coils are disposed opposite the magnets so that a rotational torque, caused by the relative magnetic forces generated between the permanent magnets and the driving coils when electric currents flow into the driving coils, rotates the polygon mirror at a high rate, while forming an air gap between the base body and a rotating disk including the polygon mirror, etc.
In the abovementioned light-beam deflecting apparatus, since the polygon mirror is pushed against the flange to hold it stationary relative to the flange, contacting surfaces of both the polygon mirror and the flange should be finished as accurate surfaces to improve an inclined angle of a mirror surface of the polygon mirror. Such contacting surfaces are finished so that their surface roughness Ry is not greater than 1 &mgr;m (Ry≦1 &mgr;m). In the conventional configuration, however, in which both the contacting surfaces push against each other to fix the polygon mirror onto the flange, there has been a fear that the position of the polygon mirror possibly deviates from its original position due to a centrifugal force generated by high-speed rotation, resulting in unbalance of the mass distribution of the rotating disk and an increase of vibrations.
SUMMARY OF THE INVENTION
To overcome the abovementioned drawbacks in the conventional light-beam deflecting apparatus, it is an object of the present invention to provide a light-beam deflecting apparatus which makes it possible to prevent the polygon mirror from deviating from the original position and to stably rotate the polygon mirror, even if the polygon mirror, pushed against the flange, rotates at a high rate during its operating time. It is also an object of the present invention to provide a method for manufacturing such light-beam deflecting apparatus, and further to provide an image-forming apparatus equipped with such light-beam deflecting apparatus.
Accordingly, to overcome the cited shortcomings, the abovementioned object of the present invention can be attained by a light-beam deflecting apparatus, methods for manufacturing the light-beam deflecting apparatus and image-forming apparatus described as follows.
(1) A light-beam deflecting apparatus, comprising: a base member; a polygon mirror being rotatable in respect to the base member; a flange contacting the polygon mirror to hold the polygon mirror; and a pushing member to push the polygon mirror against the flange; wherein one or both of contacting surfaces of the polygon mirror and the flange is/are finished to a surface roughness of Ry, which fulfills a first formula of Ry≧3 &mgr;m.
(2) The light-beam deflecting apparatus of item
1
, wherein surface roughness Ry fulfills a second formula of 3 &mgr;m≦Ry≦20 &mgr;m.
(3) The light-beam deflecting apparatus of item
1
, wherein one or both of contacting surfaces of the polygon mirror and the flange is/are finished to surface roughness Ry, by employing one of an abrasive blasting, a cutting machining, a laser machining, a dry ice blasting, a chemical processing and a form rolling, or by employing a combination of a plurality of machining methods arbitrarily selected from them.
(4) A method for manufacturing a light-beam deflecting apparatus, which incorporates a polygon mirror being rotatable in respect to a base member and a flange contacting the polygon mirror to hold the polygon mirror, comprising the steps of: finishing one or both of contacting surfaces of the polygon mirror and the flange to a surface roughness of Ry, which fulfills a first formula of Ry≧3 &mgr;m; and fixing the polygon mirror onto the flange by pushing the polygon mirror against the flange so that both of the contacting surfaces contact each other with a pushing force applied, in order to assemble the light-beam deflecting apparatus.
(5) The method of item
4
, wherein surface roughness Ry fulfills a second formula of 3 &mgr;m≦Ry≦20 &mgr;m.
(6) The method of item
4
, wherein one or both of the contacting surfaces is/are finished to surface roughness Ry, by employing one of an abrasive blasting, a cutting machining, a laser machining, a dry ice blasting, a chemical processing and a form rolling, or by employing a combination of a plurality of machining methods arbitrarily selected from them.
(7) The method of item
4
, wherein one or both of the contacting surfaces is/are finished to surface roughness Ry, which fulfills a third formula of Ry<3 &mgr;m, before performing the finishing step.
(8) An image-forming apparatus, comprising: a photoreceptor; and the light-beam deflecting apparatus cited in item
1
; wherein a light-beam, reflected from the polygon mirror, writes image information on the photoreceptor.
(9) The image-forming apparatus of item
8
, wherein surface roughness Ry fulfills a second formula of 3 &mgr;m≦Ry≦20 &mgr;m.
(10) The image-forming apparatus of item
8
, wherein one or both of contacting surfaces of the polygon mirror and the flange is/are finished to surface roughness Ry, by employing one of an abrasive blasting, a cutting machining, a laser machining, a dry ice blasting, a chemical processing and a form rolling, or by employing a combination of a plurality of machining methods arbitrarily selected from them.
Further, to overcome the abovementioned problems, another light-beam deflecting apparatus and methods for manufacturing such light-beam deflecting apparatus, embodied in the present invention, will be described as follows:
(11) A light-beam deflecting apparatus, characterized in that, a base member, a polygon mirror rotating in respect to the base member, a flange contacting the polygon mirror to hold the polygon mirror and a pushing member to push the polygon mirror against the flange are provided, and a surface roughness (Ry) of one or both of contacting surfaces of the polygon mirror and the flange fulfills Ry≧3 &mgr;m.
According to the abovementioned light-beam deflecting apparatus, since a surface roughness (Ry) of at least one of contacting surfaces of the polygon mirror and the flange fulfills Ry≧3 &mgr;m, the frictional force between the contacting surfaces sufficiently increases when the polygon mirror is pushed against the flange to hold the polygon mirror, and thereby, the positional deviation of the polygon mirror, caused by the centrifugal force due to its high-speed rotating action during its operating time, hardly occurs, resulting in the stable rotation of the rotating disk without changing its vibration mode. Incidentally, in the present specification, the term of “surface roughness (Ry)” indicates the maximum height defined by JIS-B-0601.
It is desirable that the surface roughness (Ry) of the contacting surface fulfills the formula of 3 &mgr;m≦Ry≦20 &mgr;m. When the surface roughness (Ry) fulfills Ry ≦20 &mgr;m, it is possible to maintain the unit characteristics of the light-beam deflecting apparatus, such as the inclination angle of the mirror surface of the polygon mirror, etc., in an appropriate state. Further, the contacting surface can be finished to the abovementioned surface roughness (Ry), by employing one of an abrasive blasting, a cutting machining, a laser machining, a dry ice blasting, a chemical processing and a form rolling.
(12) A method for manufacturing a light-beam deflecting apparatus, characterized in that the method includes a process for finishing one or both of contacting surfaces
Kobayashi Hiroshi
Matsui Susumu
Miyakoshi Hiroshi
Ono Naohiro
Sasaki Katsuji
Cherry Euncha
Frishauf Holtz Goodman & Chick P.C.
Konica Corporation
LandOfFree
Light-beam deflecting apparatus, manufacturing method of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Light-beam deflecting apparatus, manufacturing method of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Light-beam deflecting apparatus, manufacturing method of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3107314