Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
2002-02-20
2004-05-11
Pham, Hai (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S243000
Reexamination Certificate
active
06734892
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optical deflection device that deflects light by means of a rotation of a polygon mirror and to an image forming apparatus equipped with the optical deflection device, and in particular, to an optical deflection device and an image forming apparatus in both of which the number of parts are reduced to make a substantial cost reduction possible.
In a conventional optical deflection device used as an optical scanning means in a writing unit of an image forming apparatus such as a laser printer, a laser copying machine, a laser facsimile machine and a combined machine including the foregoing, a polygon mirror is rotated at high speed, and a beam emitted from a light source composed of a semiconductor laser is deflected by the rotating polygon mirror so that an image recording medium such as a photoreceptor drum is scanned by the beam.
An example of the conventional optical deflection device stated above is shown in FIG.
8
. In this conventional optical deflection device, polygon mirror
200
is interposed between flange section
101
of body of rotation
100
and rotary yoke
102
to be incorporated solidly, and the body of rotation
100
in which the polygon mirror is incorporated is mounted rotatably on shaft portion
301
that is protruded on base
300
through bearing
400
, while, magnet
103
is arranged on the rotary yoke
102
to face coil
303
attached on base board
302
that is provided on the base
300
, thus, an electric current is made to flow through the coil
303
on the base
300
to rotate the body of rotation
100
through magnet
103
and thereby to rotate the polygon mirror
200
incorporated solidly in the body of rotation
100
.
In the conventional optical deflection device as in the foregoing, there are many parts used because the body of rotation
100
is fixed on the bearing
400
mounted on the shaft portion
301
of the base
300
, the polygon mirror
200
is incorporated in the flange section
101
of the body of rotation
100
, and the magnet
103
is arranged on the rotary yoke
102
that is provided to interpose the polygon mirror
200
between itself and the flange section
101
. Therefore, man-hour requirement for incorporating the polygon mirror
200
is great, resulting in a rise of manufacturing cost and a problem that an optical deflection device is made to be large.
SUMMARY OF THE INVENTION
With the background mentioned above, an object of the invention is to provide an optical deflection device wherein the number of parts needed to incorporate a polygon mirror is reduced sharply to achieve low cost and a small size of the optical deflection device and an image forming apparatus employing the optical deflection device.
Structure (1) to solve the problem stated above is represented by an optical deflection device having therein a body of rotation that is fixed on a bearing and is structured rotatably by a magnet arranged to face a coil provided on the base side, wherein the body of rotation is made of a magnet and a polygon mirror is fixed on the body of rotation.
Structure (2) is represented by the optical deflection device described in the Structure (1), wherein the body of rotation is made of a molded plastic magnet, and is fixed on the bearing through injection molding.
Structure (3) is represented by the optical deflection device described in the Structure (1), wherein the body of rotation is fixed on the bearing by means of either one of force fitting, shrinkage fitting and adhesion.
Structure (4) is represented by the optical deflection device described in the Structure (3), wherein the body of rotation is provided, on its portion that is in contact with the bearing, with a cut-out or irregularity.
Structure (5) is represented by the optical deflection device described in either one of the Structures (1), (2), (3) or (4), wherein the bearing is a dynamic pressure bearing.
Structure (6) is represented by the optical deflection device described in the Structures (5), wherein the dynamic pressure bearing is made of ceramic.
Structure (7) is represented by an image forming apparatus wherein light emitted from a light source is deflected by the optical deflection device described in either one of the Structures (1)-(6) to scan an image recording medium for recording images and thereby for forming images.
REFERENCES:
patent: 5754326 (1998-05-01), Kunii
patent: 5874793 (1999-02-01), Kuwayama et al.
patent: 8-93750 (1996-04-01), None
Kobayashi Hiroshi
Kurosawa Takaaki
Matsui Susumu
Konica Corporation
Pham Hai
Squire Sanders & Dempsey
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