Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Reexamination Certificate
1998-09-21
2001-05-08
Spyrou, Cassandra (Department: 2872)
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
C359S196100, C359S197100, C359S199200, C359S200700, C310S06700R, C310S091000, C310S216055, C347S260000
Reexamination Certificate
active
06229637
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotary apparatus usable as a driver in a rotary mechanism used in a light deflector of an image forming apparatus in a digital copying machine, a laser beam printer, or the like, and a deflection-scanning apparatus using the rotary apparatus.
2. Related Background Art
FIG. 1
is a view illustrating the overall structure of a scanning optical system with a deflection-scanning apparatus. As illustrated in
FIG. 1
, a laser unit
2
is mounted in an optical box
1
, a rotary polygonal mirror
3
of the deflection-scanning apparatus and lenses
4
and
5
are arranged along an optical path L emerging from the laser unit
2
in the optical box
1
, and a photosensitive member
6
of a recording medium is disposed outside of the optical box
1
.
Laser light emerging from the laser unit
2
is deflected by the rotary polygonal mirror
3
rotatably supported by a bearing apparatus, transmitted through the lenses
4
and
5
and projected as a light spot on the photosensitive member
6
disposed outside of the optical box
1
. A main scan is thus performed.
In the vicinity of the photosensitive member
6
, there are arranged a corona discharger for uniformly electrifying a surface of the photosensitive member
6
, a developing unit for visualizing an electrostatic latent image formed on the surface of the photosensitive member
6
to obtain a toner image, a transferor for transferring the toner image to a recording paper, and the like. Recording information of the laser light generated by the laser unit
2
is thus printed on the recording paper or the like.
For example, in a deflection-scanning apparatus as illustrated in
FIG. 2
which is disclosed in Japanese Patent Application Laid-Open No. 6-123850, a rotary polygonal mirror
3
is supported rotatably about a fixed shaft
31
through a flange
27
and is rotatable at a high speed by means of a magnetic action between a permanent magnet
30
on a rotor side and a yoke
32
with an electromagnetic coil
33
on a stator side opposed to the rotor side.
However, since the yoke
32
is supported in a cantilever manner, vibrations occur due to the rotation of the rotor caused by a change of poles. The vibration adversely influences a life of the rotary apparatus and a deflection precision of the beam deflected by the deflection-scanning apparatus.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a rotary apparatus in which a vibration due to its rotation is difficult to occur.
Another object of the present invention is to provide a deflection-scanning apparatus which uses the rotary apparatus to enhance a precision of a beam deflection.
A rotary apparatus of the present invention for achieving the above object includes a stator portion, a rotor portion which is rotatably supported by the stator portion and includes a permanent magnet, a ring-shaped stator core which is arranged opposingly to the permanent magnet and includes a plurality of electromagnetic coils wound around a plurality of locations of the stator core discretely existing along its circumferential direction, and a ring member which supports a free end of the stator core.
Further, in a deflection-scanning apparatus of the present invention for achieving the above object, a deflector, such as a rotary polygonal mirror, is rotated by a rotary apparatus, which includes a stator portion, a rotor portion which is rotatably supported by the stator portion and includes a permanent magnet, a ring-shaped stator core which is arranged opposingly to the permanent magnet and includes a plurality of electromagnetic coils wound around a plurality of locations of the stator core discretely existing along its circumferential direction, and a ring member which supports a free end of the stator core.
REFERENCES:
patent: 4763199 (1988-08-01), Suzuki
patent: 4878068 (1989-10-01), Suzuki
patent: 4905023 (1990-02-01), Suzuki
patent: 5365259 (1994-11-01), Kanoto et al.
patent: 5642150 (1997-06-01), Takahashi
patent: 5670837 (1997-09-01), Boutaghou et al.
patent: 5731831 (1998-03-01), Murabe et al.
patent: 5831363 (1998-11-01), Fukita et al.
patent: 5835124 (1998-11-01), Fukita et al.
patent: 6-123850 (1994-05-01), None
Fukita Taku
Suzuki Yasuo
Canon Kabushiki Kaisha
Curtis Craig
Fitzpatrick ,Cella, Harper & Scinto
Spyrou Cassandra
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