Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
2000-09-27
2002-10-29
Pham, Hai (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S242000
Reexamination Certificate
active
06473113
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a scanning optical apparatus to be suitably used for a laser beam printer, a laser facsimile machine or the like.
2. Related Background Art
FIGS. 9 and 10
schematically illustrate a known scanning optical apparatus of the type under consideration.
FIG. 9
is a schematic plan view of the apparatus, showing various parts arranged in an optical cabinet, and
FIG. 10
is a schematic cross sectional view taken along line
10
—
10
in FIG.
9
. As shown in FIGS
9
and
10
, optical cabinet
1
contains therein a laser unit
2
, a composite lens
3
, a rotary polygon mirror
4
, a drive motor
5
, a first imaging lens
6
, a second imaging lens
7
and a surface reflector (fold mirror)
8
along with other elements and the top opening of the optical cabinet
1
is covered by a lid
9
. The laser unit
2
comprises a semiconductor laser beam source
2
a
, a collimator lens
2
b
, a photodetector section
2
c
and other components, while the composite lens
3
comprises a cylindrical lens
3
a
and a beam detecting lens
3
b
. The rotary polygon mirror
4
is provided with deflection/reflection planes
4
a
and driven to rotate by the drive motor
5
.
As seen from
FIGS. 9 and 10
, the first imaging lens
6
is rigidly secured to the optical cabinet
1
by means of a pair of leaf springs
10
,
11
and the second imaging lens
7
is rigidly secured to the optical cabinet
1
also by means of a pair of leaf springs
12
,
13
. The leaf springs
10
through
13
are arranged in respective spring securing sections
14
,
15
,
16
,
17
of the optical cabinet located at the light exiting sides of the imaging lenses
6
,
7
so that the latter are urged toward the light entering sides thereof.
The first imaging lens
6
is typically provided with;upper and lower flange sections
6
a
,
6
b
of which the lower flange section
6
b
have a projection
6
c
projecting from the longitudinal center thereof for the purpose of centering the first imaging lens
6
. Additionally, the first imaging lens
6
is provided at the longitudinal opposite ends thereof with respective upright direction reference planes
6
d
,
6
d
that are arranged at the lower flange section
6
b
, while an optical axial direction reference plane
6
e
is arranged at the light entering side of the lens
6
.
The optical cabinet
1
is provided with an opening
1
a
for allowing the laser beam reflected by the surface reflector
8
to pass therethrough, a pair of positioning pins
1
b
,
1
b
for pinching the projection
6
c
of the first imaging lens
6
, an upright direction reference section
1
c
on which the upright direction reference planes
6
d
,
6
d
of the first imaging lens
6
abut, a rib-shaped optical axial direction reference section
1
d
on which the optical axial direction reference plane
6
e
of the first imaging lens
6
abuts and an anchor claw for anchoring the leaf springs
10
.
The leaf spring
12
is made to show a profile that corresponds to that of the second imaging lens
7
and the leaf springs
11
,
13
are arranged symmetrically relative to the corresponding leaf springs
10
,
12
. Additionally, the spring securing section
16
is made to show a profile that corresponds to that of the leaf spring
12
and the spring securing sections
15
,
17
are arranged symmetrically relative to the corresponding spring securing sections
14
,
16
.
With the above described known optical scanning apparatus, a total of four leaf springs
10
through
13
having respective profiles that are different from each other are required in order to rigidly secure the imaging lenses
6
,
7
to the optical cabinet
1
. So many leaf springs may by turn require a large number of assembling and disassembling steps and cumbersome control procedures. Additionally, since the spring securing sections
14
through
17
are respectively subjected to the reactions of the urging forces of the leaf springs
10
through
13
, large power is required when, fitting the leaf springs
10
through
13
to the optical cabinet
1
.
SUMMARY OF THE INVENTION
In view of the above identified problems of the prior art, it is therefore the object of the present invention to provide an optical scanning apparatus that comprises a reduced number of components and whose imaging lenses can be mounted and dismounted with ease.
According to the invention, the above object is achieved by providing a scanning optical apparatus comprising a light emitting means adapted to emit a laser beam, a deflection means for deflecting the laser beam from said light emitting means and a pair of imaging lenses adapted to scan a photosensitive member by the laser beam from the deflection means, the abutment reference planes of the optical axial direction of said imaging lenses being arranged at the back sides of said imaging lenses relative to the oppositely disposed respective surfaces of the lenses.
In another aspect of the invention, there is provided a scanning optical apparatus comprising a light emitting means adapted to emit a laser beam, a deflection means for deflecting the laser beam from said light emitting means and a pair of imaging lenses adapted to scan a photosensitive member by the laser beam from the deflection means, the abutment reference planes of the optical axial direction of said imaging lenses being arranged at the oppositely disposed respective surfaces of the lenses.
In still another aspect of the invention, there is provided a scanning optical apparatus comprising a light emitting means adapted to emit a laser beam, a deflection means for deflecting the laser beam from said light emitting means, first and second imaging lenses adapted to scan a photosensitive member by the laser beam from the deflection means and an urging member for urging said first and second imaging lenses, said urging member being adapted to urge said second imaging lens in a direction opposite to the direction of urging said first imaging lens.
In a further aspect of the invention, there is provided a scanning optical apparatus comprising a light emitting means adapted to emit a laser beam, a deflection means for deflecting the laser beam from said light emitting means, first and second imaging lenses adapted to scan a photosensitive member by the laser beam from the deflection means and an urging member for urging said first and second imaging lenses, said urging member being adapted to urge one or more than one optical components in addition to urging said first and second imaging lenses.
REFERENCES:
patent: 5499045 (1996-03-01), Takeshita et al.
patent: 5600495 (1997-02-01), Sekikawa
Canon Kabushiki Kaisha
Pham Hai
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