Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
1999-06-24
2001-09-04
Tremblay, Mark (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C359S826000
Reexamination Certificate
active
06283371
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical scanner, and more particularly, the present invention relates to a lase
5
r diode module which is a light emitting section for focusing on a photosensitive drum.
2. Description of the Related Art
An optical scanner which is generally applied to a laser printer, as shown in
FIGS. 1 and 2
, includes a housing
1
in which is disposed a light emitting section, that is, a laser diode module serving as a light source.
The laser diode module comprises a laser diode
3
for generating a laser beam, a collimator lens
4
for shaping laser beams emitted from the laser diode
3
into parallel beams, and a slitted member
5
formed with a rectangular hole
5
a
for passing therethrough only a portion of shaped parallel light beams.
Along paths of the beams passed through the slitted member
5
, there are disposed a cylindrical leans
6
for converging the emitted beams into a sub scanning direction and a polygon mirror
7
having a plurality of reflecting faces for reflecting the beams passed through the cylindrical leans
6
at a predetermined angle of view while being rotated at a high speed.
Also, in front of the polygon mirror
7
, there is positioned an f-&thgr; lens, that is, a scanning lens
8
for spotting the beams onto a photosensitive drum
9
. The canning lens
8
comprises a toric lens
8
a
and a focusing leans
8
b
which is an aspherical lens.
Hereafter, operations of the optical scanner constructed as mentioned above will be described in detail.
If a beam is emitted from the laser diode
3
constituting the laser diode module, the beam is converged into the sub scanning direction while passing through the rectangular hole
5
a
of the slitted member
5
and the cylindrical lens
6
after being shaped into parallel beams in a horizontal main scanning direction and the vertical sub scanning direction while passing through the collimator lens
4
.
The beam converged into the vertical sub scanning direction as described above is reflected at the polygon mirror
7
rotating at a high speed such that it has a predetermined angle and then, is converged into the main scanning direction by the scanning lens
8
comprising the toric lens
8
a
and the focusing lens
8
b
, to be focused onto the photosensitive drum
9
thereby to realize a desired picture.
On the other hand, in the optical scanner, because, especially, the laser diode module is varied in assembling positions of respective lenses and conditions of focuses spotted onto the photosensitive drum
9
, assembling operations must be performed with a high precision.
FIGS. 3 and 4
illustrate a conventional laser diode module is an assembled state.
The laser diode
3
is positioned on a board
10
. A case
11
which is formed at its front part with an internally threaded portion
11
a
, is coupled to the board
10
.
A holder
12
which is formed at its front part with an inserting groove
12
a
of a predetermined depth, is screwed into the internally threaded portion
11
a
of the case
11
, and the collimator lens
4
is fitted into the inserting groove
12
a
of the older
12
by a fastener
13
.
The slitted member
5
which is formed with the rectangular hole
5
a
, is coupled to a front portion of the holder
12
.
At this time, a spring
14
is interposed between a front surface of the case
10
and a rear surface of the holder
12
. The spring
14
functions to elastically bias the holder
12
outward to prevent the holder
12
from shaking by outside shock, etc.
In the laser diode module constructed as mentioned above, an optical axial distance adjustment operation of the collimator leans
4
is implemented by moving the holder
12
into which the collimator lens
4
is embedded, forward and backward along the case
11
.
Further, as shown in FIGS.
3
(
a
) through
3
(
c
), an optical axis of the laser diode
3
is adjusted by moving the laser diode
3
which is fastened to the board
10
by fastening screws S leftward, rightward, upward and/or downward about the board
10
while screwing or unscrewing the fastening screws S.
However, the conventional laser diode module suffers from defects as described below.
First, since a multitude of components including the holder
12
into which the collimator lens
4
is embedded, the case
11
, fastener
13
for fastening the collimator lens
4
to the holder
12
, and the spring
14
, are needed, the number of components is increased, whereby manufacturing cost is increased and assembling workability is deteriorated.
Second, because a tool for separately adjusting the holder
12
is needed so as to move the holder
12
forward or backward within the case
11
, manufacturing cost is further increased.
Third, although the holder
12
is prevented to some extent from shaking by the spring
14
and the fastener
13
, if outside shock continuously acts on the holder
12
or elastic force of the spring
14
is changed after a predetermined period of time the holder
12
is caused to move or shake, whereby the optical axial distance between the collimator lens
4
and the laser diode
3
varies.
Fourth, in the process of threading a circumferential inner surface of the case
11
and circumferential outer surface of the holder
12
, a machining error maybe caused, whereby quality of end products cannot be uniformed.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a laser diode module of an optical scanner, which enables an optical axial distance adjustment operation between a collimator lens and a laser diode to be easily performed, reduces the number of components, thereby accomplishing cost reduction and improving workability, and allows quality of end products manufactured in large quantities to be uniform thereby elevating reliability.
In order to achieve the above object, according to one aspect of the present intention, there is provided a laser diode module of an optical scanner, comprising: a circuit board; a case fastened to a surface of the circuit board after being moved leftward, rightward, upward and/or downward, the case having a laser diode embedded therein; a slider fastened to a front surface of the case and having a barrel type guide surface which is formed at a center portion when viewed in an optical axial direction of a laser beam and extends in the optical axial direction and pair of flat guide surfaces which are formed at both side portions, respectively, and extend in the optical axial direction, the slider having a shape which is opened upward; a lens holder having a body and a pair of guide pieces, the body being seated on[to] the barrel type guide surface of the slider such that it can slide thereon forward and backward in the optical axial direction and being formed with an inserting hole, the pair of guide pieces being integrally coupled to both side surfaces of the body, respectively, and being seated on[to] the pair of flat guide surfaces of the slider, respectively; a collimator lens fitted into the inserting hole of the body of the lens holder for shaping laser beams emitted from the laser diode into parallel light beams; and a lens fastener fitted into the inserting hole of the body of the lens holder for preventing the collimator lens from shaking, thelens fastener being formed with a slit.
According to another aspect of the present invention, there is provided a laser diode module of an optical scanner, comprising: a circuit board; a case fastened to a surface of the circuit board after being moved leftward, rightward, upward and/or downward, the case having a laser diode embedded therein; a slider fastened to a front surface of the case and having a barrel type guide surface which is formed at a center portion when viewed in an optical axial direction of a laser beam and extends in the optical axial direction and a pair of flat guide surfaces which are formed at both side portions, respect
Darby & Darby
Samsung Electro-Mechanics Co., LTD
Tremblay Mark
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