Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
1999-03-29
2001-01-30
Ball, Michael W. (Department: 1733)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S242000, C359S204200, C372S024000, C372S101000, C372S102000, C372S103000, C156S275700, C156S293000
Reexamination Certificate
active
06181363
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a light-source device of a multi-beam scanning apparatus.
2. Discussion of the Background
It is well known that in an image forming device, such as a printer or a digital copying machine, a scanning apparatus scans a photosensitive surface with light beams of a semiconductor laser for forming an image thereupon.
As an example of the above scanning apparatus, there is known a multi-beam scanning apparatus in which a plurality of light emitting devices are used. In the multi-beam scanning apparatus, a plurality of beams emitted by the plurality of light emitting devices are guided to a scanned surface via a common optical system, and converged in a sub-scanning direction as a plurality of mutually separated spots. The plurality of beams are simultaneously deflected by a deflector included in the optical system, and the scanned surface is scanned by the plurality of beams formed as the spots.
FIG. 4A
illustrates an example of a multi-beam scanning apparatus, in which two beams are simultaneously radiated from a light-source device
10
. These two beams form a parallel light flux, and are converged in a sub-scanning corresponding direction by a cylindrical lens
12
to form longitudinal linear images in a main scanning corresponding direction in the vicinity of a deflecting/reflecting surface of a rotating polygonal mirror
14
as a deflector. The sub-scanning directions is a direction corresponding to a sub-scanning direction on an optical path leading to a scanned surface from a light source, and the main scanning direction is a direction corresponding to a main scanning direction on the optical path to the scanned surface from the light source. Beams reflected in the deflecting/reflecting surface of the rotating polygonal mirror
14
are deflected at an equiangular velocity with uniform rotation of the rotating polygonal mirror
14
. The beams are then incident upon f&thgr; mirror
16
having an image forming function, reflected by the f&thgr; mirror
16
, and turned by a mirror
18
. Then, the beams are transmitted through a longitudinal toroidal lens
20
having a barrel-shaped toroidal surface, and have their optical paths folded by a mirror
22
. Next, the beams are converged in spots on a photosensitive surface of a photoconductor unit
24
as the scanned surface via the f&thgr; mirror
16
and longitudinal toroidal lens
20
. In this case, the f&thgr; mirror
16
mainly converges each deflected beam in the main scanning direction. Moreover, the longitudinal toroidal lens
20
cooperates with the f&thgr; mirror
16
to converge each beam in the sub-scanning direction.
In the light-source device
10
, as illustrated in
FIG. 4B
, beams radiated from two semiconductor lasers
101
,
102
are formed into a parallel light flux by coupling lenses
103
,
104
as collimator lenses supported by a holder
60
(see FIG.
5
), described later, and synthesized by a beam synthesizer
105
.
The beam synthesizer
105
is provided for combining optical axes of the parallel flux from the coupling lenses
103
,
104
, and the beam spots are overlapped with one another on the scanned surface by arranging the semiconductor lasers
101
,
102
on optical axes of the coupling lenses
103
,
104
.
As illustrated in
FIG. 4B
, the beam synthesizer
105
is integrally constructed by a ½ wavelength plate
1051
and a prism
1052
. The prism
1052
includes a polarizing/separating film
1053
. The polarizing/separating film
1053
transmits P polarized light, and reflects S polarized light.
The beam synthesizer
105
is supported by the holder
60
constructed as illustrated in
FIG. 5
, in which the holder
60
includes a plate base
61
and a shelf-like portion
62
.
The plate base
61
has screw through holes b
1
to b
4
(b
4
not shown) formed in four comers, and is fixed to a casing (not shown) via screws (not shown) passed through the screw through holes b
1
to b
4
.
The shelf-like portion
62
includes a member formed integral with the flat plate base
61
and a overhang piece and therefore has an angled side face. The member formed integral with the base plate
61
is formed with semiconductor laser attachment holes
63
,
64
leading to the plate base
61
.
As shown in
FIG. 5A
, a portion
621
for holding the coupling lenses
103
,
104
and a portion
622
for holding the beam synthesizer
105
are formed on a top surface of the overhang piece of the shelf-like portion
62
, which is parallel with the optical axes of the semiconductor lasers
101
,
102
pressed in the attachment holes
63
,
64
(refer to FIG.
5
B).
The coupling lenses
103
,
104
are made integral with the shelf-like portion
62
by an adhesive applied to bonding areas
6211
,
6212
of the holding portion
621
. Moreover, in
FIG. 5A
, numeral
6221
denotes an area for bonding the beam synthesizer
105
, and as illustrated in
FIG. 5B
, the beam synthesizer
105
is bonded and fixed in the bonding area
6221
.
The holder
60
is provided with a casing (not shown) attached and fastened via the screw through holes b
1
to b
4
. Also provided is a ¼ wavelength plate for circularly polarizing each synthesized beam and an aperture for shaping the synthesized beam which are arranged in the casing on an optical axis between the beam synthesizer
105
and the cylindrical lens
12
(FIG.
4
A).
In the light-source device
10
constructed as described above, when the semiconductor lasers
101
,
102
and the beam synthesizer
105
are assembled into the light-source device
10
, the semiconductor lasers
101
,
102
are first pressed into the attachment holes
63
,
64
. Then, the beam synthesizer
105
is fixed in the bonding area
6221
, after its optical axis position relative to the semiconductor lasers
101
,
102
is adjusted, by a photo-setting adhesive, e.g., an adhesive using a ultraviolet setting resin.
Subsequently, after a beam shaping aperture AP (
FIG. 5B
) is inserted and fixed into a retaining groove
623
(FIG.
5
A), the coupling lenses
103
,
104
are adjusted in position relative to the optical axes of the semiconductor lasers
101
,
102
in such a manner that two spots formed by the beams of the semiconductor lasers
101
,
102
are separated at a desired distance on the scanned surface. The coupling lenses
103
,
104
are then fixed in the bonding areas
6211
,
6212
by the adhesive using the ultraviolet setting resin.
The light-source device
10
is rotatable centering on the optical axes of the coupling lenses
103
,
104
. By rotating the light-source device
10
, the separated amount of the spots on the scanned surface can be adjusted in the sub-scanning direction to change a density of the spots, i.e., a writing density, on the scanned surface. For this purpose, as shown in
FIG. 4A
, an angle controller
26
is provided to which a writing density switch signal is transmitted. In addition, the entire light-source device
10
can be rotated to obtain a desired writing density by operating a motor
28
in response to the signal.
In
FIG. 4B
, a writing signal for changing the writing density is transmitted to a semiconductor laser drive section
32
(illustrated as LD drive section in the drawing) via a writing controller
30
. The semiconductor laser drive section
32
modulates and controls light of the semiconductor laser
101
in response to an odd line writing signal, and modulates and controls light of the semiconductor laser
102
in response to an even line writing signal. The construction of the light-source device
10
is described in detail in Japanese Patent Application No. 256352/1997 filed by the present applicant.
In the above light-source device
10
, a center of the attachment holes
63
,
64
of the semiconductor lasers
101
,
102
and a center of the bonding portions of the coupling lens
103
,
104
are positioned on a straight line. On the other hand, for changing the writing density on the scanned surface by separating the beams in the main scanning direction and sub-sc
Ball Michael W.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
Tolin Michael A
LandOfFree
Light-source device of a multi-beam scanning apparatus 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-source device of a multi-beam scanning apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Light-source device of a multi-beam scanning apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2436988