Facsimile and static presentation processing – Facsimile – Picture signal generator
Reexamination Certificate
2000-12-20
2004-05-18
Coles, Edward (Department: 2622)
Facsimile and static presentation processing
Facsimile
Picture signal generator
C358S474000, C358S488000, C358S461000
Reexamination Certificate
active
06738165
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image reading apparatus, such as an image scanner, used for reading out images printed or drawn on an image-carrying medium.
2. Description of the Related Art
A conventional image reading apparatus is disclosed in JP-A-11(1999)-215301 for example. This apparatus, as shown in
FIG. 8
of the accompanying drawings of the present application, includes a housing
91
upon which a transparent plate
90
is mounted. The housing
91
is made by molding awhile synthetic resin material. Inside the housing
91
is formed a light passage
92
defined by first and second wall surfaces
92
a
,
92
b.
The conventional image reading apparatus also includes an insulating substrate upon which a plurality of light sources (light-emitting diodes)
93
are mounted. As shown in
FIG. 8
, light is emitted from the light sources
93
and may be reflected on the wall surfaces
92
a
,
92
b
. Thus, the light is led to the image reading section Se on the upper surface of the transparent plate
90
. Below the image reading section Se, the housing
91
supports a lens array
94
for focusing the reflected light from the image reading section Se onto a plurality of light-receiving elements
95
mounted on the insulating substrate. In accordance with the amount of received light, each of the elements
95
outputs image reading signals.
As stated above, the housing
91
of the conventional apparatus is produced by molding resin. Specifically, referring to
FIG. 9
of the accompanying drawings, use is made of two molding pieces, namely, an upper molding piece
96
and a lower molding piece
97
. The upper molding piece
97
is provided with a downward (first) projection
96
a
, while the lower molding piece
97
is provided with an upward (second) projection
97
a
. As seen from the figure, the first and the second projections
96
a
,
97
a
cooperate to form the light passage
92
of the housing
91
.
In this manner, however, it is impossible to cause the upper portion
92
a
of the first wall surface
92
a
to protrude to the right (see arrow N
1
) beyond the lower portion
92
b
′ of the second wall surface
92
b
. Thus, in the conventional apparatus, the uppermost width L
1
of the light passage
92
is made unduly large. Consequently, as shown in
FIG. 8
(see arrows n), part of the light emitted from the light sources
93
will go out of the light passage
92
without illuminating the image reading section Se.
This disadvantage can be overcome by using a light reflector
98
, as shown in
FIG. 10
of the accompanying drawings, which is prepared separately from the housing
91
(the light reflector
98
is also disclosed in above-mentioned JP-A-11-215301). The reflector
98
is provided with a light shielding portion
98
a
protruding to the right beyond the lower portion
92
b
′ of the second wall surface. Because of this structure, the light passage
92
has an uppermost width L
2
smaller than the width L
1
of FIG.
8
.
While having such an advantage, the second conventional apparatus of
FIG. 10
has the following shortcomings. First, the preparation of the reflector
98
, which needs to be produced separately from the housing
91
, may impair the production efficiency and increase the production cost. Second, additional positioning means is required for holding the reflector
98
in place within the housing
91
.
Further, the conventional apparatus of
FIG. 10
(and the apparatus of
FIG. 8
as well) is disadvantageous in the following respects. Specifically, in the apparatus of
FIG. 10
, the plurality of light sources
93
are spaced from each other in the longitudinal direction of the housing
91
. Part of the light emitted from each light source
93
indirectly reaches the image reading section Se after being reflected (scattered, to be precise) by the wall surfaces defining the light passage
92
, whereas the other part of the light directly reaches the section Se, traveling straight from the light source
93
to the section Se, as shown by the arrow n
1
in FIG.
10
. The indirect light from the light source
93
can uniformly illuminate the image reading section Se, since the indirect light, scattered by the wall surfaces, will be distributed uniformly over the length of the section Se. On the other hand, the direct light from the light sources
93
is not subjected to such scattering. Thus, as shown in
FIG. 11
, the direct light is liable to produce a non-uniform illuminating condition in which relatively bright portions BP and relatively dark portions DP are disposed alternately along the section Se. Clearly, such non-uniformity in brightness makes it difficult or even impossible to achieve accurate image reading operation.
Still further, in the conventional apparatus of
FIG. 10
(and the one of FIG.
8
), the lens array
94
is simply fitted into a lens holding groove formed in the housing
91
. Thus, the lens array
94
may be displaced in the groove or even come out of the groove. Also, the lens array
94
may be thermally warped in the vertical direction.
SUMMARY OF THE INVENTION
The present invention has been proposed under the circumstances described above, and its object is to overcome the problems encountered in the conventional image reading apparatus.
According to the present invention, there is provided an image reading apparatus includes a housing provided with a light passage, a transparent plate mounted on the housing, a light source for emitting light into the light passage, a lens array facing an image reading section on the transparent plate, a plurality of light-receiving elements arranged in an array extending in a primary scanning direction, and a light reflector formed on the transparent plate. The reflector is offset from the image reading section in a secondary scanning direction perpendicular to the primary scanning direction.
The light reflector may be a white material applied on the transparent plate or a white strip member fixed to the transparent plate.
According to a preferred embodiment of the present invention, the light reflector may cover the entire surface of the transparent plate except a predetermined region facing the lens array.
Preferably, the apparatus of the present invention may further include a light blocker for preventing light from traveling directly from the light source to the image reading section.
Preferably, the housing may be provided with a plurality of inner wall surfaces defining the light passage, wherein the light blocker may be located on a particular one of the inner wall surfaces.
In a preferred embodiment of the present invention, the light source may be offset from the image reading section in the secondary scanning direction. In this case, the particular one of the inner wall surfaces may be located between the light source and the image reading section, as viewed in the secondary scanning direction.
Preferably, the light blocker may reflect light instead of absorbing light.
Preferably, the light blocker may be formed integral with the housing.
Preferably, the housing may be formed with a lens array fixing slit and an adhesive supplying bore communicating with the slit. Adhesive supplied in the adhesive supplying bore serves to hold the lens array in place.
Preferably, the apparatus of the present invention may further include a light absorber arranged to enclose the light-receiving elements. The light absorber may be provided with a contact portion held in engagement with the lens array, wherein the contact portion corresponds in position to the adhesive supplying bore.
Preferably, the adhesive supplying bore may be unopened toward the image reading section. With such an arrangement, a light-reflecting surface can be provided near the image reading section, whereby light is effectively directed toward the image reading section.
According to a preferred embodiment of the present invention, the adhesive supplying bore may be open in a direction going from the image reading section to the light-receiving elements.
Preferably,
Bednarek Michael D.
Coles Edward
Gibbs Heather D
Rohm & Co., Ltd.
Shaw Pittman LLP
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