Photocopying – Projection printing and copying cameras – Illumination systems or details
Reexamination Certificate
1998-12-01
2001-09-04
Adams, Russell (Department: 2851)
Photocopying
Projection printing and copying cameras
Illumination systems or details
C399S118000, C358S474000
Reexamination Certificate
active
06285441
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image sensor unit and an image reader capable of reading image information, such as an image scanner, a facsimile, or a copying machine.
2. Description of the Related Art
Hitherto, various types of devices capable of reading an image, such as an image scanner, a facsimile, and a copying machine, have been proposed. There is, for example, one type having a relatively simple structure. In the structure, an image sensor unit, which can detect an image occupying up to the entire width of an original, is disposed parallel to an original-holding glass member. The image sensor unit is moved by an amount equal to the length of the original in order to scan the entire surface of the original. Various types of image sensor units have also been, hitherto, proposed. In one main type of image sensor unit, the original is illuminated by an illuminating member with a size equal to the width of the original. The light, reflected from the original, is guided to an image-focusing lens by a mirror in order to focus an image, which is reduced in size, on a line sensor, such as a charge-coupled device (CCD). In another main type of image sensor unit, the original is similarly illuminated by a light-emitting diode (LED) or the like. The light, reflected from the original is focused, with a magnification of 1
x,
on a light-receiving surface of the line sensor with a length equal to the width of the original, by a selfoc lens.
A description will now be given of a conventional image reader and an image sensor unit thereof, with reference to
FIGS. 16
to
19
.
FIG. 16
is a front view of the conventional image reader.
FIG. 17
illustrates the conventional image reader, as viewed from above the conventional image reader.
FIG. 18
is an enlarged front view of the main portion of the conventional image reader.
FIG. 19
illustrates the image sensor unit of the conventional image reader.
In the image reader, an original-holding glass member
101
, for placing thereon an original, is disposed at the top portion of the body of the image reader. A line sensor unit
102
, serving as an image sensor unit for reading the image on the original, is disposed below the original-holding glass member
101
. The line sensor unit
102
comprises component parts that are integrally formed together into a unit. They are a light-emitting diode (LED) for illuminating an original; a selfoc lens array for focusing an image light reflected from the original illuminated by the light-emitting diode; and an optical sensor element for converting the image focused by the selfoc lens array into electrical signals. The line sensor unit
102
is secured to a sensor-holding frame
103
with screws, after positioning the line sensor unit
102
and the sensor-holding frame
103
by fitting pins
102
a
and
102
b,
at the bottom surface of a housing of the line sensor unit
102
, into respective holes in the sensor-holding frame
103
. The sensor-holding frame
103
is rotatably held by a moving holding frame
104
, after fitting holes
104
a
and
104
b,
disposed at both ends of the moving holding frame
104
, onto rotational shaft portions
103
a
and
103
b,
disposed at both ends of the sensor-holding frame
103
in a longitudinal direction thereof. The positioning of the sensor-holding frame
103
and the moving holding frame
104
, in the longitudinal direction of the line sensor unit
102
, is achieved by fitting a protrusion
103
c
of the sensor-holding frame
103
to a groove
104
c
in the moving holding frame
104
. The moving holding frame
104
is guided by a guide bar
106
affixed to a body base
105
. Coil springs
107
a
and
107
b
are provided at the sensor-holding frame
104
, and bias the sensor-holding frame
103
towards the original-holding glass member
101
. Two sliding protrusions
120
a
and
120
b
are affixed to the sensor-holding frame
103
. The distance between the line sensor unit
102
and the original-holding glass member
101
is maintained by the sliding protrusions
120
a
and
120
b
that are in contact with the original-holding glass member
101
. Such a structure, in which sliding protrusions are in contact with an original-holding glass member, is particularly suitable for use in small image sensor units with a small depth of field, and allows the distance between the original-holding glass member and the protrusions to be maintained with a relatively high precision. The driving of the moving holding frame
104
is achieved by causing a motor
109
, an idler gear
121
, and an idler gear
122
to drive a belt
112
and a pair of pulleys
110
and
111
, and by linking one portion of the belt
112
to the moving holding frame
104
. The belt
112
and the pair of pulleys
110
and
11
are provided at the body of the image reader in the direction of movement of the moving holding frame
104
. The motor
109
is affixed to the body of the image reader.
The above-described conventional image sensor unit is a substantially rectangular parallelepipedic unit. In order to form the above-described high-precision supporting structure for the image sensor unit
102
, the image sensor unit
102
is temporarily secured to the sensor-holding frame
103
; a rotary mechanism is provided between the sensor holding frame
103
and the moving holding frame
104
; a sliding protrusion is formed on the sensor holding frame
103
; and a member, for positioning the image sensor unit
102
in the longitudinal direction thereof, is provided between the sensor-holding frame
103
and the moving holding frame
104
. Therefore, when such a conventional image sensor unit is used in an image reader, a large space must be provided around the image sensor unit, thereby increasing the size of the image reader. In addition, a sensor-holding member is required, thereby increasing costs. Further, since part tolerances accumulate during incorporation of the image sensor unit into the image reader, the precision of the image reader is reduced accordingly.
SUMMARY OF THE INVENTION
In view of the above-described problems, it is an object of the present invention to provide a small image reader.
It is another object of the present invention to provide an image reader capable of performing reading operations with high precision.
It is still another object of the present invention to provide an image sensor unit comprising a light source for illuminating an original; a reading element for reading an image on the original; and a housing for supporting the light source and the reading element, the housing having a shaft or a bearing for allowing rotation of the housing, the shaft or the bearing being disposed so as to be parallel to the reading element.
It is still another object of the present invention to provide an image reader comprising an original-holding plate; an image sensor unit including a light source for illuminating an original, a reading element for reading an image on the original, and a housing with either a shaft or a bearing for allowing rotation of the image sensor unit; and a holding member for holding the image sensor unit, the holding member having either a bearing or a shaft for engaging the shaft or the bearing of the image sensor unit.
Further objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.
REFERENCES:
patent: 5579129 (1996-11-01), Iwata et al.
patent: 5764382 (1998-06-01), Shiraishi
patent: 5825513 (1998-10-01), Hasegawa
patent: 5966221 (1999-10-01), Tellam et al.
patent: 6005685 (1999-12-01), Tsai
Adams Russell
Brown Khaled
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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