JPH10308852A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an image reader thin in height direction by providing a 1st traveling body with at least two mirrors. SOLUTION: When reading image information on an original, for example, an original 12 is irradiated with light from a light source of fluorescent lamp and its reflected light is guided into a 1st mirror 13a on a 1st traveling body 13. Afterwards, this reflected light is guided through 2nd and 3rd mirrors 13b and 13c on the 1st traveling body 13 into a 1st mirror 14a on a 2nd traveling body 14. Further, light reflected on the 1st mirror 14a on the 2nd traveling body 14 is reflected on a 2nd mirror 14b and guided through a reduced image formation lens 15 into a line sensor 16. In this case, the 1st mirror 14a on the 2nd traveling body 14 is arranged at 45 deg. to the surface of original, and the 2nd mirror 14b is arranged at 90 deg. to the 1st mirror 14a. Then, the 1st traveling body 13 moves in a subscanning direction at a velocity V and the 2nd traveling body 14 moves in a subscanning direction a velocity v/2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus, and more particularly to an optical system of a thin original reading apparatus suitable for a scanner, a copying machine, a facsimile, and the like.

[0002]

2. Description of the Related Art As an optical system used in an image reading apparatus such as a scanner, a copying machine, a facsimile, etc., a document is irradiated with light from an illumination system and reflected light from the document is reduced to a line sensor by an image forming lens. There is a so-called reduced reading optical system that forms an image. Although there has been a demand for miniaturization of such an image reading apparatus, particularly, with the spread of personal computers and the like, the frequency of using the scanner alone without being incorporated in a copying machine or the like has increased, and Demands for miniaturization and thinning are increasing. FIG. 4 is a view showing the configuration of a conventional original stationary image reading apparatus using a reduced reading optical system, wherein 1 is a contact glass, 2 is an original, 3 is a first traveling body including a first mirror 3a, 4 Is the first mirror 4
a, a second traveling body including the second mirror 4b, 5 is a reduction imaging lens, and 6 is a line sensor. When reading image information of the document 2 set on the contact glass 1, light from a light source (not shown), for example, a fluorescent lamp, is applied to the document 2, and the reflected light is introduced to the first mirror 3a. . Thereafter, the light is reflected by each of the mirrors 4 a and 4 b of the second traveling body 4 and passes through the reduction imaging lens 5 to the line sensor 6.
Will be introduced. The line sensor 6 is provided with a plurality of photoelectric conversion elements such as a CCD in parallel, and converts light from a document surface imaged on the photoelectric conversion elements by the reduction imaging lens 5 into an electric signal for each line. . The first
The traveling body 3 and the second traveling body 4 are mounted on different carriages respectively, and when reading the longitudinal direction of the document 2,
The first traveling body moves at a speed V to a position 3 'in the direction of the arrow, and the second traveling body 4 moves at a speed V / 2 to a position 4' in the direction of the arrow. Thus, the first carriage
The traveling body 3 and the second traveling body 4 are mounted to guide the reflection from the document surface to the reduction imaging lens 5 with a constant optical path length regardless of the movement of the reading position by the sub-scanning.

[0003]

However, in the case of the above-described reduced reading optical system, the light source must be disposed between the first mirror 3a of the first traveling body 3 and the contact glass 1, so that the first traveling optical system is required. The distance between the first mirror 3a of the body 3 and the contact glass 1 cannot be reduced, and in order to realize high-speed reading of an image, it is necessary to make a sufficient amount of light incident on the reduction imaging lens 5. For this purpose, it is necessary to ensure a sufficient width (width in the thickness direction of the reading optical system) of each mirror, especially the second mirror 3B of the second traveling body 4 close to the reduction imaging lens 5 on the optical path. Yes,
There is a problem that the thickness of the document reading device cannot be reduced. As a conventional technique for miniaturizing an optical system, there is an invention disclosed in Japanese Patent Application Laid-Open No. 2-48625. However, the technique disclosed thereby discloses a technique in which a plurality of reflecting mirrors are provided in an optical path of a reading optical system. The length of the optical system in the length direction is reduced by the multiple reflection optical system in which the optical system is disposed, and the thickness of the optical system in the height direction cannot be reduced. The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a reading optical system capable of achieving a significant reduction in the height of an image reading apparatus.

[0004]

According to a first aspect of the present invention, there is provided an image reading apparatus, comprising: an illumination system for illuminating an original; and a light beam emitted by the illumination system. Is maintained at a constant distance from the document surface, and scans at a constant speed V in the sub-scanning direction. A first mirror arranged at an angle of ゜, and 90
A second traveling body having a second mirror disposed at an angle of ゜, an imaging lens for reducing and imaging reflected light of the original via the second traveling body, and an original image formed by the imaging lens In the image reading optical system including a line sensor that photoelectrically converts the data, the first traveling body has at least two or more mirrors. The invention according to claim 2 of the image reading device according to the present invention is the image reading device according to claim 1, wherein the reflected light reflected by the first mirror of the first traveling body is:
Light reflected from the first traveling body in a direction opposite to the traveling direction of the second traveling body and emitted from the mirror of the first traveling body to the first mirror of the second traveling body is parallel to the document surface. The mirror of the first traveling body is arranged as described above. An image reading apparatus according to a third aspect of the present invention is the image reading apparatus according to the first or second aspect, wherein the angle θ of the first mirror of the first traveling body with respect to the original surface is in a range of θ ≦ 45 °. It is characterized by satisfaction. The invention according to claim 4 of the image reading apparatus according to the present invention is characterized in that, in the image reading apparatus according to any one of claims 1 to 3, the mirror of the first traveling body includes two mirrors. The invention according to claim 5 of the image reading apparatus according to the present invention is characterized in that in the image reading apparatus according to claims 1 to 4, the line sensor is a three-line sensor.

[0005]

According to the first aspect of the present invention, the optical axis of the light beam incident on the second traveling body can move to the contact glass, and the first traveling body and the second traveling body can be moved. The height of the image reading device can be reduced even if the width of each mirror included in the image reading device is increased, and a small and high-speed image reading device can be realized. According to the second aspect of the present invention, in addition to the first aspect, the first traveling direction is such that the optical axis of the light emitted from the first mirror of the first traveling body is opposite to the arrangement direction of the second traveling body. Since the first mirror of the body is disposed, the space in the image reading device can be effectively used, and not only the thickness can be reduced but also the size can be reduced. According to the third aspect of the present invention, in addition to the first or second aspect, the optical system can be made thinner by arranging the angle of the first mirror of the first traveling body within a predetermined range. . According to the fourth aspect of the invention, in addition to the first to third aspects,
By setting the number of mirrors included in the first traveling body to two, a small and thin image reading apparatus can be configured at low cost.
According to the fourth aspect of the present invention, in addition to the first to fourth aspects, by using an optical system using a three-line CCD, a small and thin full-color image reading apparatus can be configured at low cost. Becomes

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a diagram showing a configuration of an image reading apparatus according to the present invention.
1 is a contact glass, 12 is a document, 13 is a first traveling body including a first mirror 13a, a second mirror 13b, and a third mirror 13c, 14 is a first mirror 14a, a second mirror 14b
, 15 is a reduction imaging lens, and 16 is a line sensor. When reading the image information of the document set on the contact glass 1, the image reading device configured as described above, for example, a light source of a fluorescent lamp (not shown)
Irradiates the original 12 with light from the first traveling body 1
3 is introduced to the first mirror 13a. Thereafter, the light is introduced into the first mirror 14a of the second traveling body 14 via the second mirror 13b and the third mirror 13c of the first traveling body 3. Further, the light reflected by the first mirror 14a of the second traveling body 14 is reflected by the second mirror 14b, and is introduced into the line sensor 16 via the reduction imaging lens 15. Line sensor 16
For example, a plurality of photoelectric conversion elements such as a CCD are provided in parallel, and light from a document surface imaged on the photoelectric conversion elements by the reduction imaging lens 15 is converted into an electric signal for each line. The first mirror 14a of the second traveling body 14 is arranged at an angle of 45 ° with respect to the document surface, and the second mirror 14b is arranged at an angle of 90 ° with respect to the first mirror 14a. Also in this embodiment, the first traveling body 13 and the second traveling body 14 are mounted on different carriages, and when reading the longitudinal direction of the document 12,
The first traveling body keeps a fixed distance from the document surface and at a constant speed V to the position of the broken line 13 'in the sub-scanning direction (the direction of the arrow).
And the second traveling body 14 moves in the sub-scanning direction (the direction of the arrow) with respect to the first traveling body 13 at a speed V / 2 to a position indicated by a broken line 14 ', so that the reading position by the sub-scanning Irrespective of the movement of the original, the reflection from the document surface is guided to the reduction imaging lens 15 with a constant optical path length.

The difference between the image reading device of this embodiment and the image reading device described in the section of the prior art is that the first traveling body 1
3, the second mirror 13b and the third mirror 13b are provided even if the distance between the first mirror 13a of the first traveling body 13 and the contact glass 11 is the same as that of the conventional image reading apparatus. Using the mirror 13c and the second traveling body 14,
Since the optical axis of the light incident on the first mirror 14a of the second traveling body 14 is turned back in a state of being close to the contact glass 11, the first mirror 14a of the second traveling body 14 is
1, that is, the second traveling body 14 can be arranged close to the contact glass 11, so that the thickness of the image reading device can be significantly reduced in the height direction. In addition, since the second traveling body 14 can be arranged close to the contact glass 11, even if the width of the second mirror 14b of the second traveling body 14 is set to be large, the height of the image reading apparatus can be reduced. When high-speed reading is realized, the amount of light introduced into the reduction imaging lens 15 can be secured.

Further, in the optical system of a general image reading apparatus, the reading optical system is reduced in size by arranging the first traveling body 13 and the second traveling body 14 as close as possible. However, there are few components in the traveling direction (the right side in the figure) of the first traveling body 13 and the space is vacant. Therefore, in the image reading apparatus according to the present invention, the direction of the light reflected by the first mirror 13a of the first traveling body 13 is set to the opposite side (the right side in the drawing) to the second traveling body 14, and the space is vacant. A second mirror 13b and a third mirror 13c are arranged on the right side of the first mirror 13a in the drawing, and the second traveling body is arranged so that the reflected light emitted from the first mirror 13a is finally parallel to the surface of the contact glass 11. Since the light is emitted to the light source 14, the space that has not been conventionally used is utilized, and the size of the image reading device is reduced in spite of the fact that the number of reflecting mirrors used is increased as compared with the conventional image reading device. And a reduction in thickness can be realized. Further, since the reflected light from the final mirror (the third mirror 13c in this embodiment) of the first traveling body 13 is parallel to the surface of the contact glass 11,
The emitted light from the first traveling body 13 always enters a fixed position of the first mirror of the second traveling body 14, and the entire original can be read.

FIG. 2 is a view showing another embodiment of the image reading apparatus according to the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and their description is omitted. The difference between this embodiment and the above-described embodiment is the number of reflection mirrors arranged on the first traveling body 13. In the above-described embodiment, three reflection mirrors 13 are provided.
With the use of a to 13c, the optical axis was deflected by about 90 ° at each mirror, and the reflected light from the document was made incident on the second traveling body 14 with the optical axis deflected by a total of 270 °. In the embodiment, only the first mirror 13a and the second mirror 13b are used, and the optical axis is deflected by about 135 ° by each mirror so that the reflected light from the document is incident on the second traveling body 14. Even if the first traveling body 13 is configured with such a small number of mirrors, the second traveling body 14 can be arranged close to the contact glass 11 similarly to the above-described embodiment, and the image reading apparatus can be made thin. Can be achieved, and cost reduction can be realized.

FIGS. 3A and 3B are enlarged views of the first traveling body in the first embodiment and the second embodiment, respectively. In order to make the optical system of the image reading apparatus thin, the installation angle θ of the first mirror 13a (the angle of the first mirror 13a of the first traveling body 13 with respect to the original surface) on which the reflected light from the original surface is incident is required. It must be at least 45 ° or less. That is, when θ exceeds 45 °, the first mirror 1
The direction of deflection of the reflected light emitted from 3a is 9
The angle is smaller than 0 °, and the reflected light from the first mirror 13a is emitted farther (lower side in the figure) as viewed from the contact glass 11, so that the effect of reducing the thickness is reduced. Therefore, in order to reduce the thickness of the document reading apparatus, the installation angle θ must be θ ≦ 4.
Preferably, 5 ° is satisfied. In the above description, the configuration of the line sensor 16 is not particularly mentioned. However, even if the line sensor 16 has one line, or R (red) and G (green) are used as photoelectric conversion elements constituting the line sensor. ), CC with three lines of B (blue)
The image reading apparatus according to the present invention may be applied to a color image reading apparatus by configuring the image reading apparatus according to the present invention.

[0011]

As described above, according to the first aspect of the invention, since the optical axis of the light beam incident on the second traveling body can move to the contact glass, the first traveling body and the second traveling body can be moved. The height of the image reading device can be reduced even if the width of each mirror included in the image reading device is increased, and a small and high-speed image reading device can be realized. According to the second aspect of the invention, in addition to the effects obtained by the first aspect, the optical axis of the light emitted from the first mirror of the first traveling body is opposite to the direction in which the second traveling body is disposed. Since the first mirror of the first traveling body is arranged in the image reading device, the space in the image reading device can be effectively utilized, and not only a reduction in thickness but also a reduction in size can be achieved. According to the third aspect of the invention, in addition to the effects obtained by the first aspect of the invention, the thickness of the optical system can be reduced by arranging the angle of the first mirror of the first traveling body within a predetermined range. it can. In the invention according to claim 4,
In addition to the effects obtained by the first aspect of the present invention, by setting the number of mirrors included in the first traveling body to two, it is possible to configure a small and thin image reading apparatus at low cost. According to the fifth aspect of the present invention, in addition to the effects obtained by the first aspect of the present invention, a small and thin full-color image reading apparatus can be configured at low cost by using an optical system using a three-line CCD. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an image reading apparatus according to the present invention.

FIG. 2 is a diagram showing another example of the image reading apparatus according to the present invention.

3A is an enlarged view of a first traveling body in a first embodiment, and FIG. 3B is an enlarged view of a first traveling body in a second embodiment.

FIG. 4 is a diagram illustrating a configuration of a document original image reading apparatus using a conventional reduced reading optical system.

[Explanation of symbols]

11 ... contact glass, 12 ... original, 13 ...
・ First traveling body, 13a ... First mirror, 13b ...
Second mirror, 13c: third mirror, 14: second
Running body, 14a: first mirror, 14b: second mirror, 15: reduction imaging lens, 16: line sensor

Claims (5)

[Claims] An illumination system for illuminating a document, a first traveling body that scans a light beam emitted from the illumination system at a constant distance from a document surface and at a constant speed V in a sub-scanning direction; 1
A scanning is performed at a speed of V / 2 with respect to the traveling body, and a first mirror arranged at an angle of 45 ° with respect to the document surface and a second mirror arranged at an angle of 90 ° with respect to the first mirror are arranged. An image reading optical system comprising: a second traveling body having an imaging lens for reducing and forming reflected light of the original via the second traveling body; and a line sensor for photoelectrically converting the original image formed by the imaging lens. An image reading apparatus, wherein the first traveling body has at least two or more mirrors. 2. The image reading apparatus according to claim 1, wherein
The reflected light reflected by the first mirror of the first traveling body is the first light.
The mirror of the first traveling body is arranged such that light reflected from the traveling body in a direction opposite to that of the second traveling body and emitted from the first traveling body to the second traveling body is parallel to the document surface. Image reading device. 3. An image reading apparatus according to claim 1, wherein an angle θ of the first mirror of the first traveling body with respect to the original surface is set.
Satisfies the range of θ ≦ 45 °. 4. The image reading apparatus according to claim 1, wherein the first traveling body has two mirrors. 5. The image reading apparatus according to claim 1, wherein said line sensor is a three-line sensor.