JP2001174932A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image reader capable of being miniaturized as a whole by arranging a power source device and an image processing circuit or the like on the bottom part of an image reader body. SOLUTION: A scanning optical system unit including a light source means for illuminating an original placed on an original platen, a plurality of mirrors reflecting luminous flux from the original illuminated by the light source means, an image forming lens forming the luminous flux reflected by the plurality of mirrors into a image and a reading means arranged at the image forming position by the image forming lens is moved relatively to the original, whereby the image information of the original is read. In such a case, the plurality of mirrors have one or more multiple reflection mirrors reflecting the luminous flux from the original plural times. As for one or more multiple reflection mirrors, the longest distance in the vertical direction to the original platen from the reflection surface thereof is shorter than the distance in the vertical direction to the original platen from the optical axis of the image forming lens, and as for the mirror by which the luminous flux from the original is reflected first out of the plurality of mirrors, the longest distance in the vertical direction to the original platen from the reflection surface thereof is shorter than the distance in the vertical direction to the original platen from the optical axis of the image forming lens.

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 image reading apparatus using a scanning optical system unit including a light source, a plurality of mirrors, an image forming lens, and reading means (a charge-coupled device such as a line sensor). The present invention relates to an image reading apparatus suitable for reading image information, such as an image scanner or a digital copying machine.

[0002]

2. Description of the Related Art Conventionally, various image reading apparatuses such as an image scanner and a digital copying machine have been proposed.

FIG. 6 is a schematic view of a main part of an image reading apparatus having a scanning optical system unit. A scanning optical system unit 607 in FIG. 9 includes a light source 603 and a plurality of scanning mirrors 60.
4a to 605d, an imaging lens 606, and a line sensor (or an image sensor or the like) as a reading element
The original is scanned without changing the relative positional relationship between the elements, such as 605.

[0006] A scanning optical system unit (hereinafter also referred to as a “carriage”) 607 in FIG. 1 includes a document 601 illuminated by a light source 603 that illuminates a document 601 placed on a document table glass (document table) 602. A line sensor 605 for reading a light beam, and a plurality of scanning mirrors 604 for guiding the light beam from the original 601 to the line sensor 605
a to 605d, and an image forming lens 606 for forming a light beam based on image information from the original 601 on the surface of the line sensor 605. This carriage 6
07 is sub-scanned in the direction of arrow A shown in FIG.

In FIG. 1, a plurality of scanning mirrors are first mirrors.
Mirror 604a, second mirror 604b, third mirror 60
4c, and a fourth mirror 604d.
From the first mirror 604a to the second mirror 604
b, from the second mirror 604b to the third mirror 604c,
The light enters the fourth mirror 604d from the third mirror 604c,
After that, each mirror passes between the first mirror 604a and the second mirror 604b and between the document table 602 and the first mirror 604a, enters the imaging lens 606, and forms an image on the line sensor 605 surface. Is arranged.

In such a configuration, the line sensor 6
Image information of the original read at 05 is sent to a predetermined image processing unit (not shown) as an electric signal, and is output after being subjected to predetermined signal processing. In addition, it has a power supply unit (not shown) for driving the present apparatus.

By the way, in this type of apparatus, there has been a demand for downsizing of the carriage, particularly. In order to reduce the size of the carriage, mainly the following two methods are widely known.

A method of widening the angle of the imaging lens and shortening the optical path length from the original to the line sensor is a method of increasing the number of mirrors and reducing the size of the entire carriage.

However, when the angle of the imaging lens is increased, the amount of peripheral light is reduced in proportion to the cos4 power law of the angle of view of the imaging lens, so that a stronger illumination light source is required. Also, since the aberration of the imaging lens increases,
There is also a problem that the line sensor cannot read an image accurately corresponding to a document image.

On the other hand, the method of increasing the optical path length by increasing the number of mirrors has a problem that mounting accuracy and assemblability deteriorate.

In order to solve such a problem, an image reading apparatus which secures an optical path length with a small number of mirrors has been proposed, for example, in Japanese Patent No. 2684363.
This publication discloses that a light beam from a document is reflected a plurality of times by one mirror.

FIG. 7 is a schematic view of a main part when the image reading device proposed in the publication is applied to an image scanner. In this figure, the same elements as those shown in FIG. 6 are denoted by the same reference numerals.

In FIG. 1, a plurality of scanning mirrors are first mirrors.
The mirror 704 includes a mirror 704a, a second mirror 704b, and a third mirror 704c. The light beam from the document 601 is transmitted from the first mirror 704a to the second mirror 704b.
4b to the third mirror 704c, from the third mirror 704c to the second mirror 704b again, and then pass between the first mirror 704a and the third mirror 704c to enter the imaging lens 606, which serves as a reading element. The mirrors are arranged so as to form an image on the surface of a line sensor (CCD) 605. In the figure, a long optical path length is secured by reflecting twice with the second mirror 704b.

As described above, although the number of mirrors for scanning is as small as three in FIG. 1, the mirror has the same optical path length as when four mirrors are used. To some extent.

[0015]

In recent years, this type of image reading apparatus has been required to be further reduced in size.
Particularly, since the image processing unit and the power supply unit are arranged at the bottom of the image reading apparatus as shown in FIG. In FIG. 8, the same elements as those shown in FIG. 7 are denoted by the same reference numerals.

However, the mirror 704b that reflects a plurality of times (hereinafter, also referred to as a "multi-reflection mirror") becomes large in both the longitudinal direction and the lateral direction, so that the arrangement of each optical element becomes difficult, and the entire carriage However, it was not always possible to reduce the size.

According to the present invention, in an image reading apparatus having a scanning optical system unit (carriage), at least one of a plurality of mirrors constituting one element of the scanning optical system unit is constituted by a multiple reflection mirror. By appropriately setting the arrangement of each element including the plurality of mirrors, it is possible to provide an image reading apparatus capable of reducing the size of the bottom of the scanning optical system unit and reducing the size of the entire apparatus. And

[0018]

According to a first aspect of the present invention, there is provided an image reading apparatus comprising: a light source for illuminating a document placed on a document table; and a plurality of light sources for reflecting a light beam from the document illuminated by the light source. A scanning optical system unit including a mirror, an imaging lens that forms an image of the light beams reflected by the plurality of mirrors, and reading means disposed at an imaging position of the imaging lens. The plurality of mirrors include at least one multi-reflection mirror for reflecting a light beam from the document a plurality of times; The mirror has a vertically longest distance from the reflecting surface to the platen, which is shorter than a vertical distance from the optical axis of the imaging lens to the platen,
The longest vertical distance from the reflecting surface of the mirror from which the light flux from the document first reflects out of the plurality of mirrors to the document table is a vertical distance from the optical axis of the imaging lens to the document table. It is characterized by being shorter than the distance.

According to a second aspect of the present invention, in the first aspect of the present invention, there are provided two multi-reflection mirrors for reflecting the light beam from the document a plurality of times, and the two multi-reflection mirrors have reflection surfaces substantially mutually. It is characterized by being arranged so as to be parallel.

According to a third aspect of the present invention, in the first aspect of the present invention, the plurality of mirrors include three mirrors of a first, a second, and a third mirror, and a light beam from the document is reflected by the first mirror. After that, the light is incident on the second mirror, the light reflected by the second mirror is incident again on the first mirror, the light reflected by the first mirror is incident again on the second mirror, and The mirrors are arranged such that the light beam reflected by the two mirrors enters the third mirror, and the light beam reflected by the third mirror enters the imaging lens.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the plurality of mirrors comprise four mirrors of first, second, third, and fourth mirrors, and a light beam from the document is transmitted to the first mirror.
After being reflected by the mirror, it is incident on the second mirror,
The light beam reflected by the mirror enters the third mirror,
The light beam reflected by the mirror again enters the second mirror, and the light beam reflected by the second mirror enters the fourth mirror,
The mirrors are arranged such that the light beam reflected by the fourth mirror is incident on the imaging lens.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the plurality of mirrors comprise three mirrors, a first mirror, a second mirror, and a third mirror, and a light beam from the document is reflected by the first mirror. After that, the light is incident on the second mirror, the light reflected by the second mirror is incident again on the first mirror, the light reflected by the first mirror is incident again on the second mirror, and The light beam reflected by the two mirrors enters the first mirror again,
The light beam reflected by the first mirror is incident again on the second mirror, the light beam reflected by the second mirror is incident on the third mirror, and the light beam reflected by the third mirror is incident on the imaging lens. Each mirror is arranged so as to be incident on the mirror.

According to a sixth aspect of the present invention, in the first aspect, the plurality of mirrors are first, second, third, fourth, and fifth mirrors.
The mirror comprises five mirrors, and a light beam from the document is reflected by the first mirror and then enters the second mirror;
The light beam reflected by the second mirror crosses the optical path between the document and the first mirror, passes through the optical path, and then enters the third mirror,
The luminous flux reflected by the third mirror passes through the optical path between the original and the first mirror, and then reenters the second mirror, where the luminous flux reflected by the second mirror is reflected by the original. After passing through the optical path between the first mirror and the first mirror, the light again enters the third mirror, and the light beam reflected by the third mirror crosses the optical path between the original and the first mirror. After passing through the fourth mirror, the light beam reflected by the fourth mirror crosses the optical path between the second mirror and the third mirror, passes through the optical path, and then enters the fifth mirror. The mirrors are arranged such that the light beam reflected by the fifth mirror is incident on the imaging lens.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG. 1 is a schematic view of a main part of Embodiment 1 when an image reading apparatus of the present invention is applied to an apparatus such as an image scanner, and FIG. 2 is shown in FIG. It is a principal part perspective view of an image reading device.

In FIG. 1, reference numeral 1 denotes an image reading apparatus main body; 102, an original platen glass (original platen);
01 is placed.

Reference numeral 107 denotes a scanning optical system unit, which includes a light source means 103 described later and a plurality of scanning mirrors 104a to 104a.
The document 10 includes an image forming lens 104c, an image forming lens 106, a reading unit 105, and the like.
1 is being read. The carriage 107
And the document 101 may be relatively moved to read the image information of the document 101. The scanning optical system unit 107 is hereinafter also referred to as a “carriage”.

Numeral 103 denotes light source means, which comprises, for example, a fluorescent lamp or a halogen lamp. 104a, 104
Reference numerals b and 104c denote first, second, and third mirrors, respectively, which are arranged at positions to be described later, and turn back a light beam from the document 101. Reference numeral 106 denotes an imaging lens which forms a light beam based on image information of the document 101 on the surface of the reading unit 105. Reference numeral 105 denotes a charge-coupled device such as a line sensor or an image sensor as a reading unit. 1
Reference numeral 08 denotes a sub-scanning motor as a driving device, which moves the carriage 107 in the sub-scanning direction.

In this embodiment, the plurality of scanning mirrors are first, second, and third mirrors 104a, 104b, and 104.
c, and after the light beam from the document 101 is reflected by the first mirror 104a,
4b, the light beam reflected by the second mirror 104b again enters the first mirror 104a,
The light beam reflected by 4a again enters the second mirror 104b, the light beam reflected by the second mirror 104b enters the third mirror 104c, and the light beam reflected by the third mirror 104c forms an imaging lens. Each mirror is arranged so as to be incident on the mirror 106.

In this embodiment, of the first, second and third mirrors 104a, 104b and 104c,
The second mirrors 104a and 104 are multiple reflection mirrors for reflecting a light beam from the document 101 a plurality of times, and the first and second mirrors 104a and 104b are the longest in the vertical direction from the reflection surfaces to the document table 102. The distances L ₁ and L ₂ are shorter than the vertical distance L ₃ from the optical axis of the imaging lens 106 to the document table 102, respectively, and the first mirror 104a that reflects the light flux from the document 101 first is used. longest distance L ₂ in the vertical direction to the platen 102 from the reflective surface are arranged each element to be shorter than the vertical distance L ₃ from the optical axis of said imaging lens 106 to the platen 102.

In this embodiment, the first and second mirrors 104a and 104b are arranged such that the reflection surfaces of the first and second mirrors 104a and 104b are substantially parallel to each other.

In the present embodiment, the light beam emitted from the light source 103 illuminates the lower surface of the original 101 and the original 10
A portion of the diffused light beam from No. 1 travels vertically downward in FIG. 1 and enters the first mirror 104a. First mirror 104
The light beam incident on a is reflected to the upper right of the carriage 107 at a predetermined angle, and is incident on the second mirror 104b disposed above the carriage 107. Second mirror 104b
Is reflected downward by the carriage 107 at a predetermined angle, and reenters the first mirror 104a. First
The light beam that has re-entered the mirror 104a is reflected at a predetermined angle to the upper right of the carriage 107, and is again reflected by the second mirror 10a.
4b. The light beam incident on the second mirror 104b is reflected at a predetermined angle below the carriage 107, and the third mirror 104c disposed on the lower end side of the carriage 107
Incident on. The light beam incident on the third mirror 104c is reflected in the horizontal direction with respect to the surface of the
6 forms an image on the line sensor 105 surface. The image information of the document 101 is read by moving the carriage 107 in the direction of arrow A (sub-scanning direction) shown in FIG.

In this specification, the upper side of the carriage refers to the document table 102 side, and the lower side refers to the opposite direction. The right side of the carriage is on the side of the sub-scanning motor 108, and the left side is the opposite direction.

As described above, in the present embodiment, the multiple reflection mirrors 104a and 104b, which tend to be large as described above, are used.
Alternatively, by disposing the first mirror 104a, which is the longest in the longitudinal direction, closer to the document 101 than the imaging lens 106, the relatively small imaging lens 106 and the line sensor 105, and only the mirrors other than those described above, it is possible to reduce the size of the carriage 107 in particular, as shown in FIG. 2, so that the space created at the bottom inside the image scanner main body is conventionally placed elsewhere. The power supply device, the image processing circuit, and the like that have been used can be arranged, which can contribute to downsizing of the entire device.

(Embodiment 2) FIG. 3 is a schematic view of a main part of Embodiment 2 when the image reading apparatus of the present invention is applied to an apparatus such as an image scanner. In the figure, the same elements as those shown in FIG. 1 are denoted by the same reference numerals.

The present embodiment is different from the first embodiment in that a plurality of scanning mirrors are constituted by four mirrors.
The carriage is configured by appropriately setting the arrangement positions of the mirrors. Other configurations and optical functions are substantially the same as those of the first embodiment, and thus, similar effects are obtained.

That is, in this embodiment, the plurality of scanning mirrors are the first, second, third, and fourth mirrors 204a, 204a.
4 b, 204 c, and 204 d, the light beam from the document 101 is reflected by the first mirror 204 a, then enters the second mirror 204 b, and is reflected by the second mirror 2.
The light beam reflected by the third mirror 204c is incident on the third mirror 204c, and the light beam reflected by the third mirror 204c is again transmitted to the second mirror 204c.
The mirrors are arranged such that the light beam is incident on the mirror 204b, the light beam reflected by the second mirror 204b is incident on the fourth mirror 204d, and the light beam reflected by the fourth mirror 204d is incident on the imaging lens 106. are doing.

In this embodiment, the first, second, third,
Fourth mirrors 204a, 204b, 204c, 204d
Of these, the second mirror 204b is a multiple reflection mirror that reflects the light beam from the document 101 a plurality of times, and the second mirror 204b is the longest vertical distance L ₁ from the reflection surface to the document table 102. Is shorter than the vertical distance L ₃ from the optical axis of the imaging lens 106 to the document table 102, and from the reflection surface of the first mirror 204 a that first reflects the light beam from the document 101 to the document table 102. Are arranged so that the vertical longest distance L ₂ is shorter than the vertical distance L ₃ from the optical axis of the imaging lens 106 to the document table 102.

In this embodiment, the light beam emitted from the light source 103 illuminates the lower surface of the original 101, and the original 10
Part of the diffused light beam from No. 1 travels vertically downward in FIG. 3 and enters the first mirror 204a. First mirror 204
The light beam incident on a is reflected to the upper right of the carriage 207 at a predetermined angle, and is incident on the second mirror 204b disposed above the carriage 207. Second mirror 204
The light beam incident on b is reflected at a predetermined angle below the carriage 207 and is incident on the third mirror 204c. The light beam incident on the third mirror 204c is reflected to the upper right of the carriage 207 at a predetermined angle, and is incident again on the second mirror 204b. The light beam incident on the second mirror 204b is reflected at a predetermined angle below the carriage 207, and is incident on a fourth mirror 204d disposed on the lower end side of the carriage 207. The light beam incident on the fourth mirror 204d is the original 101
The light is reflected in the horizontal direction with respect to the surface, and forms an image on the surface of the line sensor 105 by the imaging lens 106. The image information of the document 101 is read by moving the carriage 207 in the direction of arrow A (sub-scanning direction) shown in FIG.

(Embodiment 3) FIG. 4 is a schematic view of a main part of Embodiment 3 when the image reading apparatus of the present invention is applied to an apparatus such as an image scanner. In the figure, the same elements as those shown in FIG. 1 are denoted by the same reference numerals.

The present embodiment is different from the above-described first embodiment in that a plurality of mirrors for scanning are arranged at different positions to form a carriage. Other configurations and optical functions are substantially the same as those of the first embodiment, and thus, similar effects are obtained.

That is, in this embodiment, the plurality of scanning mirrors are the first, second, and third mirrors 304a, 304b,
The light beam from the document 101 is reflected by the first mirror 304a, then enters the second mirror 304b, and the light beam reflected by the second mirror 304b is again reflected by the first mirror 304c. The light beam incident on the first mirror 304a and reflected by the first mirror 304a
And the light beam reflected by the second mirror 304b is again incident on the first mirror 304a, and the first mirror 304a
The light beam reflected by the light enters the second mirror 304b again,
The mirrors are arranged such that the light beam reflected by the second mirror 304b enters the third mirror 304c, and the light beam reflected by the third mirror 304c enters the imaging lens 106.

In this embodiment, of the first, second and third mirrors 304a, 304b and 304c,
The second mirrors 304a and 304b are multiple reflection mirrors that reflect a light beam from the document 101 a plurality of times.
The longest vertical distances L ₁ and L ₂ from the reflecting surfaces of the second mirrors 304 a and 304 b to the document table 102 are respectively longer than the vertical distance L ₃ from the optical axis of the imaging lens 106 to the document table 102. is short, and platen a light beam from the original 101 longest distance L ₂ in the vertical direction from the first reflecting surface of the first mirror 304a which reflects up platen 102 from the optical axis of said imaging lens 106 102 It is arranged each element to be shorter than the vertical distance L ₃ to.

In this embodiment, the first and second mirrors 304a and 304b are arranged such that the reflection surfaces of the first and second mirrors 304a and 304b are substantially parallel to each other.

In the present embodiment, the light beam emitted from the light source 103 illuminates the lower surface of the original 101 and the original 10
Part of the diffused light beam from No. 1 travels vertically downward in FIG. 4 and enters the first mirror 304a. First mirror 304
The light beam incident on a is reflected at a predetermined angle to the upper right of the carriage 307, and is incident on the second mirror 304b disposed above the carriage 307. Second mirror 304
The light beam incident on b is reflected at a predetermined angle below the carriage 307, and is incident on the first mirror 304a again. The light beam that has re-entered the first mirror 304a is reflected to the upper right of the carriage 307 at a predetermined angle, and is again reflected by the second mirror 3a.
04b. The light beam that has entered the second mirror 304b is reflected downward by the carriage 307 at a predetermined angle, and enters the first mirror 304a again. First mirror 304a
The light flux incident again on the carriage 307 is reflected to the upper right of the carriage 307 at a predetermined angle, and is incident again on the second mirror 304b. The light beam incident on the second mirror 304b is reflected downward by the carriage 307 at a predetermined angle, and
Incident on the third mirror 304c disposed on the lower end side of the.
The light beam incident on the third mirror 304c is reflected in the horizontal direction with respect to the original 101 surface, and is imaged on the line sensor 105 surface by the imaging lens 106. And carriage 3
07 is moved in the direction of arrow A (sub-scanning direction) shown in FIG.

(Embodiment 4) FIG. 5 is a schematic view of a main part of Embodiment 4 when the image reading apparatus of the present invention is applied to an apparatus such as an image scanner. In the figure, the same elements as those shown in FIG. 1 are denoted by the same reference numerals.

The present embodiment is different from the first embodiment in that a plurality of scanning mirrors are constituted by five mirrors.
The carriage is configured by appropriately setting the arrangement positions of the mirrors. Other configurations and optical functions are substantially the same as those of the first embodiment, and thus, similar effects are obtained.

That is, in the present embodiment, the plurality of scanning mirrors are the first, second, third, fourth, and fifth mirrors 404.
a, 404b, 404c, 404d, and 404e. The light flux from the document 101 is reflected by the first mirror 404a, then enters the second mirror 404b, and is reflected by the second mirror 404b. Of the original 1
01 and passes through the optical path between the first mirror 404a and the third mirror 40c.
The light beam reflected by the first mirror 4c is reflected on the original 101 and the first mirror 4c.
After passing through the optical path between the original 101 and the first mirror 404a, the light beam re-enters the second mirror 404b, and the light beam reflected by the second mirror 404b crosses the optical path between the original 101 and the first mirror 404a. After passing through the document 1, the light is incident on the third mirror 404c again, and the light beam reflected by the third mirror 404c is
After passing through the optical path between the first mirror 404a and the first mirror 404a, the light enters the fourth mirror 404d,
The light beam reflected at 04d crosses the optical path between the second mirror 404b and the third mirror 404c, passes through the optical path, enters the fifth mirror 404e, and is reflected by the fifth mirror 404e. Each mirror is arranged so as to be incident on the imaging lens 106.

In this embodiment, the first, second, third,
Fourth and fifth mirrors 404a, 404b, 404c, 4
04d and 404e, the second and third mirrors 404
b and 404c reflect the light beam from the document 101 a plurality of times.
And the second and third mirrors 404.
b and 404c are lead from the reflection surface to the document table 102.
Longest distance L in the direct direction₁ , L_Two Of the imaging lens 106
Vertical distance L from optical axis to platen 102_Four than
The light beam that is short and reflects the light flux from the original 101 first.
From the reflection surface of the first mirror 404a to the platen 102
Longest distance L in vertical direction_Three Is the optical axis of the imaging lens 106
Vertical distance L from the document table to the platen 102 _Four Shorter than
Each element is arranged as follows.

In this embodiment, the first and second mirrors 404b and 404c are arranged so that the reflection surfaces of the second and third mirrors 404b and 404c are substantially parallel to each other.

In the present embodiment, the light beam emitted from the light source 103 illuminates the lower surface of the
A part of the diffused light beam from No. 1 travels vertically downward in FIG. 5 and enters the first mirror 404a. First mirror 404
The luminous flux incident on a is reflected obliquely upward and to the right of the carriage 407 at a predetermined angle, and is incident on the second mirror 404b disposed on the right side of the carriage 407. Second mirror 40
The light beam incident on 4b is reflected obliquely to the upper left of the carriage 407 at a predetermined angle, crosses the optical path between the document and the first mirror, and then enters the third mirror 404c. The light beam incident on the third mirror 404c is reflected obliquely to the upper right of the carriage 407 at a predetermined angle, crosses the optical path between the document and the first mirror, and then passes through the second mirror 404 again.
b. The light beam incident on the second mirror 404b is reflected obliquely to the upper left of the carriage 407 at a predetermined angle,
After passing across the optical path between the original and the first mirror, the light again enters the third mirror 404c. The light beam incident on the third mirror 404c is reflected obliquely to the upper right of the carriage 407 at a predetermined angle, crosses the optical path between the document and the first mirror, and is disposed on the upper end side of the carriage 407. The light enters the fourth mirror 404d. The light beam that has entered the fourth mirror 404d is reflected downward by the carriage 407 at a predetermined angle, crosses the optical path between the second mirror and the third mirror, and passes therethrough. 5 enters the mirror 404e. The light beam incident on the fifth mirror 404e is reflected in the horizontal direction with respect to the original 101 surface, and is imaged on the line sensor 105 surface by the imaging lens 106. Then, the carriage 407 is moved in the direction of arrow A (sub-scanning direction) shown in FIG.
01 image information is read.

In addition to the above-described embodiments, the present invention can be implemented in the same manner as the above-described embodiments, regardless of the configuration of the scanning optical system unit, provided that the configuration requirements of the present invention are satisfied. Can be applied.

[0052]

According to the present invention, in an image reading apparatus having a scanning optical system unit (carriage) as described above,
By configuring at least one of the plurality of mirrors constituting one element of the scanning optical system unit by a multiple reflection mirror, and by appropriately setting the arrangement of each element including the plurality of mirrors, With a small number of mirrors, a long optical path length can be secured despite a small scanning optical system unit.
Further, since the mirror, reading means, and imaging lens arranged at the bottom of the scanning optical system unit are all short in the longitudinal direction, the bottom of the scanning optical system unit can be downsized. A power supply device, an image processing circuit, and the like, which have been conventionally arranged in other places, can be arranged at the bottom of the main body, and an image reading apparatus that can reduce the size of the entire apparatus can be achieved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part according to a first embodiment of the present invention;

FIG. 2 is a perspective view of a main part of the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a main part according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a main part according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of a main part of a fourth embodiment of the present invention.

FIG. 6 is a configuration diagram of a main part of a conventional image reading apparatus.

FIG. 7 is a configuration diagram of a main part of a conventional image reading apparatus.

FIG. 8 is a perspective view of a main part of a conventional image reading apparatus.

[Explanation of symbols]

1 Image reading apparatus 101 Document (image) 102 Platen glass 103 Light source means 104a, 104b, 104c Mirrors 204a, 204b, 204c, 204d Mirrors 304a, 304b, 304c Mirrors 404a, 404b, 404c, 404d, 405e
Mirrors 107, 207, 307, 407 Scanning optical system unit (carriage) 106 Imaging lens 105 Reading means (line sensor) 108 Sub-scanning motor

Claims (6)

[Claims] A light source for illuminating a document placed on a document table; a plurality of mirrors for reflecting a light beam from the document illuminated by the light source means; and a light beam reflected by the plurality of mirrors. An image reading unit that moves a scanning optical system unit including an image forming lens for forming an image and reading means disposed at an image forming position of the image forming lens relative to the document to read image information of the document; In the apparatus, the plurality of mirrors include one or more multiple reflection mirrors that reflect a light beam from the document a plurality of times, and the one or more multiple reflection mirrors extend in a vertical direction from the reflection surface to the document table. The longest distance is shorter than the vertical distance from the optical axis of the imaging lens to the platen, and the platen of the plurality of mirrors reflects a light beam from the document firstly. The maximum vertical distance to Image reading apparatus characterized by shorter than a distance in the vertical direction to the platen from the optical axis of the lens. 2. A multi-reflection mirror for reflecting a light beam from a document a plurality of times, wherein the two multi-reflection mirrors are arranged such that their reflection surfaces are substantially parallel to each other. The image reading device according to claim 1, wherein: 3. The mirror according to claim 1, wherein the plurality of mirrors include first, second, and third mirrors, and a light beam from the document is reflected by the first mirror and then enters the second mirror. The light beam reflected by the second mirror again enters the first mirror, the light beam reflected by the first mirror again enters the second mirror, and the light beam reflected by the second mirror is reflected by the third mirror. 2. The image reading apparatus according to claim 1, wherein each mirror is arranged such that a light beam incident on the mirror and reflected by the third mirror is incident on the imaging lens. 4. The plurality of mirrors are first, second, third,
The fourth mirror is composed of four mirrors, and the light beam from the document is reflected by the first mirror, then enters the second mirror, and the light beam reflected by the second mirror enters the third mirror. Then, the light beam reflected by the third mirror enters the second mirror again, the light beam reflected by the second mirror enters the fourth mirror, and the light beam reflected by the fourth mirror is converged. 2. The image reading apparatus according to claim 1, wherein each mirror is arranged so as to be incident on the image lens. 5. The mirror according to claim 1, wherein the plurality of mirrors include first, second, and third mirrors, and a light beam from the document is reflected by the first mirror and then enters the second mirror. The light beam reflected by the second mirror again enters the first mirror, the light beam reflected by the first mirror again enters the second mirror, and the light beam reflected by the second mirror again enters the first mirror. The light beam incident on the mirror and reflected by the first mirror again
The mirrors are arranged such that the light beam reflected by the second mirror is incident on the mirror, the light beam reflected by the second mirror is incident on the third mirror, and the light beam reflected by the third mirror is incident on the imaging lens. The image reading device according to claim 1. 6. The plurality of mirrors are first, second, third, and third mirrors.
The light beam from the document is reflected by the first mirror, then enters the second mirror, and the light beam reflected by the second mirror is reflected by the document. After passing through the optical path between the first mirror and the first mirror, the light enters the third mirror, and the light beam reflected by the third mirror crosses the optical path between the document and the first mirror. After passing through, the light again enters the second mirror, and the light beam reflected by the second mirror crosses the optical path between the document and the first mirror, passes through the optical path again, and then enters the third mirror again. After the light beam reflected by the third mirror passes through the optical path between the original and the first mirror,
The light beam incident on the fourth mirror, reflected by the fourth mirror, crosses the optical path between the second mirror and the third mirror and passes through the fifth mirror. 2. The image reading device according to claim 1, wherein each mirror is arranged such that a light beam reflected by the mirror is incident on the imaging lens.