JPH0670091A - Picture reader - Google Patents

Abstract

PURPOSE:To provide accurate reproducing pictures by simple constitution and to easily exchange light sources by fixing the support and fixing of a mirror unit and a light source unit constituting a reading scanning apparatus with the fixing part of a central part and holding pins and chamfers at the both ends of the respective units. CONSTITUTION:The reading scanning apparatus 50 is constituted of the light source unit 54 and the mirror unit 58 and the chamfers 78 and corresponding chamfers are provided on the both ends of the unit 54 and are engaged to the corresponding pins 74 and 76 of the unit 58. Further, fixing members 70 and 86 are provided in the central part of the units 58 and 54 and the through- holes 70a and 86a are fixed with bolts and nuts, that is, the units 58 and 54 are fixed, at the both ends and at three point of central part. Then, when the units 58 and 54 are attached and detached, distortion due to the difference of the fixing power of the respective points is prevented and the deviation of the optical axes of a fluorescent lamp, a mirror 56 and a slit, etc., is eliminated. Thus, the fluorescent lamp can be easily exchanged and accurate pictures can be obtained by the simple constitution.

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 used in an image forming apparatus such as a printing plate making apparatus.
The present invention relates to an image reading device capable of accurately reading a reproduced image without causing distortion or deviation.

[0002]

2. Description of the Related Art An image reading apparatus used in an image forming apparatus such as a printing plate making apparatus and a copying apparatus has a reading scanner (hereinafter referred to as a scanning scanner) having a light source extending in a one-dimensional direction, for example, a fluorescent lamp or an LED array. The scanning light) is moved in a direction substantially orthogonal to the one-dimensional direction, so that the reading light emitted from the light source is two-dimensionally applied to the entire surface of the original on the original table.
The reflected light is reflected in a predetermined direction by using a plurality of mirrors. This reflected light is transmitted through an imaging lens and focused on a solid-state image pickup device such as a CCD arranged at a predetermined position, and the solid-state image pickup device photoelectrically converts the light into an electric signal. Or the reflected light that has passed through the imaging lens is focused on an image forming material such as a photosensitive material to obtain a reproduced image.

FIG. 5 shows a conceptual diagram of an example of such an image reading apparatus. The image reading apparatus shown in FIG.
1 is a document placing portion 12 on which the document face is placed face down.
A (scanning) scanner 100, a combination mirror 14 for changing the optical path of the reflected light L carrying the original image from the original 11, an imaging lens 15 for forming the reflected light, and a combination of the reflected light. The reading unit 16 is arranged at the image position and basically receives the reflected light L and photoelectrically reads image information.

The document placing section 12 presses the platen glass 17 made of a transparent glass plate and the document 11 placed on the platen glass 17 under pressure to prevent the document from being displaced. Composed of and.

Below the platen glass 17, a light source moving type scanning optical system including a scanning element 100 and a combination mirror 14 is arranged. In this scanning optical system, the scanning element 100 moves in the sub-scanning direction indicated by an arrow A in the figure at a predetermined speed (v) under the driving action of a driving mechanism (not shown), and the combination mirror 14 causes the scanning element 100 to move. Moves in the same direction at a speed (1/2 · v) that is half the moving speed of.

The scanner 100 is a fluorescent lamp 10 which is a rod-shaped light source which emits band-shaped reading light (slit light) in one direction.
2a, 102b, and a light source unit 10 having a light blocking plate 104 for blocking unnecessary incident angles (35 ° or less) of the reading light emitted from the fluorescent lamps 102a, 102b.
6 and a mirror unit 110 that has a first mirror 108 that reflects the reflected light L from the document 11 by 90 degrees and that engages with the drive mechanism of the scanning element 100. This scanner 1
Numeral 00 scans the original 11 two-dimensionally by moving in the direction of arrow A while irradiating the original 11 with the irradiation light from the fluorescent lamps 102a and 102b, and the reflected light L from the original is reflected by the first mirror 108. Reflects in a predetermined direction.

Reflected light L reflected by the first mirror 108
Are then introduced into the combination mirror 14. The combination mirror 14 is provided with a second mirror 31 and a third mirror 32 that deflect the optical path of the reflected light from the first mirror 108 every 90 degrees. The reflected light L reflected by the third mirror 32 is fixed to a predetermined position in the imaging lens 1
After passing through 5, the light enters the reading unit 16. The reading unit 16 is
It is arranged at the image forming position of the reflected light L by the image forming lens 15,
A CCD 33 and a CCD 33 for photoelectrically converting an original image of one line of an original illuminated by a predetermined band-shaped illumination light into an electric signal as image density data.
And an image processing device 34 for processing the data photoelectrically read by.

The CCD 33 is a licensor that photoelectrically converts an original image for one line of main scanning and outputs it as an analog image data signal for one line of main scanning, and is not limited to this and various licensors can be used. The image processing device 34 includes a clock generator that generates a main scanning clock that determines the timing of reading the image data of one main scanning line, and an analog image data signal read from the CCD 33 based on the main scanning clock. An image that is corrected and then converted into an image data signal as a digital signal, a memory that stores this digital image data, and an image that is processed as an image signal for recording and finally output as an image signal for recording. The recording image signal is output to an image recording device (not shown) including a processing unit and the like.

In such an image reading apparatus, the scanning element 100 has the fluorescent lamp 102 as the reading light source, as described above.
And a mirror unit 110 that holds the first mirror 108. Here, in a normal image reading apparatus, the mirror unit 1
The light source unit 106 is configured to be attachable to and detachable from the mirror unit 110.

The original 1 is irradiated by the irradiation light from the scanning element 100.
In an image reading device that scans 1 in two dimensions, in order to realize image reading with optical accuracy, it is necessary that the irradiation light from a fluorescent lamp or the like, which is a light source, always has a constant light amount and has no unevenness as a whole. is there. Therefore, it is necessary to promptly replace the light source when the light amount of the irradiation light decreases or when the light amount unevenness occurs in the one-dimensional direction. In particular, in applications requiring high-quality image reading such as printing plate making equipment, as a light source,
A fluorescent lamp called a high-brightness aperture type that has a slit and can emit a large amount of irradiation light in a predetermined direction is used, but while this fluorescent lamp can obtain a large amount of irradiation light, it can obtain a uniform amount of light without unevenness. The period (lighting time) is short, and it is necessary to replace the light source at a relatively short cycle.

Further, as is well known, it takes time for the light quantity of the fluorescent lamp to stabilize after being turned on. Therefore, most readers using a fluorescent lamp as a light source, especially those requiring high-quality reading, are mainly used. When the power is turned on, the fluorescent lamp, which is the reading light source, is turned on almost at the same time, and then it is turned on until the main power is turned off. Therefore, the cycle of exchanging the light source becomes shorter and shorter.

On the other hand, after the light source such as a fluorescent lamp is exchanged, in order to irradiate the original with a predetermined constant amount of irradiation light, the light source unit 106 (scanner 100) is in a predetermined position and in a predetermined state. It is necessary to accurately attach a light source such as a fluorescent lamp. Particularly, in the above-mentioned reader using a high-brightness aperture type fluorescent lamp in which the light irradiation direction is defined, it is necessary to accurately define the mounting angle of the fluorescent lamp in the circumferential direction.

Therefore, in such an image reading apparatus, the scanner 100 is composed of a mirror unit 110 which engages with the driving means, and a light source unit 106 which is detachably attached to the mirror unit 110. Light 1
02) when the light amount decreases or unevenness occurs,
The light source unit 106 can be easily replaced by the user.

[0014]

By the way, in the image reading apparatus using such a scanning element 100, the original 11
In order to make the irradiation position of the irradiation light to be accurate and to enable good image reading with a predetermined light amount, it is necessary to securely fix the light source unit 106 to the predetermined position of the mirror unit 110. Therefore, conventionally, such fixing of the light source unit 106 to the mirror unit 110 is performed by positioning with a positioning pin or the like and using bolts, nuts, screws or the like at four positions near the corners.

For example, in Japanese Patent Laid-Open No. 63-294069, an exposure light source unit (scanner) is composed of a lamp housing (light source unit) having a reading light source and a mirror holder (mirror unit) holding a mirror. An exposure light source unit is disclosed in which a reference protrusion for positioning is provided on a mirror holder for positioning, and a lamp housing and a mirror holder are fixed by four screws.

However, if the light source unit 106 and the mirror unit 110 are fixed at four or more places as in the conventional reader, the distortion of the light source unit 106 is transmitted to the mirror unit 110 (or vice versa). Further, the mirror unit 110 or the light source unit 106 is distorted due to the difference in fixing strength at each fixing place, and the first mirror 1 held by the mirror unit 110.
08 or the fluorescent lamp 102 held by the light source unit 106
However, there are problems such that the optical axis of the scanner is deviated, the movement of the scanning element 100 in the sub-scanning direction is incorrect, and the like.

Such an inconvenience results in an error in the incident position of the reflected light from the original 11 on the CCD 33, and when the read image is reproduced, image distortion, image recording position deviation, etc. occur. In particular, it becomes a problem in applications such as a printing plate making apparatus that require high accuracy in image size and shape, and image forming position.

In order to prevent such inconvenience, it is conceivable that both the light source unit 106 and the mirror unit 110 are made of a casing that is less likely to cause distortion.
In this case, the light source unit 106 and the mirror unit 11
Both of them are large and heavy, and there are problems that the degree of freedom in design is reduced, the load on the driving means is increased, and the cost is increased.

An object of the present invention is to solve the above-mentioned problems of the prior art. To eliminate the distortion (transmission of distortion) between the light source unit and the mirror unit due to the fixing, the size, shape, An object of the present invention is to provide an image reading apparatus capable of obtaining a reproduced image with an accurate output position and the like, and having a simple structure and easy replacement of a reading light source.

[0020]

In order to achieve the above object, the present invention emits reading light extending in a one-dimensional direction to a document placed on a document table, and reflects light reflected from the document. Image reading for reading a document image by two-dimensionally scanning a document placed on the document table by moving a reading scanner reflecting in a predetermined direction in a sub-scanning direction substantially orthogonal to the one-dimensional direction In the apparatus, the reading scanner includes a light source unit that holds a rod-shaped light source that emits the reading light, and a mirror unit that holds a mirror that reflects the reflected light from the document in a predetermined direction. Provided is an image reading device characterized in that a light source unit and a mirror unit are fixed at arbitrary three points.

Further, it is preferable that the mirror unit is engaged with the driving means of the reading scanning element so that the light source unit can be attached to and detached from the mirror unit.

[0022]

The image reading apparatus of the present invention holds a light source unit for holding a reading light source such as a fluorescent lamp, and a mirror for reflecting the reflected light emitted from the reading light source and reflected by the document in a predetermined direction. An image reading apparatus using a reading scanner, which comprises a mirror unit that engages with a driving unit of the reading scanner, and in which the light source unit is attachable to and detachable from the mirror unit, the light source unit and the mirror unit. Is fixed at any three points.

According to the present invention as described above, JP-A-63-
Unlike the conventional reading scanner disclosed in Japanese Patent No. 294069, which fixes at four places, the distortion of either one is not transmitted to the other by fixing the light source unit and the mirror unit, and Distortion does not occur in the light source unit or the mirror unit due to the difference in the fixing force at each fixing place. Therefore, in the image reading apparatus of the present invention, the optical axis of the reading light source or the mirror provided in the reading scanner is not deviated even though it has a simple structure, and the reading from the document is accurately performed by the reading scan. Light can be accurately incident on a predetermined position of a photoelectric conversion element such as a CCD, and moreover,
The reading light source such as a fluorescent lamp can be easily replaced with a simple configuration.

Therefore, according to the image reading apparatus of the present invention,
It is possible to realize accurate high-quality image reading of the recording position, size, etc. without distortion in the reproduced image.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The image reading apparatus of the present invention will be described in detail below with reference to the preferred embodiments shown in the accompanying drawings.
FIG. 1 conceptually shows an example of the image reading apparatus of the present invention.
The image reading apparatus shown in FIG.
Since it has basically the same configuration as the image reading apparatus shown in FIG. 5 except that is different, the same members are denoted by the same reference numerals, and the following description will be made mainly for different portions.

An image reading apparatus 10 shown in FIG. 1 is an image reading apparatus used in a printing plate making apparatus, and like the reading apparatus shown in FIG. 5, the reading scanner (hereinafter referred to as a scanner). 50 and the combination mirror 14 both move in a predetermined direction at a predetermined speed by a driving device 90 (see FIG. 4), and the original 11 is two-dimensionally scanned by the scanner 50. The scanner 50 has a predetermined speed. In (v), the combination mirror 14 moves in the sub-scanning direction indicated by an arrow A in the drawing, and the combination mirror 14 moves at a speed half the speed of the scanning element 50 (1/2).
・ In v), move in the same direction. The reading light emitted from the scanning element 50 is reflected by the original 11 and is reflected in a predetermined direction by the scanning element 50, and then the combination mirror 1
It is reflected in a predetermined direction by 4 and enters the imaging lens 15, and is photoelectrically converted by the CCD 33 and read.

The image information read by the CCD 33 is sequentially transferred to the image processing device 34, and the halftone image information R
Is transferred to an image recording device (not shown). The image processing device 34 includes a clock generator that generates a main scanning clock that determines a timing of reading image data of one main scanning line from the CCD 33, and a CC based on the main scanning clock.
An analog image data signal read from D33 is subjected to analog correction such as gain correction and then converted into an image data signal as a digital signal, a memory for storing this digital image data, and this image data signal Is image-processed as a final halftone dot image signal R,
It is composed of an image processing unit for transferring to an image recording device.
Here, the image processing unit stores various data including a processing circuit that performs various processes described below necessary for generating a halftone image signal, a CPU that performs various image data signal calculations and determinations, and image data. Memory such as RAM and ROM.

In the image reading apparatus 10 shown in FIG. 1, the scanning element 50 basically has a fluorescent lamp 52 as a light source.
From a light source unit 54 that holds a and 52b, and a mirror unit 58 that holds a first mirror 56 that reflects the reflected light L from the original document in a predetermined direction and that engages with a driving device 90 of the scanning element 50 described later. Composed.

In the scanner 50 of the illustrated example, the light source unit 54 emits band-shaped reading light (slit light) in one direction, so-called high-brightness aperture type fluorescent lamp 52.
The angle between a and 52b and the reflected light L from the document 11 is 3
And a light blocking plate 60 that blocks the illumination light of less than 5 degrees. On the other hand, the mirror unit 58 holds the first mirror 23, which reflects the reflected light L from the document 11 by 90 degrees, at a predetermined position at a predetermined angle, and the fixed end 9 of the driving device 90 for the scanning element 50.
8a and 98b are fixed to the bottom surface and engaged with the drive device 90 (see FIG. 4).

FIG. 2 is a schematic perspective view of the light source unit 54 and the mirror unit 58, and FIG. 3 is an exploded schematic perspective view of the same. 2 and 3, although omitted for simplification of the drawings, the light source unit 54 and the mirror unit 58 are assembled by using fixing means such as screws or bolts and nuts as necessary. Of course.

As shown in FIGS. 2 and 3, the light source unit 54 includes a U-shaped main body 62 and side end surfaces which engage with both end surfaces of the main body 62 in the longitudinal direction (a method substantially orthogonal to the direction of arrow A). It is a casing constituted by 64a and 64b, and a lid 66 that engages with the upper surface of the main body 62 (U-shaped open side). In such a light source unit 54,
A light shielding plate 60 having a U-shaped cross section is arranged so as to divide the inside of the main body 62 into two, and the fluorescent lamps 52a and 52b are arranged so as to sandwich the light shielding plate 60. Here, the fluorescent lamps 52a and 52b are illumination light (slit light) that is strip-shaped in one direction.
Is a so-called high-brightness aperture type, and is arranged and fixed with an angle in the circumferential direction so that the reading light is incident on the reflected light L from the original 11 at an angle of approximately 35 degrees or more. .

The light-shielding plate 60 is a member having a U-shaped cross section as described above, and regulates the reading light emitted from the strip-shaped slits of the fluorescent lamps 52a and 52b at the upper end, and reflects the light L reflected from the original 11. The reading light having an angle of less than 35 degrees does not enter the document surface. With such a configuration, that is, by restricting the incident angle of the reading light from the fluorescent lamp on the original 11 to 35 degrees or more with respect to the reflected light L, the original 1
(1) It is possible to eliminate the influence of the unevenness of the surface on the reproduced image and obtain a reproduced image of high quality in which only the image information on the document is clearly reproduced. This point is described in detail in Japanese Patent Application No. 3-71726 filed by the present applicant.

Slits 62a and 60a for passing the reflected light L from the original 11 are formed on the bottom surfaces of the main body 62 and the light shielding plate 60, respectively. Further, at the lower end of the center of the side surface of the main body 62, the mirror unit 5
Through hole 70a used for fixing to the bracket 68 of No. 8
Is provided with a fixing member 70.

The side end surfaces 64a and 64b fix the sockets 72a and 72b of the fluorescent lamps 52a and 52b to the inner wall surfaces of the casing, respectively. Here, it goes without saying that the respective sockets 72 are fixed so that the emission direction of the irradiation light from the fluorescent lamp 52 is the above-mentioned predetermined direction.
Notches 78 and 80 that engage with holding pins 74 and 76 provided on the bracket 68 are formed at the lower ends of the side end surfaces 64a and 64b, respectively.

The lid 66 closes the upper surface of the main body 62, and has an opening 66a through which the reading light from the fluorescent lamps 52a and 52b and the reflected light L from the document 11 pass. .

On the other hand, the mirror unit 58 is driven by a driving device 90.
The first mirror 56 and the bracket 68 that holds the first mirror 56. Near the center of the bracket 68, holding surfaces 82 and 84 are formed so as to be bent downward, and the holding surfaces 82 and 84 hold holes 82a for holding the first mirror 56 at a predetermined angle. And 84a are formed. Both ends of the first mirror 56 are inserted into the holding holes 82a and 84a, respectively, and are pressed by a leaf spring (not shown) or the like to be held at a predetermined position of the bracket 68 at a predetermined angle.

On both end faces of the bracket 68 in the longitudinal direction,
Holding pins 74 and 76 that engage with the notches 78 and 80 of the light source unit 54 are formed so as to project inward, and a through hole 86a corresponding to the fixing member 70 of the light source unit 54 is formed at the center in the longitudinal direction. Fixing member 86 having
Is formed. Further, fixed ends 98a and 98b of a drive device 90 described later are fixed to bottom surfaces 88a and 88b near the ends of the bracket 68.

The scanning element 50 is constructed such that the light source unit 54 is mounted and fixed on the mirror unit 58 that engages with the driving device 90. Here, for positioning and fixing the light source unit 54 to the mirror unit 58, the holding pin 74 of the mirror unit 58 (bracket 68) is engaged with the light source unit 54 notch 78, and similarly, the holding pin 76 is engaged with the notch 80. Then, the fixing member 70 of the light source unit 54 and the fixing member of the mirror unit 58 are fixed by known means such as bolts, nuts, and screws, thereby performing three-point support.

Therefore, unlike the conventional scanner that fixes the light source unit and the mirror unit by four points, the light source unit 54 and the mirror unit 58 are fixed (attached / detached).
Depending on which one distortion is transmitted to the other,
Distortion or the like does not occur in any one (the mirror unit 58 in the illustrated example) due to the distortion due to the difference in the fixing force at each point, and when the light source unit 54 is replaced, the fluorescent lamp is also replaced. 52a, 52b, first mirror 5
6, the optical axes of the slits 60a, 62a, etc. will not be displaced. Further, the structure of the scanning element 50 is simple, and the fluorescent lamp as the reading light source can be easily replaced. Therefore,
The reading light from the fluorescent lamps 52a and 52b is at a predetermined reading position of the original document 11, and the reflected light L from the original document 11 passes through a predetermined optical path and is incident on a predetermined position of the CCD 33 to perform accurate image reading. Therefore, it is possible to obtain a reproduced image having an accurate image size and an accurate image recording position without distortion.

In the illustrated example, the light source unit 5
4, the mirror unit 58 is constituted by the bracket 68, and the number of parts of the scanner 50 is reduced, the weight and the size thereof are reduced, the cost of the image reading apparatus is reduced, and the optical system is freely designed. It has improved the degree and reduced the weight.

In the image reading apparatus 10 of the present invention, the fixing of the light source unit 54 and the mirror unit 58 is not limited to the combination of a holding pin, a notch, a screw and the like as shown in the figure. Screws or bolts and nuts or the like may be used at all points, or the holding pin and the notch are configured to be strongly fitted to each other, and the three points are supported and fixed by the holding pin and the notch. May be Alternatively, an engaging member such as unevenness that engages with each other may be provided to support and fix the member. Further, the light source unit 54 and the mirror unit 58 are not limited to being supported / fixed on one side surface and both side end surfaces (side end surfaces 64a and 64b) as shown in the figure, but the three side surfaces. May be used for supporting / fixing, or the supporting / fixing may be carried out at side end surfaces at all three positions. That is, in the image reading apparatus of the present invention, the light source unit 54 can be reliably operated at three points.
And the mirror unit 58 can be supported / fixed,
The fixing point and the supporting / fixing method are not limited at all, and a good supporting point may be appropriately selected according to the configuration and design of the reading device (optical system).

As described above, the scanner 50 of the illustrated example has the bottom surface 88 of the bracket 68 which constitutes the mirror unit 58.
a and 88b are engaged with the drive device 90 by being fixed to the fixed ends 98a and 98b of the drive device 90, and are configured by mounting and fixing the light source unit 54 on the mirror unit 58. It Figure 4
A schematic plan view of the drive device 90 is shown in FIG.

The drive device 90 includes a drive motor 92, a speed reduction means 93, a wire drive pulley 94, wires 95a and 95b, movable pulleys 96a and 96b attached to both ends of the mirror unit 35, a plurality of idlers 97a and 97b and.

In the driving device 90, the rotation of the driving motor 92 such as a pulse motor (stepping motor) is decelerated by the deceleration means 93 such as a belt transmission means and transmitted to the wire drive pulley 94. A wire 95a shown by a chain double-dashed line in FIG. 2 has one end connected to the wire 96a on the right side in the drawing through a spring.
7a, movable pulley 96a, idler 97 (right side), wire drive pulley 94, idler 97 (left side), fixed end 98a of light source unit 31, and movable pulley 96a. The other end of wire 95a is fixed to wire fixed end 99a. Fixed. Here, the fixed end 98a is fixed to the bottom surface 88a of the bracket 68 as described above. Similarly, the wire 95b indicated by the alternate long and short dash line in FIG. 4 includes an idler 97b (right side), a movable pulley 96b, an idler 97b, an idler 97 (right side), and a wire drive pulley 9 from the connection side of the wire 95a.
4, idler 97 (left side), idler 97b (left side),
It is fixed to the wire fixed end 99b via the fixed end 98b of the light source unit 31 and the movable pulley 96b. Similarly, the fixed end 98b is fixed to the bottom surface 88b of the bracket 68.

Each of the wires 95a and 95b is wound around the wire drive pulley 94 at least once, and the wires 95a and 95b are rotated by the rotation of the wire drive pulley 94.
The light source unit 31 is wound or unwound to move the light source unit 31 at a predetermined moving speed, for example, the scanning speed, and at the same time, the mirror unit 35 is moved at half the speed thereof. Here, to change the moving speed of the light source unit 31, that is, the scanning speed during the pre-scanning and the main scanning, the rotation speed of the motor 92 itself may be changed, or the rotation speed may be changed by the speed reduction means 93.

Although the image reading apparatus of the present invention has been described above in detail, the present invention is not limited to the above-described embodiments, and various improvements and changes may be made without departing from the gist of the present invention. Of course.

[0047]

As described in detail above, in the image reading apparatus of the present invention, the light source unit and the mirror unit which constitute the reading scanner are supported and fixed at three points, so that the light source unit and the mirror are fixed. By fixing with the unit, the distortion of either one is not transmitted to the other,
Further, the light source unit or the mirror unit is not distorted due to the difference in the fixing force at each fixing place. Therefore, in the image reading apparatus of the present invention, although the reading light source such as a fluorescent lamp can be easily replaced with a simple configuration, the reading light source or the optical axis of the mirror provided in the reading scanner may be out of alignment. The reflected light from the original with accurate scanning without a CCD
Since it can be accurately incident on a predetermined position of the photoelectric conversion element such as, the reproduced image does not have distortion, etc., and realizes image reading that can obtain a reproduced image with high quality such as recording position, size, and shape. Therefore, it can be suitably used as an image reading apparatus of an image forming apparatus which requires high precision in image size of a printing plate making apparatus or the like.

[Brief description of drawings]

FIG. 1 is a diagram conceptually showing an example in which the image reading apparatus of the present invention is used in an image reading apparatus for a printing plate making apparatus.

FIG. 2 is a schematic perspective view of a reading scanner used in the image reading apparatus shown in FIG.

FIG. 3 is a schematic exploded perspective view of the reading scanner shown in FIG.

FIG. 4 is a schematic top view showing an example of a driving device of the image reading apparatus shown in FIG.

FIG. 5 is a conceptual diagram showing a conventional image reading device.

[Explanation of symbols]

 Reference Signs List 10 image reading device 11 document 12 document placing part 14 combination mirror 15 imaging lens 16 reading part 17 platen glass 18 document pressing plate 31 second mirror 32 third mirror 33 CCD 34 image processing device 50, 100 scanner 52a, 52b , 102a, 102b Fluorescent lamp 54, 106 Light source unit 56 First mirror 58, 110 Mirror unit 60, 104 Light shielding plate 62 Main body 64a, 64b Side end face 66 Lid 66a Opening 68 Bracket 70, 86 Fixing member 70a, 86a Through hole 72a , 72b Sockets 74, 76 Holding pins 78, 80 Notches 82, 84 Holding surfaces 82a, 84b Holding holes 88a, 88b Bottom surface 90 Drive device 92 Motor 93 Speed reducer 94 Wire drive pulley 95a, 95b Wire 96a, 96b Movable pulley 7,97a, 97b idler 98a, 98b fixed end 99a, 99b wire fixed end

Claims (2)

[Claims] 1. A reading scanner, which emits reading light extending in a one-dimensional direction to a document placed on a document table and reflects reflected light from the document in a predetermined direction, is substantially orthogonal to the one-dimensional direction. An image reading device that two-dimensionally scans a document placed on the document table to read a document image by moving in the sub-scanning direction, wherein the reading scanner emits the reading light. A light source unit for holding a rod-shaped light source, and a mirror unit for holding a mirror that reflects the reflected light from the original document in a predetermined direction. The light source unit and the mirror unit are fixed at arbitrary three points. An image reading device characterized by. 2. The image reading apparatus according to claim 1, wherein the mirror unit is engaged with a driving unit of a reading scanner, and the light source unit is detachable from the mirror unit.