JPH11155046A - Image read device provided with illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable obtaining a circuit system with less noise, by which a reflection original and a transmissive original are read without using plural light sources, by changing-over the optical path of illumination light emitted from the light source through the use of an optical path change-over means and permitting light to be selectively made incident to one of a first light guide means or a second light guide means. SOLUTION: An optical path change-over mirror 2 is the one for permitting illumination light emitted from a halogen lamp 1 to selectively made incident to one of a transmissive original optical fiber 4 or a reflection original optical fiber 5. The optical path change-over mirror 2 is fitted in a direction indicated by an arrow B with an axis 2a as a rotation center so as to be rotatable. The mirror 2 is rotated from a first position where illumination light is made incident by an angle being about 45 deg. as against a reflection surface 2b to the second position where the reflection surface 2b of the mirror 2 is made to be almost in parallel with illumination light. A transmission original illumination rod 6 and a reflection original illumination rod 7 are changed-over by the mirror 2 so as to be used so that the device configuration is simplified.

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 having an illuminating device for reading a reflection original such as a print image, which is a flat original, and a transparent original such as a film image.

[0002]

2. Description of the Related Art FIG. 8 shows an example of a conventional apparatus. Reflection manuscript,
An image reading apparatus capable of reading a transparent original has a light source for a reflective original and a light source for a transparent original, and switches the lighting when reading each original to read an image. As shown in FIG. 8, rod-shaped fluorescent tubes 31a and 31b are used as the light source of the image reading device, and have lighting circuits 33a and 33b, respectively.

The original 35 is read while the original 35 is transported in the direction of the arrow in FIG. 8 by an original transport mechanism (not shown). When the original 35 is a transparent original, the original 35 is illuminated by the fluorescent tube 31a and the original 35 is reflected. The original is illuminated by the fluorescent tube 31b. The illumination light reflected or transmitted by the original surface of the original 35 is bent by a mirror 36 to form an image on an imaging surface of a CCD 38 serving as a photoelectric conversion element via an imaging lens 37, and is read by the CCD 38. C
The CD 38 converts light formed by the imaging lens 37, that is, light related to the image of the original 35, into an electric image signal. The CCD 38 is a line sensor that scans one predetermined line of the document 35 by one reading. The transport speed of the document 35 is determined by the reading width of one line of the CCD 38 and the time required for reading one line.

[0004]

However, in the above arrangement, the light amount drift (unevenness) of the fluorescent tubes 31a and 31b is large, and a waiting time is required until the start of reading in order to secure a stable illumination state. You. Further, since a plurality of fluorescent tubes and lighting circuits are required, problems such as high cost and increased space occupation are caused. In addition, lighting of the fluorescent tube is performed by using a high frequency voltage, and this high frequency voltage causes a problem of unnecessary radiation of noise.

In order to solve the above-mentioned problems, the present invention provides an image reading apparatus having an illuminating device capable of reading a reflection document and a transmission document without using a plurality of light sources and having a circuit system with less noise. The purpose is to do.

[0006]

According to a first aspect of the present invention, there is provided an image reading apparatus having an illumination device, wherein an optical path of illumination light emitted from a light source is switched by an optical path switching means. The light was selectively incident on one of the first light guide and the second light guide. According to a second aspect of the present invention, in the image reading apparatus having the illumination device according to the first aspect, the light source is a halogen lamp.

According to a third aspect of the present invention, in the image reading apparatus having the illuminating device according to the first aspect, the first light guide means includes a first transmitting section for transmitting the illuminating light, and a illuminating light transmitted from the side. A first illuminating unit for illuminating the original by irradiating, and a second light transmitting unit for transmitting illumination light;
A second illuminator for illuminating the original by illuminating the document with illumination light from the side, wherein the first transmitter has one end connected to the end of the first illuminator and the other end disposed on the optical path of the light source. The second transmission unit has one end connected to the end of the second illumination unit and the other end arranged on the optical path of the light source.

According to a fourth aspect of the present invention, in the image reading apparatus having the illuminating device according to the third aspect, the first illuminating section and the second illuminating section are arranged at positions facing each other with the document therebetween. I decided to. According to a fifth aspect of the present invention, in the image reading apparatus having the illuminating device according to the first aspect, the optical path switching means includes an optical member for refracting the illumination light, and is used only when the optical path of the illumination light is switched. It is arranged on the optical path of the light source.

According to a sixth aspect of the present invention, in the image reading apparatus having the illuminating device according to the fifth aspect, the optical path switching means is a mirror. According to a seventh aspect of the present invention, in the image reading apparatus having the illuminating device according to the fifth aspect, the optical path switching means is a prism.
According to a ninth aspect of the present invention, in the image reading apparatus having the illuminating device according to the first aspect, the image reading apparatus further includes a light amount adjusting means for adjusting the amount of illumination light emitted from the light source. According to a fourth aspect of the present invention, in the image reading apparatus having the illuminating device according to the eighth aspect, the light amount adjusting means is disposed on an optical path between the light source and the optical path switching means.

According to a tenth aspect of the present invention, in the image reading apparatus having the illuminating device according to the eighth aspect, the light amount adjusting means is a plate member having a plurality of openings of different sizes. According to an eleventh aspect of the present invention, in the image reading apparatus having the illuminating device according to the eighth aspect, the light amount adjusting means blocks the illumination light.

According to a twelfth aspect of the present invention, in the image reading apparatus having the illuminating device according to the eighth aspect, the optical path switching means and the light amount adjusting means are integrally formed.

[0012]

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. Note that the image reading device of the present invention is the same as the conventional one except for the illumination device, and thus the description is omitted here.

FIG. 1 is a perspective view showing an illumination device of an image reading apparatus according to a first embodiment of the present invention. FIG. 2 is a top view of the illumination device of the image reading device according to the first embodiment of the present invention. FIG. 3 is a perspective view showing a driving mechanism of the optical path switching mirror 2 according to the first embodiment of the present invention. FIG. 4 is a front view showing a drive mechanism of the diaphragm plate 3 according to the first embodiment of the present invention. FIG. 5 is an explanatory view showing the structure of a rod-type illumination system.

Hereinafter, each configuration of the illumination device in the image reading apparatus of the first embodiment will be described. As shown in FIG. 1, the illumination device in the image reading apparatus includes a light source 1, an optical path switching mirror 2, an aperture plate 3, a transmission original optical fiber 4, a reflection original optical fiber 5, a transmission original illumination rod 6, and a reflection original illumination rod. It comprises an illumination rod 7, a light shielding wall 8, a mirror driving motor 11, and an aperture plate driving motor 12.

The light source 1 emits illumination light for illuminating the document 10. The light source 1 is desirably a stable light source having no uneven light amount, and an example thereof is a halogen lamp. The light source 1 is turned on by a lighting circuit (not shown).
Here, if the light source 1 is a halogen lamp, a high frequency voltage is not required for lighting, so that a circuit system with less influence of noise can be provided. The light source 1 also irradiates light beams emitted in directions other than the illumination direction indicated by the arrow A in FIG.

The optical path switching mirror 2 is for selectively causing the illumination light emitted from the light source 1 to be incident on one of a transmission original optical fiber 4 and a reflection original optical fiber 5 to be described later. The optical path switching mirror 2 includes a shaft 2a.
Is mounted so as to be rotatable in the direction indicated by arrow B in FIG. The optical path switching mirror 2 reflects the reflected light of the mirror 2 indicated by a dotted line in FIG. 2 from a first position where the illumination light enters the reflecting surface 2b of the mirror 2 indicated by a solid line in FIG. The surface 2b rotates to a second position where the illumination light is substantially parallel. The driving force for driving the mirror 2 is supplied by a mirror driving motor 11. FIG. 3 shows a drive mechanism of the optical path switching mirror 2. The optical path switching mirror 2 has a gear 2c attached to a rotating shaft 2a, and the gear 2c meshes with a driving gear 11b attached to a driving shaft 11a of a mirror driving motor 11. The driving force of the mirror driving motor 11 is a driving gear 11b.
To the gear 2c of the optical path switching mirror 2 Thus, the optical path switching mirror 2 rotates around the rotation axis 2a as a rotation center, and can change the direction of the mirror 2. The optical path switching mirror 2 refracts the optical path from the light source 1 by being driven to a first position indicated by a solid line in FIG. As a result, the illumination light is incident on the end face 5a of the reflection original optical fiber 5. The optical path switching mirror 2 is the same as that shown in FIG.
Is driven to the second position indicated by the dotted line to allow the illumination light to pass through. As a result, the illumination light is incident on the end face 4a of the optical fiber 4 for the transmission original.

An aperture plate 3 as a light amount adjusting means is for adjusting the light amount of the illumination light emitted from the light source 1. The diaphragm plate 3 is a plate member in which a plurality of openings having different sizes are formed. The aperture plate 3 is disposed on the optical path from the light source between the light source 1 and the optical path switching mirror 2 such that the plate surface intersects the light path substantially perpendicularly. The amount of illumination light is adjusted according to the size of the opening of the aperture plate 3. Aperture plate 3
Is mounted so as to be drivable in the direction of arrow C in FIG. A driving force for driving the aperture plate 3 is supplied by an aperture plate drive motor 12. FIG. 4 shows a drive mechanism of the aperture plate 3. The aperture plate 3 has a gear portion 3b at an end in a direction parallel to a driving direction indicated by an arrow C in FIG.
The gear portion 3b serves as a drive shaft 12 of the aperture plate drive motor 12.
a meshes with the drive gear 12b attached to the drive gear 12a.
The driving force of the diaphragm driving motor 12 is transmitted to the gear 3b of the diaphragm 3 via the driving gear 12b. Further, as shown in FIG. 1, the aperture plate 3 is provided with a light shielding portion 3a that does not allow illumination light to pass therethrough. The light shielding unit 3a is used to measure dark current of a photoelectric conversion element (not shown) in an image reading operation.
The illumination light from the light source 1 is blocked. In addition, by setting the aperture plate to the light shielding portion 3a when image reading is not performed, it is possible to prevent fading of the document 10 due to illumination light.

The transmission original optical fiber 4 transmits the illumination light emitted from the light source 1 to a transmission original illumination rod 6 described later. The end face 4a of the optical fiber 4 for the transmission original is arranged on the optical path of the light source 1, and the end face 4b is connected to the end of the illumination rod 6 for the transmission original. The reflection original optical fiber 5 is for transmitting illumination light emitted from the light source 1 to a reflection original illumination rod 7 described later. The reflective original optical fiber 5 has an end face 5 a disposed on the optical path of the light source 1 refracted by the optical path switching mirror 2, and an end face 5 b connected to an end of the reflective original illumination rod 7.

The illumination rod 6 for a transparent original is for illuminating the original 10 when the original 10 is a transparent original. The reflection original illumination rod 7 illuminates the original 10 when the original 10 is a reflection original. In the present embodiment, a rod-type illumination system described later is used as the illumination rod 6 for the transparent original and the illumination rod 7 for the reflective original. The illumination rod 6 for the transmissive original and the illumination rod 7 for the reflective original are placed at positions opposed to each other with the original 10 interposed therebetween.
0 is arranged so as to illuminate the original surface. The illumination rod 6 for the transmission original and the illumination rod 7 for the reflection original are arranged in a direction in which the longitudinal direction of the rod intersects the conveying direction of the original 10 indicated by an arrow D in FIG. The length of the illumination rod 6 for the transmission original and the illumination rod 7 for the reflection original are
It is desirable to have a length that can sufficiently illuminate the reading range of the photoelectric conversion element (not shown).

Here, a rod-type illumination system used for the illumination rod 6 for the transparent original and the illumination rod 7 for the reflective original will be described with reference to FIG. This rod type illumination system is also disclosed in Japanese Patent Publication No. 60-118806. The rod 42 is a rod having a circular cross section made of quartz glass, optical glass, silicon resin, or the like. Rod 42
It is desirable that the resin has high transparency and excellent light resistance. In FIG. 5, on the outer peripheral surface of the rod 42 and the surface of the end surface 42b other than the illumination direction indicated by the dotted arrow, a diffuser 43 for preventing the illumination light from diverging in unnecessary directions and preventing the illumination efficiency from lowering. Is formed. Diffuser 43 is rod 4
It is desirable that the material be a material having a higher refractive index than the material forming 2. Accordingly, the light traveling from the inside of the rod 42 toward the diffuser 43 undergoes total reflection at the boundary surface between the rod 42 and the diffuser 43, so that it is possible to prevent the illuminating light from diverging in unnecessary directions. I can do it. The diffuser 43 also has an effect of diffusing the illumination light when reflecting it. Examples of such a diffusion material 43 include barium sulfate, magnesia, and titania. As a result, when the illumination light of the light source 41 is incident from the end surface 42a of the rod 42, the illumination light repeats total reflection at the boundary between the rod 42 and the diffused substance 43,
It is output in the illumination direction indicated by the dotted arrow in FIG.

The light-shielding wall 8 is for preventing light from leaking from around the optical path switching mirror 2 and from entering the non-incident optical fiber of the transmission original optical fiber 4 and the reflection original optical fiber 5. . As shown in FIG. 2, the light-shielding wall 8 is provided at three locations 8a, 8b, and 8c. The light shielding wall 8a is connected to the rotation axis 2a of the optical path switching mirror 2.
To prevent the illumination light from leaking from the surrounding area. The light shielding wall 8b prevents the illumination light from leaking from between the mirror 2 and the diaphragm plate 3 when the optical path switching mirror 2 is at the first position shown by the solid line in FIG. The light blocking wall 8c prevents the illumination light from leaking from between the mirror 2 and the diaphragm plate 3 when the optical path switching mirror 2 is at the second position shown by the dotted line in FIG.

When the light path switching mirror 2 is at the first position shown by a solid line in FIG. 2, the light shielding wall 8 is illuminated by the mirror 2 and the light shielding walls 8a and 8b to enter the transmission original optical fiber 4. Close up. When the optical path switching mirror 2 is located at the second position shown by the dotted line in FIG. 2, the light shielding wall 8 controls the illumination light incident on the reflective original optical fiber 5 by the mirror 2 and the light shielding walls 8a and 8c. Block.

Next, the operation when the optical path conversion mirror 2 is at the first position shown by the solid line in FIG. 2 will be described. The amount of illumination light emitted from the light source 1 is adjusted by passing through the aperture plate 3, and then the light path is refracted by being reflected by the reflection surface 2 b of the optical path switching mirror 2. The illumination light whose optical path has been switched enters the end face 5a of the reflection original optical fiber 5. The illumination light incident on the reflection original optical fiber 5 is transmitted through the fiber 5 and is incident on the end of the reflection original illumination rod 7 from the end face 5 b of the fiber 5. The illumination light that has entered the illumination rod 7 for the reflective original is illuminated from the side surface of the illumination rod 7 to become linear illumination light to illuminate the original 10.

Next, the operation when the optical path conversion mirror 2 is at the second position shown by the dotted line in FIG. 2 will be described. The amount of illumination light emitted from the light source 1 is adjusted by passing through the diaphragm plate 3. The illumination light whose light amount has been adjusted passes through the optical path switching mirror 2 and is incident on the end face 4a of the optical fiber 4 for a transparent original. The illuminating light incident on the optical fiber 4 for the transmission original is transmitted through the fiber 4 and enters the end of the illumination rod 6 for the transmission original from the end face 4 b of the fiber 4. The illumination light that has entered the illumination rod 6 for the transparent original is illuminated from the side surface of the illumination rod 6 to become linear illumination light to illuminate the original 10.

As a result, the illumination light from the light source 1 is switched between the illumination rod 6 for the transmission original and the illumination rod 7 for the reflection original by the optical path switching mirror 2, so that the configuration of the apparatus can be simplified. In addition, by using a halogen lamp having high stability as a light source, the problem of drift due to the use of a fluorescent tube can be solved.

A diaphragm plate 3 for adjusting the amount of illumination light
Is provided, a sufficient amount of light can be given to a document having a very wide range of document densities, such as a transparent document, particularly a photographic film, and a high-quality image can be read. Note that the light source 1 in the present embodiment includes:
This corresponds to the light source in the claims of the present invention. Further, the optical path switching mirror 2 in the present embodiment corresponds to the optical path switching means in the claims of the present invention.

The aperture plate 3 in this embodiment corresponds to the light amount adjusting means in the claims of the present invention. Also,
The optical fiber 4 for the transmission original and the optical fiber 5 for the reflection original in the present embodiment are the first optical fiber in the claims of the present invention.
It corresponds to the first transmission section of the light guide means and the second transmission section of the second light guide means.

Further, the illumination rod 6 for the transparent original and the illumination rod 7 for the reflective original in the present embodiment are the first illumination part of the first light guide means and the second illumination of the second light guide means in the claims of the present invention. Corresponding to the department. (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. In the description of the second embodiment, only portions different from the first embodiment will be described, and common portions will be denoted by the same reference numerals in the drawings, and redundant description will be omitted.

FIG. 6A is a perspective view showing the optical path switching mirror 2 and the aperture plate 3 in the second embodiment of the present invention.
FIG. 6B shows an optical path switching mirror 2 shown in FIG.
And aperture plate 3, light source 1 and optical fiber 4 for transmission original
FIG. 4 is a top view showing the positional relationship between the optical fiber and the reflection original optical fiber. As shown in FIG. 6, the illumination device according to the second embodiment has a triangular prism-shaped optical path switching mirror 2 attached to a surface of the diaphragm plate 3 on the light source 1 side to be integrated. Also,
As shown in FIG. 6B, the optical path switching mirror 2 is fixed such that the reflection surface 2b forms an angle of about 45 degrees with respect to the incident direction of the illumination light. Then, when switching the optical path, the diaphragm plate 3 is driven to insert the optical path switching mirror 2 on the optical path of the light source 1. As a result, the optical path is refracted by about 90 degrees on the reflecting surface 2b of the optical path switching mirror 2 and enters the end face 5a of the reflecting original optical fiber 5. In the case of the second embodiment, the light path is refracted before passing through the stop plate 3. Therefore, the diaphragm plate 3 is disposed on the optical path between the optical fiber 4 for the transmission original and the optical fiber 5 for the reflection original.

Thus, in addition to the effects of the first embodiment,
Since a driving mechanism for rotating and driving the optical path switching mirror 2 can be omitted, the apparatus can be further simplified. Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. In the description of the third embodiment, only portions different from the first embodiment will be described, and common portions will be denoted by the same reference numerals in the drawings, and redundant description will be omitted.

FIG. 7A is a perspective view showing the optical path switching mirror 2 and the aperture plate 3 according to the third embodiment of the present invention.
FIG. 7B shows the optical path switching mirror 2 shown in FIG.
And aperture plate 3, light source 1 and optical fiber 4 for transmission original
FIG. 4 is a top view showing the positional relationship between the optical fiber and the reflection original optical fiber. As shown in FIG. 7, the illumination device according to the third embodiment has a triangular prism-shaped optical path switching mirror 2 attached to the surface of the diaphragm plate 3 opposite to the light source 1 to form an integral structure. Also, as shown in FIG. 7B, the optical path switching mirror 2
Is fixed so that the reflection surface 2b forms an angle of about 45 degrees with the incident direction of the illumination light. The aperture plate 3 is provided with an opening 3c for allowing illumination light to be incident on the reflection surface 2b of the optical path switching mirror 2. The opening 3c adjusts the light amount to an appropriate light amount when reading the reflection original. Then, when switching the optical path, the diaphragm plate 3 is driven to insert the optical path switching mirror 2 on the optical path of the light source 1. As a result, the optical path from the light source 1 passes through the opening 3c of the aperture plate 3 and is adjusted by the amount of light. I do.
In the third embodiment, since the optical path switching mirror 2 and the aperture plate 3 do not come into surface contact with each other, the optical path switching mirror 2 and the aperture plate 3 are integrally fixed via the bonding plate 3d.

Thus, the same effects as in the second embodiment can be obtained in the third embodiment. In addition, it is possible to obtain the optimal light amount for reading the reflection original by using the illumination light by the opening 3c. In the embodiment of the present invention, the optical path switching means is an optical path switching mirror. However, the optical path switching means is not limited to a mirror, and may be, for example, a triangular prism.

Although the light amount adjusting means is a diaphragm plate having a plurality of apertures, it is not limited to this form.
For example, a variable aperture of a plurality of blades used for a camera lens or the like is also applicable. In the present embodiment,
Although the illumination rod 6 for the transmission original and the illumination rod 7 for the reflection original have been described as one each, the present invention is not limited to this embodiment. For example, there are two illumination rods for the transmission original and two illumination rods for the reflection original. Alternatively, an illumination mode in which the original is illuminated from both sides of one line of the original, which is the illumination target portion, may be used.

[0034]

As described above, according to the image reading apparatus having the illumination device according to the first and third to eighth aspects of the present invention, the optical path of the illumination light from the light source is switched by the optical path switching means. Since the illumination light is selectively incident on one of the first light guide means and the second light guide means, the apparatus can be simplified.

According to the image reading apparatus having the illuminating device according to the second aspect of the present invention, by using a halogen lamp as the light source, it is possible to obtain a stable light source without uneven light quantity. Further, the lighting circuit of the light source can be a circuit system with less noise. Claims 9 to 1
According to the image reading apparatus having the illumination device according to the first aspect of the invention, the image reading device further includes a light amount adjustment unit for adjusting the light amount of the illumination light.
The amount of illumination light suitable for the density of the document can be obtained.

According to the image reading apparatus having the illuminating device according to the twelfth aspect of the present invention, since the light amount adjusting means has the light blocking portion for blocking the illuminating light, the fading of the original due to the illuminating light is prevented. it can. Further, according to the image reading apparatus having the illuminating device according to the thirteenth aspect, since the optical path switching means and the light amount adjusting means are integrally formed, the number of movable parts is reduced. Therefore, the device configuration can be further simplified.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a lighting device of an image input device according to a first embodiment of the present invention.

FIG. 2 is a top view illustrating a lighting device of the image input device according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing a mirror driving mechanism of the image input device according to the first embodiment of the present invention.

FIG. 4 is a front view showing an aperture plate driving mechanism of the image input device according to the first embodiment of the present invention.

FIG. 5 is an explanatory view showing the structure of a rod-type illumination system.

6A and 6B are diagrams illustrating examples of an optical path switching mirror and an aperture plate according to a second embodiment of the present invention. FIG. 6A is a perspective view, and FIG. 6B is a top view.

7A and 7B are diagrams illustrating examples of an optical path switching mirror and an aperture plate according to a third embodiment of the present invention, wherein FIG. 7A is a perspective view and FIG. 7B is a top view.

FIG. 8 is a diagram illustrating an example of a lighting device of a conventional image reading apparatus.

[Explanation of symbols]

 1: Halogen lamp 2: Optical path switching mirror 2b: Gear 3: Diaphragm plate 4: Optical fiber for transmission original 5: Optical fiber for reflection original 6: Illumination rod for transmission original 7: Illumination rod for reflection original 8a, 8b, 8c: Light shielding Walls 10, 35: Document 11: Mirror drive motor 11b: Drive gear 12: Aperture plate drive motor 12b: Drive gear 31a, 31b: Fluorescent tubes 33a, 33b: Fluorescent tube lighting circuit 35: Document 36: Mirror 37: Conclusion Image lens 38: CCD 41: Light source 42: Illumination rod 43: Diffusion plate

Claims (12)

[Claims] A light source that emits illumination light; a first light guide that guides the illumination light from the light source onto the document to illuminate the document; and a light source from the light source to illuminate the document. A second light guide for guiding illumination light onto the document; and an optical path of the illumination light emitted from the light source is switched to select the illumination light as one of the first light guide and the second light guide. An image reading apparatus having an illuminating device, comprising: 2. The image input device according to claim 1, wherein the light source is a halogen lamp. 3. The first light guide unit includes: a first transmission unit that transmits the illumination light; and a first illumination unit that illuminates the document by irradiating the illumination light from a side. The second light guide unit includes a second transmission unit that transmits the illumination light, and a second illumination unit that illuminates the document by irradiating the illumination light from a side surface, wherein the first transmission unit includes: One end is connected to the end of the first lighting unit, the other end is arranged on the optical path of the light source, and the second transmission unit has one end connected to the end of the second lighting unit, The image input device according to claim 1, wherein an end is disposed on an optical path of the light source. 4. The first lighting unit and the second lighting unit,
4. The image reading apparatus according to claim 3, wherein the image reading apparatus is provided at a position facing the document. 5. The optical path switching means comprises an optical member for refracting the illumination light, and is disposed on the optical path of the light source only when switching the optical path of the illumination light. An image reading device having the lighting device according to claim 1. 6. An image reading apparatus according to claim 5, wherein said optical path switching means is a mirror. 7. The image reading apparatus according to claim 5, wherein said optical path switching means is a prism. 8. The image reading apparatus according to claim 1, further comprising a light amount adjusting unit that adjusts a light amount of the illumination light emitted from the light source. 9. The image reading apparatus according to claim 8, wherein the light amount adjusting unit is disposed on an optical path between the light source and the optical path switching unit. 10. The image reading apparatus according to claim 8, wherein the light amount adjusting means is a plate member having a plurality of openings having different sizes. 11. An image reading apparatus according to claim 8, wherein said light amount adjusting means has a light shielding portion for shielding said illumination light. 12. The optical path switching means and the light quantity adjusting means are formed integrally.
An image reading device having the lighting device according to claim 1.