Image reading apparatus and image forming apparatus

An image reading apparatus, including point light sources, arranged in a straight line state, configured to output light to light a document, and a light leading member, positioned in front in a light outputting direction of the light output from the point light sources, configured to receive the light incident on a surface of the light leading member, and to lead the received light so as to irradiate along a main scanning direction toward the document. The light leading member includes a positioning unit configured to make a gap between one of the point light sources arranged in a line state and the light leading member the same as a gap between another of the point light sources and the light leading member, and to make an arrangement direction of the point light sources be positioned along a longitudinal direction of the light leading member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image reading apparatus having plural point light sources arranged in a straight line state and an image reading apparatus having the light reading apparatus.

2. Description of the Related Art

As an image reading apparatus used for an image forming apparatus such as a copying machine, one having a structure where plural LEDs (point light sources) lighting a document are arranged in a straight line state is known conventionally. See Japanese Patent Application Laid-Open Publication Nos. 07-162586 and 10-322521, for example. Furthermore, in a case where plural LEDs are used as light sources, in order to prevent the generation of illuminance ripple (unevenness of illumination distribution) in an arrangement direction of the LEDs at an object to be lighted, namely the document, a light leading member made of transparent resin, glass, or the like is arranged between the object to be lighted and the point light sources. The light leading member leads light irradiating from the point light sources and diffusing in a circle toward a surface of the document along a main scanning direction at the time when the document is read out, so that the light leading member can prevent the generation of the illuminance ripple.

However the inventions disclosed in the above-mentioned Japanese Patent Application Laid-Open Publications and others have a problem in that the surface of the document cannot be uniformly illuminated along the main scanning direction if a distance between the plural LEDs and the light leading member is not constant.

A state where the surface of the document is not being uniformly illuminated along the main scanning direction due to the distance between the LEDs and the light leading member not being constant is discussed with reference toFIG. 1throughFIG. 3. The lighting device of this optical reading apparatus, as shown inFIG. 1, includes an LED array substrate102and a light leading member103. In the LED array substrate102, plural LEDs (point light sources)100are arranged and fixed on a substrate101. The light leading member103is positioned in front of an outputting direction of light output from the LED100. The LED array substrate102and the light leading member103are attached to a housing member104.

The light output from the LEDs100is led by the light leading member103so as to be irradiated along the main scanning direction of the document D provided on a contact glass105. Reflection light from the document D is read out at a CCD (photoelectric conversion element) via a mirror106or lens (not shown) so that image information corresponding to the image of the document D can be obtained.

FIG. 2shows a case where a position relationship between the light leading member103and the LED array substrate102is shifted from a proper position. The direction of the shift causes the distance between the LEDs and the light leading member103to be not constant. In this case, an amount of light, incident on the light leading member103after the light is output from the LEDs100at the position where the distance between the light leading member103and the LED100is short is large. The amount of light, incident on the light leading member103after the light is output from the LEDs100at the position where the distance between the light leading member103and the LED100is long is small. Because of this, an amount of light, incident on the document D after the light is output from the light leading member103at a side where the distance between the light leading member103and the LED100is short is large. An amount of light incident on the document D after the lights is output from the light leading member103at a side where the distance between the light leading member103and the LED100is long is small. Arrows shown inFIG. 2show light beams incident on the document D and led by the light leading member103after the light beams are output from the corresponding LEDs100. A length of each arrow represents an amount of the irradiated light.

FIG. 3shows a case where a position relationship between the light leading member103and the LED array substrate102is shifted from a proper position.

A direction of the shift causes the arrangement direction of the LEDs100and the longitudinal direction of the light leading member103to be twisted. In this case, the light beams output from the LEDs arranged in the center of the arrangement direction are incident on the light leading part103, led by the light leading member103, and incident on the document D. However, the light beams output from the LEDs100positioned at both end sides in the arrangement direction are not incident in the light leading member103. The document D is not lighted at either end side in a longitudinal direction of the light leading member103.

SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to provide a novel and useful image reading apparatus and image forming apparatus.

Another and more specific object of the present invention is to provide an image reading apparatus and image forming apparatus whereby plural point light sources equally face the light leading member so that the document is uniformly irradiated along the main scanning direction by the light led by the light leading member after the light is output from the point light source.

The above object of the present invention is achieved by an image reading apparatus, including:

a plurality of point light sources, arranged in a straight line state, configured to output light for lighting a document situated on a contact glass from a lower side of the contact glass;

a light leading member, positioned in front in a light outputting direction of the light output from the point light sources, configured to lead the light output from the point light sources so as to irradiate along a main scanning direction toward the document situated on the contact glass; and

a photoelectric conversion element configured to receive reflection light from the document;

wherein the light leading member includes positioning-means configured to make a gap between each of the point light sources arranged in a line state and the light leading member constant and make an arrangement direction of the point light sources be positioned along a longitudinal direction of the light leading member.

According to the above-mentioned image reading apparatus, the lights beams from the point light sources are uniformly incident on the light leading member. It is possible to uniformly light the document along a main scanning direction of the document by the light that is led by the light leading member after being output from the point light source.

The image reading apparatus may further include:

a point light source array substrate where the point light sources are provided in the line state;

wherein the positioning means is formed by a holding part and a contact standard surface;

the holding part is provided in the light leading member;

the holding part has a mounting surface extending in parallel with the longitudinal direction of the light leading member, the mounting surface being where the point light source array substrate is mounted; and

the contact standard surface is formed in the light leading member and has a structure where a contact surface formed in the substrate contacts the contact standard surface by mounting the point light source array substrate on the mounting surface.

According to the above-mentioned image reading apparatus, by mounting the point light source array substrate on the mounting surface of the holding part, it is possible to makes an arrangement direction of the plural point light sources consistent with the longitudinal direction of the light leading member. In addition, by contacting the contact surface formed in the substrate with the contact standard surface of the light leading member, it is possible to make a gap between each of the point light sources and the light leading member31constant. Thus, the light beams from the point light sources are uniformly incident on the light leading member. It is possible to uniformly light the document along a main scanning direction of the document by the light that is led by the light leading member after being output from the point light source.

The image reading apparatus may further include:

a point light source array substrate where the point light sources are provided in the line state;

wherein the positioning means is formed by an insertion concave part and a contact standard surface;

the insertion concave part is provided in the light leading member and extends in parallel with the longitudinal direction of the light leading member; and

a contact surface formed in the substrate contacts the contact standard surface formed deep in the insertion concave part by inserting the substrate in the insertion concave part.

According to the above-mentioned invention, by inserting the substrate in the insertion concave part, it is possible to makes an arrangement direction of the plural point light sources consistent with the longitudinal direction of the light leading member. In addition, by contacting the contact surface formed in the substrate with the contact standard surface formed deep in the insertion concave part, it is possible to make a gap between each of the point light sources and the light leading member31constant. Thus, the light beams from the point light sources are uniformly incident on the light leading member. It is possible to uniformly light the document along a main scanning direction of the document by the light that is led by the light leading member after being output from the point light sources. Furthermore, a bend of the substrate can be corrected by inserting the substrate in the insertion concave part. Therefore, a gap between the point light source and the light leading member generated due to the bend of the substrate can be prevented. Therefore, lighting for the document can be further uniformly done along the main scanning direction of the document.

The image reading apparatus may further include:

a point light source array substrate where the point light sources are provided in the line state;

wherein the positioning means is formed by an insertion concave part and an incident surface of the light leading member;

the insertion concave part is provided in the light leading member and extends in parallel with the longitudinal direction of the light leading member; and

an emitting surface of each of the point light source contacts the incident surface by inserting the substrate in the insertion concave part.

According to the above-mentioned invention, by inserting the substrate in the insertion concave part, it is possible to makes an arrangement direction of the plural point light sources consistent with the longitudinal direction of the light leading member. In addition, by contacting the emitting surface of the point light sources with the incident surface of the light leading member, it is possible to make a gap between each of the point light sources and the light leading member31be constant. Thus, the light beams from the point light sources are uniformly incident on the light leading member. It is possible to uniformly light the document along a main scanning direction of the document by the light that is led by the light leading member after being output from the point light sources. Furthermore, a bend of the substrate can be corrected by inserting the substrate in the insertion concave part. Therefore, a gap between the point light sources and the light leading member generated due to the bend of the substrate can be prevented. Therefore, lighting for the document can be further uniformly done along the main scanning direction of the document.

The image reading apparatus may further include:

a point light source array substrate where the point light sources are provided in the line state;

wherein the positioning means is formed by a holding part and a plurality of installation screw holes;

the holding part is provided in the light leading member;

the holding part has a mounting surface extending in parallel with the longitudinal direction of the light leading member, the mounting surface being where the point light source array substrate is mounted; and

the installation screw holes are formed in the holding part, face a plurality of positioning holes formed in the substrate, and have a structure where fixing screws inserted in the positioning holes are screw-fixed with the installation screw holes, by mounting the point light source array substrate on the mounting surface.

According to the above-mentioned invention, by mounting the point light source array substrate on the mounting surface of the holding part, it is possible to make an arrangement direction of the plural point light sources consistent with the longitudinal direction of the light leading member. In addition, by facing the installation screw hole formed in the holding part toward the positioning hole formed in the substrate and fixing the fixing screw inserted in the positioning hole with the installation screw hole, it is possible to make a gap between each of the point light sources and the light leading member31constant. Thus, the light beams from the point light sources are uniformly incident on the light leading member. It is possible to uniformly light the document along a main scanning direction of the document by the light that is led by the light leading member after being output from the point light source.

One of a plurality of positioning holes, situated in the center part in the longitudinal direction in the substrate, may have a circular hole shaped configuration having a substantially same outside diameter as the fixing screw;

a length along the longitudinal direction in the substrate of the other positioning hole may be longer than a diameter of the fixing screw; and

the length along a direction perpendicular to the longitudinal direction in the substrate of the other positioning hole may be the substantially same as the diameter of the fixing screw.

According to the above-mentioned invention, even if a thermal expansion difference is generated between the holding part and the substrate depending on the change of the temperature, generation of a bend of the holding part or the substrate due to this thermal expansion difference can be prevented. Hence, a position gap between the point light sources and the light leading member based on the bend due to the thermal expansion difference can be prevented. Because of this, lighting for the document can be further uniformly done along the main scanning direction of the document.

The positioning means may be formed by a holding part and a wiring pattern;

the holding part may be provided in the light leading member;

the holding part may have a mounting surface extending in parallel with the longitudinal direction of the light leading member; and

the wiring pattern may be formed on the mounting surface and is connected to the point light source.

According to the above-mentioned invention, by forming the wiring pattern on the mounting surface provided in the light leading member and extending the wiring pattern in parallel with a longitudinal direction of the light leading member and by connecting the point light sources to the wiring pattern, it is possible to makes an arrangement direction of the plural point light sources consistent with the longitudinal direction of the light leading member and to make a gap between each of the point light sources and the light leading member31constant. Thus, the light beams from the point light sources are uniformly incident on the light leading member. It is possible to uniformly light the document along a main scanning direction of the document by the light that is led by the light leading member after being output from the point light source.

The image reading apparatus may further include:

a holding member having a plurality of press-fitting concave parts for the point light sources;

wherein the point light sources are press-fitted in the press-fitting concave parts;

the positioning means is formed by a holding part and a contact standard surface;

the holding part is provided in the light leading member and has a mounting surface extending in parallel with a longitudinal direction of the light leading member;

a wiring pattern is formed on the mounting surface; and

a contact surface formed in the holding member contacts the contact standard surface formed on the light leading member, by mounting the holding member wherein the point light source is light press fitted in the press-fitting concave part for the point light source, on the mounting surface so that the point light source is connected to the wiring pattern.

According to the above-mentioned invention, by mounting the holding member, wherein the point light source is light press fitted in the press-fitting concave part for the point light source, on the mounting surface so that the point light source is connected to the wiring pattern, it is possible to make an electrical connection to the point light source. Furthermore, it is possible to make an arrangement direction of the plural point light sources consistent with the longitudinal direction of the light leading member. In addition, by contacting the contact surface of the holding member with the contact standard surface of the light leading member, it is possible to make a gap between each of the point light sources and the light leading member constant. Thus, the light beams from the point light sources are uniformly incident on the light leading member. It is possible to uniformly light the document along a main scanning direction of the document by the light that is led by the light leading member after being output from the point light source. The point light sources are simply light-press fitted to the corresponding press-fitting concave parts for the point light sources of the holding member. Hence, if a certain point light source does not work, only the point light source which does not work is exchanged. Hence, it is not necessary to exchange the entirety of plural point light sources. It is also not necessary to exchange the entirety of plural point light sources including the light leading member. Hence, the maintenance when a point light source does not work can be implemented at low cost.

A press-fitting concave part for a peripheral circuit element where the peripheral circuit element is light-press-fitted may be formed in the holding part; and

the peripheral circuit element which is light-press-fitted in the press-fitting concave part for the peripheral circuit element may be connected to the wiring pattern.

According to the above-mentioned invention, it is possible to make an electrical connection between the point light source and the peripheral circuit element and therefore it is possible to achieve the same effect as the effect achieved by the invention claimed in claim8. Furthermore, since the peripheral circuit elements are simply light-press-fitted to the corresponding press-fitting concave parts of the holding member, if a certain peripheral circuit element does not work, only the peripheral circuit element which does not work is exchanged. Since only the wiring pattern61is formed on the mounting surface of the holding part, it is not necessary to solder-fix the peripheral circuit elements.

The holding member may be made of metal.

It is possible to improve transferability and radiation-ability of heat generated by the point light source and the peripheral circuit elements, so that it is possible to prevent the performance of the point light source and the peripheral circuit elements from degrading due to the influence of the heat.

The holding member may have a heat radiation part.

It is possible to improve radiation-ability of heat generated by the point light source and the peripheral circuit element, so that it is possible to prevent the performance of the point light source and the peripheral circuit element from degrading due to the influence of heat.

The image reading apparatus may further include:

a holding member having a plurality of press-fitting concave parts for the point light sources, the press-fitting concave parts being parts into which the point light sources are press-fitted; and

a substrate where a wiring pattern is formed;

wherein the positioning means is formed by a holding part and a positioning pin;

the holding part is provided in the light leading member and has a mounting surface extending in parallel with the longitudinal direction of the light leading member in a state where the substrate and the holding member are stacked;

the positioning pin is fixed to the-holding part so as to pierce the substrate and the holding member for position fixing; and

the substrate is mounted on the mounting surface, in a state where the point light source light-press-fitted in the press-fitting concave part is connected to the wiring pattern.

According to the above-mentioned invention, by mounting the holding member, wherein the point light sources are press-fitted in the press-fitting concave parts, and the substrate on the mounting surface of the holding part, it is possible to makes an arrangement direction of the plural point light sources consistent with the longitudinal direction of the light leading member. In addition, by position fixing the holding member mounted on the mounting surface and the substrate by the positioning pin fixed to the holding part, it is possible to make a gap between each of the point light sources and the light leading member31constant. Thus, the light beams from the point light sources are uniformly incident on the light leading member. It is possible to uniformly light the document along a main scanning direction of the document by the light that is led by the light leading member after being output from the point light sources. Furthermore, since the wiring pattern is formed on an exclusive substrate, a special process for forming the wiring pattern on the mounting surface of the holding part is not necessary so that productivity can be improved.

The positioning pin may be formed in a body with the holding part.

According to the above-mentioned invention, it is possible to improve positioning precision between the holding member and the holding part by the positioning pin. Because of this, it is possible to uniformly light the document along a main scanning direction of the document.

The above-mentioned object of the present invention is achieved by an image forming apparatus, including:

an image reading apparatus; and

a printer engine configured to form an image on a recording medium corresponding to image data read by the image reading apparatus;

wherein the image reading apparatus includes

a plurality of point light sources, arranged in a straight line state, configured to output light for lighting a document situated on a contact glass from a lower side of the contact glass;

a light leading member, positioned in front in a light outputting direction of the light output from the point light source, configured to lead the light output from the point light source so as to irradiate along a main scanning direction toward the document situated on the contact glass; and

a photoelectric conversion element configured to receive reflection light from the document;

wherein the light leading member includes positioning means configured to cause a gap between each of the point light sources arranged in a line state and the light leading member to be made constant and make an arrangement direction of the point light sources be positioned along the longitudinal direction of the light leading member.

According to the above-mentioned invention, it is possible to form the image corresponding to the stable image reading result by the image reading apparatus. Therefore, it is possible to improve the formed image quality.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description of the present invention and details of drawbacks of the related art are now given, with reference toFIG. 4throughFIG. 22, including embodiments of the present invention.

A first embodiment of the present invention is discussed with reference toFIG. 4throughFIG. 6.FIG. 4is a schematic front view of an internal structure of a full-color copying machine1of a first embodiment of the present invention.FIG. 5is a perspective view of a structure of a lighting device.FIG. 6is a longitudinal sectional view of the lighting device18.

A printer engine3for forming a color image is provided in a central part in an apparatus body2of the copying machine1. This printer engine3includes: four drum-like photosensitive members4that are arranged in parallel horizontally to be spaced apart at an equal interval; charging rollers5that form toner images on outer peripheral surfaces of the photosensitive members4; an exposing device6that exposes the uniformly charged outer peripheral surfaces of the photosensitive members4to a laser beam according to image data to thereby form electrostatic latent images on the outer peripheral surfaces; developing devices7that supply toner to the electrostatic latent images so as to change the electrostatic latent images to toner images; an intermediate transfer belt8on which toner images formed on the outer peripheral surfaces of the respective photosensitive members4are sequentially transferred; cleaning devices9that removes the toner remaining on the photosensitive members4after the toner images are transferred onto the intermediate transfer belt8; a transfer roller10that transfers the toner image on the intermediate transfer belt8onto a recording medium S, and others. Toner images of Y (yellow), M (magenta), C (cyan), and B (black) are formed in the four photosensitive members4, respectively. The toner images of these colors are respectively transferred onto the intermediate transfer belt8in turn so that a color toner images is formed on the intermediate transfer belt8and the color toner image is transferred to the recording medium S.

An ADF (automatic document feeder)11, which automatically feeds a document D that is the object to be lighted by the lighting device18, a contact glass12where the document D is provided, and an image reading apparatus13which reads the document automatically fed by the ADF11or the document placed on the contact glass12, are arranged above the apparatus body12.

The image reading apparatus13includes: first and second traveling bodies14and15that are capable of traveling at speeds in the ratio of 2:1 in parallel with the contact glass12; a lens16; and a CCD17serving as a photoelectric conversion element. The first traveling body14is equipped with a lighting device18for lighting a surface of the document D placed on the contact glass12or the document conveyed by the ADF11and a first mirror19that reflects light reflected on the surface of the document D and traveling along a reading optical axis. The second traveling body15is mounted with a second mirror20and a third mirror21that further reflect the light reflected by the first mirror19. The lens16and the CCD17are arranged in a traveling direction of the reading light sequentially reflected by the first through third mirrors19,20, and21. The CCD17receives a reflection light (reading light) reflected by the document D after the light is output from the lighting device18to the document D.

Sheet cassettes22of plural stages, for example, four stages, in which recording media S are stored, are provided below the apparatus body2. The recording media S stored in these sheet cassettes22are separated and fed one by one by pickup rollers23and feed rollers24. The separated and fed sheets are conveyed along a sheet conveying path25provided in the apparatus body2. A registration roller26, the transfer roller10, a fixing device27, a discharge roller28, and the like are arranged along this sheet conveying path25.

Depending on the conveyance timing and timing for image-forming on the intermediate transfer belt8, the registration roller26is intermittently rotated. By stopping the rotation of the registration roller26, the recording medium conveyed to the sheet conveying path25is stopped for a while and the recording medium S is sent out by rotating the registration roller26. The recording medium S sent out by the rotation of the registration roller26is conveyed to a transferring position that is put between the intermediate transfer belt8and the transfer roller10.

The fixing device27applies heat and pressure to the recording medium S where the toner image is transferred so that the toner is melted. As a result of this, the toner image is fixed to the recording medium S.

Under this structure, an action for forming an image in the copying machine1is done as follows. First, forming of the toner image is started at the printer engine3. At the time when the toner image is formed, first of all, the image of the document D placed on the contact glass12or automatically conveyed by the ADF11is read out by the image reading apparatus13. In such a structure, laser beams corresponding to image data of respective colors (yellow Y, magenta M, cyan C, and black B) are emitted from semiconductor lasers of the exposing device6according to a result of reading by the image reading apparatus13. The laser beams expose the outer peripheral surfaces of the respective photosensitive members4that are uniformly charged by the charging rollers5, whereby electrostatic latent images are formed. Toners of the respective colors are supplied to the electrostatic latent images from the respective developing devices7, whereby toner images of the respective colors are formed. The toner images on the respective photosensitive members4are sequentially transferred onto the intermediate transfer belt8, which moves in synchronization with the photosensitive members4, and a color toner image is formed on the intermediate transfer belt8.

On the other hand, the recording medium S is started to be separated and fed from the inside of the sheet cassettes22before or after the start of the image forming operation in the printer engine. The recording medium S separated, fed, and conveyed through the sheet conveying path25is timed by the registration roller26that is driven to rotate intermittently so as to be sent to a transferring position between the intermediate transfer belt8and the transferring roller10.

When the recording medium S is sent to the transferring position between the intermediate transfer belt8and the transfer roller10, the color toner image on the intermediate transfer belt8is transferred onto the recording medium S. The recording medium S where the color toner image is transferred is conveyed on the sheet conveyance path25so that the color toner image is fixed on the recording medium S in a course of passing through the fixing device27. The recording medium S having the color toner image fixed thereon is discharged onto a discharge tray29by the discharge roller28.

Under this structure, the lighting device of this embodiment, as shown inFIG. 5andFIG. 6, includes an LED array substrate30that is a point light source array substrate and a light leading member31. The LED array substrate30includes a substrate33and plural LEDs32as light sources. The LEDs32are arranged and fixed in a straight line state at a designated equal pitch on the substrate33having a liner configuration. The LEDs32are arranged in a longitudinal direction of the substrate33. This arrangement direction is consistent with a main scanning direction of the document D at the time when an image is read in a case where the lighting device18is installed in the image reading apparatus13. In addition, a wiring pattern (not shown) where the fixed LEDs32are electrically connected is formed in the substrate33. Furthermore, in this LED array substrate30, a periphery circuit element (not shown) including an electric current limiting register is connected and fixed to the wiring pattern. Although a case where one line of the LEDs32is provided in the straight line state is discussed in this embodiment as an example, LEDs of plural lines along the direction consistent with the main scanning direction of the document D may be provided at the time when the image is read.

The light leading member31is made of transparent resin such as acrylic or polycarbonate, glass, or the like. The light leading member31is positioned in front of the outputting direction of the light output from the LEDs32to the document D. The light leading member31includes an incident surface31aand outputting surface31b. The light output from the LEDs32is incident on the incident surface31a. The incident light is output toward the document D along the main scanning direction of the document D via the outputting surface31b. The light leading member31has a linear configuration and extends along the arrangement direction of the LEDs32.

A holding part34is formed in a body at a side of the incident surface31aof the light leading member31. The holding part34holds the LED array substrate30and extends along a longitudinal direction of the light leading member31. In the holding part34, a mounting surface is formed so as to be parallel to a longitudinal direction of the light leading member31and orthogonal to the incident surface31a. The LED array substrate30is attached to the holding part34in a direction in which a bottom surface of the substrate33is mounted on the mounting surface34a. The bottom surface of the substrate33and the mounting surface34aare adhered by an adhesive or stuck by double-sided tape to each other, so that the LED array substrate30is fixed to the holding part34.

An area which is a part of the incident surface31aof the light leading member31and is adjacent to the mounting surface34aworks as a contact standard surface35. A surface which is along a longitudinal direction of the substrate33and faces the contact standard surface35when the LED array substrate30is mounted on the mounting surface34ais a contact surface36, which contacts the contact standard surface35. A positioning member37is formed in the light leading member31. The positioning member37makes a gap between each of the LEDs32arranged in a line state and the light leading member31constant by the holding part34having the mounting surface34aand the contact standard surface35. The positioning member37also makes an arrangement direction of the LEDs32to be positioned along the longitudinal direction of the light leading member31.

Under this structure, as shown inFIG. 5andFIG. 6, the LED array substrate30is mounted on the mounting surface34aof the holding part34and fixed to the holding part34by the adhesive or the double-sided tape. The bottom surface of the substrate33is mounted on the mounting surface34aand the contact surface36of the substrate33contacts the contact standard surface35of the light leading member31.

The mounting surface34ais a surface extending in parallel with the longitudinal direction of the light leading member31. Thus, by mounting the LED array substrate30on the mounting surface34a, it is possible to position plural LEDs32and the light leading member31so that the arrangement direction of the LEDs32is consistent with the longitudinal direction of the light leading member31. In addition, by contacting the contact surface of the substrate33with the contact standard surface35of the light leading member31, it is possible for the gap between each of the LEDs32and the incident surface31aof the light leading member31to be made constant. Because of this, the light beams from the LEDs32are incident on the incident surface31aof the light leading member31. It is possible to uniformly light the document D along a main scanning direction of the document D by the light that is led by the light leading member31after being output from the LEDs32and then output from the outputting surface31b. Because of this, a light receiving property of a light received by a CCD17is improved and therefore it is possible to improve the quality of an image formed by the printer engine3based on a result of reading by the image reading apparatus13.

In this embodiment, it is preferable that a fixing position of the LED array substrate30be positioned so that the LEDs32face the incident surface31aat a substantially center position of a width “A” in a direction perpendicular to the longitudinal direction of the outputting surface31bof the light leading member31, namely a sub-scanning direction at the time of image reading.

Although the holding part34is uniformly formed with the light leading member31in this embodiment, the present invention is not limited to this. For example, the holding part34may be formed separately from the light leading member31and this holding part34may be fixed to the light leading member31.

Next, the second embodiment of the present invention is discussed with reference toFIG. 7andFIG. 8. InFIG. 7andFIG. 8, parts that are the same as the parts discussed above are given the same reference numerals, and explanation thereof is omitted.FIG. 7is a perspective view showing a structure of the lighting device of the second embodiment of the present invention.FIG. 8is a longitudinal sectional view of the lighting device shown inFIG. 7.

In this embodiment, a lighting device40is provided for lighting the document D situated on the contact glass12from a lower side of the contact glass12. The image reading apparatus13(SeeFIG. 4) is formed by the lighting device40and the CCD17(SeeFIG. 4) reading a reflection light (reading light) reflected by the document D after the light output from the lighting device40is irradiated on the document D.

The lighting device40includes the LED array substrate30and the light leading member31. The LED array substrate30includes plural LEDs32. The LEDs32are arranged and fixed in a straight line state at a designated equal pitch on the substrate33having a liner configuration. The LEDs32are arranged in a longitudinal direction of the substrate33. This arrangement direction is consistent with a main scanning direction of the document D at the time when an image is read in a case where the lighting device40is installed in the image reading apparatus13.

The light leading member31is made of transparent resin such as acrylic or polycarbonate, glass, or the like. The light leading member31is positioned in front of the outputting direction of the light output from the LEDs32to the document D. The light leading member31includes an incident surface31aand outputting surface31b. The light output from the LEDs32is incident on the incident surface31a. The incident light is output toward the document D along the main scanning direction of the document D via the outputting surface31b. The light leading member31has a linear configuration and extends along the arrangement direction of the LEDs32.

The holding part34is formed in a body at the side of the incident surface31aof the light leading member31. The holding part34holds the LED array substrate30and extends along the longitudinal direction of the light leading member31. In the holding part34, the mounting surface is formed so as to be in parallel with the longitudinal direction of the light leading member31and orthogonal to the incident surface31a. The LED array substrate30is attached to the holding part34in the direction in which a bottom surface of the substrate33is mounted on the mounting surface34a. SeeFIG. 5.

A bottom surface forming a single surface with the mounting surface34ais formed at a side of the incident surface31aof the light leading member31. An insertion concave part is formed at the side of the incident surface31aof the light leading member31so as to extend in parallel with the longitudinal direction of the light leading member31. A height “B” of the insertion concave part41is slightly greater than the thickness of the substrate33. One side along the longitudinal direction of the substrate33is inserted into the insertion concave part41so that the LED array substrate30is fixed to the light leading member31.

A surface deep in the insertion concave part41works as a contact standard surface42and extends in parallel with the longitudinal direction of the light leading member31. A surface which is along a longitudinal direction in the substrate33and which is inserted in the insertion concave part41is a contact surface43, which is made to contact the contact standard surface42by inserting the substrate33in the insertion concave part41. A positioning member44makes a gap between each of the LEDs32arranged in a line state and the light leading member31constant by contact between the insertion concave part41and the contact standard surface42. The positioning member44also causes an arrangement direction of the LEDs32position to be along the longitudinal direction of the light leading member31.

Under this structure, as shown inFIG. 7andFIG. 8, the LED array substrate30is fixed to the light leading part31by inserting the substrate33in the insertion concave part41so that the contact surface43of the substrate33contacts the contact standard surface42formed deep in the insertion concave part41. The bottom surface of the substrate33contacts the mounting surface34aof the holding part34.

The insertion concave part41extends in parallel with the longitudinal direction of the light leading member31. Hence, by inserting the substrate33of the LED array substrate30in the insertion concave part41, it is possible to position plural LEDs32and the light leading member31so that the arrangement direction of the LEDs32is consistent with the longitudinal direction of the light leading member31. In addition, by contacting the contact surface43of the substrate33with the contact standard surface42formed deep in the insertion concave part41, it is possible for the gap between each of the LEDs32and the incident surface31aof the light leading member31to be made constant. Because of this, the light beams from the LEDs32are uniformly incident on the incident surface31aof the light leading member31. It is possible to uniformly light the document D along a main scanning direction of the document D by the light that is led by the light leading member31after being output from the LED32and then output from the outputting surface31b. Because of this, a light receiving property of a light received by a CCD17is improved and therefore it is possible to improve the quality of an image formed by the printer engine3based on a result of reading by the image reading apparatus13.

Furthermore, according to this embodiment, a bend of the substrate33can be corrected by inserting the substrate33in the insertion concave part41. Therefore, a gap between the LEDs32and the light leading member31generated due to the bend of the substrate33can be prevented. Therefore, lighting for the document D can be further uniformly done along the main scanning direction of the document D.

Next, the third embodiment of the present invention is discussed with reference toFIG. 9andFIG. 10.FIG. 9is a perspective view showing a structure of the lighting device of the third embodiment of the present invention.FIG. 10is a longitudinal sectional view of the lighting device shown inFIG. 9.

In this embodiment, a lighting device50is provided for lighting the document D situated on the contact glass12from a lower side of the contact glass12. The image reading apparatus13(SeeFIG. 4) is formed by the lighting device50and the CCD17(SeeFIG. 4) reading a reflection light (reading light) reflected by the document D after the light output from the lighting device50is irradiated on the document D.

The lighting device50includes the LED array substrate30and the light leading member31. The LED array substrate30includes plural LEDs32. The LEDs32are arranged and fixed in a straight line state at a designated equal pitch on the substrate33having a linear configuration. The LEDs32are arranged in a longitudinal direction of the substrate33. This arrangement direction is consistent with a main scanning direction of the document D at the time when image is read in a case where the lighting device50is installed in the image reading apparatus13.

The light leading member31includes an incident surface31aand outputting surface31b. The light leading member31has a linear configuration and extends along the arrangement direction of the LEDs32. The holding part34and the insertion concave part41are formed in the light leading member31. A height “B” of the insertion concave part41is slightly greater than the thickness of the substrate33. One side along the longitudinal direction of the substrate33is inserted in the insertion concave part41so that the LED array substrate30is fixed to the light leading member31.

By inserting the substrate33in the insertion concave part41so that the LED array substrate30is fixed to the light leading member31, an emission surface32aof the LED32contacts the incident surface31aof the light leading member31positioned at an entrance side edge part of the insertion concave part41. A positioning member51makes a gap between each of the LEDs32arranged in a line state and the light leading member31constant by the insertion concave part41and the incident surface31apositioned at the entrance side edge part of the insertion concave part41. The positioning member44also makes an arrangement direction of the LEDs32to be positioned along the longitudinal direction of the light leading member31.

Under this structure, as shown inFIG. 9andFIG. 10, the LED array substrate30is fixed to the light leading part31by inserting the substrate33in the insertion concave part41so that the emission surface32aof the LED32contacts the incident surface31aof the light leading member31positioned at the entrance side edge part of the insertion concave part41. The bottom surface of the substrate33contacts the mounting surface34aof the holding part34.

The insertion concave part41extends in parallel with the longitudinal direction of the light leading member31. Hence, by inserting the substrate33of the LED array substrate30in the insertion concave part41, it is possible to position plural LEDs32and the light leading member31so that the arrangement direction of the LEDs32is consistent with the longitudinal direction of the light leading member31. In addition, by contacting the emission surface32aof the LED32with the incident surface31aof the light leading member31, it is possible to make the gap between each of the emission surface32aof the LEDs32and the incident surface31aof the light leading member31constant (a length of the gap is “0”). Because of this, the light beams from the LEDs32are uniformly incident on the light leading member31. It is possible to uniformly light the document D along a main scanning direction of the document D by the light that is led by the light leading member31after being output from the LED32and then output from the outputting surface31b. Because of this, a light receiving property of a light received by a CCD17is improved and therefore it is possible to improve the quality of an image formed by the printer engine3based on a result of reading by the image reading apparatus13.

Furthermore, according to this embodiment, a bend of the substrate33can be corrected by inserting the substrate33in the insertion concave part41. Therefore, a gap between the LEDs32and the light leading member31generated due to the bend of the substrate33can be prevented. Therefore, lighting for the document D can be further uniformly done along the main scanning direction of the document D.

Next, the fourth embodiment of the present invention is discussed with reference toFIG. 11throughFIG. 13.FIG. 11is a perspective view showing a structure of the lighting device of the fourth embodiment of the present invention.FIG. 12is a longitudinal sectional view of a part of positioning means.FIG. 13is a longitudinal sectional view of another part of the positioning means.

In this embodiment, a lighting device55is provided for lighting the document D situated on the contact glass12from a lower side of the contact glass12. The image reading apparatus13(SeeFIG. 4) is formed by the lighting device55and the CCD17(SeeFIG. 4) reading a reflection light (reading light) reflected by the document D after the light output from the lighting device55is irradiated on the document D.

The lighting device55includes the LED array substrate30and the light leading member31. The LED array substrate30includes plural LEDs32. The LEDs32are arranged and fixed in a straight line state at a designated equal pitch at the substrate33having a linear configuration. The LEDs32are arranged in a longitudinal direction of the substrate33. This arrangement direction is consistent with a main scanning direction of the document D at the time when an image is read in a case where the lighting device55is installed in the image reading apparatus13.

A holding part34is formed in a body at a side of the incident surface31aof the light leading member31. The holding part34holds the LED array substrate30and extends along a longitudinal direction of the light leading member31. In the holding part34, a mounting surface34ais formed so as to be in parallel with a longitudinal direction of the light leading member31and orthogonal to the incident surface31a. The LED array substrate30is attached to the holding part34in a direction so that a bottom surface of the substrate33is mounted on the mounting surface34a.

Plural installation screw holes56are formed in the holding part34along the longitudinal direction of the light leading member31. Plural positioning holes57(57aand57b) are formed in the substrate33so as to face the installation screw holes56by holding the LED array substrate30to contact the holding part34. The LED array substrate30is mounted on the mounting surface34a.Positions of the positioning holes57and the installation screw holes56are adjusted in upper and lower directions. Then, fixing screws58inserted in the positioning holes57is screw-fixed to the corresponding installation screw holes56so that the LED array substrate30is fixed to the holding part34.

A positioning member51causes a gap between each of the LEDs32arranged in a line state and the light leading member31to be constant by the holding part34having the mounting surface34aand the installation screw holes56into which the fixing screws58are inserted and screw-fixed. The positioning member51also makes an arrangement direction of the LEDs32to be positioned along the longitudinal direction of the light leading member31.

A single positioning hole57a, situated in the center part in the longitudinal direction in the substrate33, among plural positioning holes57(57aand57b) has a circular hole shaped configuration having a substantially same outside diameter as the fixing screw58. The length along the longitudinal direction in the substrate33of other positioning holes57bis longer (elongated) than the diameter of the fixing screw58. The length along a direction perpendicular to the longitudinal direction in the substrate33of other positioning holes57bis the substantially the same as the diameter of the fixing screw58.

Under this structure, as shown inFIG. 11, the LED array substrate30is mounted on the mounting surface34aof the holding part34. Positions of the positioning holes57and the corresponding installation screw holes56face each other. Then, the fixing screws58inserted in the positioning holes57are screw-fixed to the installation screw holes56so that the LED array substrate30is fixed to the holding part34.

The mounting surface34aextends in parallel with the longitudinal direction of the light leading member31. Hence, by mounting the LED array substrate30on the mounting surface34a,it is possible to position plural LEDs32and the light leading member31so that the arrangement direction of the LEDs32is consistent with the longitudinal direction of the light leading member31. In addition, by facing the installation screw holes56formed in the holding part34to the positioning holes57formed in the substrate33and screw-fixing the fixing screws58, inserted in the positioning holes57, into the corresponding installation screw holes56, it is possible to cause the gap between each of the emission surface of the LEDs32and the incident surface31aof the light leading member31to be made constant. Because of this, the light beams from the LEDs32are uniformly incident on the light leading member31. It is possible to uniformly light the document D along a main scanning direction of the document D by the light that is led by the light leading member31after being output from the LEDs32and then output from the outputting surface31b. Because of this, a light receiving property of light received by a CCD17is improved and therefore it is possible to improve the quality of an image formed by the printer engine3based on a result of reading by the image reading apparatus13.

In this embodiment, a single positioning hole57a, situated in the center part in the longitudinal direction in the substrate33has a circular hole shaped configuration having a substantially same outside diameter as the fixing screw58. The length along the longitudinal direction in the substrate33of other positioning hole57bis longer than the diameter of the fixing screw58. The length along a direction perpendicular to the longitudinal direction in the substrate33of the other positioning hole57bis substantially the same as the diameter of the fixing screw58. Therefore, even if a thermal expansion difference (a thermal expansion difference in the direction along the longitudinal direction of the substrate33and the holding part34) is generated between the holding part34and the substrate33due to a change of temperature, this thermal expansion difference can be accommodated by a gap between the internal circumferential surface of each of the positioning holes57band an external circumferential surface of the corresponding fixing screw58, namely a gap existing along the longitudinal direction of the substrate33and the holding part34. Hence, the generation of a bend of the holding part34or the substrate33due to the thermal expansion difference between the holding part34and the substrate33can be prevented. Hence, a position gap between the LEDs32and the light leading member31based on a bend due to thermal expansion difference can be prevented. Because of this, lighting for the document D can be further uniformly done along the main scanning direction of the document D.

It is preferable to form a fine gap G (SeeFIG. 13) between a head part of the fixing screw58being inserted in the positioning screw hole57band an upper surface of the substrate33. The fine gap G accommodates a relative movement of the fixing screw58and the substrate33when a thermal expansion difference is generated.

Next, the fifth embodiment of the present invention is discussed with reference toFIG. 14andFIG. 15.FIG. 14is a perspective view showing a structure of the lighting device of the fifth embodiment of the present invention.FIG. 15is a longitudinal sectional view of the structure of the lighting device.

In this embodiment, a lighting device60is provided for lighting the document D situated on the contact glass12from a lower side of the contact glass12. The image reading apparatus13(SeeFIG. 4) is formed by the lighting device60and the CCD17(SeeFIG. 4) reading a reflection light (reading light) reflected by the document D after the light is output from the lighting device60is irradiated on the document D.

The lighting device60includes plural LEDs32and the light leading member31. A holding part34is formed in a body at a side of the incident surface31aof the light leading member31. The holding part34extends along a longitudinal direction of the light leading member31. In the holding part34, a mounting surface34ais formed so as to be in parallel with a longitudinal direction of the light leading member31and orthogonal to the incident surface31a.

A wiring pattern61is formed on the mounting surface34aof the holding part34. Plural LEDs32and plural peripheral circuit elements62such as an electric current limiting resistance are connected to the wiring pattern61. The LEDs32and the peripheral circuit elements62are positioned at designated positions on the wiring pattern61and solder-fixed so as to be mounted on the holding part34.

A positioning member63makes a gap between each of the LEDs32arranged in a line state and the light leading member31constant by the holding part34having the mounting surface34aand the wiring pattern61which is formed on the mounting surface34aand to which the LEDs32and the peripheral circuit elements62are connected. The positioning member63also makes an arrangement direction of the LEDs32to be positioned along the longitudinal direction of the light leading member31.

Under this structure, in this embodiment, the wiring pattern61is formed in the holding part34which is formed uniformly with the light leading member31. The LEDs32and the peripheral circuit elements62connected to the wiring pattern61are mounted on the holding part34.

The wiring pattern61is formed on the mounting surface34aof the holding part34formed uniformly with the light leading member31and extending in parallel with the longitudinal direction of the light leading member31. By connecting the plural LEDs32to the wiring pattern61, it is possible to position plural LEDs32and the light leading member31so that the arrangement direction of the LEDs32is consistent with the longitudinal direction of the light leading member31. In addition, it is possible to cause the gap between each of the emission surface of the LEDs32and the incident surface31aof the light leading member31to be made constant. Because of this, the light beams from the LEDs32are uniformly incident on the light leading member31. It is possible to uniformly light the document D along a main scanning direction of the document D by the light that is led by the light leading member31after being output from the LED32and then output from the outputting surface31b. Because of this, a light receiving property of light received by a CCD17is improved and therefore it is possible to improve the quality of an image formed by the printer engine3based on a result of reading by the image reading apparatus13.

Next, the sixth embodiment of the present invention is discussed with reference toFIG. 16andFIG. 17.FIG. 16is an exploded perspective view showing a structure of the lighting device of the sixth embodiment of the present invention.FIG. 17is a longitudinal sectional view of the lighting device shown inFIG. 16.

In this embodiment, a lighting device65is provided for lighting the document D situated on the contact glass12from a lower side of the contact glass12. The image reading apparatus13(SeeFIG. 4) is formed by the lighting device65and the CCD17(SeeFIG. 4) reading a reflection light (reading light) reflected by the document D after the light output from the lighting device65is irradiated on the document D.

The lighting device65includes plural LEDs32, the light leading member31, and a holding member66holding the LEDs32. A holding part34is formed in a body at a side of the incident surface31aof the light leading member31. The holding part34extends along a longitudinal direction of the light leading member31. In the holding part34, a mounting surface34ais formed so as to be in parallel with a longitudinal direction of the light leading member31and orthogonal to the incident surface31a.

A wiring pattern61is formed on the mounting surface34aof the holding part34. Plural peripheral circuit elements62such as an electric current limiting resistance are connected to the wiring pattern61. The peripheral circuit elements62are positioned at designated position on the wiring pattern61and solder-fixed so as to be mounted on the holding part34. Plural screw holes67are formed at positions in the holding part34along the longitudinal direction of the holding part34.

Plural press-fitting concave parts68for the point light sources, plural screw insertion holes69, and plural escaping holes70are formed in the holding member66. The press-fitting concave parts68for the point light sources, screw insertion holes69, and escaping holes70are arranged in a straight line state along the longitudinal direction of the holding member66. The LEDs32are light-press-fitted into the press-fitting concave parts68for the point light sources. The peripheral circuit elements62fit in the escaping holes70by fixing the holding member66to the holding part34. The holding member66light-press-fits the LEDs32into the press-fitting concave parts68for the point light sources, which makes the LED32face the electrical connection position over the wiring pattern61, and makes the screw insertion holes69face the corresponding screw holes67, so as to be mounted on the mounting surface34aof the holding part34. The holding member66is fixed to the holding part34by screw-fixing the fixing screw71inserted in the screw insertion hole69with the screw holes67. The LEDs32are pressed and connected at the designated position on the wiring pattern61by the above-discussed fixing. The arrangement direction of the press-fitting concave parts68for the point light sources is consistent with the main scanning direction of the document D at the time when the image is read in a case where the lighting device65is installed in the image reading apparatus13.

An area which is a part of the incident surface31aof the light leading member31and is adjacent to the mounting surface34aworks as a contact standard surface72. A surface which is along a longitudinal direction in the holding member66and faces the contact standard surface35by mounting the holding member66on the holding part34is a contact surface73which contacts the contact standard surface72. A positioning member74is formed in the light leading member31. The positioning member74makes a gap between each of the LEDs32arranged in a line state and the light leading member31constant by the holding part34having the mounting surface34aon which the wiring pattern61is formed and the contact standard surface72. The positioning member37also makes an arrangement direction of the LEDs32be positioned along the longitudinal direction of the light leading member31.

The holding member66is made of metal such as aluminum, copper, an aluminum alloy, or a copper alloy. By using a die-casting method, an extrusion method, or a sintering method, for example, as a method for forming the holding member66made of metal, it is possible to easily form the holding member66having a large number of small press-fitting concave parts68for the point light sources and escaping holes70.

Under this structure, the holding member66holding the LEDs32is fixed to the holding part34where the wiring pattern61is formed by using the fixing screws71so that the LEDs32are pressed and connected to the wiring pattern61formed on the mounting surface34aof the holding part34. Because of this, it is possible to electrically connect the LEDs32.

The mounting surface34aextends in parallel with the longitudinal direction of the light leading member31. Hence, by mounting the holding member66light-press-fitting the LEDs32to the press-fitting concave parts68for the point light sources on the mounting surface34a, it is possible to position plural LEDs32and the light leading member31so that the arrangement direction of the LEDs32is consistent with the longitudinal direction of the light leading member31. In addition, by contacting the contact surface73of the holding member66with the contact standard surface72of the light leading member31, it is possible to cause the gap between each of the LEDs32and the incident surface31aof the light leading member31to be made constant. Because of this, the light beams from the LEDs32are uniformly incident on the incident surface31aof the light leading member31. It is possible to uniformly light the document D along a main scanning direction of the document D by the light that is led by the light leading member31after being output from the LED32and then output from the outputting surface31b. Because of this, a light receiving property of a light received by a CCD17is improved and therefore it is possible to improve the quality of an image formed by the printer engine3based on a result of reading by the image reading apparatus13.

Furthermore, according to this embodiment, the LED32is simply light-press fitted to the press-fitting concave parts68for the point light sources of the holding member66. Hence, if a certain LED32does not work, only the LED32which does not work is exchanged. Hence, it is not necessary to exchange the entirety of plural LEDs32. It is also not necessary to exchange the entirety of plural LEDs32including the light leading member31. Hence, the maintenance when an LED32does not work can be implemented at low cost.

In addition, in the case where the holding member66is made of metal, it is possible to improve transferability and radiation-ability of heat generated by the LED32and the peripheral circuit element62, so that it is possible to prevent the performance of the LEDs32and the peripheral circuit element62from degrading due to the influence of the heat.

In this embodiment, as well as the single positioning hole57aof the fourth embodiment of the present invention (SeeFIG. 11throughFIG. 13), the screw insertion hole69, situated in the center part in the longitudinal direction of the holding member66has a circular hole shaped configuration having a substantially same outside diameter as the fixing screw71. The length along the longitudinal direction in the holding member66of other screw insertion hole69may be longer (elongated) than the diameter of the fixing screw71. In this case, even if a thermal expansion difference (a thermal expansion difference in the direction along the longitudinal direction of the holding part34and the holding member66) is generated between the holding part34and the holding member66depending on the change of the temperature, a generation of a bend of the holding part34or the holding member66due to the thermal expansion difference can be prevented. Hence, a position gap between the LEDs32and the light leading member31based on the bend due to a thermal expansion difference can be prevented. Because of this, lighting for the document D can be further uniformly done along the main scanning direction of the document D.

Next, the seventh embodiment of the present invention is discussed with reference toFIG. 18andFIG. 19.FIG. 18is an exploded perspective view showing a structure of the lighting device of the seventh embodiment of the present invention.FIG. 19is a longitudinal sectional view of the lighting device shown inFIG. 18.

In this embodiment, a lighting device75is provided for lighting the document D situated on the contact glass12from a lower side of the contact glass12. The image reading apparatus13(SeeFIG. 4) is formed by the lighting device75and the CCD17(SeeFIG. 4) reading a reflection light (reading light) reflected by the document D after the light output from the lighting device75is irradiated on the document D.

A basic structure of the lighting device75is the same as the lighting device65of the sixth embodiment of the present invention. A different point of the lighting device75from the lighting device65is that plural press-fitting concave parts76for peripheral circuit elements, in addition to plural press-fitting concave parts68for the point light sources, are formed in the holding member66of the lighting device75. The LEDs32are light-press-fitted into the press-fitting concave parts68for the point light sources and the peripheral circuit elements62such as the electric current limiting resistance are light-press-fitted into the press-fitting concave parts76for peripheral circuit elements. Because of this, the elements62are not solder-fixed to the wiring pattern61formed on the mounting surface34aof the holding part34.

In this embodiment, as well as the sixth embodiment, the positioning part74is formed by the holding part34having the mounting surface on which the wiring pattern61is formed and the contact standard surface72.

Under this structure, the holding member66holding the LEDs32and the peripheral circuit elements62is fixed to the holding part34where the wiring pattern61is formed on the mounting surface34a, by using the fixing screws71, so that the LEDs32and the peripheral circuit elements62are pressed and connected to the wiring pattern61. Because of this, it is possible to electrically connect the LEDs32.

The mounting surface34aextends in parallel with the longitudinal direction of the light leading member31. Hence, by mounting the holding member66light-press-fitting the LEDs32into the press-fitting concave parts68for the point light sources on the mounting surface34a, it is possible to position plural LEDs32and the light leading member31so that the arrangement direction of the LEDs32is consistent with the longitudinal direction of the light leading member31. In addition, by contacting the contact surface73of the holding member66with the contact standard surface72of the light leading member31, it is possible to cause the gap between each of the LEDs32and the incident surface31aof the light leading member31to be made constant. Because of this, the light beams from the LEDs32are uniformly incident on the incident surface31aof the light leading member31.

In addition, according to this embodiment, only the wiring pattern61is formed on the mounting surface of the holding part34. It is not necessary to solder-fix the elements connected to the wiring pattern61and therefore it is possible to reduce the number of working processes. Furthermore, it is possible to eliminate the influence of heat on the light leading member31at the time of solder-fixing. Therefore, it is possible to maintain a good light leading ability of the light leading member31.

Furthermore, according to this embodiment, the peripheral circuit element62is simply light-press-fitted into the press-fitting concave parts76of the holding member66. Hence, if a certain peripheral circuit element62does not work, only the peripheral circuit element62which does not work is exchanged. Hence, the maintenance when the peripheral circuit element62does not work can be implemented at low cost.

Next, the eighth embodiment of the present invention is discussed with reference toFIG. 20.FIG. 20is a longitudinal sectional view of the lighting device.

In this embodiment, a lighting device80is provided for lighting the document D situated on the contact glass12from a lower side of the contact glass12. The image reading apparatus13(SeeFIG. 4) is formed by the lighting device80and the CCD17(SeeFIG. 4) reading a reflection light (reading light) reflected by the document D after the light output from the lighting device80is irradiated on the document D.

A basic structure of the lighting device80is the same as the lighting device65of the sixth embodiment (SeeFIG. 16andFIG. 17) and the lighting device75of the seventh embodiment (SeeFIG. 18andFIG. 19) of the present invention. A different point of the lighting device80from the lighting devices65and75is that a heat radiation part81is formed at a rear surface side of a surface of the holding member66where the LEDs32and the peripheral circuit element62are light-press-fitted, in the lighting device80. The heat radiation part81is formed in a fin-shaped state so as to be in a direction which the heat radiation part81extends to obliquely and upward at a position where the lighting device80is installed in the image reading apparatus13.

In addition, in the case where the heat radiation part81is formed in the holding member66, it is possible to improve radiation-ability of heat generated by the LED32and the peripheral circuit element62, so that it is possible to prevent the performance of the LEDs32and the peripheral circuit element62from degrading due to the influence of the heat.

Next, the ninth embodiment of the present invention is discussed with reference toFIG. 21.FIG. 21is a longitudinal sectional view of the lighting device.

In this embodiment, a lighting device85is provided for lighting the document D situated on the contact glass12from a lower side of the contact glass12. The image reading apparatus13(See FIG.4) is formed by the lighting device85and the CCD17(SeeFIG. 4) reading a reflection light (reading light) reflected by the document D after the light output from the lighting device85is irradiated on the document D.

The lighting device85includes a light leading member31, the substrate86where the wiring pattern61is formed, plural LEDs32, plural peripheral circuit elements62, and the holding member66with plural press-fitting concave parts76for peripheral circuit elements and the press-fitting concave parts68for the point light sources. The LEDs32are light-press-fitted into the press-fitting concave parts68for the point light sources so as to be held. The peripheral circuit elements62are light-press-fitted into the press-fitting concave parts76for peripheral circuit element.

The holding part34is formed in a body at a side of the incident surface31aof the light leading member31. The holding part34holds the substrate86and the holding member66in a state where the substrate86and the holding member66are stacked.

The holding part34extends along a longitudinal direction of the light leading member31. In the holding part34, a mounting surface34ais formed so as to be in parallel with a longitudinal direction of the light leading member31and orthogonal to the incident surface31a. Plural screw holes87are formed at positions in the holding part34along the longitudinal direction of the holding part34.

The substrate86has a linear rectangular configuration extending in a direction along a longitudinal direction of the light leading member31so as to assemble the lighting device85by using this substrate86. Plural insertion holes88are formed in position along the longitudinal direction. Plural insertion holes89are formed in the holding member86in position along a longitudinal direction of the light leading member31by assembling the lighting device85by using this holding member86. Positioning pins90are inserted into the corresponding insertion holes88and89. A screw part is formed in a head end part of each of the positioning pin90and this screw part is screw-fixed with a corresponding screw hole87of the holding member34. A positioning member91causes a gap between each of the LEDs32arranged in a line state and the light leading member31to be constant by the holding part34having the mounting surface34aand the positioning pins90. The positioning member91also causes an arrangement direction of the LEDs32to be positioned along the longitudinal direction of the light leading member31.

Under this structure, the substrate86and the holding member66are mounted on the mounting surface34aof the holding part34in a state where the substrate86and the holding member66are stacked. Positioning pins90are inserted into the insertion holes88and89. The screw part formed in the head end part of the positioning pin90is screw-fixed with the screw hole87of the holding member34. As a result of this, the holding member66and the substrate86are fixed to the holding part34. The LEDs32and the peripheral circuit elements62are pressed and connected to the wiring pattern61formed on the substrate86. Because of this, it is possible to electrically connect the LEDs32to the peripheral circuit element62.

The mounting surface34aextends in parallel with the longitudinal direction of the light leading member31. Hence, by mounting the holding member66and the substrate66on the mounting surface34a, it is possible to position plural LEDs32which are light-press-fitted in the press-fitting concave parts68for the point light sources of the holding member66and the light leading member31so that the arrangement direction of the LEDs32is consistent with the longitudinal direction of the light leading member31. In addition, by screw-fixing the positioning pins90inserted in the insertion hole89of the holding member66mounted on the mounting surface34aand the insertion hole88of the substrate89into the corresponding screw holes87of the holding part34, it is possible to cause the gap between each of the LEDs32which are light-press-fitted in the press-fitting concave parts68for the point light sources of the holding member66and the incident surface31aof the light leading member31to be made constant. Because of this, the light beams from the LEDs32are uniformly incident on the incident surface31aof the light leading member31. It is possible to uniformly light the document D along a main scanning direction of the document D by the light that is led by the light leading member31after being output from the LED32and then output from the outputting surface31b. Because of this, a light receiving property of a light received by a CCD17is improved and therefore it is possible to improve the quality of an image formed by the printer engine3based on a result of reading by the image reading apparatus13.

Furthermore, according to this embodiment, since the wiring pattern61is formed on an exclusive substrate86, a special process for forming the wiring pattern on the mounting surface34aof the holding part34is not necessary so that productivity can be improved.

Next, the tenth embodiment of the present invention is discussed with reference toFIG. 22.FIG. 22is a longitudinal sectional view of the lighting device.

In this embodiment, a lighting device95is provided for lighting the document D situated on the contact glass12from a lower side of the contact glass12. The image reading apparatus13(SeeFIG. 4) is formed by the lighting device95and the CCD17(SeeFIG. 4) reading a reflection light (reading light) reflected by the document D after the light output from the lighting device95is irradiated on the document D.

A basic structure of the lighting device95is the same as the lighting device85of the ninth embodiment of the present invention. A different point of the lighting device95from the lighting device85is that the positioning pin96and the holding part34are formed in a body in the lighting device95.

A screw part is formed in the head end part of the positioning pin96. The insertion hole88of the substrate86and the insertion hole88of the holding member66have the positioning pin96inserted so that the substrate86and the holding member66are mounted on the mounting surface34aof the holding part34in a state where the substrate86and the holding member66are stacked. A nut97is screw-fixed with the screw part of the head end part of the positioning pin96. By screw-fixing the nut97, the substrate86and the holding member66are fixed to the holding part34.

A positioning member98causes a gap between each of the LEDs32arranged in a line state and the light leading member31to be made constant by the holding part34having the mounting surface34aand the positioning pin96. The positioning member98also makes an arrangement direction of the LEDs32to be positioned along the longitudinal direction of the light leading member31.

Under this structure, the positioning pin96is formed with the holding member34in a body. Hence, when the substrate86and the holding member66are fixed to the holding part34by the positioning pin96, it is possible to improve positioning precision between the holding member66and the holding part34. Because of this, it is possible to uniformly light the document D along a main scanning direction of the document D. Hence, a light receiving property of a light received by a CCD17is improved and therefore it is possible to improve the quality of an image formed by the printer engine3based on a result of reading by the image reading apparatus13.

The present invention is not limited to the above-discussed embodiments, but variations and modifications may be made without departing from the scope of the present invention.

This patent application is based on Japanese Priority Patent Application No. 2004-202998 filed on Jul. 9, 2004, the entire contents of which are hereby incorporated by reference.