JP2000125080A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve quality of a read image by making uniform the quantities of lights irradiating respective lengthwise parts in an image read area without complicatedly machining or processing a light guide body for guiding the light emitted by a light source to the linear image read area. SOLUTION: The image reader is equipped with a light guide body 8 which projects the light emitted by the light source from a certain-length area on a 1st flank 80A so that the linear image read area P is irradiated with the light, a lens array 6 which forms an image by converging the light reflected from the image read area P, photodetectors 20 which receive light converged by the lens array 6 and convert it photoelectrically, and a case 1 forming a storage part 10 which contains the light guide body 8, and the case 1 is provided with a light shield part 13 which cuts off the light of a part where the quantity of projection light is larger than those of other parts as to the light projected from the 1st flank 80A.

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 which is incorporated in a facsimile apparatus or various scanner apparatuses and is used for reading an image on a document.

[0002]

2. Description of the Related Art The applicant of the present application has previously proposed an image reading apparatus of this type described in Japanese Patent Application Laid-Open No. 10-173870. As shown in FIG. 11 of the present application, the conventional light source includes a plurality of light sources 90 such as LEDs that emit light of respective colors of R, G, and B (red, green, and blue). A light guide 91 for guiding the received light to a linear image reading area Pe, a lens array 92 for converging the light reflected from the document D arranged in the image reading area Pe to form an image, and this lens A plurality of light receiving elements 93 that receive the light focused by the array 92 and convert the light into a light source are provided. Each of the above components is incorporated in a case 94.

The light guide 91 is made of a transparent material and has a plurality of side surfaces extending in the same direction as the image reading area Pe. As shown in FIG. 12, a concave portion 95 having a substantially V-shape in a side view is formed at a central portion in the longitudinal direction of the light guide 91. The light source 90 faces the recess 95 with the light guide 91 interposed therebetween. Each of the plurality of side surfaces of the light guide 91 is formed in a mirror surface. However, a plurality of concave grooves 96 are provided at appropriate intervals on the second side surface 91b facing the first side surface 91a serving as the light emitting surface.

As shown in FIG. 13, in the light guide 91, when the light emitted from the light source 90 enters the light guide 91 and reaches the inclined surfaces 95a, 95a of the concave portion 95,
Most of the light is reflected toward both ends in the longitudinal direction of the light guide 91, and thereafter reaches the both ends in the longitudinal direction of the light guide 91 while repeating total reflection by a plurality of side surfaces of the light guide 91. At this time, each groove 9 of the second side surface 91b is formed.
The light that has reached 6 is reflected such that its traveling direction is sharply changed, and a part of the light is incident on the first side surface 91a at an incident angle smaller than the critical angle for total reflection. Then, the light is transmitted through the first side surface 91a as it is, emitted to the outside, and is irradiated on the image reading area Pe.

In the above-described image reading apparatus, although a so-called point light source 90 is used as a light source for illuminating a document, light emitted from the light source 90 is applied to various parts of a linear image reading area Pe. be able to.
Therefore, there is obtained an advantage that the total number of light sources can be reduced, and the cost of parts and running cost can be reduced.

[0006]

However, the conventional image reading apparatus has the following disadvantages.

That is, in the above-described image reading apparatus, it is difficult to make the amount of light emitted from each portion in the longitudinal direction of the first side surface 91a of the light guide 91 uniform. Tend to be much larger than the amount of light emitted from other parts. In this state, the illuminance at the central portion in the longitudinal direction of the image reading area Pe becomes higher than the illuminance at other portions, and it becomes impossible to read the original image faithfully.
For this reason, conventionally, an opaque member is adhered to the central portion in the longitudinal direction of the first side surface 91a, or a light-shielding paint is applied to provide a light-shielding portion 97 in that portion,
Thus, the amount of light emitted from the central portion in the longitudinal direction of the first side surface 91a toward the image reading area Pe is reduced.
However, with such means, the light guide 91 is provided with the light shielding portion 9.
7 is complicated, and productivity is deteriorated.

The present invention was conceived under such circumstances, and a complicated processing and processing is required for a light guide for guiding light emitted from a light source to a linear image reading area. It is an object of the present invention to improve the quality of a read image by making it possible to equalize the amount of light applied to each portion in the longitudinal direction of an image reading area without causing the necessity of performing the image reading.

[0009]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

An image reading apparatus provided by the present invention comprises: a light guide made of a transparent member for guiding light emitted from a light source to irradiate a linear image reading area; A lens array for converging the light that has come and forming an image.
A plurality of light-receiving elements for receiving the light converged by the lens array and performing photoelectric conversion, and a case forming an accommodating portion for accommodating the light guide; By reflecting light incident on the inside of the light guide from the light source by a plurality of side surfaces of the light guide,
An image reading device, wherein the light is emitted from a fixed length region of a first side surface of the plurality of side surfaces while traveling in a direction in which the image reading region extends. The light guide is characterized in that a light-shielding portion is provided to block a portion of the light emitted from the first side surface of the light guide, which emits a larger amount of light than others.

According to the present invention, a groove for accommodating the lens array is formed inside the case, and a part of a partition for separating the groove from the accommodation portion serves as the light shielding portion. It can be configured. Further, in the present invention, the light source is an LED light source provided to face a longitudinal end portion of the light guide, and the light guide is emitted from the LED light source and emits light of the light guide. It is also possible to adopt a configuration in which the light incident into the longitudinal end portion is emitted from the fixed length region of the first side surface while traveling in the longitudinal direction of the light guide.

In the present invention, when light is emitted from a fixed length region of the first side surface of the light guide, light in a portion where the amount of emitted light increases is controlled by a light shielding portion provided in the case. The light can be blocked, and the image reading area can be prevented from being irradiated with an extremely large amount of light. For this reason, the amount of light applied to the image reading area via the portion where the amount of emitted light increases on the first side surface of the light guide and the amount of light applied to the image reading area via the other portions are different. By making them equal, it is possible to make uniform the amount of irradiation light to each part in the longitudinal direction of the image reading area, and to obtain a high quality read image. On the other hand, in the present invention, since a means for providing a light-shielding portion in the case is employed as means for making the amount of irradiation light uniform to the image reading area, a light-shielding portion is provided on the light guide unlike the conventional case. It is possible to eliminate the necessity of performing special processing and processing for the above. In addition, the light-shielding portion of the case can be formed by, for example, resin molding when the case is molded with resin, and can be easily formed without requiring any special processing operation. Therefore, according to the present invention, the productivity of the image reading apparatus can be increased, and the manufacturing cost can be reduced.

In a preferred embodiment of the present invention, the light-shielding portion is provided so as to block light emitted from a portion near the light source in the first side surface of the light guide.

When light is emitted from the first side surface of the light guide, there is a tendency that the amount of light emitted from a portion near the light source in each of the longitudinal portions of the first side surface is maximized.
According to the above configuration, it is possible to block the light of the portion where the amount of emitted light is maximum by the light shielding portion, and to achieve uniform irradiation light amount to each portion in the longitudinal direction of the image reading area.

In another preferred embodiment of the present invention,
The light-shielding portion is provided so as to face a portion where the amount of emitted light is the largest and a portion other than the portion in the longitudinal direction of the first side surface of the light guide, and is emitted from a portion where the amount of emitted light is large. The more light, the greater the amount of light blocked by the light-blocking portion.

According to such a configuration, when the amount of light emitted from each portion in the longitudinal direction of the first side surface of the light guide varies in several stages, the light in the portion where the amount of emitted light is maximized. Maximizes the amount of light blocking by the light blocking part,
It is possible to slightly reduce the amount of light shielding by the light shielding unit for light in a portion where the amount of emitted light is smaller, and to further reduce the amount of light shielding by the light shielding unit for light in a portion where the amount of emitted light is smaller. Therefore, it is possible to make the distribution of the irradiation light amount on the image reading area finer and more uniform.

In another preferred embodiment of the present invention,
The light guide includes a second side facing the first side in the thickness direction of the light guide, and a third side and a fourth side facing each other in the width direction of the light guide. And
The second side surface has a surface capable of scattering and reflecting light traveling in the light guide, and the third side surface and the fourth side surface reflect light traveling in the direction of the second side surface. It is a curved surface that reflects so as to make the light beam bundle of light beams substantially parallel to each other and proceed toward the first side surface.

According to such a configuration, when the light emitted from the light source and entering the light guide travels inside the light guide, the light reaching the second side surface of the light guide is transmitted to the light guide. By scattering and reflecting, a part of the light can travel toward the third side surface or the fourth side surface. Then, the light is reflected by the third side surface and the fourth side surface so that the light is made to travel toward the first side surface as a bundle of light beams substantially parallel to each other. It can be emitted outside. Therefore,
It is possible to suppress the light emitted from the first side surface from propagating so as to spread in various directions, and to irradiate the light intensively on the image reading area to increase the efficiency of light irradiation on the image reading area. it can.

Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a sectional view of an essential part showing an example of an image reading apparatus according to the present invention. FIG. 2 is a sectional view taken along the line II-II in FIG.
It is sectional drawing. FIG. 3 is a sectional view taken along the line III-III of FIG. FIG. 4 is a sectional view taken along line IV-IV of FIG. FIG.
FIG. 5 is an exploded perspective view of the image reading device shown in FIG.

The image reading apparatus A of the present embodiment is configured as a so-called close contact type image sensor. FIG.
As is apparent from FIG.
Case 1, substrate 4, a plurality of sensor IC chips 2 mounted on substrate 4, one LED light source 3, document guide plate 5, lens array 6, reflector 7, light guide 8, and one or more attachments 59. As described later, the sensor IC chip 2
Has a plurality of light receiving elements 20.

The case 1 is made of a synthetic resin, and is formed in an elongated box shape having a housing portion 10 having an upper surface opening. The above-described components of the image reading apparatus A are assembled in the case 1. The original guide plate 5
Is for placing a document in opposition, and is made of, for example, transparent glass or synthetic resin. 2 and 3
The document guide plate 5 is mounted on the upper surface of the case 1 so as to close the upper part of the storage section 10 of the case 1. In the upper surface of the document guide plate 5, the portion immediately above the lens array 6 is an image reading area P, and the image reading area P extends in a line in the longitudinal direction of the case 1 and the document guide plate 5. For example, a platen roller 58 is disposed on the upper surface of the document guide plate 5, and the document D is transported in the sub-scanning direction by the platen roller 58.

FIG. 6 is a partially cutaway perspective view showing the light guide 8. FIG. 7 is a sectional view taken along line VII-VII of FIG. FIG. 8 is an explanatory view showing the operation of the light guide 8.

The light guide 8 serves to efficiently guide the light emitted from the LED light source 3 to the entire length of the image reading area P. The light guide 8 is, for example, a PMM
The light guide 8 is made of an acrylic transparent resin such as A or other highly transparent members, and the surface of each part of the light guide 8 is a mirror surface. If the surface of the transparent member is made to be a mirror surface, when light is guided inside the transparent member, light rays incident on the surface of the transparent member at an angle larger than the total reflection critical angle specified by the material of the transparent member are reflected. It can be totally reflected. On the other hand, a light ray incident at an angle smaller than the critical angle for total reflection can be transmitted to the outside of the transparent member as it is. It should be noted that the mirror surface does not necessarily need to be a surface whose surface is actively polished. For example, when the light guide 8 is resin-molded using a mold, a relatively smooth surface obtained by the resin molding may be used.

The light guide 8 can be divided into an auxiliary region Sb at one end in the longitudinal direction of the light guide 8 and a main region Sa other than the auxiliary region Sb. The auxiliary area Sb is a part that plays a role in advancing light emitted from the LED light source 3 into the main area Sa. The auxiliary region Sb is provided with a downward projection 81, a downward bottom surface 82, two tapered surfaces 86a and 86b connected to an end surface 85, and the like. The bottom surface 82 serves as a light incident surface that receives light from the LED light source 3, and light emitted from the LED light source 3 passes through the bottom surface 82 and enters the auxiliary area Sb. As shown in FIG. 7, the tapered surfaces 86a and 86b are flat or curved surfaces capable of totally reflecting the light that has entered the auxiliary region Sb via the bottom surface 82 toward the main region Sa. The protrusion 81 serves to secure a space for disposing the LED light source 3 below the bottom surface 82.

The main area Sa travels in the longitudinal direction of the main area Sa while traveling from the auxiliary area Sb while transmitting the light to the first side surface 80A of the main area Sa.
It is a part that plays a role of emitting light from the entire length region of. That is, the main region Sa has a substantially uniform cross-sectional shape at various points in the longitudinal direction, and the first side surface 80A and the second side surface 80B facing the light guide 8 in the vertical thickness direction, and the light guide 8 And a third side surface 80C and a fourth side surface 80D that face each other in the left-right width direction. These sides 80A-80D
Extend in the longitudinal direction of the light guide 8.

As is clearly shown in FIG. 8, the first side surface 80A is formed as an aspherical convex surface whose central portion in the width direction bulges beyond its side edge. The third above
Each of the side surface 80C and the fourth side surface 80D is formed as a paraboloid (secondary curved surface) having the width direction center line C in the main region Sa of the light guide 8 as a common main axis.
6, the center line C is inclined with respect to the center line C1 in the width direction in the auxiliary area Sb. This will be described later with respect to the auxiliary area Sb.
This is because the bottom surface 82 needs to face the LED light source 3, whereas the main region Sa needs to have the first side surface 80 A facing the image reading region P. As is clearly shown in FIG. 8, the second side surface 80B
Is formed as a plane passing through the common focal point O1 of the respective paraboloids of the third side face 80C and the fourth side face 80D or the vicinity thereof. As shown in FIG. 7, a plurality of recesses 84 are provided at appropriate intervals in the second side surface 80B. The region between the plurality of recesses 84, 84 is a mirror-like plane. The plurality of recesses 8
Reference numeral 4 denotes a portion which plays a role of rapidly changing the traveling direction by scattering and reflecting light in the light guide 8, and has, for example, an arc-shaped cross section. However, as another means for changing the traveling direction abruptly by scattering and reflecting the light in the light guide 8, for example, means for providing a plurality of convex portions on the second side surface 80B at appropriate intervals, light A means for applying a paint or the like capable of scattered reflection to the second side face 80B, or a means for making the whole or a part of the second side face 80B a rough surface with minute unevenness can be adopted.

In the light guide 8, when the light emitted from the LED light source 3 enters the auxiliary area Sb and then proceeds toward the main area Sa, the light is transmitted to the first side face 80.
A, each part of the third side face 80C and the fourth side face 80D,
The light travels toward the end face 80E at one end in the longitudinal direction of the light guide 8 while repeating total reflection in the plane portion of the second side face 80B. The light that has entered the concave portion 84 of the second side surface 80B is scattered and reflected in various directions, and its course is rapidly changed, so that most of the light is, as shown in FIG.
The light travels toward the side surface 80C and the fourth side surface 80D, and is totally reflected by these side surfaces. However, as described above, the third side surface 80C and the fourth side surface 80C
Since D is a paraboloid and the second side face 80B is located at or near the focal point O1 of the paraboloid, a large number of reflected by the third side face 80C and the fourth side face 80D The light beams travel toward the first side surface 80A as a light beam substantially parallel to the principal axis of the paraboloid, and exit from the first side surface 80A to the outside. Also, since the first side surface 80A is convex, the first side surface 8A
Light emitted from 0A travels so as to be focused on a predetermined focal point O2. Such light emission is performed in the entire length region of the first side surface 80A.

In FIG. 5, the reflector 7 is for supporting the light guide 8. The reflector 7 has an overall length substantially the same as the overall length of the light guide 8, and a groove 7 opened on one side of the reflector 7.
0 extend in the longitudinal direction of the reflector 7 and are formed in series. As best seen in FIGS. 2 and 3, the light guide 8 is supported by the reflector 7 in a fixed posture by fitting into the groove 70. The reflector 7 is fitted into the housing 10 of the case 1,
As a result, the first side surface 80A of the light guide 8 extends in the same direction as the image reading area P, and
Facing. The reflector 7 is engaged with a locking rib 19 provided on the case 1, for example,
It is positioned so as not to be inadvertently moved above the accommodation section 10.

The wall 70 of the groove 70 of the reflector 7
b to 70d are in opposing contact with each of the second side surface 80B, the third side surface 80C, and the fourth side surface 80D of the light guide 8, and the light traveling inside the light guide 8 is Plays a role in preventing leakage to the outside. 1 and 5, the reflector 7 has one end 7a in the longitudinal direction formed in a shape capable of covering the outer surface of the auxiliary area Sb of the light guide 8, and the reflector 7 has the longitudinal direction. On the other end 7b, a wall surface 70e capable of covering the end surface 80E of the light guide 8 is formed.
Therefore, as shown in FIG. 1, the light emitted from the LED light source 3 and traveling into the auxiliary area Sb of the light guide 8 leaks out of the auxiliary area Sb. The light that has reached the end face 80 </ b> E can be prevented from leaking to the outside as it is by the reflector 7. The reflector 7 is made of, for example, a white synthetic resin, and a surface facing the light guide 8 has a white light reflectance. In the present embodiment, the reflector 7 is a single member. However, in the present invention, instead of this, for example, the main region Sa and the auxiliary region Sb of the light guide 8 are individually covered by two reflectors separately formed. You can do it.

In FIGS. 2 and 3, the lens array 6 irradiates the image reading area P from the first side face 80A of the light guide 8 and reflects the light reflected by the original D onto the surface of the plurality of light receiving elements 20. This is to focus and form an image. As the lens array 6, for example, a lens array having a structure in which a plurality of SELFOC lenses that form an image of an original at an erect equal magnification and arranged in a row and held by a holder made of synthetic resin or the like is applied. This lens array 6
By being fitted into the groove 12 formed in the case 1, it is disposed immediately below the document guide plate 5.

The groove 12 of the case 1 and the housing 10
Between them, a partition wall 13 'separating them is formed. As shown in FIG. 2, a part of the partition 13 ′
The light shielding portion 13 facing a part of the first side surface 80A of the light guide 8
It has been. More specifically, the partition 13 '
Although it is formed so as to extend in a series in the same direction as the image reading area P, its height is not uniform everywhere.
As shown in (1), the portion near the LED light source 3 is formed at a height facing a relatively large area of the first side surface 80A of the light guide 8. The portion of the partition wall 13 ′ facing the first side surface 80 </ b> A corresponds to the light blocking portion 13.
On the other hand, as shown in FIG. 3, at a portion relatively far from the LED light source 3, the partition 13 'is formed at a lower height than the portion shown in FIG. The light shielding portion facing the first side surface 80A is not provided, or even if the light shielding portion is provided, the first side surface 80A is not provided.
The area facing A is very small.

The plurality of sensor IC chips 2 are formed by integrally forming a plurality of light receiving elements 20 on one side of an elongated rectangular semiconductor chip, and the light focused by the lens array 6 is received by the light receiving elements 20. The photoelectric conversion is performed by receiving the light, and an image signal having an output level corresponding to the amount of received light is output. These multiple sensor ICs
The chips 2 are mounted in a row in the longitudinal direction of the substrate 4.

The LED light source 3 includes, for example, R, G, B
The three types of LED chips that emit light of each color are collectively packaged in a resin, and are capable of reading a color original. Needless to say, when reading a monochrome document, an LED light source that emits white light or another monochromatic light may be used. The LED light source 3 is mounted on the same surface of the substrate 4 on which the sensor IC chip 2 is mounted.

The substrate 4 is mounted on the bottom of the case 1 such that the plurality of light receiving elements 20 are located directly below the lens array 6 and the LED light source 3 faces the bottom 82 of the light guide 8. I have. The assembly of this board 4
Locking projections 14 formed on both side surfaces of the case 1;
14, the upper ends of the attachment 59 are hooked, and the center of the bottom of the attachment 59 is attached to the substrate 4.
This is done by making contact with the back surface of the. On the surface of the substrate 4, the plurality of sensor IC chips 2 and LE
A conductive wiring pattern (not shown) for inputting / outputting a signal to / from the D light source 3 and supplying power is formed, and is configured so that connection to an external device can be performed via the connector 40.

Next, the operation of the image reading apparatus A will be described.

In the image reading device A, when the LED light source 3 is driven to light, as described above, the light emitted from the LED light source 3 enters the light guide 8 from the bottom surface 82 of the light guide 8. Then, the light travels in the main area Sa of the light guide 8 in the longitudinal direction. Then, the light is emitted from the entire length area of the first side face 80A, and is irradiated on the surface of the document D located in the linear image reading area P. In this case, since light is made to enter the light guide 8 only from one end in the longitudinal direction, a portion near the LED light source 3 in each of the longitudinal directions of the first side surface 80A, that is, FIG. Sign of 1 N
The amount of light emitted from the portion indicated by becomes larger than the amount of light emitted from the other portions. However, in the image reading device A, as shown in FIG. 2, the light shielding portion 13 is provided so as to face the portion where the amount of emitted light is large. Can be prevented from being irradiated. For this reason, it is possible to prevent the amount of irradiation light to the image reading area P from locally increasing, and to make the amount of irradiation light to various parts in the longitudinal direction of the image reading area P uniform. As a result, it is possible to prevent the quality of the read image from deteriorating due to the variation in the irradiation light amount.

In the image reading device A, the light traveling in the light guide 8 can be prevented by the reflector 7 from leaking outside through the side different from the first side 80A. Further, since most of the light traveling from the first side surface 80A toward the image reading area P can be focused on a predetermined focal point O2, the image reading area P
Can be intensively irradiated with light. Therefore, the light irradiation efficiency to the image reading area P can be improved.

The specific configuration of each part of the image reading apparatus according to the present invention is not limited to the above-described embodiment.

In the present invention, the first side surface 80A of the light guide 8 is provided.
Of these, not only the light emitted from the portion where the amount of emitted light is maximum is not blocked by the light blocking portion, but a part of the light emitted from other portions may be blocked by the light blocking portion. . That is, the first side surface 8 of the light guide 8
Unlike the case where only the portion close to the LED light source 3 has an extremely large amount of emitted light from various locations in the longitudinal direction of 0A compared to other portions, for example, the closer to the LED light source 3, the larger the amount of emitted light becomes. In such a case, the light-shielding portion is provided so as to face a relatively long dimension area in the longitudinal direction of the first side surface 80A, and the amount of light blocked by the light-shielding portion increases in a portion closer to the LED light source 3. It does not matter.

In the present invention, the specific structure of the light guide is not limited to that of the above embodiment. For example, the light guide shown in the conventional example may be used. The structure shown in FIG. 10 may be used. In the structure shown in FIG. 9, the bottom surfaces 82 at both ends in the longitudinal direction of the light guide 8A,
The LED light source 3 is opposed to each of the light guides 82 so that light can enter the light guide 8A from those two places. According to such a configuration, the amount of light incident on the light guide 8A can be increased, which is more preferable in increasing the illuminance of the image reading area. In the structure shown in FIG. 10, the LED 80B is provided on the end face 80H at the longitudinal end of the light guide 8B.
The light source 3 is opposed. With such a configuration, L
Most of the light emitted from the ED light source 3 and transmitted through the end face 80H can proceed in the longitudinal direction of the light guide 8B as it is, and the light can be appropriately emitted from the first side face 80A of the light guide 8B. be able to. Thus, in the present invention, it does not matter from which part of the light guide the light emitted from the light source is incident, and the specific shape of the light guide is not limited.

In addition, in the present invention, a light source of a type different from the LED light source can be used as the light source. Further, the image reading device according to the present invention may be configured as a contact image sensor of a type used as a handy scanner, for example, instead of being configured as a contact image sensor of a type in which a platen roller is disposed to face. Good. Further, a case in which a light source, a light guide, and the like are assembled may be configured as a so-called flatbed type image sensor provided movably in the sub-scanning direction below the document placing plate.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an example of an image reading apparatus according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG.

FIG. 4 is a sectional view taken along line IV-IV of FIG.

FIG. 5 is an exploded perspective view of the image reading device shown in FIGS. 1 to 4;

FIG. 6 is a partially cutaway perspective view showing an example of a light guide.

FIG. 7 is a sectional view taken along line VII-VII of FIG. 6;

FIG. 8 is an explanatory view showing an operation of the light guide.

FIG. 9 is an explanatory view showing another example of the light guide.

FIG. 10 is a sectional view of a main part showing another example of the light guide.

FIG. 11 is a cross-sectional view illustrating an example of a conventional image reading apparatus.

FIG. 12 is an explanatory diagram showing a combination structure of a light guide and a light source of the image reading device shown in FIG.

FIG. 13 is an explanatory view showing the operation of the combined structure of the light guide and the light source of the image reading apparatus shown in FIG.

[Explanation of symbols]

 Reference Signs List A Image reading device P Image reading area D Document 1 Case 2 Sensor IC chip 3 LED light source 4 Board 5 Document guide plate 6 Lens array 7 Reflector 8, 8A, 8B Light guide 10 Housing 12 Groove 13 Light shielding 13 'Partition Reference Signs List 20 light receiving element 80A first side 80B second side 80C third side 80D fourth side

Continued on the front page F term (reference) 2H109 AA02 AA12 AA26 AA51 AA83 AA94 5B047 AA01 BA01 BB02 BC02 BC05 BC12 BC15 BC16 CA14 CA19 CB04 CB09 CB22 5C051 AA01 BA02 DA03 DB01 DB22 DB29 DC04 DC05 DC07 DE15 CA03 DA15 CA03 DA20 DA21 EA05 QA14 RA06

Claims (6)

[Claims] 1. A light guide made of a transparent member for guiding light emitted from a light source to irradiate a linear image reading area, and condensing light reflected from the image reading area to form an image. A lens array for performing an image, a plurality of light receiving elements for receiving light converged by the lens array and performing photoelectric conversion, and a case forming an accommodation portion for accommodating the light guide, And the light guide reflects light incident on the inside of the light guide from the light source by a plurality of side surfaces of the light guide, so that the image reading area extends. An image reading device configured to emit light from a fixed length region of a first side surface of the plurality of side surfaces while traveling in a direction, wherein the case includes a first side surface of the light guide. Emitted from That of the light, wherein the light shielding portion is provided to block light portion emitted light quantity is larger than the other, the image reading apparatus. 2. The image reading device according to claim 1, wherein the light shielding portion is provided so as to block light emitted from a portion near the light source in the first side surface of the light guide. 3. The light-shielding portion is provided so as to face a portion where the amount of emitted light is maximized and a portion other than the portion in the longitudinal direction of the first side surface of the light guide, and the amount of emitted light is reduced. The image reading device according to claim 1, wherein an amount of light blocked by the light blocking unit increases as light emitted from a larger portion. 4. A case in which a groove for accommodating the lens array is formed inside the case, and a part of a partition part separating the groove from the accommodation part is the light-shielding part. Item 4. The image reading device according to any one of Items 1 to 3. 5. The light source is an LED light source provided so as to face a longitudinal end of the light guide, and the light guide is emitted from the LED light source and has a longitudinal length. 5. The light guide according to claim 1, wherein the light incident into the direction end is emitted from a fixed length region of the first side surface while traveling in the longitudinal direction of the light guide. 6. Image reading device. 6. The light guide includes a second side facing the first side in the thickness direction of the light guide, a third side and a fourth side facing each other in the width direction of the light guide. And the second side has a surface capable of scattering and reflecting the light traveling in the light guide, and the third and fourth sides have the second side. The image reading device according to claim 1, wherein the image reading device has a curved surface that reflects the light traveling from the direction described above as a bundle of substantially parallel light beams so as to travel toward the first side surface. apparatus.