JP2005252646A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a uniform light guided to a reading target region with a little loss in an image reader. <P>SOLUTION: A light emitted from an LED is reflected possibly in the total reflecting condition in an optical guide to guide it to an optical guide emitting face, the light intensity is improved in the short axis direction (sub scanning direction) of the original surface, and the optical guide incident surface shape is optimized to control the angle of a light beam in the long axis direction (main scanning direction) of the original surface, thus obtaining the shape of the optical guide for irradiating the original surface at a uniform intensity distribution. A reflector is provided at the opposite side to the emitting surface to improve the irradiation efficiency of the light on the image reading target area. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus, and more particularly to an illumination optical system thereof.

  In an image sensor such as a facsimile, a copying machine, or a scanner that reads reflected light from a document to be read by a sensor, an LED is currently widely used as an illumination optical system.

  The invention of Patent Document 1 relates to a basic configuration of a color sequential readout type contact image sensor, and presents a high-sensitivity image sensor with uniform output levels of red, green, and blue. The image reading apparatus disclosed in Patent Document 2 can improve the quality of a read image by increasing the illuminance of the image reading area by using simple means to efficiently guide light emitted from the light source to the image reading area. . However, since the surface of the hollow light guide is white, a large amount of light diffuses and light cannot be efficiently guided to the document surface.

  The invention of Patent Document 3 makes it possible to easily perform assembling work of predetermined parts such as a light source constituting the image reading apparatus and electric wiring work without causing trouble in the image reading function and the like. The manufacturing cost is reduced. However, in the image reading apparatus, since the LED light is introduced into the light guide only from the side surface or the center bottom surface, there is a limit when increasing the number of LEDs to increase the illumination intensity (the LED introduction opening of the light guide is small).

  The invention of Patent Document 4 provides a color image sensor and an image reading apparatus capable of efficiently and uniformly guiding light from a light source to a reading surface. However, since the light is guided by the curved prism, the spread angle of the emitted light is increased and the irradiation area on the document surface is increased, so that the efficiency of using illumination light is reduced in linear reading.

  The invention of Patent Document 5 enables light emitted from a light source device of an image reading apparatus to be efficiently and appropriately guided to a desired line-shaped reading target area. However, the shape of the combination lens is complicated, and high accuracy is required for manufacturing.

Further, in the illumination optical system in the conventional image reading apparatus including the inventions of Patent Documents 1 to 5, the irradiation angle is biased by the direct irradiation light beam irradiated from the light guide means to the document surface. As a result, a shadow is generated when the document surface is wrinkled. That is, the reading optical system reads wrinkles on the document surface.
JP 2001-136341 A JP-A-11-215301 JP 11-55456 A JP 2000-349957 A JP 2001-77975 A

  In the image reading apparatus, the light emitted from the LED is reflected as much as possible in the light guide under the total reflection condition and guided to the light guide exit surface, and the light intensity in the minor axis direction (sub-scanning direction) on the document surface In addition to optimizing the shape of the entrance surface of the light guide, the angle of the light beam in the long axis direction (main scanning direction) is controlled, and thus the illumination surface is irradiated with illumination light having a uniform intensity distribution. The purpose is to obtain the shape of the body. A further object of the present invention is to prevent wrinkles on the document surface from being read by setting the reflecting portion.

The present invention has been made to achieve the above object. An image reading apparatus according to the present invention includes:
One or more light sources for illuminating the document surface;
A light guide means having a light entrance surface and a light exit surface for entering and exiting light so that the light emitted from the light source travels into the transparent member and is guided to a linear reading target region;
An optical system for collecting the light reflected from the document surface;
An image reading apparatus provided with an image forming unit of the optical system and provided with a sensor that reads an image of the document. In the image reading apparatus,
The light guide means includes a light source storage portion having a substantially rectangular light emission surface that is long in the major axis direction of the linear reading target region on the upper surface, and a light source storage portion on which the light source is installed on the lower surface, and the wall surface of the light source storage portion Is the light incident surface,
The side surface of the light guide means has a first surface and a second surface across the thickness of the light guide means in the short axis direction parallel to the long axis direction of the light guide means, and the light guide means A seventh surface and an eighth surface across the major axis thickness of the light guide means in parallel with the minor axis direction of
About the short axis direction of the linear reading area
The light emitted from the light source, incident on the light incident surface of the light guide means through the light source housing, is reflected by the first surface and the second surface, and is guided to the light emitting surface. While leading to a linear reading target area,
A linear reading target region is provided by providing a reflecting surface for reflecting a part of the light emitted from the light emitting surface of the light guide, with an optical system for collecting the light reflected from the document surface being separated. It is characterized by having a structure that leads to

  By utilizing the present invention, in the image reading apparatus, the light emitted from the light source can be efficiently guided to the reading target area. Further, since the illumination light is uniformly distributed in the document, the image of the document can be read accurately. In particular, the setting of the reflecting portion prevents wrinkles on the document surface from being read.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view in the minor axis direction (sub-scanning direction) of the image reading apparatus according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of a part of the image reading apparatus according to Embodiment 1 of the present invention. In the image reading apparatus, the document 3 is sandwiched between the glass 2 and the platen 4 on the housing 1 and is fed by the platen 4. The housing 1 includes an illumination optical system and a reading optical system under the glass 2. The illumination optical system includes a light source substrate 9 and a light guide means 10. The light guide unit 10 guides light emitted from the light source 5 such as an LED installed on the bottom of the light source substrate 9 and irradiates the original 3 to be read through the glass 2. The reading position of the document 3 is linear in the main scanning direction. The reading optical system includes a rod lens array 6 and a sensor substrate 8 on which a line sensor IC 7 is mounted. The read light from the document 3 is transferred to the line sensor IC 7 as a normal image by the rod lens array 6, and is converted into an electric signal by the line sensor IC 7. Since the document 3 is moved by the platen 4, the information on the entire document surface can be finally converted into an electric signal.

  In the image reading apparatus described above, the illumination optical system is appropriately adjusted so that the light from the light source 5 properly reaches the document 3, and the reading optical system so that the light from the document 3 properly reaches the line sensor IC 7. Adjust as appropriate.

  The light guide means 10 is sandwiched between the first surface 11 and the second surface 12 in the short axis direction and between the seventh surface 47 and the eighth surface 48 in the long axis direction. (Refer to FIGS. 6 and 7 for the seventh surface 47 and the eighth surface 48). A light source storage unit 20 is formed at the bottom of the light guide means 10, and the light source 5 is installed inside the light source storage unit 20. The wall surface of the light source storage portion serves as a light incident surface 17 (see FIG. 6) to the light guide means 10.

  The luminous flux directly irradiated onto the document surface from the light guide means 10 (direct irradiated luminous flux) has a uniform irradiation angle distribution. Therefore, when illumination is performed using only the luminous flux, a shadowed portion occurs when the original surface is wrinkled, and the original optical surface reads the wrinkle on the original surface.

  Therefore, in the image reading apparatus according to Embodiment 1 of the present invention, the reflection unit 35 is provided on the opposite side across the reading optical system. The reflecting portion 35 reflects a part of the light emitted from the light guide (reflected illumination light beam) and guides it to the document surface. As a result, a portion that is shaded by only the light beam directly applied to the document surface from the light guide means 10 is illuminated by the reflected light beam. Therefore, it is difficult to cause wrinkles on the document surface to be read by the reading optical system.

  For example, FIG. 3 shows a simulation example of the angular distribution of light irradiated on the document surface. The light beam directly irradiated from the light guide has an incident angle of approximately +30 degrees to +60 degrees with respect to the document surface. On the other hand, since the light beam applied to the document surface from the reflector 35 has an incident angle of -30 degrees to -60 degrees, the incident angle on the document surface is almost symmetrical, and the generation of shadows due to wrinkles on the document surface is reduced. Is done.

Embodiment 2. FIG.
FIG. 4 is a cross-sectional view in the minor axis direction (sub-scanning direction) of the image reading apparatus according to Embodiment 2 of the present invention. The second embodiment shown in FIG. 4 is substantially the same as the first embodiment shown in FIG. Accordingly, the same parts are denoted by the same reference numerals and description thereof is omitted.

  In the image reading apparatus according to the second embodiment, the ninth surface 21 and the tenth surface 22 are provided between the first surface 11 and the second surface 12 of the light guide unit 10 and the emission surface. Each of the ninth surface 21 and the tenth surface 22 forms a predetermined angle with each of the first surface 11 and the second surface 12.

  Further, the light source substrate 9 is not orthogonal to the first surface 11 and the second surface 12 as in the first embodiment, but “is not 90 °” with the first surface 11 and the second surface 12. An angle can be formed.

  Thus, it can be said that the illuminance difference between the direct irradiation light beam and the reflected irradiation light beam can be smaller than that in the first embodiment. Therefore, the generation of shadows due to wrinkles on the document surface is further reduced.

Embodiment 3 FIG.
FIG. 5 is a cross-sectional view in the minor axis direction (sub-scanning direction) of an image reading apparatus according to Embodiment 3 of the present invention. The third embodiment in FIG. 5 is substantially the same as the first embodiment in FIG. 1 or the second embodiment in FIG. Accordingly, the same parts are denoted by the same reference numerals and description thereof is omitted.

  In the image reading apparatus according to Embodiment 3, the length and angle of the first surface 11 and the second surface 12, the ninth surface 21 and the tenth surface 22 of the light guide means 10 are adjusted. The light source 5 can be arranged on the same substrate as the line sensor IC 7. That is, the light source substrate and the sensor substrate 8 are integrated.

  As described above, the number of parts constituting the image reading apparatus is reduced, and the assembly of the apparatus is simplified.

Embodiment 4 FIG.
FIG. 6 is a cross-sectional view in the major axis direction (main scanning direction) of the light guide means 10 used in the image reading apparatus according to Embodiment 4 of the present invention. On the other hand, FIG. 7 is a longitudinal sectional view of the light guiding means 10 that can be assumed as a comparative example.

  If the shape of the light guide means 10 is a simple rectangular parallelepiped as shown in FIG. 7, the incident angle of a part of the light beam reaching the light exit surface 18 exceeds the total reflection condition. Some of these light beams cannot extract light from the light exit surface 18 of the light guide means 10. Then, as shown in FIG. 8, the illuminance distribution on the document surface 3 in the long axis direction is higher at the center but lower toward the periphery.

  In order to cope with this, in the light guide means 10 in FIG. 6, oblique cut surfaces are formed as the third surface 13 and the fourth surface 14 at positions near the lower end of the rectangular parallelepiped. . The third surface 13 and the fourth surface 14 extend outward from the vicinity of the light source storage unit 20 on the bottom surface of the light guide means 10 (seventh surface 47, eighth surface 48) and extend. The third surface 13 and the fourth surface 14 reflect the light beam having an angle that is a total reflection condition when the direct light beam reaches the light emitting surface 18, and enter the light emitting surface 18 without being totally reflected. The light beam is effectively guided to the document surface 3. Here, by adjusting the inclination angle and interval of the third surface 13 and the fourth surface 14 of the light guide means 10 according to the height of the light guide means 10, uniform illumination as shown in FIG. An intensity distribution can be obtained.

  If the third surface 13 and the fourth surface 14 of the light guide means 10 are reflected under the total reflection condition, it is not necessary to apply a reflective coat to the third surface 13 and the fourth surface 14.

  Further, according to repeated trials, the width in the major axis direction of the block of the light guide means 10 shown in FIG. 6 is within 4 times, preferably within 3 times the distance from the line sensor IC 7 to the document surface. In this case, it is easy to obtain a uniform illuminance distribution in the main scanning direction in the line sensor (IC). For example, if the distance from the line sensor IC 7 to the document surface is 10 mm, and the width in the major axis direction of the block of the light guide means 10 is changed from 30 mm to 40 mm, the desired illuminance is uniform with the minimum number of blocks (the minimum number of LEDs). Sex is obtained.

  Here, the light guide means may be any material that is transparent to the illumination light. For production convenience, transparent resin materials such as polycarbonate and acrylic are desirable. Moreover, as the light source 5, white LED or three primary color LED can be considered. This embodiment can also be applied to a system in which a color filter is provided on the line sensor surface. Further, in the case of three primary color LEDs, it can also be applied to a field sequential method in which R, G, and B are sequentially turned on.

Embodiment 5 FIG.
FIG. 10 is a cross-sectional view in the minor axis direction (sub-scanning direction) of the light guide means 10 used in the image reading apparatus according to Embodiment 5 of the present invention. On the other hand, FIG. 11 is a short-axis direction cross-sectional view of the light guide means 10 that can be assumed as a comparative example.

  As shown in FIG. 11, when the light guide means 10 is formed so that the short-axis direction in the vicinity of the light source substrate 9 has a simple rectangular cross section (part of it), the light enters the light guide means 10 from the light source 5 to guide the light. A part of the light beam reaching the first surface 11 and the second surface 12 of the means 10 becomes an angle that satisfies the total reflection condition (about 45 degrees) and jumps out of the light guide means 10. In particular, in a surface-mount type LED, the luminous angle is large, and the luminous flux having an angle of 45 degrees or more with the front direction as 0 degree reaches 20% to 50% of the total luminous flux.

  Therefore, as shown in FIG. 10, a fifth surface 15 and a sixth surface that are inclined are provided at the lower end portion. The fifth surface 15 and the sixth surface 16 reflect as much of the light flux as possible and guide it to the light emitting surface 18 of the light guide means 10. With such a configuration, loss of illuminance to the original surface is reduced, and the illuminance on the original surface can be further improved.

Embodiment 6 FIG.
FIG. 12 is a cross-sectional view in the minor axis direction of the light guide means 10 of the image reading apparatus according to Embodiment 6 of the present invention. The sixth embodiment shown in FIG. 12 is substantially the same as the third embodiment shown in FIG. Accordingly, the same parts are denoted by the same reference numerals and description thereof is omitted.

In FIG. 12, the reflecting portion 36 is integrated with the light guide means 10. The reflecting portion 36 is preferably provided with a reflecting mirror coat. The luminous flux emitted from the light source 5 is
(1) In the short-axis direction cross section, by the fifth surface 15, the sixth surface 16, the first surface 11, the second surface 12, the ninth surface 21, and the tenth surface 22 of the light guiding means 10. The reflected light beam passes through the exit surface 18 and travels toward the document surface;
(2) The light beam once reflected by the exit surface 18 is reflected by the reflecting portion 36 and is separated into a light beam that passes through the exit surface 18 and travels toward the document surface. By these two light fluxes ((1), (2)), illumination can be radiated symmetrically with respect to the document surface.

  In addition, since the light guide means 10 and the reflection portion 36 are manufactured integrally, the positional relationship between the reflection surface (the emission surface 18) of the light guide means 10 and the reflection portion 36 can be set strictly, so that the document due to assembly errors can be set. Surface illuminance variation can be reduced.

Embodiment 7 FIG.
FIG. 13 is a diagram showing a cross-sectional shape in the long axis direction (main scanning direction) of the light guide means 10 used in the image reading apparatus according to Embodiment 7 of the present invention.

  In the light guide unit 10 of the seventh embodiment, a plurality of light sources 5 are arranged in the light source storage unit 20. By arranging a plurality of the light sources in this way, the illumination intensity can be improved. In addition, since the illumination can be brightened, the reading speed can be increased.

Embodiment 8 FIG.
FIG. 14 is a diagram showing a cross-sectional shape in the long axis direction (main scanning direction) of the light guide means 10 used in the image reading apparatus according to Embodiment 8 of the present invention.

  In the light guide unit 10 of the eighth embodiment, red, green, and blue light sources (5R, 5G, and 5B) are disposed in the light source storage unit 20. By arranging in this way, independent light sources of the three primary colors can be combined by the same light guide means 10.

  In the eighth embodiment, although three primary colors are shown, an infrared light source can be added as the fourth light source.

Embodiment 9 FIG.
FIG. 15B is a diagram showing a cross-sectional shape in the long axis direction (main scanning direction) of the light guide unit used in the image reading apparatus according to Embodiment 9 of the present invention.

  In the light guide section of the ninth embodiment shown in FIG. 15 (2), a plurality (101, 102, 103) of the light guide means 10 having the shapes shown in the first to eighth embodiments are arranged in the major axis direction. Is. The purpose of arranging a plurality of light guide means is to make the irradiation on the document surface by the connecting part of the individual light guide means and its peripheral part uniform with respect to the irradiation by other parts in the long axis direction. (FIG. 15 (1)).

  That is, the irradiation intensity by one light guide 10 and one light source 5 becomes weaker as it deviates from the portion corresponding to the light source 5 in the major axis direction (see FIG. 8). Therefore, by connecting a plurality of light guiding means as structural units, it is possible to prevent the irradiation intensity from being weakened even in the portion corresponding to the connecting portion in the long axis direction as shown in FIG. In this way, the document reading area can be lengthened, and thus a large document can be read. In addition, since the change of the irradiation intensity distribution due to scattering can be suppressed by maintaining the connection surface of the light guide means 10 with a transparent adhesive or a mirror surface, it is possible to ensure the uniformity of the irradiation intensity at the connection portion (this If the connecting surface is a sand surface or an uneven surface, the document surface illumination distribution near the connecting portion may not be uniform.)

  Conventionally, when reading a long document, a method of extending the light guide means to be equal to or greater than the width of the document has been used. However, this method has a limit in the number of light sources and illuminance that can be used even when the reading area becomes long, and it is difficult to obtain sufficient illumination illuminance.

  According to the present embodiment, light guide means (as a constituent unit) integrated with the light source may be arranged in accordance with the length of the document reading area. By doing so, the illumination illuminance on the document surface is kept substantially constant in the major axis direction. There is no difficulty in reading long documents.

  For example, if ten light guides having a length of 30 mm in the long axis direction are arranged, uniform illumination of a 300 mm area is possible, that is, reading of an A3 size document is possible.

Embodiment 10
FIG. 16B is a diagram illustrating a cross-sectional shape in the major axis direction (main scanning direction) of the light guide unit used in the image reading apparatus according to the tenth embodiment of the present invention.

  In the ninth embodiment, a plurality of individual light guide means 10 are connected, whereas in the eleventh embodiment, a light guide portion corresponding to the plurality of light guide means is manufactured by integral molding. As a result, the number of parts can be reduced and the assembly accuracy can be improved in the image reading apparatus.

  When reading a very large document, a plurality of the light guides may be connected.

  FIG. 17 shows an example of ray tracing simulation when the light guide means 10 according to the tenth embodiment is used. It is well understood that there is no deviation in the light irradiation angle on the document surface.

  FIG. 18 shows the calculation result of the document surface illuminance distribution in the case of the configuration. This calculation example shows the illuminance at the document surface reading position in the main scanning direction in the central portion in the state where the length of the light guiding unit 10 in the main scanning direction is 32 mm and the three light guiding units are integrally formed. It is. Compared to the illuminance of the direct illumination light beam, the illuminance of the reflected illumination light beam is ½ or more, and the illuminance distribution of the total illuminance light beam is within ± 10%.

  FIG. 19 shows the calculation result of the irradiation angle distribution at the original surface reading position of the original surface irradiation light beam. The irradiation angle of the direct illumination light beam is + 37 ° to + 72 °, and the irradiation angle of the reflected illumination light beam is −37 ° to −63 °.

FIG. 3 is a cross-sectional view in the minor axis direction (sub-scanning direction) of the image reading apparatus according to Embodiment 1 of the present invention. 1 is a perspective view of a part of an image reading apparatus according to Embodiment 1 of the present invention. In the image reading apparatus according to the first embodiment, a simulation example of an angular distribution of light irradiated on a document surface is shown. It is sectional drawing of the short axis direction (sub scanning direction) of the image reading apparatus which concerns on Embodiment 2 of this invention. It is sectional drawing of the short axis direction (sub-scanning direction) of the image reading apparatus which concerns on Embodiment 3 of this invention. It is a major axis direction (main scanning direction) sectional view of a light guide used in an image reading apparatus according to Embodiment 4 of the present invention. FIG. 10 is a longitudinal cross-sectional view of a light guiding unit that can be assumed as a comparative example of the fourth embodiment. It is an example of the illuminance distribution on the document surface in the long axis direction in the conventional image reading apparatus. 10 is an example of an illuminance distribution on a document surface in a major axis direction in an image reading apparatus according to a fourth embodiment. It is a short axis direction (sub-scanning direction) sectional view of a light guide used in an image reading apparatus according to Embodiment 5 of the present invention. FIG. 10 is a short-axis direction cross-sectional view of a light guiding unit that can be assumed as a comparative example of the fifth embodiment. It is sectional drawing of the short-axis direction of the light guide means of the image reading apparatus which concerns on Embodiment 6 of this invention. It is a figure which shows the major axis direction (main scanning direction) cross-sectional shape of the light guide means utilized with the image reading apparatus which concerns on Embodiment 7 of this invention. It is a figure which shows the major-axis direction (main scanning direction) cross-sectional shape of the light guide means utilized with the image reading apparatus which concerns on Embodiment 8 of this invention. (1) is the light intensity distribution in the major axis direction of the document reading area formed by the image reading apparatus according to Embodiment 9 of the present invention. (2) is a diagram showing a cross-sectional shape in the long axis direction (main scanning direction) of the light guide used in the image reading apparatus according to Embodiment 9 of the present invention. (1) is the light intensity distribution in the major axis direction of the document reading area formed by the image reading apparatus according to Embodiment 10 of the present invention. (2) is a diagram showing a cross-sectional shape in the long axis direction (main scanning direction) of the light guide used in the image reading apparatus according to Embodiment 10 of the present invention. An example of ray tracing simulation in the case of using the light guide unit according to the tenth embodiment will be described. The calculation result of the document surface illuminance distribution in the case of using the light guiding means according to the tenth embodiment is shown. The calculation result of the irradiation angle distribution in the original surface reading position of the original surface irradiation light beam when using the light guide unit according to the tenth embodiment is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Case, 2 Glass, 3 Original, 4 Platen, 5 Light source, 6 Rod lens array, 7 Line sensor IC, 8 Sensor substrate, 9 Light source substrate, 10 Light guide means, 11 1st surface, 12 2nd surface , 13 3rd surface, 14 4th surface, 15 5th surface, 16 6th surface, 17 light incident surface, 18 light emitting surface, 20 light source accommodating portion, 35 reflecting portion.

Claims (10)

One or more light sources for illuminating the document surface;
A light guide means having a light entrance surface and a light exit surface for entering and exiting light so that the light emitted from the light source travels into the transparent member and is guided to a linear reading target region;
An optical system for collecting the light reflected from the document surface;
In an image reading apparatus provided with an image forming unit of the optical system and including a sensor for reading an image of the document,
The light guide means includes a light source storage portion having a substantially rectangular light emission surface that is long in the major axis direction of the linear reading target region on the upper surface, and a light source storage portion on which the light source is installed on the lower surface, and the wall surface of the light source storage portion Is the light incident surface,
The side surface of the light guide means has a first surface and a second surface across the thickness of the light guide means in the short axis direction parallel to the long axis direction of the light guide means, and the light guide means A seventh surface and an eighth surface across the major axis thickness of the light guide means in parallel with the minor axis direction of
About the short axis direction of the linear reading area
The light emitted from the light source, incident on the light incident surface of the light guide means through the light source housing, is reflected by the first surface and the second surface, and is guided to the light emitting surface. While leading to a linear reading target area,
A linear reading target region is provided by providing a reflecting surface for reflecting a part of the light emitted from the light emitting surface of the light guide, with an optical system for collecting the light reflected from the document surface being separated. An image reading apparatus characterized by having a structure that leads to   Of the light emitted from the light exit surface of the light guide, by bending the first surface and the second surface of the light guide means to form a ninth surface and a tenth surface, The ratio of the amount of light directly guided to the linear reading target area and the amount of light reflected directly by the reflecting plate and directly guided to the linear reading target area is adjusted so as to obtain approximately the same amount of light. The image reading apparatus according to claim 1.   The image reading apparatus according to claim 1, wherein the light source and the sensor are arranged on the same substrate. Having a third surface and a fourth surface extending in parallel to the short axis direction of the light guide means and extending from the vicinity of the light source storage portion on the bottom surface of the light guide means to the seventh surface and the eighth surface;
About the long axis direction of the linear reading area
Of the light emitted from the light source and incident from the light incident surface of the light guide means through the light source housing, most of the light having an angle that is totally reflected by the light exit surface of the light guide means is 4. The image reading apparatus according to claim 1, wherein the image reading apparatus is configured to be reflected by the third surface and the fourth surface and guided to the light emitting surface. 5. About the first surface and the second surface of the light guide means,
Of the light emitted from the light source and incident from the light incident surface of the light guide means through the light source housing, most of the light having an angle that is not totally reflected by the first surface and the second surface. 5. The image reading apparatus according to claim 1, further comprising a fifth surface and a sixth surface that are totally reflected and led to the light emitting surface. A transparent member is filled between the light emitting surface and the reflecting surface of the light guide means,
A reflective surface is formed on the surface of the transparent member,
The image reading apparatus according to claim 1, wherein the transparent member and the light guide unit are integrally formed. 6. The image reading apparatus according to claim 1, wherein a plurality of light sources are housed as light sources in the light source housing section of the light guide unit.   The image reading apparatus according to claim 1, wherein a light source that emits red, green, and blue light is housed as a light source in the light source housing portion of the light guide unit. .   The image reading apparatus according to claim 1, wherein the light guide unit is connected in a major axis direction. The image reading apparatus according to claim 9, wherein the plurality of connected light guides are integrally formed for the whole or a part of the reading region.

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