JP2015082795A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader which has a luminaire capable of reducing light quantity loss.SOLUTION: An image reader comprises: a luminaire 50 for illuminating scripts; and an image sensor for receiving reflective light from scripts and converting the reflective light into an image signal, the luminaire comprises: a plurality of light emitting elements 100; and a light guide body 102 for guiding light emitted to the emission direction E from light emitting parts 108 of a plurality of light emitting elements toward scripts 203, and the light guide body comprises: an incidence surface 103 where the light from a plurality of light emitting elements enters; a light guide part 104 for propagating the light 107 entered to the incidence surface 103; an emission surface 106 for emitting the light propagated by the light guide part toward scripts; eaves 110 extending from the light guide part to a direction opposite to the emission direction on a plurality of light emitting elements; and a reflective part 111 for reflecting a part of the light entering to the incidence surface 103 and a part of the light entering to eaves from a plurality of light emitting elements toward the light guide body.

Description

  The present invention relates to an image reading apparatus having an illumination device that illuminates a document.

  Conventionally, an image reading apparatus is used for a copying machine, an image scanner, a multifunction printer, and the like. The image reading device illuminates the original with light and receives reflected light from the original to read an image on the original. In order to illuminate a document with light, the image reading apparatus includes an illumination device. Some illumination devices include a light guide that guides light emitted from a plurality of light emitting elements to a document.

  FIG. 6 is a cross-sectional view showing a sub-scanning cross section of the conventional illumination device 450. The illuminating device 450 is disposed under the document table glass 202 on which the document 203 is placed.

  The lighting device 450 includes a plurality of light emitting elements 100, a substrate 101 on which the plurality of light emitting elements 100 are arranged, and a light guide body 402 fixed to the substrate 101. The plurality of light emitting elements 100 are linearly arranged on the substrate 101 along the main scanning direction (direction perpendicular to the paper surface of FIG. 6). The light guide 402 has an incident surface 403, a light guide 404, a deflection surface (reflection surface) 405, and an exit surface 406. The incident surface 403 of the light guide 402 is disposed in the vicinity of the light emitting portion (emission surface) 108 of the light emitting element 100.

  In the lighting device 450 illustrated in FIG. 6, the light 107 emitted from the light emitting unit 108 of the light emitting element 100 enters the incident surface 403 of the light guide 402. The light 107 propagates in the light guide unit 404 of the light guide 402. The deflecting surface 405 deflects the traveling direction of the light 107 from the light guide unit 404 upward, and directs the light 107 to the document reading position RP on the document table glass 202. The light 107 illuminates the original 203 placed on the upper surface 202a of the original table glass 202 in a straight line in the main scanning direction.

  Most of the light 107 from the light emitting element 100 is incident on the incident surface 403 of the light guide 402. However, since the light emitting element 100 emits the light 107 with a Gaussian distribution, a part of the light 114 incident on the incident surface 403 is guided without satisfying the condition of total reflection in the light guide unit 404. It leaks out of the part 404.

  There is also light 115 leaking from the top surface 100 a other than the light emitting portion 108 of the light emitting element 100. Since the lights 114 and 115 are not the desired illumination light 107, the lights 114 and 115 are harmful lights that cause problems such as making the amount of illumination uneven and causing ghosts and flares in the read image.

  In order to prevent illumination failure and image failure due to these harmful lights 114 and 115, the illumination device 450 includes a light shielding member 109 that covers a part of the light guide 402 and the light emitting element 100 as shown in FIG. (Patent Document 1). The light shielding member 109 blocks the harmful lights 114 and 115 so that the harmful lights 114 and 115 do not reach the document reading position RP.

JP 2008-180841 A

  The light shielding member 109 is generally made of a sheet member or an opaque resin member. Since the light emitting element 100 is a heating element, the light shielding member 109 covering the light emitting element 100 is required to have heat resistance. However, when a heat-resistant sheet member or a heat-resistant opaque resin member is used for the light shielding member 109, there is a problem that the manufacturing cost of the lighting device 450 is increased.

  In addition, a part of the light 114 and 115 of the light 107 emitted from the light emitting element 100 leaks out of the light guide 402, which causes a problem of causing a light amount loss of illumination light.

  Accordingly, the present invention provides an image reading apparatus having an illumination device that can reduce light loss.

In order to solve the above problem, an image reading apparatus according to the present invention provides:
An illumination device for illuminating the document;
An image sensor that receives reflected light from the document and converts the reflected light into an image signal;
Have
The lighting device includes:
A plurality of light emitting elements;
A light guide for directing light emitted in the emission direction from the light emitting portions of the plurality of light emitting elements to the document;
Have
The light guide is
An incident surface on which the light from the plurality of light emitting elements is incident;
A light guide that propagates the light incident on the incident surface;
An exit surface that emits the light propagating through the light guide unit toward the document;
A collar portion extending on the plurality of light emitting elements in a direction opposite to the emission direction from the light guide,
A reflection unit that reflects a part of the light incident on the incident surface and a part of the light incident on the flange from the plurality of light emitting elements toward the light guide unit;
Have

  ADVANTAGE OF THE INVENTION According to this invention, the image reader which has an illuminating device which can reduce light quantity loss can be provided.

FIG. 3 shows a lighting device according to Embodiment 1. FIG. 6 is a partial cross-sectional view of a light guide body according to a second embodiment. FIG. 6 is a partial cross-sectional view of a light guide body according to a third embodiment. FIG. 3 is a cross-sectional view of the optical unit according to the first embodiment. FIG. 3 is a cross-sectional view of the image reading apparatus according to the first exemplary embodiment. Sectional drawing which shows the sub-scanning cross section of the conventional illuminating device.

  Examples of the present invention will be described below.

  Example 1 will be described below.

(Image reading device)
FIG. 5 is a cross-sectional view of the image reading apparatus 207 according to the first embodiment.
The image reading device 207 includes a main body 208, an original table glass 202 disposed on the upper portion of the main body 208, and an optical unit 200 that can move in the sub-scanning direction Y inside the main body 208. The optical unit 200 is supported by a track 209 provided in the main body 208. The optical unit 200 is fixed to a belt 210 wound around a pair of pulleys 211 and 212. The motor 213 rotates the pulley 211 in the forward and reverse directions to rotate the belt 210 in the directions indicated by the arrows C1 and C2. When the belt 210 is rotated forward in the direction indicated by the arrow C <b> 1 by the motor 213, the optical unit 200 moves in the sub-scanning direction Y along the track 209. On the other hand, when the belt 210 is reversely rotated by the motor 213 in the direction indicated by the arrow C2, the optical unit 200 moves in the direction opposite to the sub-scanning direction Y.

  The optical unit 200 reads an image of the original 203 while moving in the sub-scanning direction Y under the original table glass 202 on which the original 203 is placed. Here, the sub-scanning direction Y is orthogonal to the main scanning direction X (FIG. 1B). The main scanning direction X is a direction (a direction perpendicular to the paper surface of FIG. 5) in which a plurality of light receiving units of an individual imaging element (image sensor) 206 described later of the optical unit 200 is arranged. In other words, the individual image sensor 206 converts the image of the original 203 into an image signal in a line shape in the main scanning direction X.

(Optical unit)
FIG. 4 is a cross-sectional view of the optical unit 200 according to the first embodiment.
The optical unit 200 includes a frame body 214, an illumination device 50, reflection mirrors 204 (204 a, 204 b, 204 c, and 204 d), a lens unit (imaging optical system) 205, and an individual image sensor 206. The housing member 201 is provided on the upper part of the frame body 214. The lighting device 50 is fixed to the housing member 201. The plurality of reflection mirrors 204 and the lens unit 205 are arranged in the frame body 214. The individual imaging element 206 is fixed to the side portion of the frame body 214.

  The illuminating device 50 illuminates the original 203 on the original table glass 202 linearly in the main scanning direction X. An LED light beam (hereinafter referred to as light) 107 emitted from the illumination device 50 is reflected by the original 203 on the original table glass 202. The reflected light 117 enters the frame body 214 through the light transmission part 201 a of the housing member 201 and the light transmission part 214 a of the frame body 214. The reflected light 117 is reflected by the reflecting mirrors 204 a, 204 b, 204 c, and 204 d and enters the lens unit 205. The lens unit 205 forms an image of the reflected light 117 on the individual imaging element 206 through the light transmission part 214 b of the frame body 214. The individual imaging element 206 has a plurality of light receiving units arranged in the main scanning direction X. The solid-state imaging device 206 receives the reflected light 117 and photoelectrically converts the reflected light 117 into an electrical signal as an image signal according to linear image information in the main scanning direction X of the document 203.

  The optical unit 200 reads a planar image of the original 203 by sequentially outputting linear image information in the main scanning direction X as an electric signal while moving in the image scanning device 207 in the sub-scanning direction Y. It is configured.

(Lighting device)
FIG. 1 is a diagram illustrating an illumination device 50 according to the first embodiment. FIG. 1A is a cross-sectional view showing a sub-scanning cross section of the illumination device 50. FIG. 1B is a plan view of the lighting device 50.

  The lighting device 50 includes a plurality of light emitting diodes (hereinafter referred to as light emitting elements) 100, an LED printed wiring board (hereinafter referred to as a substrate) 101 in which the plurality of light emitting elements 100 are arranged in an array, and fixed to the substrate 101. Light guide 102.

  In this embodiment, an edge-emitting light emitting diode is used as the light emitting element 100. However, a surface emitting light emitting diode may be used as the light emitting element 100. The plurality of light emitting elements 100 are arranged on the substrate 101 in a straight line along the arrangement direction (main scanning direction X shown in FIG. 1B) at a predetermined interval.

  The light guide 102 has an incident surface 103, a light guide unit 104, a deflection surface (reflection surface) 105, and an exit surface 106. In the present embodiment, the light guide 102 is formed of a transparent resin material such as acrylic resin. The light guide 102 has an elongated shape in the main scanning direction X. The incident surface 103 on the upstream side in the sub-scanning direction Y of the light guide 102 is arranged along the plurality of light emitting elements 100 arranged in a straight line. The incident surface 103 is disposed in the vicinity of the light emitting portion (emission surface) 108 of the light emitting element 100 in order to reduce the light amount loss of light from the light emitting element 100. An upper surface (hereinafter referred to as a contact surface) 101 a of the substrate 101 is substantially parallel to the emission direction E of the light 107 emitted from the plurality of light emitting elements 100. The light guide 102 is fixed to the substrate 101.

  Light 107 emitted from the light emitting unit 108 of the light emitting element 100 enters the incident surface 103 of the light guide 102. The light 107 incident on the incident surface 103 propagates through the light guide unit 104 of the light guide 102. A deflecting surface 105 for directing light 107 to the original 203 is provided between the light guide unit 104 and the exit surface 106 of the light guide 102. The deflection surface 105 deflects (reflects) the light 107 obliquely upward as shown in FIG. The deflected light 107 is emitted obliquely from the emission surface 106 on the downstream side in the sub-scanning direction Y of the light guide 102 to the document reading position RP on the document table glass 202. Light 107 from the illumination device 50 illuminates the document 203 linearly in the main scanning direction X at the document reading position RP.

(Light guide)
The light guide 102 directs the light 107 emitted in the emission direction E from the light emitting units 108 of the plurality of light emitting elements 100 toward the document 203. In the present embodiment, the emission direction E is a direction perpendicular to the main scanning direction X. The emission direction E is inclined with respect to the sub-scanning direction Y, but may be parallel to the sub-scanning direction Y.

  Referring to FIG. 1A, the light guide 102 has a flange 110 that extends from the upper part of the incident surface 103 in a direction opposite to the emission direction E (upstream side in the sub-scanning direction Y). The flange 110 covers the top surface 100 a of the light emitting element 100. A concave portion 118 is formed under the collar portion 110. The recess 118 houses the light emitting element 100. In the present embodiment, the flange portion 110 covers the light emitting element 100 over the entire length of the light emitting element 100 in the emission direction E. However, the collar portion 110 may cover a part of the length of the light emitting element 100 in the emission direction E.

  The light guide 102 has an inclined top surface (connection surface) 111 on the upper portion of the flange portion 110. In the present embodiment, the inclined top surface 111 is a flat inclined surface extending from the rear end portion 110 a of the flange portion 110 to the upper surface 104 a of the light guide portion 104. The inclined top surface 111 does not necessarily extend from the rear end portion 110 a of the flange portion 110, and may be provided at a part of the upper portion of the flange portion 110. The inclined top surface 111 is inclined with respect to the upper surface 104 a of the light guide unit 104. The inclined top surface 111 is an angle exceeding 180 ° at the ridge line portion 116 provided at a position away from the incident surface 103 of the light guide 102 by the distance D in the emission direction E of the light 107 emitted from the light emitting unit 108. It is configured to intersect the upper surface 104a of the light guide unit 104 at θ. That is, the angle θ formed between the inclined top surface 111 and the upper surface 104a of the light guide unit 104 is greater than 180 °.

  The light 107 emitted from the emission surface 108 of the light emitting element 100 generally has a Gaussian distribution. Therefore, in the conventional light guide 402, as shown in FIG. 6, a part of the light 114 incident on the incident surface 403 of the light guide 402 is not totally reflected by the light guide 404. It goes out of the light guide 404 as it is. On the other hand, according to the present embodiment, the light 114 is totally reflected by the inclined top surface 111 of the light guide 102 and guided to the light guide unit 104 as shown in FIG. Since the inclined top surface 111 can be set at an angle different from the upper surface 104 a of the light guide unit 104, the angle of the inclined top surface 111 can be set so that the light 114 is totally reflected by the inclined top surface 111.

  In general, most of the light 107 from the light emitting element 100 is incident on the incident surface 103 of the light guide 102. However, since the case of the light emitting element 100 itself also emits light as a whole, a part of the light 115 is emitted upward from the top surface 100a of the light emitting element 100 as shown in FIG.

  In the conventional light guide 402, as shown in FIG. 6, the light 115 emitted upward from the top surface 100 a of the light emitting element 100 does not enter the light guide 402 and goes to the outside of the light guide 402. Emitted. On the other hand, according to the present embodiment, the light 115 emitted upward from the top surface 100 a of the light emitting element 100 enters the flange 110 of the light guide 102. The light 115 incident on the collar portion 110 is totally reflected by the inclined top surface 111 of the light guide 102 and guided to the light guide portion 104 as shown in FIG. Since the inclined top surface 111 can be set to an angle different from the upper surface 104 a of the light guide unit 104, the angle of the inclined top surface 111 can be set so that the light 115 is totally reflected by the inclined top surface 111.

  In the prior art, the lights 114 and 115 are harmful lights that leak out of the light guide 402 and then go to the document reading position RP, causing poor illumination and poor images. On the other hand, in this embodiment, light 114 and 115 traveling from the light emitting element 100 to the document reading position RP is totally reflected by the inclined top surface 111 of the light guide 102. The inclined top surface 111 of the light guide 102 constitutes a reflecting portion that reflects the light 114 and 115 that travels from the light emitting element 100 toward the document reading position RP. Therefore, the light 114 and 115 can be prevented from leaking out of the light guide 102 from a portion other than the light exit surface 106 of the light guide 102.

  The lights 114 and 115 are totally reflected by the inclined top surface 111 of the light guide 102 and guided to the light guide unit 104, and are directed from the exit surface 106 of the light guide 102 to the document reading position RP. Therefore, according to the present embodiment, the lights 114 and 115, which are harmful lights in the prior art, can be used effectively as illumination lights. That is, the light emitted from the light emitting element 100 is guided by the light guide 102 without loss of light amount and irradiates the surface of the original 203. Since light loss is reduced, it is possible to increase the illumination efficiency and reduce the number of light emitting elements 100.

  The inclined top surface 111 is set to an angle that totally reflects the lights 114 and 115 from the light emitting element 100 toward the document reading position RP. In the present embodiment, the inclined top surface 111 extends to the rear end portion (end portion in the direction opposite to the emission direction E) 110a of the flange portion 110. However, as long as the light 114 and 115 can be totally reflected, the light does not necessarily extend to the rear end portion 110a.

  As a supplement, the tilted top surface 111 is a total of all of the light emitted from the top surface 100a of the light emitting element 100 to the tilted top surface 111 and the light emitted from the light emitting portion 108 of the light emitting element 100 to the tilted top surface. It cannot be reflected and directed to the light guide unit 104. For example, as illustrated in FIG. 1A, the light 121 emitted from the top surface 100 a of the light emitting element 100 may leak out of the light guide 102. However, since the light 121 is emitted from the light guide 102 at an angle that does not reach the document reading position RP, the light 121 does not become harmful light that causes illumination failure and image failure.

(Explanation of distance D)
The inclined top surface 111 is an angle exceeding 180 ° at the ridge line portion 116 provided at a position away from the incident surface 103 of the light guide 102 by the distance D in the emission direction E of the light 107 emitted from the light emitting unit 108. It is configured to intersect the upper surface 104a of the light guide unit 104 at θ.

  The ridge line portion 116 is positioned on the upper surface 104a of the light guide portion 104 so that the inclined top surface 111 is inclined at an angle at which the light 114 and 115 from the light emitting element 100 toward the document reading position RP can be totally reflected. The distance D is a distance in the emission direction E between the edge line portion 116 thus positioned and the incident surface 103.

  The ridge line portion 116 is provided on the upper surface of the light guide 102 between the incident surface 103 and the deflection surface 105 of the light guide 102. The ridge line part 116 is a connection part that connects the upper surface 104 a of the light guide part 104 and the inclined top surface 111. In the ridge line portion 116, the inclination angle of the upper surface 104 a of the light guide portion 104 is changed to form the inclined top surface 111. The ridge line portion 116 does not have to be linear, and may be curved. The ridgeline part 116 should just be provided in the intersection or the part corresponding to the intersection of the inclined top surface 111 set to the angle which can totally reflect the lights 114 and 115, and the upper surface 104a of the light guide part 104. FIG.

  In this embodiment, the light guide 102 is provided with one inclined top surface 111. However, the light guide 102 may be provided with a plurality of inclined top surfaces having different inclination angles. An inclined top surface that totally reflects light 114 incident on the incident surface 103 of the light guide 102 and traveling toward the document reading position RP, and an inclined top surface that totally reflects light 115 traveling from the top surface 100a of the light emitting element 100 toward the document reading position RP. You may provide a surface in the light guide 102 separately.

  According to the present embodiment, the light traveling from the light emitting element 100 toward the document reading position RP can be shielded by the inclined top surface 111. Accordingly, it is possible to prevent illumination failure due to uneven illumination light quantity and image failure due to ghost or flare.

  Further, according to the present embodiment, the light traveling from the light emitting element 100 to the document reading position RP can be totally reflected by the inclined top surface 111 and propagated to the exit surface 106 of the light guide 102. Therefore, it is possible to reduce the light amount loss, increase the amount of illumination light, and reduce the number of light emitting elements 100. As a result, the manufacturing cost of the image reading apparatus can be reduced.

Example 2 will be described below.
Since the image reading device, the optical unit, and the illumination device of the second embodiment are the same as those of the first embodiment, description thereof is omitted. Since the light guide 122 of the second embodiment is different from the light guide 102 of the first embodiment, the light guide 122 will be described below with reference to FIG.

  FIG. 2 is a partial cross-sectional view of the light guide 122 according to the second embodiment. In FIG. 2, the same reference numerals are given to the same structures as those of the first embodiment, and the description thereof will be omitted.

  The flange portion 110 of the light guide 122 covers the upper surface 100 a of the light emitting element 100. The light guide 122 has an inclined top surface (connection surface) 131 on the upper portion of the flange 110. In the present embodiment, the inclined top surface 131 is a flat inclined surface extending from the rear end portion 110 a of the collar portion 110 to the upper surface 104 a of the light guide portion 104. The inclined top surface 131 does not necessarily extend from the rear end portion 110 a of the flange portion 110, and may be provided at a part of the upper portion of the flange portion 110. The inclined top surface 131 is inclined with respect to the upper surface 104 a of the light guide unit 104. A white or silver reflective paint (reflective portion) 132 is applied to the inclined top surface 131 of the light guide 122.

  In the first embodiment, in order for total reflection to occur stably, the angle of light incident on the inclined top surface 111 as the reflecting portion is limited (critical angle). However, as shown in the second embodiment, by applying the reflective coating 132 to the inclined top surface 131, it is possible to loosen the restriction on the angle of light incident on the inclined top surface 131.

  The upper surface 104 a of the light guide unit 104 and the inclined top surface 131 intersect at the ridge line part 126. The ridge line portion 126 is a connection portion that connects the upper surface 104 a of the light guide unit 104 and the inclined top surface 131. The ridge line portion 126 is provided on the upper surface of the light guide 102 between the incident surface 103 and the deflection surface 105 of the light guide 122. The inclined top surface 131 is configured to intersect the upper surface 104a of the light guide unit 104 at an angle θ1 exceeding 180 ° at the ridge line portion 126. That is, the angle θ1 formed between the inclined top surface 131 and the upper surface 104a of the light guide unit 104 is greater than 180 °.

  The light 114 incident on the incident surface 103 from the light emitting portion 108 of the light emitting element 100 and traveling toward the document reading position RP and the light 115 incident on the collar portion 110 from the top surface 100a of the light emitting element 100 and traveling toward the document reading position RP are reflected paint. Reflected by the inclined top surface 111 to which 132 is applied. Therefore, the angle θ1 between the inclined top surface 131 and the upper surface 104a of the light guide unit 104 is not necessarily set to an angle exceeding 180 ° so as to satisfy the condition of total reflection. For example, the angle θ1 is 180 °. Also good.

  Further, since the inclined top surface 131 does not need to be set to an angle at which the light 114 and 115 are totally reflected, the distance D from the incident surface 103 to the ridge line portion 126 may not be limited. The ridge line portion 126 only needs to be provided between the incident surface 103 and the deflection surface 105 of the light guide 122.

  A reflective coating 132 is applied to the inclined top surface 131 on the opposite side of the collar portion 110 from the light emitting element 100. Since the reflective paint 132 is provided away from the light emitting element 100, a paint having a relatively low heat resistance can be used as the reflective paint 132. Therefore, the manufacturing cost can be reduced.

  In the second embodiment, the same effect as that of the first embodiment can be obtained.

Example 3 will be described below.
Since the image reading device, the optical unit, and the illumination device of the third embodiment are the same as those of the first embodiment, description thereof is omitted. Since the light guide 142 of the third embodiment is different from the light guide 102 of the first embodiment, the light guide 142 will be described below with reference to FIG.

  FIG. 3 is a partial cross-sectional view of the light guide 142 according to the third embodiment. In FIG. 3, the same reference numerals are assigned to the same structures as those of the first embodiment, and the description thereof is omitted.

  The collar portion 110 of the light guide 142 covers the upper surface 100 a of the light emitting element 100. The light guide 142 has an inclined top surface (connection surface) 141 on the upper portion of the flange 110. In the present embodiment, the inclined top surface 141 is a flat inclined surface extending from the rear end portion 110 a of the flange portion 110 to the upper surface 104 a of the light guide portion 104. The inclined top surface 141 does not necessarily extend from the rear end portion 110a of the flange portion 110, and may be provided at a part of the upper portion of the flange portion 110. The inclined top surface 141 is inclined with respect to the upper surface 104 a of the light guide unit 104. A reflective sheet member (reflective portion) 143 is disposed on the inclined top surface 141 of the light guide 122.

  In the first embodiment, in order for total reflection to occur stably, the angle of light incident on the inclined top surface 111 as the reflecting portion is limited (critical angle). However, as shown in Example 3, by disposing the reflective sheet member 143 on the inclined top surface 141, it is possible to loosen the limit of the angle of light incident on the inclined top surface 141.

  The upper surface 104 a of the light guide unit 104 and the inclined top surface 141 intersect at the ridge line part 146. The ridge line portion 146 is a connection portion that connects the upper surface 104 a of the light guide unit 104 and the inclined top surface 141. The ridge portion 146 is provided on the upper surface of the light guide 142 between the incident surface 103 and the deflection surface 105 of the light guide 142. The inclined top surface 141 is configured to intersect the upper surface 104a of the light guide unit 104 at an angle θ2 exceeding 180 ° at the ridge line portion 146. That is, the angle θ2 formed by the inclined top surface 141 and the upper surface 104a of the light guide unit 104 is greater than 180 °.

  The light 114 incident on the incident surface 103 from the light emitting unit 108 of the light emitting element 100 and traveling toward the document reading position RP and the light 115 incident on the collar 110 from the top surface 100a of the light emitting element 100 and traveling toward the document reading position RP are reflected sheets. Reflected by the inclined top surface 141 on which the member 143 is disposed. Therefore, the angle θ2 between the inclined top surface 141 and the upper surface 104a of the light guide unit 104 does not necessarily need to be set to an angle exceeding 180 ° so as to satisfy the condition of total reflection. Also good.

  In addition, the inclined top surface 141 does not need to be set to an angle at which the light 114 and 115 are totally reflected, and therefore the distance D from the incident surface 103 to the ridge line portion 146 does not have to be limited. The ridge line portion 146 only needs to be provided between the incident surface 103 and the deflecting surface 105 of the light guide 142.

  A reflective sheet member 143 is disposed on the inclined top surface 141 opposite to the light emitting element 100 of the collar portion 110. Since the reflective sheet member 143 is disposed away from the light emitting element 100, a material having a relatively low heat resistance can be used as the reflective sheet member 143. Therefore, the manufacturing cost can be reduced.

  Also in Example 3, the same effect as Example 1 can be produced.

  In the first to third embodiments, the image reading device 207 operating in the fixed reading mode for reading the image of the document 203 on the platen glass 202 while moving the optical unit 200 in the sub-scanning direction Y has been described. In the fixed reading mode, the illuminating device 50 illuminates the original 203 linearly in the main scanning direction X in which the solid-state image sensor 206 converts the image of the original 203 into a linear image signal. The image reading device 207 reads the image of the document 203 while moving the illumination device 50 and the individual imaging element 206 in the sub-scanning direction Y orthogonal to the main scanning direction X.

  The image reading apparatus 207 may have a flow reading mode in which the optical unit 200 is stopped at the reading position, and the image of the original 203 is read while moving the original 203 in the sub-scanning direction Y on the reading position. In the flow-reading mode, the illumination device 50 illuminates the document 203 linearly in the main scanning direction X. The image reading device 207 reads the image of the document 203 while moving the document 203 in the sub-scanning direction Y orthogonal to the main scanning direction. The illumination device 50 can achieve the same effect as that in the fixed reading mode even in the flow reading mode.

DESCRIPTION OF SYMBOLS 50 Illuminating device 100 Light emitting element 102,122,142 Light guide 103 Incidence surface 104 Light guide part 106 Output surface 107 Light 108 Light emission part 110 Gutter part 111 Inclined top face (reflection part)
114, 115 Light 117 Reflected light 132 Reflective paint (reflective part)
143 Reflective sheet member (reflective part)
203 Document 206 Individual image sensor (image sensor)
207 Image reader E Emission direction

Claims (8)

An illumination device for illuminating the document;
An image sensor that receives reflected light from the document and converts the reflected light into an image signal;
An image reading apparatus comprising:
The lighting device includes:
A plurality of light emitting elements;
A light guide for directing light emitted in the emission direction from the light emitting portions of the plurality of light emitting elements to the document;
Have
The light guide is
An incident surface on which the light from the plurality of light emitting elements is incident;
A light guide that propagates the light incident on the incident surface;
An exit surface that emits the light propagating through the light guide unit toward the document;
A collar portion extending on the plurality of light emitting elements in a direction opposite to the emission direction from the light guide,
A reflection unit that reflects a part of the light incident on the incident surface and a part of the light incident on the flange from the plurality of light emitting elements toward the light guide unit;
An image reading apparatus.   The reflecting portion has an inclined top surface provided on an upper portion of the flange portion, and the inclined top surface extends from the part of the light incident on the incident surface and the plurality of light emitting elements to the flange portion. The image reading apparatus according to claim 1, wherein the part of the incident light is totally reflected toward the light guide unit.   2. The image reading apparatus according to claim 1, wherein the reflection portion includes an inclined top surface provided on an upper portion of the collar portion, and a reflective paint applied to the inclined top surface.   The image reading apparatus according to claim 1, wherein the reflection unit includes an inclined top surface provided on an upper portion of the flange portion, and a reflective sheet member disposed on the inclined top surface.   5. The image reading apparatus according to claim 2, wherein an angle formed between the inclined top surface and the upper surface of the light guide unit exceeds 180 °. The light guide further includes a deflection surface that deflects the light propagating through the light guide toward the document,
6. The image reading apparatus according to claim 2, wherein a connection portion that connects the inclined top surface and the upper surface of the light guide portion is provided between the incident surface and the deflection surface. 7. . The illuminating device illuminates the original in a line in the main scanning direction,
The image reading device according to claim 1, wherein the image reading device reads the image of the document while moving the illumination device and the image sensor in a sub-scanning direction orthogonal to the main scanning direction. apparatus. The illuminating device illuminates the original in a line in the main scanning direction,
The image reading apparatus according to claim 1, wherein the image reading apparatus reads the image of the document while moving the document in a sub-scanning direction orthogonal to the main scanning direction.

Images