JP2012160868A - Lighting system and image reader using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting system in which variation of light quantity distribution of the lighting system does not exist and a lighting spot, especially, a light quantity spot is difficult to occur in an image which is read in an image reader by deciding a forming position of a projection locked in a frame body of a light guide body.SOLUTION: The lighting system includes a light source and the light guide body. The light source is arranged to confront with at least on one end face of the light guide body. The light guide body includes an end face, a diffusion reflection face and a light emission face. The light emission face is formed of a circumference face. The diffusion reflection face is formed in a position where an optical axis normal which passes through a center of a circle forming a circumference face and is emitted from the light emission face. The system includes the frame body storing the light guide body. The light guide body forms the projection locked to the frame body on a side face following the optical axis normal which the diffusion reflection face forms and along a lighting line direction. One end being the tip of a light source side of the projection is formed between a light source side end face of the diffusion reflection face and a light source side end face in a lighting line of a lighting region.

Description

The present invention relates to an illumination device that is optimal as a light source for an image reading device such as a scanner device, a copying machine, or a facsimile, and relates to an improvement of a light source unit that uses a light guide mounted on the irradiation device.

In general, as an image reading apparatus of this type, for example, as disclosed in Patent Document 1, a document placed on a reading platen is irradiated with light from a light source unit of an illuminating device, and the reflected light is converted by a photoelectric conversion sensor. An image reading apparatus that receives light and reads an image is known.

The illumination device mounted on the image reading device disclosed in Patent Document 1 includes a light source unit and a photoelectric conversion sensor mounted on a scanning carriage that moves along a reading platen, and emits light emitted from the light source unit. The reflected light is received by the photoelectric conversion sensor. The photoelectric conversion sensor is constituted by a line sensor, and the image on the platen is read in line order while moving in the sub-scanning direction in which the scanning carriage moves perpendicular to the main scanning direction read by the photoelectric conversion sensor.

The light source unit used as the light source of the illuminating device is composed of a light source of a white LED serving as a light emission source, and a light guide serving as a rod-shaped light emitter by uniformly diffusing light from the light source in the main scanning direction. In this case, it is required to irradiate uniform light in the direction (arrangement direction of the line sensor).

For this reason, the light source unit is formed in a bar shape in which the light guide is formed in a scanning direction so that the diffuse reflection surface and the light emission surface are opposed to each other, and the light guide is stored in the exterior cover, with one end portion of the exterior cover. The light source is disposed on the one end surface of the light guide housed in the outer cover and the light source is opposed to each other with a predetermined gap, and the other end surface is not described but forms a reflection surface as a pseudo light source, In this case, the light emitted from the light guide toward the reading platen is uniform.

In addition, by providing a gradient to the inner surface of one end of the exterior cover to which the light source is attached, the exterior cover itself is used as a reflector that guides the light from the light source to the light guide, so that the light efficiently enters the light guide. Like.

Further, the image reading apparatus disclosed in Patent Document 1 described above includes a so-called close-contact optical system in which a cell hook lens is provided for each sensor of the line sensor. In the case of a so-called optical reduction type image reading apparatus using a condensing lens, such as an image reading apparatus, the amount of light at both ends in the main scanning direction of the reading area decreases according to the cosine fourth law by the condensing lens. The gap between the light body and the light source and the position of the light source facing the light guide are adjusted, and the light amount distribution characteristics on the irradiation surface (reading surface) are devised to increase in advance by the light amount attenuated by the cosine fourth law. .

Therefore, the characteristic management of the light amount distribution of the illumination device using the light guide varies depending on the application, and particularly when used as the illumination device of the image reading device, as described above, in the illumination device of Patent Document 1, the light guide is used. The light that illuminates the reading platen is controlled so as to be uniform linear light. In the illumination device of Patent Document 2, the light that radiates from the light guide and illuminates the reading platen is at both ends of the reading region in the main scanning direction. The end face of the light guide housed in the exterior cover must be managed so that the light quantity of the part becomes higher linear light than the center part, and as a condition for maintaining the linear light state by the preset light quantity distribution It is indispensable to consider in advance at the design stage the maintenance of a predetermined gap between the light source and the light source, the arrangement of the light source with respect to the end face of the light guide, the shape of the light guide, the light directivity of the light source, and the like.

Republished patent WO08 / 013234 JP 2010-193360 A

By the way, in the illumination device using the light guide described above, the light source is opposed to the end face of the light guide, the light of the light source is reflected in the light guide, and the reflected light is taken out from the light guide as linear light. In the illuminating device that illuminates, the spectral characteristic of the linear light obtained easily changes depending on the state of the reflected light reflected by the end face of the light guide.

In addition, as disclosed in Patent Document 1 and Patent Document 2 described above, the light guide is generally housed in a white frame, and a light source is disposed on the end surface of the light guide via the frame. It has become.

The frame body is arranged near the base end portion of the light guide body so that the light guide body housed in the frame body does not come off the frame body and the end face of the light guide body facing the light source does not float from the frame body. And a projection for locking.

However, the projection for locking with the frame provided in the vicinity of the base end portion of the light guide body becomes a factor that changes the state of the reflected light described above, and as a result, the spectral characteristics of the linear light change. As a result, an appropriate spectral characteristic cannot be obtained, and illumination spots are generated in the illumination light of the illumination device. When this illumination device is used as a light source of an image reading device, the illumination spots become a light amount unevenness of the read image. There is a problem that proper image reading processing cannot be performed.

In view of the above problems, the present invention provides an illumination device that suppresses illumination spots by modifying the support method of the light guide and the light source, and the image reading apparatus hardly causes unevenness in the read image. Is the issue.

To achieve the above object, in the illumination device according to claim 1 of the present invention, a light source, a light guide that guides light from the light source along the illumination line direction and illuminates the illumination area as linear light, and The light source is disposed opposite to at least one end surface of the light guide, and the light guide has an end surface for taking in light, a diffuse reflection surface for diffusing and reflecting the light taken in from the end surface, and a diffusion A light exit surface for emitting light diffusely reflected by the reflective surface toward the irradiation surface, and the light exit surface is formed of a circumferential surface,
The diffuse reflection surface is an illuminating device that is disposed at a position that forms an optical axis normal that exits from the light exit surface through the center of a circle that forms the circumferential surface of the diffuse reflection surface. The light guide body is a side surface along the optical axis normal line formed by the diffuse reflection surface, and forms a protrusion locked to the frame body along the illumination line direction, One end, which is the end of the projection on the light source side, is formed between the light source side end surface of the diffuse reflection surface and the light source side end surface of the illumination line of the illumination area.

Moreover, in the illuminating device according to claim 2 of the present invention, the illuminating device according to claim 1, further comprising a reflector having a reflective surface that reflects light from the light source toward one end surface of the light guide, The light guide body is formed with a flange portion that abuts the reflector on one end surface thereof, the light source is attached to a circuit board on which the light source is mounted, and the reflector is formed by the flange portion of the light guide body and the circuit board. It is sandwiched and held at a predetermined interval between the light source and the light guide.

Moreover, in the illuminating device of Claim 3 of this invention, it is the illuminating device of Claim 2, It is provided with the holding member which clamps the said reflector with the collar part of the said light guide, and the said circuit board.

In the illumination device according to claim 4 of the present invention, in the illumination device according to claim 2 and 3, both of the circuit boards of the light guide have a common reference plane, and the light guide The diffuse reflection surface is held at a first position positioned from the common reference surface, the circuit board is positioned from the common reference surface, and the light source faces the one end surface of the light guide. The light guide and the circuit board are held by the holding member via the reflector.

Moreover, in the illuminating device according to claim 5 of the present invention, in the illuminating device according to claim 4, the common reference plane is provided in a unit frame constituting the illuminating device, and the light guide is supported by the unit frame. The diffuse reflection surface of the light guide is held at a first position positioned from the common reference surface via the frame.

According to a sixth aspect of the present invention, in the lighting device according to the fourth aspect, the common reference plane is provided on a unit frame constituting the lighting device, and the circuit board is positioned on the unit frame. The circuit board has a positioning support portion supported by the positioning portion of the unit frame.

Moreover, in the illuminating device according to claim 7 of the present invention, in the illuminating device according to claim 1, the light exit surface of the light guide is formed by a circumferential surface, and the diffuse reflection surface is a circumference thereof. The light source mounted on the circuit board is disposed on the optical axis normal line of the diffuse reflection surface, and is disposed at a position where an optical axis normal line exiting from the light exit surface passes through the center of the circle forming the surface. And disposed at a position displaced toward the light exit surface with respect to the center of the circle.

Moreover, in the illuminating device according to claim 8 of the present invention, in the illuminating device according to claim 1, the light emission surface of the light guide is formed by a circumferential surface, and the diffuse reflection surface is a circumference thereof. The light source mounted on the circuit board is disposed at a position where an optical axis normal line exiting from the light exit surface passes through the center of the circle forming the surface, and the light source mounted on the circuit board includes two first and second light sources. The first light source is disposed at a first position on the optical axis normal line of the diffuse reflection surface and displaced toward the light exit surface side with respect to the center of the circle, and the second light source is It is disposed at a second position on the normal axis of the optical axis and displaced toward the diffuse reflection surface with respect to the center of the circle.

Moreover, in the illuminating device according to claim 9 of the present invention, in the illuminating device according to claim 6, the first and second light sources are separated from each other by the reflector, and from one end surface of the light guide. The lights entering the light guide are separated from each other.

Further, in the image reading apparatus according to the tenth aspect of the present invention, a platen for placing a read original, a light source for illuminating the read original placed on the platen, and a read original illuminated by the light source. And a light receiving means for receiving the reflected light. The light source comprises the illumination device according to any one of claims 1 to 9.

The present invention has the following effects.

First, the illumination device according to claim 1 includes a light source and a light guide that guides light from the light source along an illumination line direction and illuminates the illumination area as linear light, and the light source Is disposed opposite to at least one end surface of the light guide, and the light guide diffuses and reflects the diffused reflection surface that diffuses and reflects the light captured from the end surface, and the diffuse reflection surface. A light exit surface for emitting the emitted light toward the irradiation surface, and the light exit surface is formed of a circumferential surface,
The diffuse reflection surface is an illuminating device that is disposed at a position that forms an optical axis normal that exits from the light exit surface through the center of a circle that forms the circumferential surface of the diffuse reflection surface. The light guide body is a side surface along the optical axis normal line formed by the diffuse reflection surface, and forms a protrusion locked to the frame body along the illumination line direction, One end of the protrusion on the light source side is formed between the light source side end surface of the diffuse reflection surface and the light source side end surface in the illumination line of the illumination region, so that the light source to the light guide The reflected light reflected at the base end of the incoming light is not disturbed by the protrusion, and the locking condition with the frame body is maintained. In particular, the light quantity on the light source side end face in the illumination line of the illumination area The variation in distribution is small, and illumination spots can be further suppressed.

Moreover, in the illuminating device according to claim 2, the illuminating device according to claim 1, further comprising a reflector having a reflecting surface that reflects light from the light source toward one end surface of the light guide, The light guide is formed with a flange that contacts the reflector on one end surface thereof, the light source is attached to a circuit board on which the light source is mounted, and the reflector is sandwiched between the flange of the light guide and the circuit board By holding the light source and the light guide at a predetermined interval, the collar portion of the light guide supports the reflector, and the circuit board on which the light source is mounted via the reflector and the light guide are surely provided. Can be positioned and held.

Moreover, in the illuminating device according to claim 3, in the illuminating device according to claim 2, the illuminating device includes a holding member that sandwiches the reflector between the flange portion of the light guide and the circuit board. Thus, by holding the circuit board and the light guide in pressure contact with the reflector, the gap between the light source and the light guide, which is a cause of illumination spots, can be kept constant without variation.

Further, in the illumination device according to claim 4, in the illumination device according to claims 2 and 3, both of the circuit boards of the light guide have a common reference plane, and the light guide of the light guide The diffuse reflection surface is held at a first position positioned from the common reference surface, the circuit board is positioned from the common reference surface, and the light source faces the one end surface of the light guide. The light guide attachment reference position and the light guide attachment reference position from the common reference plane can be easily matched by holding the light guide and the circuit board through the reflector from the holding member. , Variation in the mounting position of the light source facing the end face of the light guide (position relative to the normal direction of the optical axis) can be minimized, and in addition to adjusting the predetermined gap between the light guide and the light source, it suppresses illumination spots Image reading device It is not the amount of light spots is generated in the image read is there to.

Moreover, in the illuminating device according to claim 5, in the illuminating device according to claim 4, the common reference plane is provided in a unit frame constituting the illuminating device, and the light guide is supported by the unit frame. The diffuse reflection surface of the light guide is held at a first position positioned from the common reference surface via the frame, and the light source attachment reference position and the light guide attachment By aligning the reference position with the unit frame as a common reference plane, it is excellent in device assembly without adjusting the light source mounting position (position relative to the optical axis normal direction) facing the end face of the light guide. ing.

Further, in the illumination device according to claim 6, in the illumination device according to claim 4, the common reference plane is provided on a unit frame constituting the illumination device, and the circuit board is positioned on the unit frame. A positioning part is formed, and the circuit board includes a positioning support part supported by the positioning part of the unit frame, so that the positioning support part of the circuit board is simply used as the positioning reference part of the light guide. By simply mounting, the mounting position of the light source facing the end face of the light guide (position with respect to the normal direction of the optical axis) can be adjusted without variation, and the assembly of the apparatus can be further improved.

Moreover, in the illuminating device according to claim 7, in the illuminating device according to claim 1, the light emission surface of the light guide is formed by a circumferential surface, and the diffuse reflection surface is a circumferential surface thereof. The light source mounted on the circuit board is disposed at a position for forming an optical axis normal that exits from the light exit surface through the center of the circle forming the The light source is disposed at a position displaced toward the light exit surface with respect to the center of the circle, and the light source is disposed between the center of the circle formed by the circumferential surface and the light exit surface. The amount of light at both ends of the body can be made higher than the amount of light at the center, and an optimal light amount distribution can be obtained for the illumination device mounted on the optical reduction system image reading device described above.

Moreover, in the illuminating device according to claim 8, in the illuminating device according to claim 1, the light exit surface of the light guide is formed by a circumferential surface, and the diffuse reflection surface is a circumferential surface thereof. The light source mounted on the circuit board is composed of two light sources, a first light source and a second light source, which are disposed at positions where an optical axis normal line exiting from the light exit surface passes through the center of the circle forming the light source. The first light source is disposed on the optical axis normal line of the diffuse reflection surface and at a first position displaced toward the light exit surface side with respect to the center of the circle, and the second light source By disposing at the second position displaced on the diffuse reflection surface side with respect to the center of the circle on the axis normal, the light quantity is increased almost twice, and the light quantity at both ends of the light guide is increased in the center. The light intensity distribution is optimal for lighting devices mounted on optical reduction system image readers. Not only optimal added document by bright illumination to the image reading apparatus of a so-called sheet-through mode equipped for reading while feeding automatically, can speed up the image reading speed.

Further, in the illumination device according to claim 9, in the illumination device according to claim 6, the first and second light sources are separated from each other by the reflector, and the light source is separated from one end surface thereof. By separating the light entering the light guide from each other, the spectral characteristics of the light sources of the first and second light sources are individually regulated, and the first and second light sources regulated to the optimum spectral characteristics. Can be incident on the end face of the light guide only from the region where the light is regulated by the reflector, and illumination spots can be further suppressed.

Furthermore, in the image reading apparatus according to the tenth aspect, the platen on which the read original is placed, the light source that illuminates the read original placed on the platen, and the read original illuminated by the light source. An image reading apparatus comprising: a light receiving unit that receives reflected light, wherein the light source includes the illumination device according to any one of claims 1 to 9 so that there is no illumination spot and the image is read. There will be no unevenness in the amount of light.

1 is a cross-sectional view showing an overall configuration of an image reading apparatus according to the present invention. FIG. 2 is a cross-sectional view illustrating a configuration of a reading carriage that reads a document image in the image reading apparatus of FIG. 1. FIG. 2 is a perspective view showing an external structure of a carriage in the image reading apparatus of FIG. 1. The perspective view which shows the external appearance structure which looked at the carriage of FIG. 3 from the downward direction. The top view which shows the external appearance structure which looked at the carriage of FIG. 3 from upper direction. The perspective view which shows the illuminating device mounted in the carriage of FIG. The partial exploded side view of the illuminating device of FIG. The partial exploded perspective view of the illuminating device of FIG. It is a principal part enlarged view in the illuminating device of FIG. 8, (a) is side surface fragmentary sectional view, (b) is the external view seen from the one end light source side of a light guide, (c) is from the other end side of a light guide. External view seen. The principal part enlarged view explaining the state of the reflected light in the light guide in the illuminating device of Fig.9 (a). The top view seen from the light guide body explaining the light source unit in the illuminating device of FIG. FIG. 12 is an enlarged cross-sectional view of the light source unit of FIG. 11. The disassembled perspective view of the light source unit of FIG. It is a figure which shows the structure of the light source and light source board | substrate of the light source unit of FIG. 13, (a) is a top view which shows the light source feed circuit pattern wiring of a light source board | substrate, (b) is sectional drawing of the ZZ surface, (c). FIG. 3 is a plan view showing a terminal pattern of a light source. 11A and 11B are views for explaining the positional relationship between the light source and the light guide in the light source unit of FIG. 11, wherein FIG. 11A is a side view, and FIG. 11B is a position of the light source with respect to the light guide viewed from one light source side of the light guide. (C) is a top view which shows the position of the light source seen from the other end side of the light guide. The plane enlarged view which shows the position of the light source with respect to the light guide of FIG.15 (b). It is a figure for demonstrating the positional relationship of the light source and light guide in the light source unit regarding the other Example corresponding to FIG. 15, (a) is a side view, (b) was seen from the one end light source side of the light guide. The top view which shows the position of the light source with respect to a light guide, (c) is a top view which shows the position of the light source seen from the other end side of the light guide. FIG. 6 is a spectral characteristic diagram showing spectral characteristics of the illumination device in the image reading apparatus of the present invention. 1 is a functional block diagram showing a control system for reading a document image in the image reading apparatus of FIG.

In the following, one embodiment of an image reading apparatus equipped with the illumination device according to the present invention will be described based on FIGS. 1 to 16, another embodiment of the image reading apparatus based on FIG. 17, and the image of the present invention based on FIG. The spectral characteristics of the illumination device in the reading device will be described with reference to FIG. 19 for an image data processing unit that reads a document image of the image reading device.

[One Example of Image Reading Apparatus]
First, an embodiment of an image reading apparatus equipped with an illumination device according to the present invention will be described with reference to FIGS. FIG. 1 shows the overall configuration of the image reading device, FIGS. 2 to 5 show the configuration of a reading carriage mounted on the image reading device, and FIGS. 6 to 10 show the illumination device serving as the light source of the reading carriage. 11 to 16 are for explaining the configuration of the light source unit of the illumination device.

<Overall configuration of image reading device>
FIG. 1 is a cross-sectional view showing the overall configuration of the image reading apparatus. This image reading apparatus is composed of the following image reading unit A and a document feeding unit B mounted thereon.

(Image reading unit A)
The image reading unit A includes a first platen 2 and a second platen 3 in the apparatus housing 1. The first platen 2 and the second platen 3 are made of a transparent material such as glass and are fixed to the top of the apparatus housing 1. The first platen 2 is formed with the maximum size of a usable document that can be manually placed, and the second platen 3 is formed with the maximum width of the usable document so as to read a document that moves at a predetermined speed. Yes. The first platen 2 and the second platen 3 are arranged side by side, guided below by the guide shaft 12 and the rail member GL, and supported in the apparatus housing 1 so as to be movable parallel to the platen surface. A reading carriage 6 reciprocated by Mc is incorporated.

(Original Feed Unit B)
The document feeding unit B is disposed above the first platen 2 and the second platen 3 so as to cover the first platen 2 and the second platen 3, and a lead roller (document feeding means) 21 and a carry-out roller 22 that feed the document sheet to the second platen 3. And. Further, on the upstream side of the read roller 21, a paper feed stacker 23 for stacking and storing original sheets, a paper feed roller 24 for separating and feeding the sheets stacked on the paper feed stacker 23 one by one, and separation feeding A registration roller pair 25 for correcting the skew of the leading edge of the sheet is disposed. Further, a lead sensor S 1 for detecting the leading edge of the original reaching the second platen 3 is provided in the paper supply path 26 for guiding the original sheet from the paper supply stacker 23 to the second platen 3, and the upper surface of the second platen 3. The backup roller 27 is arranged at the same peripheral speed as the lead roller 21, fits the original sheet on the second platen 3, and conveys it to the carry-out roller 22 arranged downstream of the platen. Further, on the downstream side of the carry-out roller 22, a paper discharge stacker 29 arranged in a vertically parallel manner is disposed below the paper discharge roller 28 and the paper feed stacker 23, and the first platen 2 is disposed at the bottom of the paper discharge stacker 29. There is provided a platen cover 5 for pressing and supporting a document sheet placed thereon.

Instead of the backup roller 27, a backup guide may be arranged above the platen. In the image reading apparatus described as the first embodiment described above, the first platen 2 and the second platen 3 are arranged side by side, and the document feeding unit B is mounted thereon. An image reading apparatus in which the two platen 3 is removed and only the first platen 2 is provided, an opening / closing cover is attached instead of the document feeding unit B, and the opening / closing cover covers the first platen 2 may be used.

(Original Fixed Reading Mode = Flat Bed Mode)
The document feeding unit B configured as described above is set on the first platen 2 by the operator selecting the document fixed reading mode, so-called flatbed mode, on the apparatus panel of the image reading unit A or on the screen of the PC. When the original sheet is read, the original sheet is placed on the apparatus housing 1 of the image reading unit A so as to be freely opened and closed, the original feeding unit B is lifted upward, and the first platen 2 is opened. The document sheet is covered with the platen cover 5 of the document feeding unit B, and the reading carriage 6 moves along the guide shaft 12 below the document sheet to perform a reading operation.

(Original scanning mode = sheet-through mode)
Also, the document feeder unit B has a second platen that is transported by the document feeder unit B when the operator selects a document flow scanning mode, so-called sheet-through mode, on the apparatus panel of the image reading unit A or on the screen of the PC. When reading a document sheet flowing over 3, the reading carriage 6 is moved to the reading position of the second platen 3 by the above-described travel driving means 19 and carriage motor Mc and stopped, and is read. I do.

<Configuration of reading carriage>
Next, the reading carriage 6 will be described. 2 is a cross-sectional view showing a configuration of a reading carriage 6 that reads an original image in the image reading unit A of FIG. 1, FIG. 3 is a perspective view showing an external structure of the reading carriage 6, and FIG. 4 shows the reading carriage 6 of FIG. FIG. 5 is a plan view showing the external structure of the reading carriage 6 shown in FIG. 3 as viewed from above.

First, the reading carriage 6 will be described with reference to FIG. The reading carriage 6 includes a unit frame 11 made of a heat-resistant resin and a metal plate, a light source unit 9 (illuminating device) including a pair of a first light source body 9a and a second light source unit 9b, and a light source unit 9 A reflecting mirror 10 composed of first to sixth mirrors 10a to 10f for deflecting reflected light from the original sheet illuminated by the light, and condensing the reflected light from the original sheet reflected by the reflecting mirror 10. A lens 7 and a line sensor 8 (imaging device) disposed in an image forming unit that forms an image with the condenser lens 7 are mounted. The image data output as an electrical signal from the line sensor 8 is electrically connected to an image processing unit (data processing board) to be described later by a data transfer cable (not shown) so as to be transferred to the image processing unit.

As shown in FIGS. 2 and 3, the unit frame 11 has a reading opening 34 corresponding to the reading line width W of the original sheet. The reading opening 34 reads the original sheet irradiated with light from the light source unit 9. The line sensor 8 can receive the reflected light reflected from the surface. The unit frame 11 is movably supported by the guide shaft 12 and the rail member GL so as to reciprocate with a predetermined stroke.

The light source unit 9 will be described in detail as a lighting device, which will be described later. The light source unit 9 is composed of a light source that irradiates linear light along the reading opening 34 of the unit frame 11, and is integrally attached to the unit frame 11. Then, the reading light is applied to a document sheet on a platen described later.

The reflection mirror 10 is appropriately composed of a plurality of sheets so as to form a predetermined optical path length, and in the case of this embodiment, it is composed of six sheets. Reflected light from the image reflected on the original surface of the original sheet by the first mirror 10a is reflected toward the second mirror 10b, and the reflected light is reflected by the second mirror 10b and reflected toward the third mirror 10c. The reflected light is reflected by the third mirror 10c and again reflected toward the second mirror 10b, the reflected light is reflected toward the fourth mirror 10d, and the reflected light is reflected by the fourth mirror 10d, and the reflected light is reflected. The light is reflected toward the fifth mirror 10e. Finally, the reflected light reflected by the fifth mirror 10e is guided to the sixth mirror 10f, and the reflected light reflected by the sixth mirror 10f is converted into the condenser lens 7. To guide. The reflected light of the document image is not limited to such an optical path formation, and it is possible to form an optical path using, for example, first and second reflection mirrors.

The condensing lens 7 is composed of one or a plurality of imaging lenses, and forms an image on the line sensor 8 of the reflected light reflected from the original surface of the original sheet transmitted through the reflecting mirror 10.

The line sensor 8 is composed of a photoelectric conversion sensor such as a CCD, and receives and photoelectrically converts the reflected light of the document image sent from the condenser lens 7. The line sensor 8 is composed of a color line sensor, and sensor elements constituting R (Red), G (Green), and B (Blue) pixels are arranged in three lines in a line. The line sensor 8 having such a configuration is attached to the sensor circuit board 45, and the sensor circuit board 45 is fixed to the unit frame 11.

<Reading carriage support mechanism>
As shown in FIGS. 3 to 5, the reading carriage 6 has one end pivotally supported by the guide shaft 12 by a bearing disposed in the apparatus housing 1, and the other end of the reading carriage 6 is slidable on the rail member GL. The device housing 1 is supported so as to be reciprocally movable. The carriage support mechanism composed of the guide shaft 12 and the rail member GL is attached to the apparatus housing 1 in parallel with each other and to both the first platen 2 and the second platen 3 in parallel. The platen 2 and the second platen 3 are opposed to the plane and are configured to reciprocate stably in parallel.

<Scanning carriage movement mechanism>
The carriage movement mechanism of the reading carriage 6 includes a carriage motor Mc composed of a drive motor such as the pulse motor and the DC motor with an encoder shown in FIG. 1, a wire that rotates by the reciprocating rotation of the carriage motor Mc, a timing belt, and the like. The pulling member 17 and a pair of pulleys 46a and 46b rotatably supported by the apparatus frame 1 are configured. A carriage motor Mc that can be rotated forward and backward is connected to the one pulley 46b, a traction member 17 is stretched between the pair of pulleys 46a and 46b, and the reading carriage 6 is connected to the traction member 17 to move the carriage. The mechanism is configured.

<Reading operation of reading carriage>
The reading carriage 6 connected to the carriage moving mechanism uses a shading plate as a light source for adjusting a light amount characteristic (not shown) disposed above the home position HP, that is, a position corresponding to the home position HP shown in FIG. Depending on the mode selected from the home position HP, the unit 9 is stopped at the position where the light is illuminated. In the document flow reading mode, the reading carriage 6 is shown at the position indicated by the solid line in FIG. Is moved to the position of the reading carriage 6 indicated by the two-dot chain line.

<Configuration of lighting device>
Next, an illumination device that is attached to the above-described reading carriage 6 and used as the light source unit 9 will be described with reference to FIGS. 6 is a perspective view showing the lighting device mounted on the carriage of FIG. 3, FIG. 7 is a partially exploded side view of the lighting device of FIG. 6, FIG. 8 is a partially exploded perspective view of the lighting device of FIG. FIG. 9 is an enlarged view of a main part of the illumination device of FIG. 8, (a) is a side sectional view, (b) is an external view as viewed from one light source side of the light guide, and (c) is the other end side of the light guide. FIG. 10 is a main part enlarged view for explaining the state of reflected light in the light guide in the illumination device of FIG. 9A.

The light source unit 9 that is this illumination device irradiates linear light along a reading line that forms a reading width in the main scanning direction orthogonal to the reading surface R shown in FIG. The light source unit 9 is composed of a first light source body 9a and a second light source unit 9b shown in FIG. 2, and each of the first light source body 9a and the second light source unit 9b is a unit frame 11 of the carriage 6 shown in FIG. Are accommodated in a first accommodating portion 13a and a second accommodating portion 13b formed in a light source accommodating portion (light guide support frame) 13 supported by the first and second accommodating portions. As shown in FIG. 7, the first light source body 9a and the second light source unit 9b are respectively composed of a light source unit La and a light guide body 30 that support the light emitting body 40. Hereinafter, the configuration and guide of the light source unit La will be described. The configuration of the light body 30 will be described in detail.

<Configuration of light source unit>
First, the configuration of the light source unit La will be described in detail with reference to FIGS. 8 and 11 to 14. 11 is a plan view of the light source unit La in the illumination device of FIG. 8 as viewed from the light guide side, FIG. 12 is an enlarged sectional view of the light source unit La of FIG. 11, and FIG. 13 is an exploded perspective view of the light source unit La of FIG. FIGS. 14 and 14 are views showing the structure of a light source substrate to which the light emitter 40 of the light source unit La in FIG. 13 is electrically attached. FIG. 14 (a) is a plan view showing light source power supply circuit pattern wiring of the light source substrate. Sectional drawing of the ZZ surface, (c) is a top view which shows the terminal pattern of a light source.

As shown in FIG. 8, the light source unit La is composed of a heat radiating member 14, a heat conductive sheet 15, and a circuit board 16, and the circuit board 16 includes a first light emitter as shown in FIG. A lens cap 43 is attached to each of the (white LED) 41 and the second light emitter (white LED) 42, and a reflector 49 is put on the lens cap 43. In addition, an insulating mylar 47 that insulates portions other than those covered by the reflector 49 is provided. In the following, description of individual parts and unit assembly will be described.

* Description of Light Emitter First, the light emitter 40 will be described with reference to FIGS. The light emitter 40 includes two light emitting elements, a first light emitter 41 and a second light emitter 42, and is mounted on the circuit board 16. In this embodiment, the light emitting element is composed of a white LED chip. Further, as shown in FIG. 14C, the luminous body 40 forms an anode 40a and a cathode 40b for supplying power, and a thermal pad 40c for heat dissipation.

* Description of Circuit Board The circuit board 16 on which the light emitting body 40 is mounted is fixed to the heat radiating member 14 via the heat conductive sheet 15 as shown in FIG. 14B, and the light emitting body 40 is mounted on the circuit board 16. Has been. As shown in FIG. 14 (a), the circuit board 16 has a wiring pattern 16a-1 made of a material having high conductivity such as copper, silver, gold, etc. for emitting and energizing the light emitter 40 on the surface of the circuit board. 16a-5 are formed, and the back surface of the substrate is covered with a heat conductive layer 16b-2 having a particularly high thermal conductivity such as copper, silver, and aluminum, and a part of the heat conductive layer is formed on the light emitting body 40. The protrusion 16b-1 is formed on the substrate surface so as to be in direct contact with the light emitting source. The circuit board 16 has a particularly high thermal conductivity such as copper, silver or aluminum on the back surface of the circuit board 16 in a state where a through hole for forming the protrusion 16b-1 is previously formed in an insulating board made of an epoxy material. After forming the heat conductive layer 16b-2 and the protrusion 16b-1 by injection molding of the heat conductive material, a layer made of a material having high conductivity such as copper, silver, gold or the like is formed on the substrate surface. Is formed by etching so as to leave the wiring patterns 16a-1 to 16a-5 and the protrusions 16b-1. The circuit board 16 has the light emitter 40 mounted thereon, and the thermal pad 40c of the light emitter 40 and the protruding portion 16b-1 protruding from the back surface of the substrate are in pressure contact with each other, so that the heat generated when the light emitter 40 is turned on. Is radiated to the heat conductive layer 16b-2 on the back surface of the substrate through the protrusion 16b-1 in contact with the thermal pad 40c.

The circuit board 16 may be formed in multiple layers. In this case, it is desirable that the heat conductive layer 16b-2 on the back surface of the circuit board and the projecting part 16b-1 projecting on the surface of the board be connected so as to maintain high heat conduction. Moreover, you may comprise so that the heat | fever of the light-emitting body 40 may be conducted to the thermal radiation member 14 through the anode 40a and the cathode 40b.

* About the heat conductive sheet The heat conductive sheet 15 is an elastic sheet material made of an insulating synthetic resin having high thermal conductivity made of, for example, a thermoplastic elastomer or a non-silicone thermoplastic resin, and having high elasticity. As shown by the dotted line in FIG. 14B, the heat of the light emitting body 40 interposed between the circuit board 16 and the heat radiating member 14 to be described later and radiated to the heat conductive layer 16b-2 of the circuit board 16 is dissipated. Is provided for efficient conduction.

* Regarding the heat radiating member The heat radiating member 14 is made of a metal material having a high thermal conductivity such as an aluminum alloy. In order to increase the surface area, for example, a plurality of protruding plate-like fins are formed as shown in FIG. The heat of the luminous body 40 conducted through the above-described heat conductive sheet 15 is efficiently radiated.

* Insulation Mylar As shown in FIG. 8, an insulation mylar 47 is provided on the surface of the circuit board 16 on the light guide 30 side. The insulating mylar 47 insulates the circuit board 16 from contact with the metal members constituting the carriage 6 and protects the surface of the circuit board 16 from damage to the substrate surface.

* Further, as shown in FIGS. 8 to 13, in order to make the light from the illuminant 40 enter the light guide 30 without loss, the reflectors of the first illuminant 41 and the second illuminant 42 are used. A reflector 49 that restricts the characteristics within 90 ° is provided. One reflector 49 is provided for each light emitter. The reflector 49 is made of a material having a high reflectivity obtained by evaporating a metal such as aluminum on a plastic material, and has an umbrella shape extending from the light emitting body 40 toward the light guide body 30. At this time, the umbrella-shaped portion may be formed with a curved surface or a flat surface.

* Similarly to the holding member, the holding member 48 shown in FIG. 8 presses and urges the heat radiating member 14 and the flange 30N provided at the one end 30L of the light guide 30 through the reflector 49 as shown in FIG. In addition, the gap between the light guide 30 and the light emitter 40 is regulated to be constant. Accordingly, the holding member 48 is formed of a spring member having rigidity such as a metal having a spring property, and pulls the light guide 30 toward the heat radiating member 14 and pulls the heat radiating member 14 toward the light guide 30. .

[Configuration of light guide]
Next, the light guide will be described based on FIGS. 9 and 10 described above and FIGS. 15 and 16 newly. FIGS. 15A and 15B are diagrams for explaining the positional relationship between the light source and the light guide in the light source unit of FIG. 11, where FIG. 15A is a side view and FIG. 15B is a light guide viewed from one light source side of the light guide. The top view which shows the position of the light source with respect to a body, (c) is a top view which shows the position of the light source seen from the other end side of a light guide, FIG. 16 shows the position of the light source with respect to the light guide of FIG.15 (b). It is a plane enlarged view.

The light guide 30 is a rod-like light-transmitting member having a length corresponding to the reading width (reading line width) W as shown in FIGS. 9 and 10, and is rich in light-transmitting properties such as transparent acrylic resin and epoxy resin. It is made up of materials. As shown in FIGS. 15 and 16, the cross-sectional shape is formed so that the light scattering surface 32 and the light emitting surface 33 face each other, the light emitter 40 is disposed on one end surface 30L, and the other end surface 30R is disposed on the other end surface 30R. A reflective plate 50 having a mirror-finished surface and a reflective layer having a high reflectivity such as aluminum or silver is attached by an adhesive (double-sided tape) 60 having a light transmittance of 90% or more so as to form a reflective surface. ing. Further, as shown in FIG. 9, the light scattering surface 32 and the light emitting surface 33 are arranged to face each other with a length of the reading line width W substantially in parallel with a distance Ld.

<Description of light scattering surface>
The light scattering surface 32 is surface-processed so as to diffusely reflect the light that is formed on the uneven surface by coating, etching, or molding with a reflective paint such as urethane-based white ink. The surface processing is not performed on the side close to the one end face 30L of the light guide 30 as shown in FIGS. 9 and 10, and from the place where a certain distance has passed from the one end face 30L to the other end face 30R. Further, the base end portion on the one end surface 30L side is longer than the base end portion of the reading line width W on the one end surface 30L side as shown in FIG. This is because when the reading line width W and the surface processed portion have substantially the same length, the peak of the light amount on the 30L side of the reading line width W is shifted to the 30R side, and the light amount at the end on the 30L side is insufficient. For this reason, the light amount distribution is set long in advance so as to be an appropriate value.

Further, the light emitting surface 33 of the light guide 30 is formed as a circumferential surface as shown in FIG. The circumferential surface is formed with a radius of 3.7 mm ± 0.1 mm, and the center P1 of the circumferential surface is provided on a normal line hx that is the center of the illumination optical path. The light scattering surface 32 is located outside the circumferential region, and the position is set at a position of 8.46 mm ± 0.1 mm from the light emitting surface 33 on the normal hx.

<Description of reflector>
The reflective plate 50 and the adhesive material 60 are formed as a single sheet-like material, and the adhesive material 60 is made of an acrylic sheet-like material having a light transmittance of 90% or more. A reflection plate 50 serving as a sheet base material having the above-described reflection surface formed on the front surface side and a sheet material in which a release sheet provided with a release surface (not shown) on the back surface side are stacked. In the present embodiment, the thickness of the reflection plate and the sheet material of the adhesive material is 25 micrometers. However, if the light transmittance can be ensured to be 90% or more, the thickness can be 25 micrometers or more. Then, the release sheet is peeled off from the adhesive material 60 from the sheet material that has been punched in conformity with the outer shape of the other end surface 30R of the light guide, and the reflection plate 50 to which the adhesive material 60 is attached is attached to the other end surface of the light guide. By attaching to 30R, the reflector attaching operation can be easily performed with good workability. Moreover, the adhesive material 60 is reliably provided between the reflector 50 and the other end surface 30R of the light guide by simply attaching the reflective plate 50 to which the adhesive material 60 is attached in advance to the other end surface 30R of the light guide. A constant gap can be provided on one end face of the light guide at a predetermined interval with the thickness of the material, and the reflector 50 is in a state close to the light environment of the light source. Thus, by creating a pseudo light source that is more similar to the light source, it is possible to obtain bright and uniform left and right spectral characteristics as linear light as in the case where the light sources are provided on both end faces of the light guide.

Further, as shown in FIG. 9, the reflection surface of the other end surface 30 </ b> R can correct the above light quantity characteristic by adjusting the angle by an angle θ in the length direction with respect to the normal direction hx of the light scattering surface 32. It becomes. That is, as shown in FIG. 9, when the angle of the reflecting surface is tilted by plus θ in the clockwise direction, the amount of light at both ends of the main scanning direction increases. Conversely, when tilted by minus θ in the counterclockwise direction, the amount of light at both ends of the main scanning direction becomes By reducing this angle and setting this angle when designing the light guide 30 in advance, it becomes possible to easily match the characteristics of the condenser lens 7. The optimum value is about 5 °. Note that the reflecting surface of the other end surface 30R is also inclined with respect to the light guide side surface 30S in order to improve convenience when the light guide 30 is removed from the mold.

Further, the light guide 30 has a protrusion 30P as shown in FIG. The protrusion 30P is a bowl-shaped protrusion protruding from the cross section as shown in the figure. The protruding portion 30P is not provided in the vicinity of the one end portion 30L, and is located between the base end portion where the surface processing of the light scattering surface 32 is performed and the base end portion of the reading line width W. And provided between the other end 30R. This is to prevent the projection 30P from extending to the one end face 30L and causing the light to be irregularly reflected by the projection 30P and affecting the spectral characteristics, and to prevent the amount of reflected light from attenuating outside that portion. is there.

Therefore, the light of the light emitting body 40 introduced into the light guide 30 is diffused in a predetermined direction by the light scattering surface 32, and the light introduced into the light emitting surface 33 is reflected inside when the angle exceeds a predetermined critical angle, When it is below the critical angle, it is emitted to the outside. The light indicated by the arrow ha in FIG. 8 is reflected in the light guide 30 and dispersed in the reading line width W direction, and the light indicated by the arrow hb is emitted from the light emitting surface 33 to the reading surface R. Although not shown, light is incident in a spherical direction (360-degree direction; the illustrated one is a 60-degree wide-angle direction) from a light emitter 40, which will be described later, and irradiates the light scattering surface 32 and the light emitting surface 33.

In addition, light that has repeatedly reflected in the light guide 30 and reaches the other end surface 30R is reflected by the surface of the other end surface 30R, returned to the light emitter 40 side, and similarly reflected by the light scattering surface 32 and indicated by an arrow ha. Is emitted from the light emitting surface 33 to the reading surface R. Using this characteristic, the arrangement of the light emitter 40 with respect to the one end surface 30L is adjusted, the light emitted from the light emitting surface 33 on the one end surface 30L side to the reading surface R is lowered, and the light reflected on the surface of the other end surface 30R is reflected. By increasing the light amount on the one end surface 30L side, the light amount on the other end surface 30R side can be increased, the light amount emitted to the reading surface R is made uniform, and when using the optical reduction system type condensing lens 7 It is possible to adjust the light amount close to the light amount distribution of the cosine fourth law that depends on the lens characteristics.

<Arrangement of light emitter and light guide>
Next, the positional relationship between the light emitter 40 and the light guide 30 will be described with reference to FIGS. 13 and 16. The first light emitter 41 and the second light emitter 42 constituting each light emitter 40 shown in FIG. 13 are located at the position P1 on the normal line (outgoing light path direction) hx of the light scattering surface 32 described above with reference to FIG. The first light emitters 41 and the second light emitters 42 are arranged at the position P2. The first light emitter 41 is disposed at a distance Ld1 from the light scattering surface 32, and the second light emitter 42 is disposed at a distance Ld2. An offset amount dx is formed between the light emitters 41 and 42. In the present embodiment, the first light emitter 41 disposed at a position close to the light scattering surface 32 and the second light emitter 42 disposed at a position close to the light exit surface 33 are each composed of two light emitting elements. In order to further diffuse light, a lens 43 is provided between the light emitting element and the light guide 30. The first light emitter 41 and the second light emitter 42 are disposed on the normal line hx. In other words, the first light emitter 41 is arranged at a distance Ld1 and the second light emitter 42 is arranged at a distance Ld2 (Ld1 <Ld2) with respect to the light scattering surface 32.

<Gap between light emitter and light guide>
The circuit board 16 on which the light emitting element is mounted is disposed with a gap d between the light emitting surface and the one end surface 30L of the light guide 30. The gap d is preferably in the range of 0.1 millimeters to 0.55 millimeters. FIG. 9 shows an arrangement structure in a state where the light emitters 40 (41, 42) are mounted on the circuit board 16. The light emitter 40 (41, 42) is composed of a planar light emitting element, and is composed of a white LED. Furthermore, in order to increase the total amount of light, a similar light emitter 40 (41, 42) may be disposed instead of the reflective paint on the other end surface 30R. Further, in this case, the first light emitter 41 and the second light emitter 42 enter light from one end face 30 </ b> L of the light guide 30 from different positions between the light scattering surface 32 and the light emitting surface 33. At the same time, the first light emitter 41 and the second light emitter 42 are arranged at a distance from each other in the direction of the outgoing light path from the light emitting surface 33 toward the reading surface R (indicated by an arrow hx in FIG. 5).

<Assembly of light source unit>
Next, assembly of the light source unit will be described with reference to FIG. First, the light emitting body 40 (41, 42) is mounted on the circuit board 16, and the lens cap 43 is mounted. The circuit board 16 is integrally attached by screwing in a state where the circuit board 16 is in close contact with the heat radiating member 14 (heat sink) via the heat resistant sheet 15 (heat resistant resin plate). Then, the heat dissipation member 14 (heat sink) to which the circuit board 16 is attached and the light guide 30 are held by the holding member 48 via the reflector 49, and the circuit board 16 is pressed into contact with one surface of the reflector 49. The light guide 30 is attached to the unit frame 11 of the carriage 6 in a state where the light guide 30 is pressed against the surface of the carriage 6.

[Other Embodiments of Image Reading Apparatus]
Next, another embodiment of the above-described lighting device will be described. FIGS. 17A and 17B are views for explaining the positional relationship between the light source and the light guide in a light source unit according to another embodiment corresponding to FIG. 15, where FIG. 17A is a side view, and FIG. The top view which shows the position of the light source with respect to the light guide seen from the side, (c) is a top view which shows the position of the light source seen from the other end side of the light guide. The difference from the light source unit shown in FIG. 15 is that the arrangement and brightness of the light source and the light guide are different depending on whether the light emitting source 40 is composed of one light emitting element or two light emitting elements. However, the basic functions are almost the same.

In this embodiment, as shown in FIG. 17A, in this embodiment, a light emitting source 40 composed of one light emitting element facing a certain gap is arranged on one end face 30L of the light guide 30. The light source 40 is disposed at the light source position P2 shown in FIG. 16 described above. The spectral characteristics at that time will be described later with reference to FIG. As in FIG. 15, only one light source unit that is received in a pair in the front and rear direction in the sub-scanning direction with respect to the center of the reading surface R is displayed as shown in FIG.

Next, the spectral characteristics of the illumination device in the image reading apparatus of the present invention will be described based on the spectral characteristics diagram of FIG. In the figure, the spectral characteristics indicated by P1 to P4 indicate the spectral characteristics obtained when the light source 40 is disposed at the positions P1 to P3 shown in FIG. First, the spectral characteristic indicated by P1 indicates the spectral characteristic obtained when the light emitting source 40 composed of one light emitting element (white LED) is arranged at the position P1 shown in FIG. 16, and the spectral characteristic indicated by P2 is FIG. 16 shows the spectral characteristics of the other embodiment shown in FIG. 17 obtained when the light emission source 40 is arranged at the position P2 shown in FIG. 16, and the spectral characteristics shown by P3 show the light emission source 40 in FIG. The spectral characteristic obtained when it arrange | positions in the position of P3 shown by is shown. The spectral characteristic indicated by P4 is obtained when the light source 40 (41, 42) composed of two light emitting elements (white LEDs) is arranged at the positions P2 and P3 shown in FIG. The spectral characteristics of the first embodiment shown in FIGS. 2 to 15 are shown. Looking at this spectral characteristic, since the illumination device of the image reading apparatus having the contact optical system described above requires a substantially uniform spectral characteristic, a light emitting source composed of one light emitting element. By arranging 40 at a position P1 shown in FIG. 16, an illumination device having ideal spectral characteristics can be obtained. On the other hand, in the case of an illumination device of an optical reduction system image reading device that is affected by the cosine fourth law by a condensing lens, the light amount distribution needs to be higher at both end portions than at the central portion. In the case where reading is possible even when the total amount of light is relatively low, an illuminating device having ideal spectral characteristics can be obtained by arranging a light emitting source 40 composed of one light emitting element at a position P2 shown in FIG. If the light source 40 (41, 42) composed of two light emitting elements cannot be read unless the total light quantity is relatively high, the light source 40 (41, 42) composed of two light emitting elements is placed at the position P2 shown in FIG. An illuminating device having ideal spectral characteristics can be obtained by disposing the two light emitting sources 42 and disposing the first light emitting source 41 at the position P3.

[Configuration of image reading control system]
Next, an outline of a control system for reading a document image in the image reading apparatus shown in FIG. 1 will be described based on FIG. FIG. 19 is a functional block diagram showing a control system for reading a document image in the image reading apparatus. In FIG. 19, a portion surrounded by a two-dot chain line corresponds to the reading carriage 6 and is surrounded by a thin line. The portion corresponds to the control board S provided in the image reading unit A. The operation of the image reading apparatus by each basic functional block is as follows. The control unit CPU of the control board S drives the motor driving means S-MC, the light source lighting means S-La, and the sensor driving means S-CCD. Then, the sensor driving means S-CCD causes the line sensor 8 to read the original sheet. That is, with the reading carriage 6 moved or stopped as necessary by the motor driving means S-MC, the original sheet is illuminated while the light source 40 is appropriately turned on by the light source lighting means S-La, and the reflected light from the original is reflected. An image is formed on the line sensor 8 and photoelectrically converted to accumulate charges. The output signal from the sensor 16 is amplified by the amplifier circuit AMP and then converted into a digital image signal by the A / D converter. The image signal digitized by the A / D converter is subjected to image processing such as shading correction, digital gain adjustment, and digital black correction using shading data stored in the RAM in the image processing means. Thereafter, the digital image signal is stored in a line buffer and transferred to an external device such as a personal computer PC via an interface. These are all performed by the control unit PC controlling each functional block based on an instruction from the driver means of the external device.

[Light source control configuration]
The control of the light source unit 9 by the light source lighting means S-La will be described. As shown in FIG. 9, the first light source body 9a and the second light source unit 9b irradiate light onto the reading surfaces R of the first platen 2 and the second platen 3, and use diffusely reflected light reflected from the read original. Yes. The light source unit 9a (9b) is not necessarily composed of two light sources as shown in the figure, and may be composed of one or three or more light sources. In this case, in the document feeding unit B described later, the speed of the document traveling on the second platen 3 is set higher than the speed at which the carriage 6 moves along the first platen 2.

That is, the reading speed of the second platen 3 is higher than the reading speed of the first platen 2. For this reason, it is preferable that the second platen 3 is higher than the first platen 2 in the amount of light applied to the document.

Accordingly, when the carriage 6 is positioned on the first platen 2, the first light guide 30a is turned on, and when the carriage 6 is positioned on the second platen 3, the first light guide 30a and the second light guide 30b are turned on.

[Additional explanation of new matter]
The supplementary explanation will be given again for the new matter of the illumination device according to the present invention described as the illumination device of the image reading apparatus.

<Gap retention between light guide and light source by reflector>
First, it supplements about the gap maintenance of a light guide and a light source. As shown in FIG. 9A, an end face (30a, 30b) that captures light, a diffuse reflection surface (32) that diffusely reflects light captured from the end faces (30a, 30b), and a diffuse reflection surface (32). A light guide (30) having a light exit surface (33) for emitting diffusely reflected light toward an irradiation surface (R: see FIG. 2), and at least one end surface (30a, 30) of the light guide (30) In a lighting device (9) comprising a light source (40) facing 30b), a reflecting surface (9a, 30b) that reflects light from the light source (40) toward one end face (30a, 30b) of the light guide (30). 9b), the light guide (30) has a flange (30N) that abuts the reflector (49) on one end face (30a, 30b) of the light guide (30), and the light source (40) Mounted on the circuit board (16) on which the light source is mounted, the reflector (4 ) Is sandwiched between the collar (30N) of the light guide (30) and the circuit board (16), and is held at a predetermined interval between the light source (40) and the light guide (30), so that the light source is reflected by the reflector. The gap between the light source and the light guide can be defined, the predetermined gap between the light source and the light guide is not changed, and illumination unevenness can be suppressed. By using this illumination device as a light source unit of the image reading device, no unevenness in the amount of light occurs in the read image.

The light guide (30) has a flange (30N) that abuts the reflector (49) on one end face (30a, 30b), and the light source (40) is mounted and attached to the circuit board (16). The reflector (49) is sandwiched between the collar (30N) of the light guide (30) and the circuit board (16), and is held at a predetermined interval between the light source (40) and the light guide (30). The collar portion of the light guide supports the plane of the reflector over a wide range, and the circuit board on which the light source is mounted and the light guide can be reliably positioned and held via the reflector.

Moreover, the holding member (48) which clamps a reflector (49) with the collar part (30N) of a light guide (30), and a circuit board (16) is provided. As described above, the holding member (48) includes a heat radiating member (14) for screwing the circuit board (16) on which the light source (40) is mounted to the unit frame (11) via the heat resistant sheet (15). The gap (30N) between the light guide (30) housed in the frame (13) that forms the light source housing that houses the light guide (30) supported by the unit frame (11). Hold it. Then, the holding member (48) holds the circuit board (16) and the light guide (30) in pressure contact with the reflector (49), so that the light source (40) and the light guide (30), which are the cause of the illumination spots. And the gap can be kept constant without variation.

In the embodiment in which the gap between the light source and the light guide is defined by the reflector, the plane of the circuit board on which the light source is mounted is arranged on one of the left and right planes of the reflector, and the plane composed of one end surface of the light guide is formed on the other side. The structures are in direct contact with each other, but the following structures may be used.

One of the structures is a structure in which a thin insulating mylar is sandwiched between the reflector and the circuit board on which the light source is mounted, because the reflector surface is coated with a metal film having good reflection efficiency such as aluminum or silver. A structure in which a thin light-shielding mylar is sandwiched in order to suppress variation in light of the light source narrowed down by the reflector may be used.

Moreover, although each surface contact | abutted with a reflector is formed in the plane, it does not need to be a plane. For example, when one of the abutting surfaces has an uneven shape, the other may have an inverted uneven shape. Further, when one of the abutting surfaces has a curved surface shape, the other may have an inverted curved surface shape.

Further, when the light irradiation surface of the light source mounted on the circuit board is wide and flat, the light source itself may be in contact with the reflector.

Moreover, even if it is the structure which formed the reflector itself integrally as a part of a light source or a light guide, the gap of a light source and a light guide may be prescribed | regulated by the reflector of this invention.

Furthermore, in the above-described embodiment, a light source is arranged at one end of the light guide, and a reflector serving as a pseudo light source is arranged at the other end, but the same is applied to the other end of the light guide to increase the absolute light quantity. When the light source is disposed in the structure, the reflector is naturally disposed on the other surface of the light guide.

<Positioning of the light source facing the light guide>
Next, it supplements about positioning of the light source which opposes a light guide. As shown in FIG. 10, both the light guide (30) and the circuit board (16) have one common reference surface (11s), and the diffuse reflection surface (32) of the light guide (30) is the common reference surface. The circuit board (16) is positioned from the common reference plane (11s), and the light source (40) is one of the light guides (30), held at the first position (d3) positioned from the surface (11s). The positioning structure is arranged at the second position (d2) facing the end faces (30a, 30b). That is, the diffused reflection surface (32) of the light guide (30) is positioned from the common reference surface (11s) to the first position (d3), so that the light guide is attached from the common reference surface (11s). A reference position (d4) is determined. At the same time, the light source (40) mounted on the circuit board (16) is mounted on the light guide (30) by attaching the circuit board (16) on which the light source (40) is mounted to a predetermined position on the common reference plane (11s). The light source mounting reference position (d2) and the light guide mounting reference position (d4) from the common reference plane (11s) are arranged at the second position (d2) facing the one end face (30a, 30b). It can be easily matched, and variation in the light source mounting position (position relative to the normal direction of the optical axis) facing the end face of the light guide can be minimized, and a predetermined gap between the light guide and the light source In addition to the adjustment of lighting, it can suppress illumination spots.

The common reference plane (11s) is provided on the unit frame (11) that constitutes the lighting device (9), and the light guide (30) is a frame that forms a light source accommodating portion supported by the unit frame (11). (13) The diffused reflection surface (32) of the light guide (30) is held at the first position (d3) positioned from the common reference surface (11s) through the frame (13). By using the unit frame as a common reference plane by matching the light source mounting reference position with the light guide mounting reference position, the light source mounting position facing the end surface of the light guide (relative to the normal direction of the optical axis) The device is easy to assemble without adjusting the position.

Further, the common reference plane (11s) is provided in the unit frame (11) constituting the illumination device (9), and the unit frame (11) has positioning portions (11a, 11b) for positioning the circuit board (16). The circuit board (16) is formed and provided with positioning support parts (16a, 16b) supported by the positioning parts (11a, 11b) of the unit frame (11), thereby simply positioning the circuit board (16a, 16b). 16b) is attached to the positioning part (11a, 11b) of the unit frame using the light guide attachment reference, and the light source attachment position (position relative to the normal direction of the optical axis) facing the end face of the light guide is uniform. Can be combined, and the device assembly can be remarkably improved.

<Arrangement of the light source facing the light guide>
Next, it supplements regarding arrangement | positioning of the light source facing a light guide. As shown in FIGS. 16 and 17, the end surfaces (30a, 30b) that capture light, the diffuse reflection surface (32) that diffusely reflects the light captured from the end surfaces (30a, 30b), and the diffuse reflection surface (32). A light guide (30) including a light exit surface (33) for emitting diffusely reflected light toward an irradiation surface (R: see FIG. 2), and at least one end surface (30a, 30b) of the light guide (30) ), The light emitting surface (33) of the light guide (30) is formed with a circumferential surface (radius r), and the diffuse reflection surface (32) is the circle. It is disposed at a position where an optical axis normal (hx) exiting from the light exit surface (33) passes through the center (P1) of the circle forming the peripheral surface (radius r), and is mounted on the circuit board (16). The light source (40) is on the optical axis normal (hx) of the diffuse reflection surface (32) and the center of the circle ( 1) is arranged at the first light source mounting position (P2) displaced toward the light exit surface (33) with respect to 1), and the light source is located between the center of the circle formed by the circumferential surface and the light exit surface. The light quantity at both ends of the light guide can be made higher than the light quantity at the central part, and the optimal light quantity distribution for the illumination device mounted on the optical reading system image reading apparatus described above. Can be obtained.

Moreover, as shown in FIG. 9, the light emission surface (33) of the light guide (30) is formed of a circumferential surface (radius r),
The diffuse reflection surface (32) is disposed at a position where an optical axis normal line (hx) exiting from the light exit surface (33) passes through the center (P1) of the circle forming the circumferential surface (radius r). The light source (40) mounted on the circuit board (16) is composed of the first and second light sources, and the first light source (40) is the optical axis normal (hx) of the diffuse reflection surface (32). The second light source (40) is arranged at a first position (d3) displaced toward the light exit surface (33) with respect to the center (P1) of the circle, and the second light source (40) has its optical axis normal (hx) It is arranged at the second position (d2) which is displaced on the diffuse reflection surface (32) side with respect to the center (P1) of the circle, and the light quantity is increased nearly twice and the light is guided. The amount of light at both ends of the body can be made higher than the amount of light at the center, and an optimum light amount distribution can be obtained for an illumination device mounted on an optical reduction system image reading device. Only the without optimal added document by bright illumination to the image reading apparatus of a so-called sheet-through mode equipped for reading while feeding automatically, can speed up the image reading speed.

In addition, regarding the arrangement of the light source facing the light guide, the following structure may be used.

First, the light source facing at least one end surface of the light guide with a predetermined interval is a light source facing the one end surface of the light guide with a predetermined interval in the embodiment shown in FIGS. 9 and 10 described above. However, instead of this reflecting plate, a new light source may be provided with the same structure as the light source on the one end surface of the light guide.

In addition, by adopting a configuration in which the position of the second light source positioned with respect to the first light source as a position reference can be adjusted, the spectral characteristics can be adjusted by finely adjusting the position with respect to the light amount deterioration due to the temporal change of the light source. The initial appropriate state can be obtained.

<Description of pseudo light source>
Next, the pseudo light source will be supplemented. As shown in FIG. 9A, the illumination device irradiates linear light onto the irradiation surface (R) serving as a reading surface by scattering and reflecting the light from the light source (40), and the light from the light source (40) is irradiated. A diffusion reflection surface (32) that forms a light scattering surface that scatters in a line direction along the irradiation surface (R), and light emission that emits light from the diffusion reflection surface (32) toward the irradiation surface (R). A light guide (30) having a surface (33), and a light source (40) disposed on one end surface (30L) of the light guide (30), the light source (40) being a light guide (30). The reflector (50) is attached to the other end surface (30R) of the light guide (30) via an adhesive (60) having a high light transmittance. By constructing a pseudo light source corresponding to the light source (40), the reflecting plate forming the pseudo light source is connected to the other end surface of the light guide through an adhesive material having high light transmittance. By sticking, like the light source disposed at a predetermined interval on one end surface of the light guide, a certain gap is generated between the reflector and the other end surface of the light guide by the adhesive material. As a result, the light environment between the light source and the pseudo light source becomes close, and a pseudo light source more similar to the light source can be created. Therefore, the illuminating device having this configuration is bright as in the case where the light sources are provided on both end faces of the light guide, and exhibits an excellent effect of obtaining the left and right spectral characteristics as linear light.

Furthermore, the reflecting plate (50) and the adhesive sheet (60) used for the pseudo light source are used as the reflecting plate that is cut in accordance with the outer shape of the other end face of the light guiding body (30), and the reflecting plate is used as the light guiding body. It is excellent in workability by being affixed to the other end surface of the light source, and it is reliably between the reflector (50) and the other end surface of the light guide (30) by simply affixing the reflector to the other end surface of the light guide. Since a certain gap can be provided, a gap can be formed between the reflector (50) and the light guide (39) by a simple method, and a light source is provided on each end face of the light guide. As in the case of the above, it is bright and has the effect of obtaining left and right uniform spectral characteristics as linear light.

In addition, it is good also as a structure which inclines the other end part (30R) pseudo | simulated by changing the thickness of an adhesive sheet, without inclining the edge part of the light guide (30) by the side of a pseudo light source.

<Isolation between reflector light sources>
Next, it supplements about isolation between the light sources by a reflector. As shown in FIGS. 11 and 12, the first light source (40) and the second light source (40) are separated from each other by the reflector (49), and the light irradiation region of the light guide (30) is separated. By separating the light entering the light guide (30) from the one end face (30a, 30b), the spectral characteristics of the light sources of the first and second light sources are individually regulated, and the optimum Light from the first and second light sources regulated by the spectral characteristics can be incident on the end face of the light guide only from the region regulated by the reflector, and illumination spots can be further suppressed.

<Frame body locking of light guide>
Next, it supplements regarding the frame locking of a light guide. As shown in FIGS. 7 and 9 (a) and 10, the light source (40) and the light from the light source (40) are guided along the illumination line direction, and the illumination areas (41a, 42a) are linear light. A light source (30) that illuminates the light source (40), and the light source (40) is disposed to face at least one end surface (30a, 30b) of the light guide (30), and the light guide (30) Includes an end face (30a, 30b) for capturing light, a diffuse reflection surface (32) for diffusing and reflecting light captured from the end face (30a, 30b), and an irradiation surface (for reflecting light diffusely reflected by the diffuse reflection surface (32)). R: a light exit surface (33) that emits toward the surface), and the light exit surface (33) is formed of a circumferential surface (radius r), and the diffuse reflection surface (32) is the circumference thereof. An optical axis normal line that exits from the light exit surface (33) through the center (P1) of the circle forming the surface (radius r) x) is an illuminating device disposed at a position where the light guide body (30) is formed, and includes a frame body (13) that houses the light guide body (30). The light guide body (30) has a diffuse reflection surface (32). A projection (30P) is formed on the side surface along the optical axis normal line (hx) to be formed and is locked to the frame (13) along the illumination line direction, and the light source (40 of the projection (30P)) ) Side end (32a) between the light source side end face (30a, 30b) of the diffuse reflection surface (32) and the light source side end face (30a, 30b) at the illumination line of the illumination area (41a, 42a). By forming in between, the reflected light reflected at the base end of the light entering the light guide from the light source is not disturbed by the protrusion, and the locking condition with the frame is maintained, In particular, there is little variation in the light amount distribution on the light source side end face in the illumination line of the illumination area. It is possible to suppress the more lighting spots.

[Industrial applicability]
The illumination apparatus according to the present invention can be used for apparatuses other than the above-described image reading apparatus. For example, the illumination apparatus can be used as an illumination apparatus for optical devices such as an optical microscope, a magnifying projector, and a projector, or a general household illumination apparatus. I can do it.

DESCRIPTION OF SYMBOLS 1 Apparatus housing 2 1st platen 3 2nd platen 5 Platen cover 6 Carriage 7 Condensing lens 8 Line sensor 9 Pulling fixing | fixed part 9 Light source unit 9a 1st light source body 9b 2nd light source body 10 Reflecting mirror 10a 1st mirror 10b 2nd Mirror (4th mirror)
10c 3rd mirror 10d 5th mirror 10e 6th mirror 10f 7th mirror 11 Unit frame 12 Guide shaft 13 Light source housing part 13a 1st housing part 13b 2nd housing part 14 Heat radiation member 15 Heat-resistant sheet 16 Circuit board 16b Circuit part 16d Resin Section 17 Pulling member 18 Reflector 19 Traveling drive means 21 Lead roller 22 Unloading roller 23 Paper feed stacker 24 Paper feed roller 25 Registration roller pair 27 Backup roller 28 Paper discharge roller 29 Paper discharge stacker 30 Light guide 30a First light guide 30b 2nd light guide 30N collar part 30P projection part 30S light guide side surface 30L one end surface 30R other end surface 31 reading opening 32 light scattering surface 33 light emission surface 40 light emitter (light source)
40a Anode 40b Cathode 41 First light emitter (white LED)
42 Second light emitter (white LED)
43 Lens cap 44 Power supply 45 Sensor circuit board 46 Pulley 47 Insulating mylar 48 Holding member 49 Reflector 49a Reflecting surface 49b Reflecting surface 50 Reflecting plate 60 Adhesive material A Image reading unit B Document feeding unit F1 Arrow F2 Arrow GL Rail member HP Home position Ld distance Ld1 distance Ld2 distance MO motor Mc carriage motor R reading surface W reading line width d gap dx offset amount ha arrow hb arrow hc outgoing light path direction hx normal line P1 light guide center P2 second light emitter center P3 first light emission Body center

Claims (10)

A light source and a light guide that guides light from the light source along the illumination line direction and illuminates the illumination area as linear light, and
The light source is disposed opposite to at least one end surface of the light guide;
The light guide is
An end surface for capturing light; a diffuse reflection surface for diffusing and reflecting light captured from the end surface; and a light exit surface for emitting light diffusely reflected by the diffuse reflection surface toward the irradiation surface, and the light exit surface is a circle. Formed on the circumference,
The diffuse reflection surface is an illuminating device that is disposed at a position that forms an optical axis normal that exits from the light exit surface through the center of a circle that forms the circumferential surface thereof,
A frame for storing the light guide;
The light guide body is a side surface along an optical axis normal line formed by the diffuse reflection surface, and forms a protrusion locked to the frame body along the illumination line direction,
An illumination device in which one end of the protrusion on the light source side is formed between the light source side end surface of the diffuse reflection surface and the light source side end surface of an illumination line of the illumination area. A reflector having a reflecting surface that reflects light from the light source toward one end surface of the light guide;
The light guide body is formed with a flange that abuts on the reflector on one end surface thereof,
The light source is attached to a circuit board on which the light source is mounted,
The lighting device according to claim 1, wherein the reflector is sandwiched between a collar portion of the light guide and the circuit board, and is held at a predetermined interval between the light source and the light guide. The lighting device according to claim 2, further comprising a holding member that sandwiches the reflector between the flange portion of the light guide and the circuit board. Both of the circuit boards of the light guide have a common reference plane,
The diffuse reflection surface of the light guide is held at a first position positioned from the common reference surface;
The circuit board is positioned from the common reference plane, and the light source is disposed at a second position facing one end face of the light guide,
4. The lighting device according to claim 2, wherein the light guide and the circuit board are held by the holding member via the reflector. The common reference plane is provided on the unit frame constituting the lighting device,
The light guide is housed in a frame supported by the unit frame;
The illumination device according to claim 4, wherein the diffuse reflection surface of the light guide is held at a first position positioned from the common reference surface via the frame. The common reference plane is provided on the unit frame constituting the lighting device,
The unit frame is formed with a positioning portion for positioning the circuit board,
The lighting device according to claim 4, wherein the circuit board includes a positioning support portion supported by a positioning portion of the unit frame. The light exit surface of the light guide is formed by a circumferential surface,
The diffuse reflection surface is disposed at a position that forms an optical axis normal that exits from the light exit surface through the center of a circle that forms the circumferential surface thereof,
The light source mounted on the circuit board is:
The illuminating device according to claim 1, wherein the illuminating device is disposed on the optical axis normal line of the diffuse reflection surface and at a position displaced toward the light exit surface side with respect to the center of the circle. The light exit surface of the light guide is formed by a circumferential surface,
The diffuse reflection surface is disposed at a position that forms an optical axis normal that exits from the light exit surface through the center of a circle that forms the circumferential surface thereof,
The light source mounted on the circuit board consists of first and second light sources,
The first light source is disposed on the optical axis normal line of the diffuse reflection surface and at a first position displaced toward the light exit surface side with respect to the center of the circle,
2. The illumination device according to claim 1, wherein the second light source is disposed at a second position on the normal axis of the optical axis and displaced toward the diffuse reflection surface with respect to the center of the circle. The illumination device according to claim 6, wherein the first and second light sources are configured such that an irradiation region is isolated by the reflector, and light entering the light guide is separated from one end face of the light guide. An image reading apparatus comprising: a platen for placing a reading document; a light source for illuminating the reading document placed on the platen; and a light receiving unit for receiving reflected light from the reading document illuminated by the light source. There,
The image reading apparatus comprising the illumination device according to claim 1.