JP2015050583A - Light source device and image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the degradation of an image caused by flare light, while obtaining a sufficient light quantity for reading, without causing the problem of excessive heat generation, in an image reader using a light guide body.SOLUTION: A light source device 10 includes a light source 120, light guide bodies 171 and 172 reflecting light made incident from the light source 120 toward an emission surface 17, and a holding member 19 holding the light guide bodies 171 and 172. The holding member 19 is provided to cover the side surface part and reflection surface 15 of the light guide bodies 171 and 172 extending in the optical axis direction of the light source 120, except the emission surface 17 of the light guide bodies 171 and 172. The outer surface of the holding member 19 is used as a reflection suppression part suppressing light reflection and the inner surface of the holding member 19 is used as a reflection part reflecting the light made incident from the light source 120.

Description

  The present invention relates to a light source device and an image reading device, and more particularly, to light irradiation toward an illumination object and handling of reflected light from the illumination object incident on the light guide.

  In an image forming apparatus such as a multifunction machine, as a light source unit of an image reading apparatus such as a scanner, a rod-shaped resin light guide and an LED that emits light from the side in the length direction of the light guide to the inside of the light guide Some use a line light source that combines the above. The light source unit illuminates the document to be read in a line shape in accordance with the reading of the line sensor. For this purpose, a light reflection or light scattering pattern is provided on the surface facing the exit surface for emitting light from the light guide, and the light incident on the light guide toward the exit surface is deflected by the pattern, Line-shaped illumination light is emitted in a direction toward the document. For example, in Patent Document 1 below, in a sidelight type illumination unit, in order to realize a reduction in size of the apparatus and to easily irradiate light on a document from both sides, two diffusion surfaces are provided in one light guide. An arranged two-branch linear light source device has been proposed.

JP 2008-216409 A

  In the image reading apparatus having the light source device as described above, the reflected light of the light irradiated from the light guide onto the document surface is reflected on the document surface by a CCD or the like via a mirror disposed facing the document surface. The light is guided to a photoelectric conversion unit, and the photoelectric conversion unit converts the reflected light into an electrical signal, thereby acquiring image information obtained by reading the document surface.

  However, the light source device disclosed in Patent Document 1 includes one set of a light source and a light guide, and a reflection plate provided at a position facing the reading optical axis with the light from the light source via the conductor. The reading surface is irradiated with reflected light from the reflecting plate. In this configuration, since the irradiation position with respect to the original surface is arranged far from the optical axis (original reading position), the influence of flare light is relatively small. However, since the original surface is irradiated by one light guide, it is necessary to use a high-luminance LED or the like as a light source in order to obtain a sufficient amount of light for reading. In the light irradiation by one light guide, there is a limit to the amount of light obtained. In addition, if a very bright LED is used, the heat generation becomes very high, and there is a concern about shortening the life of the LED or deformation of the light guide. .

  The present invention has been made to solve the above-described problems. In an image reading apparatus using a light guide, an image by flare light is obtained while obtaining a sufficient amount of light for reading without causing a problem of excessive heat generation. The purpose is to prevent deterioration.

  A light source device according to an aspect of the present invention is provided on at least one of a light source that irradiates light and both ends in a longitudinal direction, and an incident surface on which the light emitted from the light source is incident when the light source is attached. And forming a part of a side surface portion extending in the optical axis direction of light incident from the incident surface, extending in the optical axis direction at a position facing the exit surface, an exit surface for emitting the incident light, A light guide made of a light transmissive member having a plurality of light reflection patterns formed to reflect the incident light toward the exit surface, and extending in the optical axis direction, and at least the light guide Except for the light exit area on the exit surface, the side surface portion extending in the optical axis direction and the reflective surface are provided so that the outer surface is a reflection suppression portion that suppresses light reflection, and the inner surface is the incident light. It is a reflection part to reflect A reflected light adjustment member, those having a.

  For example, a light guide and a light source are arranged on both sides of the reading optical axis with respect to the reading surface (document surface) to irradiate the document surface, and the reflected light is guided to an imaging unit including a photoelectric conversion device by a reflection mirror. When the light source device according to the present invention is used for an image reading apparatus that reads a document image, a part of the reflected light emitted from the light guide and irregularly reflected on the document surface is directed toward the light guide that is disposed to face the light guide. However, since the reflected light is incident on the reflection suppressing portion in the reflected light adjusting member provided on the side surface portion of the light guide body disposed so as to face the light, the light reflected from the light guide body toward the reflection mirror. The amount of is reduced. For this reason, if the light source device according to the present invention is used, the amount of light incident on the imaging device as flare light can be reduced, and accurate image reading faithful to the document reflectance can be performed. Further, according to the light source device of the present invention, since the two light guides and the light source are arranged as described above and the document surface is read, image degradation due to flare light is small, so that flare light is reduced. Since it is not necessary to adopt a configuration in which a single light guide and light source with a large amount of irradiation light and a reflecting plate arranged opposite to the light guide are used, there is a problem that excessive heat is generated by using one light guide and light source. Does not occur.

  According to the present invention, in a light source device using a light guide, image deterioration due to flare light can be prevented while obtaining a sufficient amount of light for reading without causing the problem of excessive heat generation.

1 is a front sectional view showing a structure of an image forming apparatus having a light source device according to an embodiment of the present invention in an image reading apparatus. It is an internal side view which shows schematic structure of an image reading apparatus. It is a perspective view which shows a light source device, and is a figure which showed the internal structure. In a light source device, it is a figure which shows a mode that the light reflection pattern of a reflective surface reflects incident light toward an output surface.

  Hereinafter, a light source device according to an embodiment of the present invention and an image reading apparatus including the same will be described with reference to the drawings. FIG. 1 is a front cross-sectional view showing the structure of an image forming apparatus having a light source device according to an embodiment of the present invention in an image reading apparatus.

  An image forming apparatus 1 according to an embodiment of the present invention is a multifunction machine having a plurality of functions such as a copy function, a printer function, a scanner function, and a facsimile function. The image forming apparatus 1 is configured by including an operation unit 47, an image forming unit 12, a fixing unit 13, a paper feeding unit 14, a document feeding unit 6, an image reading device 5, and the like in an apparatus main body 11A.

  The operation unit 47 receives instructions such as an image forming operation execution instruction and a document reading operation execution instruction from the operator regarding various operations and processes that can be executed by the image forming apparatus 1. The operation unit 47 includes a display unit 473 that displays operation guidance to the operator.

  When the image forming apparatus 1 performs an original reading operation, the image reading apparatus 5 optically processes an original fed by the original feeding unit 6 or an image of an original placed on contact glass (original placing glass) 161. Read and generate image data. Image data generated by the image reading device 5 is stored in a built-in HDD or a computer connected to a network.

  When the image forming apparatus 1 performs an image forming operation, the image data generated by the document reading operation, the image data received from a user terminal device such as a computer or a smartphone connected to a network, or stored in a built-in HDD. The image forming unit 12 forms a toner image on a recording sheet P as a recording medium fed from the sheet feeding unit 14 based on the image data and the like. The image forming units 12M, 12C, 12Y, and 12Bk of the image forming unit 12 include a photosensitive drum, a developing device that supplies toner to the photosensitive drum, a toner cartridge (not shown) that stores toner, and a charging device. , An exposure device and a primary transfer roller 126 are provided.

  When performing color printing, the magenta image forming unit 12M, the cyan image forming unit 12C, the yellow image forming unit 12Y, and the black image forming unit 12Bk of the image forming unit 12 each receive image data. A toner image is formed on the photosensitive drum 121 by charging, exposure, and development processes based on the image composed of each color component, and the toner image is transferred to the driving roller 125a and the driven roller 125b by the primary transfer roller 126. The image is transferred onto the intermediate transfer belt 125 that is stretched.

  The intermediate transfer belt 125 is driven by a driving roller 125 a in a state where an image carrying surface on which a toner image is transferred is set on the outer peripheral surface thereof and in contact with the peripheral surface of the photosensitive drum 121. The intermediate transfer belt 125 travels endlessly between the driving roller 125a and the driven roller 125b while being synchronized with each photosensitive drum 121.

  The toner images of the respective colors transferred onto the intermediate transfer belt 125 are superimposed on the intermediate transfer belt 125 with the transfer timing adjusted to become a color toner image. The secondary transfer roller 210 conveys the color toner image formed on the surface of the intermediate transfer belt 125 from the sheet feeding unit 14 through the conveyance path 190 at the nip N between the intermediate transfer belt 125 and the driving roller 125a. The recording sheet P is transferred. Thereafter, the fixing unit 13 fixes the toner image on the recording paper P to the recording paper P by thermocompression bonding. The recording paper P on which the color image has been formed after completion of the fixing process is discharged to a discharge tray 151.

  The paper feed unit 14 includes a plurality of paper feed cassettes. The control unit (not shown) rotates the pickup roller 145 of the paper feed cassette in which the recording paper of the size specified by the instruction from the operator is rotated, so that the recording paper P stored in each paper feed cassette is loaded. It is conveyed toward the nip portion N.

  Next, the configuration of the image reading apparatus will be described. FIG. 2 is an internal side view showing a schematic configuration of the image reading device 5.

  As shown in FIG. 2, the image reading device 5 includes an optical scanning device 7 and an imaging unit 8.

  The optical scanning device 7 includes a first optical system unit 71 and a second optical system unit 72.

  The first optical system unit 71 includes a light source device 10 and a first mirror 711. The light source device 10 is disposed opposite to the contact glass 161 so as to irradiate light toward the reading surface (document surface) of the document (upward in FIG. 2). The light source device 10 includes two light guides 171 and 172, and a light source 120 and a holding member 19 disposed on the light guides 171 and 172, respectively. The light guides 171, 172, the light source 120, and the holding member 19 are disposed on the support member 70 of the first optical system unit 71.

  The light guides 171 and 172 are transparent rod-shaped members. The light guides 171 and 172 extend in the depth direction in FIG. The direction in which the light guides 171 and 172 extend is the main scanning direction during document reading.

  The light source 120 is provided at each end (both ends) of the light guides 171 and 172 in the length direction. The light source 120 emits light toward the inside of the light guide with the length direction of the light guide attached as an optical axis. The reading surface extends in the length direction of the light guides 171 and 172. The light source 120 irradiates the reading surface from the oblique lower side in FIG. 2 with respect to the reading surface by light reflection of the light guides 171 and 172. A light guide is disposed on both sides of the reading optical axis A in the sub-scanning direction, a light guide 171 is provided on one side of the reading optical axis A, and a light guide 172 is provided on the other side. .

  The light guides 171 and 172 are each held by a holding member (an example of a reflected light adjusting member) 19 and attached to the support member 70. The holding member 19 covers the lower part from the side part of the light guide to be held.

  The first mirror (an example of a reflection mirror) 711 receives the reflected light from the original reading surface of the light irradiated by the light source device 10 on the original placed on the contact glass 161, and changes the direction of the reflected light in the horizontal direction. Let The first mirror 711 is disposed below the contact glass 161 and at a position of the reading optical axis A orthogonal to the reading surface. That is, the light guides 171 and 172 and the light source 120 are arranged such that the reading optical axis A orthogonal to the reading surface is directed to the first mirror 711 arranged immediately below the reading surface. The light source device 10 and the first mirror 711 are attached to the support member 70.

  The second optical system unit 72 includes a second mirror 721 and a third mirror 722. The second mirror 721 receives the light reflected by the first mirror 711 of the first optical system unit 71 and further changes the direction downward substantially vertically. The third mirror 722 further changes the direction of the light reflected by the second mirror 721 substantially horizontally and guides the light toward the imaging unit 8. The second mirror 721 and the third mirror 722 are attached to a support member (not shown). The second mirror 721 and the third mirror 722 are an example of a reflection mirror.

  The light source device 10 and each of the mirrors provided in the first optical system unit 71 and the second optical system unit 72 are elongated and extend in the main scanning direction with the same length as the contact glass 161 (document reading width). It is made into a shape.

  Inside the image reading device 5, an unillustrated moving rail for guiding the movement of the optical scanning device 7 in the direction of the arrow is provided. As a result, the optical scanning device 7 including the first optical system unit 71 and the second optical system unit 72 is parallel to the surface of the contact glass 161 so as to read image information on the entire reading surface of the document placed on the contact glass 161. In addition, it is possible to reciprocate in the sub-scanning direction (direction orthogonal to the main scanning direction), that is, the arrow direction shown in FIG.

  The imaging unit 8 is fixed to the lower part inside the image reading device 5. The imaging unit 8 includes an imaging lens 81 that is an optical member, and a line sensor 82 that is an imaging element. Reflected light from the reading surface of the document reflected by the third mirror 722 of the second optical system unit 72 is incident on the imaging lens 81. The imaging lens 81 forms an image of the reflected light on the surface of the line sensor 82 provided on the downstream side of the optical path. The line sensor 82 generates a voltage indicating the amount of light according to the amount of received light, that is, converts the optical information obtained by the light receiving element into an electrical signal and outputs it to a control unit (not shown). In this manner, the line sensor 82 reads an image of a document to be read by the image reading device 5.

  Next, the light source device 10 provided in the image reading device 5 will be described. FIG. 3 is a perspective view showing a light guide and a light source provided in the light source device 10, and shows an internal configuration. FIG. 4 is a diagram illustrating a state in which the light reflection pattern of the reflection surface 15 reflects incident light toward the emission surface.

  As described above, the light source device 10 includes the two light guides 171 and 172, and the light source 120 and the holding member 19 disposed in each of the light guides 171 and 172. Since the structures of the light guides 171 and 172 are the same, FIG. 3 shows the light guide 171 and shows one end portion in the length direction.

  The light guide 171 extends in this direction with the optical axis direction of the light incident on the inside of the light guide 171 from the light sources 120 provided at both ends in the length direction as the longitudinal direction. Since the light guide 171 extends in the main scanning direction as described above, the optical axis direction coincides with the main scanning direction. The light guide 171 is made of, for example, a resin light transmissive member, and reflects light incident from the light source 120 toward a certain direction (direction toward the emission surface 17) by the reflection surface 15. The light source 120 may be provided only at one end of the light guide 171 in the length direction. In the present embodiment, a description will be given using an example in which light sources 120 are provided at both ends of the light guide 171 in the length direction.

  The light guide 171 is formed by the entrance surface 18, the exit surface 17, and the reflection surface 15.

  The incident surface 18 has at least one side surface at both ends in the longitudinal direction of the light guide 171 as the incident surface. In the present embodiment, as described above, a mode in which the side surfaces of both end portions are the entrance surfaces 18 will be described. A light source 120 is attached to each incident surface 18. The light emitted from the light source 120 enters the light guide 171 from the incident surface 18.

  The emission surface 17 extends in the main scanning direction and forms part of the side surface of the light guide 171. In the present embodiment, the emission surface 17 forms the upper surface portion of the light guide 171. The light that has entered the light guide 171 from the incident surface 18 is reflected by the reflecting surface 15 and is emitted from the light emitting surface 17 to the outside of the light guide 171.

  The reflection surface 15 extends in the main scanning direction at a position facing the emission surface 17. In the present embodiment, the reflecting surface 15 forms the lower surface portion of the light guide 171. As shown in FIG. 4, a plurality of light reflection patterns 16 that reflect light incident from the incident surface 18 toward the output surface 17 are formed on the reflective surface 15. The light reflection pattern 16 is integrally formed of the same material as the light guide 171.

  The light source 120 includes, for example, an LED 121. The light source 120 is attached to the outer surface of the incident surface 18 of the light guide 171. In this embodiment, an example in which six LEDs 121 are provided as the light source 120 is shown. The irradiation direction (optical axis direction) of the light emitted from the light source 120 toward the inside of the light guide 171 from the incident surface 18 is the length direction of the light guide 171, that is, the main scanning direction.

  When the light reflection pattern 16 composed of an inverted V-shaped prism protruding toward the emission surface 17 is formed on the reflection surface 15, the pitch between the light reflection patterns 16 in the main scanning direction, the light reflection pattern 16. By varying the height, width (length in the sub-scanning direction), and the like, the amount of light reflected by the reflecting surface 15 of the light reflecting pattern 16 in the direction of the emitting surface 17 is adjusted. For this reason, it is possible to make the illumination light emitted from each position in the main scanning direction uniform by adjusting the pitch, height, width, etc. of the light reflecting pattern 16 arranged at each position in the main scanning direction. It has become.

  As shown in FIG. 2, the light guides 171 and 172 configured as described above are arranged to face each other and irradiate the reading surface from below.

  Subsequently, the holding member 19 will be described. The holding member 19 is a member that holds the light guide 171 as described above. As shown in FIG. 3, the holding member 19 is an outer surface of the light guide 171 excluding the emission surface 17 of the light guide 171, and covers an area that covers the side surface portion 20 of the light guide 171 and the reflection surface 15. Be placed. The holding member 19 extends in the length direction of the light guide body 171, that is, in the optical axis direction of the light irradiated from the light source 120 to the inside of the light guide body 171 while covering the side surface portion 20 portion and the reflection surface 15. , And arranged from one end portion to the other end portion in the length direction. In the holding member 19, the outer side surface 191 is a reflection suppression unit that suppresses light reflection, and the inner side surface 192 is a reflection unit that reflects light.

  In the image reading apparatus 5 having the configuration shown in FIG. 2, the light emitted from the light guides 171 and 172 is irregularly reflected on the reading surface. At this time, a part of the light reflected from the reading surface of the light emitted from one light guide is directed toward the other light guide that is disposed to face the other. If the light guide does not have the holding member 19, the reflected light directed to the other light guide is reflected by the side surface of the light guide and a part thereof is directed to the first mirror 711. The light enters the imaging unit 8. When the light reflected from the light guide is incident on the imaging unit 8, it becomes flare light and cannot be read faithfully to the document reflectance, resulting in image degradation. For example, when the white background portion is surrounded by a black background region, the flare light has a low output from the imaging unit 8 (becomes dark), and conversely, when the black background portion is surrounded by the white background region, the output from the imaging unit 8 increases. This causes a phenomenon of becoming whitish, and causes a problem that the fog and fine lines in the white background around the black background are interrupted. Further, in the case of reading a color image, there is a possibility that the original color tone that should be obtained by reading changes.

  However, in this embodiment, each of the light guides 171 and 172 has the holding member 19, and the reflected light directed to the other light guide is incident on the outer surface 191, and thus reflected light on the reading surface. Is reflected by the light guides 171 and 172, and the amount of light traveling toward the first mirror 711 is reduced. Accordingly, if the light source device 10 according to the present embodiment is used, the amount of light incident on the imaging unit 8 as flare light can be reduced, and the image reading device 5 can perform accurate image reading faithful to the document reflectivity. It can be performed. Further, since the inner side surface 192 can reflect the light incident on the inside of the light guide from the light source 120 and leaked from the light guide, it can be guided to the exit surface. And image reading can be performed.

  Further, according to the light source device 10 according to the present embodiment, even if the configuration in which the two light guides 171 and 172 and the light source 120 are arranged to read the reading surface (document surface) as described above, flare light is used. Since there is little image deterioration, it is not necessary to introduce a configuration using a single light guide and a light source with a large amount of light to reduce flare light, so that heat generation by one light guide and the light source becomes excessive. There is no problem.

  The holding member 19 will be further described. For example, the holding member 19 has an outer surface 191 black and an inner surface 192 white. As described above, since the outer surface 191 has a role of reducing the reflected light of the light incident on the outer surface 191, it is preferable that the light reflectivity is black which is relatively low compared to other colors. On the other hand, by making the inner surface 192 white, the light reflectivity by the inner surface 192 is increased, and the light leaking from the light guides 171 and 172 can be guided to the emission surface 17 more efficiently.

  Further, the holding member 19 preferably has an inner surface 192 having a light reflectance of 80% or more and an outer surface having a light reflectance of 20% or less. According to this configuration, the reflected light of the light incident on the outer surface 191 can be reduced more accurately, and the light leaking from the light guides 171 and 172 can be guided to the emission surface 17 more efficiently.

  Still further, the holding member 19 preferably has a non-glossy outer surface 191. According to this, the reflected light of the light incident on the outer surface 191 can be reduced more accurately.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, in each of the above embodiments, the holding member 19 covers the side surface portion 20 and the reflecting surface 15 other than the light emission surface 17 of the light guides 171 and 172. However, the holding member 19 is at least from the reading surface. Of the light guides 171 and 172 that reflect the reflected light in the direction in which the reflected light can enter the imaging unit 8 may be provided. For example, even if it is the exit surface 17, if there is a portion where reflected light from the reading surface is incident, the holding member 19 may further cover the incident portion. In the above embodiment, the holding member 19 is attached in contact with the light guides 171 and 172. However, the present invention is not limited to this, and the holding member 19 has a gap with respect to the light guides 171 and 172. May be attached.

  In each of the above embodiments, the light source 120 including the LED 121 is shown. However, light is emitted in the main scanning direction from the side surface serving as the end of the light guides 171 and 172 toward the inside of the light guide 171. Any LED can be used as long as it can emit light.

  Also, the configuration and processing shown in each of the above embodiments using FIGS. 1 to 4 are only one embodiment of the present invention, and the configuration and processing of the present invention are not limited to this.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 5 Image reading apparatus 7 Optical scanning apparatus 10 Light source apparatus 12 Image forming part 120 Light sources 171, 172 Light guide body 16 Light reflection pattern 17 Output surface 18 Incident surface 19 Holding member 20 Side surface portion 70 Support member 71 First optical System unit 711 first mirror 72 second optical system unit 721 second mirror 722 third mirror 8 imaging unit 81 imaging lens 82 line sensor

Claims (8)

A light source that emits light;
Provided on at least one of both ends in the longitudinal direction, the incident surface on which the light source is attached and the light emitted from the light source is incident on the inside,
Forming a part of a side surface portion extending in the optical axis direction of light incident from the incident surface, and an exit surface for emitting the incident light;
A reflection surface formed with a plurality of light reflection patterns that extend in the optical axis direction at a position facing the emission surface and reflect the incident light toward the emission surface, and extend in the optical axis direction A light guide made of a light transmissive member;
Except at least the light exit region on the exit surface of the light guide, the side surface portion extending in the optical axis direction and the reflection surface are provided to be covered, the outer surface is a reflection suppression unit that suppresses light reflection, and the inner surface is A light source device comprising: a reflected light adjusting member that is a reflecting portion that reflects the incident light.   The light source device according to claim 1, wherein the reflected light adjusting member has a black outer surface and a white inner surface.   The light source device according to claim 1, wherein the reflected light adjusting member has a light reflectance of 80% or more on the inner side surface and a light reflectance of 20% or less on the outer side surface.   The light source device according to claim 1, wherein the reflected light adjusting member has a non-glossy surface on the outer surface.   The light source device according to any one of claims 1 to 4, wherein side surfaces of both end portions of the light guide body in the optical axis direction are the entrance surfaces.   The light guide body and the light source provided on the light guide body are respectively disposed on both sides of the reading optical axis, and the reading target is irradiated by both the light guide bodies. A light source device according to claim 1. The light source device according to claim 6;
An imaging unit that receives light reflected by the reading object from the light source emitted from the light guide and converts it into an electrical signal, and acquires image information of the reading object;
An image reading apparatus comprising: a reflection mirror that reflects reflected light from the reading object toward the imaging unit.   The reflected light adjusting member of the light guide is provided at least on the side surface portion of the light guide that reflects reflected light from the reading object in a direction in which the light can be incident on the imaging unit. Item 8. The image reading device according to Item 7.

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