JP2014192885A - Illumination device, image reading device including the same, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to stably adjust the distance between an incidence surface of a light guide body and a light source, and prevent the contact between the incidence surface and the light source due to the thermal expansion of the light guide body.SOLUTION: An illumination device 50 irradiates a document sheet arranged on contact glass with light as a focal point. The illumination device 50 includes a light source 51, a first light guide body 52A and second light guide body 52B, and a distance regulating unit 8. The light source 51 emits illumination light that is made incident on incidence surfaces of the first light guide body 52A and second light guide body 52B along a first direction. The first light guide body 52A and second light guide body 52B respectively include a first reflection surface 57A and second reflection surface 57B that emit the light to irradiate the document sheet. The distance regulating unit 8 makes it possible to adjust the distance between the light source 51 and the incidence surfaces, and prevents the incidence surfaces from contacting the light source 51 in association with the thermal expansion of the first light guide body 52A and second light guide body 52B in the first direction.

Description

  The present invention relates to an illumination device using a light guide that guides illumination light emitted from a light source, and to an image reading device and an image forming device including the illumination device.

  2. Description of the Related Art In an image forming apparatus such as a scanner or a copying machine, an illuminating device that irradiates light on a document sheet is used to optically read an image on a document sheet placed on a reading surface. In recent years, an LED (Light Emitting Diode) having an advantage of high luminous efficiency has been adopted as a light source of the lighting device. In this type of illumination device, it is necessary to illuminate the original sheet in a line shape. However, since the LED is a point light source, a linear illumination light is generated by combining a bar-shaped light guide and the LED. The light guide is disposed at one end of the light guide and is incident on which illumination light emitted from the LED is incident; a strip-shaped emission surface that extends along the longitudinal direction of the light guide and emits the illumination light; ,have.

  Japanese Patent Application Laid-Open No. 2004-228688 discloses a technique including a single light guide and a reflecting plate extending in parallel with the light guide when illuminating a document sheet. The light guide has two exit surfaces, and light emitted from one of the exit surfaces is directly applied to the document sheet. Further, the light emitted from the other emission surface is reflected by the reflecting plate and then irradiated onto the original sheet. As a result, the original sheet is irradiated with light from two directions intersecting each other.

JP 2008-216409 A

  However, in the illumination device described in Patent Document 1, when a larger amount of light is required, the light guide body may thermally expand when the light emission amount of the LED is increased. In this case, the distance between the LED and the incident surface of the light guide varies, and the amount of light applied to the object to be irradiated may change. Furthermore, there has been a problem that the incident surface of the light guide is in contact with the LED, and the LED is deformed and broken.

  The present invention has been made in view of the above circumstances, the distance between the incident surface of the light guide and the light source can be stably adjusted, and the incident surface and the light source due to thermal expansion of the light guide. An object of the present invention is to provide an illuminating device that prevents the contact of the light source, and an image reading apparatus and an image forming apparatus using the same.

  An illuminating device according to one aspect of the present invention is an illuminating device that irradiates an object to be irradiated arranged on a predetermined arrangement surface, and has a rod-like shape that is long in a first direction. An incident surface disposed at one end portion on which light is incident along the first direction; and an emission surface extending along the first direction and emitting the light in a direction intersecting the first direction. A light guide for irradiating the irradiated object with light, a light source arranged to face the incident surface of the light guide and emitting illumination light incident on the incident surface, the light source and the incident surface And a distance regulating portion that prevents the incident surface from coming into contact with the light source due to thermal expansion in the first direction of the light guide. And

  According to this configuration, the illumination light emitted from the light source is incident on the incident surface of the light guide, and then irradiated on the irradiated object from the output surface. In addition, the distance regulating unit can adjust the distance between the light source and the incident surface of the light guide, and prevents the incident surface from coming into contact with the light source due to thermal expansion in the first direction of the light guide. For this reason, the distance between the light source and the incident surface of the light guide is adjusted in accordance with the variation in the light emission amount of the light source, and the amount of light applied to the irradiated object can be adjusted. Further, even when the light guide body is thermally expanded in the first direction as the light source generates heat, the incident surface does not come into contact with the light source, and deformation and breakage of the light source are prevented.

  In the above configuration, the light guide includes an opening through which the one end is inserted, the first support portion that supports the one end by exposing the incident surface to the outside of the opening, and the guide A second support portion for fixing the other end portion of the light body opposite to the one end portion in the first direction; and an incident surface disposed at a distance in the first direction with respect to the first support portion. A light source support part that supports the light source so as to face the light source, and the distance between the first support part and the light source support part is adjusted, whereby the light source and the incident surface It is desirable to adjust the distance between them.

  According to this configuration, the one end portion of the light guide is supported by the first support portion. The other end of the light guide is fixed to the second support. In addition, the light source is supported by a light source support part that is spaced from the first support part. And the distance between a light source and an entrance plane is adjusted by adjusting the distance between a 1st support part and a light source support part. For this reason, the distance between the light source and the incident surface is set stably.

  In the above configuration, the distance restricting portion includes a screw head disposed on the opposite side of the first support portion with respect to the light source support portion, and penetrates the light source support portion to the first support portion. Positioning that is rotatably mounted on the screw between a screw to be fastened, a screw opening that is opened in the light source support, and through which the screw is inserted, and the light source support and the first support A positioning nut, and a biasing spring that is disposed between the screw head of the screw and the light source support portion and biases the light source support portion toward the first support portion. It is desirable that the distance between the light source and the incident surface is changed by moving in the direction of the rotation axis of the screw.

  According to this configuration, the light source support portion is biased toward the first support portion by the biasing spring. At this time, the light source support is brought into contact with a positioning nut that is rotatably mounted on the screw. And the distance between a light source and an entrance plane changes because the positioning nut is moved in the rotating shaft direction of the screw. Therefore, the distance can be easily adjusted by moving the positioning nut.

  In the above configuration, a hole portion that is fixed to the first support portion side of the light source support portion and through which the illumination light emitted from the light source passes, and a contacted portion that is disposed so as to surround the hole portion, A spacer disposed between the incident surface and the light source, wherein the light guide body is thermally expanded in the first direction, and the incident surface presses the contacted portion of the spacer. Then, it is desirable that the light source support part is moved in a direction away from the first support part against the urging force of the urging spring.

  According to this configuration, when the light guide body is thermally expanded in the first direction due to heat generated by the light source, the incident surface presses the contacted portion of the spacer. At this time, the light source support portion is moved in a direction away from the first support portion against the biasing force of the biasing spring. Therefore, the distance between the light source and the incident surface is kept constant by the spacer. In addition, since the incident surface strongly contacts the spacer, the spacer or the light guide is prevented from being damaged.

  In the above configuration, the light guide has a rod-like shape that is long in the first direction, is disposed at one end of the first direction, and has a first incident surface on which light is incident along the first direction; A first emission surface that extends along the first direction and emits the light in a second direction intersecting the first direction, and irradiates the irradiated object with light from the second direction. A light guide and a rod-like shape that is long in the first direction, are arranged adjacent to the first incident surface at the one end portion in the first direction, and light is incident along the first direction. Two incident surfaces, and a second emission surface that extends along the first direction and emits the light in a third direction that intersects the first direction and the second direction. A second light guide for irradiating the irradiated object with light, wherein the light source is the first incident of the first light guide. A first light source that emits illumination light that is incident on the first incident surface, and is disposed opposite to the second incident surface of the second light guide, and is disposed on the second incident surface. And a second light source that emits incident illumination light.

  According to this configuration, the light emitted from the two light sources is irradiated to the irradiated object from different directions. For this reason, it is possible to irradiate the irradiated object with a large amount of light. Moreover, the light quantity of each light source is suppressed low, and the amount of heat generated by each light source is reduced.

  In the above configuration, in a cross-sectional view intersecting with the first direction, the second direction is a direction from the one arrangement surface side toward the irradiated object with respect to a normal line orthogonal to the arrangement surface, The third direction is preferably a direction from the other arrangement surface side toward the irradiation object with respect to the normal line.

  According to this configuration, it is possible to stably irradiate the irradiated object from both sides of the normal line.

  Said structure WHEREIN: The said to-be-irradiated object is arrange | positioned in the focus position of the light emitted from a said 1st light guide and a said 2nd light guide, Comprising: In the said sectional view, a said 1st light guide It is desirable that the triangle connecting the body, the second light guide, and the focal point is an equilateral triangle or an isosceles triangle having the focal point as a vertex.

  According to this configuration, uniform light can be emitted from the first light guide and the second light guide to the irradiated object.

  An image reading apparatus according to another aspect of the present invention is configured to receive any one of the above-described illumination device that irradiates illumination light on the original sheet as the irradiation object, and reflected light from the original sheet. A light receiving device that converts the light into an electric signal.

  According to this configuration, the distance between the light source and the incident surface of the light guide is adjusted according to variations in the light emission amount of the light source, and the amount of light applied to the document sheet can be adjusted. Further, even when the light guide body is thermally expanded in the first direction as the light source generates heat, the incident surface does not come into contact with the light source, and deformation and breakage of the light source are prevented. As a result, the original sheet is stably irradiated with light, and an image on the original sheet is suitably read by the image reading apparatus.

  An image forming apparatus according to another aspect of the present invention includes the image reading apparatus described above and an image forming unit that forms an image on a sheet based on image data output from the image reading apparatus. It is characterized by.

  According to this configuration, the original sheet is stably irradiated with light, and the image on the original sheet is preferably read by the image reading apparatus. Furthermore, an image is stably formed on the sheet based on the image data of the original sheet.

  According to the present invention, the distance between the incident surface of the light guide and the light source can be stably adjusted, and the illumination device prevents contact between the incident surface and the light source due to thermal expansion of the light guide, and An image reading apparatus and an image forming apparatus using the same are provided.

1 is a cross-sectional view illustrating a schematic configuration of an image reading apparatus and an image forming apparatus according to an embodiment of the present invention. It is a perspective view which shows the illuminating device which concerns on one Embodiment of this invention. It is a perspective view which shows the illuminating device which concerns on one Embodiment of this invention. It is a perspective view which shows the light guide which concerns on one Embodiment of this invention. It is sectional drawing of a light guide. It is typical sectional drawing of the illuminating device which concerns on one Embodiment of this invention. It is a perspective view of the illuminating device which concerns on one Embodiment of this invention. It is a perspective view of the illuminating device which concerns on one Embodiment of this invention. It is sectional drawing of the illuminating device which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view showing an internal structure of an image forming apparatus 1 according to an embodiment of the present invention. Here, as the image forming apparatus 1, a so-called in-body discharge type copier is illustrated. The apparatus to which the illumination apparatus according to the present invention is applied is not limited to a copying machine, and may be, for example, a scanner apparatus, a facsimile apparatus, or a multifunction machine.

  The image forming apparatus 1 includes a housing 2 having a substantially rectangular parallelepiped housing structure and having an in-cylinder space (in-cylinder discharge unit 24). The housing 2 includes a lower housing (device main body 21) that accommodates various devices for image formation, an upper housing (image reading device 22) disposed above the device main body 21, and the device main body 21. And a connecting housing 23 that connects the image reading device 22. The image reading device 22 optically reads an image on a document sheet and generates image data corresponding to the document image. The apparatus main body 21 performs a process of forming a toner image on the sheet based on the image data. Between the apparatus main body 21 and the image reading apparatus 22, an in-body discharge unit 24 that discharges a sheet after image formation is provided. The connection housing 23 is disposed on the right side surface of the housing 2 and is provided with a discharge port 961 for discharging the sheet to the in-body discharge unit 24.

  In the apparatus main body 21, toner containers 99Y, 99M, 99C, and 99K, an intermediate transfer unit 92, an image forming unit 93, an exposure unit 94, and a paper feed cassette 211 are accommodated in this order from the top.

  The image forming unit 93 forms an image on a sheet based on the image data output from the image reading device 22. The image forming unit 93 forms four image forming units 10Y and 10M that form yellow (Y), magenta (M), cyan (C), and black (Bk) toner images in order to form a full-color toner image. 10C, 10Bk. Each of the image forming units 10Y, 10M, 10C, and 10Bk includes a photosensitive drum 11 and a charger 12, a developing device 13, a primary transfer roller 14, and a cleaning device 15 that are disposed around the photosensitive drum 11. .

  The photosensitive drum 11 rotates about its axis, and an electrostatic latent image and a toner image are formed on its peripheral surface. As the photoreceptor drum 11, a photoreceptor drum using an amorphous silicon (a-Si) material can be used. The charger 12 uniformly charges the surface of the photosensitive drum 11. The peripheral surface of the photosensitive drum 11 after charging is exposed by the exposure unit 94 to form an electrostatic latent image.

  The developing device 13 supplies toner to the peripheral surface of the photosensitive drum 11 in order to develop the electrostatic latent image formed on the photosensitive drum 11. The developing device 13 is for a two-component developer and includes stirring rollers 16 and 17, a magnetic roller 18, and a developing roller 19. The stirring rollers 16 and 17 charge the toner by circulating and conveying the two-component developer while stirring. A two-component developer layer is carried on the peripheral surface of the magnetic roller 18, and toner formed by transferring toner to the peripheral surface of the developing roller 19 due to a potential difference between the magnetic roller 18 and the developing roller 19. The layer is supported. The toner on the developing roller 19 is supplied to the peripheral surface of the photosensitive drum 11 and the electrostatic latent image is developed.

  The primary transfer roller 14 forms a nip portion with the photosensitive drum 11 across the intermediate transfer belt 921 provided in the intermediate transfer unit 92, and the toner image on the photosensitive drum 11 is primary transferred onto the intermediate transfer belt 921. To do. The cleaning device 15 cleans the peripheral surface of the photosensitive drum 11 after the toner image is transferred.

  The yellow toner container 99Y, the magenta toner container 99M, the cyan toner container 99C, and the black toner container 99Bk each store toner of each color, and image forming units 10Y, 10M, and 10C corresponding to the respective colors of YMCBk. Each color toner is supplied to the 10 Bk developing device 13 through a supply path (not shown).

  The exposure unit 94 includes various optical system devices such as a light source, a polygon mirror, a reflection mirror, and a deflection mirror, and is provided on the peripheral surface of the photosensitive drum 11 provided in each of the image forming units 10Y, 10M, 10C, and 10Bk. The electrostatic latent image is formed by irradiating light based on the image data of the document image.

  The intermediate transfer unit 92 includes an intermediate transfer belt 921, a driving roller 922, and a driven roller 923. On the intermediate transfer belt 921, toner images are overcoated from the plurality of photosensitive drums 11 (primary transfer). The overcoated toner image is secondarily transferred to the sheet supplied from the paper feed cassette 211 or the paper feed tray 30 by the secondary transfer unit 98. A driving roller 922 and a driven roller 923 that rotate the intermediate transfer belt 921 are rotatably supported by the apparatus main body 21.

  The paper feed cassette 211 stores a sheet bundle in which a plurality of sheets are stacked. A pickup roller 212 is disposed at the upper right side of the paper feed cassette 211. By driving the pickup roller 212, the uppermost sheet of the sheet bundle in the sheet feeding cassette 211 is fed out one by one and carried into the carry-in conveyance path 26. Note that a paper feed unit 40 including a paper feed tray 30 for manual paper feed is provided on the right side surface of the apparatus main body 21. The sheet placed on the paper feed tray 30 is carried into the carry-in conveyance path 26 by driving the paper feed roller 41 of the paper feed unit 40.

  On the downstream side of the carry-in conveyance path 26, a sheet conveyance path 28 that extends to the discharge port 961 through the secondary transfer unit 98, a fixing unit 97 and a paper discharge unit 96 described later is provided. The upstream portion of the sheet conveyance path 28 is formed between an inner wall formed in the apparatus main body 21 and an inner wall that forms the inner surface of the reverse conveyance unit 29. The outer surface of the reverse conveyance unit 29 constitutes one side of a reverse conveyance path 291 that reversely conveys the sheet during duplex printing. A registration roller pair 27 is disposed on the upstream side of the sheet transfer path 28 from the secondary transfer unit 98. After the sheet is temporarily stopped by the registration roller pair 27 and skew correction is performed, the sheet is sent to the secondary transfer unit 98 at a predetermined timing for image transfer.

  A fixing unit 97 and a paper discharge unit 96 are accommodated in the connection housing 23. The fixing unit 97 includes a fixing roller and a pressure roller, and performs a fixing process by heating and pressing the sheet on which the toner image is secondarily transferred in the secondary transfer unit 98. The sheet with the color image that has been subjected to the fixing process is discharged from the discharge port 961 toward the in-body discharge unit 24 by the discharge unit 96 disposed downstream of the fixing unit 97.

  The image reading device 22 includes a first contact glass 222 and a second contact glass 223 that are fitted into the upper surface 221 of the upper casing. The first contact glass 222 is provided for reading a document sheet automatically fed from the ADF when an automatic document feeder (ADF; not shown) is arranged on the image reading device 22. The second contact glass 223 is provided for reading a manually placed document sheet.

  The image reading device 22 includes a first moving carriage 224, a second moving carriage 225, a condenser lens unit 228, and an image sensor 229 (light receiving device) housed in the upper housing. The first moving carriage 224 is mounted with the illumination device 50 according to the embodiment of the present invention and the first reflection mirror 226. A second reflecting mirror 227A and a third reflecting mirror 227B are mounted on the second moving carriage 225 in order to reverse the optical path.

  The first moving carriage 224 reciprocates in the left-right direction along the lower surfaces of the first contact glass 222 and the second contact glass 223. The second moving carriage 225 reciprocates in the left-right direction with a movement amount ½ that of the first moving carriage 224. The first moving carriage 224 moves immediately below the first contact glass 222 and becomes stationary when in an automatic feeding mode in which the document sheet is automatically fed from an unillustrated automatic document feeder. In this stationary state, light is emitted from the illumination device 50 toward the document sheet. On the other hand, in the manual placement mode in which the document sheet is placed on the second contact glass 223, the first moving carriage 224 moves to the right according to the size of the document sheet from directly below the left end of the second contact glass 223. . During this movement, light is emitted from the illumination device 50 toward the document sheet. The second moving carriage 225 moves to the right following the first moving carriage 224 with a movement amount ½ of the first moving carriage 224.

  The illuminating device 50 irradiates a document sheet as an irradiation object with linear illumination light that is long in the main scanning direction. Specifically, the illuminating device 50 directs an original sheet image toward an automatically fed original sheet passing over the first contact glass 222 or a manually placed original sheet placed on the second contact glass 223. Illumination light is emitted for optical reading. The first reflection mirror 226 reflects the reflected light of the illumination light emitted from the illumination device 50 toward the document sheet so as to be directed toward the second reflection mirror 227A of the second movable carriage 225.

  The second reflecting mirror 227A reflects the reflected light reflected by the first reflecting mirror 226 toward the third reflecting mirror 227B. The third reflection mirror 227 </ b> B reflects the reflected light toward the condenser lens unit 228. The condenser lens unit 228 forms an optical image of the reflected light reflected by the third reflecting mirror 227B on the imaging surface of the imaging element 229. The image sensor 229 is composed of a CCD (charge coupled device) or the like, and receives reflected light and photoelectrically converts it into an analog electric signal. This analog electrical signal is converted into a digital electrical signal by an A / D conversion circuit (not shown), and then input to the exposure unit 94 as image data.

  A white reference plate (not shown) for determining a white reference for reading density is disposed on the left end side of the second contact glass 223. Before the image reading operation, the white reference plate is irradiated with illumination light, and the reflected light is received by the image sensor 229, and a correction value is obtained in advance so that the image data at this time becomes a uniform output in the main scanning direction. (Shading correction).

  Then, the detail of the illuminating device 50 which concerns on this embodiment is demonstrated. 2 and 3 are perspective views of the illumination device 50 on the first moving carriage 224. FIG. 4 is a perspective view of the first light guide 52A of the lighting device 50, and FIG. 5 is a cross-sectional view of the first light guide 52A. Further, FIG. 6 is a schematic cross-sectional view showing the arrangement of the respective light guides of the illumination device 50. 7 and 8 are exploded perspective views of the lighting device 50. FIG.

  The illumination device 50 irradiates light with the original sheet (object to be irradiated) arranged on the first contact glass 222 or the second contact glass 223 (predetermined arrangement surface) as a focal position. The illumination device 50 is disposed on the first moving carriage 224 along the main scanning direction (first direction, arrow D1 in FIGS. 2 and 3).

  The illumination device 50 includes a light source 51 (see FIG. 8) and a light guide 52. The light guide 52 propagates the illumination light emitted from the light source 51, converts the illumination light into a linear illumination light, and emits it. The light source 51 includes a first light source 51A and a second light source 52B. The light guide 52 includes a first light guide 52A and a second light guide 52B.

  The first light guide 52A has a rod-like shape that is long in the first direction. The first light guide 52A includes a first incident surface 54A and a first emission surface 56A (FIG. 4). 54 A of 1st incident surfaces are arrange | positioned at the edge part of the 1st direction of 52 A of 1st light guides, and light injects into 54 A of 1st incident surfaces along a 1st direction. In the present embodiment, a pair of first incident surfaces 54A are disposed at both ends in the first direction of the first light guide 52A. The first emission surface 56A emits the light in a second direction (arrow D2 in FIGS. 4 and 6) that extends along the first direction and intersects the first direction. The first light guide 52A irradiates the original sheet with light from the second direction.

  The second light guide 52B has a rod-like shape that is spaced from the first light guide 52A and is long in the first direction. The second light guide 52B includes a second incident surface 54B and a second emission surface 56B. The second incident surface 54B is disposed at the end of the second light guide 52B in the first direction, and light is incident on the second incident surface 54B along the first direction. In the present embodiment, a pair of second incident surfaces 54B are disposed at both ends in the first direction of the second light guide 52B. The second emission surface 56B extends along the first direction, and emits the light in a third direction (arrow D3 in FIGS. 4 and 6) described later that intersects the first direction and the second direction. Then, the second light guide 52B irradiates the original sheet with light from the third direction.

  The light source 51 (first light source 51A, second light source 52B) has a thin disk shape and includes a white LED (Light Emitting Diode) 51L that emits white light. As the white LED 51L, for example, a high-brightness LED package in which a GaN-based or InGaN-based semiconductor light emitting element that emits blue light or ultraviolet light is sealed with a transparent resin containing a phosphor can be used.

  In the present embodiment, the first light source 51A and the second light source 51B are disposed in pairs at both ends of the first light guide 52A and the second light guide 52B, respectively. In other words, the pair of first light sources 51A is disposed to face the pair of first incident surfaces 54A of the first light guide 52A, and emits illumination light incident on the first incident surfaces 54A. In addition, the pair of second light sources 51B is disposed to face the pair of second incident surfaces 54B of the second light guide 52B, and emits illumination light incident on the second incident surfaces 54B.

  Next, the structure of the first light guide 52A and the second light guide 52B will be further described with reference to FIGS. In the present embodiment, the second light guide 52B has the same configuration as the first light guide 52A, and the first light guide 52A and the second light guide 52B are different from each other in the illumination device 50. . Therefore, in FIGS. 4 and 5, the structure of the first light guide 52A will be mainly described as an example. 4 and 5, the reference numerals of the elements of the second light guide 52 </ b> B corresponding to the elements of the first light guide 52 </ b> A are shown in parentheses.

  The first light guide 52A is formed of a translucent resin material such as acrylic resin, has a long bar shape in the main scanning direction (first direction), and emits illumination light emitted from the first light source 51A. It includes a main body 53 that guides light and a pair of first incident surfaces 54A that are both end surfaces of the main body 53 in the first direction and on which the illumination light is incident. The light emitting surfaces of the pair of first light sources 51A are disposed to face the pair of first incident surfaces 54A, respectively. In FIG. 4, the first light source 51A on the front end side in the first direction is not shown.

  The first light guide 52A is further provided with a first emission surface 56A disposed on the upper surface side of the main body 53 (the side facing the first and second contact glasses 222, 223), and the first emission surface 56A. And a first reflecting surface 57 </ b> A disposed on the lower surface side of the main body 53. The first emission surface 56A extends along the main scanning direction (first direction) on the upper surface of the main body 53, and has a predetermined width in the direction orthogonal to the main scanning direction, and the first and second illumination lights 2 A surface that emits light toward the contact glass 222, 223 (original sheet). The direction in which the illumination light is emitted from the first emission surface 56A is defined as the second direction (arrow D2 in FIGS. 4 and 5). Similarly, the first reflecting surface 57A is a belt-like surface extending in the main scanning direction, and reflects the illumination light propagating through the main body 53 toward the first emitting surface 56A. 56 A of 1st output surfaces have a comparatively loose convex curved surface in the direction which cross | intersects the main scanning direction. On the other hand, the first reflecting surface 57A is a flat surface. A number of minute prisms (not shown) are provided on the first reflecting surface 57A. The prism reflects light toward the first emission surface 56A.

  As described above, the second light guide 52B also has the same structure as the first light guide 52A. That is, the second light guide 52B also includes a main body 53, and the first light entrance surface 54A, the first light exit surface 56A, and the first reflection surface 57A of the first light guide 52A are respectively the same as those of the second light guide 52B. This corresponds to the second entrance surface 54B, the second exit surface 56B, and the second reflection surface 57B. The direction in which the illumination light is emitted from the second emission surface 56B is defined as the third direction (arrow D3 in FIGS. 4 and 5). In this way, the first light guide 52A and the second light guide 52B have the same shape and structure. For this reason, sharing of two light guides is suitably realized.

  Furthermore, the illuminating device 50 is provided with the 1st support part 80, the 2nd support part 81, and the LED support part 82 (FIG. 2). The first support portion 80 and the second support portion 81 are plate-like members that are erected upward from the first moving carriage 224. The first support portion 80 supports the first light guide 52A and the second light guide 52B on one end side in the first direction. The LED support portion 82 is disposed to face the first support portion 80, and supports the first light source 51A and the second light source 51B. The second support portion 81 supports the first light guide 52A and the second light guide 52B on the other end side in the first direction. Further, the second support portion 81 supports the other first light source 51A and second light source 51B inside. The first support portion 80 and the LED support portion 82 will be described in further detail later.

  Next, the direction of irradiation light in the present embodiment will be described with reference to FIG. The first light guide 52A and the second light guide 52B are arranged so as to be inclined at a predetermined angle so that their emission surfaces face each other. As described above, the first light guide 52A irradiates the original sheet P with the light from the first light source 51A from the second direction. The second light guide 52B irradiates the original sheet P with light from the second light source 51B from the third direction. That is, in the cross-sectional view intersecting with the first direction shown in FIG. 6, the second direction is one of the normal lines RL perpendicular to the first contact glass 222 or the second contact glass 223 (arrangement surface). This is a direction from the arrangement surface side toward the document sheet P. The third direction is a direction from the other arrangement surface side toward the original sheet P with respect to the normal line RL. Therefore, it is possible to stably irradiate the original sheet P from both sides of the normal line RL. Furthermore, in the present embodiment, the triangle TR connecting the first light guide 52A, the second light guide 52B, and the focal point SP of the irradiation light is an isosceles triangle in the cross-sectional view. For this reason, the distribution of light applied to the document sheet P from the first light guide 52A and the second light guide 52B is axisymmetric in a cross-sectional view intersecting the first direction. For this reason, even if the light emitted from the first light guide 52A and the second light guide 52B overlaps, the original sheet P can be irradiated with uniform light. In other words, the amount of light on the side of one original sheet P is suppressed from becoming smaller than the amount of light on the side of the other original sheet P with the normal RL as a boundary. In another embodiment, the triangle TR connecting the first light guide 52A, the second light guide 52B, and the focal point SP of the irradiation light may be an equilateral triangle.

  In the above configuration, the first direction is the main scanning direction of the image reading device 22, and the direction from the first light guide 52A toward the second light guide 52B in a cross-sectional view intersecting the first direction (FIG. 6). Arrow D4) is the sub-scanning direction. The original sheet P that is an object to be irradiated is irradiated with light from the two light guides (first light guide 52A and second light guide 52B). In addition, two light sources (first light source 51A and second light source 51B) are arranged in each of the two light guides. For this reason, compared with the case where light is irradiated from one light guide, it is possible to irradiate the original sheet P with a larger amount of light. In addition, since the amount of light emitted from one light source can be small, the amount of heat generated by each light source can be reduced. Therefore, the first light guide 52A, the light guide 52, and surrounding members are preferably prevented from being thermally deformed by the heat.

  Next, a mechanism for adjusting the distance between the incident surface 54 and the light source 51 in the illumination device 50 will be described with reference to FIGS. 7 and 8 are exploded perspective views of one end side of the lighting device 50 in the first direction as seen from different directions. FIG. 9 is a cross-sectional view of the one end side of the lighting device 50 as viewed from above.

  The illumination device 50 includes a distance restriction unit 8. The distance regulating unit 8 can adjust the distance between the light source 51 (the first light source 51A and the second light source 51B) and the incident surface 54 (the first incident surface 54A and the second incident surface 54B) and guides the light. The incident surface 54 is prevented from coming into contact with the light guide 52 due to thermal expansion of the body 52 (first light guide 52A, second light guide 52B) in the first direction (arrow D1 in FIG. 9). .

  As described above, the first support portion 80 supports one end portion of the light guide 52 in the first direction. The first support portion 80 includes a first opening 801A and a second opening 801B (both are openings). With reference to FIGS. 7 and 9, the first opening 801 </ b> A and the second opening 801 </ b> B are openings that are opened in a circular shape in the first support portion 80. One end sides of the first light guide 52A and the second light guide 52B in the first direction are inserted through the first opening 801A and the second opening 801B, respectively. As a result, as shown in FIG. 7, the first incident surface 54A and the second incident surface 54B of the first light guide 52A and the second light guide 52B are outside the first opening 801A and the second opening 801B. It is exposed to the light source 51 side. Further, the first support portion 80 includes a pair of nut fixing portions 802S. The nut fixing portion 802S is disposed outside the first opening 801A and the second opening 801B. A fastening nut 802 is attached to the nut fixing portion 802S. The nut fixing portion 802S has a regular hexagonal shape in a cross-sectional view, and the rotation of the attached fastening nut 802 is restricted.

  On the other hand, as described above, the second support portion 81 supports the other end side (the opposite side to the one end side) of the first light guide 52A and the second light guide 52B in the first direction. Specifically, the second support portion 81 includes a spacer member similar to the spacer 86 described later, and the other end sides of the first light guide 52A and the second light guide 52B are in contact with the spacer member. For this reason, the other end sides of the first light guide 52A and the second light guide 52B are fixed in the first direction by the second support portion 81.

  In addition, the LED support portion 82 (light source support portion) is disposed at an interval in the first direction with respect to the first support portion 80 and supports the light source 51 so as to face the incident surface 54. As shown in FIG. 9, the first light source 51 </ b> A and the second light source 51 </ b> B are arranged at an interval in a direction orthogonal to the first direction. The LED support portion 82 includes a screw through hole 821 (screw opening). The screw through holes 821 are a pair of holes that are opened through the plate-like LED support portion 82. A screw 83 described later is inserted through the screw through hole 821. The inner diameter of the screw through hole 821 is set larger than the outer diameter of the screw 83.

  In the present embodiment, the distance between the light source 51 and the incident surface 54 is adjusted by adjusting the distance in the first direction between the first support part 80 and the LED support part 82. The distance regulating unit 8 includes a screw 83, a position adjusting nut 84 (positioning nut), a biasing spring 85, and a spacer 86.

  The screw 83 passes through the LED support portion 82 and is fastened to the first support portion 80. A pair of screws 83 are arranged corresponding to the pair of screw through holes 821 described above. The screw 83 includes a screw head 83S (screw head). The screw head 83 </ b> S is disposed on the opposite side of the LED support portion 82 from the first support portion 80. The screw 83 is inserted into the screw through hole 821 and fastened to the fastening nut 802.

  A pair of position adjustment nuts 84 are rotatably mounted on the pair of screws 83 between the LED support portion 82 and the first support portion 80. In the present embodiment, the position adjustment nut 84 includes two nuts. Of the two nuts, the nut on the LED support portion 82 side defines the position of the LED support portion 82. Further, the nut on the first support portion 80 side has a function of preventing rotation of the nut on the LED support portion 82 side.

  The biasing spring 85 is inserted through the screw 83 and is disposed between the screw head 83 </ b> S of the screw 83 and the LED support portion 82. The urging spring 85 urges the LED support portion 82 toward the first support portion 80. A pair of urging springs 85 are arranged corresponding to the pair of screws 83.

  The spacer 86 is disposed between the incident surface 54 (first incident surface 54A, second incident surface 54B) and the light source 51 (first light source 51A, second light source 51B). The spacer 86 is fixed to the first support portion 80 side of the LED support portion 82. The spacer 86 is a plate-like member disposed so as to surround the pair of light sources 51. The spacer 86 includes a hole 861 and a contacted portion 862. The hole portion 861 is a hole through which illumination light emitted from the light source 51 passes. For this reason, the inner diameter of the hole 861 is set corresponding to the area of the light emitting part of the light source 51. The contacted portion 862 is disposed so as to surround the hole portion 861. The contacted portion 862 is a wall surface of the spacer 86 facing the first support portion 80 side. The inner diameter of the hole 861 is set smaller than the outer diameters of the first incident surface 54A and the second incident surface 54B. In other words, in the first direction, the abutted portion 862 faces the outer edge portions of the first incident surface 54A and the second incident surface 54B.

  Next, the function of the distance regulating unit 8 according to this embodiment will be described. As described above, at the other end side of the light guide 52 in the first direction, the end of the light guide 52 is in contact with a spacer member (not shown). That is, the other end of the light guide 52 is in contact with the spacer member. On one end side of the light guide 52, as shown in FIG. 7, the first incident surface 54A and the second incident surface 54B are exposed from the first opening 801A and the second opening 801B, respectively. Further, a fastening nut 802 is attached to each of the pair of fastening nuts 802S. In this state, the LED support portion 82 on which the screw 83, the position adjustment nut 84 and the biasing spring 85 are mounted in advance is attached to the first support portion 80. At this time, the pair of attachment projections 803 protruding from the first support portion 80 toward the LED support portion 82 is inserted into the pair of attachment holes 822 opened in the LED support portion 82. The pair of screws 83 are fastened to the pair of fastening nuts 802 so that the first support portion 80 and the LED support portion 82 are integrally fixed. At this time, the LED support portion 82 is brought into contact with the position adjustment nut 84 on the LED support portion 82 side by the biasing force of the biasing spring 85.

  With reference to FIG. 9, in this embodiment, the thickness of the spacer 86 between the light source 51 and the incident surface 54 is set to 0.25 mm. Then, at the stage of assembling the lighting device 50, the initial position adjustment nut 84 is set so that the contact portion 52 </ b> F protruding in the radial direction from the end of the light guide 52 contacts the contacted portion 862 of the spacer 86. The position is set. And the light quantity of the illumination light radiate | emitted from the output surface 56 (1st output surface 56A, 2nd output surface 56B) is measured by the light quantity measurement apparatus not shown so that this light quantity may become the preset target value. The position adjusting nut 84 is moved in the direction of the rotation axis of the screw 83. Specifically, the position adjustment nut 84 is rotated so as to be separated from the first support portion 80. Then, the position adjustment nut 84 moves the LED support portion 82 toward the screw head 83 </ b> S against the biasing force of the biasing spring 85. As a result, the spacer 86 is moved away from the incident surface 54 in the first direction, and the distance between the light source 51 and the incident surface 54 is changed. In the present embodiment, the distance between the light source 51 and the incident surface 54 can be adjusted from 0.25 mm to 0.75 mm. The design reference value for the distance is 0.50 mm. Then, by adjusting the positions of the position adjusting nuts 84 on the first light guide 52A side and the second light guide 52B side, the original sheet P is transferred from the first light guide 52A and the second light guide 52B. The uniformity of the irradiation light irradiated in the first direction (main scanning direction) is adjusted. As described above, in the present embodiment, the distance between the light source 51 and the incident surface 54 of the light guide 52 is adjusted according to the variation in the light emission amount of the light source 51, and the amount of light applied to the document sheet is adjusted. Is possible. Further, the distance between the light source 51 and the incident surface 54 is adjusted by adjusting the distance between the first support portion 80 and the LED support portion 82. For this reason, compared with the case where the light source 51 and the light guide 52 are moved directly, the distance between the light source 51 and the entrance plane 54 is set stably. Further, the distance can be easily adjusted by the rotational movement of the position adjusting nut 84.

  As described above, the lighting device 50 is used in a state where a slight gap is formed between the spacer 86 and the incident surface 54. When the printing operation is continuously performed in the image forming apparatus 1, the light guide 52 is likely to be thermally expanded by the heat generated from the light source 51. Even in such a case, in this embodiment, when the light guide 52 is thermally expanded in the first direction, the incident surface 54 presses the contacted portion 862 of the spacer 86 in the direction of the arrow D1 in FIG. As a result, the LED support portion 82 is pressed by the light guide 52, and the LED support portion 82 is moved away from the first support portion 80 against the biasing force of the biasing spring 85. At this time, a slight gap is formed between the LED support portion 82 and the position adjustment nut 84. As a result, even when the light guide 52 is thermally expanded in the first direction as the light source 51 generates heat, the thermal expansion is favorably absorbed, and the incident surface 54 does not contact the light source 51. The light source 51 is prevented from being deformed and damaged. Further, the distance between the light source 51 and the incident surface 54 is kept constant by the spacer 86. Further, even if the incident surface 54 strongly contacts the spacer 86, the movement of the LED support portion 82 prevents the spacer 86 or the light guide 52 from being damaged.

  Further, in the image reading apparatus 22 and the image forming apparatus 1 provided with the illumination device 50 according to the present embodiment, the original sheet is stably irradiated with light, and the image on the original sheet is suitably read by the image reading apparatus 22. Furthermore, an image is stably formed on the sheet based on the image data of the original sheet.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to this, For example, the following modified embodiment can be taken.

  In the above embodiment, a pair of the first incident surface 54A and the first light source 51A are disposed at both ends in the first direction of the first light guide 52A, and the second incident surface 54B and the second light source 51B are the second Although a pair of the light guides 52B is disposed at both ends in the first direction, the present invention is not limited to this. The first incident surface 54A and the first light source 51A are disposed on one end side in the first direction of the first light guide 52A, and the second incident surface 54B and the second light source 51B are the first of the second light guide 52B. The aspect arrange | positioned at the other end side opposite to the said one end side of a direction may be sufficient. Even in this case, it is possible to irradiate the original sheet P with a larger amount of light compared to the case where the original sheet P is irradiated with light from one light guide. In addition, the amount of heat generated by each light source can be reduced. In addition, since the first light source 51A and the second light source 51B are respectively arranged on the opposite sides in the first direction, the light quantity on the downstream side in the emission direction in which light is easily attenuated among the one light source is set to the emission direction of the other light source It can be compensated by the upstream light quantity. Accordingly, the original sheet P is irradiated with uniform light along the first direction. In the case of the above configuration, it is desirable that a reflection sheet is disposed on the surface of each light guide opposite to the incident surface. Moreover, the light guide 52 may be one.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 11 Photosensitive drum 22 Image reader 224 1st moving carriage 229 Image sensor (light receiving device)
50 Illumination Device 51 Light Source 51A First Light Source 51B Second Light Source 51L White LED
52 light guide 52A first light guide 52B second light guide 53 main body 54 entrance surface 54A first entrance surface 54B second entrance surface 56 exit surface 56A first exit surface 56B second exit surface 57 reflection surface 57A first 1 reflective surface 57B 2nd reflective surface 8 distance control part 80 1st support part 801A 1st opening part (opening part)
801B Second opening (opening)
802 Nut for fastening 81 Second support portion 82 LED support portion (light source support portion)
821 Screw through hole (screw opening)
83 screw 83S screw head (screw head)
84 Position adjustment nut (positioning nut)
85 Biasing spring 86 Spacer 861 Hole portion 862 Contacted portion 93 Image forming portion

Claims (9)

An illumination device for irradiating light on an object to be irradiated arranged on a predetermined arrangement surface,
It has a rod-like shape that is long in the first direction, is disposed at one end of the first direction, and has an incident surface on which light is incident along the first direction, and extends along the first direction. A light guide that emits light to the object to be irradiated, and an emission surface that emits the light in a direction intersecting the direction;
A light source arranged to face the incident surface of the light guide and emitting illumination light incident on the incident surface;
A distance regulating unit that enables adjustment of a distance between the light source and the incident surface and prevents the incident surface from coming into contact with the light source due to thermal expansion of the light guide in the first direction; ,
A lighting device comprising: A first support portion that includes an opening portion through which the one end portion of the light guide is inserted, exposes the incident surface outside the opening portion, and supports the one end portion;
A second support portion for fixing the other end portion of the light guide opposite to the one end portion in the first direction;
A light source support that is disposed at a distance in the first direction with respect to the first support and supports the light source so as to face the incident surface;
Further comprising
The lighting device according to claim 1, wherein a distance between the light source and the incident surface is adjusted by adjusting a distance between the first support part and the light source support part. . The distance regulating unit is
A screw that includes a screw head disposed on the side opposite to the first support part with respect to the light source support part, and penetrates the light source support part and is fastened to the first support part;
A screw opening that is opened in the light source support and through which the screw is inserted;
A positioning nut rotatably mounted on the screw between the light source support and the first support;
A biasing spring that is disposed between the screw head of the screw and the light source support, and biases the light source support toward the first support;
Have
The lighting device according to claim 2, wherein the distance between the light source and the incident surface is changed by moving the positioning nut in the direction of the rotation axis of the screw. The incident portion includes a hole portion that is fixed to the first support portion side of the light source support portion and through which the illumination light emitted from the light source passes, and a contacted portion that is disposed so as to surround the hole portion. Further comprising a spacer disposed between a surface and the light source;
When the light guide body is thermally expanded in the first direction and the incident surface presses the contacted portion of the spacer, the light source support portion resists the biasing force of the biasing spring. The lighting device according to claim 3, wherein the lighting device is moved in a direction away from the unit. The light guide is
It has a rod-like shape that is long in the first direction, and is disposed at one end of the first direction, and has a first incident surface on which light is incident along the first direction, and extends along the first direction. A first light guide that emits light from the second direction to the object to be irradiated; and a first light-emitting surface that emits the light in a second direction that intersects the first direction;
A second incident surface having a rod-like shape long in the first direction, disposed adjacent to the first incident surface at the one end portion in the first direction, and receiving light along the first direction; A second emission surface that extends along the first direction and emits the light in a third direction that intersects the first direction and the second direction, and emits light from the third direction to the object to be irradiated. A second light guide that irradiates
The light source is
A first light source that is disposed to face the first incident surface of the first light guide and emits illumination light incident on the first incident surface;
5. A second light source that is disposed to face the second incident surface of the second light guide and emits illumination light that is incident on the second incident surface. 6. The lighting device according to any one of the above. In a cross-sectional view intersecting the first direction,
The second direction is a direction from the one placement surface side toward the irradiated object with respect to a normal line orthogonal to the placement surface,
The lighting device according to claim 5, wherein the third direction is a direction from the other arrangement surface side toward the irradiated object with respect to the normal line. The irradiated object is disposed at a focal position of light emitted from the first light guide and the second light guide,
The triangle connecting the first light guide, the second light guide, and the focal point in the cross-sectional view is an equilateral triangle or an isosceles triangle having the focal point as an apex. The lighting device described. The illumination device according to any one of claims 1 to 7, which irradiates illumination light onto a document sheet as the irradiation object;
An image reading apparatus comprising: a light receiving device that receives reflected light from the original sheet and converts the light into an electric signal. An image reading apparatus according to claim 8,
An image forming unit that forms an image on a sheet based on image data output from the image reading device;
An image forming apparatus comprising:

Images