JP6256307B2 - Lighting device - Google Patents

Description

  The present invention relates to an illumination device using a light guide that guides illumination light emitted from a light source.

  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.

  A lighting device using a high-intensity LED and a light guide described in Patent Document 1 or the like usually includes a heat radiating plate (heat sink) because a large amount of heat is emitted from the LED. By generating heat from the heat radiating plate, the heat of the LED substrate and the LED itself is lowered to prevent the life of the substrate and the LED deterioration.

JP 2008-216409 A

  By the way, in the illuminating device described in patent document 1 etc., when a larger irradiation light quantity is required, when the light emission amount of LED increased, the light guide body might thermally expand. In order to suppress the thermal expansion of the light guide, it is necessary to sufficiently dissipate the heat, and for this purpose, the heat sink must be enlarged. However, since an increase in the size of the heat sink leads to an increase in the size of the lighting device itself, it is desirable to avoid an increase in the size of the heat sink as much as possible.

  This invention is made | formed in view of said situation, and provides the illuminating device which can be thermally radiated efficiently, without enlarging a heat sink, corresponding to the thermal expansion of a light guide. Objective.

In order to achieve the above object, the present invention is an illuminating device for irradiating an object to be irradiated arranged on a predetermined arrangement surface, having a rod-like shape long in a first direction, and having one end in the first direction. An incident surface on which light is incident along the first direction, and an exit surface that extends along the first direction and emits the light in a direction intersecting the first direction. A light guide that irradiates light to the object to be irradiated, a light source that is disposed to face the incident surface of the light guide and emits illumination light incident on the incident surface, and heat from the light source. A heat radiating plate for radiating heat, a frame for supporting the heat radiating plate, a heat conducting member interposed between the heat radiating plate and the frame, and transferring heat of the heat radiating plate to the frame; Move the heat sink in a direction away from the light guide with thermal expansion in one direction Comprising a moving mechanism for the, the heat conducting member is a sheet shape, or the heat conducting member comprises illumination device that have a concavo-convex shape.

  ADVANTAGE OF THE INVENTION According to this invention, it can thermally radiate efficiently, without enlarging a heat sink, corresponding to the thermal expansion of a light guide.

It is sectional drawing which shows the image forming apparatus provided with 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 light guide concerning one embodiment of the present invention. It is sectional drawing of the light guide 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 cross-sectional view showing an internal structure of an image forming apparatus 1 including an illumination device 50 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 99Bk, 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 10 </ b> Y, 10 </ b> M, 10 </ b> C, and 10 </ b> Bk includes a photosensitive drum 11, a charger 12 disposed around the photosensitive drum 11, a developing device 13, a primary transfer roller 14, and a cleaning device 15.

  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. FIG. 2 is a perspective view of the lighting device 50. 3 is a perspective view of the first light guide 52A of the lighting device 50, and FIG. 4 is a cross-sectional view of the first light guide 52A. FIG. 5 is a perspective view showing one end side (moving mechanism side) of the illumination device 50. FIG. 6 is a cross-sectional view schematically showing one end side (moving mechanism side) of the illumination device 50.

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 includes a light source 51 (see FIG. 6) 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 guide 52 includes a first light guide 52A and a second light guide 52B.
As shown in FIG. 2, the first light guide 52A has a rod-like shape that is long in the first direction (main scanning direction, arrow D1 in FIG. 2). The first light guide 52A includes a first incident surface 54A and a first emission surface 56A. 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. 3 and 4) 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. 3 and 4) intersecting 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 includes a first light source 51A and a second light source 51B.
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.

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

  Next, the structures 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. . Here, the structure of the first light guide 52A will be mainly described as an example. In FIGS. 3 and 4, reference numerals of the elements corresponding to the elements of the second light guide 52B and corresponding to the elements of the first light guide 52A are shown in parentheses.

  The first light guide 52A is formed of a translucent resin material such as acrylic resin, has a long rod shape in the first direction (main scanning 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.

  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 first direction (main scanning direction) on the upper surface of the main body 53, and has a predetermined width in a 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. 3 and 4). 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. 3 and 4). 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.

Further, the lighting device 50 includes a first support portion 80, a second support portion 81, a mounting substrate (LED substrate) 82, a third support portion 90, a fourth support portion 91, a heat sink 100, a frame 230, and a slider 231. .
The first support portion 80 is a plate-like member that is erected upward from a frame 230 that is a separate member from the first moving carriage 224. The second support portion 81 is a plate-like member that is 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 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 third support part 90 fixedly supports the light guide 52 (first light guide 52A and second light guide 52B) having a rod shape long in the first direction on the first moving carriage 224. The fourth support portion 91 fixedly supports the third support portion 90 on the first moving carriage 224.

The mounting substrate (LED substrate) 82 and the heat dissipation plate 100 are disposed on one end side and the other end side of the light guide 52 in the first direction, respectively. Here, the one end side (moving mechanism part 8 side) of the light guide 52 in the first direction will be described.
The mounting substrate (LED substrate) 82 is a plate-like member, and one surface is disposed to face the first support portion 80, and mounts (supports) the first light source 51A and the second light source 51B, and the other surface is The heat sink 100 is disposed to face the heat sink 100.
As shown in FIG. 6, the light source 51 is mounted on the mounting substrate 82 with a slight gap formed from the incident surface 54 of the light guide 52. In the present embodiment, the distance of the gap between the light source 51 and the incident surface 54 can be adjusted from 0.25 mm to 0.75 mm, and the design reference value is 0.50 mm.

  The heat radiating plate 100 is a plate-like member disposed to face the mounting substrate 82. The heat sink 100 is usually designed to be thicker than the mounting board 82 in order to dissipate heat from the light source 51. The heat sink 100 is made of a metal having high thermal conductivity such as aluminum.

  The frame 230 is formed of a member different from the first moving carriage 224, and fixes and supports the heat sink 100 (right side in FIG. 2), and is positioned below the heat sink 100. The frame 230 is fixed by a slider 231 so as to be relatively movable in the X direction (left-right direction) in FIG.

  Referring to FIG. 6, heat conductive member 110 is interposed between bottom portion 100 a of heat radiating plate 100 and corner portion 230 a of frame 230, and heat of heat radiating plate 100 is radiated to external frame 230. The heat conducting member 110 is desirably a sheet-like material with good sliding properties, and examples thereof include a rubber sheet.

  The shape of the heat conducting member 110 at the contact surface between the bottom portion 100a of the heat sink 100 and the corner portion 230a of the frame 230 is not particularly limited, and examples thereof include a planar shape and an uneven shape. From the viewpoint of increasing the effect, the uneven shape is desirable.

  In the present embodiment, the light source 51 is mounted on the mounting board 82, and the mounting board 82 is in contact with the heat sink 100. The heat radiating plate 100 is in contact with the frame 230 via the heat conducting member 110. Thereby, heat from the light source 51 is radiated to the frame 230.

  Next, with reference to FIG.5 and FIG.6, the moving mechanism part 8 in the illuminating device 50 is demonstrated. In FIG. 6, the structure of the first light guide 52A will be mainly described as an example. In FIG. 6, the reference numerals of the elements corresponding to the elements of the second light guide 52B and corresponding to the elements of the first light guide 52A are shown in parentheses.

  The moving mechanism unit 8 includes a screw 83, a position adjusting nut 84 (positioning nut), an urging spring 85, and a spacer 86.

  The screw 83 passes through the mounting substrate 82 and the spacer 86 and is fastened to the first support portion 80. A pair of screws 83 is disposed corresponding to the light guide 52 (first light guide 52A, second light guide 52B). The screw 83 includes a screw head 83S (screw head). The screw head 83 </ b> S is disposed on the opposite side of the mounting substrate 82 from the first support portion 80.

  A pair of position adjusting nuts 84 are rotatably mounted on the pair of screws 83 between the mounting substrate 82 and the spacer 86.

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

  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 mounting substrate 82. The spacer 86 is a plate-like member disposed so as to surround the pair of light sources 51. Although not shown, the spacer 86 includes a hole through which illumination light emitted from the light source 51 passes. For this reason, the inner diameter of the hole is set corresponding to the area of the light emitting part of the light source 51. The spacer 86 is provided with a contacted portion (not shown) so as to surround the hole. The abutted portion is a wall surface facing the first support portion 80 side of the spacer 86. The inner diameter of the hole 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 contacted portion faces the outer edge portions of the first incident surface 54A and the second incident surface 54B.

  The moving mechanism 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 source 51 due to thermal expansion in the first direction (arrow D1 in FIG. 2) of the body 52 (first light guide 52A, second light guide 52B).

  On the other hand, as shown in FIG. 2, 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.

  Referring to FIGS. 5 and 6, the mounting substrate 82 is disposed with a space 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. The first light source 51A and the second light source 51B are arranged at intervals in a direction orthogonal to the first direction. Although not shown, the mounting board 82 includes screw through holes (screw openings). The screw through holes are a pair of holes that are opened through the plate-shaped mounting substrate 82. A screw 83 is inserted through the screw through hole. The inner diameter of the screw through-hole is set larger than the outer diameter of the screw 83.

  Next, functions of the moving mechanism unit 8 according to the present 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 the spacer member. That is, the other end of the light guide 52 is in contact with the spacer member. In this state, the mounting board 82 on which the screw 83, the position adjusting nut 84 and the biasing spring 85 are mounted in advance is attached to the first support portion 80. At this time, the mounting board 82 is brought into contact with the position adjustment nut 84 on the mounting board 82 side by the biasing force of the biasing spring 85. In this embodiment, the light quantity of the illumination light emitted from the emission surface 56 (the first emission surface 56A and the second emission surface 56B) is measured by a light quantity measurement device (not shown), and the light quantity is set in advance as a target value. Thus, the position adjustment 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 adjusting nut 84 moves the mounting board 82 and the heat radiating plate 100 toward the screw head 83S against the urging force of the urging spring 85. As a result, the mounting substrate 82 and the heat radiating plate 100 are moved away from the incident surface 54 in the first direction, and the distance between the light source 51 and the incident surface 54 changes. 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. In addition, 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 mounting substrate 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 light source 51 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 first support portion 80 in the direction of the arrow D1 in FIG. As a result, the light guide 52 presses the mounting board 82 and the heat radiating plate 100 in contact with the mounting board 82, and the heat radiating plate 100 moves away from the first support portion 80 against the urging force of the urging spring 85. Move to. At this time, a slight gap is formed between the mounting substrate 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.

As described above, according to the present embodiment, even when the light guide 52 is thermally expanded in the first direction as the light source 51 generates heat, the heat sink 100 itself is separated from the thermally expanded light guide 52. Therefore, the incident surface 54 of the light guide 52 does not come into contact with the light source 51, and deformation and breakage of the light source 51 are prevented.
Further, since the heat from the heat sink 100 is radiated to the frame 230 via the heat conducting member 110, the heat dissipation effect is greater than when only the heat sink 100 is used. Therefore, heat can be radiated efficiently without increasing the size of the heat sink 100.

  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-described embodiment, the movement mechanism unit 8 has been described as being disposed only on one end side in the first direction of the light guide 52, but the present invention is not limited thereto, and the light guide is not limited thereto. The aspect arrange | positioned also at the other end side of the 1st direction of 52 may be sufficient.

  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 Although the embodiment has been described in which a pair is disposed at both ends of the second light guide 52B 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.

  The present invention is applicable to an illumination device using a light guide that guides illumination light emitted from a light source.

DESCRIPTION OF SYMBOLS 50 Illuminating device 51 Light source 52 Light guide 54 Injecting surface 56 Outgoing surface 82 Mounting substrate (LED substrate)
100 Heat sink (heat sink)
110 Thermal Conductive Member 230 Frame

Claims (3)

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;
A light source arranged to face the incident surface of the light guide and emitting illumination light incident on the incident surface;
A heat sink that dissipates heat from the light source;
A frame that supports the heat sink;
A heat conducting member interposed between the heat sink and the frame, and transferring heat of the heat sink to the frame;
A moving mechanism that moves the heat radiating plate in a direction away from the light guide along with the thermal expansion of the light guide in the first direction;
Equipped with a,
The heat conductive member, an illumination device, wherein a sheet-shape der Rukoto. 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;
A light source arranged to face the incident surface of the light guide and emitting illumination light incident on the incident surface;
A heat sink that dissipates heat from the light source;
A frame that supports the heat sink;
A heat conducting member interposed between the heat sink and the frame, and transferring heat of the heat sink to the frame;
A moving mechanism that moves the heat radiating plate in a direction away from the light guide along with the thermal expansion of the light guide in the first direction;
With
The heat conductive member, an illumination device according to claim Rukoto to have a concavo-convex shape. The lighting device according to claim 1 .
The illuminating device, wherein the heat conducting member has an uneven shape.

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