JP2009086593A - Illumination device, image reading device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively dissipate heat from a light source without arranging a retention member with complicated structure. <P>SOLUTION: An LED array 3 is fixed, without using an existing LED retention member, directly on a bent portion 5a integral with a first carriage 5 via adhesive or the like. The LED array 3 is mounted on the first carriage 5, which is made of thermally conductive sheet metal, so that heat generated by the emission of the LED array 3 is dissipated via the first carriage 5 quickly without keeping it in a board 2. The existing LED retention member is not required, thereby reducing the number of parts. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides an illuminating device including a scanning body in which a plurality of light emitting elements are arranged on a flat substrate, and a light source for illuminating an object to be illuminated such as an original with irradiation light from each light emitting element is mounted. The present invention also relates to an image reading apparatus and an image forming apparatus equipped with the illumination device.

  2. Description of the Related Art Conventionally, an image reading apparatus that reads document image information by irradiating light on a document has a configuration in which a xenon lamp is provided in the light source.

  In recent years, a configuration of a lighting device that employs a light emitting diode (LED) as an alternative light source of a xenon lamp has been put into practical use in response to demands for increasing the startup speed of the light source, saving energy, and extending the lifetime.

  However, since higher illuminance is required in response to the recent demand for productivity improvement (improvement of reading speed), it has become necessary to cope with an increase in the supply current to LEDs or an increase in the number of integrated LEDs. However, by implementing the above countermeasures, the amount of heat generated from the LEDs increases, and countermeasures against heat dissipation are an important solution as a countermeasure against failures caused by this.

Therefore, in the conventional illumination device, the light source holding member provided to fix and hold the light source on the scanning body is used as a heat conductive material, or fins, cooling holes and the like for increasing the cooling efficiency are provided in the light source holding member. A device has been devised (see Patent Documents 1 and 2).
Japanese Utility Model Publication No. 4-135349 Japanese Patent No. 3336069

  However, mounting a light source holding member having a complicated shape is undesirable because it leads to a complicated structure and an increase in cost.

  Therefore, an object of the present invention is to provide an illuminating device, an image reading device, and an image forming device that can effectively radiate a light source without providing a holding member having a complicated structure.

  In order to achieve the above object, the invention according to claim 1 includes a light source in which a plurality of light emitting elements are arranged in a plate-like substrate, and illuminates an object to be illuminated with light emitted from each light emitting element; The flat substrate in which the light emitting elements are arranged in an illuminating device including the light source and a mirror that receives reflected light from the illuminated body and deflects the light source in a predetermined direction, and a scanning body on which the light source is mounted. Is directly installed on the scanning body. With this configuration, a flat substrate on which a plurality of light emitting elements are arranged is directly attached to the traveling body, so that the light emitting elements emit light. The heat generated by the light can be quickly released to the scanning body without causing the substrate to burn, so that it is possible to prevent the occurrence of optical problems in illumination caused by the heat generation of the light emitting element. Scanning body through light source holding member Compared to the structure provided, it is possible to reduce the number of parts.

  According to a second aspect of the present invention, in the illumination device according to the first aspect of the present invention, the scanning body that fixes and holds the flat substrate is provided with a substrate pressing portion that prevents the flat substrate from warping. Since the substrate is prevented from warping by this configuration, it is possible to suppress the deterioration of the light amount unevenness in the plurality of light emitting elements due to the thermal expansion of the substrate due to the heat generation of the light emitting elements.

  According to a third aspect of the present invention, in the illuminating device according to the first aspect, the scanning body for fixing and holding the flat substrate is provided with a fin-shaped portion. The heat of the light emitting element can be dissipated through the body.

  According to a fourth aspect of the present invention, in the illuminating device according to the third aspect, the fin-shaped portion is provided at a lower portion of the light emitting element mounting position on the flat plate-like substrate. The heat can be efficiently conducted to the heat dissipating fins provided in the scanning body, and the heat of the light emitting element can be dissipated more effectively.

  According to a fifth aspect of the present invention, in the illuminating device according to any one of the first to fourth aspects, at least a portion of the scanning body on which the flat plate-like substrate is provided is formed of a heat radiating steel plate. Thus, the heat of the light emitting element can be dissipated more effectively through the scanning body.

  A sixth aspect of the present invention is the illumination device according to any one of the first to fifth aspects, wherein the scanning body is a traveling body that moves along the illuminated body, and the light source is mounted on the traveling body. It is applicable also to the thing of the structure which was made.

  According to a seventh aspect of the present invention, there is provided an illumination unit including a light source for illuminating a document and a mirror that guides reflected light from the document to a predetermined optical path, and an image sensor that converts the amount of reflected light into an image signal. And an illumination device according to any one of claims 1 to 6 as the illumination unit. The image reading device reads the image information by condensing the reflected light irradiated on the document on the image sensor. With this configuration, it is possible to prevent occurrence of an optical problem caused by heat generation of the light emitting element in the illuminating unit, and thus good image reading is performed.

  According to an eighth aspect of the present invention, in the image forming apparatus that includes an image reading unit and an image forming unit that receives the image information from the image reading unit and forms an image, the image reading unit according to the seventh aspect. The image reading apparatus is mounted. With this configuration, it is possible to prevent the occurrence of an optical problem caused by the heat generation of the light emitting element in the illumination unit of the image reading unit, and thus good image formation is performed.

  According to the illumination device of the present invention, a plate-like substrate on which a plurality of light emitting elements are arranged is directly attached to a scanning body, so that heat generated by light emission of the light emitting elements is spread on the substrate. Since it can quickly escape to the scanning body, it is possible to prevent the occurrence of optical problems in illumination caused by the heat generation of the light emitting element, and a conventional light source is placed on the scanning body through the holding member. The number of parts can be reduced as compared with the structure provided.

  According to the image reading apparatus and the image forming apparatus according to the present invention, it is possible to prevent the occurrence of an optical problem caused by heat generation of a light emitting element for illuminating a document or the like. To do.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an internal structure of an image reading apparatus for explaining an embodiment of the present invention. FIG. 2 is a perspective view showing a scanning part of the image reading apparatus in FIG. In the system unit 1, an illuminating device including an LED array 3 and a first mirror 4 that constitute a light source by arranging a plurality of light emitting elements (LEDs) on a flat substrate 2. The first traveling body 5 as a scanning body, the second traveling body 8 including the second mirror 6 and the third mirror 7, and the reflected light image from the original (not shown) on the contact glass 9 are captured. An image forming lens 11 for forming an image on a CCD (charge-coupled device) 10 of the element is provided, and in response to an image reading request signal for each line sent from a host computer (not shown), The first traveling body 5 and the second traveling body 8 are Respectively 2: while moving along the document on the contact glass 9 in the first speed, is configured to perform the image reading sequentially.

  FIG. 3 is a cross-sectional view showing the configuration of the first traveling body in the image reading apparatus of the present embodiment. A bent portion 5a is formed on a part of the first traveling body 5 made of a plate material. An LED array 3 in which a plurality of LEDs are arranged on a flat substrate 2 is fixed and held on the upper surface.

  FIG. 4 is a cross-sectional view showing a configuration of a first traveling body in a conventional image reading apparatus as a comparative example, in which the LED array 3 is fixedly held to the first traveling body 5 via an LED holding member 12. .

  In this embodiment, as shown in FIG. 3, there is no conventional LED holding member 12 shown in FIG. 4 in order to fix and hold the LED array 3, and the bent body is formed integrally with the first traveling body 5. The LED array 3 is directly fixed and held on the part 5a via an adhesive or the like. Thus, by directly attaching the LED array 3 to the first traveling body 5 formed of a sheet metal member having good thermal conductivity, the heat generated by the light emission of the LED array 3 is not spread over the substrate 2. It can quickly escape to the outside through the first traveling body 5. Further, since the LED holding member 12 in the comparative example is not necessary, the number of parts can be reduced.

  In the present embodiment, as shown in the cross-sectional view shown in FIG. 5 and the A arrow view of FIG. 5 shown in FIG. 6, the substrate pressing portion that restricts the occurrence of warpage in the bent portion 5 a of the first traveling body 5 in the substrate 2. 13 may be provided. 5 and 6, an L-shaped locking member is provided in the bent portion 5 a of the first traveling body 5 as the substrate pressing member 13, and the side end portion of the substrate 2 is locked.

  In this way, by providing the substrate pressing portion 13 for preventing the substrate 2 from warping due to the heat of the LED array 3 at the mounting portion of the first traveling body 5 in the LED array 3, the substrate 2 is deformed due to thermal expansion. Generation of (warp) can be prevented.

  Deformation (warping) of the substrate 2 shifts the angle of emitted light from the LED array 3 and causes uneven illumination, which adversely affects the illumination effect or reading effect. In this example, since the substrate 2 is pressed by the substrate pressing portion 13, the occurrence of the warp as described above is suppressed.

  By providing the substrate pressing portion 13 on the side of the substrate 2 where the LED array 3 is mounted (location close to the heat source), more effective heat removal can be expected. On the other hand, by releasing heat on the side opposite to the mounting surface of the LED array 3, an effect of preventing the occurrence of cracks in the substrate 2 can be expected.

  7 is a cross-sectional view showing a configuration of a modified example of the first scanning body shown in FIG. 3, and FIG. 8 is a view taken in the direction of arrow B in FIG. 7. In this example, the LED in the bent portion 5a of the first traveling body 5 is shown. A fin-shaped portion 14 for heat dissipation is formed on the mounting portion of the array 3.

  By installing the fin-shaped portion 14, the heat generated by the heat generated by the LED array 3 is transmitted to the first traveling body 5. The first traveling body 5 is driven so as to return to the home position after scanning and reading during the scanning operation of the document. The first traveling body 5 is cooled by this operation, and the cooling effect during scanning can be enhanced.

  Moreover, the hole 5b for the process in the 1st traveling body 5 produced in order to provide the fin-shaped part 14 can heighten a cooling effect more because the air of the fin vicinity can pass through.

  Further, by disposing the fin-shaped portion 14 directly below the LED array 3 that is a heating element, the heat dissipation effect can be further enhanced.

  Furthermore, if the first traveling body 5 is formed of a heat radiating steel plate having a high thermal conductivity, a higher heat radiating effect can be expected.

  As described above, by mounting the first traveling body 5 having the above-described configuration as the illumination device on the image reading apparatus as shown in FIGS. 1 and 2, the heat generated by the LED array 3 in the first traveling body 5 is caused. Since an optical problem can be prevented, good image reading is performed.

  FIG. 9 is a configuration diagram of a laser printer which is an embodiment of an image forming apparatus equipped with an image reading apparatus according to the present invention, and members corresponding to the structural members of the image reading apparatus described in FIGS. The same reference numerals are assigned and detailed description is omitted.

  The image forming unit 20 of the laser printer includes a photosensitive member 21, a charging roller 22, a developing device 23, a transfer roller 24, a cleaning device 25, a fixing device 26, an optical scanning device 27, a paper feed cassette 28, a registration roller pair 29, a feeding roller A paper roller 30, a paper transport path 31, a paper discharge roller 32, a paper discharge tray 33, and the like are included.

  The image reading unit 35 has the same configuration as that of the image reading apparatus described with reference to FIGS. 1 and 2, and the first traveling body (illumination device) according to the present invention as in the configuration of each of the above embodiments. The improved structure is adopted.

  The image reading unit 35 scans the first traveling body 5 and the second traveling body 8 to scan a document (not shown) on the contact glass 12 and forms a reflected light image from the document on the CCD 10. The CCD 10 photoelectrically converts the reflected light image of the document into an analog image signal and reads the document. Then, after the reading of the document is completed, the first traveling body 5 and the second traveling body 8 return to the home position.

  The analog image signal output from the CCD 10 is converted into a digital image signal by an analog / digital converter (not shown), and each image processing (binarization, multi-value conversion, Gradation processing, scaling processing, editing processing, etc.).

  The image processing signal is output to the optical scanning device 27, and a latent image is formed on the surface of the photosensitive member 21 by optical scanning of the photosensitive member 21 by the optical scanning device 27. The latent image on the photosensitive member 21 is developed with toner by the developing device 23, and the toner image is transferred onto the paper by the transfer roller 24. The transferred paper is subjected to a fixing process by the fixing device 26 and then discharged to the paper discharge tray 33 by the paper discharge roller 32.

  Thus, in this image forming apparatus, by adopting the improved structure of the first traveling body (illuminating device) according to the present invention as in the configuration of each of the above embodiments, in the first traveling body 5 of the image reading unit 35, Since it is possible to prevent the occurrence of an optical problem caused by the heat generated by the LED array 3, it is possible to form a good and high-quality image.

  The present invention is applied as an illumination device for illuminating a document in an image forming apparatus such as a copying machine, a facsimile machine, or a scanner, or an image reading apparatus.

1 is a schematic configuration diagram illustrating an internal structure of an image reading apparatus for describing an embodiment of the present invention. The perspective view which shows the traveling body part of the image reading apparatus of FIG. Sectional drawing which shows the structure of the 1st traveling body in the image reading apparatus of this embodiment. Sectional drawing which shows the structure of the 1st traveling body in the conventional image reading apparatus as a comparative example Sectional drawing which shows the structural example which provided the board | substrate holding part in this embodiment FIG. 5A view showing a configuration example provided with a substrate pressing portion in the present embodiment. Sectional drawing which shows the structure of the modification of the 1st scanning body in this embodiment FIG. 7B is a diagram showing a configuration of a modified example of the first scanning body in the present embodiment. 1 is a configuration diagram of a laser printer that is an embodiment of an image forming apparatus equipped with an image reading apparatus according to the present invention.

Explanation of symbols

2 Substrate 3 LED array 4 First mirror 4
5 1st traveling body 5a bending part 10 CCD
13 Substrate pressing part 14 Fin-shaped part 20 Image forming part 35 Image reading part

Claims (8)

A plurality of light emitting elements are arranged on a flat substrate, and a light source that illuminates an object to be illuminated with irradiation light from each light emitting element, and a predetermined light source that receives reflected light from the light source and the object to be illuminated In an illuminating device including a mirror that deflects in a direction and a scanning body on which the light source is mounted,
An illuminating device, wherein the flat substrate on which the light emitting elements are arranged is directly installed on the scanning body.   The illumination device according to claim 1, wherein a substrate pressing portion that prevents warpage of the flat substrate is provided on the scanning body that fixes and holds the flat substrate.   The illumination device according to claim 1, wherein a fin-shaped portion is provided on the scanning body for fixing and holding the flat substrate.   The lighting device according to claim 3, wherein the fin-shaped portion is provided below a light emitting element mounting position on the flat substrate.   The lighting device according to claim 1, wherein at least a portion of the scanning body on which the flat substrate is provided is formed of a heat radiating steel plate.   The lighting device according to claim 1, wherein the scanning body is a traveling body that moves along the body to be illuminated. An illumination unit comprising a light source for illuminating a document and a mirror for guiding reflected light from the document to a predetermined optical path, and an image sensor for converting the amount of reflected light into an image signal, and irradiating the document In the image reading apparatus that reads the image information by condensing the reflected light on the imaging element,
An image reading apparatus comprising the illumination device according to claim 1 as the illumination unit. An image forming apparatus including an image reading unit and an image forming unit that receives image information from the image reading unit and forms an image.
An image forming apparatus comprising the image reading device according to claim 7 as the image reading unit.

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