JP2010016496A - Image reader and image-forming device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid adverse influence by a conventional heating with a simple configuration, to prevent the number of components from increasing by eliminating the need for adding components for heat radiation, and to save space. <P>SOLUTION: A light source means is composed of a point light source 201i having a relatively small calorific value. A plurality of point light sources 201i are disposed while they are adjacent to a holding member 201c comprising a highly heat-conductive member, such as a metal material. Even if heat is generated by allowing the plurality of point light sources 201i to emit light, heat is radiated efficiently by the holding member 201c having satisfactory heat conductivity. Furthermore, the holding member made of the highly heat-conductive member, such as a metal material, is thinned. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image reading apparatus configured to read an original image by reflected light when the original is irradiated, and an image forming apparatus including the image reading apparatus.

  Generally, in image forming apparatuses such as copying machines, laser beam printers, facsimiles, and other various apparatuses, illumination light for reading a document emitted from a light source means is irradiated on the document, and the path of reflected light from the document is reflected. 2. Description of the Related Art Image reading apparatuses configured to read an image by condensing by an optical system and forming an image on a photoelectric conversion means while being appropriately changed by means are widely adopted.

  In such an image reading apparatus, there is a problem that the light source means acts as a heat source and affects the apparatus. In particular, in a so-called integrated illumination optical unit, reflecting means for changing the traveling direction of the light beam reflected on the document surface, a reduction optical system for collecting the reflected light of the document, and image formation of the light beam through the reduction optical system The photoelectric conversion means that receives light by the action is integrally disposed inside the unit together with a light source serving as a heat source. The distances between the reflecting means, the optical system, and the photoelectric conversion means are substantially constant, so that the structure is always susceptible to the heat generated from the light source means.

  However, since the conventional image reading apparatus often uses a plastic casing, the heat dissipation action of the entire apparatus is not good, so that the light emission state of the light source means as in the case of continuous operation, etc. When the operation continues, heat generation of the light source means may become excessive. In particular, in the case of an integrated illumination optical unit, for example, the casing, mirror, and lens are heated up due to the inability to dissipate heat in a region where the light flux on the document surface is reflected by the mirror, and the expansion, warpage, and the like. In some cases, misalignment may occur and the read image may be seriously affected.

  In addition, when the temperature of the light source rises too much, for example, parts arranged in the vicinity of the light source constituting the integrated illumination optical unit locally expand, etc. Distortion, twisting, and the like may occur, and even in that case, a serious adverse effect may occur on the read image as described above.

  As a countermeasure against such heat, conventionally, only a portion for holding the light source is made of metal, or fins are provided in the vicinity of the light source. However, in such a conventional configuration, although the heat radiation effect can be increased, there is a problem that the cost increases due to an increase in the number of parts, and the entire apparatus becomes large.

JP 2008-131121 A

  The present invention solves the above-mentioned conventional problems, and its purpose is to efficiently radiate the light source in a space-saving manner without increasing the number of parts, and to maintain a good read image due to the heat generated by the light source. An object of the present invention is to provide an image reading apparatus and an image forming apparatus including the image reading apparatus.

  In order to achieve the above object, in the present invention, an image is provided with light source means for emitting illumination light for reading a document and irradiating the document, and an optical system for imaging reflected light from the document on the photoelectric conversion means. In the reading apparatus, the light source means has a plurality of point light sources arrayed on a predetermined holding member, and at least a portion facing the point light source is formed by a good heat conducting member. Has been made.

  According to the present invention having such a configuration, the light source means is composed of a point light source having a relatively small calorific value, and a plurality of points as the light source means are provided on the holding member made of a good heat conducting member such as a metal material. Since the light source is always in contact, even if the light source means emits light, the heat is efficiently released by the holding member with good thermal conductivity, and the conventional heating is performed. This avoids the adverse effects caused by, and does not increase the number of parts because it is not necessary to add parts for heat dissipation. Furthermore, since the holding member made of a good heat conducting member such as a metal material becomes much thinner than that made of a conventional plastic material, space saving can be achieved.

  Further, the light source means in the present invention is disposed inside the integrated illumination optical unit, and the light beam emitted from the light source means and reflected from the surface of the original is inside the integrated illumination optical unit. The reflecting means for changing the traveling direction of the light and the photoelectric conversion means arranged at the position where the light beam reflected by the reflecting means is imaged by the optical system can be arranged.

  As described above, the present invention can be preferably applied to an integrated illumination optical unit in which the reflection means and the photoelectric conversion means are integrally arranged inside in addition to the light source means.

  In addition, the holding member in the present invention can be configured by the cover member of the integrated illumination optical unit. According to the present invention having such a configuration, heat is generated from a plurality of point light sources. However, good heat dissipation is performed through the cover member made of a good heat conducting member.

  Further, the holding member in the present invention can be configured to be fixed so as to be in contact with the point light source of the light source means. According to the present invention having such a configuration, This heat is directly conducted to the holding member, so that heat can be radiated more efficiently.

  Further, the holding member in the present invention at this time can be configured to be fixed so as not to contact the point light source of the light source means.

  As described above, according to the present invention, it is possible to obtain a heat radiation action even when heat conduction is performed indirectly because the heat generated from the point light source is not in contact with the holding member.

  In addition, when the optical system according to the present invention is configured to include an imaging lens, or includes a mirror having a curved reflecting surface, the holding member has a black surface. Even if it is a case, it can apply suitably.

  In particular, when the holding member is made of a metal material, heat conduction in the holding member is performed extremely well.

  Moreover, in this invention, it can be set as the structure provided with the member which presses the said light source means directly or indirectly to the said cover member, and if it does in that way, a cover member will be fixed simply and favorably.

  In the present invention, an image forming apparatus including any of the above-described image reading apparatuses can be provided. According to the present invention having such a configuration, the same effect can be obtained in the image forming apparatus. It is done.

  As described above, the image reading apparatus and the image forming apparatus provided with the image reading apparatus according to the present invention include the light source means that is a point light source with a relatively small calorific value and a highly heat conductive member such as a metal material. Even if the plurality of point light sources are arranged adjacent to the holding member and the light source means emits light and emits heat, it efficiently dissipates heat by the holding member with good thermal conductivity, While avoiding the negative effects of heating as in the past, it is not necessary to add parts for heat dissipation to prevent an increase in the number of parts, and the holding member made of a good heat conducting member such as a metal material is made thinner. Since the space can be saved, the reliability of the image reading apparatus can be greatly improved with a simple configuration.

  Hereinafter, an embodiment in which the present invention is applied to an image reading apparatus and a copying machine as an image forming apparatus including the image reading apparatus will be described in detail with reference to the drawings.

  First, as shown in FIG. 1, the overall configuration of a copying machine to which the present invention is applied includes a scanner unit B, an image forming unit C, and a sheet deck D in each unit of the image forming apparatus main body A. It has become. The scanner unit B arranged at the upper part of the image forming apparatus main body A constitutes an image reading apparatus that reads image information of a book document. An image forming unit serving as an image forming unit is provided below the scanner unit B. C is disposed, and a sheet deck D is assembled on the lower side of the image forming unit C.

  The scanner unit (image reading apparatus) B is configured such that the integrated illumination optical unit 201 according to the present invention is reciprocated directly below the platen glass 202. On the platen glass 202, books, recording paper, and the like are arranged. After the book original or sheet-like original made of the document is placed with the original surface facing downward, the back surface is pressed by the original pressure plate 203 that can be opened and closed with respect to the image forming apparatus main body A so that the book is set in a stationary state. It has become. When the user presses a reading start key (not shown) in this state, the above-described integrated illumination optical unit 201 moves below the platen glass 202 in the direction of arrow a to perform reading scanning, and image information on the original surface is obtained. Read.

  The image information of the original read by the integrated illumination optical unit 201 is processed by the image processing unit, converted into an electric signal, and then transmitted to the laser scanner 111 of the image forming unit C. Here, the image forming apparatus main body A functions as a copying machine when the processing signal of the image processing unit is input to the laser scanner 111 of the image forming unit C, and functions as a printer when the output signal of the external device (computer) is input. To do. The image forming apparatus main body A also functions as a facsimile apparatus if it receives a signal from another facsimile apparatus or transmits a signal from the image processing unit to another facsimile apparatus.

  On the other hand, the sheet cassette 1 is mounted below the image forming unit C described above. The sheet cassette 1 is composed of two feeding cassettes, a lower cassette 1a and an upper cassette 1b, and in this embodiment, a total of four cassettes can be mounted by the two feeding units U1 and U2. Has been made. One feeding unit U1 disposed on the upper side is detachably attached to the image forming apparatus main body A, and the lower feeding unit U2 is detachably attached to the sheet deck D. It has been.

  The sheet-like recording medium (paper) accommodated in the lower cassette 1a and the upper cassette 1b is fed out by the pickup roller 3 serving as a feeding rotating body, and for the cooperative operation of the feed roller 4 and the retard roller 5. After being separated and fed one by one, the sheet is conveyed to the registration roller 106 by the conveyance rollers 104 and 105, and is fed to the image forming unit C by the registration roller 106 so as to synchronize with an image forming operation described later. The In addition to the sheet cassette 1 described above, a manual feed tray 6 is disposed on the side surface of the image forming apparatus main body A, and a sheet on the manual feed tray 6 is fed to a registration roller 106 by a manual feed roller 7.

  The image forming unit C includes an electrophotographic photosensitive drum 112, an image writing optical system 113, a charging roller 116, a developing device 114, a transfer charging device 115, and the like. Then, a laser beam corresponding to image information emitted from the laser scanner 111 is scanned on the surface of the photosensitive drum 112 uniformly charged by the charging roller 116 by the image writing optical system 113 to form an electrostatic latent image. Then, the electrostatic latent image is developed by the developing device 114 to form a toner image. The toner image on the photosensitive drum 112 is provided with a transfer charger 115 on the first surface of a sheet-like recording medium (paper) sent from the registration roller 106 in synchronization with the rotation of the photosensitive drum 112. It is designed to be transferred at the transfer section. .

  Here, reference numeral 117 in the figure indicates a transport unit that transports the sheet-like recording medium on which the toner image is formed as described above, and reference numerals 118 and 119 indicate a fixing device and a discharge roller, respectively. . The conveyance unit 117 is configured to be able to convey a sheet-like recording medium (recording paper) as a heated material on which a toner image is formed, and the sheet-like recording medium on which the toner image is formed is The toner image is fixed on the surface by being heated and pressed by the unit 117 to the fixing device 118, and then discharged and stacked on the discharge tray 120 outside the apparatus by the discharge roller 119. Has been made.

  When images are recorded on both sides of a sheet-like recording medium (recording paper), the sheet-like recording medium ejected from the fixing device 118 is sandwiched between ejection rollers 119 and the trailing end of the sheet-like recording medium branches. When the point 207 is passed, the discharge roller 119 is rotationally driven in the reverse direction. As a result, the sheet-like recording medium is temporarily placed on the double-sided tray 121, and then conveyed by the conveying rollers 104 and 105 to reach the registration roller 106, and the second surface of the inverted sheet-like recording medium is placed on the second surface. In the same manner as described above, after an image is formed, it is discharged and stacked on the discharge tray 120.

[About Scanner Unit (Image Reading Device) B]
Here, the configuration of the scanner unit (image reading apparatus) B, which is a main part of the present invention, will be described. The scanner unit B has a frame having a substantially rectangular plane as shown in FIG. 2 in particular, and between the side frames B1 and B1 disposed at both ends in the sub-scanning direction of the frame. In addition, a pair of main scanning support shafts B2 and a sub-scanning support shaft B2 ′ having a round bar shape are attached in a substantially parallel state so as to span in the sub-scanning direction. One of the main scanning spindles B2 is slidably mounted with a sliding bearing 201b provided on the bottom surface of the housing chassis 201a constituting the integrated illumination optical unit 201 described above. The bottom surface portion of the housing chassis 201a is slidably mounted on the other sub-scanning support shaft B2 ′.

  As described above, the housing chassis 201a provided with light source means for emitting illumination light for reading a document, which will be described later, extends in the sub-scanning direction via the sliding bearing 201b provided on the housing chassis 201a. The integrated scanning optical unit 201 is reciprocally moved in the sub-scanning direction on the lower side of the platen glass 202. ing.

  On the other hand, an endless annular belt B3 is stretched so as to extend along the vicinity of the movable support shaft B2, and the housing chassis of the integrated illumination optical unit 201 described above is provided in the middle of the endless annular belt B3. 201a is fixed. The endless annular drive belt B3 is wound around the output shaft of the motor B5 via the pulley B4, and is moved so that the endless annular drive belt B3 is circulated by the rotational driving force of the motor B5. Has been made. Then, the integrated illumination optical unit 201 is reciprocated along the movement support shaft B2 by the circulating movement of the endless annular drive belt B3, and at that time, reading on the original surface on the platen glass 202 is performed. Has been made.

  As shown in FIGS. 3 and 4, the housing chassis 201a constituting the integrated illumination optical unit 201 has a document width direction (in FIG. 1) which is a main scanning direction orthogonal to the sub-scanning direction. It extends in an elongated shape along the vertical direction of the drawing. The housing chassis 201a is formed in a hollow box shape having an opening at the top, and covers the upper opening of the housing chassis 201a so as to cover the cover member 201c as a holding member. Is attached.

  The cover member 201c as the holding member is formed by a plate-like member made of a good heat conductor such as a metal material or a ceramic material, and includes mirrors 201m, 201n, 201p, 201q, 201r (see FIG. 4) is disposed above the reflection area, and in addition to the reflection areas by the respective mirrors, an imaging optical system and a CCD sensor (photoelectric conversion means) 201s to be described later from the original surface. Is arranged so as to substantially cover the entire upper portion of the chassis 201b so that external light other than the reflected light flux does not enter. As described above, the holding member in the present embodiment is configured by the cover member 201c that shields external light entering the interior of the integrated illumination optical unit.

  Further, as shown in FIGS. 5 and 6 in particular, the cover member (holding member) 201c has a pair of light source mounting surfaces 201h and 201h that are recessed in a step shape in the document width direction which is the main scanning direction. It is formed so as to extend in the direction perpendicular to the paper surface of FIG. The pair of light source mounting surfaces 201h and 201h are formed so as to face each other in the sub-scanning direction, and emit illumination light to the rising wall surfaces forming the steps of the light source mounting portions 201h and 201h. LED arrays 201i and 201i comprising a large number of point light sources constituting the light source means are attached. Each of the LED arrays 201i and 201i has a configuration in which micro light-emitting diodes that are point light sources are arrayed along the main scanning direction. The light-emitting surfaces 201j and 201i provided on the LED arrays 201i and 201i, respectively. 201j are arranged so as to face each other in the sub-scanning direction. Thus, in the present embodiment, the light source means has the LED arrays 201i and 201i that are a plurality of point light sources arrayed on a predetermined holding member made of the cover member 201c, and the holding member is The cover member 201c has at least a portion facing the light-emitting diode that is each of the point light sources formed of a good heat conducting member.

  Furthermore, the light guides 201k, 201k constituting the light guide means into which the illumination light emitted from the LED arrays 201i, 201i as the light source means is incident on the light emitting surfaces 201j, 201j of the LED arrays 201i, 201i. Are arranged adjacent to each other. The light guides 201k and 201k as the light guide means emit illumination light incident from the light source means in a predetermined direction to irradiate the original, and along the original width direction which is the main scanning direction. It is formed of an elongated transparent body that extends, and is disposed so as to cover the light emitting surfaces 201j and 201j of the LED arrays 201i and 201i from the front side. Thereby, the illumination light emitted from each point light source of each LED array 201 i is emitted toward the surface of the document on the platen glass 202. In FIG. 5, the description of the light guide is omitted.

  At this time, the pair of light guides 201k and 201k described above are arranged so as to contact the point light sources constituting the LED arrays 201i and 201i described above. That is, between the pair of light guides 201k and 201k, in particular, pressing members 201l and 201l as shown in FIG. 7 are provided from the outer side at both ends in the extending direction of the LED array 201i. It is mounted so as to be fitted. The width dimension in the main scanning direction of each pressing member 201l is set to be slightly larger than the interval between the light guides 201k and 201k, and is formed so as to be slightly wider. When the pressing member 201l is inserted between the light guides 201k and 201k in a press-fitted state, the light guides 201k and 201k are opposed to the light emitting surfaces 201j and 201j of the LED arrays 201i and 201i. It is contacted as if pressed. In addition, the LED arrays 201i and 201i are fixed in a state of being positively contacted with the light source mounting surfaces 201h and 201h of the cover member (holding member) 201c.

  Then, the luminous flux of the illumination light emitted from each of the LED arrays 201i through the light guide 201k is irradiated onto the document surface on the platen glass 202 disposed in the upper part of the cover member (holding member) 201c. The light beam reflected on the surface of the document is reflected by mirrors 201m, 201n, 201p, 201q, and 201r as reflecting means attached to the inner wall surface of the chassis chassis 201a, and the traveling direction is changed. A CCD sensor which is a photoelectric conversion means disposed at a position where an image is formed by an optical system that forms an image of reflected light from the original on a photoelectric conversion means, that is, an optical system including an imaging lens (not shown). A document image is formed at an appropriate magnification on 201 s and light is received, and reading of the document image is completed.

  At this time, as described above, since the direction of illumination is controlled by the optical function of the light guide 201k, the formation accuracy of the sheet metal constituting the cover member 201c is reduced, etc. For example, even when there is a slight gap between the light guide 201k and the LED array 201i, a situation in which the amount of reading light is significantly reduced by the optical function of the light guide 201k. Will not cause.

  As described above, in the present embodiment, the light source means is composed of the LED array 201i as a point light source having a relatively small calorific value, and the cover member 201c as a holding member made of a good heat conducting member such as a metal material. Since the LED arrays 201i and 201i are arranged so as to be always in contact with the light source mounting portions 201h and 201h, even if the LED arrays 201i and 201i emit light and generate heat, the heat conductivity is good. Heat is efficiently radiated by the cover member 201c. As a result, the adverse effects due to heating as in the conventional case are avoided, and the number of parts is not increased because there is no need to add parts. Further, the cover member 201c made of a good heat conducting member such as a metal material is much thinner than a conventional plastic material, thereby saving space.

  In particular, the cover member 201c constituting the holding member in the present embodiment is configured to be fixed so as to come into contact with the LED array 201i as the light source means, so that the heat generated from the light source means is covered. It is conducted directly to the member (holding member) 201c, so that heat can be radiated more efficiently.

  Such a heat radiation action according to the present invention is not limited to the case where the reduction optical system that forms an image of the reflected light from the original on the photoelectric conversion unit is configured to include the imaging lens as in the above-described embodiment. Even when it includes a mirror having a curved reflecting surface, it can be suitably applied. Moreover, even if it is a case where the cover member 201c as a holding member has a black surface, it is applicable similarly.

  As mentioned above, although the embodiment of the invention made by the present inventor has been specifically described, the present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the scope of the invention. Nor.

  For example, in the above-described embodiment, an LED array is used as the point light source constituting the light source means. However, the LED is irradiated from the light source means using a cold cathode tube or a xenon tube or the side surface of the light guide. Various light source means such as a type of light source means can be employed.

  In the above-described embodiment, the cover member as the holding member is in contact with the point light source of the light source means, but it is also possible to adopt a configuration in which the cover member is fixed so as to be non-contact. Even when the heat generated from the light source is indirectly conducted to the holding member, a heat radiation effect can be obtained. Thus, in this invention, it is possible to make it the structure provided with the member which presses a light source means directly or indirectly to a cover member, and in that way, a cover member is fixed simply and favorably.

  Furthermore, in the embodiment described above, the cover member is employed as the holding member, but other members may be used. Furthermore, in each of the above-described embodiments, the present invention is applied to an image reading apparatus configured to reciprocate during scanning, but also to an image forming apparatus that performs reading in a fixed state. The present invention can be similarly applied.

  In addition, the embodiment described above applies the present invention to a copying machine, but the present invention can be similarly applied to an image forming apparatus such as a printer or other apparatuses.

  As described above, the document reading apparatus and the image forming apparatus including the same according to the present invention can be widely applied to a wide variety of image forming apparatuses such as printers and copiers and other apparatuses.

1 is a longitudinal cross-sectional explanatory diagram showing an outline of the overall configuration of a copying machine as an example of an image forming apparatus to which the present invention is applied. FIG. 2 is an external perspective view illustrating the overall structure in a state where a cover is removed from the image reading apparatus used in the copying machine illustrated in FIG. 1. FIG. 3 is an external perspective view illustrating an integrated illumination optical unit used in the image reading device illustrated in FIG. 2. FIG. 4 is a cross-sectional explanatory view showing the internal structure of the integrated illumination optical unit shown in FIGS. 2 and 3. FIG. 5 is an external perspective explanatory view showing a part of an upper surface portion of the integrated illumination optical unit shown in FIGS. 2 to 4 in an enlarged manner. FIG. 6 is an explanatory cross-sectional view illustrating a part of the upper surface portion of the integrated illumination optical unit illustrated in FIGS. 2 to 5 in an enlarged manner. FIG. 5 is an external perspective explanatory view showing a part of an upper surface portion of the integrated illumination optical unit shown in FIGS. 2 to 4 in an enlarged manner.

Explanation of symbols

A Image forming device body B Scanner unit (image reading device)
B1 Both side frames B2 Moving support shaft B3 Endless annular belt B4 Pulley B5 Motor C Image forming unit D Sheet-like recording medium deck R Image transfer unit N Fixing nip unit 112 Photosensitive drum 115 Transfer roller 118 Fixing device 201 Integrated illumination optical unit 201a Case Body chassis 201b sliding bearing 201c cover member (holding member)
201h Light source mounting surface 201i LED array (point light source)
201j Light emitting surface 201k Light guide 201l Press member 201m, 201n, 201p, 201q, 201r Mirror 201s CCD sensor (photoelectric conversion means)
202 platen glass

Claims (12)

In an image reading apparatus comprising: a light source unit that emits illumination light for reading a document to irradiate the document; and an optical system that focuses reflected light from the document on a photoelectric conversion unit.
The light source means has a plurality of point light sources arrayed on a predetermined holding member,
The image reading apparatus according to claim 1, wherein at least a portion of the holding member that faces the point light source is formed of a heat-conductive member. The light source means is disposed inside an integrated illumination optical unit,
Inside the integrated illumination optical unit, reflecting means for changing the traveling direction of the light beam emitted from the light source means and reflected on the surface of the document, and the light beam reflected by the reflecting means is imaged by the optical system. The image reading apparatus according to claim 1, further comprising: a photoelectric conversion unit disposed at a predetermined position.   The image reading apparatus according to claim 2, wherein the holding member is constituted by a cover member of the integrated illumination optical unit.   The image reading apparatus according to claim 1, wherein the holding member is fixed so as to contact a point light source of the light source unit.   The image reading apparatus according to claim 1, wherein the holding member is fixed so as not to contact the point light source of the light source unit.   The image reading apparatus according to claim 1, wherein the point light source includes a light emitting diode.   The image reading apparatus according to claim 1, wherein the optical system includes an imaging lens.   The image reading apparatus according to claim 1, wherein the optical system includes a mirror having a curved reflecting surface.   The image reading apparatus according to claim 1, wherein the holding member is made of a metal material.   The image reading apparatus according to claim 1, wherein the holding member has a black surface.   4. The image reading apparatus according to claim 3, further comprising a member that directly or indirectly presses the light source unit against the cover member.   An image forming apparatus comprising the image reading apparatus according to claim 1.

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