JP2013219703A - Image reader and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader which allows for compaction, reduction in manufacturing costs, and enhancement of assemblability, and to provide a manufacturing method therefor.SOLUTION: The image reader includes line sensors 23a, 23b in which a plurality of image sensors are arranged in the main scanning direction, an optical system telecentric to the document surface side in the main scanning direction in which at least one concave mirror 11a, 11b, 12a, 12b and at least one plane mirror 22a, 22b are arranged alternately on an optical path for leading the light from a document to line sensors 23a, 23b, a first housing 10 holding the concave mirrors 22a, 22b, second housings 20a, 20b attached to the first housing 10 and holding the plane mirror 22a, and sensor substrates 24a, 24b attached to the second housings 20a, 20b and on which the line sensors 23a, 23b are mounted. The first housing 10 has a planar shape, and the second housings 20a, 20b have deep drawing shape.

Description

  The present invention relates to an image reading apparatus that optically reads an image of a subject and a manufacturing method thereof.

  In general, an image reading apparatus used for a copying machine, an image scanner, a facsimile, or the like includes a line sensor in which a plurality of imaging elements (photoelectric conversion elements) are arranged in the main scanning direction. When reading an image of a document, the line sensor reads the image in the main scanning direction and moves the optical unit including the line sensor relative to the document surface in the sub-scanning direction (for example, Patent Documents 1, 2, and 3). , 4).

  In such an image reading apparatus, the reading area of the document surface is divided into a plurality of parts in the main scanning direction, and the image of each divided area is read by the image sensor via the compound eye lens, and the output signal (read signal) of each image sensor. ) To restore the original image.

  Patent Document 1 discloses a first mirror array in which a plurality of concave mirrors facing a document surface are arranged in a row, a second mirror array in which a plurality of concave mirrors facing the first mirror array are arranged in a row, There is disclosed an image reading apparatus including a photosensor facing a second mirror array, and a pair of concave mirrors corresponding to the first mirror array and the second mirror array constituting a non-telecentric optical system.

  Patent Document 2 discloses an image reading apparatus including a first reflecting mirror facing the original surface and a second reflecting mirror arranged at the same height as the first reflecting mirror.

  Patent Document 3 includes an illumination unit that includes a light source and a light guide for illuminating an irradiated body, and an imaging optical system that converges reflected light from the irradiated body and an imaging unit that includes a light receiving unit. An image sensor in which an optical path from a light source to an irradiated body and an optical path from the irradiated body to a light receiving unit are separated is disclosed.

  Patent Document 4 discloses an image in which the optical system is composed of three structures of a first curved mirror unit, a second curved mirror unit, and a flat mirror unit in the configuration in which the optical path is separated as disclosed in Patent Document 3. A reader is disclosed.

Japanese Patent Laid-Open No. 11-008742 (paragraph 0010, FIG. 2) JP2003-295342A (paragraphs 0003 and 0004, FIG. 1) JP 2009-273000 A (paragraph 0021, FIG. 1) JP 2010-226596 A (paragraph 0015, FIG. 1)

  However, in the image reading apparatus described in Patent Document 1, since concave mirrors are arranged on both the document side and the photosensor side, the structure of the housing (not specifically disclosed in Patent Document 1). Seems to be complicated. In addition, the distance from the document surface to the photosensor tends to be long, and there is a problem that it is difficult to reduce the dimension of the image reading apparatus in the height direction (a direction orthogonal to both the main scanning direction and the sub-scanning direction).

  In addition, the image reading apparatus described in Patent Document 2 has a configuration in which the first reflecting mirror and the second reflecting mirror are arranged at the same height (facing in a direction parallel to the document surface), so that the sub-unit of the optical unit. There is a problem that the dimension in the scanning direction becomes large.

  Further, in the image sensor described in Patent Document 3, the optical path from the light source to the irradiated body and the optical path from the irradiated body to the light receiving unit are bent optical paths, respectively, and the height dimension of the image sensor is set. Although there is an advantage of suppressing it, the dimension in the sub-scanning direction is conversely increased. In addition, since the number of reflection mirrors increases to bend the optical path, there is a problem that the manufacturing cost increases.

  Further, in the image reading apparatus described in Patent Document 4, the structure can be simplified and the assembly accuracy can be improved, but the mirror surface (a reflective film such as aluminum) of each curved mirror unit or flat mirror unit is formed. At this time, it is difficult to form a reflective film having a uniform film thickness on a complex-shaped mirror unit. In addition, there is a possibility that aluminum or the like adheres in addition to the part forming the mirror surface.

  SUMMARY An advantage of some aspects of the invention is that it provides an image reading apparatus that can be reduced in size, reduced in manufacturing cost, and improved in assembling ability, and a manufacturing method thereof. is there.

  An image reading apparatus according to the present invention includes a line sensor in which a plurality of image sensors are arranged in the main scanning direction, and at least one concave mirror and at least one plane mirror on an optical path that guides light from the document surface to the line sensor. Are alternately arranged, a telecentric optical system on the document surface side in the main scanning direction, a first housing holding a concave mirror, a second housing attached to the first housing and holding a plane mirror, A sensor board mounted on the second housing and having a line sensor mounted thereon. The first housing has a flat plate shape, and the second housing has a deep drawing shape.

  In the image reading apparatus according to the present invention, of the concave mirror and the flat mirror constituting the optical system, a concave mirror having a high required assembly accuracy is attached to the flat plate-shaped first housing, and the required assembly accuracy is relatively high. A low plane mirror is attached to the deeply drawn second housing. Therefore, the finishing accuracy and positioning accuracy of the mounting surface of the flat mirror of the second housing can be relaxed. In addition, by forming the first casing to which the concave mirror is mounted into a flat plate shape, machining becomes easy, and it is easy to improve the positional accuracy such as flatness and positioning holes, and can meet the demand for high assembly accuracy. .

It is sectional drawing which shows the structure of the principal part of the image reading apparatus in Embodiment 1 of this invention. It is a schematic diagram which shows the optical system of the optical unit of the image reading apparatus in Embodiment 1 of this invention. It is a top view which shows the structure of the optical unit of the image reading apparatus in Embodiment 1 of this invention. It is a perspective view which shows the structure of the concave mirror unit of the image reading apparatus in Embodiment 1 of this invention. It is a perspective view which shows the structure of the plane mirror unit and side stand of the image reading apparatus in Embodiment 1 of this invention. It is a disassembled perspective view which shows the structure of the plane mirror unit of the image reading apparatus in Embodiment 2 of this invention. It is a disassembled perspective view which shows the structure of the concave mirror unit of the image reading apparatus in Embodiment 2 of this invention. It is a top view which shows the structure of the 1st housing | casing of the image reading apparatus in Embodiment 2 of this invention. It is a top view which shows the state which attached the concave mirror to the 1st housing | casing of the image reading apparatus in Embodiment 2 of this invention. FIG. 10 is a top view showing a state in which the second casing is attached to the first housing from the state of FIG. 9. It is a top view which shows the state which attached the flat mirror and the sensor board | substrate to the 2nd housing from the state of FIG. It is a top view which shows the state which attached the side stand and IR cut filter to the 1st housing from the state of FIG. It is a top view which shows the state which attached the illumination optical system to the 2nd housing from the state of FIG.

Embodiment 1 FIG.
<Overall configuration>
FIG. 1 is a cross-sectional view in the sub-scanning direction showing the configuration of the main part of the image reading apparatus according to Embodiment 1 of the present invention. FIG. 2 is a schematic diagram illustrating an optical system of the optical unit 1 of the image reading apparatus according to the first embodiment. FIG. 3 is a top view illustrating the configuration of the optical unit 1 of the image reading apparatus according to the first embodiment. 1 corresponds to a cross-sectional view indicated by arrows II in FIG.

  As shown in FIG. 1, the image reading apparatus according to the first embodiment includes a platen glass 40 as a document table on which a document is placed, and an optical unit 1 disposed to face the platen glass 40. . In FIG. 1, the direction orthogonal to the paper surface is the main scanning direction (X direction), and the left-right direction in the figure is the sub-scanning direction (Y direction). A direction orthogonal to the X direction and the Y direction is a Z direction, a direction from the optical unit 1 toward the platen glass 40 is a + Z direction (upward), and an opposite direction is a -Z direction (downward).

  The optical unit 1 includes a concave mirror unit 100 having concave mirrors 11a, 11b, 12a and 12b, flat mirror units 200a and 200b having flat mirrors 22a and 22b and sensor substrates 24a and 24b, and LED substrates 31a and 31b. Illumination units 300a and 300b are provided. The concave mirror unit 100 and the plane mirror units 200a and 200b constitute an imaging optical system, and the illumination units 300a and 300b constitute an illumination optical system.

First, the basic configuration of the optical system of the optical unit 1 will be described.
The optical unit 1 has line sensors 23 a and 23 b on both sides in the Y direction with the image reading position 50 on the platen glass 40 as the center. Each of the line sensors 23a and 23b is a one-dimensional image sensor in which a plurality of image sensors are arranged in the X direction. The line sensors 23a and 23b are attached to the sensor substrates 24a and 24b, respectively.

  A concave mirror 11a, a plane mirror 22a, and a concave mirror 12a are arranged along an optical path that guides light from the document surface to the line sensor 23a, and these constitute one optical system 60. Similarly, a concave mirror 11b, a plane mirror 22b, and a concave mirror 12b are arranged along an optical path that guides light from the document to the line sensor 23b, and these constitute another optical system 70. .

  Here, the case where each optical system has two concave mirrors and one plane mirror will be described. However, the present invention is not limited to such a configuration, and the number of concave mirrors is N (N is 2 or more). (Natural number), the number of plane mirrors may be N−1. That is, it is sufficient that the number of concave mirrors is one more than the number of plane mirrors.

  The concave mirror 11a is disposed to face the platen glass 40 and reflects light from the document surface in a substantially + Z direction (upward). A plane mirror 22a is disposed in the traveling direction of the reflected light of the concave mirror 11a, and reflects light from the concave mirror 11a in a substantially −Z direction (downward). A concave mirror 12a is disposed in the traveling direction of the reflected light of the plane mirror 22a, and the light from the plane mirror 22a is reflected in a substantially + Z direction and is incident on the line sensor 23a. An aperture (aperture) 21a is provided between the flat mirror 22a and the concave mirror 12a.

  Similarly, the concave mirror 11b is disposed to face the platen glass 40, and reflects light from the document surface in a substantially + Z direction. A plane mirror 22b is disposed in the traveling direction of the reflected light of the concave mirror 11b, and reflects light from the concave mirror 11b in a substantially −Z direction. A concave mirror 12b is disposed in the traveling direction of the reflected light of the plane mirror 22b, and reflects light from the plane mirror 22b in a substantially + Z direction and enters the line sensor 23b. An aperture 21b is provided between the flat mirror 22b and the concave mirror 12b.

  The optical system 60 including the concave mirror 11a, the flat mirror 22a, the concave mirror 12a, and the line sensor 23a, and the optical system 70 including the concave mirror 11b, the flat mirror 22b, the concave mirror 12b, and the line sensor 23b have an image reading position 50. As centers, they are arranged symmetrically in the Y direction. The concave mirrors 11a, 11b, 12a, 12b and the plane mirrors 22a, 22b are made of resin, for example.

  FIG. 2 is a diagram illustrating the operation of the optical system including the concave mirror 11a (11b), the flat mirror 22a (22b), the concave mirror 12a (12b), and the line sensor 23a (23b).

  In FIG. 2, a set of chief rays from the document surface (image reading position 50) to the image sensor 23a (23b) is indicated by a symbol C. Since the concave mirror 11a (11b) and the concave mirror 12a (12b) have a lens effect as described later, they are shown in a lens shape in FIG. FIG. 2 shows a reading range D of the document surface corresponding to one optical system. Here, it is assumed that there are image elements 1 to 6 as read images in the reading range D of the document surface.

  The concave mirror 11a (11b) and the concave mirror 12a (12b) have a lens effect by the power (refractive power) in the X direction and Y direction of the respective reflecting surfaces. The aperture 21a (21b) is disposed at the rear focal point of the concave mirror 11a (11b), thereby realizing a telecentric optical system on the document surface side (subject side).

  The optical system 60 including the concave mirror 11a, the flat mirror 22a, the concave mirror 12a, and the line sensor 23a configured as described above is arranged at a predetermined pitch (arrangement interval) in the X direction. Similarly, the optical system 70 including the concave mirror 11b, the flat mirror 22b, the concave mirror 12b, and the line sensor 23b is arranged at the above pitch in the X direction.

  Furthermore, the optical system 60 including the concave mirror 11a, the flat mirror 22a, the concave mirror 12a, and the line sensor 23a, and the optical system 70 including the concave mirror 11b, the flat mirror 22b, the concave mirror 12b, and the line sensor 23b are only a half pitch. They are arranged out of alignment with each other. With this configuration, the document surface is divided in the X direction, and the image of each divided area (reading range D) can be alternately read by the line sensor 23a and the line sensor 23b.

  By combining the read signals of the line sensor 23a and the line sensor 23b, the original image is restored. The original image can be restored by a method disclosed in, for example, Japanese Patent Application Laid-Open No. 2010-226596.

<Configuration of concave mirror unit>
As shown in FIG. 1, the concave mirrors 11 a, 11 b, 12 a, and 12 b (that is, an aggregate of concave mirrors) are attached to the first housing 10. The first casing 10 is a flat plate-like structure disposed in parallel with the platen glass 40, and is made of, for example, aluminum. These concave mirrors 11a, 11b, 12a, 12b and the first housing 10 constitute a concave mirror unit 100. A reference surface and positioning holes 113 and 123 (positioning means) for mounting the concave mirrors 11a, 11b, 12a, and 12b are provided on the upper surface of the first casing 10, that is, the surface facing the platen glass 40.

  FIG. 4 is a perspective view showing the configuration of the concave mirror unit 100. As described above, the concave mirrors 11a and 12a belong to the same optical system 60 (FIG. 1), and the concave mirrors 11b and 12b belong to the same optical system 70 (FIG. 1). FIG. 4 shows an example in which two concave mirrors 11a, 11b, 12a, and 12b are arranged in the X direction for convenience of illustration, but in reality, a larger number of concave mirrors are arranged in the X direction. It is arranged.

  The concave mirror 11a and the concave mirror 11b have the same shape (thus having the same reflective surface shape), are symmetrical about the image reading position 50 in the Y direction, and are shifted by a half pitch in the X direction. Is arranged. Similarly, the concave mirror 12a and the concave mirror 12b have the same shape and are arranged symmetrically in the Y direction and shifted by a half pitch in the X direction with the image reading position 50 as the center.

  Since the concave mirrors 11a, 11b, 12a, and 12b attached to the first housing 10 all have power and have a lens action, high attachment accuracy is required. In the present embodiment, since the first casing 10 has a flat plate shape, the machining of the surface to which the concave mirrors 11a, 11b, 12a, 12b are attached as compared with a deformed casing such as a deep drawing. Is easy. Thereby, it becomes easy to obtain high flatness and position accuracy of the positioning hole, and the manufacturing cost can be reduced.

  Note that positioning grooves 101 a and 101 b extending in the X direction are formed on the upper surface of the first housing 10. In the groove 101a, positioning holes 15a and 15b (positioning means) which are round holes for positioning second casings 20a and 20b described later are formed.

  The first housing 10 has screw holes 104 and 109 into which screws 603 and 605 for fixing the second housings 20a and 20b are screwed, and screw holes into which screws 602 for fixing the side stand 42 described later are screwed. 102 and the positioning hole 17 in which the positioning boss of the side stand 42 engages are formed.

<Configuration of flat mirror unit>
As shown in FIG. 1, the plane mirror 22a and the sensor substrate 24a are attached to the second housing 20a. The plane mirror 22b and the sensor substrate 24b are attached to the second housing 20b. The plane mirror unit 200a is configured by the plane mirror 22a, the sensor substrate 24a, and the second housing 20a. Further, the plane mirror unit 200b is configured by the plane mirror 22b, the sensor substrate 24b, and the second housing 20b.

  The second housings 20a and 20b are attached to the upper surface of the first housing 10 (the surface facing the platen glass 40). The second casings 20a and 20b are both molded products having a deep drawing shape, and are made of, for example, aluminum or resin. Here, the “deep drawing shape” refers to a shape formed by die casting, pressing, cutting, or the like and having a depth equal to or greater than the plate thickness.

  Planar mirrors 22a and 22b and sensor substrates 24a and 24b (line sensors 23a and 23b are mounted) are positioned on the upper surfaces (surfaces facing the platen glass 40) of the second casings 20a and 20b, It is fixed. Further, the apertures 21a and 21b shown in FIG. 1 are formed in the second casings 20a and 20b by integral molding.

  FIG. 5 is a perspective view showing the configuration of the flat mirror units 200a and 200b together with a side stand 42 described later. The second housings 20a and 20b are arranged symmetrically in the Y direction and shifted by a half pitch in the X direction around the image reading position 50 (FIG. 1).

  The second housing 20a has the highest height portion (projecting portion) 201 at the position closest to the image reading position 50 (FIG. 1) in the Y direction, and has the mounting surface 202 that is an inclined surface. Yes. The attachment surface 202 has an inclination that decreases in height as the distance in the Y direction from the image reading position 50 increases.

  A mounting hole 205 for mounting the flat mirror 22a is formed in the protruding portion 201 of the second housing 20a. The flat mirror 22a is positioned and fixed on the inner side of the mounting hole 205 according to the outer shape reference.

  The mounting surface 202 is formed with a positioning hole 28a for positioning the sensor substrate 24a and an opening 206 for allowing light incident on the line sensor 23a mounted on the sensor substrate 24a to pass therethrough. The sensor substrate 24a is positioned and fixed at a predetermined position on the mounting surface 202. In FIG. 5, for convenience of illustration, the sensor substrate 24a is omitted, and only the line sensor 23a mounted on the sensor substrate 24a is shown.

  Similarly, a plane mirror 22b and a sensor substrate 24b are attached to the second casing 20b. In FIG. 5, for convenience of illustration, the sensor substrate 24b is omitted, and only the line sensor 23b mounted on the sensor substrate 24b is shown.

  The sensor substrates 24a and 24b are configured so that the line sensor 23a mounted on the sensor substrate 24a and the line sensor 23b mounted on the sensor substrate 24b are symmetrical in the Y direction with respect to the image reading position 50 and half in the X direction. It is positioned so as to be arranged at a position shifted from the pitch, and is fixed to the second casings 20a and 20b.

  The sensor boards 24a and 24b are obtained by mounting line sensors (imaging devices) 23a and 23b on printed boards such as FR4 having the same size. The mounting positions and the wiring patterns of the imaging elements on the sensor substrate 24a and the sensor substrate 24b are set symmetrically with respect to the Y direction.

  The plane mirror 22a and the line sensor 23a belong to the same optical system 60 (FIG. 1), and the plane mirror 22b and the line sensor 23b belong to the same optical system 70 (FIG. 1). The flat mirror 22a and the flat mirror 22b have the same shape and are arranged symmetrically in the Y direction with the image reading position 50 as the center and shifted by a half pitch in the X direction. FIG. 5 shows an example in which two plane mirrors 22a and 22b are arranged in the X direction for convenience of illustration, but actually, a larger number of plane mirrors are arranged in the X direction. Yes.

  The second housings 20a and 20b are formed with through holes 204 and 209 through which screws 603 and 605 (FIG. 3) for fixing them to the first housing 10 are passed. By screwing screws 603, 605 (FIG. 3) that have passed through the through holes 204, 209 of the second housing 20a, 20b into the screw holes 104, 109 (FIG. 4) of the first housing 10, The second casings 20 a and 20 b are fixed to the first casing 10.

  Side stands 42 (only one side stand 42 is shown in FIG. 5) are provided at both ends in the X direction of the second casings 20a and 20b so that external light does not enter through a gap corresponding to a half pitch. It has been.

  The side stand 42 has a through hole 422 in the lower flange portion 421. The side stand 42 is fixed to the first casing 10 by screwing the screw 602 (FIG. 3) that has passed through the through hole 422 of the side stand 42 into the screw hole 102 (FIG. 4) of the first casing 10. .

  The side stand 42 includes a cover 420 positioned at the end of the optical unit 1 in the X direction, a block-shaped wall 425 formed on the inner side in the X direction, and a light-shielding part 424 that protrudes inward in the X direction from the wall 425. have.

  The wall portion 425 abuts on the end surface 208 in the X direction of the second casing 20a. The light shielding portion 424 has an X-direction dimension corresponding to a gap corresponding to a half pitch between the second casing 20a and the second casing 20b, and is in contact with the X-direction end surface 208 of the second casing 20b so as to be external light. Prevent the intrusion. The wall portion 425 has a role of supporting illumination optical system units 300a and 300b described later on the upper surface thereof.

<Lighting unit>
As shown in FIG. 1, the illumination units (illumination optical systems) 300a and 300b are arranged on both sides in the Y direction with the image reading position 50 as the center, and are positioned above the second mirror units 200a and 200b, respectively. . The illumination units 300a and 300b are arranged above the second housings 20a and 20b, and are reflective mirrors 30a and 30b facing the platen glass 40, and LEDs (light-emitting diodes) that emit light toward the reflective mirrors 30a and 30b. LED boards 31a and 31b, and heat radiating plates 32a and 32b for radiating the heat of the LEDs.

  The reflecting mirrors 30a and 30b have a concave reflecting surface M on the upper surface (the surface facing the platen glass 40), and the light irradiated from the LED substrates 31a and 31b is used as a subject surface (image reading). Reflects towards position 50). The reflection mirrors 30a and 30b have flat plate portions to which the LED substrates 31a and 31b are fixed. The flat plate portion has a predetermined angle with respect to the reflection surface M.

  Each of the LED substrates 31a and 31b has a plurality of LEDs arranged in the X direction. The LED substrates 31a and 31b are fixed to the flat plate portions of the reflecting mirrors 30a and 30b with their respective LED sides facing the reflecting surface M.

  The heat sinks 32a and 32b are attached to substantially the entire back surface of the LED substrates 31a and 31b (surface opposite to the reflection mirrors 30a and 30b). The LED substrate 31a and the heat radiating plate 32a are fixed to the reflecting mirror 30a by screws 601. The LED substrate 31b and the heat radiating plate 32b are fixed to the reflecting mirror 30b by screws 601.

  Here, an illumination unit in which a plurality of LEDs are arranged in the X direction (main scanning direction) is used, but a light guide may be used instead of arranging the plurality of LEDs in the X direction.

  An IR (ultraviolet) cut filter 41 is attached between the second housings 20a and 20b. The IR cut filter 41 is disposed between the platen glass 40 and the concave mirrors 11a and 11b, and is provided with a coating for shielding infrared rays. The IR cut filter 41 is for preventing infrared light (light having a wavelength of 700 nm or more) from entering the line sensors 23a and 23b.

  The IR cut filter 41 may be made of a transparent resin or glass, or may be made of a transparent thin sheet. Further, the IR cut filter 41 is not limited to be placed between the platen glass 40 and the concave mirrors 11a and 11b, and may be installed in another place as long as it is on the optical path from the document surface to the line sensors 23a and 23b.

  The optical unit 1 configured in this manner moves relative to the platen glass 40 in the Y direction (sub-scanning direction). For example, the entire optical unit 1 is mounted on a carriage that can move in the Y direction, and is moved in the Y direction by a motor or the like.

<Assembly method>
Next, a method for assembling the optical unit 1 according to Embodiment 1 will be described. First, as shown in FIG. 4, concave mirrors 11a, 11b, 12a, and 12b are fixed to the upper surface (reference surface) of the first housing 10. At this time, the positioning bosses 112 and 122 (FIG. 1) formed on the lower surfaces of the concave mirrors 11a, 11b, 12a and 12b are moved upward in the positioning holes 113 and 123 (FIG. 1) formed in the first housing 10, respectively. Fit from. It is possible to fix each concave mirror to the upper surface of the first casing 10 without play by applying an adhesive in advance to the lower surfaces of the concave mirrors 11a, 11b, 12a, 12b and pressing it with a jig or the like. it can.

  Next, the second casings 20a and 20b are attached to the upper surface of the first casing 10, respectively. At this time, the positioning bosses formed on the lower surfaces of the second casings 20a and 20b are fitted into the positioning holes 15a and 15b and the grooves 101a and 101b formed in the first casing 10, thereby the second casing. 20a and 20b are positioned with respect to the first housing 10. Further, the screws 603 and 605 (FIG. 3) are screwed into the screw holes 104 and 109 (FIG. 4) through the through holes 204 and 209, thereby fixing the second casings 20a and 20b to the first casing 10. .

  When the second casings 20 a and 20 b are attached to the upper surface of the first casing 10, the light shielding wall 207 (FIG. 5) that is the inner wall of the second casings 20 a and 20 b is fixed to the first casing 10. The concave mirrors 11a, 11b, 12a, and 12b are arranged so as to surround each optical system (cell).

  After that, the plane mirrors 22a and 22b are attached to the attachment holes 205 (FIG. 5) of the second housings 20a and 20b. Since the plane mirrors 22a and 22b have a high likelihood of the mounting position in the in-plane direction, the flat mirrors 22a and 22b are mounted in the mounting holes 205 on the basis of the outer shape.

  Further, the sensor substrates 24a and 24b are attached to the attachment surfaces 202 (FIG. 5) of the second housings 20a and 20b. At this time, the positioning holes 28a and 28b provided in the second housings 20a and 20b and the positioning holes provided in the sensor substrates 24a and 24b are aligned using a jig such as a positioning pin (parallel pin). Then, the optical axes of the concave mirrors 11a, 11b, 12a, and 12b are made to coincide with the optical axes of the corresponding line sensors 23a and 23b.

  Next, the side stand 42 is attached to the first casing 10. At this time, a positioning boss provided on the lower surface of the side stand 42 is fitted into the positioning hole 17 (FIG. 4) provided in the first housing 10 from above, and the side stand 42 is positioned with respect to the first housing 10. To do. Further, the screw 602 (FIG. 3) is screwed into the screw hole 102 (FIG. 4) through the through hole 422 of the side stand 42, and the side stand 42 is fixed to the first housing 10. At this time, the wall portion 425 and the light shielding portion 424 of the side stand 42 come into contact with the side surfaces of the second housings 20a and 20b, and the intrusion of external light is blocked.

  Furthermore, as shown in FIG. 3, the IR cut filter 41 is attached so as to be bridged between side stands 42 (only one is shown in the figure) provided on both sides in the X direction.

  Finally, the lighting units 300a and 300b are fixed to the side stand 42 using screws 610 (FIG. 3). At this time, the illumination units 300a and 300b are positioned by fitting the positioning pins 43 (FIG. 5) on the upper surface of the side stand 42 into the positioning holes formed at the X-direction ends of the illumination units 300a and 300b.

  As described above, the assembly of the optical unit 1 can be performed entirely from above the first casing 10 (on the side of the platen glass 40). In particular, since all the components are sequentially attached from above with reference to the reference surface of the first housing 10, it is easy to obtain the positional accuracy of each component. Moreover, since all components can be attached by access from above, workability is good.

  Moreover, in the assembled optical unit 1, it is divided for each optical system (cell) by the light shielding wall 207 of the second casings 20a and 20b. This prevents light from adjacent optical systems from entering each optical system.

<Operation>
The operation of the image reading position configured as described above will be described.
In FIG. 1, the light emitted from the LED substrate 31a of the illumination unit 300a is reflected by the reflecting surface M of the reflecting mirror 30a and irradiates the document surface on the platen glass 40.

  The light 50 a reflected from the document surface passes through the IR cut filter 41 and enters the concave mirror 11 a of the concave mirror unit 100. The light reflected by the reflecting surface of the concave mirror 11a enters the flat mirror 22a of the flat mirror unit 200a while gently converging.

  The light reflected by the reflecting surface of the flat mirror 22a travels toward the concave mirror 12a of the concave mirror unit 100, but forms a crossover only in the main scanning direction at a position passing through the aperture 21a. Then, after excess light is cut by the aperture 21a, it enters the concave mirror 12a.

  The light reflected by the concave mirror 12a is again condensed on the light receiving surface of the line sensor (imaging device) 23a of the plane mirror unit 200. Thus, the image of the original surface is formed on the light receiving surface of the line sensor 23a by the optical system 60 having the concave mirror 11a, the flat mirror 22a, and the concave mirror 12a.

  Similarly, the light emitted from the LED substrate 31b of the illumination unit 300b is applied to the original surface, and the light 50b reflected on the original surface is converted into the IR cut filter 41, the concave mirror 11b, the flat mirror 22b, the aperture 21b, and the concave surface. The light is condensed on the light receiving surface of the line sensor (imaging device) 23b via the mirror 12b. That is, an image of the original surface is formed on the light receiving surface of the line sensor 23b by the optical system 70 having the concave mirror 11b, the flat mirror 22b, and the concave mirror 12b.

  In this manner, the images formed on the line sensors 23a and 23b are sequentially connected by the optical systems 60 and 70 alternately arranged at a constant interval in the X direction (main scanning direction), so that the image reading position 50 can be obtained. An image of one line in the X direction is generated. Further, by moving the optical unit 1 in the Y direction with respect to the document surface, a two-dimensional image of the document surface can be acquired.

<Effect>
The effect of the image reading position configured as described above will be described.
In the image reading apparatus according to the first embodiment, the concave mirrors 11a, 11b, 12a, and 12b with high required assembly accuracy are attached to the flat plate-shaped first housing 10, and the required flat assembly mirror 22a with relatively low assembly accuracy. , 22b are attached to the deeply drawn second casings 20a, 20b. Thereby, the finishing precision and positioning precision of the attachment surface of the plane mirrors 22a and 22b of the second housings 20a and 20b can be relaxed.

  Further, by forming the first housing 10 to which the concave mirrors 11a, 11b, 12a, and 12b are formed into a flat plate shape, machining becomes easy, and the flatness and the positioning accuracy such as the positioning holes can be improved. Thereby, the request | requirement of high assembly precision can be responded.

  Further, since the sensor boards 24a and 24b on which the line sensors 23a and 23b are mounted are arranged on the side close to the original surface (that is, the flat mirror units 200a and 200b), the sensor boards 24a and 24b and the platen glass 40 are arranged. There are no other parts in between. Therefore, even when the image reading apparatus is mounted on a copier or the like that is the final product, the sensor substrates 24a and 24b can be easily accessed by simply removing the platen glass 40. Therefore, attachment, removal, replacement, circuit repair and the like of the sensor substrates 24a and 24b can be easily performed.

  Further, by increasing the number N of concave mirrors included in each of the optical systems 60 and 70 by one more than the number of plane mirrors (N-1), the sensor substrates 24a and 24b are placed on the document surface as described above. A configuration arranged on the near side can be easily realized.

  In addition, the telecentric optical system 60 and the optical system 70 in the X direction (main scanning direction) are shifted by half a pitch on both sides in the Y direction (sub scanning direction) with the image reading position 50 as the center, thereby achieving high definition. The optical unit 1 can be configured in a small size while corresponding to the increase in size.

  Note that the second housing has a structure divided into two parts (20a, 20b) in the Y direction in order to facilitate the molding process, but adopting such a divided structure. However, there is no adverse effect on optical performance. However, you may comprise the 2nd housing | casing 20a, 20b integrally.

  In addition, since the apertures 21a and 21b are formed integrally with the second casings 20a and 20b, it is possible to reduce the number of parts for fixing and form the apertures 21a and 21b without interposing other parts. Therefore, it is advantageous in terms of improving assembly accuracy.

  Further, since the second casings 20a and 20b have a deep drawing shape, it is possible to easily block the light beams of the adjacent optical systems. Further, in the case of a deep-drawn housing, the space for mounting the mirror is less than that of a flat housing, and the mounting surface is difficult to process, but the flat mirror can be made thinner than the concave mirror. Above, the positional accuracy in the in-plane direction has a relatively high likelihood. Therefore, the flat mirrors 22a and 22b of the second casings 20a and 20b having a deep drawing shape can be attached relatively easily even in a small space.

Embodiment 2. FIG.
<Configuration>
Next, a second embodiment of the present invention will be described. FIG. 6 is an exploded perspective view showing the configuration of the plane mirror units 200a and 200b of the image reading apparatus according to Embodiment 2 of the present invention.

  As in the first embodiment, the optical unit of the image reading apparatus according to the second embodiment includes the concave mirror unit 100, the flat mirror units 200a and 200b, and the illumination optical systems 300a and 300b as main components. However, compared with the first embodiment, the number of parts of the concave mirror unit 100 and the flat mirror units 200a and 200b is reduced, and workability is improved.

  As shown in FIG. 6, in the second embodiment, long flat mirrors 25a and 25b that are long in the X direction are attached to the second casings 20a and 20b, respectively. A plurality of window portions 27a and 27b are formed at locations where the flat mirrors 25a and 25b of the protruding portion 201 of the second casings 20a and 20b are fixed.

  The window 27a is provided for each cell (optical system) partitioned by the light shielding wall 207 of the second casing 20a, and is formed in the same shape within the same plane. Similarly, the window portion 27b is provided for each cell partitioned by the light shielding wall 207 of the second casing 20b, and is formed in the same shape in the same plane.

  With this configuration, a common plane mirror 25a (25b) can be used in a plurality of optical systems 60 (70) adjacent in the X direction. The flat mirrors 25a and 25b integrated with each other, using flat mirror fixing springs 26a and 26b as fixing members having the shape of clip springs in the gap portions of adjacent cells in the second casings 20a and 20b, It can be easily fixed from above.

  FIG. 7 is an exploded view showing the configuration of the concave mirror unit 100 of the image reading apparatus according to the second embodiment. FIG. 8 is a top view showing the first housing 10 of the concave mirror unit 100. The second embodiment includes concave mirrors 13a and 13b in which two concave mirrors belonging to the same optical system are integrated.

  The concave mirror 13a is the same as the reflective surface 130 of the concave mirror 11a (FIG. 4) described in the first embodiment and the same reflective surface of the concave mirror 12a (FIG. 4) described in the first embodiment. And a reflective surface 131.

  Similarly, the concave mirror 13b includes a reflective surface 130 identical to the reflective surface of the concave mirror 11b (FIG. 4) described in the first embodiment, and a reflective surface of the concave mirror 12b (FIG. 4) described in the first embodiment. And the same reflecting surface 131. The concave mirrors 13a and 13b are arranged at regular intervals on both sides in the Y direction with respect to the image reading position 50 and at positions shifted from each other by a half pitch in the X direction.

  As shown in FIG. 8, positioning holes (positioning means) 14 a and 14 b for fixing the concave mirrors 13 a and 13 b are provided on the upper surface of the first housing 10. The positioning holes 14a and 14b are each composed of a combination of a round hole and a long hole. The positioning holes 14a and 14b are formed by machining with a positional accuracy of several microns in order to accurately fix the concave mirrors 13a and 13b at desired positions.

  In addition, grooves 16a and 16b extending in the X direction are formed in the first casing 10, and positioning holes 15a and 15b that are round holes are formed in the grooves 16a and 16b. The grooves 16a and 16b are rotation stop grooves of the second casings 20a and 20b. The positioning holes 15a and 15b are holes for positioning the second housings 20a and 20b at desired positions. For example, long holes may be used instead of the grooves 16a and 16b.

  By using the plane mirrors 25a and 25b and the concave mirrors 13a and 13b integrated in this way, the number of parts of the optical unit 1 can be reduced. Further, the number of parts can be reduced by reducing the number of parts, and since the machining of the respective casings 10, 20a, 20b can be reduced, the assembly process can be simplified. As a result, the workability of assembling the optical unit 1 is improved, and the manufacturing cost can be reduced.

<Assembly method>
Next, a method for assembling the optical unit 1 according to the second embodiment will be described with reference to FIGS. First, as shown in FIG. 9, the concave mirrors 13 a and 13 b are fixed to the upper surface (reference surface) of the first housing 1. At this time, the positioning bosses formed on the lower surfaces of the concave mirrors 13a and 13b are fitted into the positioning holes 14a and 14b (FIG. 8) of the first housing 10 from above. By applying an adhesive on the lower surfaces of the concave mirrors 13a and 13b in advance and pressing them with a jig or the like, they can be fixed to the upper surface of the first housing 10 without play.

  Next, as shown in FIG. 10, the second casings 20 a and 20 b are attached to the upper surface of the first casing 10. At this time, by fitting positioning bosses formed on the lower surfaces of the second casings 20a and 20b into the positioning holes 15a and 15b and the grooves 16a and 16b (FIG. 8) formed in the first casing 10, The second housings 20 a and 20 b are positioned with respect to the first housing 10. Furthermore, screws 603 and 605 (FIG. 3) are screwed into the screw holes 104 and 109 (FIG. 4) through the through holes 204 and 209, and fixed to the first casing 10 of the second casings 20a and 20b.

  When the second housings 20a and 20b are attached to the upper surface of the first housing 10, the light shielding walls 207 of the second housings 20a and 20b are connected to the concave mirrors 13a and 13b fixed to the first housing 10 by one. It arrange | positions so that every one optical system (cell) may be enclosed.

  After that, as shown in FIG. 11, the plane mirrors 25a and 25b are attached to the upper surfaces of the second casings 20a and 20b. Since the plane mirrors 25a and 25b have a high likelihood of the mounting position in the in-plane direction, the positioning pins are not used and are attached to the second casings 20a and 20b on the basis of the outer shape. Further, using the flat mirror fixing springs 26a and 26b (not shown in FIG. 11) shown in FIG. 6, the flat mirrors 25a and 25b are pressed and fixed to the upper surfaces (reference surfaces) of the second casings 20a and 20b. .

  Further, the sensor substrates 25a and 25b are attached to the attachment surfaces 202 (FIG. 5) of the second housings 20a and 20b. At this time, the positioning holes 28a and 28b provided in the second housings 20a and 20b and the positioning holes 29a and 29b provided in the sensor substrate are aligned using a jig such as a positioning pin (parallel pin). Then, the optical axes of the concave mirrors 13a and 13b are made to coincide with the optical axes of the corresponding line sensors 23a and 23b.

  Next, as shown in FIG. 12, the side stand 42 is attached to the first casing 10. At this time, a positioning boss provided on the lower surface of the side stand 42 is fitted into the positioning hole 17 (FIG. 8) provided in the first housing 10 from above, and the side stand 42 is positioned with respect to the first housing 10. To do. Further, the screw 602 (see FIG. 3) is screwed into the screw hole 102 (FIG. 8), and the side stand 42 is fixed to the first casing 10. At this time, the wall portion 425 and the light shielding portion 424 of the side stand 42 come into contact with the side surfaces of the second housings 20a and 20b, and the intrusion of external light is blocked.

  Furthermore, the IR cut filter 41 is attached so as to be bridged between the side stands 42 provided on both sides in the X direction.

  Finally, as shown in FIG. 13, the lighting units 300 a and 300 b are fixed to the side stand 42 using screws 610. At this time, the illumination units 300a and 300b are positioned by fitting the positioning pins 43 (FIG. 12) on the upper surface of the side stand 42 into the positioning holes formed on the lower surfaces of the illumination units 300a and 300b.

  As described above, also in the second embodiment, the optical unit 1 can be assembled from above the first housing 10. In particular, since all the components are sequentially attached from above with reference to the reference surface (upper surface) of the first housing 10, it is easy to obtain the positional accuracy of each component. Moreover, since all components can be attached by access from above, workability is good.

  Moreover, in the assembled optical unit 1, it is divided for each optical system (cell) by the light shielding wall 207 of the second casings 20a and 20b. This prevents light from adjacent optical systems from entering each optical system.

  Furthermore, in the second embodiment, since the integrated plane mirrors 25a and 25b and the concave mirrors 13a and 13b are used, the number of assembling steps is reduced, the assembling workability is improved, and the manufacturing cost is reduced. be able to.

<Effect>
As described above, in the second embodiment of the present invention, in addition to the effects described in the first embodiment, the number of components is reduced by using the integrated flat mirrors 25a and 25b and the concave mirrors 13a and 13b. The manufacturing cost can be reduced and the manufacturing process can be simplified.

  The first and second embodiments described above can be modified as appropriate. For example, in the first and second embodiments, the example in which a plurality of optical systems are arranged on both sides of the image reading position 50 in the Y direction (sub-scanning direction) so that the positions in the X direction are shifted by a half pitch is described. The optical system may be arranged only on one side of the image reading position 50 in the Y direction.

  Further, instead of providing a positioning hole in the first housing 10 and providing a positioning boss on the lower surface of the concave mirrors 11a, 11b, 12a and 12b, a positioning boss is provided in the first housing 10 and the concave mirrors 11a, 11b and 12a. , 12b may be provided with positioning holes.

  DESCRIPTION OF SYMBOLS 10 1st housing | casing, 11a, 11b Concave mirror, 12a, 12b Concave mirror, 13a, 13b Concave mirror, 14a, 14b, 15a, 15b, 17 Positioning hole (positioning means), 16a, 16b Anti-rotation groove, 20a, 20b 2nd housing, 21a, 21b aperture, 22a, 22b plane mirror, 23a, 23b line sensor (imaging device), 24a, 24b sensor substrate, 25a, 25b plane mirror, 26a, 26b plane mirror fixing spring, 27a, 27b Window, 28a, 28b, 29a, 29b Positioning hole, 30a, 30b Light source reflecting mirror, 31a, 31b LED substrate, 32a, 32b Heat sink, 40 Platen glass, 41 IR cut filter, 42 Side stand, 43 Positioning pin , 50 image reading position, 50a, 50b light, 60 and 70 the optical system, 100 a concave mirror unit, 200a, 200b plane mirror unit, 300a, 300b lighting unit.

Claims (18)

A line sensor in which a plurality of image sensors are arranged in the main scanning direction;
An optical system in which at least one concave mirror and at least one plane mirror are alternately arranged on an optical path for guiding light from the document surface to the line sensor, and telecentric on the document surface side in the main scanning direction;
A first housing holding the concave mirror;
A second housing attached to the first housing and holding the plane mirror;
A sensor board mounted on the second housing and mounted with the line sensor;
The image reading apparatus according to claim 1, wherein the first casing has a flat plate shape, and the second casing has a deep drawing shape.   A plurality of the optical systems are arranged on both sides in the sub-scanning direction centered on the image reading position, symmetrical to each other in the sub-scanning direction and shifted by a half pitch in the main scanning direction, and arranged at equal intervals in the main scanning direction. The image reading apparatus according to claim 1.   The image reading apparatus according to claim 2, wherein in each optical system, the number of concave mirrors is one more than the number of planar mirrors. The first housing is arranged to face the document surface;
The second housing is disposed between the document surface and the first housing;
4. The image reading apparatus according to claim 2, wherein the sensor substrate is divided into two rows in the sub-scanning direction and fixed to the second casing from the document surface side. 5.   5. The image reading apparatus according to claim 1, wherein the second casing has a diaphragm on an optical path from the concave mirror to the flat mirror. 6.   6. The image reading apparatus according to claim 1, wherein the plane mirrors belonging to a plurality of optical systems adjacent to each other in the main scanning direction are integrally formed with each other.   The image reading apparatus according to claim 1, wherein the plurality of concave mirrors belonging to a common optical system and adjacent to each other in the sub-scanning direction are integrally formed with each other.   8. The image reading apparatus according to claim 1, further comprising an illumination unit for illuminating the document surface closer to the document surface than the second casing. 9.   The image reading apparatus according to claim 8, wherein a side stand is provided at an end of the second casing in the main scanning direction, and the illumination unit is supported by the side stand.   10. The image reading apparatus according to claim 1, wherein positioning means for positioning the concave mirror and the second casing is formed on the first casing. . Attaching at least one concave mirror to the first housing;
Attaching a second housing to the first housing;
Attaching at least one plane mirror to the second housing;
Attaching a sensor substrate having an image sensor to the second casing. A method for manufacturing an image reading apparatus, comprising:   12. The positioning according to claim 11, wherein in the step of attaching the concave mirror, positioning is performed by fitting a positioning boss provided in the concave mirror into a positioning hole provided in the first casing. A method for manufacturing an image reading apparatus.   In the step of attaching the second casing, positioning is performed by fitting a positioning boss provided in the second casing into a positioning hole provided in the first casing. Item 13. A method for manufacturing an image reading apparatus according to Item 11 or 12.   The method for manufacturing an image reading apparatus according to claim 11, wherein, in the step of attaching the flat mirror, the flat mirror is positioned with respect to the second casing on the basis of an outer shape. .   The step of attaching the sensor substrate includes aligning a positioning hole provided in the sensor substrate and a positioning hole provided in the second housing using a jig. 15. A method for manufacturing an image reading apparatus according to any one of items 14 to 14. further,
Attaching a side stand to the first housing;
The method for manufacturing an image reading apparatus according to claim 11, further comprising: attaching the illumination unit to the side stand.   The image according to claim 16, wherein in the step of attaching the side stand, positioning is performed by fitting a positioning boss provided in the side stand into a positioning hole provided in the first casing. A method for manufacturing a reader.   18. The positioning according to claim 16, wherein in the step of attaching the lighting unit, positioning is performed by fitting a positioning boss provided in the lighting unit into a positioning hole provided in the side stand. A method for manufacturing an image reading apparatus.

Images