JP2007300256A - Image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus capable of obtaining a suitable image by preventing a considerably greater displacement of an image forming lens so as to suppress deviation in the focus even when the temperature in the apparatus is increased/decreased. <P>SOLUTION: The image reading apparatus 1 makes light emitted to an original face and reflected therein incident on a CCD 32 being an imaging element through a lens barrel 40 provided inside with an image forming lens, and the CCD 32 reads an original image. The lens barrel 40 is placed on a fitting base 31 and supported thereon while being energized from an upper direction to a lower direction by an upper/lower direction support member 50 and while being energized in an optical axis direction by an optical axis direction support member 60. Thus, even when the lens barrel 40 and the fitting base 31 are deformed due to an increase/decrease in the temperature in the apparatus, no gap is caused between the members, rattling can be prevented, and the occurrence of a considerably large displacement of the image forming lens can be blocked. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image reading apparatus used for a copying machine, an image scanner, and the like.

  In general, an image reading apparatus used for a copying machine, an image scanner, or the like irradiates light on a document placed on a document table, and receives the reflected light to read image information on a document surface. The document table is made of transparent glass and is provided on the upper part of the apparatus main body. Inside the apparatus body below the document table, there is a light source that emits light toward the document surface, a mirror that guides the reflected light in a predetermined direction, an imaging lens, and a CCD (Charge Coupled Device). Etc. are provided.

  The focus adjustment of the image reading apparatus as described above is performed by reading a predetermined pattern image placed on the document surface. Irradiate this pattern and reflect the reflected light into the CCD, which is the image sensor, through the imaging lens, and move the imaging lens and CCD in the optical axis direction to obtain a good focus. Change the position and adjust the focus.

  In general, the imaging lens and the CCD are often held and fixed on a mounting base while adjusting the focus, and are often provided on the image reading apparatus main body via the mounting base. Examples of the image forming lens and CCD mounting structure of such an image reading device can be found in Patent Documents 1 to 4.

In the image reading apparatuses (image reading units) described in Patent Documents 1 to 3, the image forming lens (lens barrel) placed on the mounting base is perpendicular to the optical axis direction from above. An image forming lens (lens barrel) is fixed to the mounting base by screwing so as to span a holding plate extending in the direction. In the image reading unit described in Patent Document 4, the lens barrel and the mounting base (base member) are fixed with an adhesive via an intermediate holding member.
JP 2006-86984 A (page 5, FIG. 1) Japanese Patent Laid-Open No. 11-17907 (page 3, FIG. 1) Japanese Patent Laid-Open No. 6-3568 (page 3, FIG. 1) Japanese Patent Laying-Open No. 2005-37550 (page 6, FIG. 2)

  Here, the focus adjustment of the image reading apparatus is performed by opening a portion where the imaging lens and the CCD are provided at the time of assembly before product shipment. This focus adjustment is performed at the same time as the position adjustment for focusing the CCD. However, when the product is shipped, the part where the imaging lens and the CCD are provided is closed by the frame or the transparent glass of the document table. Therefore, if the image reading apparatus is operated for a long time, the temperature inside the apparatus may increase sharply. .

  Thus, as in the image reading devices (image reading units) described in Patent Documents 1 to 4, when the lens barrel is fixed to the mounting base with a pressing plate or an intermediate holding member, these members are heated. There is a risk that the apparatus may be greatly affected and expand, or the apparatus may be cooled and contracted after being shut down. If such expansion and contraction are repeated, there will be a gap between the lens barrel and the holding plate, or the screws will loosen, or the adhesive will peel off and the intermediate holding member will come off. There is a possibility of sneaking. Therefore, there arises a problem that the focus adjusted at the time of assembling the product is greatly shifted during operation.

  When the lens barrel is made of a synthetic resin material that is easily affected by heat, the above problem becomes more prominent. Further, if the lens barrel is made of a synthetic resin material, the lens barrel may be deformed or damaged due to contact with the pressing plate or the like due to repeated expansion and contraction.

  The present invention has been made in view of the above points. In an image reading apparatus that reads an original image using an imaging lens and an imaging element, even if the temperature in the apparatus rises / falls, the image is formed. An object of the present invention is to provide an image reading apparatus capable of preventing a significant displacement of a lens and suppressing a focus shift and obtaining a suitable image.

  In order to solve the above problems, the present invention provides an image reading apparatus in which light irradiated and reflected toward a document surface is incident on an image sensor through an imaging lens, and an image of the document is read by the image sensor. A lens barrel provided with the imaging lens therein, a mounting base on which the lens barrel is placed, and a vertical holding that holds the lens barrel on the mounting base while urging the lens barrel downward from above A member and an optical axis direction holding member that holds the lens barrel on the mount while urging the lens barrel in the optical axis direction are provided.

  In the image reading apparatus having the above-described configuration, the mounting base includes an engagement hole, the vertical holding member is a plate-like member, and the mounting base is provided at both ends of the lens barrel held at an intermediate position. A locking portion that engages with the engagement hole is provided.

  In the image reading apparatus having the above-described configuration, the vertical holding member has a strip-like plate shape whose length in the optical axis direction is shorter than the length in the optical axis direction of the lens barrel and extends in a direction perpendicular to the optical axis direction. In addition to being a member, the lens barrel is provided with a recess for receiving the vertical holding member.

  In the image reading apparatus having the above-described configuration, the vertical holding member extends in the optical axis direction on the upstream side and the downstream side in the optical axis direction of the contact portion with the lens barrel so as to be separated from the lens barrel. A curved protrusion is provided.

  In the image reading apparatus having the above-described configuration, the mounting base includes an opening portion on which the lens barrel is placed, and the optical axis direction holding member moves the lens barrel placed on the opening portion in the optical axis direction. The lens barrel is provided on the upstream side in the optical axis direction so as to be biased toward the downstream side.

  Further, in the image reading apparatus having the above configuration, the lens barrel is made of a synthetic resin material.

  According to the configuration of the present invention, in an image reading apparatus that reads an original image using an imaging lens and an imaging device, a lens barrel provided with an imaging lens therein, and an attachment on which the lens barrel is mounted A base, a vertical holding member that holds the lens barrel on the mounting base while biasing the lens barrel downward from above, and an optical axis direction holding member that holds the lens barrel on the mounting base while biasing the lens barrel in the optical axis direction Therefore, even if the lens barrel and the mounting base are deformed, no gap is generated between these members, and rattling can be prevented. As a result, even if the lens barrel or the mounting base expands or contracts due to an increase / decrease in the temperature in the apparatus, it is possible to prevent a large displacement of the imaging lens. Accordingly, it is possible to provide an image reading apparatus capable of suppressing a focus shift adjusted at the time of assembly before product shipment and obtaining a suitable image.

  In addition, the mounting base includes an engagement hole, the vertical holding member is a plate-like member, and a locking portion that engages the engagement hole of the mounting base at both ends of the lens barrel held at an intermediate position. Therefore, the lens barrel can be easily held on the mounting base in the vertical direction. Therefore, even when the temperature in the apparatus rises / falls, it is possible to obtain a configuration that can prevent a large displacement of the imaging lens and suppress a focus shift with a simple configuration.

  The vertical holding member is a belt-like plate-like member whose length in the optical axis direction is shorter than the optical axis length of the lens barrel and extends in a direction perpendicular to the optical axis direction. Since the concave portion for receiving the direction holding member is provided, the vertical holding member can hold the lens barrel with high accuracy in the optical axis direction in addition to the vertical direction. Thereby, the effect | action which prevents the big displacement of an imaging lens can be heightened.

  In addition, the vertical holding member includes protrusions that extend in the optical axis direction and are curved away from the lens barrel on the upstream side and the downstream side in the optical axis direction of the contact portion with the lens barrel. Even when the lens barrel and the mounting base are greatly deformed, the lens barrel can be firmly held by preventing deformation and breakage of the lens barrel due to contact with the vertical holding member. Therefore, it is possible to further improve the action of preventing a large displacement of the imaging lens.

  The mounting base includes an opening portion on which the lens barrel is placed, and the optical axis direction holding member is configured to urge the lens barrel placed on the opening portion toward the downstream side in the optical axis direction. Since the lens barrel is provided on the upstream side in the optical axis direction of the cylinder, the lens barrel can be easily positioned in the optical axis direction and held on the mounting base by pressing the lens barrel on the downstream end of the opening. it can. Therefore, even when the temperature in the apparatus rises / falls, it is possible to obtain a configuration that can prevent a large displacement of the imaging lens and suppress a focus shift with a simple configuration.

  In addition, since the lens barrel is made of a synthetic resin material, the lens barrel is easily affected by heat, but according to the present invention, even when the temperature in the apparatus rises / falls, It is possible to prevent the focus lens from being displaced by preventing a large displacement of the imaging lens. Therefore, it is possible to provide an image reading apparatus capable of obtaining a suitable image with reduced cost.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, an outline of the structure of an image reading apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic vertical sectional front view of an image reading apparatus. The image reading apparatus according to the embodiment of the present invention is designed as an image reading apparatus mounted on the upper side of a copying machine that is an image forming apparatus or a multifunction machine having functions such as a copying machine and a facsimile machine. To do.

  As shown in FIG. 1, the image reading apparatus 1 is mounted on an upper part of a copying machine or a multifunction machine that is an image forming apparatus. A main body 2 of the image reading apparatus 1 is composed of an outer cover 3 and an inner frame 4. The image reading apparatus 1 includes a document table 5 on the upper surface of the main body 2. The document table 5 is made of transparent glass, and the document is placed on the surface of the transparent glass with the reading surface (document surface) facing down.

  An optical system component for irradiating light toward the document surface is provided below the document table 5 and inside the inner frame 4 of the main body 2. The optical system components include a first optical system unit 10, a second optical system unit 20, and an imaging unit 30.

  The first optical system unit 10 includes a light source 11 and a first mirror 12. The light source 11 emits light toward the document surface. The first mirror 12 receives light reflected from the light source 11 toward the document surface and reflected by the document surface, and changes the direction at an angle of 90 degrees. The light source 11 and the first mirror 12 are fixed to a first optical system support member (not shown).

  The second optical system unit 20 includes a second mirror 21 and a third mirror 22. The second mirror 21 receives the light reflected by the first mirror 12 of the first optical system unit 10 and changes the direction at an angle of 90 degrees. The third mirror 22 receives the light reflected by the second mirror 21 and changes the direction at an angle of 90 degrees. The second mirror 21 and the third mirror 22 are fixed to a second optical system support member (not shown).

  The imaging unit 30 includes a lens barrel 40 provided with an imaging lens (not shown) in the upper part of a mounting base 31, and a CCD 32 that is an imaging element. The reflected light from the document surface reflected by the third mirror 22 of the second optical system unit 20 enters the lens barrel 40. The imaging lens of the lens barrel 40 forms an image of the reflected light on the surface of the CCD 32 provided on the downstream side of the optical path. In this way, the original image can be read by the CCD 32.

  Here, in the image reading apparatus 1 configured as described above, the imaging unit 30 is fixed to the internal frame 4 of the main body 2, but the first optical system unit 10 and the second optical system unit 20 are image information of the entire document surface. Can be reciprocated in parallel with the document surface to read the image. Therefore, a moving rail (not shown) extending in the left-right direction in FIG. 1 is provided inside the inner frame 4. The first optical system unit 10 and the second optical system unit 20 can move along the rails and read image information on the entire document surface.

  Subsequently, the configuration of the imaging unit 30 of the image reading apparatus 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is a perspective view of the imaging unit, and FIG. 3 is a front view of a partial vertical section of the imaging unit. The arrows in the figure indicate the incident direction (optical axis direction) of the reflected light from the document surface.

  As shown in FIG. 2, the imaging unit 30 includes a mounting base 31 serving as a base thereof. The mounting base 31 includes an engaging portion 33 with the inner frame 4 (see FIG. 1) of the main body 2 at the lower part thereof. The engaging portion 33 is provided at three locations on the front side, the back side, and the upstream side in the optical axis direction of the mounting base 31. The mounting base 31 is provided with a plurality of round holes 31a. These round holes 31 a are used for position and angle adjustment when the imaging unit 30 is attached to the inner frame 4. The position in the optical axis direction and the angle of the optical axis are adjusted by selecting one of the plurality of round holes 31a and engaging with a pin (not shown) provided in the inner frame 4.

  A lens barrel 40 is placed on the upper surface of the mounting base 31. The lens barrel 40 is made of a synthetic resin material and includes an imaging lens (not shown) therein. The lens barrel 40 is attached so as to receive reflected light from the document surface and guide it to the CCD 32 provided on the downstream side of the optical path (see FIG. 3).

  As shown in FIG. 3, a CCD 32 is provided on the downstream side of the optical path with respect to the lens barrel 40 placed on the upper surface of the mount 31. The CCD 32 is fixed to the control board 34. A cover member 35 that covers the periphery of the optical path is provided between the lens barrel 40 and the CCD 32.

  Next, a detailed configuration of the lens barrel 40 portion of the imaging unit 30 will be described with reference to FIGS. 4 to 7 in addition to FIGS. 2 and 3. 4 is an enlarged perspective view of the lens barrel portion of the imaging unit, FIG. 5 is an enlarged front view of the vertical section of the concave portion of the lens barrel, FIG. 6 is a perspective view of the vertical holding member of the lens barrel, and FIG. It is a perspective view of the optical axis direction holding member of a lens-barrel.

  As shown in FIG. 2, the mounting base 31 of the imaging unit 30 includes an opening 36 at the place where the lens barrel 40 is placed. The opening 36 is large enough to receive the lens barrel 40 in the optical axis direction, and slightly smaller than the size of the lens barrel 40 in the direction perpendicular to the optical axis direction. Therefore, when the lens barrel 40 is placed in the opening 36, the lens barrel 40 can be supported without dropping downward.

  As shown in FIGS. 2 to 4, a vertical holding member 50 and an optical axis direction holding member 60 are provided for the lens barrel 40 placed on the mounting base 31 as described above.

  As shown in FIGS. 4 and 6, the vertical holding member 50 has a strip shape extending in a direction perpendicular to the optical axis direction and having an optical axis direction length shorter than the optical axis direction length of the lens barrel 40. It is a plate-like member. The vertical holding member 50 is made of an elastic material and is bent into a gate shape. Locking portions 51 that engage with the mounting base 31 are provided at both ends of the vertical holding member 50 that extends in a band shape. Further, a protrusion 52 is provided at an intermediate portion of the vertical holding member 50 so as to be curved upwardly on the upstream side and the downstream side in the optical axis direction.

  As shown in FIGS. 3 to 5, the vertical holding member 50 is attached so as to be received in a recess 41 provided in the lens barrel lens 40. The concave portion 41 is provided at a substantially central portion in the optical axis direction of the lens barrel 40 and extends in the circumferential direction. As shown in FIGS. 2 and 4, the vertical holding member 50 is provided so as to span from above the lens barrel 40 in a direction perpendicular to the optical axis direction. The vertical holding member 50 is in contact with the lens barrel 40 at an intermediate position thereof, and is curved away from the lens barrel 40 at the upstream and downstream edges of the concave portion 41 of the barrel lens 40 in the optical axis direction. The protruding portion 52 is hooked (see FIG. 5).

  As shown in FIG. 2, two engagement holes 37 are provided at positions corresponding to the vertical holding member 50 on the front side and the back side of the opening 36 of the mounting base 31. When the vertical holding member 50 is attached to the mounting base 31 while holding the lens barrel 40, both ends of the vertical holding member 50 having a gate shape are elastically deformed so as to be separated from each other, and The stopper 51 is attached so as to be hooked in the engagement hole 37 of the attachment base 31. In this way, the vertical holding member 50 holds the lens barrel 40 on the mounting base 31 while urging the lens barrel 40 downward from above.

  On the other hand, as shown in FIGS. 4 and 7, the optical axis direction holding member 60 is composed of a plate member having elasticity, and is attached to a mounting portion 61 for fixing to the mounting base 31 and is bent into a dogleg shape. And an urging portion 62.

  As shown in FIG. 2, the optical axis direction holding member 60 is provided on the upstream side of the lens barrel 40 in the optical axis direction. The optical axis direction holding member 60 is configured so that the dog-shaped biasing portion 62 is accommodated in a gap formed on the upstream side in the optical axis direction of the opening portion 36 of the mounting base 31 on which the lens barrel lens 40 is placed. The mounting portion 61 is fixed to the mounting base 31. As shown in FIGS. 3 and 4, the urging portion 62 of the optical axis direction holding member 60 abuts on the edge portion of the upstream end portion of the lens barrel 40, and the lens barrel 40 is moved in the optical axis direction. It is energized downstream. In this way, the optical axis direction holding member 60 and the lens barrel 40 are held on the mounting base 31 while being urged in the optical axis direction.

  As described above, in the image reading apparatus 1 that reads an original image using the imaging lens and the CCD 32 that is an imaging device, the lens barrel 40 provided with the imaging lens therein, and the lens barrel 40 are mounted. A mounting base 31, a vertical holding member 50 that holds the lens barrel 40 on the mounting base 31 while biasing the lens barrel 40 downward from above, and a mounting base that biases the lens barrel 40 in the optical axis direction. Since there is an optical axis direction holding member 60 held on 31, even if the lens barrel 40 or the mounting base 31 is deformed, there is no gap between these members, and rattling is prevented. can do. Thereby, even if the lens barrel 40 or the mounting base 31 expands or contracts due to increase / decrease of the internal temperature of the apparatus, it is possible to prevent a large displacement of the imaging lens. . Therefore, it is possible to provide the image reading apparatus 1 that can suppress a focus shift adjusted at the time of assembly before product shipment and can obtain a suitable image.

  The mounting base 31 includes an engagement hole 37, and the vertical holding member 50 is a plate-like member, and the engagement hole 37 of the mounting base 31 is provided at both ends of the lens barrel 40 held at an intermediate position. Since the engaging portion 51 to be engaged is provided, the lens barrel 40 can be easily held on the mounting base 31 in the vertical direction. Therefore, even when the temperature in the apparatus rises / falls, it is possible to obtain a configuration that can prevent a large displacement of the imaging lens and suppress a focus shift with a simple configuration.

  The vertical holding member 50 is a belt-like plate-like member whose length in the optical axis direction is shorter than the length in the optical axis direction of the lens barrel 40 and extends in a direction perpendicular to the optical axis direction. 40 has a concave portion 41 for receiving the vertical holding member 50, so that the vertical holding member 50 can hold the lens barrel 40 with high accuracy in the optical axis direction in addition to the vertical direction. is there. Thereby, the effect | action which prevents the big displacement of an imaging lens can be heightened.

  The vertical holding member 50 includes projecting portions 52 extending in the optical axis direction and curved so as to be away from the lens barrel 40 on the upstream side and the downstream side in the optical axis direction of the contact portion with the lens barrel 40. Therefore, even if the lens barrel 40 or the mounting base is greatly deformed, the lens barrel 40 is prevented from being deformed or damaged due to contact with the vertical holding member 50, and the lens barrel 40 is firmly attached. Can be held. Therefore, it is possible to further improve the action of preventing a large displacement of the imaging lens.

  Further, the mounting base 31 includes an opening 36 on which the lens barrel 40 is placed, and the optical axis direction holding member 60 attaches the lens barrel 40 placed on the opening 36 toward the downstream side in the optical axis direction. Since the lens barrel 40 is provided upstream of the lens barrel 40 in the optical axis direction, the lens barrel 40 can be easily positioned in the optical axis direction by pressing the lens barrel 40 against the downstream end of the opening 36. However, it can be held on the mounting base 31. Therefore, even when the temperature in the apparatus rises / falls, it is possible to obtain a configuration that can prevent a large displacement of the imaging lens and suppress a focus shift with a simple configuration.

  In addition, since the lens barrel 40 is made of a synthetic resin material, the lens barrel 40 is easily affected by heat. However, according to the present invention, even when the temperature in the apparatus rises / falls, image formation is performed. It is possible to prevent the lens from being largely displaced and suppress the focus shift. Therefore, it is possible to provide the image reading apparatus 1 capable of obtaining a suitable image with reduced cost.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used in all image reading apparatuses using a lens barrel.

1 is a schematic vertical sectional front view of an image reading apparatus according to an embodiment of the present invention. It is a perspective view of the imaging unit of the image reading apparatus shown in FIG. FIG. 3 is a partial sectional front view of the imaging unit shown in FIG. 2. FIG. 3 is an enlarged perspective view of a lens barrel portion of the imaging unit shown in FIG. 2. It is a vertical cross-section part enlarged front view of the recessed part of the lens-barrel shown in FIG. It is a perspective view of the up-down direction holding member of the lens barrel shown in FIG. It is a perspective view of the optical axis direction holding member of the lens barrel shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image reader 2 Main body 4 Internal frame 10 1st optical system unit 20 2nd optical system unit 30 Imaging unit 31 Mounting stand 32 CCD (imaging element)
36 Opening 37 Engagement hole 40 Lens barrel 41 Recess 50 Vertical holding member 51 Locking portion 52 Projection portion 60 Optical axis direction holding member 61 Mounting portion 62 Energizing portion

Claims (6)

In an image reading apparatus in which light irradiated and reflected toward a document surface is incident on an image sensor through an imaging lens, and an image of the document is read by the image sensor.
A lens barrel provided with the imaging lens therein, a mounting base on which the lens barrel is placed, and a vertical holding that holds the lens barrel on the mounting base while urging the lens barrel downward from above An image reading apparatus comprising: a member; and an optical axis direction holding member that holds the lens barrel on the mount while urging the lens barrel in the optical axis direction.   The mounting base is provided with an engagement hole, and the vertical holding member is a plate-like member, and is engaged with the engagement hole of the mounting base at both ends of the lens barrel held at an intermediate position. The image reading apparatus according to claim 1, further comprising a stop portion.   The vertical holding member is a strip-shaped plate-like member whose length in the optical axis direction is shorter than the length in the optical axis direction of the lens barrel and extends in a direction perpendicular to the optical axis direction. The image reading apparatus according to claim 1, further comprising a concave portion that receives the direction holding member.   The vertical holding member includes protrusions that extend in the optical axis direction and are curved away from the lens barrel on the upstream side and the downstream side in the optical axis direction of the contact portion with the lens barrel. The image reading apparatus according to claim 3.   The mount includes an opening on which the lens barrel is placed, and the optical axis direction holding member biases the lens barrel placed on the opening toward the downstream side in the optical axis direction. The image reading apparatus according to claim 1, wherein the image reading apparatus is provided on the upstream side of the lens barrel in the optical axis direction.   The image reading apparatus according to claim 1, wherein the lens barrel is made of a synthetic resin material.

Images