JP6668988B2 - Image reading optical system and image reading device - Google Patents

Description

  The present invention relates to an image reading optical system and an image reading device.

  Patent Document 1 discloses that image information on a document surface is imaged on a line sensor extending in the main scanning direction, and the relative position between the document surface and the line sensor is changed in the sub-scanning direction, and the image information is changed by the line sensor. An imaging optical system for image reading for reading, wherein an off-axial reflecting surface for deflecting the reference axis light beam in a clockwise direction is a minus deflection surface, and an off-axial reflecting surface for deflecting the reference axis light beam in a counterclockwise direction. When defined as a plus deflection surface, the imaging optical system is composed of two off-axial reflection surfaces, and the two off-axial reflection surfaces are a plus deflection surface, a minus deflection surface or a minus deflection surface, a plus deflection surface, Are arranged in the optical path of the imaging optical system in this order.

Patent Literature 2 discloses that a convex mirror having negative power that reflects light from an object, a concave mirror having positive power that reflects light from a convex mirror, and reflection from a convex mirror and a concave mirror from the object side. The convex mirror and the concave mirror form a coaxial system. When the incident angle is ω and the aperture ratio is F (F number), sinω> (2 ^{1 /} An off-axis reflecting optical system that satisfies the condition of ( ² + 1) / 2F is disclosed.

Japanese Patent No. 4817773 JP 2003-005073 A

  The present invention is directed to a case where a diaphragm is arranged on a bent optical path, compared with a case where each diaphragm member for regulating in a plurality of directions uses a reflection imaging optical system having a diaphragm arranged in the same place. It is an object of the present invention to provide an image reading optical system and an image reading apparatus that can make a bending angle of an optical path deep.

  In order to achieve the above object, the image reading optical system according to claim 1, wherein an image reading unit in which a plurality of reading elements are arranged in a first direction, and reflected light in which irradiation light from a light source is reflected by a reading target. A first reflective optical system that reflects light, a first stop that regulates light reflected by the first reflective optical system in the first direction, and a light that is reflected by the first reflective optical system. Of the reflected light, the second reflection type optical system that reflects the light that has passed through the first stop and guides the light to the image reading unit, and the light that enters through the first stop member and the second stop member. A second diaphragm that regulates the light in a second direction intersecting the first direction, wherein the first diaphragm member and the second diaphragm member are positioned at different folded light positions on an optical path. A second stop for restricting light beams on the road from different sides in the second direction. That.

  According to a second aspect of the present invention, in the first aspect, at least one of the first aperture member and the second aperture member has the same folded light as the first aperture on the optical path. It is arranged at the position of.

  According to a third aspect of the present invention, in the second aspect, at least one of the first aperture member and the second aperture member is integrated with the first aperture. is there.

  According to a fourth aspect of the present invention, in the third aspect of the invention, the first stop member is formed of a plate-like member, and the light incident on one side of the plate-like member is transmitted in the second direction. The second diaphragm member is integrated with the first diaphragm, and transmits light incident on a side of the concave portion provided in the first diaphragm along the first direction along the second direction. Is regulated in the direction of.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the first diaphragm rises from an end of the concave portion, is arranged in the first direction, and has the first reflection. And two stop pieces having oblique sides facing the light reflected by the mold optical system, and restricting the light reflected by the first reflection type optical system by the two stop pieces in the first direction. Things.

  According to a sixth aspect of the present invention, in the third aspect of the invention, the first aperture member and the second aperture member are formed continuously with the first aperture. The first diaphragm and the second diaphragm are integrated to form an integral diaphragm, and the integral diaphragm is formed of a plate-shaped member having a rectangular recess opening in the second direction. The first aperture is formed by two sides of the concave portion along the second direction, and the first aperture of the concave portion along the side of the concave portion along the first direction and the outer periphery of the integral aperture. The second aperture is constituted by a side.

  The invention according to claim 7 is the invention according to claim 3, wherein the first diaphragm member and the second diaphragm member are formed continuously with the first diaphragm. A first diaphragm and the second diaphragm are integrated to form an integral diaphragm, and the integral diaphragm is a rectangle having two sides along the second direction in which the first diaphragm is formed. A first opening having a shape, and a second opening and a third opening provided continuously on both sides in the second direction with respect to the first opening, wherein the second opening and the third opening are provided. Side of the opening along the first direction on the opposite side to the first opening, and along the first direction on the side of the third opening opposite to the first opening. A second aperture and a third aperture each of which defines the second stop by a side.

  In order to achieve the above object, an image reading apparatus according to claim 8 irradiates a reading target with light, an image reading optical system according to any one of claims 1 to 7, Is included.

  According to the first and eighth aspects of the present invention, each of the diaphragm members for regulating in a plurality of directions is bent more than in a case where a reflective imaging optical system having a diaphragm arranged in the same place is used. When the stop is arranged on the optical path, the image reading optical system and the image reading apparatus that can increase the bending angle of the optical path are provided.

  According to the second aspect of the present invention, both the first aperture member and the second aperture member are disposed at different positions of the reflected light from the first aperture, and the first aperture member and the second aperture member are compared with each other. The effect is obtained that a part of the second stop is arranged close to the second stop.

  According to the third aspect of the invention, compared to a case where both the first aperture member and the second aperture member are separate from the first aperture member, the production of the aperture is further simplified. The effect is obtained.

  According to the invention described in claim 4, the light to be regulated and the first diaphragm member are compared with the case where both the first diaphragm member and the second diaphragm member are integrated with the first diaphragm. And the restriction on the arrangement relationship with the second aperture member is eased.

  According to the fifth aspect of the present invention, an effect is obtained in that the depth of focus is increased as compared with the case where the light reflected by the first reflective optical system is regulated in the first direction by the side of the concave portion. Can be

  According to the sixth aspect of the present invention, there is obtained an effect that the shape of the integral stop is simplified as compared with the case where the second stop is constituted by the opening provided in the integral stop. .

  According to the seventh aspect of the present invention, the first aperture stop and the second aperture stop are more freely arranged relative to each other as compared with the case where the second aperture stop is formed by the recess provided in the integral stop. The effect of increasing the degree is obtained.

1 is a schematic cross-sectional view illustrating an example of a configuration of an image reading device according to an embodiment. FIG. 1 is a schematic sectional view illustrating an example of a configuration of an image reading optical system according to a first embodiment. FIG. 3 is a diagram illustrating a shape of a diaphragm according to the first embodiment. 2A and 2B are a side view and a plan view illustrating an example of a configuration of an image reading optical system according to the first embodiment. FIG. 11 is a diagram illustrating an example of an image reading optical system and an aperture shape according to a second embodiment. FIG. 14 is a schematic sectional view illustrating an example of a configuration of an image reading optical system according to a third embodiment. It is a figure explaining the shape of the stop concerning a 3rd embodiment. It is a side view and a top view showing an example of the composition of the image reading optical system concerning a 3rd embodiment. FIG. 14 is a diagram illustrating another example of the shape and arrangement of the stop of the image reading optical system according to the third embodiment. FIG. 6 is a schematic sectional view illustrating a configuration of an image reading optical system according to a comparative example. It is a figure explaining separation of the diaphragm member concerning an embodiment.

  Hereinafter, an example of an embodiment for carrying out the present invention will be described in detail with reference to the drawings.

  The image reading device 12 according to the present embodiment will be described with reference to FIG. FIG. 1 shows a schematic configuration of the image reading device 12. The image reading device 12 is provided, for example, in association with the image forming apparatus, and is used for reading a document or the like (a reading target). As shown in FIG. 1, the image reading device 12 includes an automatic document feeder 50 and an image reading processing unit 52 that reads an image formed on the surface of a document.

  Automatic document feeder 50 according to the present embodiment includes a document table 60 on which a document is placed, a document conveyance path 61 for conveying the document, and a discharge table 62 for discharging the document after reading the image. It is composed of

  The document conveying path 61 is formed in a U-shape, and around the document conveying path 61, a paper sending roll 63, a sending roll 64, a pre-alignment roll 65, a positioning roll 66, a platen roll 67, an out roll 68, And a discharge roll 69. The paper feed roll 63 descends during document feeding, and picks up a document placed on the document table 60. The delivery roll 64 supplies the uppermost document among the documents sent from the paper delivery roll 63 to the inside. The pre-positioning roll 65 temporarily stops the document sent from the sending roll 64 and corrects skew. The alignment roll 66 temporarily stops the original sent from the pre-alignment roll 65 and adjusts the reading timing. The platen roll 67 causes a document passing through the document transport path 61 to face a platen glass 70 described later. The out roll 68 and the discharge roll 69 discharge the read document to the discharge table 62.

  The image reading device 12 has a function of reading the surface of a document sent from the document table 60 by the automatic document feeder 50 and a function of reading the surface of a document placed on a platen glass 70 described later. I have.

A document for reading an image is placed on a surface of the housing 75 of the image reading processing unit 52 facing the automatic document feeder 50. When reading the document being conveyed by the automatic document feeder 50, light is applied to the document. A platen glass 70 serving as an opening for irradiation is provided.
Further, inside the housing 75, the document can be moved in the document conveyance direction (Y-axis direction in FIG. 1), and the image is read at the reading position M of the platen glass 70 while being stopped, or the entire platen glass 70 is read. A reading unit (carriage) 76 that reads an image while scanning is provided.

  The reading unit 76 includes an illumination unit 80 (light source), an imaging unit 87, and a sensor 88 (image reading unit). The image reading optical system 86 according to the present embodiment includes the image forming unit 87 and the sensor 88.

  As an example, the lighting unit 80 is configured by arranging a plurality of white light emitting diodes (LEDs) as light sources. The diffuse reflection member 82 is a member that reflects the light emitted from the illumination unit 80 while diffusing the light toward the document surface. The mirror 83, the mirror 84, and the mirror 85 are members that guide the reflected light L obtained from the document surface to the image reading optical system 86.

  The image forming section 87 has a function of shaping the light flux (optical image) of the reflected light L obtained from the document surface into a shape suitable for light reception by the sensor 88. The imaging unit 87 may include an imaging lens (not shown) for optically reducing an optical image obtained from the document surface. The details of the imaging unit 87 will be described later.

  The sensor 88 has a function of photoelectrically converting an optical image obtained from the image forming unit 87 to generate each color signal (image signal) of red (R), green (G), and blue (B). The sensor 88 has a configuration in which, for example, one-dimensional line sensors extending in the X-axis direction for each color of R, G, and B are arranged in three rows in the Z-axis direction. As an example, a CCD image sensor is used. . In other words, the sensor 88 is configured such that imaging elements (reading elements) are arranged in the X-axis direction.

  Next, a procedure for reading an image in the image reading apparatus 12 according to the present embodiment will be described.

  When reading a document placed on the platen glass 70 in the image reading device 12, a control unit (not shown) moves the reading unit 76 in the scanning direction (the direction of arrow C in FIG. 1). The control unit also causes the illumination unit 80 of the reading unit 76 to emit light and irradiate the document surface. By the irradiation, the reflected light L from the document is guided to the image reading optical system 86 via the mirror 83, the mirror 84, and the mirror 85. The light guided to the image reading optical system 86 forms an image on the light receiving surface of the sensor 88. The sensor 88 reads one line for each of R, G, and B colors substantially simultaneously. Then, the reading in the line direction is executed by scanning over the entire size of the original, thereby reading the original of one page.

  On the other hand, when the image reading device 12 reads a document placed on the document table 60, the control unit (not shown) moves the document placed on the document table 60 to the reading position M of the platen glass 70 along the document transport path 61. To be transported. At this time, the reading unit 76 is positioned in a stopped state at the position indicated by the solid line in FIG. The control unit also causes the illumination unit 80 to emit light and irradiate the original surface. As a result, the reflected light L of the document closely attached to the platen glass 70 by the platen roll 67 is guided to the image reading optical system 86 via the mirror 83, the mirror 84, and the mirror 85. The light guided to the image reading optical system 86 forms an image on the light receiving surface of the sensor 88. The sensor 88 reads one line for each of R, G, and B colors substantially simultaneously. Then, one page of the document is read by passing the entire document through the reading position M of the platen glass 70.

  By the way, as an optical system for shaping the reflected light L obtained from the document surface into a shape suitable for light reception by the sensor 88, a plurality of reflections having power (strength of bending light) in a predetermined direction are provided. There is a case where an image reading optical system combining a mold optical system is used. In an image reading optical system in which a plurality of reflection optical systems are combined, a folded optical path is inevitably generated. On the other hand, in the image reading optical system, an aperture is used for adjusting light quantity, adjusting MTF (Modulated Transfer Function: transfer function of the optical system), increasing the depth of focus, and the like. It is necessary to narrow down in both the longitudinal direction of the sensor (the direction in which the imaging elements are arranged, the X-axis direction in FIG. 1) and the short direction (the direction orthogonal to the direction in which the imaging elements are arranged, the Z-axis direction in FIG. 1). Considering the case where there are two reflective optical systems, the stop in this case is usually disposed between the two reflective optical systems. Hereinafter, the reflection type optical system may be referred to as an “imaging mirror”.

  FIG. 10 shows an image reading optical system 200 according to a comparative example, which is an example of the above-described image reading optical system. As shown in FIG. 10, the image reading optical system 200 includes an imaging mirror 100, an imaging mirror 102, an aperture 104, and a sensor 106.

  Here, in the case where the image reading optical system 200 is to be reduced in size especially by shortening in the short direction, or in the case where the accuracy is to be improved, that is, the angle θ1 or the angle θ2 in FIG. 10 is to be reduced. In this case, the light incident on the imaging mirror 100, that is, the reflected light L obtained on the original surface may be kicked in the short direction by the stop 104 (see the dotted circle in FIG. 10). This is because the diaphragm 104 is usually manufactured by providing a plate-shaped member with an opening such as a circle, and thus requires a certain size in both the longitudinal direction and the lateral direction.

  Therefore, in the present embodiment, the stop for restricting the light flux of the reflected light L is divided into a first stop for stopping in the longitudinal direction and a second stop for stopping in the short direction, and the degree of freedom in each arrangement is increased. I decided to give it. At that time, the first aperture that is narrowed in the longitudinal direction is preferentially arranged at an appropriate position. This is because, in the present embodiment, the sensor 88 is a one-dimensional line sensor extended in the X-axis direction, and the angle of view (viewing angle) in the longitudinal direction is large. On the other hand, the second stop, which is narrowed in the short direction, has a small angle of view, and is freely arranged in consideration of a space or the like of the image reading apparatus without being affected by the first stop position. As a result, the image reading optical system is contracted in the short direction while securing the function of the diaphragm in the longitudinal direction and the short direction, so that the image reading apparatus is further downsized.

  Referring to FIG. 11, the separation of the aperture according to the present embodiment will be described in more detail. FIG. 11A shows a general diaphragm 110 that regulates the light flux of the reflected light L. As shown in FIG. 11A, the stop 110 has an opening 112 having two edges (ends, sides) on the left, right, up and down, and regulates the luminous flux of the reflected light L by the opening 112.

  FIG. 11B shows a state where the diaphragm 110 is cut at the opening 112 and divided into four diaphragm members. That is, the diaphragm 110 is divided into diaphragm members 110a and 110b for regulating in the longitudinal direction and diaphragm members 110c and 110d for regulating in the lateral direction. The end (edge, side) E1 of the stop member 110a and the end E2 of the stop member 110b form an end pair for restricting the light flux of the reflected light L in the longitudinal direction, and the end E3 of the stop member 110c and the stop E3. The end portion E4 of the member 110d forms a pair of end portions that regulate the light flux of the reflected light L in the short direction. In other words, the ends E1 to E4 are connected in the general stop 110, but in the stop according to the present embodiment, a part of the ends E1 to E4 is separated from the other ends. Each of the aperture members 110a to 110d is disposed. In the following, the pair of ends of the stop that narrows the light flux of the reflected light L in the longitudinal direction is referred to as “end E1” and “end E2”, and the end of the stop that narrows the light flux of the reflected light L in the short direction. The pair of parts may be referred to as “end E3” and “end E4”. In addition, the stop that regulates the light flux of the reflected light L in the longitudinal direction may be referred to as a “first stop”, and the stop that regulates the light flux in the lateral direction may be referred to as a “second stop”. In this specification, “regulating the light beam in the longitudinal direction” means preventing the light beam from spreading in the longitudinal direction.

  In the present embodiment, as described above, the aperture members 110a and 110b are preferentially arranged at appropriate positions, and the aperture members 110c and 110d take into account the size of the image reading optical system or the image reading device. And place it.

[First Embodiment]
FIG. 2 shows an image reading optical system 86 according to the present embodiment. As shown in FIG. 2, the image reading optical system 86 includes an image forming section 87 and a sensor 88. The imaging unit 87 includes an imaging mirror 90, an imaging mirror 92, and a stop 94.

  The image forming mirror 90 according to the present embodiment is a reflecting mirror (in the present embodiment, a concave mirror) that collects the reflected light L obtained from the document surface and reflects the light toward the image forming mirror 92. The image forming mirror 92 according to the present embodiment is a reflecting mirror (in the present embodiment, a concave mirror) that reflects the light reflected by the image forming mirror 90 toward the sensor 88. The diaphragm 94 disposed between the imaging mirror 90 and the imaging mirror 92 has a diaphragm member that narrows the light reflected by the imaging mirror 90 in the longitudinal direction and a diaphragm member that narrows the light reflected in the transverse direction at the same place. This is an example of arrangement. In other words, the stop 94 according to the present embodiment includes the recess 20 so that the light beam of the reflected light L is regulated in both the longitudinal direction and the short direction by a single stop (integrated stop). In the following, each of the light from the light source to the imaging mirror 90, the light from the imaging mirror 90 to the imaging mirror 92, and the light from the imaging mirror 92 to the sensor 88 may be referred to as "folded light". .

  Referring to FIG. 3, stop 94 according to the present embodiment will be described in more detail. As shown in FIG. 3, the stop 94 includes ends E1 and E2, which are pairs of ends that narrows the light flux of the reflected light L in the longitudinal direction, and ends that are a pair of ends that narrows the light flux of the reflected light L in the short direction. E3 and E4 (first aperture member, second aperture member) are provided. The ends E1 and E2 are arranged along the longitudinal direction, and the gap between the end E1 and the end E2 causes the reflected light L at the position of the folded light between the imaging mirror 90 and the imaging mirror 92 to return. The light flux is regulated in the longitudinal direction. On the other hand, the ends E3 and E4 are also arranged in the short direction, but have no gap therebetween. The provision of the recess 20 opens one end of the diaphragm 94 in the short side direction on the side opposite to the side on which the end E3 is disposed (no restriction member is disposed).

  Here, as shown in FIG. 2, in the light flux of the reflected light L, the uppermost ray in the Z-axis direction (that is, the shorter direction) is Lu, and the lowermost ray is Ld. At this time, the end E3 of the stop 94 restricts a light beam (hereinafter, referred to as a “lower light beam”) within a predetermined range from the light ray Ld at a position P1 indicated by a dotted circle in FIG. Restricts a light flux in a predetermined range (hereinafter, “upper light flux”) from the light beam Lu at a position P2 indicated by a dotted circle in FIG.

  Here, the position P1 is a position with respect to the light beam incident on the image forming mirror 90, and the position P2 is a light beam reflected by the image forming mirror 90. In this sense, the end portions E3 and E4 are different on the optical path. At the position of the returning light, the light flux on the optical path is regulated from different sides. That is, since the end portions E3 and E4 regulate different positions of the folded light (upper light beam or lower light beam), in that sense, the end portions E3 and E4 are arranged at different positions. I have.

  On the other hand, in the stop 94, the ends E3 and E4 are arranged on the same member as the ends E1 and E2. In that sense, in the stop 94, the second stop is arranged at the same place as the first stop. However, the “same place” in the present embodiment is not limited to arranging the end E3 or the end E4 on the same member as the ends E1 and E2, but at the same folded light position on the optical path. , End E3 or end E4 is separated from ends E1 and E2. In other words, in other words, the end 94 of the second stop is connected to the ends E1 and E2, but the end E3 is separated from the ends E1 and E2. .

  The image reading optical system 86 will be described in more detail with reference to FIG. 4A is a side view of the image reading optical system 86 shown in FIG. 2 as viewed from the + Y direction, and FIG. 4B is a view of the image reading optical system 86 shown in FIG. 2 as viewed from the −Z direction. It is a top view.

  As shown in FIG. 4, the reflected light L is reflected by the imaging mirror 90, and the reflected light flux is regulated in the longitudinal direction (X-axis direction) at the ends E1 and E2 in the concave portion 20 of the stop 94. On the other hand, in the stop 94, the positions to be stopped in the short direction (Z-axis direction) are separated. That is, in the light flux of the reflected light L, the lower light flux is regulated first by the end E3, and then the upper light flux is regulated by the end E4. Further, the regulation by the end portion E3 and the regulation by the end portion E4 are performed at different positions of the reflected light. In other words, the ends E3 and E4 are gathered on one side of the aperture member and need not be provided on the other side of the aperture member, so that the other side of the aperture 94 is open. For this reason, the image reading optical system 86 according to the present embodiment is smaller in the lateral direction than the image reading optical system 200 according to the comparative example.

  In the above-described embodiment, the mode in which the lower light beam is regulated by the end portion E3 has been described as an example. However, the present invention is not limited to this, and the end portion E3 is located at the position of the folded light between the imaging mirror 92 and the sensor 88. The upper light beam may be regulated by E3. In this case, in the stop 94 shown in FIG. 3, the concave portion 20 having an opening on the right side when viewed from the front in the drawing may have an opening on the left side. As a result, the end E4 is changed so as to regulate the lower luminous flux.

[Second embodiment]
An image reading optical system 86A according to the present embodiment will be described with reference to FIG. The image reading apparatus according to the present embodiment is obtained by replacing the image reading optical system 86 of the image reading apparatus 12 according to the above embodiment with an image reading optical system 86A. Since it is the same as the reading device 12, FIG. 1 will be referred to as necessary, and illustration of the image reading device will be omitted. Further, the image reading optical system 86A is a form in which the stop 94 of the image reading optical system 86 according to the above embodiment is replaced with a stop 96, and the configuration other than the stop 96 is the same as the image reading optical system 86. The same reference numerals are given to the components, and the detailed description is omitted.

  As shown in FIG. 5A, the image reading optical system 86A includes an image forming section 87A and a sensor 88. Further, the imaging unit 87A includes an imaging mirror 90, an imaging mirror 92, and a stop 96.

  FIG. 5B is a diagram illustrating details of the stop 96. As shown in FIG. 5B, the stop 96 has an opening 22 having a substantially letter H shape. The openings 22 are located at positions shown in FIG. 5B, respectively, at ends E1 and E2 for regulating the luminous flux of the reflected light L in the longitudinal direction, and at ends E3 and E3 for regulating the luminous flux of the reflected light L in the lateral direction. E4 is provided. That is, the ends E1 and E2 constitute a first stop, and the ends E3 and E4 constitute a second stop.

  The light flux of the reflected light L is restricted in the longitudinal direction by the ends E1 and E2 at the position of the folded light between the imaging mirror 90 and the imaging mirror 92. On the other hand, the regulation of the light flux of the reflected light L in the lateral direction is performed as follows. That is, the upper light beam including the light beam Lu is regulated by the end E3 at the position P3 shown in FIG. On the other hand, the lower luminous flux including the light ray Ld is restricted by the end E4 at the position P4 shown in FIG.

  The diaphragm 96 is in the form of an “integrated diaphragm” in which the first diaphragm and the second diaphragm are integrally formed, that is, the diaphragm 96 has the same diaphragm member as the first diaphragm as the second diaphragm. It is a form arranged in a place. In other words, each of the end portions E3 and E4 is disposed separately from the end portions E1 and E2. According to the stop 96, the stop member for controlling the upper light beam is disposed further above the upper light beam, and the stop member for controlling the lower light beam is positioned further below the lower light beam. The light flux of the reflected light L is not kicked at the end on the outer periphery. For this reason, since the image forming part 87A according to the present embodiment is contracted in the short direction, the image reading optical system 86A according to the present embodiment is shorter than the image reading optical system 200 according to the comparative example. The size is reduced depending on the direction.

[Third Embodiment]
The image reading optical system 86B according to the present embodiment will be described with reference to FIGS.
The image reading apparatus according to the present embodiment is obtained by replacing the image reading optical system 86 of the image reading apparatus 12 according to the above-described embodiment with an image reading optical system 86B. Since it is the same as the reading device 12, FIG. 1 will be referred to as necessary, and illustration of the image reading device will be omitted. Further, the image reading optical system 86B is a form in which the stop 94 of the image reading optical system 86 according to the above embodiment is replaced with a stop 98, and the configuration other than the stop 98 is the same as the image reading optical system 86. The same reference numerals are given to the components, and the detailed description is omitted.

  FIG. 6 shows an image reading optical system 86B according to the present embodiment. As shown in FIG. 6, the image reading optical system 86B includes an image forming section 87B and a sensor 88. The imaging unit 87B includes an imaging mirror 90, an imaging mirror 92, and a stop 98. The diaphragm 98 is configured to include two diaphragm members that restrict the light flux on the optical path from different sides in the short direction, that is, a diaphragm member 98-1 and a diaphragm member 98-2.

  Referring to FIG. 7, the stop 98 will be described in more detail. As shown in FIG. 7A, the aperture member 98-1 is configured to include a plate-shaped member 98c, and an aperture piece 98a and an aperture piece 98b rising from the plate-shaped member 98c and having a substantially right triangle shape. I have. Further, the aperture member 98-1 includes a concave portion 24 having an open portion on one end side of the plate-shaped member 98c. On the other hand, the aperture member 98-2 is formed of a substantially rectangular plate-shaped member.

  As shown in FIG. 7A, in the stop 98 having the above-described configuration, the stop pieces 98a and 98b do not rise vertically from the plate-like member 98c, but rise toward the recess 24 instead. I have. Therefore, the luminous flux of the reflected light L incident on the stop 98 is restricted in the longitudinal direction by the ends E1 and E2 located on the sides of the stop pieces 98a and 98b. That is, the first diaphragm is constituted by the diaphragm pieces 98a and 98b and the plate member 98c. On the other hand, one side of the diaphragm member 98-2 and one side of the concave portion 24 form ends E3 and E4 for restricting the light flux of the reflected light L in the lateral direction. In other words, the diaphragm 98 is configured such that the plate-shaped diaphragm member 98-2 and the plate-shaped member 98c constitute a second diaphragm, and a part of the second diaphragm is located at the same place as the first diaphragm. ing.

  The operation of the second throttle according to the present embodiment is as follows. That is, at the position P5 shown in FIG. 6, the upper beam of the reflected light L is regulated by the end E3 provided on the diaphragm member 98-2. Further, at a position P6 shown in FIG. 6, the lower light beam of the reflected light L is regulated by the end E4 provided on the diaphragm member 98-1. In other words, each stop member constituting the second stop restricts the luminous flux on the optical path from different sides at different positions of the reflected light on the optical path.

  FIG. 7B is a development view illustrating an example of a method for manufacturing the diaphragm member 98-1. As shown in FIG. 7B, the aperture member 98-1 is formed by forming a concave portion 24 having a shape as shown in FIG. 7B in the plate-like member 98c and bending the aperture member 98a and 98b at the dotted line. To rise. The shape of the aperture pieces 98a and 98b is not limited to a right triangle as shown in FIG. 7B as long as the ends E1 and E2 are formed, and may be various other shapes such as a triangle, a trapezoid, and the like. FIG. 7C illustrates the case of a triangle.

  The image reading optical system 86B will be described in more detail with reference to FIG. 8A is a side view of the image reading optical system 86B shown in FIG. 6 as viewed from the + Y direction, and FIG. 8B is a view of the image reading optical system 86B shown in FIG. 6 as viewed from the −Z direction. It is a top view.

  As shown in FIG. 8, the reflected light L is reflected by the imaging mirror 90, and the reflected light flux is in the longitudinal direction (X-axis direction) at ends E1 and E2 of the stop pieces 98 a and 98 b of the stop member 98-1. Be regulated. On the other hand, in the stop 98, the position to be stopped in the short direction (Z-axis direction) is separated. That is, first, the upper beam of the reflected light L is regulated by the end E3 of the diaphragm member 98-2, and then the lower beam is regulated by the end E4 of the diaphragm member 98-1. That is, the regulation by the end portion E3 and the regulation by the end portion E4 are performed at the positions of the reflected lights different from each other.

As described above, in the stop 98 according to the present embodiment, a part of the second stop is disposed at the same place as the first stop, and the other part of the second stop is located at a different place from the first stop. It is a form arranged in.
In other words, the end E3 is disposed separately from the ends E1 and E2, and the end E4 is connected to the ends E1 and E2. For this reason, since the image forming part 87B according to the present embodiment is contracted in the short direction, the image reading optical system 86B according to the present embodiment is shorter than the image reading optical system 200 according to the comparative example. The size is reduced depending on the direction.

<Modification of Third Embodiment>
A modification of the third embodiment will be described with reference to FIG. In the present embodiment, the other image reading optical systems 86C to 86E are configured by changing the shape or arrangement of the stop member 98-1. In FIG. 9, only a member corresponding to the diaphragm member 98-1 is shown, and illustration of a member corresponding to the diaphragm member 98-2 is omitted.

FIG. 9A shows a form in which the shape of the diaphragm member 98-1 is changed to a diaphragm member 97-1.
In the present embodiment, the stop 97 is formed by the stop member 97-1 and the stop member 98-2, and the stop 97 is used to form an image reading optical system 86C (not shown). FIG. 9A shows a front view and a bottom view of the aperture member 97-1. The position and size of the stop member 98-2 are the same as those of the stop member 98-2 shown in FIGS.

  As shown in FIG. 9A, the diaphragm member 97-1 is formed of a plate-like member 97c having a concave portion 26, and the plate-like portions on both sides of the concave portion 26 are bent in a predetermined direction to form the diaphragm pieces 97a and 97b. Is configured. Further, similarly to the stop member 98-1, the first stop E1 and E2, which are formed by the sides of the concave portion 26 along the short side direction, form a first stop for restricting the incident light beam in the longitudinal direction. In addition, an end portion E4 formed by a side along the longitudinal direction of the concave portion 26 and an end portion E3 of the diaphragm member 98-2 (see FIG. 7A) restrict the incident light beam in the short direction. Aperture is configured.

  Also with the stop 97 according to the present embodiment, the image reading optical system 86C is shortened in the lateral direction, so that the size of the image reading device 12 is further reduced. Further, according to the diaphragm member 97-1 according to the present embodiment, similar effects can be obtained with a simpler shape than the diaphragm member 98-1 described above.

  FIG. 9B shows an embodiment in which the direction of the aperture member 98-1 is changed and the image reading optical system 86D is configured. As shown in FIG. 9B, in the image reading optical system 86D, the diaphragm member 98-1 is rotated by 180 ° with respect to the image reading optical system 86B shown in FIG. Are arranged substantially in parallel with each other. Even with this arrangement, the mutual positional relationship between the end portions E1, E2, and E4 is the same as that of the image reading optical system 86B, and the arrangement position of the diaphragm member 98-2 (the upper light beam is restricted or the lower light beam is Whether or not to restrict) may determine the arrangement of the end E3 in consideration of the arrangement of the ends E1, E2, and E4. In the present embodiment, since the plate member 98c is parallel to the light beam incident on the imaging mirror 90, the image reading optical system 86D according to the present embodiment is compared with the image reading optical system 200 according to the comparative example. The image reading device 12 is further miniaturized.

  FIG. 9C shows an embodiment in which the image reading optical system 86E is configured by changing the inclination of the diaphragm member 98-1 shown in FIG. That is, as shown in FIG. 9C, the aperture member 98-1 does not need to be parallel to the upper light beam, and may be inclined in consideration of a positional relationship with another configuration. Furthermore, a part of the second diaphragm may be constituted by the end of the plate member 98c at the same time as the diaphragm member 98-1 is inclined. FIG. 9C illustrates a case where the lower light beam is regulated by the end of the plate member 98c at the position P7, and the upper light beam is regulated by the end E4 of the diaphragm member 98-1 at the position P8. In this case, it is not necessary to arrange the aperture member 98-2.

  In the above-described embodiment, an example in which imaging mirrors 90 and 92 (in the present embodiment, concave mirrors) having power in a predetermined direction are used as the reflection mirrors constituting the image reading optical system is exemplified. Although the description has been made, the present invention is not limited to this. For example, if a plane mirror is arranged between the image forming mirror 90 and the image forming mirror 92, the optical path is folded and the length of the image reading optical system 86 in the Y-axis direction is shortened, so that the size is further reduced.

  When the imaging mirrors 90 and 92 having power in a predetermined direction are used as the reflection mirrors constituting the image reading optical system, the directions of the powers of the imaging mirrors 90 and 92 are the longitudinal directions, respectively. Or in the short direction. Further, both the imaging mirrors 90 and 92 may have power, or only one of them may have power.

  Further, in the above-described embodiment, an example in which two image forming mirrors (image forming mirror 90 and image forming mirror 92) are used has been described. However, the present invention is not limited to this, and an example in which three or more image forming mirrors are used. Is also good. For example, a configuration may be adopted in which one or more imaging mirrors are further disposed between the mirror 85 and the imaging mirror 90 or between the imaging mirror 92 and the sensor 88 to turn back the traveling light.

12 Image reading devices 20, 24, 26 Recess 22 Opening 50 Automatic document feeder 52 Image reading processor 60 Document table 61 Document conveyance path 62 Output table 63 Paper sending roll 64 Sending roll 65 Pre-positioning roll 66 Positioning roll 67 Platen roll 68 Out roll 69 Discharge roll 70 Platen glass 75 Housing 76 Reading unit 80 Illumination unit 82 Diffuse reflecting members 83, 84, 85 Mirrors 86, 86A, 86B, 86C, 86D, 86E Image reading optical systems 87, 87A, 87B Imaging unit 88 Sensors 90, 92 Imaging mirrors 94, 96, 97, 98, 99 Apertures 97-1, 98-1, 98-2 Aperture members 97a, 97b, 98a, 98b, 99a, 99b Aperture pieces 97c, 98c Plate members 100 and 102 Imaging mirror 104 Aperture 106 Sensor 11 Aperture 110a, 110b, 110c, 110d diaphragm member 112 opening 200 image reading optical system E1, E2, E3, E4 end L reflected light Lu, Ld rays M reading position P1~P8 position

Claims (8)

An image reading unit in which a plurality of reading elements are arranged in a first direction;
A first reflective optical system that reflects light reflected from a reading target with irradiation light from a light source;
A first stop for restricting light reflected by the first reflective optical system in the first direction;
A second reflection-type optical system that reflects light that has passed through the first diaphragm among the light reflected by the first reflection-type optical system and guides the light to the image reading unit;
A second diaphragm for restricting light incident by a first diaphragm member and a second diaphragm member in a second direction intersecting the first direction, wherein the first diaphragm member and the second diaphragm member A second stop for restricting a light beam on the optical path from different sides in the second direction, at a position of the return light different from the stop member on the optical path;
An image reading optical system including: 2. The image reading optical system according to claim 1, wherein at least one of the first stop member and the second stop member is arranged at the same position of the reflected light on the optical path as the first stop. 3. The image reading optical system according to claim 2, wherein at least one of the first stop member and the second stop member is integrated with the first stop. The first aperture member is formed of a plate-like member, and regulates light incident on one side of the plate-like member in the second direction,
The second aperture member is integrated with the first aperture, and regulates light incident on a side of the concave portion provided in the first aperture along the first direction in the second direction. The image reading optical system according to claim 3. The first diaphragm rises from an end of the concave portion and is arranged in the first direction, and has two diaphragm pieces having oblique sides facing light reflected by the first reflective optical system. 5. The image reading optical system according to claim 4, further comprising: regulating the light reflected by the first reflection type optical system by the two stop pieces in the first direction. 6. Since the first aperture member and the second aperture member are formed continuously with the first aperture, the first aperture and the second aperture are integrated and an integrated aperture is formed. Composed,
The integrated diaphragm is formed of a plate-like member having a rectangular concave portion that opens in the second direction, and the first diaphragm is constituted by two sides of the concave portion along the second direction. 4. The image reading optical system according to claim 3, wherein the side of the recess along the first direction and the side of the outer periphery of the integral stop along the first direction constitute the second stop. 5. Since the first aperture member and the second aperture member are formed continuously with the first aperture, the first aperture and the second aperture are integrated and an integrated aperture is formed. Composed,
The integrated diaphragm,
A first opening having a rectangular shape having two sides along the second direction in which the first diaphragm is formed;
A second opening and a third opening provided continuously on both sides in the second direction with respect to the first opening, wherein the first opening of the second opening is provided. The second aperture is constituted by a side along the first direction on the opposite side to the portion and a side along the first direction on the opposite side of the third opening from the first opening. The image reading optical system according to claim 3, further comprising a second opening and a third opening. A light source for irradiating light to the object to be read;
An image reading optical system according to any one of claims 1 to 7,
An image reading device including: