Image reading optical system and image reading device

Abstract

The present invention provides an image reading optical system and an image reading device, which can reduce the bending angle of a first light path incident on a light reflecting portion and a second light path emitted after reflection. The image reading optical system includes: an image reading portion, in which reading elements of incident light are arranged; a plurality of light reflecting portions, which reflect light from a reading object to the image reading portion; and a first aperture, which limits light from one light reflecting portion to the next light reflecting portion in a specific direction, and includes a first light shielding portion and a second light shielding portion that shield a portion of the light, wherein the first light shielding portion and the second light shielding portion are arranged in a manner that the positions from one light reflecting portion in the traveling direction of the light are different from each other, and the first light shielding portion and the second light shielding portion are located on a substantially common plane; and the first light shielding portion is arranged in a manner that the optical axis of light incident on one light reflecting portion is arranged.

Description

Technical Field

[0001] The invention relates to an image reading optical system and an image reading device. Background Art

[0002] Patent Document 1 discloses a structure in which, in an imaging optical system for imaging image information of an object plane on a line sensor, a plurality of reflection surfaces located in an optical path from the object plane to the line sensor are all off-axial reflection surfaces.

[0003] Patent Document 2 discloses a structure in which an imaging optical system includes two off-axis optical elements.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] [Patent Document 1] Japanese Patent No. 4497805

[0007] [Patent Document 2] Japanese Patent No. 4817773 Summary of the invention

[0008] [Problems to be solved by the invention]

[0009] In an optical system that reads an image, a light shielding portion or the like is provided to limit light and thereby narrow the light.

[0010] Here, in an optical system that uses a plurality of light reflecting parts to reflect light and image the light on an image reading part (sensor), when the position of the light shielding part used for the aperture is aligned on a plane perpendicular to the optical axis, or the limiting member used to limit the light is arranged in a direction perpendicular to the optical axis direction, the light shielding part or the limiting member is likely to block the light on other optical paths reflected by the light reflecting part. In order to avoid the above phenomenon, other optical paths must be kept away from the light shielding part or the limiting member, and in this case, the bending angle of the optical path is likely to be enlarged.

[0011] The object of the present invention is to further reduce the bending angle of a first light path incident on a light reflecting portion and a second light path emitted after being reflected, compared with a case where the positions of a plurality of light shielding portions for limiting light and functioning as light apertures are aligned in the optical axis direction.

[0012] [Technical means to solve the problem]

[0013] The invention described in Technical Solution 1 is an image reading optical system, which includes: an image reading unit, in which reading elements of incident light are arranged; a plurality of light reflecting units, which reflect light from a reading object toward the image reading unit; and a first aperture, which limits light from one light reflecting unit to the next light reflecting unit in a specific direction, and includes a first light shielding unit and a second light shielding unit for shielding a portion of the light, wherein the first light shielding unit and the second light shielding unit are arranged in a manner that their positions in the direction of travel of the light are different from each other, and the first light shielding unit and the second light shielding unit are located on a substantially common plane; and the first light shielding unit is arranged in a manner along the optical axis of light incident on one of the light reflecting units.

[0014] The invention described in claim 2 is the image reading optical system described in claim 1, wherein the first light shielding portion and the second light shielding portion are formed by one member.

[0015] The invention described in Technical Solution 3 is based on the image reading optical system described in Technical Solution 1, wherein the first light shielding portion is arranged on the side of the optical path of the light incident to one of the light reflecting portions that is closer to the second light shielding portion than the second light shielding portion, and the distance between the first light shielding portion and one of the light reflecting portions is greater than the distance between the second light shielding portion and one of the light reflecting portions.

[0016] The invention described in Technical Solution 4 is based on the image reading optical system described in Technical Solution 1, which also includes a second aperture, having a light receiving surface that receives a portion of light from one light reflecting portion to the next light reflecting portion, limits the light in a direction intersecting the specific direction, and at least one of the first light shielding portion and the second light shielding portion is arranged at a position deviated from the plane passing through the light receiving surface.

[0017] The invention described in Technical Solution 5 is based on the image reading optical system described in Technical Solution 4, wherein the second aperture that limits the light in the intersection direction uses a protrusion to limit the light in the intersection direction, and the protrusion protrudes from the side of the light path of the light from one light reflecting portion to the next light reflecting portion toward the light path, and when the end of the end portion on the free end side of the protrusion passes through a plane, assuming that the end portion along the optical axis of the light incident on one light reflecting portion passes through a plane, the first light shielding portion and the second light shielding portion are both located on the side of the space where the base of the protrusion is located in two spaces opposite to each other with the end passing through the plane.

[0018] The invention described in Technical Solution 6 is based on the image reading optical system described in Technical Solution 1, wherein a plate-like component is provided, and the plate-like component is configured in a manner of transversely crossing the optical path of the light from one light reflecting portion to the next light reflecting portion, and is configured to be inclined relative to the optical axis of the light, and at least one of the first light shading portion and the second light shading portion is composed of the plate-like component.

[0019] The invention described in Technical Solution 7 is an image reading optical system according to Technical Solution 6, wherein the plate-like member is configured along the optical axis of the light incident on one of the light reflecting portions, and / or the plate-like member is configured parallel to the optical axis of the light emitted from the next light reflecting portion.

[0020] The invention described in Technical Solution 8 is based on the image reading optical system described in Technical Solution 7, wherein the optical axis of the light emitted from the next light reflecting portion is along the optical axis of the light incident to one light reflecting portion, and the plate-like member is configured in a manner along both the optical axis of the light incident to one light reflecting portion and the optical axis of the light emitted from the next light reflecting portion.

[0021] The invention described in Technical Solution 9 is based on the image reading optical system described in Technical Solution 6, wherein an opening is formed on the plate-like component to allow the light from one light reflecting part to the next light reflecting part to pass through, and also includes a second aperture, which limits the light from one light reflecting part to the next light reflecting part in a direction intersecting with the specific direction, and the second aperture that limits the light in the intersecting direction uses a protrusion protruding from the opening edge of the opening to limit the light in the intersecting direction.

[0022] The invention described in claim 10 is the image reading optical system described in claim 9, wherein the protrusion is formed integrally with the plate-like member.

[0023] The invention described in technical solution 11 is an image reading optical system, which includes: an image reading unit, in which reading elements of incident light are arranged; a plurality of light reflecting units, which reflect light from a reading object toward the image reading unit; and a plate-like member, which is arranged at an inclination relative to the direction of travel of light from one light reflecting unit to the next light reflecting unit, and is arranged in a manner that crosses the light to limit the light in a specific direction; and at least a portion of the plate-like member is arranged in a manner along the light incident to one of the light reflecting units.

[0024] The invention described in Technical Solution 12 is based on the image reading optical system described in Technical Solution 11, which also includes a second aperture, which uses a protrusion protruding from the plate-like component to limit the light from one light reflecting part to the next light reflecting part in a direction intersecting with the specific direction.

[0025] The invention described in claim 13 is the image reading optical system according to claim 12, wherein the plate-like member and the protrusion are formed integrally.

[0026] The invention described in Technical Solution 14 is based on the image reading optical system described in Technical Solution 11, wherein an opening is formed on the plate-like component for allowing the light from one light reflecting part to the next light reflecting part to pass through, and the light from one light reflecting part to the next light reflecting part is limited in the specific direction by using the part of the plate-like component located around the opening.

[0027] The invention described in Technical Solution 15 is an image reading optical system according to Technical Solution 11, wherein the plate-like member is configured along the optical axis of the light incident on one of the light reflecting portions, and / or is configured along the optical axis of the light emitted from the next one of the light reflecting portions.

[0028] The invention described in technical solution 16 is an image reading optical system, comprising: an image reading unit, in which a plurality of reading elements are arranged in a first direction; a plurality of light reflecting units, which reflect light from a reading object toward the image reading unit; a first aperture, having a light receiving surface that receives a portion of light from one light reflecting unit to the next light reflecting unit, and limits the light in the first direction; and a second aperture, which limits the light from one light reflecting unit to the next light reflecting unit in a second direction intersecting the first direction, and comprises a first light shielding unit and a second light shielding unit, wherein the first light shielding unit and the second light shielding unit are arranged so as to be staggered in positions in the direction of travel of the light and to shield a portion of the light, and at least one of the first light shielding unit and the second light shielding unit is arranged at a position deviated from the plane passing through the light receiving surface.

[0029] The invention described in Technical Solution 17 is an image reading device, comprising: a light source, emitting light to illuminate a reading object; and an image reading optical system, receiving light from the reading object and reading an image formed on the reading object; and the image reading optical system comprises the image reading optical system described in any one of Technical Solutions 1 to 16.

[0030] [Effects of the Invention]

[0031] According to the invention of technical solution 1, compared with the case where the positions of multiple shading parts for limiting light and acting as apertures of light are aligned in the optical axis direction, the bending angle of the first light path incident on the light reflecting part and the second light path emitted after reflection can be further reduced.

[0032] According to the invention of claim 2, the number of parts can be reduced compared to the case where a member constituting the first light shielding portion and a member constituting the second light shielding portion are provided separately.

[0033] According to the invention of technical solution 3, compared with the case where the distance between the first light shielding part and a light reflecting part is smaller than the distance between the second light shielding part and a light reflecting part, the optical path of light incident on a light reflecting part can be made closer to the optical path from one light reflecting part to the next light reflecting part.

[0034] According to the invention of technical solution 4, compared with the case where both the first light shading portion and the second light shading portion are located on a plane passing through the light receiving surface, the light path located next to the light path from one light reflecting portion to the next light reflecting portion can be made close to the light path from one light reflecting portion to the next light reflecting portion.

[0035] According to the invention of technical solution 5, compared with the case where the first shading portion is located in one of two spaces opposite to each other through a plane with the end portion clamped therebetween, and the second shading portion is located in the other space, the light path located next to the light path from one light reflecting portion to the next light reflecting portion can be made close to the light path from one light reflecting portion to the next light reflecting portion.

[0036] According to the invention of claim 6, compared with the case where the first light shielding portion or the second light shielding portion is formed using a member having a shape more complicated than a plate-like member, the structure can be simplified.

[0037] According to the invention of technical solution 7, compared with the case where the plate-like component is not arranged along the optical axis of the light incident to one light reflecting portion and is not arranged parallel to the optical axis of the light emitted from the next light reflecting portion, interference between the light incident to one light reflecting portion and the plate-like component, or interference between the light emitted from the next light reflecting portion and the plate-like component can be difficult to occur.

[0038] According to the invention of technical solution 8, compared with the case where the plate-like member is not along the optical axis of the light incident to one light reflecting portion and is not along the optical axis of the light emitted from the next light reflecting portion, it is possible to prevent interference between the light incident to one light reflecting portion and the plate-like member, or interference between the light emitted from the next light reflecting portion and the plate-like member.

[0039] According to the invention of claim 9, it is possible to limit light from one light reflecting portion to the next light reflecting portion in a direction intersecting with a specific direction.

[0040] According to the invention of claim 10, the structure can be simplified compared to a case where the protrusion and the plate-shaped member are not formed integrally.

[0041] According to the invention of technical solution 11, compared with the case where the positions of multiple shading parts for limiting light and acting as apertures of light are aligned in the optical axis direction, the bending angle of the first light path incident to the light reflecting part and the second light path emitted after reflection can be further reduced.

[0042] According to the invention of claim 12, it is possible to limit light from one light reflecting portion to the next light reflecting portion in a direction intersecting with a specific direction.

[0043] According to the invention of claim 13, the structure can be simplified compared to a case where the plate-like member and the protrusion are not formed integrally.

[0044] According to the invention of claim 14, the portion of the plate-like member located around the opening can be used to limit light from one light reflecting portion to the next light reflecting portion in a specific direction.

[0045] According to the invention of technical solution 15, compared with the case where the plate-like member is not along the optical axis of the light incident to one light reflecting portion or is not along the optical axis of the light emitted from the next light reflecting portion, it is possible to prevent interference between the light incident to one light reflecting portion and the plate-like member or interference between the light emitted from the next light reflecting portion and the plate-like member from occurring.

[0046] According to the invention of technical solution 16, compared with the case where the positions of multiple shading parts for limiting light and acting as apertures of light are aligned in the optical axis direction, the bending angle of the first light path incident to the light reflecting part and the second light path emitted after reflection can be further reduced.

[0047] According to the invention of technical solution 17, compared with the case where the positions of multiple shading parts for limiting light and acting as apertures of light are aligned in the optical axis direction, the bending angle of the first light path incident to the light reflecting part and the second light path emitted after reflection can be further reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a diagram showing an image reading device.

[0049] Figure 2 is from Figure 1 The sensor is viewed in the direction of arrow II.

[0050] Figure 3 It is a diagram for explaining the structure of the imaging unit.

[0051] Figure 4It is a diagram showing a comparative example of an image forming unit.

[0052] Figure 5 is from Figure 3 A diagram showing the aperture component when viewed in the direction indicated by arrow V.

[0053] Figure 6 It is a diagram showing another structural example.

[0054] Figure 7(A) is from Figure 3 FIG. 7(B) is a diagram showing the imaging portion when viewed from the direction of arrow VIIA. Figure 3 A diagram showing the imaging portion when viewed in the direction of arrow VIIB.

[0055] 8(A) and 8(B) are diagrams for explaining another structural example of the aperture member.

[0056] Fig. 9 This is a diagram showing another structural example of the reading unit.

[0057] 10(A) and 10(B) are diagrams for explaining another configuration example of the aperture member.

[0058] Explanation of symbols

[0059] 3H: Flat

[0060] 3Z: Plane

[0061] 12: Image reading device

[0062] 80: Lighting unit

[0063] 86: Image reading optical system

[0064] 88: Sensor

[0065] 90: First imaging lens

[0066] 92: Second imaging lens

[0067] 94A: Plate-like member

[0068] 94B: Open

[0069] 95: Reading components

[0070] 97A: End

[0071] 97X: End through plane

[0072] 100: First aperture

[0073] 110: Light receiving surface

[0074] 200: Second aperture

[0075] 210: First light shielding part

[0076] 220: Second light shielding part

[0077] 971: First protrusion

[0078] 972: Second protrusion

[0079] LG1: Optical axis

[0080] LG2: Optical axis

[0081] LG3: Optical axis

[0082] SP1: First Space

[0083] SP2: Second Space DETAILED DESCRIPTION

[0084] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0085] Figure 1 1 is a diagram showing the image reading device 12 according to the present embodiment.

[0086] The image reading device 12 includes a document transmitting unit 50 and an image reading processing unit 52 that reads an image formed on a document.

[0087] The document transmission section 50 is provided with a document table 60 on which a document is placed, a document conveying path 61 for conveying the document, and a discharge section 62 for discharging the document after the image has been read.

[0088] The document conveying path 61 is formed in a U shape.

[0089] The document conveying path 61 is provided with a plurality of document conveying rollers 60R, and the document placed on the document table 60 is conveyed along the document conveying path 61 by the plurality of document conveying rollers 60R. The document conveyed along the document conveying path 61 is finally discharged to the discharge unit 62.

[0090] The image reading device 12 has a function of reading an image of a document sent by the document sending unit 50 and a function of reading an image of a document placed on a platen glass 70 to be described later.

[0091] The image reading processing unit 52 is provided with a frame 75, and a platen glass 70 is provided on the upper portion of the frame 75. In the present embodiment, when an operator manually sets documents one by one, the documents are placed on the platen glass 70.

[0092] A reading unit 76 (carriage) for reading an image of a document is provided inside the housing 75 .

[0093] The reading unit 76 is provided movably along the platen glass 70 .

[0094] When reading an image of a document conveyed by the document transporting unit 50 , the reading unit 76 reads an image of a document that is disposed at the reading position M and passes over the reading unit 76 .

[0095] In addition, when reading an image of a document on the platen glass 70 , the reading unit 76 moves along the platen glass 70 to read the image of the document.

[0096] The reading unit 76 is provided with an illumination unit 80 as an example of a light source. The illumination unit 80 emits light to illuminate a document to be read.

[0097] Furthermore, in the reading unit 76 , an image reading optical system 86 is provided.

[0098] In the present embodiment, as the image reading optical system 86 , a mirror 83 , a mirror 84 , and a mirror 85 for reflecting the reflected light L from the document are provided.

[0099] Furthermore, in the present embodiment, as the image reading optical system 86 , an image forming unit 87 and a sensor 88 as an example of an image reading unit are provided.

[0100] The image forming section 87 is arranged on the downstream side of the mirror 85 in the traveling direction of the reflected light L.

[0101] In the lighting unit 80 , for example, a white light-emitting diode (LED) is provided.

[0102] Furthermore, in the present embodiment, a reflecting member 82 is provided for reflecting light emitted from the lighting unit 80 toward the document.

[0103] The imaging unit 87 shapes the light beam (optical image) of the reflected light L from the document into a shape suitable for receiving light in the sensor 88. The imaging unit 87 may also include an imaging lens (not shown) that optically reduces the reflected light L from the document (optical image of the document).

[0104] The sensor 88 performs photoelectric conversion on the optical image passed through the imaging unit 87 to generate respective color signals (image signals) of red (red, R), green (green, G), and blue (blue, B).

[0105] Figure 2 is from Figure 1 The figure is when the sensor 88 is observed in the direction of arrow II.

[0106] The sensor 88 includes, for example, a charge coupled device (CCD) image sensor.

[0107] like Figure 2 As shown, the sensor 88 is provided with three one-dimensional line sensors 99 arranged along the main scanning direction (first direction).

[0108] The three one-dimensional line sensors 99 are arranged side by side in the sub-scanning direction (a second direction intersecting (orthogonal) to the first direction).

[0109] To further explain, in the present embodiment, a configuration is adopted in which one-dimensional line sensors 99 for each color of R, G, and B are provided for each color, and three one-dimensional line sensors 99 are provided.

[0110] Here, a plurality of reading elements (imaging elements) 95 are arranged along the main scanning direction (first direction) in each one-dimensional line sensor 99. In other words, in each one-dimensional line sensor 99, a reading element 95 for receiving incident light is arranged.

[0111] Here, in this specification, the arrangement direction of the reading elements 95 refers to the arrangement direction of the reading elements 95 in one one-dimensional line sensor 99 provided for each color. In other words, the arrangement direction of the reading elements 95 refers to the main scanning direction.

[0112] As an additional note, in this embodiment, the three one-dimensional line sensors 99 are also arranged in the sub-scanning direction, and as a result, the three reading elements 95 are also arranged in the sub-scanning direction. However, in this specification, the arrangement direction of the reading elements 95 refers to the main scanning direction.

[0113] In other words, in this specification, the main scanning direction relative to the arrangement direction of the reading elements 95 refers to the arrangement direction of the reading elements 95 in each one-dimensional line sensor 99 set for each color, and the sub-scanning direction refers to the direction intersecting (orthogonal) with the arrangement direction.

[0114] In the present embodiment, when reading the document on the platen glass 70, the control unit (not shown) directs the reading unit 76 toward the Figure 1 Move in the direction of arrow C.

[0115] At this time, the reflected light L from the document is directed toward the sensor 88 via the mirror 83 , the mirror 84 , the mirror 85 , and the image forming unit 87 , and the document is read by the sensor 88 .

[0116] Next, in the present embodiment, when the reading unit 76 reaches a position facing the end of the document, the reading of one page of the document is completed.

[0117] The reading unit 76 is disposed at the reading position M when reading the document sent by the document sending unit 50 .

[0118] In this state, the document is conveyed by the document sending unit 50, and the document passes over the reading unit 76. At this time, as described above, the reflected light L from the document is directed to the sensor 88 via the mirrors 83, 84, 85, and the image forming unit 87, and the document is read by the sensor 88.

[0119] Here, as an optical system for shaping the reflected light L from the original, a reading optical system composed of a plurality of reflective optical systems having power (strength of light bending) in a predetermined direction is sometimes used. In a reading optical system composed of a plurality of reflective optical systems, a return optical path is inevitably generated.

[0120] In addition, in the reading optical system, an aperture is used for reasons such as adjusting the amount of light, adjusting the transfer function (Modulated Transfer Function, MTF) of the optical system, and increasing the depth of focus.

[0121] In the aperture, light is narrowed in both the long side direction (the direction in which the reading elements 95 are arranged, the main scanning direction) and the short side direction (the direction orthogonal to the direction in which the reading elements 95 are arranged, the sub-scanning direction) of the sensor 88.

[0122] Figure 3 It is a diagram for explaining the structure of the imaging unit 87.

[0123] The image forming section 87 is provided with a first image forming mirror 90 and a second image forming mirror 92 , and the reflected light L from the document to be read is reflected by each of the first image forming mirror 90 and the second image forming mirror 92 .

[0124] In other words, the image forming section 87 is provided with a plurality of light reflecting sections that reflect the reflected light L toward the sensor 88 , which is an example of an image reading section, and the reflected light L from the document is reflected by each of the plurality of light reflecting sections.

[0125] In the present embodiment, the reflected light L is first reflected by the first imaging mirror 90 which is an example of one light reflecting portion, and then is reflected by the second imaging mirror 92 which is an example of the next light reflecting portion.

[0126] The first imaging mirror 90 and the second imaging mirror 92 are concave mirrors, and have a function of reflecting the reflected light L and a function of collecting the reflected light L.

[0127] Therefore, in this embodiment, the width of light emitted from the first imaging mirror 90 and the second imaging mirror 92 (width in both the main scanning direction and the sub-scanning direction) gradually decreases toward the downstream side in the light traveling direction.

[0128] Furthermore, in the present embodiment, a diaphragm member 94 is provided between the first imaging mirror 90 and the second imaging mirror 92 .

[0129] The aperture member 94 blocks a part of the reflected light L reflected by the first imaging mirror 90 , and limits the reflected light L in the main scanning direction and the sub-scanning direction.

[0130] The aperture member 94 includes a first aperture 100 that limits the reflected light L in the main scanning direction (first direction). In other words, the aperture member 94 includes a first aperture 100 that limits the reflected light L in the same direction as the arrangement direction of the reading elements 95 .

[0131] Furthermore, the aperture member 94 is provided with a second aperture 200 that limits the reflected light L in the sub-scanning direction (a second direction intersecting the first direction).

[0132] As additionally described, the aperture member 94 is provided with a second aperture 200 that limits the reflected light L in a direction intersecting (orthogonal) with the arrangement direction of the reading elements 95 .

[0133] More specifically, the first aperture 100 includes a light receiving surface 110 that receives a portion of the reflected light L (hereinafter referred to as "inter-mirror light") from the first imaging mirror 90 to the second imaging mirror 92, and uses the light receiving surface 110 to block a portion of the inter-mirror light and limit the inter-mirror light in the main scanning direction.

[0134] In addition, the second aperture 200 includes a first light shielding portion 210 and a second light shielding portion 220 . The first light shielding portion 210 and the second light shielding portion 220 are used to shield a portion of the inter-mirror light, thereby limiting the inter-mirror light in the sub-scanning direction.

[0135] In the aperture member 94 , a plate-like member 94A including a flat plate is provided.

[0136] The plate-shaped member 94A is disposed so as to be inclined with respect to the traveling direction of the inter-lens light and so as to cross the inter-lens light.

[0137] In the present embodiment, a part of the plate-shaped member 94A functions as the first light shielding portion 210 and the second light shielding portion 220 , and the inter-lens light is limited by the plate-shaped member 94A.

[0138] The plate-like member 94A has an opening 94B formed therein through which inter-mirror light passes.

[0139] In the present embodiment, the portion of the plate-shaped member 94A located around the opening 94B is used to limit the inter-lens light.

[0140] To further explain, in the present embodiment, the portion of the plate-shaped member 94A located around the opening 94B serves as the first light shielding portion 210 and the second light shielding portion 220 .

[0141] Next, the first light shielding portion 210 and the second light shielding portion 220 located around the opening 94B shield a portion of the inter-mirror light, thereby limiting the inter-mirror light in an example of a specific direction, that is, the sub-scanning direction.

[0142] More specifically, in this embodiment, a portion of the plate-shaped member 94A located to the left of the opening 94B in the figure becomes the first light shielding portion 210 , and a portion of the plate-shaped member 94A located to the right of the opening 94B in the figure becomes the second light shielding portion 220 .

[0143] Next, in this embodiment, a portion of the inter-lens light is blocked by the first light shielding portion 210 and the second light shielding portion 220 , thereby reducing the inter-lens light.

[0144] Here, the first light shielding portion 210 and the second light shielding portion 220 are arranged so as to be different from each other in the traveling direction of the inter-lens light from the first imaging mirror 90 .

[0145] More specifically, in the present embodiment, the position of the first light shielding portion 210 and the position of the second light shielding portion 220 are different in the traveling direction of the inter-mirror light.

[0146] Furthermore, in the present embodiment, the first light shielding portion 210 is located on the downstream side of the second light shielding portion 220 in the traveling direction of the inter-mirror light.

[0147] Figure 4 It is a diagram showing a comparative example of the image forming unit 87 .

[0148] In the comparative example, the plate-shaped member 940A having the rectangular opening 940B is arranged in a direction perpendicular to the traveling direction of the inter-lens light. In other words, the plate-shaped member 940A is arranged perpendicular to the optical axis of the inter-lens light.

[0149] Furthermore, in the comparative example, the first light shielding portion 210 and the second light shielding portion 220 are placed on the plane 4A that is orthogonal to the optical axis of the inter-mirror light.

[0150] In the comparative example, interference between the plate-shaped member 940A and the incident light entering the first imaging mirror 90 (hereinafter referred to as "first mirror incident light"), and interference between the plate-shaped member 940A and the outgoing light emitted from the second imaging mirror 92 (hereinafter referred to as "second mirror outgoing light") are likely to occur.

[0151] In order to avoid the above phenomenon, the optical path of the incident light of the first mirror or the optical path of the emitted light of the second mirror must be kept away from the plate-shaped member 940A. In this case, the bending angle of the optical path is likely to be enlarged, which may easily cause the reading unit 76 (see Figure 1 ) on a larger scale.

[0152] In contrast, when the present embodiment (such as Figure 3 As shown in FIG. 1 , when the plate-shaped member 94A is arranged obliquely relative to the traveling direction of the inter-mirror light, interference between the plate-shaped member 94A and the incident light of the first mirror and interference between the plate-shaped member 94A and the emitted light of the second mirror are unlikely to occur.

[0153] As additionally explained, in this embodiment, the position of the first shading portion 210 and the second shading portion 220 in the traveling direction of the inter-mirror light will deviate, thereby making it difficult for the plate-shaped member 94A to interfere with the incident light of the first mirror, and for the plate-shaped member 94A to interfere with the emitted light of the second mirror.

[0154] Furthermore, in this embodiment, the first light shielding portion 210 and the second light shielding portion 220 are formed by one member.

[0155] As additionally described, in the present embodiment, the first light shielding portion 210 and the second light shielding portion 220 each include a portion of the common plate-shaped member 94A, and the first light shielding portion 210 and the second light shielding portion 220 include a common member.

[0156] Furthermore, in the present embodiment, the first light shielding portion 210 is disposed on a side closer to the optical path of the incident light of the first mirror than the second light shielding portion 220 is.

[0157] More specifically, in this embodiment, if Figure 3 As shown, the first light shielding portion 210 is located in the region R1 close to the first mirror incident light side among the two regions R1 and R2 opposite to each other with the optical axis LG1 of the inter-mirror light sandwiched therebetween, and the second light shielding portion 220 is located in the region R2 far from the first mirror incident light side.

[0158] As additionally explained, when comparing the positions in the direction orthogonal to the optical axis LG1 of the inter-mirror light, i.e., the sub-scanning direction (when comparing the positions in the direction indicated by the arrow 2X), the first light shielding portion 210 is arranged on the side of the optical path of the incident light of the first mirror that is closer to the second light shielding portion 220.

[0159] In addition, in the present embodiment, the distance between the first light shielding portion 210 and the first imaging mirror 90 is greater than the distance between the second light shielding portion 220 and the first imaging mirror 90 .

[0160] Here, for example, in a structure in which the distance between the first light shielding portion 210 and the first imaging mirror 90 is smaller than the distance between the second light shielding portion 220 and the first imaging mirror 90, and the first light shielding portion 210 is located at a position closer to the upstream side than the second light shielding portion 220, interference is easily generated between the plate-like member 94A (the portion of the plate-like member 94A on which the first light shielding portion 210 is provided) and the incident light of the first mirror.

[0161] In contrast, when the distance between the first light shielding portion 210 and the first imaging mirror 90 is greater than the distance between the second light shielding portion 220 and the first imaging mirror 90 as in the present embodiment, it is difficult to generate interference between the plate-like member 94A (the portion of the plate-like member 94A on which the first light shielding portion 210 is provided) and the incident light of the first mirror.

[0162] In addition, in the plate-shaped member 94A, the distance from the first light shielding portion 210 to the end of the plate-shaped member 94A on the first light shielding portion 210 side may be shorter than the distance from the second light shielding portion 220 to the end of the plate-shaped member 94A on the second light shielding portion 220 side. Thus, interference between the plate-shaped member 94A (the portion of the plate-shaped member 94A on the side where the first light shielding portion 210 is provided) and the incident light of the first mirror is less likely to occur.

[0163] In this embodiment, the plate-shaped member 94A is arranged along the optical axis LG2 of the first mirror incident light. Therefore, compared with a case where the plate-shaped member 94A is not arranged along the optical axis LG2 of the first mirror incident light, interference between the first mirror incident light and the plate-shaped member 94A is less likely to occur.

[0164] Furthermore, the plate-shaped member 94A may be arranged along the optical axis LG3 of the light emitted from the second mirror.

[0165] In addition, the plate-shaped member 94A may be arranged along both the optical axis LG2 of the light incident on the first mirror and the optical axis LG3 of the light emitted from the second mirror.

[0166] At this time, the optical axis LG3 of the light emitted from the second mirror is along the optical axis LG2 of the light incident on the first mirror, and the plate-shaped member 94A is along the two optical axes LG2 and LG3.

[0167] Figure 5 is from Figure 3 FIG. 1 is a diagram showing the aperture member 94 as viewed in the direction indicated by arrow V.

[0168] As described above, the rectangular plate-shaped member 94A is provided in the aperture member 94. In addition, the rectangular opening 94B is formed in the plate-shaped member 94A.

[0169] In the present embodiment, the inter-mirror light passes through the opening 94B formed in the plate-shaped member 94A.

[0170] Next, in the present embodiment, the portion of the plate-shaped member 94A located around the opening 94B is used to restrict the inter-mirror light in the sub-scanning direction which is an example of a specific direction.

[0171] More specifically, in the present embodiment, a portion of the plate-shaped member 94A located on the left side of the opening 94B in the figure is the first light shielding portion 210 , and a portion located on the right side of the opening 94B is the second light shielding portion 220 .

[0172] In this embodiment, the first light shielding portion 210 and the second light shielding portion 220 limit the inter-mirror light in a specific direction, ie, the sub-scanning direction.

[0173] Here, limiting light in a specific direction means blocking light that passes through the end of the light beam, that is, the end in the specific direction. In other words, limiting light in a specific direction means preventing the light beam from spreading in the specific direction.

[0174] Furthermore, in the present embodiment, a protrusion 97 is provided which protrudes from an opening edge 94D of the opening 94B toward the inner side of the opening 94B.

[0175] As additional instructions, in this embodiment, the following Figure 5 As shown, when the opening 94B (plate-shaped member 94A) is viewed from the front, there is a protrusion 97 that protrudes from an opening edge 94D of the opening 94B toward the inner side of the opening 94B.

[0176] In this embodiment, as described above, the first aperture 100 (see FIG. 1 ) is provided to limit the inter-mirror light in the main scanning direction. Figure 3 ), but the first aperture 100 includes the protrusion 97.

[0177] The protrusion 97 is as follows Figure 3 As shown in FIG. 1 , the projection 97 is arranged to protrude from the side of the optical path of the inter-mirror light toward the optical path. The projection 97 is formed in a plate shape and includes a projection piece.

[0178] In this embodiment, if Figure 5 As shown, a first protrusion 971 and a second protrusion 972 are provided as the protrusion 97 , and the first protrusion 971 and the second protrusion 972 are arranged so as to be offset from each other in the main scanning direction.

[0179] Furthermore, the first protrusion 971 and the second protrusion 972 are arranged with a gap provided between them.

[0180] Furthermore, the first protrusion 971 and the second protrusion 972 are formed integrally with the plate-like member 94A.

[0181] The first protrusion 971 and the second protrusion 972 block the light passing through the end portion in the main scanning direction among the light beams of the inter-mirror light, thereby limiting the inter-mirror light.

[0182] As additional explanation, the first protrusion 971 and the second protrusion 972 respectively include a light receiving surface 110 , and the light receiving surface 110 is used to block a portion of the inter-lens light, thereby limiting the inter-lens light.

[0183] In addition, in this embodiment, if Figure 3 As shown, when it is assumed that the end 97A on the free end side of the protrusion 97 passes through the plane 97X, the first shading portion 210 and the second shading portion 220 are located closer to the base side of the protrusion 97 (the connecting portion side between the protrusion 97 and the plate-like member 94A) than the end passing through the plane 97X.

[0184] More specifically, consider a plane passing through end 97A on the free end side of protrusion 97 and along optical axis LG2 of incident light on the first mirror, namely end passing plane 97X, and consider two spaces opposite to each other, namely first space SP1 and second space SP2, sandwiching end passing plane 97X.

[0185] At this time, both the first light shielding portion 210 and the second light shielding portion 220 are located in the two spaces, and the base side of the protrusion 97 is located on the second space SP2 side.

[0186] However, if Figure 6 As shown in the figure showing another configuration example, it is also possible to consider a form in which the portion corresponding to the first light shielding portion 210 is connected to the end portion 97A side of the protrusion 97. In other words, it is also possible to consider a form in which the plane 6A on which the first light shielding portion 210 is placed is different from the plane 6B on which the second light shielding portion 220 is placed.

[0187] Here, in the above embodiment, the first light shielding portion 210 is arranged near the incident light of the first mirror, so Figure 3 Compared with the structure of the present embodiment shown in the figure, interference between the reflected light L (first mirror incident light) and the aperture member 94 is more likely to occur.

[0188] In contrast, Figure 3In the structural example of the present embodiment shown, the first light shielding portion 210 and the second light shielding portion 220 are located on a common plane 3Z, and the common plane 3Z is inclined with respect to the optical axis LG1 of the inter-lens light. Here, the so-called common plane 3Z may be a substantially common plane, not just a completely common plane, and the plane of the second light shielding portion 220 may be a parallel plane separated within a certain range from the extension of the plane of the first light shielding portion 210, and the plane of the second light shielding portion 220 is not completely parallel to the plane of the first light shielding portion 210, and may be in a relationship of intersecting at a certain angle.

[0189] At this time, the first light shielding portion 210 is separated from the first mirror incident light, so that interference between the reflected light L (first mirror incident light) and the aperture member 94 is unlikely to occur.

[0190] If additional instructions are given, Figure 6 In the illustrated configuration example, a light shielding portion (a first light shielding portion 210 and a second light shielding portion 220 ) is connected to both a portion on the base side and a portion on the end 97A side of the protruding portion 97 .

[0191] In contrast, Figure 3 In the illustrated configuration example, the first light shielding portion 210 is not connected to the end portion 97A side of the protruding portion 97, and the first light shielding portion 210 is arranged close to the side of the light emitted from the second mirror.

[0192] In addition, Figure 3 In the illustrated configuration example, when a plane 3H passing through the light receiving surface 110 is assumed, the first light shielding portion 210 is not located on the plane 3H but is located at a position away from the plane 3H.

[0193] More specifically, in the traveling direction of the inter-mirror light, the first light shielding portion 210 is located on the downstream side of the plane 3H and is located away from the plane 3H.

[0194] In addition, Figure 3 In the illustrated configuration example, the common plane 3Z on which the first light shielding portion 210 and the second light shielding portion 220 are placed intersects with a plane 3H passing through the light receiving surface 110 provided on the first aperture 100 .

[0195] Figure 7(A) is from Figure 3 FIG. 7(B) is a diagram showing the imaging unit 87 when viewed from the direction of arrow VIIA. Figure 3 A diagram showing the imaging portion 87 when observed in the direction of arrow VIIB.

[0196] In this embodiment, as shown in FIG. 7(A) , incident light is reflected by the first imaging mirror 90 through the first mirror, thereby generating inter-mirror light.

[0197] Next, in the present embodiment, the inter-mirror light is restricted in the main scanning direction by the first protrusion 971 and the second protrusion 972 provided on the aperture member 94 .

[0198] Furthermore, in the present embodiment, as shown in FIG. 7B , the inter-mirror light is restricted in the sub-scanning direction by the first light shielding portion 210 and the second light shielding portion 220 provided on the aperture member 94 .

[0199] Furthermore, in the present embodiment, the case where two protrusions 97, namely the first protrusion 971 and the second protrusion 972, are provided has been described, but this is not limited to this, and a structure in which only one of the protrusions 97 is provided may be possible, for example, depending on the state of the light (light beam) to be restricted.

[0200] Similarly, regarding the first light shielding portion 210 and the second light shielding portion 220 , a configuration in which only one of the light shielding portions is provided may be adopted depending on the state of light (light beam) to be restricted, etc.

[0201] In addition, in this embodiment, the case where the opening 94B formed on the plate-like member 94A is formed into a rectangular shape is used as an example for explanation, but it is not limited to this. The shape of the opening 94B can also be set to other shapes such as a circle, an ellipse, a triangle, etc. according to the cross-sectional shape of the light beam of the reflected light L, etc.

[0202] FIG. 8(A) (a diagram illustrating another configuration example of the diaphragm member 94 ) illustrates a case where an opening 94B formed in a plate-like member 94A is formed in a trapezoidal shape.

[0203] In the above-described structural example, among the four sides of the first to fourth sides 181 to 184 located at the opening edge 94D, the first side 181 located at the portion corresponding to the lower bottom is longer than the third side 183 located at the portion corresponding to the upper bottom.

[0204] In the present embodiment, as shown in FIG. 8(B) , the width of the beam of the inter-lens light gradually increases at a position on the downstream side of the first aperture 100 .

[0205] At this time, if the first side 181 located at the portion corresponding to the lower bottom is made longer than the third side 183 located at the portion corresponding to the upper bottom, then compared with the case where the first side 181 is not longer than the third side 183, interference between the inter-mirror light and the plate-shaped component 94A is less likely to occur.

[0206] Furthermore, in the present embodiment, the case where the first shading portion 210 and the second shading portion 220 are formed on a common plate-like member 94A has been described, but this is not limited to this. As shown in Figures 10(A) and 10(B) (figures illustrating another structural example of the aperture member 94), it may also include plate-like members 991 and 992 that are independently arranged (including other members).

[0207] Furthermore, similarly to the above description, the first light shielding portion 210 and the second light shielding portion 220 (the plate-shaped member 991 and the plate-shaped member 992 ) are located on the common plane 3Z.

[0208] In addition, the above is an example of using the first imaging mirror 90 and the second imaging mirror 92 (concave mirror) having refractive power in predetermined directions (both the main scanning direction and the sub-scanning direction) as reflecting mirrors, but it is not limited to this. For example, a plane mirror may also be used.

[0209] In addition, when an imaging mirror having a diopter in a predetermined direction is used in the first imaging mirror 90 and the second imaging mirror 92, the diopter direction may be set to only the main scanning direction or only the sub-scanning direction. Furthermore, it may be set to both the main scanning direction and the sub-scanning direction.

[0210] In addition, both the first imaging mirror 90 and the second imaging mirror 92 may have refractive power, or only one of them may have refractive power.

[0211] Furthermore, in the above-described embodiment, a configuration example using two imaging mirrors (the first imaging mirror 90 and the second imaging mirror 92 ) has been described, but the present invention is not limited thereto, and a configuration using three or more imaging mirrors may be employed.

[0212] The imaging mirror may include resin such as plastic and be formed by vapor-depositing metal on a surface having a curvature, or may include glass or metal without including resin.

[0213] Furthermore, although mirrors having positive refractive power (condensing optical system) are required before and after the aperture, a mirror having negative refractive power (magnifying optical system) may exist therebetween.

[0214] As a necessary condition, it is sufficient that there exists an optical system or an optical system group having positive refractive power as a whole at least before the aperture (on the upstream side of the optical path), and there exists an optical system or an optical system group having positive refractive power as a whole after the aperture (on the downstream side of the optical path).

[0215] In addition, the reading unit 76 can also be set to Fig. 9 (A diagram showing another configuration example of the reading unit 76) shows a configuration.

[0216] exist Figure 1 In the structural example shown, the reflected light L is emitted from the left side of the sensor 88 to the sensor 88, and in Fig. 9 In the structure shown, the structure is as follows: after the reflected light L is reflected by a plurality of mirrors, the reflected light L is emitted toward the sensor 88 from the right side of the sensor 88 in the figure.

[0217] Although detailed illustrations are omitted, Fig. 9 In the configuration example shown, the aperture member 94 for limiting the inter-lens light is provided in the same manner as described above.

Claims

1. An image reading optical system, characterized in that include: An image reading section, in which reading elements of the incident light are arranged; a plurality of light reflecting parts for reflecting light from a reading object toward the image reading part; a first aperture that limits light from one of the light reflecting portions to the next of the light reflecting portions in a specific direction, and includes a first light shielding portion and a second light shielding portion that shield a portion of the light, wherein the first light shielding portion and the second light shielding portion are arranged in a manner that positions from one of the light reflecting portions in the traveling direction of the light are different from each other, the first light shielding portion and the second light shielding portion are located on a common plane, and the first light shielding portion is arranged in a manner that is along an optical axis of light incident on one of the light reflecting portions; as well as A second aperture has a light receiving surface that receives a portion of light from one of the light reflecting portions to a lower one of the light reflecting portions, and limits the light in a direction intersecting the specific direction; and At least one of the first light shielding portion and the second light shielding portion is arranged at a position deviated from a plane passing through the light receiving surface, the second aperture for limiting the light in the direction of the intersection, the light being limited in the direction of the intersection using a protrusion, the protrusion protruding from the side of the light path of the light from one light reflecting portion to the next light reflecting portion toward the light path, When the end portion passing through the end portion on the free end side of the protrusion passes through a plane, it is assumed that the end portion along the optical axis of the light incident on one of the light reflecting portions passes through a plane, The first light shielding portion and the second light shielding portion are both located on the space side where the base of the protrusion is located, among two spaces facing each other via a plane with the end portion interposed therebetween.

2. The image reading optical system according to claim 1, characterized in that: The first light shielding portion and the second light shielding portion are formed by one member.

3. The image reading optical system according to claim 1, characterized in that: The first light shielding portion is arranged on a side closer to the optical path of the light incident on one of the light reflecting portions than the second light shielding portion. The distance between the first light shielding portion and one of the light reflecting portions is greater than the distance between the second light shielding portion and one of the light reflecting portions.

4. The image reading optical system according to claim 1, characterized in that: A plate-like member is provided, the plate-like member is arranged so as to cross the optical path of the light from one of the light reflecting portions to the next of the light reflecting portions, and is arranged to be inclined with respect to the optical axis of the light, At least one of the first light shielding portion and the second light shielding portion is formed of the plate-shaped member.

5. The image reading optical system according to claim 4, characterized in that: The plate-shaped member is arranged along the optical axis of the light incident on one of the light reflecting portions, and / or the plate-shaped member is arranged parallel to the optical axis of the light emitted from the next light reflecting portion.

6. The image reading optical system according to claim 5, characterized in that: The optical axis of the light emitted from the next light reflecting portion is along the optical axis of the light incident on the one light reflecting portion, The plate-shaped member is arranged along both the optical axis of the light incident on one of the light reflecting portions and the optical axis of the light emitted from the next light reflecting portion.

7. The image reading optical system according to claim 4, characterized in that: The plate-like member has an opening formed therein for allowing the light from one light reflecting portion to the next light reflecting portion to pass therethrough. further comprising a second aperture, the second aperture being configured to limit the light from one light reflecting portion to a next light reflecting portion in a direction intersecting the specific direction, The second aperture that limits the light in the intersecting direction uses a protrusion that protrudes from an opening edge of the opening to limit the light in the intersecting direction.

8. The image reading optical system according to claim 7, characterized in that: The protrusion is formed integrally with the plate-like member.

9. An image reading device, characterized in that include: A light source that emits light to illuminate a reading object; as well as an image reading optical system that receives light from the reading object and reads an image formed on the reading object; and The image reading optical system includes the image reading optical system according to any one of claims 1 to 8.

Images