Image reading apparatus

Abstract

In an image reading device, lens arrays (71, 72) in which lens bodies (41) are arranged in a main scanning direction are connected with a gap (13) therebetween. A plurality of first slit parts and second slit parts (122) are provided between the lens arrays (71, 72) and the image sensor (11), the plurality of first slit parts and second slit parts (122) being arranged in the main scanning direction. The first slit section has a first light shielding plate (14) that separates the optical path of the light passing through the lens body (41). The second slit section (122) has a first light shielding plate (14), and a second light shielding plate (19) that restricts, on the gap (13) side, the optical path of the light passing through the lens body (41) closest to the gap (13). The second light-shielding plate (19) is positioned closer to the lens arrays (71, 72) than the first light-shielding plate (14) on the image sensor (11) side in the direction along the optical path, so that the field of view regions of two lens bodies (41) adjacent to each other across the gap (13) overlap on the light-receiving surface (22) of the image sensor (11).

Description

Technical Field

[0001] The present disclosure relates to an image reading device. Background Art

[0002] Conventionally, there has been an image reading device that uses a lens array formed by arranging lens bodies in an array, focuses transmitted light or reflected light from a reading object (an irradiated object), and reads an image focused by the lens array through an image sensor, thereby electronically converting an image, characters, a pattern, etc. on the reading object into two-dimensional image data.

[0003] In such an image reading device, when the length of the reading object in the main scanning direction is longer than the limit length of one lens array that can be manufactured, it is necessary to arrange and join a plurality of lens arrays in the main scanning direction. At this time, there is a joining method in which a plurality of lens arrays are arranged in the main scanning direction with a gap therebetween (for example, Patent Document 1).

[0004] In addition, in an image reading device, light focused by a plurality of adjacent lens bodies overlaps and forms an image on the image sensor. Images of light focused by a plurality of adjacent lens bodies have a positional shift from each other due to differences in optical characteristics of each lens body, assembly errors, distance shifts in the focal position on the reading object side of the reading object and the lens body, etc., and are formed on the image sensor. Therefore, the allowable range of the position of the reading object when it is determined that the focus is aligned becomes smaller with respect to the focal position of the lens body. In other words, the depth of field of the image reading device becomes shallower. Therefore, the following example has been proposed (for example, Patent Document 2): A slit portion is provided between the lens array and the image sensor, and the slit portion includes a light shielding plate that separates the optical path of light passing through one lens body from the optical path of light passing through another adjacent lens body. Thereby, it has been demonstrated that by restricting the overlap of the optical paths of light passing through a plurality of adjacent lens bodies, the depth of field can be increased.

[0005] Patent Document 1: International Publication No. 2020 / 090136

[0006] Patent Document 2: International Publication No. 2021 / 193945

[0007] In the structure of Patent Document 2, in order to increase the depth of field, a slit portion is provided between the lens array and the image sensor to restrict the expansion of the optical path of light passing through the lens body and restrict the overlap of the expansion of the optical paths of light passing through adjacent lens bodies. Here, when a plurality of lens arrays are arranged with a gap in the main scanning direction, the expansion of the optical paths of light passing through two adjacent lens bodies with a gap therebetween does not overlap in the gap portion, and the read image becomes discontinuous. The expansion of the optical path of light passing through the lens body is also referred to as the field of view region of the lens body. Summary of the Invention

[0008] The present disclosure is made to solve the above-described problems, and an object thereof is to provide an image reading apparatus that can read an image without discontinuity in a gap portion between lens arrays even when using a plurality of lens arrays arranged with gaps in the main scanning direction.

[0009] The image reading apparatus of the present disclosure includes: a plurality of lens arrays arranged with gaps in the main scanning direction, each lens array having a plurality of lens bodies arranged in the main scanning direction; and an image sensor that receives light focused by the lens bodies. The image reading apparatus further includes a plurality of slit portions, one or more of which are provided for one lens array between the lens array and the image sensor and arranged in the main scanning direction. The plurality of slit portions include a second slit portion that is a slit portion having a first light shielding plate and a second light shielding plate. The first light shielding plate separates the optical path of light that has passed through one lens body from the optical path of light that has passed through an adjacent lens body. The second slit portion restricts the optical path of light that has passed through the lens body closest to the gap on the gap side in the main scanning direction, and the position on the image sensor side in the direction of the optical path is closer to the lens array side than the first light shielding plate, so that the field-of-view region of the lens body representing the expansion of the restricted optical path overlaps with the field-of-view region of the lens body adjacent across the gap on the surface of the image sensor on the lens array side. When a plurality of slit portions are provided for one lens array, the plurality of slit portions further include a first slit portion that is a slit portion including only the first light shielding plate.

[0010] According to the present disclosure, even when using a plurality of lens arrays arranged with gaps in the main scanning direction, since the field-of-view regions of the lens bodies closest to the gap restricted by the second light shielding plate overlap, the read image does not become discontinuous in the gap portion between the lens arrays. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a perspective view of the image reading apparatus according to Embodiment 1 of the present disclosure.

[0012] Figure 2 is a side view in the main scanning direction of a state in which a frame side plate of the image reading apparatus according to Embodiment 1 of the present disclosure is removed.

[0013] Figure 3 is a perspective view of the lens array included in the image reading apparatus according to Embodiment 1 of the present disclosure.

[0014] Figure 4 is a top view of the lens array included in the image reading apparatus according to Embodiment 1 of the present disclosure when viewed from the optical axis direction.

[0015] Figure 5 is a front view of the lens array to which the slit portion included in the image reading apparatus according to Embodiment 1 of the present disclosure is attached.

[0016] Figure 6 is used as a connection Figure 5 An enlarged view of part A of the lens array shown.

[0017] Figure 7A is a perspective view of the first slit portion of the image reading device according to Embodiment 1 of the present disclosure as viewed from the image sensor side.

[0018] Figure 7B is a perspective view of the first slit portion of Embodiment 1 as viewed from the lens array side.

[0019] Figure 7C is a perspective view of the first slit portion of Embodiment 1 as viewed from the side of an adjacent slit portion.

[0020] Figure 8A is a perspective view of the second slit portion of the image reading device according to Embodiment 1 of the present disclosure as viewed from the image sensor side.

[0021] Figure 8B is a perspective view of the second slit portion of Embodiment 1 as viewed from the lens array side.

[0022] Figure 8C is a perspective view of the second slit portion of Embodiment 1 as viewed from the gap side.

[0023] Figure 9 is from Figure 6 A perspective view of the slit portion and the lens array as viewed from side B (image sensor side) shown.

[0024] Figure 10 is from Figure 9 A bottom view of the lens array with the slit portion attached as viewed in direction C shown.

[0025] Figure 11 is a schematic diagram for explaining the problem that occurs when the second light shielding plate 19 of the image reading device according to Embodiment 1 of the present disclosure is not provided.

[0026] Figure 12 is a schematic diagram for explaining the effect of the second light shielding plate 19 of the image reading device according to Embodiment 1 of the present disclosure.

[0027] Figure 13A is a perspective view of the first slit portion of the image reading device according to Embodiment 2 of the present disclosure as viewed from the image sensor side.

[0028] Figure 13B is a perspective view of the first slit portion of Embodiment 2 as viewed from the lens array side.

[0029] Figure 14It is a perspective view of the second slit portion included in the image reading device according to Embodiment 2 of the present disclosure, as viewed from the image sensor side.

[0030] Figure 15 It is a perspective view of the lens array portion to which the slit portion included in the image reading device according to Embodiment 2 of the present disclosure is attached.

[0031] Figure 16 It is a top view of the lens array portion to which the slit portion included in the image reading device according to Embodiment 2 of the present disclosure is attached.

[0032] Figure 17A It is a perspective view of the first slit portion included in the image reading device according to Embodiment 3 of the present disclosure, as viewed from the image sensor side.

[0033] Figure 17B It is a perspective view of the first slit portion of Embodiment 3, as viewed from the lens array side.

[0034] Figure 18 It is a perspective view of the second slit portion included in the image reading device according to Embodiment 3 of the present disclosure, as viewed from the image sensor side.

[0035] Figure 19 It is a perspective view of the lens array to which the slit portion included in the image reading device according to Embodiment 3 of the present disclosure is attached.

[0036] Figure 20 It is from Figure 19 The bottom view of the lens array to which the slit portion is attached, as viewed in the direction E shown. Detailed Embodiments

[0037] Embodiment 1.

[0038] Hereinafter, the image reading device 101 of Embodiment 1 will be described using Figures 1 to 12 In the respective figures, X, Y, and Z represent coordinate axes. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The X-axis direction is referred to as the main scanning direction, the Y-axis direction is referred to as the sub-scanning direction, and the Z-axis direction is referred to as the optical axis direction. The image reading device 101 includes an image sensor. The main scanning direction is the direction in which the image sensors are arranged. The sub-scanning direction is the direction in which the object to be read moves relative to the image reading device 101. The optical axis direction is the direction along the optical path through which light from the object to be read travels, and is the central axis direction of the lens body through which light from the object to be read passes. In the present disclosure, the case where the object to be read is conveyed above the image reading device 101 is taken as an example for description.

[0039] First, the outline of the structure of the image reading device 101 will be described using Figure 1 , Figure 2

[0040] Figure 1 is a perspective view of the image reading device 101 according to Embodiment 1 of the present disclosure. Figure 2 is a side view in the main scanning direction of the state in which the frame side plate 3 of the image reading device 101 according to Embodiment 1 of the present disclosure is removed.

[0041] As Figure 1 , Figure 2 shown, the image reading device 101 includes: a frame 1, a transparent body 2, a frame side plate 3, a substrate support plate 5, a lens fixing plate 6, a lens array 7, a sensor driving substrate 8, a sensor substrate 9, an image sensor 11, and a slit portion 12. The image reading device 101 reads image information of a reading object (not shown).

[0042] The reading object is, for example, a banknote, a security, and other general documents. The reading object is a reading medium (irradiated object) from which its image information is read.

[0043] The frame 1 is a box-shaped body with the main scanning direction (X-axis direction) as the length direction. A space extending in the main scanning direction (X-axis direction) is formed inside the frame 1. The frame 1 has a rectangular opening on the reading object side (upper surface). The frame 1 has openings at both ends in the main scanning direction (X-axis direction) of the frame 1. The frame 1 has an opening on the side opposite to the reading object side. The width direction of the frame 1 corresponds to the sub-scanning direction (Y-axis direction). The frame 1 is formed of, for example, aluminum or other metals, or resin.

[0044] The frame 1 houses or holds the lens fixing plate 6, the lens array 7, the sensor driving substrate 8, the sensor substrate 9, the image sensor 11, and the slit portion 12.

[0045] The transparent body 2 is provided on the upper surface of the frame 1 and has a shape that closes the opening. The transparent body 2 is formed of, for example, transparent resin or transparent glass. Both the surface of the transparent body 2 on the frame 1 side and the surface on the side opposite to the frame 1 side are formed into flat plate shapes and extend along the main scanning direction (X-axis direction). The surface of the transparent body 2 on the frame 1 side is called the inner surface, and the surface on the side opposite to the frame 1 side is called the outer surface.

[0046] The outer surface of the transparent body 2 is a reading surface for reading an image from the reading object. The reading surface restricts the reading position in the optical axis direction (Z-axis direction) of the reading object.

[0047] The frame side plate 3 is a plate material made of, for example, a metal plate. The frame side plate 3 closes both ends in the main scanning direction (X-axis direction) of the space formed in the frame 1 and forms the side surface of the frame 1.

[0048] The substrate support plate 5 is formed to block the bottom of the space in the frame 1 on the side opposite to the upper surface where the transparent body 2 is provided. The substrate support plate 5 is fixed to the frame 1 with tape, adhesive, screws, etc. The substrate support plate 5, the frame side plate 3, and the frame 1 are formed of materials that block light from the outside.

[0049] The frame 1, the transparent body 2, the frame side plate 3, and the substrate support plate 5 seal the space where the image sensor 11 is located. Except for the transparent body 2, light is not allowed to pass through. Therefore, the substrate support plate 5, the frame side plate 3, and the frame 1 can block the light incident on the image sensor 11 from the outside of the image reading device 101. In addition, it also has the effect of preventing foreign matters such as garbage and dust from entering the inside of the image reading device 101.

[0050] A plurality of lens arrays 7 are arranged at intervals in the main scanning direction (X-axis direction) between the object to be read and the image sensor 11. The plurality of lens arrays 7 are adhered to the lens fixing plate 6 with double-sided tape, adhesive, etc. The lens fixing plate 6 to which the lens array 7 is adhered is fixed to the frame 1 with screws. The optical axis of each lens body 41 of the lens array 7 is perpendicular to the reading surface. The lens array 7 reflects or transmits the light emitted from the lighting device (not shown) by the object to be read, focuses the light passing through the transparent body 2, and forms an image on the image sensor 11 inside the frame 1. The lighting device can be housed in the frame 1 or can also be provided outside the frame 1.

[0051] The image sensor 11 receives the light focused by the lens array 7, performs photoelectric conversion, and outputs an electrical signal. The image sensor 11 is arranged in an array according to the arrangement of the plurality of lens bodies 41. For example, a light receiving portion and a driving circuit formed of semiconductor chips are mounted on the image sensor 11. The image sensor 11 is fixed to the sensor substrate 9 with an adhesive.

[0052] The sensor substrate 9 is a substrate formed of glass epoxy or other resin. The image sensor 11 is mounted on the sensor substrate 9. The sensor substrate 9 and the sensor driving substrate 8 having a circuit for driving the image sensor 11 are fixed to the substrate support plate 5 with an adhesive, tape, screws, etc. The sensor substrate 9 is fixed to the surface of the substrate support plate 5 on the side of the lens array. At this time, the straight line on which the optical axis of each lens body 41 of the lens array 7 exists passes through the center of the light receiving portion mounted on the image sensor 11 and coincides with the straight line perpendicular to the light receiving surface.

[0053] Next, refer to Figure 3 、 Figure 4 to describe the details of the lens array 7. Figure 3 It is a perspective view of the lens array 7 included in the image reading device according to Embodiment 1 of the present disclosure. Figure 4It is a top view of the lens array 7 included in the image reading device according to Embodiment 1 of the present disclosure, as viewed from the optical axis direction (Z-axis direction).

[0054] As Figure 3 , Figure 4 shown, the lens array 7 is formed by arranging a plurality of lens bodies 41 along the main scanning direction (X-axis direction). The lens body 41 focuses the light from the object to be read that passes through the transparent body 2.

[0055] In addition, the lens array 7 in the embodiment of the present disclosure is a rod lens array. A rod lens array is formed by arranging rod lenses in an array. The rod lens is formed of glass, other inorganic materials, resin, etc., and has a radial refractive index distribution capable of imaging an erect and same-sized image with a predetermined opening angle and conjugate length (distance from focus to focus). The rod lens is an example, and a lens array formed by arranging lens bodies that are not rod lenses in an array can be used.

[0056] The holding portion 42 extends along the main scanning direction (X-axis direction) and is provided on both sides of the lens array 7 in the sub-scanning direction (Y-axis direction). That is, the holding portion 42 holds a plurality of lens bodies 41 that are closely arranged in a row without gaps along the main scanning direction (X-axis direction) from both sides in the sub-scanning direction (Y-axis direction).

[0057] The holding portion 42 is formed of resin, for example, and is in a plate shape here. The lens array 7 is bonded to the lens fixing plate 6 via the holding portion 42 with an adhesive, tape, etc.

[0058] The light incident surface 43 on the transparent body 2 side of the lens array 7 and the light incident side surface 44 on the transparent body 2 side of the holding portion 42 are precisely surface polished and are in the same plane. Similarly, the light exit surface 45 (not shown) on the image sensor side of the lens array 7 and the light exit side surface 46 (not shown) on the image sensor 11 side of the holding portion 42 are precisely surface polished and are in the same plane.

[0059] A slit portion 12 is connected to the surface of the holding portion 42 on the image sensor 11 side. Here, the surface of the holding portion 42 on the image sensor 11 side and the surface of the slit portion 12 on the transparent body 2 side may be in contact with each other, or may have a gap of a certain size or less.

[0060] Next, Figures 5 to 10 will be used to explain the characteristic optical system of the present disclosure. The image reading device in the present disclosure includes a plurality of lens arrays 7 arranged along the main scanning direction (X-axis direction). Therefore, for ease of explanation, adjacent lens arrays 7 are respectively distinguished as lens arrays 71 and 72.

[0061] Figure 5This is a front view of the lens arrays 71 and 72 of the slit portion to which the image reading device 101 of Embodiment 1 of the present disclosure is attached. Figure 6 This is Figure 5 an enlarged view of portion A surrounded by a dotted line of the portion connecting the lens arrays 71 and 72 shown. The lens arrays 71 and 72 are adhesively fixed to the lens fixing plate 6 extending in the main scanning direction (X-axis direction) by an adhesive or double-sided tape. The lens arrays 71 and 72 are provided with a gap 13 therebetween. That is, the respective lens bodies 41 separated by the gap 13 do not contact each other.

[0062] When the two lens arrays 71 and 72 are brought close to and attached to the same lens fixing plate 6, the linear expansion coefficient of the lens fixing plate 6 is greater than that of the lens arrays 71 and 72. Therefore, at low temperatures, the side surface of the lens array 71 contacts the side surface of the lens array 72, and the lens arrays 71 and 72 are in a state of pushing against each other. If a force acts on the lens arrays 71 and 72 through this pushing, the relative positional relationship of the respective lens bodies 41 facing each other across the gap 13 changes. If the relative positional relationship changes, the light focused by the respective lens bodies 41 facing each other across the gap 13 forms an image on the image sensor 11 with a positional shift, and thus a multiple image in which multiple images of the reading object at different positions overlap is generated. Therefore, the gap 13 is set to a width that can absorb the difference in the length in the main scanning direction (X-axis direction) by which the lens arrays 71 and 72 contract due to a temperature decrease and the length in the main scanning direction (X-axis direction) by which the lens fixing plate 6 contracts due to a temperature decrease. By setting the gap 13 to a predetermined width, it is possible to prevent the lens arrays 71 and 72 from contacting and pushing against each other at low temperatures. Therefore, it is possible to suppress the generation of multiple images between the lens arrays 71 and 72.

[0063] A plurality of slit portions 12 are arranged along the main scanning direction (X-axis direction) and are adhesively fixed to the image sensor 11 side of the holding portion 42 that holds the lens arrays 71 and 72. The slit portion 12 includes a first slit portion 121 and a second slit portion 122.

[0064] The second slit portion 122 is fixed to the end portion of the lens arrays 71 and 72 closest to the gap 13. For the portions other than the end portion closest to the gap, the first slit portion 121 is fixed.

[0065] Using Figures 7A - 7C this, the details of the first slit portion 121 will be described. Figures 7A - 7C This is an external view of the first slit portion 121 included in the image reading device 101 of Embodiment 1 of the present disclosure, Figure 7A This is a perspective view of the first slit portion 121 as viewed from the image sensor 11 side, Figure 7B This is a perspective view of the first slit portion 121 as viewed from the lens array 7 side,Figure 7C is a perspective view of the first slit portion 121 as viewed from the side of the adjacent slit portions 121 and 122.

[0066] As Figures 7A - 7C shown, in the first slit portion 121, side plates 15 are provided on both sides of the first light-shielding plate 14 in the sub-scanning direction (Y-axis direction) and hold the adjacent first light-shielding plates 14. More specifically, a plurality of light-shielding plates 14 held by the side plates 15 at both ends in the sub-scanning direction (Y-axis direction) are arranged in parallel in the main scanning direction (X-axis direction) with a certain interval therebetween. Here, all of the plurality of light-shielding plates 14 included in the first slit portion 121 are of a single type of first light-shielding plate 14 having the same length in the Z-axis direction. More specifically, when the first slit portion 121 is mounted on the lens array 7, all of the first light-shielding plates 14 included in the first slit portion 121 have end portions on the image sensor 11 side that are at the same distance from the surface on the image sensor 11 side of the lens array 7 in the optical axis direction (Z-axis direction). Protrusion portions 16 and 17 that protrude from a part of the end face are provided on the end face on the lens array 7 side of the side plate 15. In addition, although in the Figures 7A - 7C shown first slit portion 121, one protrusion portion 16 is provided and two protrusion portions 17 are provided, the number of the protrusion portions 16 and 17 can be any number.

[0067] The protrusion portion 16 serves as an adhesive edge for fixing the first slit portion 121 to the holding portion 42 of the lens array 7 by an adhesive. As Figures 7A - 7C shown, in the case where one protrusion portion 16 is provided, it is easy to obtain a space for a device for applying an adhesive or an insertion tool, and thus it is easy to apply the adhesive. As a device for applying an adhesive, for example, a dispenser is used.

[0068] As Figure 2 shown, the protrusion portion 17 is a portion that contacts the contact surface 61 of the lens fixing plate 6. The contact surface 61 is the side surface on the image sensor 11 side of the lens fixing plate 6. The length of the protrusion portion 17 is determined according to the position where the lens array 7 is fixed to the lens fixing plate 6. The first slit portion 121 having two protrusion portions 17 of such determined length is fixed to the lens array 7 in a state where both protrusion portions 17 are in contact with the contact surface 61 of the lens fixing plate 6. Thereby, the positions and orientations of the slit portions 121 and 122 can be determined, and it is easy to make the first light-shielding plate 14 parallel to the optical axis of the lens array 7 when viewed from the sub-scanning direction (Y-axis direction).

[0069] Next, Figures 8A - 8C the details of the second slit portion 122 will be described. Figures 8A - 8C is an external view of the second slit portion 122 included in the image reading device 101 according to Embodiment 1 of the present disclosure, Figure 8Ais a perspective view of the second slit portion 122 as viewed from the side of the image sensor 11, Figure 8B is a perspective view of the second slit portion 122 as viewed from the side of the lens array 7, Figure 8C is a perspective view of the second slit portion 122 as viewed from the side of the gap 13.

[0070] As Figures 8A - 8C shown, in the second slit portion 122, side plates 15 are provided on both sides of the first light-shielding plate 14 in the sub-scanning direction (Y-axis direction), holding the first light-shielding plate 14 and the second light-shielding plate 19. That is, a plurality of first light-shielding plates 14 at both ends in the sub-scanning direction (Y-axis direction) are held by the side plates 15, and the first light-shielding plates 14 and the single second light-shielding plate 19 are arranged parallel to each other in the main scanning direction (X-axis direction) with a certain interval therebetween. On the side of the lens array 7 of the side plates 15 of the second slit portion 122, protrusions 16 and 17 are provided in the same manner as in the first slit portion 121.

[0071] The protrusions 16 and 17 of the second slit portion 122 have the same structure as the protrusions 16 and 17 of the first slit portion 121, and have the same functions and effects.

[0072] In the second slit portion 122, the second light-shielding plate 19 has a cutout portion 20. That is, the position (lower end) of the end portion on the side of the image sensor 11 in the optical axis direction (Z-axis direction) is on the side of the lens array 7 (upper side) relative to the first light-shielding plate 14. In other words, the end portion of the second light-shielding plate 19 facing the image sensor 11 is closer to the lens array 7 than the first light-shielding plate 14. The second light-shielding plate 19 is only applied to the light-shielding plate at either end in the main scanning direction (X-axis direction) among the light-shielding plates of the second slit portion 122. The other light-shielding plate including the light-shielding plate at the other end of the second slit portion 122 is the first light-shielding plate 14 that does not have the cutout portion 20.

[0073] In addition, in the case where only one slit portion is provided for one lens array 7, only one third slit portion is provided for one lens array 7. The third slit portion provided only one for one lens array 7 has the second light-shielding plates 19 at both ends in the main scanning direction (X-axis direction). The light-shielding plate between both ends in the main scanning direction (X-axis direction) of the third slit portion is the first light-shielding plate 14 that does not have the cutout portion 20. In addition, including the third slit portion, the slit portion having at least one second light-shielding plate 19 is sometimes collectively referred to as the second slit portion.

[0074] The first slit portion 121, the second slit portion 122, and the third slit portion are resin molded products. Since the shapes of the first slit portion 121, the second slit portion 122, and the third slit portion are different from each other, different molding dies are used respectively. In addition, when a plurality of slit portions 12 are provided for one lens array 7, the first slit portion 121 is provided at a position where the adjacent lens array 7 does not exist. Further, when three or more slit portions 12 are provided with respect to one lens array 7, the first slit portion 121 is also provided at a position that is not at both ends of one lens array 7.

[0075] In any of the first slit portion 121, the second slit portion 122, and the third slit portion, each first light shielding plate 14 has the same plate thickness. In addition, each first light shielding plate 14 and each second light shielding plate 19 have the same plate thickness.

[0076] Figure 9 is from Figure 6 A perspective view of the slit portion 12 and the lens array 7 as viewed from the B side (image sensor 11 side) shown in the figure. Figure 10 is from Figure 9 A bottom view of the lens arrays 71 and 72 to which the slit portion 12 is attached as viewed from the direction C shown in the figure. As Figure 9 , Figure 10 shown, a plurality of through optical paths 18 are formed in the first slit portion 121 along the main scanning direction (X-axis direction), and the through optical path 18 is a region surrounded by the first light shielding plate 14 and the side plate 15 that face each other. A plurality of through optical paths 18 are formed in the second slit portion 122 along the main scanning direction (X-axis direction), and the through optical path 18 is a region surrounded by the first light shielding plate 14 and the side plate 15 that face each other. In addition, a through optical path 21 is formed at one end of the second slit portion 122 in the main scanning direction (X-axis direction), and the through optical path 21 is a region surrounded by the first light shielding plate 14, the second light shielding plate 19, and the side plate 15. The center lines of these through optical paths 18 and the through optical path 21 preferably coincide with the optical axes of the lens bodies 41 respectively.

[0077] Preferably, the center line of the through optical path 21 at one end of the second slit portion 122 coincides with the optical axis of the lens body 41 of the lens arrays 71 and 72 that is closest to the gap 13. The first slit portion 121 is arranged on the other end side of the second slit portion 122 with a quantity that leaves the optical path of one lens body 41 empty.

[0078] The first light shield 14 is disposed between the lens array 7 and the image sensor 11, and is respectively disposed at the position where one lens body 41 is in contact with an adjacent lens body 41. The first light shield 14 has an end on the image sensor 11 side that is at a predetermined distance from the surface of the lens array 7 on the image sensor 11 side in the optical axis direction (Z-axis direction), and separates the light passing through each lens body 41. More specifically, the first light shield 14 does not completely isolate the light passing through each lens body 41, but generates a state where the optical path of the light passing through one lens body 41 and the optical path of the light passing through the adjacent lens body 41 overlap on the surface of the image sensor 11 on the lens array 7 side, and the length of the main scanning direction (X-axis direction) of the overlapping region is a determined length. In addition, the length of the main scanning direction of the region where the optical paths of the light passing through the lens body 41 overlap on the surface of the image sensor 11 on the lens array 7 side is also referred to as the field repetition degree. In addition, separating the light passing through the lens body 41 in a state where the field is repeated with a determined field repetition degree is also expressed as separating the optical paths of the light passing through the lens body 41.

[0079] The second light shield 19 restricts the position of the end of the lens array 7 in the main scanning direction (X-axis direction) on the side of the gap 13 of the lens array 7 in the main scanning direction (X-axis direction), that is, the optical path of the lens body 41 at the position closest to the gap 13. The position of the second light shield 19 on the image sensor 11 side in the direction along the optical axis is closer to the lens array 7 than the first light shield 14. That is, the end of the second light shield 19 facing the image sensor 11 is closer to the lens array 7 than the first light shield 14. In other words, in the optical axis direction (Z-axis direction), the distance from the surface of the lens array 7 on the image sensor 11 side to the end of the second light shield 19 on the image sensor 11 side is shorter than the distance from the surface of the lens array 7 on the image sensor 11 side to the end of the first light shield 14 on the image sensor 11 side. The field region of the lens body 41 restricted by such a second light shield 19 overlaps with the field region of the lens body 41 adjacent to the lens array 7 on the surface of the image sensor 11 across the gap 13. More specifically, in a state where the optical paths of the light passing through the lens body 41 closest to the gap 13 of the lens array 71 and the optical paths of the light passing through the lens body 41 closest to the gap 13 of the lens array 72 are repeated with a determined field repetition degree, the second light shield 19 separates the light passing through the two lens bodies 41 closest to the gap 13. That is, a state is generated where the length of the main scanning direction (X-axis direction) of the region where the optical paths of the light passing through the two lens bodies 41 closest to the gap 13 overlap is a determined length.

[0080] Use Figure 11 、 Figure 12 To illustrate the effect of the second light shield 19. Figure 11It is a schematic diagram for explaining the problems that occur in the case where the second light shielding plate 19 of the image reading device 101 according to Embodiment 1 of the present disclosure is not provided. Figure 12 It is a schematic diagram for explaining the effect of the second light shielding plate 19 of the image reading device 101 according to Embodiment 1 of the present disclosure. Figure 11 It shows the case where only the first light shielding plate 14 is provided in the lens array 7. Figure 12 It shows the case where the present disclosure is applied and the light shielding plate closest to the gap 13 in the lens array 7 is the second light shielding plate 19.

[0081] Figure 11 , 12 The interval Δg between the adjacent slit portions 12 and the interval Δd of the gap 13 between the lens arrays 71 and 72 shown are determined by assuming a low temperature during the use or storage of the image reading device 101 during assembly. Specifically, the interval Δg between the adjacent slit portions 12 is set to a width capable of absorbing the difference in the contraction lengths caused by the difference in the linear expansion coefficients of the lens arrays 71 and 72 and the lens fixing plate 6. In addition, the interval Δd of the gap 13 between the lens arrays 71 and 72 needs to leave at least an interval for the difference in the lengths in the main scanning direction (X-axis direction) of the contraction of the lens arrays 71 and 72 due to temperature reduction and the length in the main scanning direction (X-axis direction) of the contraction of the lens fixing plate 6 due to temperature reduction plus the thickness t of the light shielding plate.

[0082] As Figure 11 shown, a first light shielding plate 14 is provided on the surface of the lens arrays 71 and 72 formed by arranging a plurality of lens bodies 41 with a diameter d that faces the light receiving surface 22 of the image sensor 11. The thickness of the first light shielding plate 14 is set to t. The distance between the end portion on the light receiving surface 22 side in the optical axis direction (Z-axis direction) of the first light shielding plate 14 and the surface on the light receiving surface 22 side of the lens arrays 71 and 72 is S1. The light focused by the lens body 41 exits from the lens body 41, and the maximum value (field angle) of the angle at which the optical path expands with respect to the optical axis is limited to θ1 by the first light shielding plate 14. The field angle θ1 varies according to the distance S1. When the distance S1 becomes larger, the field angle θ1 becomes smaller. When the distance S1 becomes smaller, the field angle θ1 becomes larger. When the field angle θ1 is narrowed by the first light shielding plate 14, the overlap of the optical paths of the light passing through the adjacent lens bodies 41 becomes smaller. By reducing the overlap of the optical paths of the light passing through the adjacent lens bodies 41, the distance W can be increased. Generally, the smaller the field angle θ1 is reduced, the greater the improvement effect of the distance W is. In addition, the distance W corresponds to the depth of field.

[0083] However, the viewing angle on the side of the lens body 41 closest to the gap 13 of the lens array is also limited to the viewing angle θ1 by the first light-shielding plate 14 at the distance S1 in the same manner. Therefore, the viewing areas of the respective lens bodies 41 in the portions other than the gap 13 overlap on the light-receiving surface 22 of the image sensor 11. On the other hand, in the gap 13 portion provided between the lens arrays 71 and 72, the viewing areas of the respective lens bodies 41 across the gap 13 do not overlap on the light-receiving surface 22 of the image sensor 11. When the viewing areas of the respective lens bodies 41 do not overlap on the light-receiving surface 22 of the image sensor 11, the read image becomes discontinuous at the portions where the viewing areas do not overlap.

[0084] In the present disclosure, as Figure 12 shown, a second light-shielding plate 19 is disposed on the side of the gap 13 of the lens body 41 closest to the gap 13 of the lens arrays 71 and 72. The thickness of the second light-shielding plate 19 is set to t. The distance between the end on the image sensor side in the optical axis direction (Z-axis direction) of the second light-shielding plate 19 and the image sensor side surface of the lens arrays 71 and 72 is set to S2. The relationship between the distance S1 and the distance S2 is represented by S1 > S2. Therefore, the viewing angle θ2 on the side of the gap 13 based on the second light-shielding plate 19 is larger than the viewing angle θ1 limited by the first light-shielding plate 14.

[0085] In order for the read image of the image reading device 101 to be continuous between the lens array 71 and the lens array 72, the viewing areas of two adjacent lens bodies 41 across the gap 13 need to overlap on the light-receiving surface 22 of the image sensor 11. The distance S2 of the second light-shielding plate 19 is determined to be a distance at which the viewing areas of the respective lens bodies 41 limited to the viewing angle θ2 can overlap with a predetermined viewing overlap degree on the light-receiving surface 22 of the image sensor 11.

[0086] In order for the viewing area of the lens body 41 limited to the viewing angle θ2 to overlap on the light-receiving surface 22 of the image sensor 11, it is sufficient to satisfy the relationship shown in the following formula (1). It is only necessary to determine the distance S2 when the viewing angle θ2 satisfies the formula (1).

[0087] W·tan(θ2)≥d / 2+Δd / 2 (1)

[0088] In addition, as described above, the gap width Δd is determined to be a width capable of absorbing the difference in contraction lengths caused by the difference in the linear expansion coefficients of the lens arrays 71 and 72 and the lens fixing plate 6 when the environmental temperature decreases. In contrast, when the environmental temperature rises, the interval Δd of the gap 13 expands. Therefore, it is preferable to determine the interval Δd of the gap 13 and the distance S2 to be values at which the viewing areas in the light-receiving surface 22 of the image sensor 11 can overlap even when the environmental temperature rises.

[0089] Therefore, by applying the present disclosure, even in a usage environment capable of withstanding ambient temperature changes, when the depth of field is set to a predetermined value and a plurality of lens arrays 7 arranged with a gap 13 in the main scanning direction (X-axis direction) are used, an image reading device 101 in which image reading between the lens arrays 7 becomes discontinuous can be obtained.

[0090] In addition, the lengths in the main scanning direction (X-axis direction) of the first repeating region where the visual field regions of the lens bodies 41 restricted by the first light shielding plate 14 overlap and the second repeating region where the visual field regions of the lens bodies 41 restricted by the second light shielding plate 19 overlap may also be the same as each other. Here, the first repeating region is a region that overlaps in the light receiving surface 22 (the surface on the lens array side) of the image sensor 11 after the optical path of the light passing through two adjacent lens bodies 41 is restricted to a visual field angle θ1 by the first light shielding plate 14. In addition, the second repeating region is a region that overlaps in the light receiving surface 22 of the image sensor 11 after the optical path of the light passing through two adjacent lens bodies 41 is restricted to a visual field angle θ2 by the second light shielding plate 19. That is, the visual field repetition degree of the lens bodies 41 restricted to the visual field angle θ1 may be made the same as the visual field repetition degree of the lens bodies 41 restricted to the visual field angle θ2. Thereby, the intensity difference of the light between the first repeating region without the gap 13 and the second repeating region with the gap 13 can be reduced.

[0091] As described above, the image reading device 101 according to Embodiment 1 includes: a plurality of lens arrays 7 arranged with gaps 13 therebetween in the main scanning direction, each lens array 7 having a plurality of lens elements 41 arranged in the main scanning direction; and an image sensor 11 that receives the light focused by the lens elements. The image reading device 101 further includes a plurality of slit portions 12, one or more of which are provided for one lens array 7 between the lens array 7 and the image sensor 11 and arranged in the main scanning direction. The plurality of slit portions 12 include a second slit portion 122, which is a slit portion having a first light shielding plate 14 and a second light shielding plate 19. The first light shielding plate 14 separates the optical path of the light that has passed through one lens element 41 from the optical path of the light that has passed through an adjacent lens element 41, and the second light shielding plate 19 restricts the optical path of the light that has passed through the lens element 41 closest to the gap 13 on the gap 13 side in the main scanning direction. The second light shielding plate 19 is located closer to the lens array 7 side than the first light shielding plate at the position on the image sensor 11 side in the direction along the optical axis. As a result, the visual field region of the lens element 41 representing the expansion of the restricted optical path overlaps with the visual field region of the lens element 41 adjacent across the gap 13 on the surface of the image sensor 11 on the lens array 7 side. It is characterized in that when a plurality of slit portions 12 are provided for one lens array 7, the plurality of slit portions 12 further include a first slit portion 121, which is a slit portion including only the first light shielding plate 14. Thus, by providing the slit portion 12 between the lens array 7 and the image sensor 11 to restrict the visual field region of the lens element 41, even when the depth of field is set to a determined value and a plurality of lens arrays 7 arranged with gaps 13 therebetween in the main scanning direction are used, it is possible to prevent the read image from becoming discontinuous at the gap portions between the lens arrays 7.

[0092] Embodiment 2.

[0093] Hereinafter, with reference to FIGS. 13 to Figure 16 the image reading device 102 according to Embodiment 2 will be described. The second slit portion 122 included in the image reading device 101 according to Embodiment 1 is a resin molded product. On the other hand, the second slit portion 124 included in the image reading device 102 according to Embodiment 2 combines the first slit portion 123 included in the image reading device 102 according to Embodiment 2 and the second light shielding plate 24. Other structures are substantially the same as those in Embodiment 1. Hereinafter, the same reference numerals are given to the structures that are the same as or equivalent to those described in Embodiment 1 above, and the description of these structures will not be repeated.

[0094] Figure 13A , Figure 13B is an external view of the first slit portion 123 of the image reading device 102 according to Embodiment 2 of the present disclosure, Figure 13A is a perspective view observed from the image sensor 11 side,Figure 13B This is a perspective view observed from the side of the lens array 7. As Figure 13A , Figure 13B shown, four concave portions 23 are formed at the main scanning direction ends of the side plates 15 of the first slit portion 123 in the second embodiment. The length of the concave portion 23 in the optical axis direction (Z-axis direction) is shorter than that of the first light shielding plate 14.

[0095] Figure 14 This is a perspective view of the second slit portion 124 of the image reading device 102 according to the second embodiment of the present disclosure observed from the side of the image sensor 11. As Figure 14 shown, the second light shielding plate 24 has a main body portion parallel to the first light shielding plate 14 and side portions 241 that are bent on both sides of the main body portion. The second slit portion 124 combines the first slit portion 123 and the second light shielding plate 24 by fixing the side portions 241 to the concave portions 23 with an adhesive 25. The side portions 241 of the second light shielding plate 24 are only embedded and fixed in the concave portions 23 at one end of the side plate 15.

[0096] Figure 15 This is a perspective view of the lens arrays 71 and 72 to which the slit portions 123 and 124 of the image reading device 102 according to the second embodiment of the present disclosure are pasted. Figure 16 This is a top view observed from side D Figure 15 of. As Figure 15 , Figure 16 shown, the first slit portion 123 and the second slit portion 124 are pasted on the side of the image sensor 11 of the lens arrays 71 and 72. The center line of the through optical path 26 formed by the first light shielding plate 14, the second light shielding plate 24, and the side plate 15 coincides with the optical axis of the lens body 41 closest to the gap 13 of the lens array 7.

[0097] As described above, by previously providing the concave portions 23 in the molded product of the first slit portion 123 and pasting the second light shielding plate 24 as needed, it is not necessary to prepare a dedicated molding die for the second slit portion 124. Thereby, the die cost and the number of component types can be reduced.

[0098] Embodiment 3.

[0099] Hereinafter, with reference to Figure 17A , Figures 17B to 20 the image reading device 103 of the third embodiment will be described. The second slit portion 122 included in the image reading device 101 of the first embodiment is a resin molded product. On the other hand, the second slit portion 126 included in the image reading device 103 of the third embodiment combines the first slit portion 125 and the second light shielding plate 28. Other structures are substantially the same as those in the first embodiment. Hereinafter, the same reference numerals will be given to the structures that are the same as or equivalent to the structures described in the above first embodiment, and the description of these structures will not be repeated.

[0100] Figure 17A and Figure 17B is an external view of the first slit portion 125 of the image reading device 103 according to Embodiment 3 of the present disclosure, Figure 17A is a perspective view observed from the side of the image sensor 11, Figure 17B is a perspective view observed from the side of the lens array 7. As Figure 17A 、 Figure 17B shown, four convex portions 27 are provided at the main scanning direction ends of the side plates 15 of the first slit portion 125 in Embodiment 3. The convex portion 27 is a base for mounting the second light shielding plate 28 manufactured by stamping or injection molding. The length of the convex portion 27 in the optical axis direction (Z-axis direction) is shorter than that of the first light shielding plate 14.

[0101] Figure 18 is a perspective view of the second slit portion 126 of the image reading device 103 according to Embodiment 3 of the present disclosure observed from the side of the image sensor 11. As Figure 18 shown, the second light shielding plate 28 has side portions 281. The first slit portion 125 and the second light shielding plate 28 are combined by fixing the side portions 281 to the convex portions 27 with an adhesive 29 in the second slit portion 126.

[0102] Figure 19 is a perspective view of the lens arrays 71 and 72 to which the slit portions 125 and 126 included in the image reading device 103 according to Embodiment 3 of the present disclosure are attached. Figure 20 is from Figure 19 is a bottom view of the lens arrays 71 and 72 to which the slit portions 125 and 126 are attached observed from the direction E shown. The first slit portion 125 and the second slit portion 126 are attached to the side of the image sensor 11 of the lens arrays 71 and 72. The center line of the through optical path 30 formed by the first light shielding plate 14, the second light shielding plate 28, and the side plate 15 coincides with the optical axis of the lens body 41 closest to the gap 13.

[0103] As described above, by previously providing the convex portions 27 on the molded product of the first slit portion 125 and attaching the second light shielding plate 28 as needed, it is not necessary to prepare a molding die dedicated to the second slit portion 126. Accordingly, the die cost and the number of component types can be reduced.

[0104] In addition, in Embodiments 1 to 3, as an example, an example in which the slit portions 12 are arranged in the main scanning direction (X-axis direction) with an interval corresponding to the amount of one optical path of the lens body 41 vacant is shown, but they may be arranged without a gap.

[0105] In addition, in Embodiments 1 to 3, as an example, an example in which the lens array 7 and the slit portions 12 are arranged in a line in the main scanning direction (X-axis direction) is shown, but they may be arranged in multiple lines.

[0106] In addition, in Embodiments 1 to 3, as an example, a case where the slit portion 12 has side plates 15 and the first light shielding plate 14 and the second light shielding plate 19 are held by the side plates 15 from both sides in the sub-scanning direction (Y-axis direction) is shown. However, the side plates 15 may also hold the light shielding plates only from one side in the sub-scanning direction (Y-axis direction). Further, the side plates 15 may be omitted, and the first light shielding plate 14 and the second light shielding plate 19 may be fixed to the holding portion 42 of the lens array 7.

[0107] In addition, in Embodiments 1 to 3, as an example, a case where a plurality of slit portions 12 are arranged in one lens array 7 is shown. However, one slit portion 12 may be provided in one lens array 7. The third slit portion in the case where one slit portion 12 is arranged in one lens array 7 is provided with second light shielding plates 19 at both ends.

[0108] In addition, in Embodiments 2 and 3, as an example, a case where the side portions 241 and 281 of the second light shielding plates 24 and 28 are fixed to the concave portions 23 and the convex portions 27 provided on the side plates 15 of the first slit portions 123 and 125 is shown. However, as long as it is a structure capable of fixing the side portions of the second light shielding plate to the ends of the side plates 15 of the first slit portions 123 and 125, other structures may also be used.

[0109] In addition, the structures shown in the above Embodiments 1 to 3 represent an example of the content of the present disclosure, and a plurality of embodiments can be freely combined. In addition, it can also be combined with other known technologies. In addition, a part of the structure may be omitted or changed without departing from the gist of the present disclosure.

[0110] Hereinafter, the respective aspects of the present disclosure are collectively described as appendices.

[0111] (Appendix 1) An image reading apparatus, comprising:

[0112] A plurality of lens arrays arranged at intervals in the main scanning direction, each of the lens arrays having a plurality of lens bodies arranged in the main scanning direction;

[0113] An image sensor that receives light focused by the lens bodies; and

[0114] A plurality of slit portions, one or more of which are provided for one of the lens arrays between the lens array and the image sensor and are arranged in the main scanning direction,

[0115] The plurality of slit portions include a second slit portion which is the slit portion having a first light-shielding plate and a second light-shielding plate. The first light-shielding plate separates the optical path of the light that has passed through one of the lens bodies from the optical path of the light that has passed through an adjacent lens body. The second light-shielding plate restricts the optical path of the light that has passed through the lens body closest to the gap on the gap side in the main scanning direction, and the position on the image sensor side along the direction of the optical path is closer to the lens array side than the first light-shielding plate, such that the visual field region of the lens body representing the expansion of the restricted optical path overlaps the visual field region of the lens body adjacent across the gap on the surface of the image sensor on the lens array side.

[0116] In the case where a plurality of the slit portions are provided with respect to one of the lens arrays, the plurality of slit portions further include a first slit portion which is the slit portion including only the first light-shielding plate.

[0117] (Supplementary Note 2) An image reading device, comprising:

[0118] A plurality of lens arrays arranged with a gap in the main scanning direction, each of the lens arrays having a plurality of lens bodies arranged in the main scanning direction;

[0119] An image sensor that receives the light focused by the lens body; and

[0120] A plurality of slit portions, one or more of which are provided with respect to one of the lens arrays between the lens array and the image sensor and arranged in the main scanning direction,

[0121] The plurality of slit portions include a second slit portion having a first light-shielding plate and a second light-shielding plate. The first light-shielding plate separates the optical path of the light that has passed through one of the lens bodies from the optical path of the light that has passed through an adjacent lens body. The second light-shielding plate restricts the optical path of the light that has passed through the lens body closest to the gap in the direction toward the gap, and the end portion facing the image sensor is closer to the lens array than the first light-shielding plate.

[0122] (Supplementary Note 3) The image reading device according to Supplementary Note 2, wherein

[0123] In the case where a plurality of the slit portions are provided with respect to one of the lens arrays, the plurality of slit portions further include a first slit portion which includes only the first light-shielding plate.

[0124] (Supplementary Note 4) The image reading device according to any one of Supplementary Notes 1 to 3, wherein

[0125] In a case where one of the slit portions is provided relative to one of the lens arrays, the plurality of slit portions include a third slit portion that has the second light-shielding plate at both ends in the main scanning direction and has the first light-shielding plate between the both ends.

[0126] (Supplementary Note 5) The image reading device according to any one of Supplementary Notes 1 to 4, wherein

[0127] Light focused by the lens body whose optical path is restricted by the second light-shielding plate exits from the lens body. When a viewing angle that represents the maximum value of the angle by which the optical path extends relative to the optical axis of the lens body is set as θ2, a distance between the light-emitting surface of the lens body and the surface of the image sensor on the lens array side is set as W, a diameter of the lens body is set as d, and a width of the gap is set as Δd, the viewing angle θ2, the distance W, the diameter d, and the width Δd satisfy the following relationship:

[0128] W·tan(θ2)≥d / 2+Δd / 2.

[0129] (Supplementary Note 6) The image reading device according to any one of Supplementary Notes 1 to 5, wherein

[0130] A length in the main scanning direction of a first overlapping region where the viewing regions of two lens bodies restricted by the respective first light-shielding plates from blocking the optical path overlap on the surface of the image sensor on the lens array side is the same as a length in the main scanning direction of a second overlapping region where the viewing regions of two lens bodies restricted by the respective second light-shielding plates from blocking the optical path overlap on the surface of the image sensor on the lens array side.

[0131] (Supplementary Note 7) The image reading device according to any one of Supplementary Notes 1 to 6, wherein

[0132] The slit portion has side plates that extend in the main scanning direction between the lens array and the image sensor and are provided on both sides in the sub-scanning direction of the first light-shielding plate to hold the first light-shielding plate.

[0133] (Supplementary Note 8) The image reading device according to Supplementary Note 7, wherein

[0134] The side plates of the second slit portion hold the first light-shielding plate and the second light-shielding plate.

[0135] (Supplementary Note 9) The image reading device according to Supplementary Note 7, wherein

[0136] The second slit portion bonds a side portion of the second light-shielding plate that protrudes in the main scanning direction to an end in the main scanning direction of the side plate.

[0137] (Supplemental Note 10) The image reading device according to Supplemental Note 9, wherein,

[0138] The second slit portion adheres the side portion to a concave portion or a convex portion provided at an end of the side plate in the main scanning direction.

[0139] (Supplemental Note 11) The image reading device according to any one of Supplemental Notes 1 to 10, wherein,

[0140] The plurality of slit portions provided with respect to one lens array are arranged at intervals of an amount corresponding to one optical path of the lens body.

[0141] (Supplemental Note 12) The image reading device according to any one of Supplemental Notes 1 to 11, wherein,

[0142] The ends of the first light shielding plate and the second light shielding plate of the slit portion on the lens array side are in contact with the surface of the lens array on the image sensor side.

[0143] (Supplemental Note 13) The image reading device according to any one of Supplemental Notes 7 to 10, wherein,

[0144] The slit portion includes one or more protruding portions protruding from a part of the end surface of the side plate on the lens array side.

[0145] (Supplemental Note 14) The image reading device according to Supplemental Note 13, wherein,

[0146] The slit portion is fixed by adhering the protruding portion to the lens array with an adhesive.

[0147] (Supplemental Note 15) The image reading device according to Supplemental Note 13 or 14, wherein,

[0148] The position and orientation of the slit portion are determined by bringing the protruding portion into contact with the surface of the lens fixing plate that fixes the lens array on the image sensor side.

[0149] (Supplemental Note 16) The image reading device according to any one of Supplemental Notes 1 to 15, wherein,

[0150] The optical axis of the lens body coincides with a straight line passing through the center of the light receiving portion of the image sensor and perpendicular to the light receiving surface of the image sensor.

[0151] (Supplemental Note 17) The image reading device according to any one of Supplemental Notes 7 to 10, wherein,

[0152] The optical axis of the lens body coincides with the center line of the through optical path surrounded by the first light shielding plate and the side plate which face each other.

[0153] (Supplementary Note 18) The image reading device according to any one of Supplementary Notes 7 to 10, wherein

[0154] The optical axis of the lens body coincides with the center line of the through optical path surrounded by the first light shielding plate, the second light shielding plate, and the side plate.

[0155] The present disclosure can implement various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. In addition, the above embodiments are used to illustrate the present disclosure rather than to limit the scope of the present disclosure. That is, the scope of the present disclosure is represented by the claims, rather than by the embodiments. Moreover, various modifications implemented within the meaning of the claims and the equivalent disclosure are regarded as being within the scope of the present disclosure.

[0156] This application is based on Japanese Patent Application No. 2022-190328 filed on November 29, 2022. The entire specification, claims, and drawings of Japanese Patent Application No. 2022-190328 are incorporated herein by reference.

[0157] Explanation of Reference Numerals

[0158] 101, 102, 103... Image reading device; 1... Frame; 2... Transparent body; 3... Frame side plate; 5... Substrate support plate; 6... Lens fixing plate; 61... Contact surface; 7, 71, 72... Lens array; 41... Lens body; 42... Holding portion; 8... Sensor driving substrate; 9... Sensor substrate; 11... Image sensor; 12... Slit portion; 121, 123, 125... First slit portion; 122, 124, 126... Second slit portion; 13... Gap; 14... First light shielding plate; 15... Side plate; 16, 17... Protrusion; 18, 21, 26, 30... Through optical path; 19, 24, 28... Second light shielding plate; 20... Cutout portion; 23... Recess; 25, 29... Adhesive; 27... Convex portion; 241, 281... Side portion.

Claims

1. An image reading device, characterized in that, Comprising: A plurality of lens arrays arranged with gaps therebetween in the main scanning direction, each of the lens arrays having a plurality of lens bodies arranged in the main scanning direction; An image sensor that receives light focused by the lens bodies; And A plurality of slit portions, one or more of which are provided for one of the lens arrays between the lens array and the image sensor and arranged in the main scanning direction, The plurality of slit portions include a second slit portion which is the slit portion having a first light shielding plate and a second light shielding plate, the first light shielding plate separating the optical path of the light passing through one of the lens bodies from the optical path of the light passing through the adjacent lens body, the second light shielding plate restricting the optical path of the light passing through the lens body closest to the gap on the gap side in the main scanning direction, and the position on the image sensor side in the direction of the optical path being closer to the lens array side than the first light shielding plate, so that the field of view region of the lens body representing the expansion of the restricted optical path overlaps with the field of view region of the lens body adjacent across the gap on the surface of the image sensor on the lens array side; When a plurality of the slit portions are provided for one of the lens arrays, the plurality of slit portions further include a first slit portion which is the slit portion including only the first light shielding plate.

2. An image reading device, characterized in that, Comprising: A plurality of lens arrays arranged with gaps therebetween in the main scanning direction, each of the lens arrays having a plurality of lens bodies arranged in the main scanning direction; An image sensor that receives light focused by the lens bodies; And A plurality of slit portions, one or more of which are provided for one of the lens arrays between the lens array and the image sensor and arranged in the main scanning direction, The plurality of slit portions include a second slit portion having a first light shielding plate and a second light shielding plate, the first light shielding plate separating the optical path of the light passing through one of the lens bodies from the optical path of the light passing through the adjacent lens body, the second light shielding plate restricting the optical path of the light passing through the lens body closest to the gap in the direction towards the gap, and the end portion facing the image sensor being closer to the lens array than the first light shielding plate.

3. The image reading device according to claim 2, characterized in that When a plurality of the slit portions are provided for one of the lens arrays, the plurality of slit portions further include a first slit portion which includes only the first light shielding plate.

4. The image reading device according to any one of claims 1 to 3, characterized in that When one of the slit portions is provided for one of the lens arrays, the plurality of slit portions include a third slit portion which is the slit portion having the second light shielding plates at both ends in the main scanning direction and the first light shielding plate between the two ends.

5. The image reading device according to any one of claims 1 to 4, characterized in that Light focused by the lens body whose optical path is restricted by the second light-shielding plate exits from the lens body. When the viewing angle θ2, which represents the maximum value of the angle by which the optical path expands with respect to the optical axis of the lens body, is set, the distance W between the exit surface of the lens body and the surface of the lens array side of the image sensor is set, the diameter d of the lens body is set, and the width Δd of the gap is set, the viewing angle θ2, the distance W, the diameter d, and the width Δd satisfy the following relationship: W·tan(θ2)≥d / 2+Δd / 2.

6. The image reading device according to any one of claims 1 to 5, characterized in that: The length in the main scanning direction of the first overlapping region where the viewing regions of the two lens bodies restricted by each of the first light-shielding plates blocking the optical path overlap on the surface of the lens array side of the image sensor is the same as the length in the main scanning direction of the second overlapping region where the viewing regions of the two lens bodies restricted by each of the second light-shielding plates blocking the optical path overlap on the surface of the lens array side of the image sensor.

7. The image reading device according to any one of claims 1 to 6, characterized in that: The slit portion has side plates that extend in the main scanning direction between the lens array and the image sensor and are provided on both sides in the sub-scanning direction of the first light-shielding plate to hold the first light-shielding plate.

8. The image reading device according to claim 7, characterized in that: The side plates of the second slit portion hold the first light-shielding plate and the second light-shielding plate.

9. The image reading device according to claim 7, characterized in that: The second slit portion bonds the side portion protruding in the main scanning direction of the second light-shielding plate to the end portion in the main scanning direction of the side plate.

10. The image reading device according to claim 9, characterized in that: The second slit portion bonds the side portion to a concave portion or a convex portion provided at the end portion in the main scanning direction of the side plate.

11. The image reading device according to any one of claims 1 to 10, characterized in that: A plurality of the slit portions provided with respect to one lens array are arranged at intervals leaving an amount corresponding to one optical path of the lens body.

12. The image reading device according to any one of claims 1 to 11, characterized in that: The ends on the lens array side of the first light-shielding plate and the second light-shielding plate of the slit portion are in contact with the surface of the lens array on the image sensor side.

13. The image reading device according to any one of claims 7 to 10, characterized in that: The slit portion includes one or more protruding portions protruding from a part of the end surface on the lens array side of the side plate.

14. The image reading device according to claim 13, characterized in that: The slit portion is fixed by bonding the protruding portion to the lens array with an adhesive.

15. The image reading device according to claim 13 or 14, characterized in that: The slit portion determines the position and orientation thereof by bringing the protrusion portion into contact with the surface on the image sensor side of the lens fixing plate that fixes the lens array.

16. The image reading device according to any one of claims 1 to 15, characterized in that the optical axis of the lens body coincides with a straight line passing through the center of the light receiving portion of the image sensor and perpendicular to the light receiving surface of the image sensor.

17. The image reading device according to any one of claims 7 to 10, characterized in that the optical axis of the lens body coincides with the center line of the through optical path surrounded by the first light shielding plate and the side plate that face each other.

18. The image reading device according to any one of claims 7 to 10, characterized in that the optical axis of the lens body coincides with the center line of the through optical path surrounded by the first light shielding plate, the second light shielding plate, and the side plate.

Images