This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2023-023608 filed Feb. 17, 2023.
The present disclosure relates to an optical device, an image reading unit, and an image forming apparatus.
Japanese Unexamined Patent Application Publication No. 2007-43360 describes an image sensor having a structure including a rodlike light source that irradiates a to-be-read image with light, a slitted hood that captures light reflected off the to-be-read image through a slit, an image-forming optical system that converges light that has passed through the slit, and a light receiving element that receives light that has passed through the image-forming optical system, and a housing that accommodates the light source, the slitted hood, the image-forming optical system, and the light receiving element. A thin metal hood is used as the slitted hood.
An optical device includes a restriction member and a holding member. The restriction member includes an opening that extends in one direction, and that allows part of reflected light reflected off a target object to pass through it while restricting the other part of the reflected light. The holding member holds an optical member that extends in one direction and that transmits the reflected light that has passed through the opening.
When the restriction member having the opening extending in one direction is formed from a resin material, the opening may have its width (“opening width”, below) at a center portion in one direction narrower than the opening width at end portions in the direction due to, for example, die shrinkage.
Aspects of non-limiting embodiments of the present disclosure relate to reduction of narrowing the opening width at the center portion in one direction with respect to the opening width at end portions in the direction compared to a case where a restriction member and a holding member that holds an optical member come into contact with each other simply in a direction in which reflected light propagates.
Aspects of certain non-limiting embodiments of the present disclosure overcome the above disadvantages and/or other disadvantages not described above. However, aspects of the non-limiting embodiments are not required to overcome the disadvantages described above, and aspects of the non-limiting embodiments of the present disclosure may not overcome any of the disadvantages described above.
An optical device according to a first aspect of the present disclosure includes: a restriction member that restricts part of reflected light from a target object, the restriction member being formed from resin, the restriction member having an opening and a hole, the opening extending in a first direction crossing a propagation direction of the reflected light and formed at an upstream end in the propagation direction, the hole extending through the restriction member in the propagation direction; an optical member that transmits the reflected light that has passed through the opening; and a correction member that holds the optical member, and that comes into contact with part of an inner circumferential surface of the hole to correct a width of the opening.
Exemplary embodiments of the present disclosure will be described in detail based on the following figures, wherein:
Examples of an image reading device, an image reading unit, and an image forming apparatus according to an exemplary embodiment of the present disclosure are described with reference to
In the drawings, arrow H indicates an apparatus height direction (vertical direction), arrow W indicates an apparatus width direction (horizontal direction), and arrow D indicates an apparatus depth direction (horizontal direction). The apparatus height direction, the apparatus width direction, and the apparatus depth direction are perpendicular to each other. The apparatus height direction may be described as a height direction.
As illustrated in
The container 14 includes a container member 26 that is drawable out to the front in the apparatus depth direction from a housing 10a of the image forming apparatus 10. The container member 26 receives a stack of the sheet members P. The container 14 includes a pick-up roller 30 that dispatches the uppermost one of the sheet members P stacked on the container member 26 to a transport path 28 for the sheet members P.
The transport portion 16 includes multiple transport rollers 32 that transport the sheet members P along the transport path 28.
The image forming portion 20 includes four image forming units 18Y, 18M, 18C, and 18K for yellow (Y), magenta (M), cyan (C), and black (K), respectively. In the following description, the reference signs may be described without Y, M, C, and K when the colors Y, M, C, K are not to be distinguished from one another.
An image forming unit 18 for each color is attachable to and removable from the housing 10a. The image forming unit 18 for each color includes an image carrier 36, a charging roller 38 that electrically charges the surface of the image carrier 36, and an exposure device 42 that emits exposure light to the electrically charged image carrier 36.
The image forming unit 18 for each color also includes a development device 40 that develops an electrostatic latent image formed by the exposure device 42 exposing the electrically charged image carrier 36 to light, into a visible toner image.
The image forming portion 20 also includes an endless transfer belt 22 that rotates in the direction of arrow A in the drawing, and first transfer rollers 44 that each transfer the toner image formed by the image forming unit 18 for the corresponding color to the transfer belt 22. The image forming portion 20 also includes a second transfer roller 46 that transfers the toner images transferred to the transfer belt 22 to the sheet members P, and a fixing device 50 that fixes the toner images to the sheet members P by heating and pressing the sheet members P to which the toner images are transferred. The second transfer roller 46 is an example of a transfer device.
As illustrated in
Above the first transparent plate 62 and the second transparent plate 72, an open/close cover 66 that opens or closes the first transparent plate 62 and the second transparent plate 72 is disposed. The open/close cover 66 accommodates a transport device 64 (that is, an automatic document feeder (ADF)) that transports multiple documents G along a transport path 70 in the open/close cover 66 and allows the documents G to pass a document read position R above the second transparent plate 72.
The housing 60a accommodates an image reading device 100 that reads an image on the document G placed on the first transparent plate 62 and an image on the document G transported by the transport device 64 to the document read position R. The image reading unit 60 includes a driving device 74 that drives the image reading device 100 in the apparatus width direction. The image reading device 100 is an example of an optical device. The image reading device 100 is described below in detail.
As illustrated in
The driving device 74 also includes a motor 80, a driving pulley 84 that drives to rotate with a driving force transmitted from the motor 80, a driven pulley 86 that is driven to rotate, and an endless belt 82 wound around the driving pulley 84 and the driven pulley 86. The driving pulley 84 is attached to a first end of the shaft 76, and the driven pulley 86 is attached to a second end of the shaft 76.
As illustrated in
As illustrated in
In this structure, as illustrated in
In contrast, to read the image on the document G placed on the first transparent plate 62, as illustrated in
Subsequently, the image reading device 100 is described in detail.
The image reading device 100 illustrated in
Except for a case of a special shape, the image reading device 100 is symmetrical with respect to the center in the apparatus width direction, and symmetrical with respect to the center in the apparatus depth direction.
As illustrated in
As illustrated in
The lower housing 240 includes a through-hole 244 to which the condenser 112 is attached, and a container 262 that accommodates the light receiving substrate 102.
The upper housing 200 and the lower housing 240 are described in detail below.
The light guides 110 are formed from a transparent material such as resin or glass. As illustrated in
The light guides 110 each have a center portion in the longitudinal direction fastened by a fastener to the upper housing 200 while allowing both end portions in the longitudinal direction to expand and contract in the apparatus depth direction. The fastener is not illustrated. As illustrated in
The light guides 110 each include a reflection member (not illustrated) extending in the longitudinal direction. The reflection member allows light that is incident on the end surface 110a of the light guide 110 and propagates in the longitudinal direction of the light guide 110 to emerge upward of the condenser 112 (in the direction of arrows B in
As illustrated in
The lens arrays 152 are each formed integrally (with, for example, injection molding) from, for example, polymethyl methacrylate (PMMA), which is a transparent resin material, and are rectangular parallelepiped to extend in the apparatus depth direction. As illustrated in
Each of the lens arrays 152 also includes ridges 154 at both edges of the upper surface 152a in the apparatus width direction, and ridges 156 at both edges of the lower surface 152b in the apparatus width direction. The ridges 154 extend in the apparatus depth direction and protrude upward. The ridges 156 extend in the apparatus depth direction and protrude downward.
Multiple lens surfaces 158 protrude from the upper surface 152a and the lower surface 152b. The lens surfaces 158 protrude from the upper surface 152a or the lower surface 152b by a distance that is smaller than the distance by which the ridges 154 or 156 protrude from the upper surface 152a or the lower surface 152b.
The lens surfaces 158 are staggered to form two rows in the apparatus depth direction (refer to
As illustrated in
As illustrated in
Here, the first lens array 152 indicates the upper lens array 152, or the lens array 152 on the upper side in the
The light-shielding films 162 may be simply formed on the upper surface 152a of the first lens array 152 of the pair of lens arrays 152 fastened with an adhesive 130 and the lower surface 152b of the second lens array 152. In other words, the light-shielding film 162 may be excluded from the opposing surfaces of the pair of lens arrays 152 (the lower surface 152b of the first lens array 152 and the upper surface 152a of the second lens array 152) fastened with the adhesive 130.
As illustrated in
The through-holes 170 are staggered to form two rows in the apparatus depth direction. More specifically, the through-holes 170 are arranged in the apparatus depth direction at equivalent, the same, or regular intervals. The through-holes 170 are arranged in the apparatus depth direction in two rows. A first one of the rows of the through-holes 170 and a second one of the rows of the through-holes 170 are shifted in the apparatus depth direction. In other words, the through-holes 170 each extending in the apparatus height direction are arranged in the apparatus depth direction in two rows adjacent in the apparatus width direction.
Thus, the multiple through-holes 170 viewed from above overlap the multiple microlenses 164 (refer to
The light-shielding member 150 is formed by fastening (bonding) six light-shielding portions 160 extending in the apparatus depth direction together with a bond such as an adhesive while being arranged in the apparatus depth direction.
The light-shielding portions 160 are formed integrally (with, for example, injection molding) with a black resin material (for example, acrylonitrile-butadiene-styrene copolymer resin or ABS resin). In the present exemplary embodiment, for example, the light-shielding portions 160 in
As illustrated in
Each light-shielding portion 160 includes base portions 160a extending in the apparatus depth direction, and extension portions 160b disposed at a center and both end portions of the light-shielding portion 160 in the apparatus depth direction. Each extension portion 160b extends to both sides in the apparatus width direction with respect to the base portion 160a.
In this structure, the reflected light reflected off the document G and passing through the slit 222 passes through the through-holes 170 in the light-shielding member 150, and, as illustrated in
In the reflected light passing through the through-holes 170, light inclined with respect to the apparatus height direction (axial directions of the through-holes 170) may be once reflected off the inner surfaces of the through-holes 170 of the light-shielding portions 160, and incident on the microlenses 164. However, light that enters the through-holes 170 at a large inclination angle is reflected multiple times off the inner surfaces of the through-holes 170, and has its amount repeatedly attenuated. Thus, the amount of light is at a negligible level regardless of when incident on the microlenses 164. Thus, the light-shielding member 150 disposed on the pair of lens arrays 152 reduces incidence of a large amount of stray light on the microlenses 164. At this time, stray light occurs at a portion out of an originally intended optical path, and is not used.
Light incident on the microlenses 164 of the first lens array 152 emerges from the microlenses 164 of the first lens array 152, and is incident on the microlenses 164 of the second lens array 152. Light incident on the microlenses 164 of the second lens array 152 emerges from the microlenses 164 of the second lens array 152 and converges to a light receiving element 126.
When the positions where the vertices of the ridges 156 of the first lens array 152 and the vertices of the ridges 154 of the second lens array 152 abut against each other are referred to as abutment positions,
As illustrated in
When viewed from above, the light receiving substrate 102 has a rectangular shape extending in the apparatus depth direction. On the upper surface of the light receiving substrate 102, the multiple light receiving elements 126 are arranged in a line in the apparatus depth direction. The light receiving elements 126 mounted on the light receiving substrate 102 face the condenser 112 in the height direction (refer to
As illustrated in
As illustrated in
As illustrated in
As illustrated in
Subsequently, the housing 114 is described in detail. As described above, the housing 114 includes the upper housing 200 and the lower housing 240.
The upper housing 200 is formed from resin, such as black modified-polyphenylenether resin (m-PPE) by molding (such as injection molding). As illustrated in
The body 202 of the upper housing 200 has the pair of light-guide containers 204 that respectively accommodate the paired light guides 110, the through-hole 210 that extends through in the propagation direction of reflected light reflected off the document G (referred to as “a light propagation direction” below), and containers 230 (refer to
As illustrated in
The pair of wall plates 208 are spaced apart in the apparatus width direction. The area (space) held between the pair of wall plates 208 serves as the hole upstream portion 210a of the through-hole 210 located upstream in the light propagation direction. The upstream end of the hole upstream portion 210a in the light propagation direction has the smallest width among other portions, and the upstream end of the through-hole 210 in the light propagation direction serves as the slit 222 that restricts part of reflected light reflected off the document G. The slit 222 is an example of an opening.
On the inner circumferential surfaces defining the through-hole 210 of the upper housing 200, at least portions irradiated with reflected light reflected off the document G are embossed. The portions irradiated with reflected light refer to the surfaces of the upper housing 200 defining the hole upstream portion 210a (the surfaces of the pair of wall plates 208 facing inward in the apparatus width direction). Embossing refers to a design with recesses and projections formed on the surface with a depth of greater than or equal to 2 μm.
The upper housing 200 has upward surfaces 280 facing upstream in the light propagation direction at the peripheral portion of the slit 222. The upward surfaces 280 are embossed.
The area surrounded by the body 202 and located below the support plates 206 is defined as a hole downstream portion 210b, or a downstream portion of the through-hole 210 in the light propagation direction.
The lower housing 240 is formed from resin, such as modified-polyphenyleneether resin (m-PPE) by molding (such as injection molding). As illustrated in
The body 242 has a rectangular cross section extending in the height direction. The through-hole 244 extends through the body 242 and the base end portion 260 in the light propagation direction, and the condenser 112 is disposed at the upper end portion of the through-hole 244. More specifically, in the condenser 112, the lower end portion of the first lens array 152 and the entirety of the second lens array 152 are located at the upper end portion of the through-hole 244, and held by opposing surfaces 244b defining the through-hole 244 and opposing in the apparatus width direction. In other words, the pair of lens arrays 152 are held by the opposing surfaces 244b defining the through-hole 244 formed in the body 242. The through-hole 244 formed in the resin-made body 242 is long and extends in the apparatus depth direction. Thus, the through-hole 244 is warped by, for example, mold shrinkage to have its width at the center portion in the apparatus depth direction reduced further than its width at the end portions (both end portions) in the apparatus depth direction. When the pair of lens arrays 152 are inserted into this through-hole 244, the pair of lens arrays 152 are held by the opposing surfaces 244b defining the through-hole 244. The pair of lens arrays 152 inserted into the through-hole 244 then correct the opposing surfaces 244b to reduce the warpage, and thus, also correct outer peripheral surfaces 246 of the body 242 to reduce the warpage.
The through-hole 244 has a step portion 244a that receives the end portions (ridges 156) of the second lens array 152.
The base end portion 260 has a rectangular cross section extending in the apparatus width direction, and the base end portion 260 has the container 262 that accommodates the light receiving substrate 102. The container 262 has the spot-facing surface 262a with which the upper surface of the light receiving substrate 102 comes into contact. The light receiving substrate 102 is fastened to the lower housing 240 with an adhesive (not illustrated) applied across the light receiving substrate 102 and the spot-facing surface 262a.
Subsequently, positioning of the upper housing 200 and the lower housing 240 in the apparatus depth direction is described.
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
Subsequently, positioning of the upper housing 200 and the lower housing 240 in the apparatus width direction and the height direction is described with reference to
As illustrated in
As illustrated in
As illustrated in
The lower portion of each protrusion 216 is tapered, and has a downward surface 216a facing downward. In other words, the lower portion of each protrusion 216 has a downward surface 216a facing downstream in the light propagation direction. The upper portion of each protrusion 216 has an inward surface 216b facing inward in the apparatus width direction. The downward surface 216a is an example of a second surface.
As described above, the upper housing 200 having the slit 222 is formed from a resin material by, for example, injection molding. Thus, the upper housing 200 alone is warped due to, for example, mold shrinkage, and the width of the slit 222 (refer to
As illustrated in
The upward surface 248a of each protrusion 248 of the lower housing 240 and the downward surface 216a of the corresponding protrusion 216 of the upper housing 200 are in contact with each other in the height direction. Thus, the upper housing 200 and the lower housing 240 are fixed in position in the height direction.
Subsequently, bonding of the upper housing 200 and the lower housing 240 is described with reference to, for example,
As illustrated in
As illustrated in
As illustrated in
When the upper housing 200 and the lower housing 240 are combined, as illustrated in
Subsequently, bonding of the first lens array 152 and the second lens array 152, bonding of the pair of lens arrays 152 and the light-shielding member 150, and shielding of the condenser 112 and the lower housing 240, and other operations are described.
As illustrated in
More specifically, as illustrated in
As illustrated in
As illustrated in
As illustrated in
Subsequently, a process of assembling the image reading device 100 is described with reference to the flowchart illustrated in
First, in step S100, as illustrated in
As described above, the lower housing 240 is formed by, for example, injection molding from a resin material. Thus, in the lower housing 240 alone, the width of the through-hole 244 at the center portion in the apparatus depth direction is narrower than the width of the through-hole 244 at end portions (both end portions) in the apparatus depth direction due to, for example, mold shrinkage. In other words, the pair of opposing surfaces 244b defining the through-hole 244 are warped into an arch. The pair of opposing surfaces 244b warped into an arch cause the pair of outer peripheral surfaces 246 of the body 242 to be warped to follow the contour of the opposing surfaces 244b. The condenser 112 is attached to the lower housing 240 while having the through-hole 244 widened with a jig not illustrated. More specifically, the lower portion of the condenser 112 is inserted into the through-hole 244 while the center portion of the through-hole 244 is widened with a jig not illustrated, and the lower housing 240 has its width restored from the widened state. Then, the condenser 112 is held in between the pair of opposing surfaces 244b defining the through-hole 244 of the lower housing 240. Thus, the pair of opposing surfaces 244b are corrected to reduce the warpage. The correction of the warped opposing surfaces 244b corrects the outer peripheral surfaces 246 to reduce the warpage. Thereafter, the sealant 134 is applied across the upper surface of the body 242 of the lower housing 240 and the side surface of the condenser 112, and solidifies to form a sealing portion.
Subsequently, as illustrated in
Subsequently, as illustrated in
As described above, the upper housing 200 is formed from a resin material by, for example, injection molding. Thus, in the upper housing 200 alone, the width of the slit 222 at the center portion in the apparatus depth direction is narrower than the width of the slit 222 at end portions (both end portions) in the apparatus depth direction due to, for example, mold shrinkage. Thus, the upper housing 200 is attached to the lower housing 240 while having the slit 222 widened with a jig not illustrated. More specifically, the body 242 of the lower housing 240 is inserted into the through-hole 210 while the center portion of the through-hole 210 is widened with a jig not illustrated, and the through-hole 210 has its width restored from the widened state.
In the state where the upper housing 200 is attached to the lower housing 240 (when the body 242 of the lower housing 240 is inserted into the through-hole 210 while the center portion of the through-hole 210 is widened), as illustrated in
When the body 242 of the lower housing 240 is kept being inserted into the through-hole 210 while the center portion of the through-hole 210 is widened, as illustrated in
Thereafter, when the center portion of the through-hole 210 is restored from the widened state, the outward surface 248b of each protrusion 248 on the lower housing 240 and the inward surface 216b of the corresponding protrusion 216 on the upper housing 200 come into contact with each other in the apparatus width direction. Thus, the upper housing 200 and the lower housing 240 are fixed in position in the apparatus width direction, and the width of the slit 222 is corrected. Specifically, the width of the slit 222 is restored to be uniform throughout in the apparatus depth direction.
After the upper housing 200 and the lower housing 240 are fixed in position in three directions (the apparatus depth direction, the height direction, and the apparatus width direction), as illustrated in
Subsequently, as illustrated in
Subsequently, the operations of the image reading device 100 are described.
The light emitting elements 128 illustrated in
Then, as illustrated in
Light incident on the microlenses 164 of the first lens array 152 emerges from the microlenses 164 of the first lens array 152, and is incident on the microlenses 164 of the second lens array 152. Light incident on the microlenses 164 of the second lens array 152 emerges from the microlenses 164 of the second lens array 152, and converges on the light receiving elements 126. Furthermore, the light receiving elements 126 receive the reflected light reflected off the document G and converts the light into electric signals.
As described above, in the image reading device 100, the outward surface 248b of each protrusion 248 on the lower housing 240 comes into contact with the inward surface 216b of the corresponding protrusion 216 on the upper housing 200 in the apparatus width direction to correct the width of the slit 222. Thus, compared to the case where the upper housing 200 and the lower housing 240 come into contact with each other simply in the propagation direction of reflected light, the image reading device 100 reduces narrowing the width of the slit 222 at the center portion in the apparatus depth direction with respect to the width of the slit 222 at end portions in the apparatus depth direction.
In the image reading device 100, the upper housing 200 is black. In other words, of the inner circumferential surfaces of the through-hole 210 of the upper housing 200, at least the surfaces that define the hole upstream portion 210a or the portions that are irradiated with reflected light (the surfaces of the pair of wall plates 208 facing inward in the apparatus width direction) are black. Thus, compared to the case where the entirety of the upper housing is milky white, in the image reading device 100 with this structure, reflected light that has passed through the slit 222 and that is reflected off the surfaces of the pair of wall plates 208 defining the through-hole 210 facing inward in the apparatus width direction is less likely to serve as stray light that is transmitted through the pair of lens arrays 152.
In the upper housing 200 of the image reading device 100, at least the surfaces defining the hole upstream portion 210a that are irradiated with reflected light (the surfaces of the pair of wall plates 208 facing inward in the apparatus width direction) are embossed. Thus, compared to the case where the portions in the upper housing irradiated with reflected light are smooth surfaces, in the image reading device 100 with this structure, reflected light that has passed through the slit 222 and that is reflected off the surfaces of the pair of wall plates 208 defining the through-hole 210 facing inward in the apparatus width direction is less likely to serve as stray light that is transmitted through the pair of lens arrays 152.
In the image reading device 100, the upward surfaces 280 facing upstream in the light propagation direction are formed at the peripheral portion of the slit 222 formed in the upper housing 200. The upward surfaces 280 are black or embossed. Thus, compared to the case where the upward surface is milky white and smooth, the image reading device 100 with this structure reduces stray light caused when part of reflected light that is reflected off the document G (that undergoes first reflection) is reflected again off the upward surfaces 280 (that undergoes second reflection), and the reflected light that has undergone the second reflection is applied to the document G to serve as reflected light reflected off the document G (reflected light that undergoes third reflection). In other words, compared to the case where the upward surface is milky white and smooth, in the image reading device 100 with this structure, part of reflected light (reflected light resulting from third reflection) resulting from reflection (second reflection) off the upward surfaces 280 is less likely to serve as stray light that is transmitted through the pair of lens arrays 152.
In the image reading device 100, the outward surface 248b of each protrusion 248 on the lower housing 240 and the inward surface 216b of the corresponding protrusion 216 on the upper housing 200 come into contact with each other in the apparatus width direction. Thus, the upper housing 200 and the lower housing 240 are fixed in position in the apparatus width direction to correct the width of the slit 222. Thus, compared to a structure where a flat surface portion of the lower housing 240 facing inward and a flat surface portion of the upper housing 200 facing outward are brought into contact with each other to correct the width of the slit 222, bringing components with high rigidity into contact with each other reduces the variation of the width of the slit 222 at the center portion in the apparatus depth direction.
In the image reading device 100, the upward surface 248a of each protrusion 248 on the lower housing 240 and the downward surface 216a of the corresponding protrusion 216 on the upper housing 200 come into contact with each other in the height direction. Thus, the upper housing 200 and the lower housing 240 are fixed in position in the height direction. Thus, compared with the case where they are fixed in position in the height direction (light propagation direction) by using a portion different from the protrusion to correct the width of the slit 222, the shape of the lower housing 240 is simplified.
In the image reading device 100, the adhesive 270 is filled in between each protrusion 256 on the lower housing 240 and the corresponding cover 220 on the upper housing 200 to bond the upper housing 200 and the lower housing 240 to each other. The image reading device 100 with this structure thus has higher bonding strength than a structure where the ridges are bonded by being abutted against each other.
In the image reading device 100, each projection 252 of the lower housing 240 is held in between the corresponding pair of holders 218 of the upper housing 200 in the apparatus depth direction. Thus, the upper housing 200 and the lower housing 240 are fixed in position in the apparatus depth direction. Compared to a structure where the lower housing 240 is abutted against the upper housing 200 on one side in the apparatus depth direction to be fixed in position in the apparatus depth direction, the image reading device 100 with this structure facilitates positioning in the apparatus depth direction.
In the image reading device 100, the multiple recesses 244c are formed on the opposing surfaces 244b that oppose in the apparatus width direction across the through-hole 244 to form gaps between the opposing surfaces 244b and the adhesive 130 that bonds the pair of lens arrays 152. The image reading device 100 with this structure thus reduces detachment of the adhesive 130 as a result of the lower housing 240 and the adhesive 130 rubbing against each other due to a difference between the degree (amount of dimensional change) of expansion and contraction of the lower housing 240 and the degree (amount of dimensional change) of expansion and contraction of the pair of lens arrays 152 caused by a change of the ambient environment (particularly, temperature and humidity).
In the image reading device 100, the sealant 134 serving as an elastic member is applied along the outer peripheries of the lens arrays 152 across the upper surface of the body 242 of the lower housing 240 and the side surface of the condenser 112. The image reading device 100 thus blocks stray light that is to pass between the lens arrays 152 and the body 242 while allowing the lens arrays 152 to expand and contract in the apparatus depth direction. More specifically, the light-shielding member 150 having the through-holes 170 corresponding to the microlenses 164 of the pair of lens arrays 152 is placed on the pair of lens arrays 152 at a portion upstream in the light propagation direction. The sealant 134 formed from an elastic member is applied along the outer periphery of the first lens array 152 across the body 242, the first lens array 152 located upstream in the light propagation direction, and the light-shielding member 150. In the image reading device 100 with this structure, reflected light that has passed through the slit 222 and that has been reflected off the inner circumferential surfaces of the through-hole 210 is less likely to serve as stray light that enters the pair of lens arrays 152 from the side surface (the surface facing outward in the apparatus width direction) of the first lens array 152 located upstream in the light propagation direction. In other words, the image reading device 100 with this structure reduces reflected light that has passed through the slit 222 and that has been reflected off the surfaces defining the hole upstream portion 210a of the through-hole 210 (the surfaces of the pair of wall plates 208 facing inward in the apparatus width direction) to serve as stray light that enters the pair of lens arrays 152 from the side surface (the surface facing outward in the apparatus width direction), exposed to the outside from the lower housing 240, in the first lens array 152 located upstream in the light propagation direction.
Compared to the structure including an image reading device for which an upper housing formed from a resin material is directly used, the image reading unit 60 including the image reading device 100 reduces degradation of the quality of read images.
Compared to the structure including an image reading unit including an image reading device for which an upper housing formed from a resin material is directly used, the image forming apparatus 10 including the image reading unit 60 reduces degradation of the quality of output images.
Although the present disclosure is described in detail with reference to a specific exemplary embodiment, the present disclosure is not limited to the exemplary embodiment. It is apparent to those skilled in the art that the present disclosure may be embodied in various other exemplary embodiments within the scope of the present disclosure.
For example, in the image reading device 100 according to the above exemplary embodiment, at least the surfaces (the surfaces of the pair of wall plates 208 facing inward in the apparatus width direction) of the upper housing 200 defining the hole upstream portion 210a and irradiated with reflected light are black and embossed. Instead, the surfaces may be either black or embossed, or neither black nor embossed. More specifically, although the upper housing 200 is black in the above exemplary embodiment, the upper housing 200 may be, for example, milky white. However, this structure has no effect resulting from the upper housing 200 being black.
Although at least the inner circumferential surfaces of the upper housing 200 defining the through-hole 210 and irradiated with the reflected light reflected off the document G are embossed in the above exemplary embodiment, the surfaces may be smooth. However, this structure has no effect resulting from the surfaces being embossed.
In the above exemplary embodiment, the upward surfaces 280 facing upstream in the light propagation direction are formed at the peripheral portions of the slit 222 of the upper housing 200, and the upward surfaces 280 are embossed. Specifically, the image reading device 100 in which the upward surfaces 280 are black and embossed is described. Instead, the upward surfaces 280 may be either black or embossed, or neither black nor embossed. However, the structure where the upward surfaces 280 are, for example, milky white has no effect resulting from the upward surfaces 280 being black. In addition, the structure where the upward surfaces 280 are, for example, smooth has no effect resulting from the upward surfaces 280 being embossed.
In the above exemplary embodiment, the outward surface 248b of each protrusion 248 on the lower housing 240 and the inward surface 216b of the corresponding protrusion 216 on the upper housing 200 come into contact with each other in the apparatus width direction to correct the width of the slit 222. Instead, flat surfaces may be brought into contact with each other to correct the width of the slit 222. However, this structure has no effect resulting from the protrusion 248 and the protrusion 216 being brought into contact with each other to correct the width of the slit 222.
In the above exemplary embodiment, each projection 252 on the lower housing 240 is held in between the pair of holders 218 of the upper housing 200 in the apparatus depth direction to fix the positions of the upper housing 200 and the lower housing 240 in the apparatus depth direction. Instead, the lower housing may be abutted against the upper housing on one side in the apparatus depth direction to fix the positions in the apparatus depth direction. However, this structure has no effect resulting from the projection 252 being held in between the pair of holders 218 to be fixed in position.
In the above exemplary embodiment, the image reading device 100 is described as an example of an optical device. Instead, another optical device other than an image reading device may be used.
The foregoing description of the exemplary embodiments of the present disclosure has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the disclosure and its practical applications, thereby enabling others skilled in the art to understand the disclosure for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the disclosure be defined by the following claims and their equivalents.
(((1)))
An optical device, comprising:
The optical device according to (((1))),
The optical device according to (((1))) or (((2))),
The optical device according to any one of (((1))) to (((3))),
The optical device according to (((4))),
The optical device according to any one of (((1))) to (((5))),
The optical device according to any one of (((1))) to (((6))),
The optical device according to any one of (((1))) to (((7))),
The optical device according to (((8))),
An image reading unit, comprising:
An image forming apparatus, comprising:
Number | Date | Country | Kind |
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2023-023608 | Feb 2023 | JP | national |