This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2023-123033 filed Jul. 28, 2023.
The present invention relates to an optical device and a document reading apparatus.
In JP2015-019213A, there is described a document reading apparatus in which a reading guide member in which a background reflection member is disposed is attached such that a rear end portion of a document on a downstream side in a transport direction can enter a state in which the rear end portion is lifted and tilted to a certain angle when the document being transported comes into contact, a light guide body has an emission surface that guides and emits light from a light source in a direction in which the background reflection member is irradiated with the light, and a width of the emission surface in a sub-scanning direction is set to a dimension with which the light is also emitted to the background reflection member when the reading guide member enters a state of being tilted such that the light is reflected by the background reflection member and received by a light receiving unit.
In JP2015-012347A, there is described a document reading apparatus including a background reflecting unit that is disposed in a state in which light from a light source is reflected to pass through a reading position and received by a light receiving unit, and reflects, in a state in which a document does not exist, the amount of reflection light larger than the amount of document reflection light reflected by the document, in which the background reflecting unit is configured by processing a mirror surface to reflect the amount of reflection light smaller than the amount of mirror surface reflection light reflected by the mirror surface.
In JP2015-023428A, there is described a document reading apparatus including a light source that irradiates a document passing through a reading position with light, a background portion that pinches the document passing through the reading position and is opposite to the light source, a first detection unit that is on an upstream side than the reading position in a transport direction of the document and detects a tip of the document, a second detection unit that detects an end portion of the document based on a difference between the amount of light reflected by the background portion and the amount of light reflected by the document from the light source, and a processing unit that performs a tip process based on a result of the first detection unit and performs a tilting process based on a result of the second detection unit.
In a case where the light guide body scatters the light incident from an end surface with a scatterer disposed in a direction in which a side surface extends, the amount of light received by the light receiving unit is reduced, and in a case where the amount of light is increased, the uneven amounts of light received by the light receiving unit occur.
Aspects of non-limiting embodiments of the present disclosure relate to an optical device and a document reading apparatus that reduce, in a case where a light guide body scatters light incident from an end surface with a scatterer disposed in a direction in which a side surface extends and emits the light, both a decrease in the amount of light received by a light receiving unit and occurrence of the uneven amounts of light received by the light receiving unit.
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.
According to an aspect of the present disclosure, there is provided an optical device including: a light guide body that scatters light incident from an end surface with a scatterer disposed in a direction in which a side surface extends and emits the light; a mirror surface reflecting plate that mirror-reflects the light emitted from the light guide body; a light receiving unit that receives the light reflected by the mirror surface reflecting plate; and a diffusion plate that diffuses and transmits the light emitted from the light guide body and emits the light onto the mirror surface reflecting plate, and diffuses and transmits the light reflected by the mirror surface reflecting plate and emits the light to the light receiving unit.
Exemplary embodiment(s) of the present invention will be described in detail based on the following figures, wherein:
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
As illustrated in
Above the first transparent plate 62 and the second transparent plate 72, an opening and closing cover 66 which opens or closes the first transparent plate 62 and the second transparent plate 72 is disposed. Inside the opening and closing cover 66, a transport unit 64 (so-called an ADF) which transports a plurality of documents G along a transport path 70 in the opening and closing cover 66 and passes the plurality of documents G through a document reading position R above the second transparent plate 72 is provided. Further, the transport unit 64 includes a reading guide member 210 that guides the document G being transported along the transport path 70 to the document reading position R and guides the document G in a discharge direction after passing through the document reading position R. Further, the reading guide member 210 is provided with a mirror surface reflecting plate 220 at a part of a lower surface portion facing the document reading position R.
In addition, in a space inside the housing 60A, an image reading unit 100 which reads an image of the document G placed on the first transparent plate 62 and the image of the document G transported to the document reading position R by the transport unit 64 is provided. Further, the image reading apparatus 60 includes a drive unit 74 which drives the image reading unit 100 in the apparatus width direction.
The drive unit 74 includes a shaft 76 extending in the apparatus width direction (a moving direction of the image reading unit 100) and a sliding member 78 which is attached to a lower surface of a housing 114 of the image reading unit 100 and which is slidably supported by the shaft 76.
Further, the drive unit 74 includes a motor (not illustrated), a drive pulley 84 which is rotationally driven by transmission of a drive force from the motor, a driven pulley 86 which is driven and rotated, and an endless belt 82 in an endless shape winding around the drive pulley 84 and the driven pulley 86. The drive pulley 84 is attached to one end of the shaft 76, and the driven pulley 86 is attached to the other end of the shaft 76.
Details of the image reading unit 100 will be described below.
In the image reading apparatus 60, the image reading unit 100 reads the image of the document G as follows. Specifically, in a case of reading the image of the document G transported by the transport unit 64, a drive force of the motor (not illustrated) is transmitted via the endless belt 82, so that the image reading unit 100 moves to a transport reading position on the other side in the apparatus width direction and stops, as illustrated in
Further, in a case of reading the image of the document G placed on the first transparent plate 62, although not illustrated, the image reading unit 100 moves from a reading start position toward a reading end position in the apparatus width direction along the first transparent plate 62 by the drive unit 74, while reading the image of the document G.
Here, the image reading apparatus 60 is an example of a document reading apparatus.
In these drawings, an up-down direction is indicated by H, an apparatus width direction is indicated by W, and an apparatus depth direction is indicated by D, respectively.
As illustrated in
Further, in a case where the image reading unit 100 reads the image of the document G transported by the transport unit 64, the image reading unit 100 is disposed in a downward direction of the second transparent plate 72 and is directly below the mirror surface reflecting plate 220, as illustrated in
Here, the second transparent plate 72 is an example of a reading window portion through which a document passes. Further, the mirror surface reflecting plate 220 is an example of a mirror surface reflecting plate that mirror-reflects light emitted from a light guide body.
The light receiving unit 125 has a light receiving substrate 102 and a plurality of light receiving elements 126 arranged in the apparatus depth direction. As illustrated in
In a case where the document G passes through the document reading position R on the second transparent plate 72, the light receiving unit 125 receives light emitted from the side surface 110B of the light guide body 110, which will be described below, and reflected by the document G. On the other hand, in a case where the document G does not pass through the document reading position R on the second transparent plate 72, the light receiving unit 125 receives light emitted from the side surface 110B of the light guide body 110, which will be described below, and reflected by the mirror surface reflecting plate 220.
Here, the light receiving unit 125 is an example of a light receiving unit that receives light reflected by a mirror surface reflecting plate. In addition, the light receiving unit 125 is an example of a light receiving unit that receives light emitted from a light guide body and reflected by a document in a case where the document passes through a reading window portion, and receives light reflected by a mirror surface reflecting plate in a case where the document does not pass through the reading window portion.
The rod lens array 112 is made of a transparent material (for example, glass), is formed in a rectangular parallelepiped shape extending in the apparatus depth direction, and is accommodated in a lens accommodating portion 114B in the housing 114, as illustrated in
Here, the rod lens array 112 is an example of a lens unit that guides light reflected by a mirror surface reflecting plate to a light receiving unit.
As illustrated in
As illustrated in
As illustrated in
Further, as illustrated in
Here, the diffusion pattern 111 is an example of a scatterer disposed in a direction in which a side surface extends. Further, the light guide body 110 is an example of a light guide body that emits light incident from an end surface after being scattered by the scatterer.
As illustrated in
The wiring substrate 104 is a so-called flexible flat cable, and is provided in pairs, as illustrated in
The element substrate 106 is a so-called flexible printed circuit substrate, and a plate thickness direction of the element substrate 106 is the apparatus depth direction. The element substrate 106 is a substrate having a rectangular shape as viewed from the apparatus depth direction, is accommodated in a substrate accommodating portion 114C of the housing 114, and is provided in pairs, as illustrated in
As illustrated in
Meanwhile, in such an image reading apparatus 60, in a case where the transport unit 64 transports the document G along the transport path 70, the document G is tilted in some cases. In preparation for such a case, the image reading apparatus 60 may have a function of mechanically correcting the inclination of the document G (hereinafter, “mechanical skew correction function”). With the mechanical skew correction function, an inclination of a tip of the document G is corrected by abutting the document G against a stopped roller to create a loop, and a variation in a timing at which each location of the tip of the document G arrives at the document reading position R is reduced. Meanwhile, this mechanical skew correction function has a problem in that an impact sound in a case where the tip of the document G collides with the roller, an impact sound in a case where the loop of the document G is created or eliminated, and the like are generated.
In order to address such a problem, the image reading apparatus 60 may have a function of detecting a tilt angle of the document G and correcting the tilt angle by image processing. Meanwhile, the tilt angle of the document G cannot detected in a case where a difference between an output value of light reflected by the document G in a case where the document G passes through the document reading position R, and an output value of light reflected by the mirror surface reflecting plate 220 in a case where the document G does not pass through the document reading position R is equal to or more than a predetermined reference. Specifically, for example, in a case of 8-bit 256 gradations output, an output value of light reflected by the document G of a color of white is a value close to 240 LSB, so that an output value of light reflected by the mirror surface reflecting plate 220 is to be higher than 240 LSB.
Meanwhile, in a case where the light emitting element 128 adopts an illumination system that emits light from the end surface 110A of the light guide body 110 as in the image reading apparatus 60 described above, an output of the light from the light guide body 110 is reduced, so that an output of light reflected by the mirror surface reflecting plate 220 is also reduced. Further, in order to increase a speed of image reading or increase a focal depth, it is required to increase the output of the reflected light. Meanwhile, the image reading apparatus 60 described above cannot meet such a requirement.
Although a last output is illustrated in a form of 256 gradations output in the previous example, in a stage before the last output, a process is performed with a larger number of gradations, for example, 10-bit 1024 gradations, and the last output is rounded with 8-bit 256 gradations, in some cases. In the following, for the sake of description, a 10-bit output will be used.
That is, there is no mirror surface reflecting plate 220 of the existing technique that does not cause a shortage of output of the reflected light and does not cause occurrence of the unevenness.
In addition, in recent years, the image reading apparatus 60 may have a function of detecting and correcting dust on the second transparent plate 72 (hereinafter, referred to as a “dust detection and correction function”).
On the other hand, in a case where a lower limit of a region (regions M1 and M2 in
In a case where the mirror surface reflecting plate 220 and the diffusion plate 230 are combined in this manner, light emitted from the light guide body 110 passes through the diffusion plate 230, and the light reflected by the mirror surface reflecting plate 220 passes through the diffusion plate 230 again. That is, the light passes through the diffusion plate 230 twice. Thus, it is possible to increase the output of the light reflected by the mirror surface reflecting plate 220, and reduce the unevenness due to the reflected light.
Here, the diffusion plate 230 is an example of a diffusion plate that diffuses and transmits light emitted from a light guide body and emits the light on a mirror surface reflecting plate, and diffuses and transmits the light reflected by the mirror surface reflecting plate and emits the light to a light receiving unit. Further, a portion including the light guide body 110, the mirror surface reflecting plate 220, the diffusion plate 230, and the light receiving unit 125 is an example of an optical device.
Meanwhile, in
Further, in
Therefore, in the present exemplary embodiment, among the surfaces of the diffusion plate 230, a surface with low reflection, that is, a surface with low specular reflectance is disposed on the image reading unit 100 side. Specifically, the light diffusion layer 234 is disposed on the image reading unit 100 side of the base material 232, and the backing coat layer 236 is disposed on the mirror surface reflecting plate 220 side of the base material 232.
In the above description, a surface of the backing coat layer 236 is used as a surface with high reflection, a surface of the light diffusion layer 234 is used as a surface with low reflection, and the light diffusion layer 234 is disposed to face the light receiving unit 125 side. Meanwhile, the surface to be used is not limited to this. More generalized, a surface of a first layer having a first specular reflectance may be used as a surface with high reflection and a surface of a second layer having a second specular reflectance lower than the first specular reflectance may be used as a surface with low reflection, and the second layer may be disposed to face the light receiving unit side. In this case, the backing coat layer 236 is an example of the first layer, and the light diffusion layer 234 is an example of the second layer.
In a modification example of the mirror surface reflecting plate 220 according to the present exemplary embodiment, recess portions are provided along a longitudinal direction of the light guide body 110 on the image reading unit 100 side of the mirror surface reflecting plate 220. That is, in the modification example of the mirror surface reflecting plate 220, the recess portions blur an apparent distance away, thereby eliminating the occurrence of unevenness.
In addition, in
In the above description, the recess portions are provided along the longitudinal direction of the light guide body 110 on the image reading unit 100 side of the mirror surface reflecting plate 220, and the description is not limited to this. The mirror surface reflecting plate 220 may have a property of preventing the light receiving unit 125 from being located within a focal depth of the rod lens array 112. In the above description, as an example of a method in which the mirror surface reflecting plate 220 has such a property, a method of disposing a recessed shape in a direction in which a side surface of the light guide body 110 extends is used.
In the modification example of the mirror surface reflecting plate 220, for example, the sheet-shaped diffusion plate 230 may be attached along the recess portions of the mirror surface reflecting plate 220.
Further, even in a case where the mirror surface reflecting plate 220 is not provided with the recess portion, for example, the reading guide member 210 to which the mirror surface reflecting plate 220 is attached may be provided with a recess portion, and the sheet-shaped mirror surface reflecting plate 220 and diffusion plate 230 may be attached along the recess portions of the reading guide member 210.
(((1)))
An optical device comprising:
The optical device according to (((1))),
The optical device according to (((2))),
The optical device according to (((1))), further comprising:
The optical device according to ((4))),
A document reading apparatus comprising:
The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention 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 invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
Number | Date | Country | Kind |
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2023-123033 | Jul 2023 | JP | national |