JP7501099B2 - Reading device, output device and image forming device - Google Patents

Description

The present invention relates to a reading device, an output device, and an image forming device.

Patent document 1 describes a reading device in which the angle of incidence of light irradiated by a second irradiating means, which irradiates light to read a portion of the specularly reflected light component from the document, on the document has a non-zero angle with respect to the reflection angle of the principal ray of the specularly reflected light guided to the light guiding means.

JP 2010-130444 A

In a reading device that reads an image displayed in a reflective area that reflects the reflected light that reaches an image sensor, the wider the reflective area, the greater the advantage of the increased amount of reflected light. However, when attempting to read specularly reflected light, the light reflected by the reflective area is likely to include diffusely reflected light other than specularly reflected light, which may affect image quality.
Therefore, an object of the present invention is to reduce the amount of diffusely reflected light reflected in the reflection area while maintaining the uniformity of light, as compared to a case in which the reflection area of the document is narrowed by narrowing the exit surface.

The reading device according to claim 1 of the present invention is characterized by comprising an emission section having an emission surface that emits light and has a longitudinal direction in the main scanning direction, a reflection section that reflects the light emitted from the emission surface and has a reflection surface that has a longitudinal direction in the main scanning direction, the short dimension of the reflection surface being shorter than the short dimension of the emission surface, and an image sensor that generates an image represented by the light reflected by the reflection section and specularly reflected from the document.

The reading device according to claim 2 of the present invention is the embodiment described in claim 1, characterized in that the reflecting surface is arranged in the direction in which the amount of light emitted by the emission section is greatest.

The reading device according to claim 3 of the present invention is the embodiment described in claim 1 or 2, characterized in that the exit surface is rectangular.

The reading device according to claim 4 of the present invention is an embodiment of any one of claims 1 to 3, characterized in that the emission section includes a light source that emits light, and a light guide having a flat emission surface and guiding the light from the light source to the emission surface, and the light guide has a portion whose cross section intersecting a plane perpendicular to the emission surface is rectangular.

The reading device according to claim 5 of the present invention is an embodiment according to any one of claims 1 to 4, characterized in that it includes a second emission section that emits light and has a second emission surface with the main scanning direction as its longitudinal direction, and is arranged so that an image represented by the light emitted by the second emission section and diffusely reflected by the document is generated by the image sensor.

The reading device according to claim 6 of the present invention is an embodiment of any one of claims 1 to 5, characterized in that the exit surface has a diffusion section that diffuses the emitted light.

The reading device according to claim 7 of the present invention is the embodiment described in claim 5, characterized in that the exit surface for diffuse reflection of the second exit section diffuses the emitted light to a greater extent than the exit surface for regular reflection of the exit section.

The output device according to claim 8 of the present invention is characterized in that it includes a reading device according to any one of claims 1 to 7, and outputs the degree of specular reflection based on the specular reflection light read by the reading device.

The image forming device according to claim 9 of the present invention is characterized in that it includes the output device according to claim 8 and outputs an image formed based on the degree of regular reflection read by the reading device.

According to the inventions of claims 1, 8 and 9, it is possible to reduce the amount of diffuse reflected light reflected in the reflection area while maintaining the uniformity of the light, compared to when an attempt is made to narrow the exit surface and thereby narrow the reflection area of the document.
According to the second aspect of the present invention, compared to a case in which the reflective surface is disposed in a different direction, it is possible to suppress the likelihood that areas with low light quantity will be included in the specularly reflected light.
According to the third and fourth aspects of the invention, the light quantity distribution can be stabilized even when there is a tolerance in the shape of the light guide, compared to when the shape is not rectangular.
According to the fifth aspect of the present invention, the reading device can be made smaller than when the optical paths of the diffusely reflected light and the specularly reflected light are different.
According to the sixth aspect of the present invention, the reflection area of the document can be narrowed while maintaining the uniformity of the light, compared to a case where no diffusion portion is provided.
According to the seventh aspect of the present invention, the influence of diffuse reflected light on the image quality can be reduced, compared to the case where the magnitude relationship of the degree of diffusion is the opposite of that of the present invention.

FIG. 1 is a diagram illustrating a hardware configuration of an image reading apparatus according to an embodiment. FIG. 2 is a diagram showing a detailed configuration of an image reading unit. Enlarged view of the carriage Diagram showing the emission surface as seen from the front FIG. 13 is a diagram illustrating an example of a light amount distribution of light emitted from a light emitting portion for regular reflection; A magnified view of the specular reflector and its surroundings Diagram showing a reflecting surface seen from the front FIG. 1 is a diagram illustrating an example of a light amount distribution of light reflected by a reflecting surface. FIG. 1 is a diagram for explaining a case where the original 2 is lifted; A close-up of two light sources A diagram showing an example of specular reflected light mixed with diffuse reflected light FIG. 13 is a diagram showing a modified specular reflector; FIG. 13 is an enlarged view of a carriage according to a modified example; FIG. 13 is an enlarged view of a carriage according to a modified example; FIG. 13 is an enlarged view of a carriage according to a modified example; FIG. 13 is a diagram illustrating an example of a light amount distribution of light emitted from a light emitting portion for regular reflection; FIG. 13 is a diagram illustrating a modified example of a light output section for regular reflection. FIG. 13 is a diagram illustrating a modified image forming apparatus.

[1] Example Fig. 1 shows a hardware configuration of an image reading device 10 according to an example. The image reading device 10 is a device that reads an image shown on a document. The image reading device 10 is an example of a "reading device" of the present invention. The image reading device 10 includes a processor 11, a memory 12, a storage 13, a communication unit 14, a UI unit 15 (UI = User Interface), and an image reading unit 20. Note that the image reading device 10 may be composed of only the image reading unit 20.

The processor 11 includes, for example, an arithmetic unit such as a CPU (Central Processing Unit), a register, and peripheral circuits. The memory 12 is a recording medium readable by the processor 11, and includes, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory). The storage 13 is a recording medium readable by the processor 11, and includes, for example, a hard disk drive or a flash memory.

The processor 11 controls the operation of each piece of hardware by executing programs stored in the ROM and storage 13 using the RAM as a work area. The communication unit 14 has an antenna, a communication circuit, etc., and communicates via a communication line (not shown). The program executed by the processor 11 may be obtained from an external device communicating via the communication unit 14.

The UI unit 15 is an interface provided to a user who uses the device. The interface is a device that accepts information input by the user and outputs the information by the image reading device 10. The UI unit 15 has, for example, a touch screen that has a display as a display means and a touch panel provided on the surface of the display, and displays images and accepts operations from the user.

The image reading unit 20 includes a light source, an optical system, an image sensor, etc., and reads the image shown on the document by reflecting light from the light source off the document. The image reading unit 20 supplies document image data indicating the image of the read document to the processor 11. The processor 11 uses the supplied document image data to perform various processes (printing process, facsimile transmission process, etc.).

Figure 2 shows the detailed configuration of the image reading unit 20. In Figure 2, the image reading unit 20 is shown as seen in a direction along the main scanning direction A1. Note that the main scanning direction A1 in the figure is represented by an arrow pointing from the front to the back of the page, but the direction from the back to the front of the page is also referred to as the main scanning direction A1.

The image reading unit 20 comprises a document table 21, a document cover 22, a carriage 30, a carriage 40, an imaging lens 50, and an image sensor 60. These components of the image reading unit 20 have a width in the main scanning direction A1. The carriage 30, the carriage 40, the imaging lens 50, and the image sensor 60 all have an elongated shape with the main scanning direction A1 as their longitudinal direction. The direction indicated by the arrow marked "A2" in the figure is the sub-scanning direction A2. The image reading unit 20 is a so-called reduced optical system reading device.

The manuscript table 21 is a transparent glass plate that supports the manuscript 2, which is the object of image reading. The manuscript table 21 may be an acrylic plate or the like as long as it is a transparent plate-like member. The manuscript cover 22 covers the manuscript table 21 to block external light, and sandwiches the manuscript 2 between the manuscript table 21 and the manuscript cover 22. The manuscript 2 is supported by the manuscript table 21 and the manuscript cover 22 so as not to move.

When reading the original 2, the carriage 30 moves in the sub-scanning direction A2 at a set speed. The carriage 30 has an irradiation section that irradiates the original 2 with light, which will be described in detail later with reference to FIG. 3. The carriage 30 has a mirror 35. In this embodiment, the carriage 30 is box-shaped with an open top, and the mirror 35 is disposed inside it. Note that the carriage 30 does not have to be box-shaped, and may be hollow as long as it can move together. The mirror 35 reflects the light reflected by the original 2. The reflected light is guided to the optical path B1 that leads to the image sensor 60.

When reading the original 2, the carriage 40 moves in the sub-scanning direction A2 at half the speed of the carriage 30. The carriage 40 has mirrors 41 and 42 inside. The mirrors 41 and 42 reflect the light reflected by the mirror 35 and guide it to the optical path B1. The imaging lens 50 forms an image of the light reflected by the mirror 42 at a determined position.

The image sensor 60 has a light receiving element such as a CCD (Charge Coupled Device), receives the light focused by the imaging lens 50, and generates an image signal according to the received light. The image sensor 60 supplies the generated image signal to the processor 11 shown in FIG. 1. The processor 11 generates image data of the original 2 based on the supplied image signal.

Figure 3 shows an enlarged view of the carriage 30. The carriage 30 has a light emitting section 31 for specular reflection, a light emitting section 32 for diffuse reflection, a reflector 33 for specular reflection, a reflector 34 for diffuse reflection, and a mirror 35.

The light emitting section 31 for specular reflection has an exit surface 313 and emits light from the exit surface 313. The light emitting section 32 for diffuse reflection has an exit surface 323 and emits light from the exit surface 323. The light emitting section 31 for specular reflection is an example of an "exit section" in the present invention, and the light emitting section 32 for diffuse reflection is an example of a "second exit section" in the present invention. The light emitting section 31 for specular reflection has a light source 311 and a light guide 312. The light source 311 is a light source that emits light, such as an LED (Light Emitting Diode).

The light guide 312 is a transparent member that transmits light to the inside. The light guide 312 has the aforementioned exit surface 313, and guides the light from the light source 311 to the exit surface 313. The exit surface 313 is generally flat, but has minute undulations, which diffuse the emitted light. The exit surface 313 is an example of the "diffusion section" of the present invention. The diffuse reflection light exit section 32 has a light source 321 and a light guide 322. The light source 321 is a light source that emits light, such as an LED.

The light guide 322 is a transparent member that transmits light to the inside. The light guide 322 has the aforementioned exit surface 323, and guides the light from the light source 321 to the exit surface 323. The exit surface 323 is generally flat, but has fine undulations, which diffuse the emitted light. The structure of the light output section 32 for diffuse reflection is the same as that of the light output section 31 for regular reflection. Compared to the exit surface 313 for regular reflection of the light output section 31 for regular reflection, the exit surface 323 for diffuse reflection of the light output section 32 for diffuse reflection diffuses the emitted light to a greater extent.

The shapes of the emission surface 313 and the emission surface 323 will be described with reference to FIG.
4 shows the exit surface 313 as viewed from the front. The exit surface 313 is a surface whose longitudinal direction is the main scanning direction A1, and has a rectangular shape as viewed from the front. The light guide 312, the light source 311, and the specular reflection light exit section 31 having these are also members whose longitudinal direction is the main scanning direction A1. The dimension of the exit surface 313 in the short side direction A3 is dimension W1.

The short direction A3 is a direction perpendicular to the longitudinal direction of the emission surface 313 (= the direction along the main scanning direction A1) and along the emission surface 313. The diffuse reflection light emission section 32 is a member of the same shape and size as the specular reflection light emission section 31. Therefore, the emission surface 323 is also a surface whose longitudinal direction is the main scanning direction A1, and has a rectangular shape when viewed from the front.

In addition, light guide 312 has a portion whose cross section intersecting with a plane perpendicular to exit surface 313 is rectangular, and light guide 322 has a portion whose cross section intersecting with a plane perpendicular to exit surface 323 is rectangular. When the front shapes of exit surface 313 and exit surface 323 and the cross-sectional shapes of light guide 312 and light guide 322 are rectangular in this way, the light quantity distribution is more likely to be stable even if a tolerance occurs in the shape of the light guide, compared to when they are not rectangular.

The light amount distribution here refers to a distribution expressed by the amount of light passing through each position on an imaginary plane parallel to the emission surface 313 when the imaginary plane is provided in the space irradiated with light.
Fig. 5 shows an example of the light amount distribution of the light emitted by the light emitting portion for specular reflection 31. In the example of Fig. 5, a distribution D1 of the light amount when a plane positioned at a distance L1 from the emission surface 313 of the light guide 312 is viewed in a direction along the main scanning direction A1 is shown in a graph.

As described above, the carriage 30 has an elongated shape with the main scanning direction A1 as its longitudinal direction. The light source 311, the light guide 312, and the specular reflection light emitting section 31 having them, and the light source 321, the light guide 322, and the diffuse reflection light emitting section 32 having them, all of which are members with the main scanning direction A1 as their longitudinal direction. In other words, the longitudinal direction of these members is along the main scanning direction A1.

The exit surface 313 is a surface whose longitudinal direction is the main scanning direction A1. The direction perpendicular to the main scanning direction A1 and the longitudinal direction and along the exit surface 313 is referred to as the short direction A3. The horizontal axis of the graph shown in FIG. 5 represents the spatial position in the short direction A3. The vertical axis of the graph shown in FIG. 5 represents the amount of light passing through each position. Here, the optical path of light that passes through the center of the exit surface 313 and is emitted in the normal direction of the exit surface 313 is referred to as the optical axis C1.

The light exit surface 313 diffuses light in both the main scanning direction A1 and the short side direction A3 due to the fine undulations described above. This prevents the amount of light from concentrating at a specific position, and ensures that the amount of light is uniform. However, this does not result in complete uniformity, so the amount of light at each spatial position in the short side direction A3 is maximum on the optical axis C1 and decreases with distance from the optical axis C1.

The light quantity distribution D1 extends over a range wider than the dimension W1 of the short side direction A3 of the exit surface 313. This is because the exit surface 313 is not a perfect plane but has some undulations, which causes the emitted light to be diffused, and because light has the tendency to travel in directions other than a straight line. The shape of the specular reflector 33 is designed as shown in Figure 3 so that only a portion of the light emitted from the exit surface 313 is reflected toward the original 2.

A part of the light emitted from the emission surface 313 reaches the specular reflector 33 as shown in FIG.
6 shows an enlarged view of the periphery of the specular reflector 33. The specular reflector 33 is a member having a reflecting surface 331 that reflects the light emitted from the emission surface 313 toward the original 2. The specular reflector 33 is an example of the "reflecting portion" of the present invention. In this embodiment, the reflecting surface 331 is a flat reflecting surface.

Figure 7 shows the reflecting surface 331 as viewed from the front. As shown in the figure, the reflecting surface 331 of the specular reflector 33 is a surface whose longitudinal direction is the main scanning direction A1, similar to the exit surface 313 of the light guide 312, and has a rectangular shape when viewed from the front. Furthermore, the dimension W2 in the short direction A4 of the reflecting surface 331 is shorter than the dimension W1 in the short direction A3 of the exit surface 313. Note that the dimension W2 is not only smaller than the dimension W1, but is also smaller than the short dimension of the reflecting surface 341 of the diffuse reflector 34.

Furthermore, dimension W2 is smaller than the short-side dimension of the exit surface 323 of the diffuse reflection light exit section 32. On the other hand, the short-side dimension of the reflecting surface 341 is larger than the short-side dimension of the exit surface 323. In this embodiment, dimension W1 and the short-side dimension of the exit surface 323 are the same. In this embodiment, dimension W1 is 4.5 mm, and dimension W2 is 2.0 mm. Therefore, reflecting surface 331 reflects only a portion of the light emitted from exit surface 313. As a result, the distribution of the light amount in the reflected light changes as follows.

Figure 8 shows an example of the light quantity distribution of the light reflected by the reflecting surface 331. Figure 8 shows the specular reflector 33 and the light quantity distribution D2 of the light reflected therefrom. Figure 8 also shows the optical axis C1 of the light reflected by the reflecting surface 331 of the specular reflector 33. Figure 8 also shows the light quantity distribution D1 shown in Figure 5 with a two-dot chain line.

Since light outside the specular reflector 33 is not reflected by the specular reflector 33, the amount of light outside the specular reflector 33 is reduced in light amount distribution D2 compared to distribution D1. However, the light reflected by the specular reflector 33 diverges slightly even after being reflected by the specular reflector 33 and the width of the light beam increases, so that the amount of light also appears outside the width of the specular reflector 33 before it reaches the original.

As shown in Figures 5 and 8, the amount of light emitted by the light emitting section 31 for specular reflection is greatest along the optical axis C1. The reflecting surface 331 of the reflector 33 for specular reflection reflects the light passing through the optical axis C1. In other words, the reflecting surface 331 is disposed in a direction in which the amount of light emitted by the light emitting section 31 for specular reflection is greatest. By setting the optical path to include the optical axis C1 while restricting the light in this way, stable light can be directed toward the original 2. Furthermore, the orientation of the self-reflecting surface of the reflecting surface 331 is fixed so that the light reflected by the self-reflecting surface reaches the reading area R1 of the original 2 shown in Figure 3.

When the light reflected by the reflective surface 331 reaches the reading area R1 of the original 2, the original 2 reflects the light. The light reflected by this original is hereinafter referred to as "original reflected light." This original reflected light includes both specular reflection and diffuse reflection, but in this embodiment, the light specularly reflected by the original 2 is directed toward the mirror 35. Note that specular reflection here is not limited to perfect specular reflection in which the angle of incidence and the angle of reflection are perfectly equal, but also includes cases where the angles are slightly off as long as approximately the same characteristics are obtained.

In this embodiment, the mirror 35 is disposed vertically below the reading area R1. By disposing the mirror 35 in this manner, it is possible to cope with the case where the original 2 is lifted off the platen 21.
9A and 9B are diagrams for explaining a case where the original 2 is lifted. Fig. 9A shows a case where the mirror 35 is not disposed vertically below the reading region R1, and Fig. 9B shows a case where the mirror 35 is disposed vertically below the reading region R1.

The specularly reflected light incident on mirror 35 in FIG. 9(a) has a smaller angle of incidence with respect to original 2 than the specularly reflected light incident on mirror 35 in FIG. 9(b), so if original 2 floats, the optical path of the specularly reflected light is significantly shifted and it is likely not to be incident on mirror 35. In other words, even if the positional relationship between mirror 35 and original 2 changes due to the original 2 floating, the reduction in specularly reflected light reflected by mirror 35 is suppressed in the case of FIG. 9(b) compared to the case of FIG. 9(a).

On the other hand, when trying to receive light that is completely specularly reflected vertically downward, the incident light must also be incident vertically downward. However, this is not possible due to the structure, so in this embodiment, the light is tilted at about 5 degrees. Although it is not completely specularly reflected light, the reflection characteristics are detected to be almost the same as specularly reflected light. Note that the angle is not limited to 5 degrees as in this embodiment, and if it is 9 degrees or less, an image similar to specularly reflected light is detected to some extent.

The light specularly reflected by the original 2 is reflected by the mirror 35 and guided to the optical path B1 shown in FIG. 2 that leads to the image sensor 60. In this way, for the light specularly reflected by the original 2, the specular reflector 33 forms an optical path that guides the light emitted from the exit surface 313 of the light guide 312 that is directed toward the reflecting surface 331 of the specular reflector 33 to the original 2, that is, an optical path for the light that is directed toward the specular reflector 33 and an optical path that is reflected by the specular reflector 33 and directed toward the original 2.

The light reflected by the specular reflector 33 and specularly reflected by the original 2 is guided by mirrors 35, 41, 42, and imaging lens 50 to reach the image sensor 60. The image sensor 60 generates an image represented by the light that has reached it, i.e., the light specularly reflected by the original 2. As described above, part of the light emitted by the specular light emitting section 31 is reflected by the specular reflector 33 and is further specularly reflected by the original 2 to represent an image.

On the other hand, the light emitted by the diffuse reflection light emitting section 32 is diffusely reflected by the original 2 to show the image. Most of the light emitted from the emission surface 323 of the light guide 322 of the diffuse reflection light emitting section 32 heads directly towards the reading area of the original 2, but a diffuse reflection reflector 34 is provided so that the light that is not headed directly can also be directed towards the original 2. Since it is desirable to receive as much diffuse reflection light as possible, the configuration is such that more light heads towards the original 2.

Therefore, the reflecting surface 341 of the diffuse reflector 34 has a width such that the light traveling from the exit surface 323 toward the diffuse reflector 34 travels toward the reading area of the original 2, and is fixed in a direction that reflects the light toward the reading area of the original 2. In other words, the specular reflector 33 is disposed in a position such that the specularly reflected light that is reflected by the reflecting surface 331 and reaches the original 2 does not travel toward the optical path B1.

Therefore, part of the light that is reflected by the reflecting surface 331 and reaches the original 2 is diffusely reflected and travels along optical path B1 as shown in FIG. 3. The light that travels along optical path B1 is guided to the image sensor 60 by mirrors 35 and the like. In this way, the diffuse reflection light emitting section 32 is positioned so that an image represented by the light emitted by its own emitting section and diffusely reflected by the original 2 is generated by the image sensor 60. As described above, the image sensor 60 generates an image from both the light that is diffusely reflected and the light that is specularly reflected in the reading region R1.

In addition, the light emitted from the exit surface 323 of the light guide 322 and directed directly toward the reading area of the original 2 is diffusely reflected by the original and directed toward optical path B1. In this way, the reading area of the original 2 diffusely reflects the light approaching from two directions, and the diffusely reflected light is directed to the image sensor 60 by optical path B1, which is the same optical path as the specularly reflected light described above. The image sensor 60 generates an image represented by the light that has reached it, i.e., the light that has been diffusely reflected by the original 2.

Next, the detailed configuration of the light source 311 and the light source 321 will be described.
10 shows an enlarged view of light source 311 and light source 321. Light source 311 has a substrate 111 that supports an electronic circuit, a light-emitting unit 112 that emits light, and a fastener 113 that fixes substrate 111. Light-emitting unit 112 is, for example, an LED array, and is provided close to a lower end 114 of substrate 111. Substrate 111 is fixed to a frame of its own device by fastener 113 provided on the side opposite end 114.

The light source 321 has a substrate 211 that supports an electronic circuit, a light-emitting unit 212 that emits light, and a fastener 213 that secures the substrate 211. The light-emitting unit 212 is, for example, an LED array, and is provided close to the lower end 214 of the substrate 211. The substrate 211 is secured to the frame of the device by the fastener 213 provided on the side opposite the end 214. The substrate 111 and the light-emitting unit 112 are provided in different orientations, but are manufactured as a common part to the substrate 211 and the light-emitting unit 212.

This reduces the number of production lines for the parts and reduces the cost of manufacturing the parts compared to when these are separate parts. Also, by providing each fastener on the opposite side of the light-emitting unit, the light-emitting unit 112 and the light-emitting unit 212 are positioned closer together compared to when the fasteners are positioned differently from this embodiment.

As shown in FIG. 10, the light sources 311 and 321 are provided so that the end 114 of the substrate 111 and the end 214 of the substrate 211 are adjacent to each other. This allows the light emitting units 112 and 212 to be positioned closer together, and shortens the wiring required to supply power to each light emitting unit, compared to when the end 114 of the substrate 111 and the end 214 of the substrate 211 are not adjacent to each other.

Reflectors and mirrors are arranged so that the reflected light from the original 2 is guided to the image sensor 60 via optical path B1, which is a common optical path for specular reflection and diffuse reflection, but the timing of the light irradiation is separate. First, the image reading unit 20 turns on the diffuse reflection light emitting unit 32, moves the carriage 30 and the carriage 40 to the end of the original in the sub-scanning direction, reads the original 2, and supplies the processor 11 with original image data showing an image of the diffuse reflection light from the original 2.

Next, when carriage 30 and carriage 40 are returned to their original positions from the ends in the sub-scanning direction, specular reflection light emitting section 31 is turned on, original document 2 is read, and original document image data showing an image of the specularly reflected light of original document 2 is supplied to processor 11. In this manner, in this embodiment, an image shown by specularly reflected light and an image shown by diffusely reflected light are read separately for one original document. Processor 11 performs processing to obtain one image using the supplied image data showing the two images.

In this embodiment, the reading region R1 is sandwiched between the diffuse reflection reflector 34 and the diffuse reflection light emitting section 32, but the diffuse reflection light emitting section 32 may be disposed on both sides of the reading region R1. In this embodiment, the shape of the light guide is the same for both specular reflection and diffuse reflection, but this may be different. Also, the shape of the cross section of the light guide perpendicular to the longitudinal direction is the same everywhere, but the shape may change in the longitudinal direction. Also, the emission surface may be multiple faces rather than a single flat surface.

In this embodiment, the light emitted by the specular reflection light emitting section 31 is specularly reflected by the original 2 as the light with a narrower light distribution range as shown in FIG. 6 by the specular reflection reflector 33 as described above, and is guided to the image sensor 60. If the range of the light distribution of the light incident on the area on the surface of the original 2 that reflects the specular reflection light is too wide, the specular reflection light from a certain area such as the optical axis C1 in this embodiment, or from other areas that are distant areas, deviates from the optical path B1, and conversely, the diffuse reflection light of that light heads toward the optical path B1.

Figure 11 shows an example in which specularly reflected light is mixed with diffusely reflected light. Figure 11 (a) shows, as a comparative example, a state in which the diffusely reflected light of light emitted by the specular light emitting portion 31 and reflected by the specular reflector 33x is directed toward the image sensor 60. The light that enters the original 2 through the optical path E11 with a deep incident angle (the closer the angle to the original 2 is to 90 degrees, the deeper the incident angle is) has an angular relationship with the light that travels through the optical path E12 toward the image sensor 60 that is almost specularly reflected, but the light that enters the original 2 through the optical path E21 with a shallow incident angle does not travel toward the image sensor 60 through the optical path E22.

Instead, the diffuse reflection of light that entered the original 2 through optical path E21 travels toward the image sensor 60 through optical path E23. In such a case, the image sensor 60 receives both the specular reflection and the diffuse reflection simultaneously, so it is not possible to obtain the specular reflection characteristics of the image. This is also true when the reflected light is not directed vertically downward; if the variation in the angle of incidence is not suppressed, the diffuse reflection of light with a significantly shifted angle of incidence will be mixed into the specular reflection.

Therefore, in this embodiment, the size (length in the short direction) of the reflective surface 331 of the specular reflector 33 is made smaller than the size of the exit surface 313 to prevent the angle of incidence of light toward the original from changing significantly. As a result, compared to when the size of the reflective surface 331 of the specular reflector 33 is larger than the size of the exit surface 313, the size of the specular reflector 33 reduces the variation in the angle of incidence of light toward the original on the exit surface, and increases the proportion of specularly reflected light components in the components of light (original reflected light) reflected by the original 2 and heading toward the mirror 35.

It should be noted that there is also a method of narrowing the width of the light by shortening the short dimension of the exit surface for specular reflection, but when this method is used, a small amount of light enters the reading area, as shown in the light amount distribution D1 shown in Figure 5. In this embodiment, by shortening the short dimension A4 of the reflecting surface 331 as described above, the uniformity of the light is maintained compared to when an attempt is made to narrow the exit surface and thereby narrow the reflection area of the document.

In addition, in this embodiment, the diffuse reflected light and the specular reflected light share a common optical path, which results in a smaller reading device than when the diffuse reflected light and the specular reflected light have different optical paths. In addition, in this embodiment, the reflective surface 331 of the specular reflection reflector 33 is arranged in the direction in which the amount of light emitted by the specular reflection light emitting section 31 is the greatest. This prevents the specular reflected light from easily including areas with low amounts of light, compared to when the reflective surface 331 is arranged in a different direction, and increases the brightness of the generated image.

In addition, in this embodiment, the exit surface 313 is an example of a diffusion section that diffuses the emitted light. As a result, compared to a case where a diffusion section is not provided, the reflection area of the document is narrowed by shortening the short dimension of the reflection surface while maintaining uniformity in the amount of light by diffusing the light.

Furthermore, because the absolute amount of light of diffuse reflected light is smaller than that of specular reflected light, the difference in light amount is more likely to affect image quality. In this embodiment, the diffuse reflection exit surface 323 of the diffuse reflection light exit section 32 diffuses the emitted light to a greater extent than the specular reflection exit surface 313 of the specular reflection light exit section 31. This reduces the effect of diffuse reflection light on the image quality of the image it represents, compared to when the magnitude relationship of the degree of diffusion is reversed.

When creating a single image by combining a specular reflection image based on specularly reflected light and a diffuse reflection image based on diffusely reflected light, the image is generated based on the diffuse reflection image for characteristics other than gloss, which is more sensitive to specular reflection (characteristics such as color and sharpness that are more accurately indicated by diffuse reflection). In this embodiment, the diffuse reflection image generated in this way has less impact on image quality.

In addition, in this embodiment, by using the regular reflection reflector 33 to focus only a portion of the light, it is not necessary to add new parts, and the number of parts can be reduced.

In this way, when the light emitted by the specular reflection light emitting section 31 reaches the specular reflection reflector 33, only a portion of the light is directed toward the original document because the width of the reflective surface of the specular reflection reflector 33 is narrow, and the rest of the light passes behind the specular reflection reflector 33 and does not go in the direction of the original document. In other words, only a certain area of the irradiated light is directed toward the original document, and the other areas of the light do not. This is different from a configuration in which a filter or the like is provided over the entire optical path to adjust so that only a specific component of the light is directed toward the original document, or the amount of light is reduced by the light transmittance.

[2] Modifications The above-described embodiment is merely one example of the implementation of the present invention, and may be modified as follows. Furthermore, the embodiment and each modification may be combined and implemented as necessary.

[2-1] Reflector In the embodiment, the reflecting surface 331 of the specular reflector 33 is a flat surface, but the shape of the reflecting surface 331 is not limited to this. The reflecting surface 331 may be shaped to reflect the light emitted from the emission surface 313 of the light guide 312 toward the original 2 so that the light becomes convergent light. The specular reflector 33 is an example of the "reflective member" of the present invention.

Convergent light is light that converges toward a fixed focal point. The focal point may be set on the original, or may be set behind or in front of the original. The reflective surface 341 of the diffuse reflection reflector 34 may also be shaped to reflect the light emitted from the exit surface 323 of the light guide 322 toward the original 2 as convergent light.

Figure 12 shows the specular reflector 33b of this modified example. The specular reflector 33b has a concave reflecting surface 331b, which reflects the light emitted from the emission surface 323 toward the document 2 so that the light becomes convergent. Note that the shape is not limited to that shown in the figure, and other shapes such as concave, multi-faceted, and curved shapes are also possible.

In addition, in the first embodiment, the dimension W2 of the specular reflector 33 is narrower than the dimension W1 in the short direction A3 of the emission surface 313, but in the case of converging light, it does not need to be so narrow and may be the same or even longer. According to this modified example, the amount of light reflected by the original 2 is increased, for example, compared to when the emitted light is reflected toward the original 2 to become diverging light.

[2-2] Light-Blocking Section A light-blocking section may be provided.
Fig. 13 shows an enlarged view of the carriage 30c of this modified example. In addition to the components shown in Fig. 3, the carriage 30c includes a second blocking member 37 and a third blocking member 38. The second blocking member 37 is a plate-like member provided between the emission surface 323 of the diffuse reflection light emission section 32 and the reflection surface 331 of the specular reflection reflector 33, and prevents the light emitted from the emission surface 323 from directly reaching the reflection surface 331.

The provision of the second blocking member 37 prevents the occurrence of an event in which the image quality of the read image changes due to the light emitted for diffuse reflection being mixed with the light for specular reflection. The third blocking member 38 is a plate-shaped member provided between the emission surface 313 of the specular reflection light emission section 31 and the reflection surface 341 of the diffuse reflection reflector 34, and is formed to be integrated with the second blocking member 37.

The third blocking member 38 prevents the light emitted from the emission surface 313 from directly reaching the reflection surface 341. The third blocking member 38 is an example of the "second blocking section" of the present invention. The provision of the third blocking member 38 prevents the occurrence of an event in which the image quality of the read image changes due to the light emitted for specular reflection being mixed with the light for diffuse reflection.

[2-3] Light Entry Although the above embodiment describes an example in which multiple LEDs are provided in the longitudinal direction, a configuration in which a light guide extends in the longitudinal direction and a power LED is provided at the end of the light guide in the longitudinal direction may also be used. Also, light from multiple LEDs provided in the longitudinal direction may be directed directly at the document without using a light guide.

[2-4] Angle In the above embodiment, an example was shown in which the angle between the incident light and the reflected light was set small, but it is sufficient that the angle arrangement is such that the specular reflected light can be guided to the image sensor 60. In addition, in the above embodiment, an example was shown in which the member that irradiates the diffuse reflected light (the exit portion and the reflector) is closer to the document than the member that irradiates the specular reflected light, but the member that irradiates the diffuse reflected light may be farther from the document. In that case, for example, the incident angle and the exit angle of the specular reflected light are arranged to be inclined by, for example, 40° each with respect to the document. In this way, the optical path toward the document and the optical path from the document can be separated in distance from each other, making it easier to arrange the components.

Furthermore, although the exit portion for diffuse reflection is disposed on the same side of the optical path as the exit portion for regular reflection, they may be disposed on different sides.
14 is an enlarged view of a carriage 30d according to this modified example. The carriage 30d has a specular reflection light emitting portion 31d, a diffuse reflection light emitting portion 32d, a specular reflection reflector 33d, and a mirror 35d.

The specular reflection light emitting section 31d is disposed on a different side of the light path B1d than the diffuse reflection light emitting section 32d. The light emitted by the specular reflection light emitting section 31d is reflected by the specular reflection reflector 33d and enters the reading region R1. The diffuse reflection light emitting section 32d irradiates the reading region R1 of the original 2 with direct light without using a reflector. In the example of FIG. 14, the vertical height of the reading device relative to the original 2 is kept low compared to when the light source is disposed vertically below the reading region R1.

[2-5] Regarding the optical axis In the above embodiment, the optical axis C1 is located in the center of the optical path, but the optical axis C1 may be included and shifted to one side of the optical path, or the optical axis C1 may not be included in the optical path.
Fig. 15 shows an enlarged view of a carriage 30e of this modified example. In addition to the specular reflection light emitting portion 31e shown in Fig. 3, the carriage 30e includes a specular reflection light emitting portion 31e whose optical axis C1e faces a position shifted from the specular reflection reflector 33e.

The amount of light reflected by the left end region 331L and the right end region 331R of the reflecting surface 331e of the regular reflection reflector 33e will be described with reference to FIG.
Fig. 16 shows an example of the light amount distribution of the light emitted by the light emitting portion for specular reflection 31e. In the example of Fig. 16, a distribution D1e of the light amount when a plane located a predetermined distance from the light emitting portion for specular reflection 31e is viewed in a direction along the main scanning direction A1 is shown in a graph.

In the example of FIG. 16, the amount of reflected light at the left end region 331L and the amount of reflected light at the right end region 331R are shown, with the former being greater than the latter. Also, the optical axis C1e is not included in the reflected light at the specular reflector 33e. Note that the optical axis C1e may be included in the reflected light at the specular reflector 33e, but may be positioned so that it is closer to one side (either the left end region 331L or the right end region 331R).

In the example of Figure 15, the specular reflector 33e is positioned so that a difference in the amount of light occurs in the optical path that leads to the reading region R1 of the original, and the part with a large amount of light (the optical path that reflects at the left end region 331L) provides original reflected light that is closer to perfect specular reflection than the part with a small amount of light (the optical path that reflects at the right end region 331R).

In this way, when the optical path does not include the optical axis or is shifted to one side, there is a greater likelihood of there being some differences in the amount of light heading toward the original 2 compared to when the optical axis is at the center of the optical path. Therefore, it is better to make the left end region 331L, which has the greater amount of light, enter at an angle that is just right for regular reflection, and make the right end region 331R, which has less light, enter at an angle that is farther away from that.

For example, if only a portion of the emitted light is reflected by the specular reflector 33e, the end closest to the specular reflection angle should be the left end region 331L, and the end that is more deviated from the specular reflection angle should be the right end region 331R. By doing so, the proportion of specularly reflected light is increased compared to when the end closest to the specular reflection angle is the right end region 331R.

[2-6] Light emitting portion The shape of the light emitting portion is not limited to that described in the embodiment. For example, the light emitting portion may have an exit surface having a shape other than a rectangle. Furthermore, the light emitting portion may have two or more surfaces as the exit surface instead of one surface.

Figure 17 shows the specular reflection light emitting section 31f of this modified example. The specular reflection light emitting section 31f has a first exit surface 313-1 and a second exit surface 313-2, and emits light from each exit surface. In the example of Figure 17, the specular reflection light emitting section 31f is positioned so that the light emitted from the first exit surface 313-1 heads toward the specular reflection reflector 33, so the first exit surface 313-1 corresponds to the exit surface 313 of the specular reflection light emitting section 31 of the above embodiment. In other words, the specular reflection reflector 33 reflects a portion of the light from the first exit surface 313-1.

In the configuration of FIG. 17, the light emitted from the second exit surface 313-2 does not travel toward the specular reflector 33 or toward the document. In this modified example, light is emitted from the second exit surface 313-2, but the second exit surface 313-2 is not a surface designed for emitting light. The specular light emission section 31f may be positioned so that the light emitted from the second exit surface 313-2 travels toward the document.

In addition, two or more exit surfaces may be configured as exit surfaces corresponding to the exit surface 313 of the specular reflection light exit section 31 in the above embodiment. In that case, the light from the two exit surfaces that emit light toward the specular reflection reflector 33 may be directed toward the document by the specular reflection reflector 33 or the like.

[2-7] Equal-magnification optical system The above embodiment shows a reading device with a reduced optical system, but the present invention may be applied to a reading device with an equal-magnification optical system. The equal-magnification optical system is, for example, a CIS (Contact Image Sensor), and is composed of an LED light source that emits light, a SELFOC (registered trademark) lens that is an equal-magnification lens through which light reflected from the original 2 passes, and a light receiving element provided on the extension of the light source.

In the case of a CIS, since a SELFOC (registered trademark) lens is used, it may be difficult to set the angle between the incident light and the reflected light small, as in the above example. In that case, the incident light and the reflected light may be arranged so that the angles are the same, for example, so that they are tilted at 45 degrees with respect to the original. The incident light may also be limited by providing a slit between the LED light source and the original.

[2-8] Reading Device In the above embodiment, a reading device that reads a document placed on a document table has been described, but the present invention is not limited to this, and may be applied to, for example, an in-line sensor arranged in the transport direction of a document being transported, and a reading device that reads a sheet of paper being transported as a document. In the above embodiment, one document was read twice, one with the specular reflection light source turned on and the other with the diffuse reflection light source turned on.

In contrast, in the case of an in-line sensor, an image sensor can be provided for each of the specular reflection light source and the diffuse reflection light source, and reading can be performed at different positions in the transport direction, or the desired reading mode can be switched, for example, if priority is given to chromaticity, the diffuse reflection light source can be turned on, and if priority is given to gloss, the specular reflection light source can be turned on. Also, even if not all documents are read during transport, for inspection, etc., the diffuse reflection light source and specular reflection light source can be switched at intervals of a certain number of sheets rather than for full inspection.

[2-9] Output Device The results of reading by the image reading device 10 may be output.
Fig. 18 shows an image forming apparatus 70 according to this modified example. The image forming apparatus 70 includes the image reading apparatus 10 shown in Fig. 2. The stronger the specular reflection light in the reading area, the higher the glossiness of the reading area. Therefore, it is possible to determine by calculations using a CPU or the like which position on the document is glossy to what degree. In this case, the difference from the diffuse reflection light may also be used.

The image forming device 70 forms an image reflecting the result as image data using inkjet. In this way, the image forming device 70 outputs the degree of specular reflection based on the specular reflection light read by the image reading device 10. More specifically, the image forming device 70 outputs an image formed based on the degree of specular reflection read by the image reading device 10. Note that, in addition to outputting the image by the image forming device, the image may be processed according to the degree of gloss and output to a display device such as the screen of a PC or tablet.

10...image reading device, 20...image reading section, 21...original table, 22...original cover, 30...carriage, 31...light emitting section for regular reflection, 32...light emitting section for diffuse reflection, 33...reflector for regular reflection, 34...reflector for diffuse reflection, 35...mirror, 37...second blocking member, 38...third blocking member, 40...carriage, 41...mirror, 42...mirror, 50...imaging lens, 60...image sensor, 70...image forming device.

Claims (9)

an emission section having an emission surface that emits light and whose longitudinal direction is in the main scanning direction;
a reflecting section having a reflecting surface that reflects the light emitted from the exit surface and has a longitudinal direction in a main scanning direction, the lateral dimension of the reflecting surface being equal to or less than half the lateral dimension of the exit surface;
an image sensor that generates an image represented by the light reflected by the reflecting portion and specularly reflected by a document;
The reflecting surface is provided on a normal line passing through the center of the exit surface.
Reading device. The reading device according to claim 1 , wherein the reflecting surface is disposed in a direction in which the amount of light emitted by the emitting portion is greatest. 3. The reading device according to claim 1, wherein the exit surface is rectangular. 4. The reading device according to claim 1, wherein the light emitting section includes a light source that emits light, and a light guide having a planar light emitting surface that guides the light from the light source to the light emitting surface, the light guide having a portion whose cross section intersecting a plane perpendicular to the light emitting surface is rectangular. 5. The reading device according to claim 1, further comprising: a second emission section having a second emission surface that emits light and has a longitudinal direction in the main scanning direction, the second emission section being positioned so that an image represented by light emitted by the second emission section and diffusely reflected by the document is generated by the image sensor. The reading device according to claim 1 , wherein the light exit surface has a diffusion portion that diffuses the emitted light. The reading device according to claim 5 , wherein the exit surface for diffuse reflection of the second exit portion diffuses the emitted light to a greater extent than the exit surface for regular reflection of the exit portion. A reading device according to any one of claims 1 to 7,
an output device that outputs the degree of specular reflection based on the specular reflection light read by the reading device; An output device according to claim 8,
An image forming apparatus that outputs an image formed based on the degree of regular reflection read by the reading device.

Images