JPH10112778A - Color image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: Not to make the switching function of color separation filters complicated and also make an entire device small and thin. SOLUTION: Even though a rotary shaft 17 is orthogonally arranged to the optical axis of optical path, this device does not need a broad space where a conventional disk like rotary filter, conventional flat plate-shaped mobile filter, etc., are arranged because the mounting plate 22 of the shaft 17 is provided with each color separation filter of three colors 16R, 16G and 16B which have the same distance from the rotational center and are placed in the same intervals. The entire device can be made small and thin, the filters 16R, 16G and 16B can easily be replaced because the shaft 17 is just rotated in synchronization with the image reading speed of an image pickup device 15. The device can be inexpensive and also an image can be read at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color image reading device.

[0002]

2. Description of the Related Art Conventionally, a color image reading apparatus for reading a color original has a structure shown in FIG. 6 or FIG. That is, the color image reading apparatus shown in FIG. 6 uses a fan-shaped color separation filter 1R, 1G, 1B for separating white light into three colors of red (R), green (G), and blue (B). The rotary filter 1 is arranged in the shape of a circle. The rotary filter 1 is disposed on the optical path between the document surface 2 of the color document and the image sensor 3 at right angles to the optical axis 4. Each color separation filter 1 is rotated by a motor or the like in synchronization with the reading speed of the image sensor 3.
R, 1G, and 1B are sequentially switched, the light from the document surface 2 is separated into three colors of R, G, and B, and the light of each of the separated colors is sequentially condensed by the lens 5 onto the image sensor 3, thereby obtaining each color. Are sequentially received by the image sensor 3 to obtain color image information.

In the color image reading apparatus shown in FIG. 7, striped color separation filters 6R, 6G and 6B for separating white light into three colors of R, G and B are sequentially arranged in a flat plate shape. The moving filter 6 is provided.
Are arranged on the optical path between the original surface 2 of the color original and the image sensor 3 so as to be orthogonal to the optical axis 4, and this moving filter 6 is formed of stripe-like color separation filters 6R, 6G, 6B.
Are linearly moved in synchronization with the reading speed of the image sensor 3 along the arrangement direction of the image sensor 3 to separate the light from the document surface 2 into three colors of R, G, and B, and convert the separated light of each color into a lens. 5, the light is sequentially condensed on the image sensor 3, and the light of each color is sequentially received by the image sensor 3 to obtain color image information.

[0004]

However, in such a color image reading apparatus, in any case, the disk-shaped rotary filter 1 or the plate-shaped moving filter 6 is made orthogonal to the optical axis 4 on the optical path. The filters 1 and 6 need to be rotated or linearly moved, so that a large space is required for operably disposing the filters 1 and 6, thereby reducing the size and thickness of the entire apparatus. There is a problem that cannot be achieved. In particular, in the latter color image reading device, the moving filter 6 is moved linearly so that each of the striped color separation filters 6R, 6G, 6
B, the original surface 2 of the color original is changed.
When the image sensor 3 sequentially reads line by line, the moving filter 6 must be linearly moved at high speed, so that a special driving source such as a linear motor or a special cam mechanism is required, and the color separation filter 6R, There is a problem that the switching mechanism of 6G and 6B becomes complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color separation filter switching mechanism that is not complicated and that the entire apparatus can be reduced in size and thickness.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a reading means for receiving light from an image and reading it as image information, and a rotatable orthogonal to the optical path on an optical path between the image and the reading means. And a rotating shaft provided with a plurality of different color separation filters sequentially along the rotation direction at a position corresponding to the outer peripheral surface thereof. Therefore, according to the present invention, a plurality of different color separation filters are provided at locations corresponding to the outer peripheral surface of the rotating shaft. Therefore, even if the rotating shaft is provided orthogonal to the optical path, a conventional disk-shaped rotating filter is provided. This eliminates the need for a large space for disposing a filter or a flat moving filter, so that the entire apparatus can be reduced in size and thickness, and the rotating shaft can be synchronized with the image reading speed of the reading unit. Only needs to be rotated, so that the switching mechanism of the color separation filter is simple and inexpensive.

In this case, if an infrared filter that cuts infrared rays on the rotation axis is provided corresponding to each of the plurality of different color separation filters, the infrared light can be used to reduce the light from the image. Among them, the infrared rays can be cut, and thus the heating of the reading means by the infrared rays can be prevented, whereby the reading accuracy of the reading means can be improved, and the life of the reading means can be prolonged. High quality products can be obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a color image reading apparatus according to the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of a color image reading apparatus, and FIG. 2 is a perspective view schematically showing the internal structure thereof. In these figures, reference numeral 10 denotes a main body case. A light source 11 is disposed on one side (the left side in FIG. 1) in the main body case 10. The light source 11 includes a cold cathode tube or the like, and has a structure that emits white light. A reflector 12 is arranged on the outer periphery of the light source 11.
The reflector 12 reflects light from the light source 11 toward an opening 10 a provided at the bottom of the main body case 10,
Thus, the color document 13 arranged below the opening 10a is configured to be irradiated with light.

Above the opening 10a in the main body case 10, of the reflected light of the light applied to the color document 13, the light incident on the main body case 10 through the opening 10a is reflected by the other end of the main body case 10. A reflection mirror 14 that reflects light toward the right end side in FIG. 1 is disposed. On the other side of the main body case 10, an image sensor (reading means) 15 for receiving light from the color document 13 reflected by the reflection mirror 14 is arranged. This image sensor 15
Has a photosensitive portion and a charge transfer portion, and has a structure in which a large number of light receiving pixels are arranged in a line. A rotating shaft 17 having three color separation filters 16R, 16G, and 16B on the optical path between the reflection mirror 14 and the imaging device 15 in the main body case 10 as shown in FIGS. Each color separation filter 16R, 1
A condensing lens 18 for condensing light transmitted through 6G and 16B on each light receiving pixel of the image sensor 15 is provided. In addition, a circuit board 19 for driving the light source 11 is provided below the optical path between the reflection mirror 14 and the rotation shaft 17 in the main body case 10.

The rotating shaft 17 is rotatably provided on the optical path in a state perpendicular to the optical axis O. The rotating shafts 17 are provided at the opposite ends of the shaft portions 20 at both ends, respectively.
1 is provided, and a mounting plate 22 is stretched between the outer peripheral portions of the support plates 21. The color separation filters 16R,
16G and 16B are provided along the rotation direction, and are configured to rotate in synchronization with the reading speed of the image sensor 15 by a motor (not shown). In this case, the mounting plate 22
As shown in FIGS. 3 (a) to 3 (c), a hexagonal cylinder is divided into half vertically and is stretched over half of the outer peripheral portion of the support plate 21 on both sides, and every 60 ° Are provided with filter mounting portions, and each filter mounting portion has an elongated opening 23 provided in the axial direction. Each opening 23 is
This is for transmitting the light reflected by the reflection mirror 14, and also serves as a stop, and has a width of about 30 ° about the center of rotation, and is adjacent thereto. The distance between the openings 23 is also about 3 around the center of rotation.
The structure is formed at intervals of 0 °.

The three color separation filters 16R, 16R,
6G and 16B convert the reflected light from the color document 13 reflected by the reflection mirror 14 into R,
The image is separated into three colors of G and B. That is, the R color separation filter 16R transmits red wavelength light and absorbs other visible light, and the G color separation filter 16G transmits green wavelength light and filters the other visible light. The color separation filter 16B for B absorbs the blue wavelength light and absorbs other visible light. Each of these color separation filters 16R, 16G, and 16B is provided on each filter mounting portion of the mounting plate 22 at the same distance from the center of rotation and at equal intervals in order to cover the respective openings 23, and together with the rotating shaft 17, Rotate each color separation filter 16R, 16G, 16B
Is sequentially moved on the optical path.

In such a color image reading apparatus, when the light source 11 is turned on and the main body case 10 is moved on the surface of the color document 13, light from the light source 11 is transmitted to the opening 10.
a to the original surface of the color original 13, the light reflected from the original surface enters the main body case 10 through the opening 10 a, and the incident light is reflected toward the image sensor 15 by the reflection mirror 14. . The reflected light is applied to each of the three color separation filters 16R,
6G and 16B, for example, in the state shown in FIG. 3A, the light enters the color separation filter 16B for B,
The blue color light is selected and transmitted by the color separation filter 16B, and the other visible light is absorbed. And this B
Light of the blue wavelength transmitted through the color separation filter 16B is condensed on each light-receiving pixel of the image sensor 15 by the condensing lens 18 through the opening 23 of the mounting plate 22. The light is received and only the blue wavelength, that is, blue image information of the light from the color document 13 is read.

When the blue image information is read by the image pickup device 15 in this manner, the rotating shaft 17 is rotated by 60 ° by the motor in synchronism therewith, and the next G color separation filter 16G is shown in FIG. It moves on the optical path as shown in b). For this reason, the reflected light from the color document 13 reflected by the reflection mirror 14 is turned into a color separation filter 16 for G this time.
The green wavelength light is selected and transmitted by G, and the transmitted green wavelength light is received by each light receiving pixel of the image sensor 15 via the condenser lens 18. As a result, the green wavelength, that is, green image information of the color document 13 is read. Similarly, when the green image information is read, the rotation shaft 17 is further rotated by 60 ° in synchronization with this, and the next color separation filter 1 for R is used.
6R moves on the optical path as shown in FIG.
The red wavelength light is selected and transmitted by the color separation filter 16R for R, and the transmitted red wavelength light is received by each light receiving pixel of the image sensor 15, whereby the color original 1
3 red wavelengths, that is, red image information is read.

Thereafter, although not shown, when the red image information is read, the rotating shaft 17 is further synchronized with the reading.
Is rotated by 60 °, the reflected light reflected by the reflection mirror 14 passes through the opening 23, and then the color separation filter 16B for B
The light of the blue wavelength is selected and transmitted, and the transmitted light of the blue wavelength is received by each light receiving pixel of the image sensor 15, whereby the blue image information is read. Similarly, when the blue image information is read, the rotation axis 17 further rotates by 60 ° in synchronization with this, and the light from the reflection mirror 14 passes through the opening 23 and then passes through the next G color separation filter 16G. Green wavelength light is selected and transmitted, and the green wavelength light is received by each light receiving pixel of the image sensor 15, whereby green image information is read. When the green image information is read, the rotation axis 17 is further rotated by 60 ° in synchronization with this.
After rotation, the light from the reflection mirror 14 passes through the opening 23, and the light of the red wavelength is selected and transmitted by the next color separation filter 16R for R. Light is received, whereby red image information is read. In this way, every time the rotation shaft 17 rotates half a rotation (180 ° rotation), the color information of one line of the image of the color document 13 can be read, and this reading operation is sequentially repeated for each line of the color document 13. Thus, the entire color document 13 can be read.

In this color image reading apparatus, for example, a rotary shaft 17 for reading an image of 30 mm per second is used.
The rotation speed will be specifically described. In this case, when the reading width of one line of the image by the image sensor 15 is set to 400 dots per inch (400 dpi), one inch is 25.4 mm.
The line reading width (mm) is 25.4 / 400 = 0.0635 (mm). The reading time (s1) of one line for reading an image of 30 mm per second at this reading width is 0.0635 / 30 = 0.0021667 (s). The reading light time (s2) of the image sensor 15 during one rotation of the rotating shaft 17 is equal to the color separation filters 16R, 1R.
Since the light is transmitted twice through 6G and 16B, 0.0021667 × (3 × 2) = 0.0127 (s). Reading time per rotation of the rotating shaft 17 (s2)
Is converted into the number of rotations per minute (rpm), 60 ÷ 0.0127 = 4724.4 (rpm). To read an image of 30 mm per second, the rotating shaft 17 is rotated at about 4724 rpm. I just need.

As described above, according to this color image reading apparatus, the color separation filters 16R, 16G, 3G,
Since the rotary shaft 16B is provided, even if the rotary shaft 17 is provided to be orthogonal to the optical axis O of the optical path, a large space for disposing the conventional rotary filter 1 in the form of a disk, the movable filter 6 in the form of a flat plate, and the like is provided. It is not necessary, so that the entire apparatus can be reduced in size and thickness, and it is only necessary to rotate the rotating shaft 17 in synchronization with the image reading speed of the image sensor 15. 16R, 16
Switching between G and 16B can be easily performed, a low-cost one can be obtained, and an image can be read at high speed.

Next, with reference to FIGS. 4A to 4C, a second embodiment of the color image reading apparatus of the present invention will be described. The same parts as those in the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof will be omitted. This color image reading apparatus is provided with a rotation axis rotatably provided on a light path between a reflection mirror 14 for reflecting light reflected from a color document 13 and an image pickup device 15 in a state orthogonal to an optical axis O thereof. The structure is exactly the same as that of the first embodiment except that the structure of 30 is different. That is, the rotating shaft 30 is provided with regular hexagonal support plates 21 at opposite ends of the shaft portions 20 at both ends, and as shown in FIGS. Hexagonal cylinder 31 between
Are attached to each of the six flat portions of the cylindrical body 31. Elongated openings 23 are provided along the axial direction, and the three color separation filters 16R and 16R are provided in three continuous flat portions.
G and 16B are sequentially provided along the rotation direction, and an infrared filter 32 for cutting infrared light is provided on each flat portion facing the G and 16B, and the reading speed of the image sensor 15 is reduced by a motor (not shown). It is structured to rotate synchronously.

In such a color image reading apparatus, the first
As in the embodiment, when the light from the light source 11 is reflected on the document surface of the color document 13 and the reflected light is reflected toward the image pickup device 15 by the reflection mirror 14, the reflected light is provided on the rotating shaft 30. Each of the three color separation filters 16R,
In the state shown in FIG. 4A, one of 16G and 16B is incident on the color separation filter 16B for B, and light of a blue wavelength is selected and transmitted by the color separation filter 16B for B, The transmitted blue wavelength light is incident on the opposite infrared filter 32 through each opening 23 of the cylindrical body 31, the infrared filter 32 cuts the infrared light, and the blue wavelength light from which the infrared light has been cut is collected. The light is received by each light receiving pixel of the image sensor 15 via the lens 18.
Thereby, the blue image information of the color document 13 is read.

As described above, when the image is read by the image pickup device 15, the rotating shaft 30 is rotated by 60 ° in synchronization with the image, and the next G color separation filter 16G is shown in FIG. As described above, the reflected light from the color document 13 is incident on the G color separation filter 16G as described above, and the green color light is selected by the G color separation filter 16G. The transmitted green wavelength light is incident on the infrared filter 32 on the opposite side, the infrared filter 32 cuts the infrared light, and the green wavelength light from which the infrared light has been cut is passed through the condenser lens 18 to the image sensor. The light is received by each of the 15 light receiving pixels. Thereby, the green image information of the color document 13 is read. Similarly, when the green image information is read, the rotation axis 30 is further rotated by 60 ° in synchronization with this, and the next color separation filter 1 for R is used.
Since 6R moves on the optical path as shown in FIG. 4 (c),
The light of the red wavelength is selected and transmitted by the color separation filter 16R for R, and the transmitted light of the red wavelength is incident on the infrared filter 32 on the opposite side.
The infrared rays are cut off by the light receiving elements, and are received by the respective light receiving pixels of the image sensor 15. Thereby, the red image information of the color document 13 is read.

After that, when the rotating shaft 30 is further rotated by 60 ° in synchronization with the reading of the image, the reflecting mirror 14
The infrared filter 32 is located on the side, and the color separation filter 16B for B is located on the opposite side. At this time, the reflected light from the color document 13 reflected by the reflection mirror 14 is first cut by the infrared filter 32 to cut off the infrared light, and the cut light is incident on the B color separation filter 16B. The light of the blue wavelength is selected and transmitted by the color separation filter 16B, and the transmitted light is received by each light receiving pixel of the image sensor 15. Thereby, the blue image information of the color document 13 is read. Similarly,
According to the rotation of the rotation shaft 30, the color separation filter 16 for G
The green image information of the color original 13 is read by G, and the color original 1 is read by the color separation filter 16R for R.
3 is read. By repeating this reading operation sequentially for each line of the color document 13, the entire color document 13 can be read.

As described above, according to the color image reading apparatus, the same operation and effect as those of the first embodiment can be obtained. Filter 16R, 16
G and 16B are respectively provided, so that infrared rays can be cut from reflected light from the color original 13 by each infrared filter 32, and therefore, heating of each light receiving pixel of the image sensor 15 by infrared rays can be prevented. Thus, the reading accuracy of the image sensor 15 can be improved, the life of the image sensor 15 can be extended, and a high quality device can be obtained.

Next, a third embodiment of the color image reading apparatus of the present invention will be described with reference to FIGS. 5 (a) to 5 (c). Also in this case, the same portions as those of the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals, and the description thereof will be omitted. This color image reading apparatus is provided with a rotation axis rotatably provided on a light path between a reflection mirror 14 for reflecting light reflected from a color document 13 and an image pickup device 15 in a state orthogonal to an optical axis O thereof. No. 1 except that the structure of 35 is different
The structure is exactly the same as that of the embodiment. That is,
The rotary shaft 35 is provided with equilateral triangular support plates 36 at opposite ends of the shaft portions 20 at both ends, respectively, as shown in FIGS.
As shown in (c), three mounting plates 37 are stretched between the outer peripheral portions of each support plate 36 with a gap S therebetween.
7 are provided with elongated openings 23 along the axial direction, respectively, and the three color separation filters 16R, 16R,
6G and 16B are provided at equal distances from the center of rotation in order along the rotation direction, and are configured to rotate in synchronization with the reading speed of the image sensor 15 by a motor (not shown).

In such a color image reading apparatus, the first
As in the embodiment, when the light from the light source 11 is reflected on the document surface of the color document 13 and the reflected light is reflected toward the image sensor 15 by the reflection mirror 14, the reflected light is provided on the rotation shaft 35. Each of the three color separation filters 16R,
In the state shown in FIG. 5A, one of 16G and 16B is incident on the color separation filter 16B for B, and blue color light is selected and transmitted by the color separation filter 16B for B, The transmitted blue wavelength light exits from the gap S on the opposite side through the opening 23 of the mounting plate 37, and the emitted blue wavelength light is received by each light receiving pixel of the image sensor 15 via the condenser lens 18. Thereby, the blue image information of the color document 13 is read.

When the image is read by the image pickup device 15 in this manner, the rotating shaft 35 is driven by the motor in synchronization with the image.
After being rotated by 20 °, the color separation filter 16G for G moves on the optical path as shown in FIG. 5B, so that the reflected light from the color document 13 is converted to the color separation filter 16G for G in the same manner as described above. , And the green color light is selected and transmitted by the G color separation filter 16G, and the transmitted green wavelength light is received by the image sensor 15, whereby the color original 1
The green image information of No. 3 is read. Similarly, when the green image information is read, the rotation axis 35 is further rotated by 120 ° in synchronization with this, and the next color separation filter 16 for R is rotated.
Since R moves on the optical path as shown in FIG. 5C, red wavelength light is selected and transmitted by the color separation filter 16R for R, and the transmitted red wavelength light is transmitted to the image sensor 15 by the image sensor 15. The light is received, whereby the red image information of the color document 13 is read. This reading operation is sequentially repeated for each line of the color original 13, whereby the color original 1 is read.
3 can be read.

As described above, in this color image reading apparatus, similarly to the first embodiment, the three color separation filters 16R, 16G, 16B of the three colors are mounted on the mounting plate 37 of the rotating shaft 35 at equal distances and at equal intervals from the center of rotation. Is provided, even if the rotation axis 35 is provided perpendicular to the optical axis O of the optical path, a large space for disposing the disk-shaped rotary filter 1 and the plate-shaped movable filter 6 as in the related art is required. Therefore, it is possible to reduce the size and thickness of the entire apparatus, and it is only necessary to rotate the rotating shaft 35 in synchronization with the image reading speed of the image sensor 15, so that each of the three color separation filters 16R , 16G, and 16B can be easily switched, a low-cost one can be obtained, and an image can be read at a high speed.

In the third embodiment, the rotating shaft 35
Is rotated every 120 °, but is not limited thereto, and the rotating shaft 35 may be rotated every 60 °. In this case,
The light from the reflection mirror 14 is made incident on the color separation filter,
This color separation filter selects and transmits light of a specific wavelength,
The transmitted light is passed through the gap S of the mounting plate 37 to the image sensor 15.
The light from the reflection mirror 14 is turned on the mounting plate 37 by rotating the rotating shaft 35 by 60 ° after reading the light.
After passing through the gap S of the color separation filter,
The light of a specific wavelength may be selected by the color separation filter and read by the image sensor 15. In the first to third embodiments, the color separation filters 16R, 16G, R, G, and B for the rotation shafts 17, 30, and 35 are respectively provided.
Although the case where 16B is provided has been described, the present invention is not limited to this.
Four or more color separation filters may be provided. In the first to third embodiments, the openings 23 of the rotary shafts 17, 30, and 35 are formed to have a simple elongated shape. However, the present invention is not limited to this. You may form in the shape which made the width | variety of both ends wider than width.

[0027]

As described above, according to the present invention, the rotation axis is provided on the optical path from the image to the reading means so as to be rotatable perpendicularly to the optical path, and the rotation axis corresponds to the outer peripheral surface of the rotation axis. Since a plurality of different color separation filters are sequentially provided along the rotation direction at a position where the rotation is made, even if the rotation axis is provided orthogonal to the optical path, a conventional disk-shaped rotation filter or a plate-shaped movement filter as in the related art can be used. A large space for disposition is not required, so that the size and thickness of the entire apparatus can be reduced, and the rotating shaft only needs to be rotated in synchronization with the image reading speed of the reading means. It is possible to obtain a simple and inexpensive switching mechanism for the decomposition filter.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a color image reading apparatus of the present invention.

FIG. 2 is a perspective view schematically showing the internal structure of FIG. 1;

3A and 3B are enlarged cross-sectional views of a rotation axis of FIG. 2, wherein FIG. 3A is an enlarged cross-sectional view in which a color separation filter for B is located on an optical path, and FIG. 3B is a color separation filter for G on an optical path. And (c) is an enlarged cross-sectional view in a state where a color separation filter for R is positioned on the optical path.

FIG. 4 is an enlarged cross-sectional view of a rotation axis in a color image reading apparatus according to a second embodiment of the present invention, and FIG.
Enlarged sectional view of the state where the color separation filter for
(B) is an enlarged sectional view of a state where a color separation filter for G is located on the optical path, and (c) is an enlarged sectional view of a state where a color separation filter for R is located on the optical path.

FIGS. 5A and 5B are enlarged cross-sectional views of a rotary shaft in a color image reading apparatus according to a third embodiment of the present invention, wherein FIG.
Enlarged sectional view of the state where the color separation filter for
(B) is an enlarged sectional view of a state where a color separation filter for G is located on the optical path, and (c) is an enlarged sectional view of a state where a color separation filter for R is located on the optical path.

FIG. 6 is a schematic configuration diagram showing an example of a conventional color image reading apparatus.

FIG. 7 is a schematic configuration diagram showing another example of a conventional color image reading apparatus.

[Explanation of symbols]

 Reference Signs List 13 color original 15 image sensor 16R color separation filter for red 16G color separation filter for green 16B color separation filter for blue 17, 30, 35 rotation axis O optical axis

Claims (2)

[Claims] 1. Reading means for receiving light from an image and reading it as image information, and provided on an optical path between the image and the reading means so as to be rotatable orthogonally to the optical path and having an outer periphery. A rotating shaft in which a plurality of different color separation filters are sequentially provided along a rotation direction at a position corresponding to the surface. 2. The color image reading apparatus according to claim 1, wherein an infrared filter for cutting infrared rays is provided on the rotation shaft in correspondence with each of the plurality of different color separation filters.