JPS648806B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color information reading device that separates and reads an image drawn on a document into pixels, and simultaneously performs color separation for each pixel.

Conventionally, this type of apparatus has been constructed as shown in FIG. In Fig. 1, 1 is a document on which an image is drawn in multiple colors, and 2 is the same number of pixels 3 (see Fig. 2) arranged in the main scanning direction (direction of arrow A) of this document 1. Reading elements (not shown) are arranged in one row to scan the original 1 in the main scanning direction (direction of arrow A).
4 is an imaging body that simultaneously reads a plurality of pixels 3 arranged in a row; 4 is a roller that conveys the original 1 at a constant speed in the sub-scanning direction [direction perpendicular to the drawing (see FIG. 2)]; numeral 6 is a lens for forming an image drawn on the original document 1 on the imaging body 2; numeral 6 is a parallel plane filter of a plurality of colors; for example, a red filter 7 and a cyan filter 8, which are complementary colors to each other;
(See Figure 1b).This disk 6 is arranged between the document 1 and the lens 5 so that the planes of the filters 7 and 8 are perpendicular to the optical axis. Installed on the optical path. Reference numeral 9 denotes a motor that rotates the disk 6 in synchronization with the reading operation of the image pickup body 2.

In the conventional example configured in this way, while the document 1 is conveyed in the sub-scanning direction [in the direction of arrow B (see FIG. 2)] by the roller 4, the document 1 is conveyed in the main scanning direction (direction of arrow A). Multiple pixels arranged in columns 3
When the light that has been color-separated sequentially for each row by the filters 7 and 8 of the rotating disc 6 enters each reading element (not shown) of the image pickup body 2, each reading element (not shown) of the image pickup body 2 The logic circuit (not shown) alternately outputs an electric signal proportional to the amount of light from each pixel 3 that has passed through the filter 7 and an electric signal proportional to the amount of light from each pixel 3 that has passed through the filter 8. ), by comparing these electrical signals for each pixel 3, the color possessed by each pixel 3 can be identified. By the way, in order to accurately separate the colors of each pixel 3, it is necessary to separate the range _S1 read by each reading element (not shown) of the image pickup body 2 through the filter 7 and the range S1 read by each reading element (not shown) of the image pickup body 2 through the filter 8. (not shown)
The read range _S2 must correspond to each pixel 3 as shown in FIG. 2a.
However, in this conventional example, since each pixel 3 is read while the original 1 is continuously conveyed by the roller 4, the original 1 is 1/1 Conveyed in the sub-scanning direction (direction of arrow B) by 2 pixels (however, when one pixel 3 is color-separated into m ways by sequentially arranging filters of m colors on the disk 6, 1/m pixels). and a range S ₁ (shown by a solid line) read by each reading element (not shown) of the image pickup body 2 through the filter 7 and a range S ₂ read by each reading element (not shown) of the image pickup body 2 through the filter 8. (indicated by a dotted line) is shifted by 1/2 pixel as shown in FIG.

Figure 3 shows the configuration of another conventional example.
The same numbers as in FIG. 1 indicate the same parts, and 10 and 11 are moved in the sub-scanning direction (direction of arrow B) so that the optical path length between the original 1 and the image pickup body 2 does not change. It is a flat mirror.

In the conventional example configured as described above, instead of conveying the document 1 using the roller 4 shown in FIG. This conventional example also had the same drawbacks as the conventional example shown in FIG.

FIG. 4 shows the configuration of a conventional example that eliminates the drawbacks of the conventional examples shown in FIGS. 1 and 3, and the same reference numerals as in FIG. 1 indicate the same parts. A plurality of filters of different colors, for example, filters 7 and 8, are individually fixed, and each of the filters 7 and 8 is provided with an imaging body 2 and a lens 5, thereby providing two lens systems.

In the conventional example configured in this way, since the same pixel 3 can be read simultaneously by each reading element (not shown) of the two image pickup bodies 2, each pixel 3
It is possible to accurately separate the colors of However, a plurality of imaging bodies 2 and a plurality of lenses 5
This increases the price of the color information reading device, and it also takes time and effort to adjust the optical axes of multiple lenses to match.Furthermore, increasing the number of color separations There was a rapid increase in the number of shortcomings such as:

In order to eliminate the drawbacks of the above-mentioned conventional examples, the present invention provides a lens with a circular plate attached with a plurality of filters or parallel plane glasses that differ in at least one element among plate thickness, refractive index, and incident angle of light rays. The present invention provides a color information reading device which prevents shifts in pixel reading positions caused by differences in pixel reading timing by installing the color information reading device tilted toward the axis. Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 5 shows the principle of the present invention, and shows the optical path of a ray that passes only through the air as L ₀ (shown by a solid line),
The optical path of a light beam incident at an angle θ ₁ on parallel plane glass 12 (indicated by a dotted line) with a plate thickness of t ₁ and a refractive index of n ₁ (1<n ₁ ) is L ₁ (indicated by a dotted line), and the plate thickness is t ₂ (however,
t ₁ ≦ t ₂ ) and a refractive index of n ₂ (however, 1<n ₁ ≦n ₂ ), an angle θ ₂ (however,
The optical path of the incident light ray (θ ₁ ≦ θ ₂ ) is defined as L ₂ (indicated by a dashed line), and the optical paths L ₀ , L ₁ and L ₂ of the incident light are made parallel to each other and refracted by the parallel plane glasses 12 and 13. When the optical paths L ₁ and L ₂ of the transmitted light are made to coincide with the optical path L ₀ of the light ray that has passed only through the air, the distance ΔX ₁ between the optical path L ₀ and the optical path L ₁ is generally ΔX ₁ = t ₁ · θ ₁ (1-1/n ₁ ) ...(1) The difference ΔY ₁ between the length of optical path L ₀ and the length of optical path L ₁ is generally expressed as ΔY ₁ =t ₁ (1-1/n ₁ ) ... (2), and the distance ΔX ₂ between the optical path L ₀ and the optical path L ₂ is generally expressed as ΔX ₂ = t ₂ · θ ₂ (1-1/n ₂ )... (3) Optical path L The difference ΔY ₂ between the length of the optical path L ₁ and the length of the optical path L ₂ is generally expressed as ΔY ₂ = t ₂ (1-1/n ₂ )...(4), so the difference between the optical path L ₁ and the optical path L ₂ is From equations ( ₁ ) _and ( _{3 )} , _the distance _{ΔX between} /n ₁ )] ...(5) The difference ΔY between the length of optical path L ₁ and the length of optical path L ₂ is calculated from equations (2) and (4) as follows: ΔY = ΔY ₂ −ΔY ₁ = [t ₂ (1 -1/n ₂ )] -[t ₁ (1-1/n ₁ )] ...(6) The difference in optical path length ΔY is usually the difference between the parallel plane glasses 12 and 13 of the lens. If it is placed in front, the depth of focus on the document 1 side will be the same as that of the image pickup body 2.
Since it is deep compared to the depth of focus on the side, it can be ignored. Therefore, by conveying the original 1 in a direction perpendicular to the optical axis of the lens 5 so that the optical path of the incident light beam emitted from the original 1 is parallel to the optical axis of the lens 5, and according to equation (5), by tilting The optical path of the transmitted light is refracted by a filter or parallel plane glass attached to the installed circular plate 6 by appropriately changing the value of at least one element among the thickness and refractive index of the glass and the angle of incidence of the incident light. By matching the rays, even if the rays enter the filter or parallel plane glass through different optical paths, the transmitted rays can be made to enter the reading element (not shown) of the image pickup body 2 through one optical path. Even if the pixel 3 moves in the sub-scanning direction, it is possible to prevent the reading position of the pixel 3 from shifting due to a difference in the reading timing of the pixel 3.

Next, embodiments of the present invention based on this principle will be described in detail. In addition, in FIGS. 6 to 9,
In order to facilitate understanding of the embodiments of the present invention, the refraction state of light rays in a filter or plane-parallel glass is illustrated ignoring optical theory; Needless to say, it is something that can be done.

FIG. 6 shows an embodiment of the present invention.
The same reference numerals as in FIGS. 1 and 5 indicate the same parts, and the original 1 is conveyed in the sub-scanning direction (direction of arrow B) perpendicular to the optical axis of the lens 5.
Filters 7 and 8 having different plate thicknesses and the same refractive index are placed on a disc 6 tilted toward the optical axis of the lens 5, so that the incident light rays are incident at the same angle of incidence. The plate thickness t ₂ of the filter 7 is larger than the plate thickness t ₁ of the filter 8.

In this embodiment configured as described above, when the thick filter 7 is placed on the optical axis of the lens 5, the imaging body 2 is
Optical path of the light beam incident on the reading element (not shown)
The light beam of pixel 3 emitted from point _P , which is far from the focal point O on the document 1 side of L 0 (indicated by a solid line) in the anti-sub-scanning direction (in the direction opposite to arrow B), enters the incident optical path L ₂ (indicated by a dashed line) ), and the transmitted light beam that is refracted and color-separated by this filter 7 passes through the transmitted optical path L ₂ (shown by a solid line) that coincides with the optical path L ₀ to read the image pickup body 2. When the thin filter 8 is placed on the optical axis of the lens 5, the light enters the reading element (not shown) of the image pickup body 2 when the filters 7 and 8 are not present. Point Q, which is close to the anti-sub-scanning direction (opposite direction of arrow B) from the focal point O on the document 1 side of the optical path L ₀ of the light beam incident on the
That is, the light beam of pixel 3 emitted from a position shifted by 1/2 pixel in the sub-scanning direction (direction of arrow B) from the far point P enters the filter 8 through the incident optical path L ₁ (shown by a dotted line), and , the transmitted light beam refracted and color-separated by this filter 8 enters the reading element (not shown) of the image pickup body _{2 through the transmitted optical path L 1 (} shown by a solid line) that coincides with the optical path L 0 . By rotating the disk 6 and replacing the filters 7 and 8 alternately on the optical axis of the lens 5, the reading element (not shown) of the image pickup body 2 moves in the sub-scanning direction (arrow B direction). Pixel 3 can be read alternately at point P and at point Q, which is shifted by 1/2 pixel from point P in the sub-scanning direction.
Note that the distance ΔX between point P and point Q is t ₁ < t ₂ , n ₁ = n ₂ =
n, θ ₁ = θ ₂ = θ, the dimension of one pixel in the sub-scanning direction is
If it is 125μ, then from equation (5), ΔX=ΔX ₂ −ΔX ₁ =θ[t ₂ −t ₁ )(1−1/n) =125/2=62.5(μ).

FIG. 7 shows another embodiment of the present invention, in which the same reference numerals as in FIG. , filters 7 and 8 with the same plate thickness and different refractive indexes are installed at the same angle, that is, so that the incident light rays enter at the same angle of incidence, and the refractive index n ₂ of the filter 7 is , is larger than the refractive index n ₁ of the filter 8.

In this embodiment configured in this manner, when the filter 7 is placed on the optical axis of the lens 5, the light ray from the pixel 3 at point P passes through the optical path _L2 and images are taken. Reading element on body 2 (not shown)
Also, when the filter 8 is on the optical axis of the lens 5, the light ray from the pixel 3 at the Q point, which is shifted from the P point by 1/2 pixel in the sub-scanning direction (in the direction of the arrow B), is on the optical path. Since the light enters the reading element (not shown) of the image pickup body 2 through _L1 , if the disk 6 is rotated and the filters 7 and 8 are alternately placed on the optical axis of the lens 5, the image pickup body 2 A reading element (not shown) can read each pixel 3 moving in the sub-scanning direction (arrow B direction) alternately at points P and Q. Note that the distance ΔX between point P and point Q is t ₁ = t ₂ = t, n ₁ < n ₂ , θ ₁ =
Assuming that θ ₂ =θ and the dimension of one pixel in the sub-scanning direction is 125μ, ΔX=θ·t(1/n ₁ −1/n ₂ )=62.5(μ) from equation (5).

FIG. 8 shows still another embodiment of the present invention, in which the same reference numerals as in FIG. 6 indicate the same parts. 6, filters 7 and 8 having the same plate thickness and refractive index are installed at different angles, that is,
The filter is attached so that the incident light rays are incident at different angles of incidence, and the angle at which the filter 7 is attached to the disk 6 is larger than the angle at which the filter 8 is attached to the disk 6. The angle of incidence is greater than the angle of incidence on the filter 8.

In this embodiment configured in this manner, when the filter 7 is placed on the optical axis of the lens 5, the light ray from the pixel 3 at point P passes through the optical path _L2 and images are taken. Reading element on body 2 (not shown)
and when the filter 8 is on the optical axis of the lens 5, the light ray from the pixel 3 at point Q, which is shifted from point P by 1/2 pixel in the sub-scanning direction (direction of arrow B), follows the optical path L. ₁ and enters the reading element (not shown) of the image pickup body 2. Therefore, by rotating the disc 6 and alternately replacing the filters 7 and 8 on the optical axis of the lens 5, the light of the image pickup body 2 can be read. A reading element (not shown) scans each pixel 3 moving in the sub-scanning direction (direction of arrow B) at P
It can be read alternately at point and Q point. still,
The distance θX between point P and point Q is t ₁ = t ₂ = t, n ₁ = n ₂ =
If n, θ ₁ < θ ₂ , and the dimension of one pixel in the sub-scanning direction is 125 μ, then from equation (5), θX = t (θ ₂ − θ ₁ ) (1-1/n) = 62.5 (μ) .

FIG. 9 shows still another embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same parts, and 1 indicates the sub-scanning direction perpendicular to the optical axis of the lens 5. The document 12 is tilted toward the optical axis of the lens 5 and is installed in the direction of the arrow B. Parallel plane glasses 14 are alternately attached to the openings 13 provided in the disk 12. [See Figure 9b]. 15 is a motor that rotates in synchronization with the motor 9, and this motor 15 rotates the parallel plane glass 1 when the filter 7 is placed on the optical axis of the lens 5.
4 is placed on the optical axis of the lens 5, and when the filter 8 is placed on the optical axis of the lens 5, the disc 12 is rotated so that the aperture 13 is placed on the optical axis of the lens 5.

In this embodiment configured as described above, when the filter 7 and the parallel plane glass 14 are placed on the optical axis of the lens 5, the reading element (not shown) of the image pickup body 2 The light beam of pixel 3 is emitted from point P, which is shifted by 1/2 pixel in the anti-sub-scanning direction (the direction opposite to arrow B) from the focal point O on the document 1 side of the optical path L ₀ (shown by the solid line) of the light ray that enters the teeth,
Passing through the incident light path L ₁ (shown by the dotted line), it is first color-separated by the filter 7 and then refracted by the plane-parallel glass 14, followed by the transmitted light path L ₁ (which coincides with the light path L ₀ ). It enters the reading element (not shown) of the image pickup body 2 through the filter 8 (shown with a solid line).
When the aperture 13 is on the optical axis of the lens 5, the light beam of the pixel 3 emitted from the point O enters the filter 8 through the incident optical path _L0 (shown as a solid line), and The transmitted light beams separated by color are incident on the reading element (not shown) of the image pickup body 2, so by rotating the disc 6, the filters 7 and 8, the parallel plane glass 14, and the aperture 13 are alternately connected. If it is replaced on the optical axis of the lens 5, the reading element (not shown) of the image pickup body 2 will move in the sub-scanning direction (direction of arrow B).
Each pixel 3 that moves can be read alternately at point P and point O. In addition, the distance ΔX between point O and point P
From equation (1), the thickness of the parallel plane glass 14 is t,
If the refractive index of the plane-parallel glass 14 is n, and the angle of incidence of the light beam _L1 on the plane-parallel glass 14 is θ, then from equation (1), ΔX=t·θ(1-1/n).

In the embodiment of the present invention, the image drawn on the document 1 is separated into two colors.
To separate the colors into colors, either m-color filters are arranged on a disk, or (m-1) pieces of parallel flat glass are arranged in m apertures of the disk, and the intervals between each reading position are set as follows.
It may be 125/m (μ).

As explained above, according to the present invention, the discs tilted toward the optical axis of the lens have different colors and differ in at least one element among the plate thickness, refractive index, and incident angle of light rays. At least one of a plurality of filters or plate thicknesses, refractive indexes, and incident angles of light rays.
By arranging multiple parallel plane glasses with different color elements, even if the document is conveyed in the sub-scanning direction while filters of different colors are being replaced, only the incident optical path on the document side will be shifted and the transmitted optical path on the image pickup side will be changed. Since the document can be read in a constant state, each pixel can be accurately separated into colors, which has the advantage of being able to accurately separate each pixel.Also, since only one image pickup body and lens are required, the price of the color information reading device is low, and optical It has the advantage of being easy to make adjustments. Furthermore, the embodiment shown in FIG. 9 has the advantage that by adding the device of the present invention to a conventional color information reading device, the drawbacks of the conventional device can be easily overcome.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a conventional color information reading device;
3 and 4 are configuration diagrams of a conventional color information reading device. FIG. 5 is an explanatory diagram of the principle of the present invention. There is a configuration diagram of an embodiment. 1... Original, 2... Imaging body, 3... Pixel, 4...
...roller, 5...lens, 6, 12...disk,
7, 8... Filter, 9, 15... Motor, 1
0, 11...Plane mirror, 13...Aperture, 14...Parallel plane glass.

Claims (1)

[Scope of Claims] 1. A lens that forms an image of a document on a reading element of an image pickup body, a disk tilted toward the optical axis of the lens, a drive device that rotates the disk, and a drive device that rotates the disk. A plurality of filters are arranged on a plate and differ in at least one element among the plate thickness, refractive index, and attachment angle to the disc, and are different in color, and the filters are arranged on a plate to form a plurality of optical paths parallel to the optical axis of the lens. A color information reading device characterized in that the light rays incident on the filter are color-separated and refracted by the filter, and the light rays transmitted through the filter are made to coincide with one optical path. 2. A lens that forms an image of a document on a reading element of an image pickup body, a first disk provided perpendicular to the optical axis, and a first drive device that rotates the first disk. , a plurality of filters of different colors arranged on the first disk, a second disk tilted toward the optical axis of the lens, and a second drive device in synchronization with the first drive device. a second drive device for rotating a disc; and at least one of plate thickness, refractive index, and attachment angle to the second disc arranged on the second disc;
The first disk and the second disk are rotated in synchronization to pass the filter through a plurality of optical paths parallel to the optical axis of the lens. and the light rays incident on the parallel plane glass are color separated by the filter, and are refracted by the parallel plane glass, so that the light rays transmitted through the parallel plane glass are made to coincide with one optical path. Color information reading device. 3. The color information reading device according to claim 2, wherein the second circular plate is provided with at least one opening in which the parallel flat glass is not arranged.