JPH0346864A - Image reader - Google Patents

Abstract

PURPOSE:To increase the range of variable magnification greatly by retracting a 1st reflecting optical member from a 1st optical path, advancing an optical translucent document in a plane intersecting orthogonally with the traveling direction of the light in the 1st optical path, and making transmitted light incident on a 2nd reflecting optical member. CONSTITUTION:When an image forming lens L is set at a specific position in the 1st optical path to constitute an enlargement optical system, an image is read by moving a translucent recording medium OL which is already recorded for subscanning without moving the optical system. A reflecting mirror M1 is moved out of the optical path of the light from the light source LS so as to use the light source LS to be served also as a light source for lighting the translucent recording medium OL which is already recorded, and the translucent recording medium OL which is already recorded is moved into the passage of the light from the light source LS for subscanning to read the image.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image reading device, and particularly to an image reading device that can read images of a wide range of sizes with high precision.

(Prior art) Figure 7 shows that the distance between the reading position in the target image and the line image sensor fixedly provided at a specific position is always kept constant. 7 is a diagram showing a schematic configuration of a conventional image reading device using a moving optical system configured as shown in FIG. Light source, Ml, M2. M3 is a reflecting mirror, L is an imaging lens, and LIS is a line image sensor.

MA is the reflecting mirror M2. This is a reflecting mirror member made of M3.

In the above-mentioned image reading device shown in FIG. 7, the light source LS and the reflecting mirror M1 are integrated during the reading operation of one image, and the light source LS and the reflecting mirror M1 are integrated to scan the area below the document table OP, for example, within the range indicated by Ql in FIG. When moving parallel to the document table OP at the first speed V from the position M1 shown by the solid line to the position Ml' shown by the dotted line,
The above-mentioned reflecting mirror M2. The reflecting mirror member MA made of M3 moves below the document table OP parallel to the document table OP from the position MA indicated by the solid line in the figure at a moving speed V/2 which is 1/2 of the first moving speed V mentioned above. Position MA'(M2',
M3') so that the distance between the reading position in the image being read and the line image sensor fixedly provided at a specific position is always kept constant. It is configured.

Then, the reflected light from the original on the original platen oP, which is illuminated from below by the light projected from the light source LS moving below the original platen at the first moving speed V, is reflected from the reflecting mirror M1. The light is applied to the line image sensor LIS via the optical path of light M2→reflected light M3→imaging lens L→line image sensor LIS, and the image of the document is read by the line image sensor LIS.

(Problem to be solved by the invention) A reading position in an image to be read,
A moving optical system that is configured to maintain a constant distance from a line image sensor that is fixedly provided at a specific position performs sub-scanning of the original image, and also uses the moving optical system described above. The line image sensor LIS is configured to perform main scanning by the line image sensor LIS on which the image of the document is formed by the system, thereby obtaining an image signal corresponding to the image of the document from the line image sensor LIS. 7 In the image reading device shown in FIG. 7, in order for the image of the fM document to be imaged on the line image sensor LIS by the imaging lens L, the optical path length a from the reading position of the original to the imaging lens L, and the The optical path length from the image lens L to the line image sensor LIS is between the focal length f of the imaging lens L.

It is well known that the relationship (1/a)+(1/b)=1/f-(A) must hold true.

By the way, the size of the image being read is
For example, even when changing from a large state such as QIXQl in Fig. 7 to a small state such as f12XQ2 in Fig. 7, the effective reading width (the sensor in the direction perpendicular to the page In order to form images of the same size on the line image sensor LIS having a length of , it is necessary to change the magnification b/a in the imaging optical system.

In the case of the above example, the image forming optical system converts the image (
When a magnification change operation such as Ql/Q2) is performed using the same imaging lens L, conventionally, a predetermined magnification b/a can be obtained, and the above equation (A) can be For example, the position of the imaging lens L shown in the solid line illustrated in FIG. While displacing the mirror M to the position Lα shown by the dotted line,
The position of the reflecting mirror member MA consisting of 2°M3 is M in Fig. 7.
Although the magnification was displaced from the position A to the position MAα, the range of magnification that can be realized in the conventional image reading apparatus as described above is up to b/a of about 2.

However, when using a line image sensor LIS with an effective reading width of 30 to 60 mm, for example, the width is 297 mm.
An image of the size of A row No. 3 in mm or a width of 210 m
Conventional image reading devices are capable of reading images as large as No. 4 in column A of a 35 mm film, and can also read images on 35 mm film in high definition. If an image reading device with a much larger magnification range than the other device is desired, the seventh
Since the conventional image reading device as illustrated in the figure cannot meet such demands, a solution has been sought.

(Means for Solving Problems a and It) The present invention includes a first reflective optical member that reflects light from an image to be read into a first optical path parallel to the surface of the image; The light emitted from the first reflective optical member is parallel to the first optical path described above.

and a second reflective optical member that reflects light traveling along a second optical path in a direction opposite to the traveling direction of the light emitted from the first reflective optical member; In an image reading device comprising a line image sensor installed at a distance apart, and an imaging lens that forms an image of the image information to be read on the line image sensor. The image reading device may be configured as an enlarging optical system by positioning the above-mentioned imaging lens in the above-described first optical path, or the above-described imaging lens may be arranged in line with a second reflective optical member.
The image reading device is located in a second optical path between the image sensor and the image reading device, and the image reading device is configured as a reduction optical system. A first reflective optical member for reflecting light onto a first optical path parallel to the surface is moved at a first moving speed in a direction parallel to the image surface, and the light traveling on the first optical path is reflected into the first optical path parallel to the surface. A second reflective optical member as described above that is parallel to the first optical path and that reflects light traveling along a second optical path in a direction opposite to the traveling direction of the light emitted from the first reflective optical member. The first reflective optical member is moved parallel to the image plane at a speed of 172, which is the first moving speed, in the same direction of movement as the first reflective optical member, and from the image reading position. In an image reading device in which line image sensors are installed at positions separated by a predetermined distance, when one image reading device is used as a magnifying optical system, the imaging lens is the first reflective optical member described above. is moved integrally with the first reflective optical member in a first optical path between the first reflective optical member and the second reflective optical member while maintaining a predetermined constant value for Further, when the image reading device is used as a reduction optical system, the above-mentioned imaging lens is connected to the line image sensor in the second optical path between the second reflective optical member and the line image sensor. an image reading device installed at a predetermined distance from the image reading device; and a first reflective optical member that reflects light from the image to be read into a first optical path parallel to the surface of the image. The light emitted from the first reflective optical member is directed to a second optical path parallel to the first optical path and opposite to the traveling direction of the light emitted from the first reflective optical member. a second reflective optical member that reflects the light as it travels along the optical path; a line image sensor installed at a position separated by a predetermined distance from the image reading position; and the image to be read. It includes an imaging lens for forming information onto the line image sensor, and the imaging lens is connected to the first reflective optical member between the first reflective optical member and the second reflective optical member. The image reading device may be configured as a magnifying optical system by placing it in the optical path, or the imaging lens may be placed in the second optical path between the second reflective optical member and the line image sensor. In the image reading device configured as a reduction optical system, the first reflective optical member is replaced with the first reflective optical member.
At the same time, the light-transmissive original is moved in a plane perpendicular to the direction of light travel in the first optical path, and the light that has passed through the light-transmissive original is transferred to the second optical path.
Provided is an image reading device in which light is incident on a reflective optical member.

(Operation) Light emitted from a first reflective optical member that reflects light from an image to be read into a first optical path parallel to the plane of the image is made to enter a second reflective optical member.

parallel to the first optical path from the second reflective optical member,
and emitting light traveling in a second optical path in the opposite direction to the traveling direction of the light in the first optical path, and separating the light by a predetermined distance from the image reading position by an imaging lens. An image is formed on a line image sensor installed at the position to form an image reading device with a reduction optical system.

Further, the imaging lens installed in the second optical path described above is moved to be installed in the first optical path, thereby constructing an image reading device equipped with a magnifying optical system with a large magnification ratio.

(Example) Hereinafter, specific contents of the image reading device of the present invention will be described in detail with reference to the accompanying drawings. 1 and 2 are side views for explaining the configuration principle and operating principle of the image reading device of the present invention, and FIGS. 3 to 6 are respectively different embodiments of the image reading device of the present invention. FIG. 2 is a side view showing a schematic configuration of an example.

First, with reference to FIGS. 1 and 2, the principle of construction and operation of the image reading apparatus of the present invention will be explained. 1st
Figures 1 and 2 show a first reflective optical member (reflector Ml) that reflects light from an image to be read into a first optical path parallel to the surface of the image, and a reflector M1 as described above. A second reflective optical member (reflective optical member) that reflects the emitted light as light traveling along a second optical path parallel to the first optical path and opposite to the traveling direction of the emitted light from the reflective fiM1. @M2. M3), a line image sensor LIS installed at a predetermined distance from the image reading position, and a line image sensor LIS that contains the image information to be read.・Sensor L
1 is a side view showing a schematic configuration of an image reading device of the present invention, which includes an imaging lens L that forms an image on an IS.

FIG. 1 shows a configuration in which the imaging lens L is positioned in the first optical path so that the image reading device of the present invention is equipped with a reduction optical system. Further, FIG. 2 shows the configuration when the imaging lens L is positioned in the second optical path so that the image reading device of the present invention is configured with an enlarging optical system. There is.

That is, in the image reading device of the present invention, the imaging lens L described above is movable in the direction of the thick arrow shown in FIGS. By setting it at a predetermined position in the first optical path, it can be configured as an image reading device equipped with a reduction optical system, or by setting it at a predetermined position in the first optical path, it can be configured as an image reading device equipped with an enlargement optical system. It may be configured as an image reading device.

The image reading device shown in FIG. 1 and FIG. Although the image reading device of the present invention is shown as using a moving optical system configured to keep the distance constant, the image reading device of the present invention is also shown in the embodiments described below. As shown in FIG. 3, the present invention may be implemented in a configuration in which the moving optical system as described above is not used.

In the image reading apparatus shown in FIGS. 1 and 2, OP is an original plate made of, for example, a glass plate, LS is a light source, Ml, M2 . M3 is a reflecting mirror, L is an imaging lens, LIS is a line image sensor, and a document to be read is placed on the document table OP.

When the image reading device performs an image reading operation, the light source LS and the reflecting mirror M1 integrally move below the document table ○P in parallel with the document table OP at a first speed V, and Mirror M2. M3 is 1/ of the first moving speed V mentioned above.
It moves below the document table OP parallel to the document table ○P at a moving speed of V/2 of The distance between the sensor and the line image sensor is always kept constant.

When the imaging lens L is set at a predetermined position in the second optical path as in the image reading device shown in FIG. (or from the 0' point in the image reading section to the line image sensor L)
The optical path to point t of the IS) is 0 at the image reading section.
point → point p on reflecting mirror M1 → point q on reflection@M2 → point r on reflecting mirror M3 → point S on imaging lens L → point t on line image sensor LIS (or 0' on image reading section) point → p' point on reflecting mirror Ml; point q' on reflecting mirror M2 → point r' on reflection @ M3 → point S of imaging lens L → point t of line image sensor LIS). In this state, an image reading device is configured that includes a reduction optical system in which the reflected light from the image of the original is focused on the line image sensor LIS by the imaging lens L in a reduced state at a predetermined reduction ratio. As shown in FIG.
The length of the optical path from the point to the point t of the line image sensor LIS and the focal length f of the imaging lens L is determined by the equation (A) above, that is, (1/a) + (1/b )=1/f
- The relationship (A) holds, and the optical path lengths a and b described above are
The above-mentioned optical path lengths a and b are determined in relation to the focal length f of the imaging lens L so that the magnification b/a determined by b/a is a predetermined reduction ratio.

Furthermore, when the imaging lens L is set at a predetermined position in the first optical path as in the image reading device shown in FIG.・The optical path to point t of the image sensor LIS (or the optical path from point 02 in the image reading section to point t of the line image sensor LIS) is from point Q in the image reading section to the reflecting mirror. Point p in M1 → Point S on imaging lens L → Point q on reflecting mirror M2 → Point r on reflecting mirror M3 → Point t on line image sensor LIS (or point 0' on image reading section → Reflection @ In this state, An image reading device includes an enlarging optical system in which reflected light of an image of an original is focused on a line image sensor LIS by an imaging lens L (or L') in a state in which it is enlarged at a predetermined enlargement ratio. From the document reading position 0 point (or 0' point) to the imaging lens L (or L
The optical path length a from the point S (or point S') of the imaging lens [7 (or L') to the point t of the line image sensor S If the optical path is lengthened.

Between the focal length f of the imaging lens L, the above-mentioned formula (A),
That is, the relationship (1/a) + (1/b) = 1/f - (A) holds, and the magnification b is determined by the optical path lengths a and b described above.
The above-mentioned optical path lengths a and b are determined in relation to the focal length f of the imaging lens L so that /a has a predetermined magnification ratio. In the image reading device equipped with the magnifying optical system shown in FIG. The optical path length a to point) is
The imaging lens L is moved at a speed V together with the reflection @Ml so that it always maintains a predetermined constant value even when the moving optical system moves.

As is clear from the explanation given with reference to FIGS. 1 and 2, in the image reading apparatus of the present invention, an imaging lens L having a focal length f is connected to a reflecting mirror M3 and a line image sensor L I The optical path length a from the document reading position to the imaging lens L when installed in the optical path (second optical path) to S to form a reduction optical system, and the line image sensor from the imaging lens L If the optical path to LIS is long, an imaging lens L with a focal length f is positioned in the second optical path between the reflected light Ml and the reflected light M2, and the image reading device is configured as an enlarging optical system. , the document reading position when the image reading device forms a reduction optical system by positioning the above-mentioned imaging lens in the second optical path between the second reflective optical member and the line image sensor. Since the optical path length a from the imaging lens L to the line image sensor LIS and the optical path length from the imaging lens L to the line image sensor LIS can be switched and changed over a wide range, a reduction optical system that exhibits a predetermined reduction ratio can be used. a first image reading device as shown in the figure;
The image reading device as shown in the figure is connected to the same imaging lens L.
can be constructed by a simple means of moving the image between the second optical path and the first optical path, and the above-mentioned mode of movement allows the image formation while placed in the first optical path. The entrance side surface (output side surface) of the lens L is used as the exit side surface (incidence side surface) of the imaging lens L installed in the second optical path, so that it is not included in the reduction optical system. There is also an advantage that the imaging lens L is used under similar usage conditions, both when used in the magnifying optical system and when used in the magnifying optical system.

In the image capturing device shown in FIGS. 1 and 2, the original platen oP
The document placed above is sub-scanned with light from the light source LS, and the light reflected from the document is sent to the line image sensor LIS.
The original is scanned by main scanning of the line image sensor LIS, but in each of the embodiments shown in FIGS. This is an example in which the detection is performed using light transmitted through the original.

First of all, FIG. 3 shows that when the imaging lens L is set at a predetermined position in the first optical path to constitute an enlarging optical system as in the image reading device shown in FIG. A transmissive recorded recording medium OL is fixedly placed on the document table OP, and a light source unit LSA moves in synchronization with the moving optical system at the same moving speed V as that of the moving optical system.
The reading operation is performed by irradiating light onto the above-mentioned transmissive type recorded recording medium OL and making the light transmitted through the transmissive type recorded recording medium OL enter the reflecting mirror M1 in the moving optical system. This is an example configured as follows.

In addition, in the above-mentioned embodiment, the light source part L moves in synchronization with the moving optical system at the same moving speed V as the moving optical system.
Light is irradiated from the SA to the transmissive recorded recording medium OL, but a fixed light source that can illuminate the transmissive recorded recording medium OL with light with uniform intensity over the entire reading range is used to illuminate the transmissive recorded recording medium OL over a wide area. Light may be irradiated and the light transmitted through the transmissive recorded recording medium OL may be applied to the reflection fiM1 of the moving optical system.

Next, each of the embodiments shown in FIG. 4 to FIG.
When a magnifying optical system is configured by setting the imaging lens L at a predetermined position in the first optical path as in the image reading device shown in the figure, a transmission-type recorded recording medium can be used without moving the optical system. This figure shows an example of a configuration in which an image is read by moving the OL for sub-scanning. In this way, when the transmissive recorded recording medium OL is moved for sub-scanning and the reflecting mirrors M1 to M3 and the imaging lens L are kept stationary, the image shown in FIGS. Compared to the case where a common moving optical system is used for the reduction optical system and the enlargement optical system to perform sub-scanning as in the embodiment, it is easier to improve the accuracy of sub-scanning. It becomes easy to read an image in high definition from a recording medium on which a shape has been recorded.

First, in the embodiment shown in FIG. 4, the light from the stationary light source part LSA is transmitted through the document table OP and then incident on the reflecting mirror M1, and the light is reflected by the document table OP and #! This figure shows an example of a configuration in which a transmissive recorded recording medium OL is moved for sub-scanning between M1 and the image is read.

Further, in the embodiment shown in FIG. 5, the light from the stationary light source LSA is made to enter the reflecting mirror M1 without passing through the document table OP.
1 shows an example of a configuration in which an image is read by moving a transmissive recorded recording medium OL for sub-scanning between 1 and 1. In the embodiment shown in the fifth diagram, as in the case of the embodiment shown in the fourth diagram described above, when the light from the stationary light source section LSA is transmitted through the manuscript table OP, the problem may occur due to the existence of the manuscript table OP. Problem 5: For example, there is an advantage of being able to eliminate light loss, the influence of dust, etc.

Next, in the embodiment shown in FIG. 6, the light source LS used in the image reading apparatus shown in the embodiments shown in FIGS. The reflector M1 is used as a light source LS so that it can also be used as a light source.
A configuration in which the image is read by removing the light from the light source LS from the optical path and moving the transmissive recorded recording medium OL into the path of the light from the light source LS for sub-scanning. This is an example. The embodiment shown in FIG. 6 shows a configuration example in which the reflecting mirror M1 is rotatable.

(Effects of the Invention) As is clear from the detailed explanation above, the image reading device of the present invention reflects light from an image to be read into a first optical path parallel to the surface of the image. 1st
and a direction in which the light emitted from the first reflective optical member is parallel to the first optical path and opposite to the traveling direction of the light emitted from the first reflective optical member. a second reflective optical member that reflects light traveling along a second optical path; a line image sensor installed at a predetermined distance from the eight image reading positions; In an image reading device including an imaging lens that forms an image of target image information on the line image sensor, the imaging lens is positioned in the first optical path and the image is read. The image reading device can be configured as a magnifying optical system, or the image reading device can be configured as a reducing optical system by positioning the above-mentioned imaging lens in the second optical path between the second reflective optical member and the line image sensor. Since the image reading device is configured as a
When installed in the optical path to form a reduction optical system, the optical path length a from the document reading position to the imaging lens L and the optical path length from the imaging lens L to the line image sensor LIS are: An imaging lens L having a focal length f may be positioned in the first optical path to configure the image reading device as an enlarging optical system, or the imaging lens described above may be combined with a second reflective optical member and a line image sensor. The optical path length a from the document reading position to the imaging lens L when the image reading device is positioned in the second optical path between Since the length of the optical path up to the image sensor LIS can be changed over a wide range, the image reading device is equipped with a reduction optical system that provides a predetermined reduction ratio, and an enlargement optical system that provides a predetermined large enlargement ratio. The image reading device can be configured by a simple means of moving the same imaging lens L between the second optical path and the first optical path. The incident side surface (output side surface) of the imaging lens L installed in the first optical path is the exit side surface (incidence side surface) of the imaging lens L installed in the second optical path. Therefore, the imaging lens L is used in the same manner whether it is used in a reduction optical system or an enlargement optical system. Benefits can also be obtained5.
According to the present invention, the conventional problems as described above can be easily solved.

[Brief explanation of drawings]

1 and 2 are side views for explaining the configuration principle and operating principle of the image reading device of the present invention. 3 to 6 are side views showing schematic configurations of different embodiments of the image reading apparatus of the present invention, and FIG. 7 is a side view showing an example of the configuration of a conventional image reading apparatus. OP...Original table, LS...Light source, Ml, M2. M
3... Reflector, L, L'... Imaging lens, LIS...
・Line image sensor, MA, MA', MAα
...Reflector member, LSA...Light source part, OL...Transmission type recorded recording S medium,

Claims (1)

[Claims] 1. A first reflective optical member that reflects light from an image to be read into a first optical path parallel to the surface of the image, and a first reflective optical member as described above. a second optical path that is parallel to the first optical path and is reflected as light traveling along a second optical path in a direction opposite to the traveling direction of the light emitted from the first reflective optical member; a reflective optical member, a line image sensor installed at a predetermined distance from the image reading position, and a line image sensor that captures the image information to be read.
In an image reading device including an imaging lens for forming an image on a sensor, the imaging lens may be positioned in the first optical path to configure the image reading device as an enlarging optical system; an image reading device 2 in which the image reading device is configured as a reduction optical system by positioning the image forming lens in the second optical path between the second reflective optical member and the line image sensor; The light from the image being read is directed to the first parallel to the image plane.
The first reflective optical member to be reflected in the optical path is moved at a first moving speed in a direction parallel to the image plane, and the light traveling in the first optical path is reflected in a direction parallel to the first optical path. , and the second reflective optical member that reflects the light traveling along the second optical path in the opposite direction to the traveling direction of the emitted light from the first reflective optical member is moved at the first moving speed described above. The first reflective optical member is moved parallel to the image plane at a speed of 1/2 in the same direction as that of the first reflective optical member, and a predetermined distance from the image reading position. In an image reading device in which line image sensors are installed at separate positions, when the image reading device is used as a magnifying optical system, the imaging lens is placed in a predetermined position relative to the first reflective optical member. The first reflective optical member and the second reflective optical member are held at a constant value.
When the image reading device is used as a reduction optical system, the above-described imaging lens is moved integrally with the first reflective optical member in the first optical path between the reflective optical member and the reflective optical member. An image reading device 3 is installed in a second optical path between the second reflective optical member and the line image sensor at a predetermined distance from the line image sensor. a first reflective optical member that reflects light from an image on a first optical path parallel to the plane of the image; , and a second reflective optical member that reflects light traveling along a second optical path in a direction opposite to the traveling direction of the light emitted from the first reflective optical member, and It is equipped with line image sensors installed at positions separated by a distance of The image reading device may be constructed as an enlarging optical system by positioning the imaging lens in the first optical path between the first reflective optical member and the second reflective optical member, or the imaging lens described above may be configured as an enlarging optical system. In the image reading device, the lens is located in the second optical path between the second reflective optical member and the line image sensor, and the image reading device is configured as a reduction optical system. The first reflective optical member is retracted from the first optical path, and the light-transmissive original is advanced in a plane perpendicular to the direction of light propagation in the first optical path, so that the light-transmissive original is transmitted through the first optical path. An image reading device in which the reflected light is incident on a second reflective optical member.