JPH0355961A - Picture reader - Google Patents

Abstract

PURPOSE:To form a picture reader with high magnification by moving a 2nd original platen with an original being a read object set thereon in a direction traversing an optical path between a 2nd reflecting mirror and a 3rd reflecting mirror. CONSTITUTION:A moving optical system comprising a light source and 1st-3rd reflecting mirrors M1-M3 is fixed to a predetermined position in the vicinity of the outside of one end in a 1st original platen OP1, the position of an image forming lens L and a line image sensor LIS is moved to a position in which a picture of an original moved in a direction traversing the optical path between a 2nd reflecting mirror and a 3rd reflecting mirror is formed to the line image sensor LIS as an image with a prescribed magnification by an image forming lens L. Then after an original being an object of read is set to the 2nd original platen OP2, the 2nd original platen OP2 is moved in a direction traversing the optical path between the 2nd reflecting mirror and the 3rd reflecting mirror.

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) FIG. 3 shows a first reflecting mirror M1 that reflects light from an image of a document to be read into a second optical path parallel to the surface of the document at a first moving speed V. The light traveling in the first optical path is moved in a direction parallel to the surface of the original, and the light traveling in the first optical path is parallel to the first optical path and in the traveling direction of the light emitted from the first reflection glM1. in the opposite direction
The second and third reflecting mirrors M2 and M3, which reflect the optical path as traveling light, are moved parallel to the surface of the document at a speed V/2, which is 1/2 of the first moving speed V. A reflection! !
The image is made to move in the same direction as the movement direction of M1, and the light traveling in the second optical path is imaged on the line image sensor LIS by the imaging lens L. FIG. 2 is a side view showing a schematic configuration of a reading device. In the image reading apparatus shown in FIG. 3, OP is an original plate made of, for example, a glass plate. LS is the light source, M1 is the first reflecting mirror, M2 is the second
, M3 is the third reflecting mirror, L is the imaging lens, LI
S is a line image sensor, and when the image reading device performs a reading operation, the above-mentioned first reflecting mirror M1 moves at a first movement speed V in a direction parallel to the surface of the document, and The second and third reflecting mirrors M2 and M3 integrally move parallel to the surface of the document at a speed V/2, which is 1/2 of the first moving speed V. The light source LS and the first reflection fiM1 are integrated, and the light source LS and the first reflection fiM1 are configured to move in the same direction as the direction of the movement.
K Draw a solid line parallel to the manuscript table OP at a moving speed of V within the range from the part indicated by point O to the part indicated by point 0' in Fig. 3 below the manuscript table OP. Move from the Ml position shown in the figure to the Ml' position shown by the dotted line. As mentioned above, the light source LS and the first reflecting mirror M1 are integrated and the document table OP is moved within the range from the part indicated by point O to the part indicated by point Ol in FIG. When moving at a first moving speed V in parallel with
The reflection @M2, M3 is 1/ of the first moving speed V mentioned above.
2 at a moving speed of V/2, the aS table OP is moved below the document table OP in parallel with the document table OP from the positions M2 and M3 shown by the solid line in the figure to the positions M2' and M3' shown by the dotted line. The distance between the reading position in the target image and the line image sensor installed at a specific position is always kept constant. Then, the reflected light from the original on the original platen OP illuminated from below by the light projected from the light @LS moving below the H original platen at the first moving speed V is reflected @ Ml → reflection fiM2 → reflection tItM3 → imaging lens L
→The image of the original is given to the line image sensor LIS through the optical path of the 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) The reading position in the image to be read,
A moving optical system configured to always maintain a constant distance from the line image sensor LIS provided at a specific position performs sub-scanning of the original image, and the above-mentioned moving optical system By performing main scanning with the line image sensor LIS on which the original image is formed, an image signal corresponding to the image of the JJK manuscript is obtained from the line image sensor L'IS. In the image reading device shown in FIG. 3, in order for the image of the document to be focused on the line image sensor LIS by the imaging lens L, the optical path length a( Distance from point o → point p → point q → point r → point S or 02 point → point p' → q'
The distance 11) from point → point r' → point S, and the optical path length b from imaging lens L to line image sensor LIS (point s → t
point distance) and the focal length Mf of the imaging lens L, (1/a)+(1/b)=l/f・
= It is well known that the relationship (A) must hold. now. For example, an imaging lens L with a focal length f of 75 mm and a line image lens L with an effective reading width of 60 mm, for example.
For example, the width of row A 3@ is 297 m by the image reading device shown in FIG.
The width of the original is 297 m in order to scan the image of the original (with a length of 410 mm).
The optical path length a from the document reading position in the image reading device to the imaging lens L when the reading operation is performed such that m is the effective reading width of 60 mm in the line image sensor LIS, and the imaging The optical path length b from the lens L to the line image sensor LIS is approximately 446 mm. b is approximately 90 mm, and the magnification b/a in this case is 60/297. In the above-mentioned example, the original placed on the original platen OP in the copy scanning device shown in FIG. This is for the case where the reading operation is performed by moving the section corresponding to the section from 0 point to 0' point in the middle, and the optical system is used when the width of the document placed on the document table OP is 297 mm. , the length of the document in the width direction is 297 mm.
Effective reading width of image sensor LIS 60mm
Line image sensor LIS as length matching
For example, if the document to be placed on the document table OP of this image reading device and read is a small photographic film,
The photographic film original has the above magnification b/a = 6
Since it is to be read by the line image sensor LIS in a reduced state of 0 / 2 9 7, the line image sensor LIS will have only a part of its effective reading length used for reading. Therefore, as a matter of course, the image signal obtained from the line image sensor LIS by reading is of low resolution.
By the way, since a large amount of information is recorded on a small photographic film, it is desirable to be able to obtain high-resolution image signals when reading the photographic film with an image reading device. Of course, in the above case, in order to obtain a high-resolution image signal, the original must be imaged on the line image sensor LIS via an optical system. In this case, an optical system may be used in which the optical image in the width direction of the document is formed within the effective reading width of the line image sensor LIS. Now, for example, an original placed on the original platen OP to be read by an image reading device is column A 3f! Suppose that the original has a width of 175 times the original size i (for example, 6x6 photographic film), and the original is scanned into a line image through the optical system used in the image reading device.・Sensor LI
If an optical system is used that can make the dimensions of the optical image in the width direction of the document match the effective reading width of the line image sensor LIS, 60 mm, when the image is formed on S. , this optical system has a magnification of 5 times that of the optical system used to read the documents in the A column 3@ described above, but the imaging lens L used in the optical system described above has a magnification of 5 times.
As in the case of the above example, the focal length f is 75 m.
m, the optical path length a from the document reading position to the imaging lens L, and the line length from the imaging lens L.
If the optical path length b to the image sensor LIS is set to approximately 150 mm, then (1/a)
The relationship +(1/b)=1/f-(A) is established, and the image of the document is converted into a line image by the imaging lens L.
The image can be formed on the image sensor LIS. However, in an image reading device using a moving optical system as already described with reference to FIG. Optical path length a from the reading position of the original to the imaging lens L (point o → point p → point q → point r → s Distance of point n or 0" point → point p" → 9" point → r" The imaging lens L is located at such a position that the optical path length b from the imaging lens L to the line image sensor LIS (distance from the point s" to the point t") is obtained. When the line image sensor LIS is installed, the first to third reflecting mirrors M are used to read the original placed on the original platen OP.
When moving 1 to M3, the third reflection fiM3 may collide with the imaging lens L, as illustrated in FIG. 4, and it may become impossible to read the image. ．． That is, in FIG. 4, O → 0'' is the movement range of the first reflection tItMl performed on the original that has been blurred on the original platen OP, and the reading of the original placed on the original platen OP is as follows. In FIG. 4, the reflection is performed from the position of the first reflection fiM1 shown by the solid line to the position of the first reflection mirror M1'' shown by the dotted line. The image reading device shown in FIG. 4 has a magnification of b compared to the image reading device shown in FIG.
Since the position of the imaging lens L and the position of the line image sensor LIS are set to the right in the figure so that / a is large, it is difficult to place the document on the document table OP. During the image reading operation performed on the original document, as the reflecting mirror M1 is moved to the left in the figure at a moving speed V in the range from 0 to 0'', the second and third reflecting mirrors are moved to the left in the figure. M2, M3
When moving to the left in the figure at a moving speed of V/2, the moving second and third reflecting mirrors M2 and M3 reflect the second and third reflection fiM2'' and M3 indicated by dotted lines in the figure. At the position ``, the third reflection fiM3'' collides with the imaging lens L, causing a problem that it becomes impossible to read the image.
Since the above-mentioned problem occurs when the magnification b/a is increased, it is difficult to construct a high-magnification image reading device using the image reading device having the above-mentioned structure, and a solution to this problem has been sought. ．． (Means for solving problem a) The present invention provides image lines and
A first reflecting mirror that reflects light from the image sensor to form an image onto a first optical path parallel to the surface of the document is moved at a first moving speed in a direction parallel to the surface of the document, and The light traveling in the first optical path is reflected as light traveling in the second optical path parallel to the first optical path and in the opposite direction to the traveling direction of the light emitted from the first reflecting mirror. The second and third reflecting mirrors are moved parallel to the surface of the document at half the speed of the first moving speed and in the same direction of movement as the first reflecting mirror. In the image reading device in which the light traveling in the second optical path described above is imaged on the line image sensor by the imaging lens, the first to third reflecting mirrors described above are In a state where the movement is stopped, the original whose image is to be read is moved into the optical path between the second reflecting mirror and the third reflecting mirror so as to cross the optical path. An image reading device is provided which includes a moving means and means for forming an image of a document moved by the document moving means on a line image sensor using an imaging lens. (Function) Fixed document table ○Move below P1 to open the fixed document table OP.
I (first document table) A moving optical system consisting of a light source and first to third reflection fiM1 to M3 for scanning a document placed on a fixed document table ○P1 is placed on one end of a fixed document table ○P1. Fixedly position it at a predetermined position near the outside. The second original platen OP2, on which the original to be read is set, is moved into the optical path between the second reflecting mirror M2 and the third reflecting mirror M3 in a direction across the optical path. The light transmitted through the original set on the second original table OP2 is incident on the imaging lens L via the third reflection fiM3, and the imaging lens L directs the light to the line image sensor LI.
S and output an image signal from the line image sensor LIS. (Example) Hereinafter, specific details of the image reading device of the present invention will be described with reference to the accompanying drawings. 1 and 2 are side views showing a schematic structure of an image reading device according to the present invention. In the image reading apparatus of the present invention shown in FIGS. 1 and 2, ○P1 is a fixed document table (first document table) fixedly provided using, for example, a glass plate, LS is a light source, and M
l is the first reflecting mirror, M2 is the second reflecting mirror. M3 is the third reflecting mirror, L is the imaging lens, and LIS is the line image lens.
Further, WP is a reflecting member (for example, a standard white plate) for reflecting the light from the light source LS and applying it to the original set on the second original platen OP2. Figure 1 shows a document placed on the first document table OPI.
1i! (An image reading device used to explain the case where the moving optical system constituted by the LS and the first to third reflecting mirrors Ml-M3 is moved to read image information of a document. This is a side view of the first M manuscript table O.
When operating a document placed on the PI by moving a moving optical system constituted by a light source LS and first to third reflecting mirrors M1 to M3 to read the image information of the document, The image reading operation of the original placed on the first document table OPI is performed while the second document table OP2 is retracted out of the movement range of the moving optical system. When the image reading device shown in FIG. 1 performs a document reading operation, after placing the document to be read on the first document table OPI, the first reflection fiM1
The second and third reflecting mirrors M2 and M3 are integrally moved at a speed V of 1/2 of the first moving speed V. In step 2, the first reflection fiM1 is moved parallel to the surface of the original in the same direction as the movement direction of the first reflection fiM1 described above. The light source LS and the first reflection fiM1 work together to extend the area below the first document table OPI, for example from the part indicated by point O to the part indicated by point 01 in FIG. It is moved within the range parallel to the first document table OPI at a first moving speed V from the position M1 shown by the solid line to the position Ml' shown by the dotted line. As mentioned above, the light source LS and the first reflecting mirror M1 are integrated, and the document table is moved within the range from the part indicated by point O to the part indicated by point O' in FIG. OP
When the second and third reflecting mirrors M2 and M3 move at a first moving speed V from the position M1 shown by the solid line to the position Ml' shown by the dotted line in parallel with At a moving speed of 172 V/2, move below the first document table OPI and parallel to the first document table OPI as shown by the solid line M in the figure.
2. It moves from the position M3 to the positions M2' and M3' shown by dotted lines, thereby determining the reading position in the image that is the target of reading and the line image sensor LIS installed at a specific position. The distance between is always kept constant. Then, the lower part of the first document table OPI is moved at a first moving speed V.
The reflected light from the original on the first original platen OPI, which is illuminated from below by the light projected from the light source LS moving at
It is applied to the line image sensor LIS via the optical path from the imaging lens L to the line image sensor LIS, and is sent to the first document table O by the line image sensor LIS.
The image of the original placed on Pl is read. Next, when the image reading device shown in FIG. 2 performs a document reading operation, the light source and the first to third reflection fiM1
A moving optical system consisting of ~M3 is fixedly positioned at a predetermined position near the outside of one end of the first document table OPI, and an imaging lens L and a line image sensor LIS are The second reflection fiM2
and the third reflecting mirror M3 to a position where the image of the document is focused on the line image sensor LIS as an image with a predetermined magnification by the imaging lens L. and set it in that position. In this state, the light from the light source LS is reflected by the reflecting member (for example, a standard white plate) WP and given to the first reflecting mirror fiM1, and then the light from the second reflecting mirror M2 → the third reflecting mirror 11M.
3→imaging lens L→line image sensor LIS. After setting the original to be read on the second document table ○P2, the second document table OP2 is moved to the second reflecting mirror M2 and the third reflecting mirror M.
3, move it in the direction across the optical path. The light transmitted through the original set on the second original table is
The image is made incident on the imaging lens L through the reflecting mirror M3, and the imaging lens L forms an image on the line image sensor LIS, and the line image sensor LIS outputs an image signal. (Effects of the Invention) As is clear from the above detailed explanation, the image reading device of the present invention reflects light from an image of a document to be read onto a first optical path parallel to the surface of the document. The first reflecting mirror is moved at a first moving speed in a direction parallel to the surface of the document, and the light traveling in the first optical path is moved parallel to the optical path of the first optical path and The second and third reflecting mirrors, which reflect the light traveling along the second optical path in the opposite direction to the traveling direction of the light emitted from the first reflecting mirror, are moved at a speed that is 1/2 of the first moving speed. The mirror is moved parallel to the surface of the original in the same direction as the first reflecting mirror described above, and the light traveling along the second optical path is transformed into a line by an imaging lens. In an image reading device configured to form an image on an image sensor, when the movement of the first to third reflecting mirrors is stopped, there is a gap between the second reflecting mirror and the third reflecting mirror. A document moving means for moving the document whose image is to be read across the optical path is provided in the optical path, and the image of the document g moved by the document moving means is captured by an imaging lens. In the image reading apparatus of the present invention, the first document table ○P1
When a moving optical system is used to read a document set at
The imaging lens L and the line image sensor LIS are fixedly positioned at a predetermined position near the outside of one end of the document table OP1, and the positions of the imaging lens L and the line image sensor LIS are
The image of the document moved in the direction across the optical path between the reflecting mirror M2 and the third reflecting mirror M3 is formed on the line image sensor LIS by the imaging lens L as an image with a predetermined magnification. move it to a certain position and set it to that position,
The original to be read set on the second original table OP2 is moved in a direction across the optical path between the second reflecting mirror M2 and the third reflecting mirror fiM3. Since the conventional image reading device does not include the first and second reflecting mirrors in the optical path from the original to the imaging lens, conventional image reading devices do not include the first to second reflecting mirrors in the optical path from the original to the imaging lens.
Compared to a long lens including a third reflecting mirror, the distance from the original to the imaging lens is smaller, making it easier to read images at high magnification. The conventional problems described above can be easily solved.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 and 2 are side views showing a schematic structure of an image reading device of the present invention, FIG. 3 is a side view showing a schematic structure of a conventional image reading device, and FIG. 4 is a side view showing a schematic structure of a conventional image reading device. is a side view showing a schematic configuration of an image reading device for explaining the problem. OPI...Fixed original table (first original table). LS...
・Light source, M1...first reflecting mirror, M2...second reflecting mirror, M3...third reflecting mirror, L...imaging lens,
LIS...line image sensor, WP...reflective member (e.g. standard white plate),

Claims (1)

[Claims] A first reflecting mirror that reflects light from an image of a document to be read onto a first optical path parallel to the surface of the document.
The light traveling in the first optical path is parallel to the first optical path and is emitted from the first reflecting mirror. The second and third reflecting mirrors, which reflect light traveling in the second optical path in the opposite direction to the traveling direction of The first
The mirror is moved in the same direction as that of the reflecting mirror, and the light traveling along the second optical path is imaged on the line image sensor by the imaging lens. In the reading device, when the movement of the first to third reflecting mirrors is stopped, in the optical path between the second reflecting mirror and the third reflecting mirror,
Providing a document moving means for moving the document of the image to be read so as to cross the optical path,
an image reading device comprising means for forming an image of a document moved by the document moving means on a line image sensor using an imaging lens;