JPH0346615Y2 - - Google Patents

Description

[Detailed description of the invention] -Field of industrial application- This invention is a flatbed type, that is, a TV scan method that uses a one-dimensional image sensor for main scanning and sub-scanning by moving a carrier to scan an original placed in a fixed position. The present invention relates to an image input device for reading.

- Prior Art - FIG. 4 shows an example of a conventional flatbed type image input device, in which reading light L from a document placed on a document table 18 is reflected by a reflecting mirror 20 mounted on a carrier 19. After reflecting 90 degrees, the reflectors 22 and 23 mounted on the second carrier 21 reflect 180 degrees.
Imaging lens 2 mounted on a stationary member by turning the angle
4, the image is formed on the image sensor 25. Sub-scanning when reading a document is
This is done by moving the carrier 19, but in the structure shown in FIG. 4, the second carrier 21 is moved so that the optical path length from the document surface to the image sensor 25 does not change even if the carrier 19 moves. I am trying to move it in the same direction as 19 at 1/2 the speed. In FIG. 4, 26 is a housing of the apparatus, and 27 is a light source lamp mounted on the carrier 19 for illuminating the document reading section.

Another conventional example shown in FIG.
5 and an imaging lens 24 are mounted on a carrier 19 back to back with a reflecting mirror 20, and reading is performed by reflecting mirrors 28, 29, 30, and 31 each fixed at an angle of 90 degrees inside a housing 26. Light L
The image is rotated 360 degrees and formed into an image on the image sensor 25 via the imaging lens 24 (for example, Japanese Patent Laid-Open No. 58-57858).

Furthermore, as another structure, as shown in FIG. 6, a structure in which an imaging lens 24 and an image sensor 25 are mounted on a carrier 19 has been proposed. In the structure shown in FIG. 6, in order to obtain a predetermined optical path length from the document surface to the image sensor 25, two reflecting mirrors 32 and 33 are mounted on the carrier 19, and the reading light L is transferred to the reflecting mirror 32, 33. It is made to reflect repeatedly between 33 and 33 seconds.

-Problems to be solved by the invention- As mentioned above, in the conventional structure shown in Figure 4, it is necessary to move the second carrier 21 in the same direction as the carrier 19 at 1/2 the speed. An error in the relative speed between the carrier 21 and the carrier 19 appears as a double error in the optical path length, and if the second carrier 21 moves up and down, the reading light incident on the image sensor 25 will experience twice the axial deflection. wake up Therefore, the guide structure of the second carrier 21 and its drive system also require precision, which causes an increase in the cost of the device.

In the conventional structure shown in FIG. 5, the distance between the reflecting mirrors 28 and 31 must be larger than the movement stroke of the carrier 19, so the optical path length becomes longer than necessary, and a lens with a large focal length must be used. It will stop happening. If the focal length is large, the image will be dark and the reading speed will be reduced unless the lens has a large diameter, but large diameter lenses are very expensive, making it impossible to obtain an inexpensive and compact device. .

Further, in the conventional structure shown in FIG. 6, there is a restriction on the optical path length from the document surface to the image sensor 25, and it is necessary to use a lens with a short focal length as the imaging lens 24. Since the lens has a large angle of view, the magnification changes greatly if the original is lifted even slightly, causing problems such as distortion of the image due to bending of the original, and a reduction in the amount of light around the edges of the image.

This invention was made for the purpose of solving the problems of the conventional device described above and providing a cheaper and more compact image input device.

- Means for Solving the Problems - To explain using the reference numerals of the illustrated embodiment, the image input device of this invention has a carrier divided into an inner carrier 4 and an outer carrier 13. The inner carrier 4 is driven in the sub-scanning direction like a conventional carrier, and the outer carrier 13 is mounted so as to be freely movable along the guide 3 that guides the inner carrier 4.

The inner carrier 4 includes a reflecting mirror 6 that reflects the reading light L from the paper on the document table 2 in the sub-scanning direction.
, an image sensor 7 and an imaging lens 8 are mounted back to back. In the outer carrier 13,
A plurality of reflecting mirrors 9 to 12 are mounted to turn the light irradiated in the sub-scanning direction by 360 degrees by the reflecting mirror 6 of the inner carrier. The plurality of reflecting mirrors 9 to 12 mounted in this manner surround the inner carrier 4 with the optical path of the reflected light.

The reading light L reflected by the reflecting mirror 6 mounted on the inner carrier 4 is turned 360 degrees by the plurality of reflecting mirrors 9 to 12 of the outer carrier 13 and enters the inner carrier 4 from the opposite side, and forms the image. lens 8
The image is then formed on the image sensor 7.

- Effect - According to the above configuration, the length of the optical path from exiting the reflector 6 to being projected onto the image sensor 7 can be constant regardless of the moving position of the inner carrier 4, and can be Even when reading a long original, the optical path length can be set appropriately.
Furthermore, it is sufficient to drive only the inner carrier 4 when reading a document, and a drive system for the outer carrier 13 is not required.

-Example- Fig. 1 shows an embodiment of the present invention, in which 1 is a housing of the device, 2 is a document table provided on the top surface of the case 1, and 3 is a document table installed parallel to the document table 2. 4 is an inner carrier slidably attached to the guide rod 3; 5 is a light source lamp for document illumination; 6 is an inner carrier slidably attached to the guide rod 3;
7 is a one-dimensional image sensor, 8 is an imaging lens, and 9, 10, 11, and 12 are reflecting mirrors.

The reflectors 9 to 12 are mounted on an outer carrier 13 slidably mounted on the guide rod 3.
This outer carrier 13 is not provided with a drive mechanism. 14, 15 and 16, 17 are shock absorbers provided on the outer carrier 13;
collides with the shock absorber 14 or 15, causing the outer carrier 13 to move. Shock absorber 14,1
5 is a shock absorber 1 for mitigating the impact when the inner carrier 4 and the outer carrier 13 collide.
6 and 17 are provided to reduce the impact when the outer carrier 13 collides with the housing 1. 2 and 3 schematically show the position of the outer carrier 13 when the inner carrier 4 moves to the right end and left end in the drawings. The reflecting mirror 6 is mounted on the inner carrier 4 so as to reflect the reading light L from the original in the moving direction of the inner carrier 4 (in a direction parallel to the guide rod 3).
The image sensor 7 and the imaging lens 8 are the reflecting mirror 6
They are mounted back to back on the inner carrier 4. The inner carrier 4 travels along the guide rod 3 by a drive mechanism (not shown) to perform sub-scanning when reading a document.

The light reflected from the reflector 6 is transmitted to the reflector 9 or 1.
2 and turned 360 degrees, projected onto the inner carrier 4 from the opposite side, and formed into an image on the image sensor 7 via the imaging lens 8.

It is reasonable to use four reflecting mirrors 9 to 12 for turning the reading light L by 360 degrees, but it is not necessary to use four reflecting mirrors to turn the reading light L by 90 degrees.
It doesn't have to be one piece. For example, one reflective mirror between the reflective mirrors 9 and 12 may be configured to reflect light in a V-shape, or three reflective mirrors may be used.
The reflecting mirrors 9 to 12 are arranged on the movement axis of the reflecting mirror 6 and the image sensor 7, so that the light from the reflecting mirror 6 is projected onto the reflecting mirror 9, and the light from the reflecting mirror 12 is projected onto the image sensor. This is true if the light is projected onto the sensor 7 and the reflecting mirrors 9 to 12 are mounted so that their relative positions do not change.

If the reflecting mirrors 9 to 12 are mounted as described above, the optical path length of the reading light L will not change no matter how the inner carrier 4 and outer carrier 13 move on the guide rod 3.

In this way, if the reflecting mirrors 9 to 12 are provided on the outer carrier 13 which is slidable in the same direction as the inner carrier 4, the outer carrier 13 and the inner carrier 4
No matter how the lens moves along the guide rod 3, the length of the optical path from the reflector 6 to the image sensor 7 does not change. Therefore, there is no need to drive the outer carrier 13, and even if the outer carrier 13 moves up and down, left and right, or tilts, the position of the optical axis projected onto the image sensor 7 does not change. Since the guide structure does not need to be so precise, the device becomes inexpensive. Furthermore, even when reading a document long in the sub-scanning direction, the optical path length can be set appropriately, and an inexpensive lens with a standard focal length can be used.

- Effects of the invention - As described above, according to the invention, in a flatbed type image input device, changes in the optical path length due to carrier movement can be avoided with a simpler structure, and the optical path length from the document surface to the image sensor can be avoided. can be set to any length, a device with a simpler and more compact structure can be obtained, and an image input device that is small, lightweight, and inexpensive can be provided.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
3 and 3 are diagrams schematically showing the relationship between the moving position of the inner carrier and the moving position of the outer carrier in this embodiment. 4 to 6 are cross-sectional views showing conventional examples. In the figure, 2 is a document table, 3 is a guide rod, 4 is an inner carrier, 6 is a reflector, 7 is a one-dimensional image sensor, 8 is an imaging lens, 9 to 12 are reflectors,
13 is an outer carrier, and L is a reading light.

Claims (1)

[Claims for Utility Model Registration] In an image input device that reads character or graphic information on a two-dimensional plane using a TV scan method using main scanning of a one-dimensional image sensor and sub-scanning by moving a carrier, the carrier is an inner carrier 4. Outer carrier 13
The inner carrier 4 is driven in the sub-scanning direction, the outer carrier 13 is freely movable along the same guide 3 as the inner carrier 4, and the inner carrier 4 is A reflector 6 for reflecting the reading light L in the sub-scanning direction, an image sensor 7 and an imaging lens 8 are mounted back to back, and the outer carrier 13 has a mirror for turning the light irradiated in the sub-scanning direction 360 degrees. Multiple reflecting mirrors 9~
12 is mounted in such a manner that it surrounds the inner carrier 4 with the optical path of the reflected light, and the reading light L reflected by the reflector 6 mounted on the inner carrier 4 is transmitted to a plurality of reflectors 9 to 12 of the outer carrier 13. 12, and the image is formed on the image sensor 7 through the imaging lens 8 from the opposite side of the inner carrier 4.
Image input device.