JPH06311314A - Image reader - Google Patents

Abstract

(57) [Summary] [Purpose] In an image reading apparatus for reading an image on a document from the top, regardless of the thickness of the document, it is possible to always read neatly without defocus. A document table 11 on which a document 10 is set with the reading surface s facing upward, a light source 15 provided opposite to the document table 11 to illuminate the reading surface s, and a reflected light from the reading surface s are transmitted through an optical system 13. Then, the reading unit 12 that forms an image at the position of the CCD sensor 14 and reads the image by using the reading unit 12 and the measuring unit 18 that measures the height from the document table 11 to a specific position on the reading surface s, and thereby CC
It comprises an adjusting means 19 for moving and adjusting the optical system 13 so that an image is formed at the position of the D sensor 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading device such as a scanner, a facsimile, a transfer machine and a copying machine.

[0002]

2. Description of the Related Art Generally, an image reading apparatus of this type is provided with a document table and an openable / closable pressing plate which covers the document table on the apparatus body. When reading a document, open the holding plate, place the document on the platen with the reading surface facing down, close the holding plate again to hold the document, and read the information on the document from the bottom with the optical system. Was there.

However, in such an image reading apparatus,
Since the information on the original is read from the bottom, there is the inconvenience of repeating the opening and closing of the holding plate and the series of operations with the reading surface of the original facing down, and there is the inconvenience that the reading surface is hidden and the reading surface cannot be checked. It was

Therefore, in this type of image reading apparatus,
For example, as shown in FIG. 7, the original 1 is set on the original table 2 with the reading surface upward, and the reflected light is transmitted through the optical system 4 into the CCD sensor 5 by applying light from the light source 3. , That C
There is a configuration in which the image is read by the CD sensor 5.

[0005]

However, in such a conventional image reading apparatus, in the case of a thin sheet-shaped original 1 and a thick book-shaped original as shown, for example, from the original table 2 to the reading surface of the original. Since the heights are different, there is a problem in that a book-shaped document is out of focus and the image on the reading surface cannot be read cleanly.

Therefore, an object of the present invention is to make it possible to always read neatly regardless of the thickness of a document without causing a focus shift.

[0007]

Therefore, according to the first aspect of the present invention, the original 10 is set on the original table 11 with the reading surface facing upward and the light source 1 is used, for example, as in the following illustrated embodiment.
The light from 5 is applied, and the reflected light is transmitted through the optical system 13 to C
In the image reading device which is placed in the CD sensor 14 and reads the image by the CCD sensor 14, the distance measuring means 18 for measuring the distance to the specific position on the reading surface of the original 10.
And the optical system 1 based on the measurement result of the distance measuring means 18.
3 is provided with an adjusting means 19 for moving.

According to a second aspect of the present invention, the image reading apparatus according to the first aspect is provided with a plurality of the distance measuring means 18, as in the following illustrated embodiment.

According to a third aspect of the present invention, the distance measuring means 18 is movable in the image reading apparatus according to the first or second aspect, for example, as in the following illustrated embodiment. And

[0010]

According to the present invention, when the information on the original is read, the original 10 is set on the original table 11 with the reading surface facing upward, and from the original table 11 to a specific position B on the reading surface of the original 10. The height is measured by the distance measuring unit 18, and the optical system 13 is moved and adjusted by the adjusting unit 19 based on the measurement result.

According to the second aspect, the distances to the plurality of specific positions I and B on the reading surface of the original 10 are measured by the separate distance measuring means 18.

According to the third aspect, the distance measuring means 18
Is moved to measure the distance to the reading surface of the document 10.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an image reading apparatus according to an embodiment of the present invention, showing a schematic configuration of a main part thereof.

In this image reading apparatus, a document table 11 on which a document 10 is placed is arranged below, and a reading section 12 is arranged above the document table 11 with a constant space A therebetween. The reading unit 12 includes an optical system 13 having a zoom mechanism and a CCD sensor 14. The optical system 13 has a plurality of lenses 13 a and is provided so as to face the document table 11. The CCD sensor 14 is arranged above the optical system 13 in the figure. A light source 15 is arranged on the left side of the reading unit 12 in the figure. The light source 15 is supported by a spiral arm 16 which can move freely, as shown in FIG.

Further, on the right side of the reading unit 12 in the drawing, distance measuring means 18 for measuring the distance to a specific position B on the reading surface of the original 10 is provided as shown in the figure. The distance measuring unit 18 uses, for example, a reflection type photo sensor / ultrasonic sensor, and is electrically connected to the adjusting unit 19. The adjusting means 19 moves the optical system 13 based on the measurement result of the distance measuring means 18, and is electrically connected to the driving means of the optical system 13.

In the case of a thick book-shaped original 10, the reading page is opened and the original 10 is set on the original table 11 with the reading surface s facing up, as shown in the figure. Then, the light source 15 is moved so that no shadow appears on the reading surface s. At this time, since the light from the light source 15 is applied from directly above the document 10, for example, as shown in FIG. 4, when the light from the light source 15 is applied from the side, the shadow B formed in the binding margin portion of the document 10 can be eliminated. . Then, the distance to the specific position B on the reading surface s is measured by the distance measuring means 18. Based on the measurement result, the adjusting means 19 moves and adjusts the optical system 13. Then, the light from the light source 15 is applied to the reading surface s, and the reflected light is transmitted through the optical system 13 to the CCD sensor 14.
The CCD sensor 14 reads an image on the reading surface s.

On the other hand, as shown in FIG. 3, when the reading surface s of the thin sheet-shaped document 10 is read, the document 10 is set on the document table 11. Then, the light source 15 is moved so that the light from the light source 15 is applied from directly above the original 10. Then, the distance to the specific position B on the reading surface s is measured by the distance measuring means 18. Based on the measurement result, the adjusting means 19 moves and adjusts the optical system 13. Then, the light from the light source 15 is applied to the reading surface s, and the reflected light is reflected by the optical system 13.
Through the CCD sensor 14 to form an image, and the CCD sensor 14 reads the image on the reading surface s.

In the image reading apparatus of the illustrated embodiment, the distance to the specific position B on the reading surface s of the original 10 is measured by one distance measuring means 18. However, the distance to the specific position on the reading surface s of the original 10 is determined by the plurality of distance measuring means 1.
The measurement may be performed at 8. For example, as shown in FIG. 5, the distances to a plurality of positions I and R on the reading surface s are independently measured by the respective distance measuring units 18 and 18.

Further, in all the illustrated embodiments, the distance measuring means 18 is fixed. However, although not shown, the distance measuring means may be movable.

By the way, as shown in FIG. 1, in the case of the book-shaped original 10, the central portion becomes a curved surface when opened,
If it is read as it is, the image may be distorted and read. Therefore, the distance to the specific position a on the reading surface s measured by the distance measuring unit 18 and the document 1 stored in advance
The relationship between the curved surface of the reading surface of 0 and the height may be compared, and the read information may be processed and output so that the curved surface of the reading surface is approximately a flat surface.

For example, the distance measuring means 18 for each book size
What kind of curved surface the reading surface s has according to the measurement result is stored. Then, as shown in FIG. 6, only by inputting the book size z, the shape of the reading surface s is obtained from the measurement result of the distance measuring means 18, and as shown in the figure, the portion a and the portion b are separated by the position a. In addition, the portion a can be expanded as a 'and the portion b can be expanded as b'for output. In this way, the read information can be output in a state that is easy to read.

[0022]

Therefore, according to the present invention, when the information on the original is read, the height from the original table to the reading surface of the original is measured by the distance measuring means, and the optical system is adjusted by the adjusting means based on the measurement result. Is adjusted so that an image can always be accurately formed at the CCD sensor position. Therefore, for example, a thin sheet original or a thick book original can be accurately read and a good image can be obtained without defocusing.

According to the second aspect of the present invention, since the height from the document table is measured at a plurality of positions on the reading surface and the optical system is moved and adjusted, the entire reading surface can be read better. .

According to the third aspect of the invention, the height from the platen to the reading surface of the original is measured more finely along the moving direction of the distance measuring means, so that the entire reading surface can be read better. You can

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a main part of an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a support structure of the light source.

FIG. 3 is an explanatory diagram when a sheet-shaped document is read by the image reading apparatus.

FIG. 4 is an explanatory diagram showing that a shadow is generated when light from a light source is applied from the side.

FIG. 5 is a schematic view of an image reading apparatus including two distance measuring means.

FIG. 6 is an explanatory diagram illustrating expansion and output of read information.

FIG. 7 is an external perspective view showing a conventional image reading apparatus.

[Explanation of symbols]

 10 Reading Device Main Body 13 Optical System 14 CCD Sensor 15 Light Source 18 Distance Measuring Means 19 Adjusting Means

Claims (3)

[Claims] 1. An image in which an original is set on an original table with its reading surface facing up, light from a light source is applied, and the reflected light is transmitted through an optical system into a CCD sensor, and the image is read by the CCD sensor. An image reading apparatus, comprising: a reading device, a distance measuring unit that measures a distance to a specific position on the reading surface of the document, and an adjusting unit that moves the optical system based on a measurement result of the distance measuring unit. . 2. The image reading apparatus according to claim 1, comprising a plurality of the distance measuring means. 3. The image reading apparatus according to claim 1, wherein the distance measuring unit is movable.