JPH0488746A - Original reading device - Google Patents

Abstract

PURPOSE:To make the reader small by utilizing a correction data resulting from applying shading correction to an output of a photoelectric conversion section receiving a reflected light from a reference board on which a mark is marked. CONSTITUTION:A light from a light source 4 radiates to a reference board provided behind a read section 2 at original reading and a mark is marked on the reference board 3. A light radiating to the reference board 3 having the mark is reflected in the reference board 3 and made incident in a photoelectric conversion section 7. The conversion section 7 applies photoelectric conversion to the incident light and the resulting data is subject to interpolation processing and shading correction processing. When an original is carried, the mark marked to the reference board 3 is covered corresponding to the size of the original. Thus, the size of the original is recognized.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a document reading device.

[Prior Art] Document reading devices include image scanners and paper scanners, and document reading devices include so-called book-type devices that read a document placed on a document table, and a so-called book-type device that reads a document set on a document table, and a device that conveys a sheet document to a document reading unit and reads the document. There are so-called sheet-type devices that read originals conveyed to the department. In this sheet type, a document is conveyed to a document reading section, and when a document sensor or the like detects that the document has been conveyed to the document reading section, a light source projects light onto the document reading section. This reflected light from the original is introduced into the photoelectric conversion means, where it is photoelectrically converted and an image of the original is read. Further, in a sheet-type document reading device, the size of the document conveyed to the document reading section is detected by a document sensor or the like, and document reading processing is performed in accordance with the document size.

Therefore, sheet-type document reading devices are provided with a document sensor for detecting that a document has been conveyed to the document reading section, and a document sensor that detects the size of the document conveyed to the document reading section. A detection sensor is provided. In addition, as a photoelectric conversion means, C
CD (ChargeCouplecl Device
e) is used, and each light receiving element of this CCD is
Since the sensitivity is generally not uniform, shading correction is usually applied. In the above-mentioned sheet type document reading device, this shading correction is performed based on the reflected light from a reference plate provided in the document reading section, and the document reading device is equipped with a shading correction circuit for this shading. .

[Problem to be solved by the invention]

However, such conventional document reading devices have a configuration in which a document sensor detects that the document is conveyed to the document reading section, and a document size detection sensor detects the size of the document. Therefore, a document sensor for detecting that the document has been conveyed to the document reading section and a document size detection sensor for detecting the document size are required, which not only increases the size of the document reading device, but also increases the size of the document reading device. There was a problem of high cost.

[Purpose of the invention]

Therefore, the present invention provides a method in which a plurality of marks are provided on the reference plate in the width direction of the document at positions covered by the document depending on the size of the document supplied to the reading section, and The document conveyance condition and document size are detected by detecting the document conveyance condition and document size to the reading section based on correction data obtained by shading correction of the output value of the photoelectric conversion section of the reflected light from the reference plate. The purpose is to reduce the size and cost of the document reading device by omitting a dedicated sensor for the document reading device.

[Means to solve the problem]

In order to achieve the above object, the present invention provides: a reading unit for conveying documents of various sizes; a reference plate provided in a background position of the reading unit and providing shading correction data; and a document supplied to the reading unit. a light source that projects light onto the reference plate; a photoelectric conversion unit that receives reflected light from the reference plate and the original and photoelectrically converts the incident light; and converts the light from the reference plate into an output value of the photoelectric conversion unit In the document reading device that performs shading correction based on the reference plate, a plurality of marks are provided on the reference plate in the width direction of the document at positions covered by the document according to the size of the document supplied to the reading section, and It is characterized by detecting the conveyance status of the document to the reading section and the document size based on correction data obtained by shading-correcting the output value of the photoelectric conversion section of the reflected light from the reference plate on which the mark is applied.

Hereinafter, a detailed description will be given based on examples.

1 to 3 are diagrams showing an embodiment of the document reading device of the present invention.

FIG. 1 is a configuration diagram of the main parts of the document reading device 1, which includes a reading section 2, a reference plate 3, a light source 4, a mirror 5,
, a lens 6, a photoelectric conversion section 7, and the like.

The reading section 2 is formed of a transparent member such as transparent glass, and an original 8 is conveyed to the reading section 2 by an unillustrated original conveying means. A reference plate 3 is provided behind the reading unit 2, and a color suitable for shading correction, for example, white, is applied to the surface of the reference plate 3 on the surface of the two examples of the reading unit, as shown in FIG. As shown in (A), marks AI, A2,
A3 is provided. The marks A1, A2, and A3 are formed by placing two lines extending in the sub-scanning direction of the reference plate 3 in pairs on both sides of the reference plate 3 in the main-scanning direction at positions opposite to the center position thereof. It is formed in a predetermined color, for example, black. Marks A1, A2, A3 are
They are formed in the main scanning direction from the center of the reference plate 3 at positions that are respectively covered by the edges of a document of a predetermined size.
In the diagram (^), mark A1 is provided corresponding to the document width of A4 size document 8A, mark A2 is provided corresponding to the document width of B4 size document 8B, and mark A3 is provided corresponding to the document width of B4 size document 8B. are provided corresponding to the document width of the A3 size document 8C. In addition, in Figure 2 (A) - Fish 19
indicates the reading position.

Light is emitted from the light source 4 toward the reading position 9 of the reading section 2, and the light emitted onto the reading position 9 is reflected by the reference plate 3 or the original document 8. The light reflected by the reference plate 3 or the original 8 is irradiated onto the photoelectric conversion section 7 via the mirror 5 and the lens 6, and the light irradiated onto the photoelectric conversion section 7 is photoelectrically converted by the photoelectric conversion section 7. The photoelectric conversion unit 7 is, for example, a COD
(Charge Coupled Device)
As shown in FIG. 3, the image data photoelectrically converted by the photoelectric converter 7 is digitally converted by the A/D converter 11 and the binarization circuit 12, and then transferred to the shading circuit 13. is input. The shading circuit 13 performs shading correction based on the data in the memo January 4, and the interpolation circuit 15 converts the output of the marks Al, A2, and A3 of the photoelectric converter 7 into the mark A1.
, A2, and A3 are interpolated and corrected using nearby values. The image data subjected to shading correction by the shading circuit 13 is
It is sent to the image information determination circuit 16, and the image information determination circuit 16
Data indicating whether the document 8 is present at the reading position 9 and data regarding the size of the document 8 are output as sensor information IsD, and image data interpolated and corrected by the interpolation circuit 15 is output as image information CD.

Next, the effect will be explained.

The present invention is characterized in that the document conveyance state and document size are detected based on the output of a photoelectric conversion means of light from a mark provided on a reference plate.

That is, in FIG. 1, when reading a document, the light from the light source 8 is irradiated onto the reference plate 3 provided behind the reading unit 2, and the reference plate 3 has a light beam as shown in FIG. 2(A). Marks A1, A2, and A3 are applied. Mark A1, A
2. The light irradiated onto the reference plate 3 coated with A3 is reflected by the reference plate 3 and then enters the photoelectric conversion section 7 via the mirror 5 and the lens 6. The photoelectric conversion unit 7 photoelectrically converts the incident light and outputs it as image data to the A/D conversion unit 11 shown in FIG. After being converted, it is output to the shading circuit 13. This shading circuit 1
As shown in FIG. 2(B), the image data input to the reference plate 3 becomes a wave-shaped output due to the sensitivity variation of the photoelectric conversion element of the photoelectric conversion unit 7, and the reference plate 3 has a mark A1.
, A2, A3, so the marks A1, A2,
The output of the photoelectric conversion unit 7 of the light irradiated onto the A3 portion becomes a small value in a comb-like shape. The shading circuit 13 performs shading correction on this input image data, and the interpolation circuit 15 performs shading correction on this input image data, and in performing this shading correction, the interpolation circuit 15 performs shading correction on the input image data. The data in the portions that have been added are replaced with the values of image data near the marks A1, A2, and A3.

The image data of the reference vi3 subjected to the interpolation processing and the shading correction processing in this manner is output as image information GD shown in FIG. 2(C).

Here, when the original 8 is conveyed to the reading position 9, among the marks Al, A2, and A3 made on the reference plate 3, the marks A1, A2, and A3 are changed according to the size of the original 8. It is covered by the document 8.

Therefore, if the document 8 is B4 size that covers marks A1, A2, and A3, the shading circuit 13 detects only mark A3 corresponding to A3 size, as shown in FIG. 2(D). The image data in this state is input to the determination circuit 16, and this image data is
D is output from the determination circuit 10, and the determination circuit 16 also outputs sensor information SD informing that the document has been detected and that the document is 84 width.

Therefore, with this sensor information SD, it is possible to know that the document has arrived at the reading position 9 and the size of the document 8 that has been conveyed to the reading position 9. It does not require a sensor or a dedicated sensor to detect the document size, and
There is no need for a circuit to determine the conveyance state of the document or a circuit to determine the document size from these sensor outputs. As a result, the document reading device 1 can be made smaller and less expensive.

〔effect〕

According to the present invention, a plurality of marks are provided on the reference plate in the width direction of the document at positions covered by the document depending on the size of the document supplied to the reading section, and Based on the correction data obtained by correcting the shading of the output value of the photoelectric conversion unit of the light reflected from the reference plate, the conveyance status of the original to the reading unit and the original size can be detected. A dedicated sensor for detection can be omitted, and the document reading device can be made smaller and lower in price.

[Brief explanation of drawings]

1 to 3 are diagrams showing an embodiment of the document reading device of the present invention. FIG. 1 is a schematic diagram of the main part of the document reading device, and FIG.
A) (B) (C) (D) shows the surface of the reference plate on the reading unit side (A), the input data to the shading circuit when reading the reference plate (Fig. 2 (B)), and the judgment before conveying the document. Output image information of the circuit (Fig. 2 (C)) and output image information of the determination circuit when the document is conveyed to the reading position (Fig. 2 (D))
), and FIG. 3 is a block diagram of the document reading device. 1... Original reading device, 2... Reading unit, 3... Reference plate, 4... Light source, 5... Mirror 6. ... Lens, 7 ... Photoelectric conversion section, 8 ... Original document, 9 ... Reading position, 1 ■ ... A/D conversion section , 12...Binarization circuit, 13-...Shading circuit, 14...
・Memory, 15... Interpolation circuit, 16... Judgment circuit.

Claims (1)

[Scope of Claims] A reading unit for conveying originals of various sizes; a reference plate provided in the background of the reading unit and providing shading correction data; and a reference plate for projecting light onto the originals supplied to the reading unit. a light source; a photoelectric conversion unit that receives reflected light from the reference plate and the original and photoelectrically converts the incident light; and performs shading correction based on an output value of the photoelectric conversion unit that photoelectrically converts the light from the reference plate. In the document reading device, a plurality of marks are provided on the reference plate in the width direction of the document at positions covered by the document according to the size of the document supplied to the reading section, and What is claimed is: 1. A document reading device that detects the conveyance status of a document to a reading section and the size of the document based on correction data obtained by performing shading correction on an output value of a photoelectric conversion section of light reflected from a reference plate.