JPH11205547A - Original size detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an original size detector with which an original size can be exactly detected without erroneously detecting an original even in the case of an original such as a black frame original of different kind or type and further various originals can be dealt with. SOLUTION: Concerning the original size detector for discriminating the original size of the original by reading the length and width of an original 3 placed on an original platen 1 through an image reading means, a discolored screen 5 is provided on the lower surface of an original pressing plate 4 for pressing the original, the color of this discolored screen 5 is switched from 'black' to 'white', image reading is performed more than twice at least by an image sensor 8 and based on the discriminated result of plural read image provided from this image reading, the original size is discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document size detecting device.

[0002]

2. Description of the Related Art As shown in FIG. 9, a color copier (digital copier) currently in wide use includes a "scanner unit 11" for reading an image of a document and an image (reading) data transmitted from the scanner unit. It is composed of a "printer unit 12" for copying (printing) an original image in response. In the scanner unit 11, the image data read by the image sensor 8 is converted into yellow (Y),
The laser light is separated into magenta (M), cyan (C), and black (B) color components,
The electrostatic latent image corresponding to the document image is transmitted to 14 and is formed. This electrostatic latent image is transferred to copy paper and printed by the developing unit 15 in full color.

Conventionally, as this type of document size detecting device, there has been known a device which scans a document surface of a document and automatically determines the document size from image reading data obtained. With this document size detection device, copy paper corresponding to a document placed on a document table (contact glass) is automatically selected and fed from a paper feed unit.

The conventional document size detecting device will be described with reference to FIG. The scanner section 11 is composed of a lamp 7 (light source) for irradiating the original surface, mirrors 10 and 10 (optical system), a lens 9 for forming an image of read image data, and an image sensor 8 such as a CCD (photoelectric conversion element). By scanning the original surface of the original with a lamp, the original size is detected from a portion where the read data varies. That is, since light is reflected at a portion of the document, the reflected light is input to the image sensor 8 (white level information). On the other hand, light is not reflected at a portion of the document which is not reflected. (Black level information), and the position and size of the original are determined from the white background area (area) read by the read data (white and black level information) input to the image sensor.

[0005] In more detail in FIG. 10 this coordinate X _1, Y ₁ represents a first position where the document is detected by the image sensor 8 (white level detection), the coordinates X _2, Y ₂ is detected document This indicates a position (change from the white level to the black level) at which the document is not to be erased. The original placed on the original table has coordinates (X ₁ , X ₂ ) in the sub-scanning direction and coordinates (Y ₁ ) in the main scanning direction. , Y ₂ ) are recognized as read data of the document size of the document. In this manner, the copy sheet corresponding to the document placed on the document table (contact glass) is automatically selected by the document size detection device and fed from the paper feed unit.

The document size detection device disclosed in Japanese Patent Application Laid-Open No. 9-27898 performs document size detection, specifies a document area as a method of using document size information, and then uses only the image data. There has also been proposed a technique for simultaneously determining whether a document, which is a characteristic of the document, is a black and white document or a color document.

[0007]

However, in the case of the above-described conventional document size detecting apparatus, there is a problem that the size of the document is erroneously determined due to erroneous detection depending on the type (form) of the document. . That is, as described above, the document size is detected by scanning the document surface (main and sub scanning directions) with the light source of the lamp and detecting the position where the image reading data (black and white levels) fluctuates. Is detected. However, in recent years, "black" is frequently used for a document holding plate (pressing plate) used in a color copying machine, so there is no particular problem when the document is an ordinary "white" (white background). For example, this manuscript
As shown in FIG. 11, in the case of a black border document (the document edge is black), since the color of the document holding plate 4 "black" and the color of the document edge are the same, the document is read at the border with the document. Poor data reading may occur. In this case, since the black edge portion is not recognized as a document, the document size (size: A ′) may be erroneously determined as smaller than the actual document size (size: A) as shown in FIG.

If the document size is erroneously detected as described above, it is determined that the document size is different from the actual document size, and this size data is transmitted to the paper feeding unit, and a copy of a size different from the document size is transmitted. There is a problem that the paper is fed, which causes trouble of resetting the document (manual setting by the user) and waste of paper due to erroneous copying.

Further, in the case of the technique described in the above-mentioned publication, when recognizing a black-and-white document or a color document, a correct determination of the document area cannot be made, which may cause erroneous color determination. That is, in this publication, document recognition is performed by reading image (character) data, and document recognition is not performed by reading the edge of the document (boundary portion with the document or shading portion). Therefore, as shown in FIG. 13, a black edge document in which black characters occupy most of the image data (region a) and a region around the region a (region b) has a seal (red seal) by a seal or the like. In the case of (1), only the area a is recognized (the area a is monochrome data and the area b is color data). As a result, the original to be color-copied is black-and-white copied, which is not preferable.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional document size detecting apparatus, and to prevent erroneous determination of the document size even for documents of different types, for example, black edge documents. Accurate document size detection,
An object of the present invention is to provide a document size detecting device capable of handling various documents.

[0011]

According to the present invention, in order to achieve the above object, the invention according to the first aspect has means for determining a document size by at least two or more types. The document size is determined based on a plurality of determination results obtained from the determination means.

According to a second aspect of the present invention, in the document size detecting device, the length and width of a document placed on a document table are read by image reading means to determine the document size of the document. The means comprises a plurality of image reading means, and has a determining means for determining read data from the image reading means, and determines a document size based on a plurality of determination results obtained from the determining means. Things.

According to a third aspect of the present invention, in a document size detecting device which reads the length and width of a document placed on a document table by image reading means and determines the document size of the document, the document is suppressed. A document converting plate provided on the lower surface of the document pressing plate, and a judging device for judging data read from the image reading device. The image reading means performs image reading at least twice or more, and determines a document size based on a plurality of determination results obtained from the determination means.

According to a fourth aspect of the present invention, the largest one of the document sizes obtained from the plurality of determination results in any one of the first to third aspects is selected as the document size of the input document. It is characterized by doing.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first embodiment of the present invention shown in FIG. 1, the same parts as those in the above-described conventional example are denoted by the same reference numerals, and the description thereof will be omitted. A feature of the present invention resides in that the size of a document is accurately detected regardless of the type or form of the document. For this reason, as shown in FIG. 1, a document holding plate 4 for holding the document 3 placed on the document table 1 (contact glass 2).
A color changing screen 5 (color conversion means) is provided on the lower surface of the. A liquid crystal display panel is used for the discoloration screen 5,
In this example, the color of the document holding plate 4 can be switched from “black” to “white” by changing the liquid crystal display (see FIG. 2). Thereby, in this example, the original surface of the original 3 placed on the contact glass 2 is scanned by the lamp 7 with the color changing screen 5 switched between "black" and "white", and the image read data is imaged. It is input to each of the sensors 8 (image reading means).

As shown in FIG. 1, a first and second memories 1 for storing (reading) read data read by the image sensor 8 are used as a determination circuit of the document size detecting device.
7 and 18, a comparison circuit 19, and a CPU 20 for performing each control and signal transmission. The first and second memories 17 and 18 are connected to a comparison circuit 19, which is connected to a CPU 20. The CPU 20 is connected to a driving unit 21 for driving the scanner and a paper feeding unit 22 for feeding paper. Further, a color conversion signal is sent from the CPU 20 to the color changing screen 5, and image reading data from the image sensor 8 when the color changing screen 5 is set to "black" is stored in the first memory 17 (see FIG. Is the determination result 1). The image reading data when the color changing screen 5 is set to “white” is stored in the second memory 18 (this is referred to as a determination result 2). In the present invention, the read data in the first and second memories 17 and 18 are compared by a comparison circuit 19, and the read data (original size data) obtained from the plurality of determination results (determination results 1 and 2) are obtained. ), The largest document size is determined as the document size of the input document.

More specifically, referring to FIGS. 3 and 4, as shown in FIG. 3A, when the original 3 is set, the color changing screen 5 is "black" and the original is First, the color-changed screen 5 is scanned by the lamp 7 (see FIG. 1) in the "black" state, and the read data (document size) of the document read at this time is determined as the determination result 1. In the example shown in the figure, the original size of the original 3 is determined to be (X ′, Y ′) size.

Next, as shown in FIG.
With the discoloration screen 5 switched to “white”, scanning is performed again by the lamp 7, and the read data is used as the determination result 2.
And the original size is determined. In the example shown in the figure, the document size of the document 3 is determined to be (X, Y) size. As described above, in the present invention, of the plurality of determination results (document size data) read by the determination unit, the largest document size is determined as the document size of the input document. Therefore, in this example, (X,
Since (Y)> (X ', Y'), the (X, Y) size is determined as the document size of the input document.

Thus, as shown in FIG. 3, even when the original is a black-edge original, the read original size data is compared based on the determination results 1 and 2, and the maximum original size is input. Since the document size of the document is determined, the document size (X ′, Y ′) that is erroneously detected is not used, and the correct document size is used as the document size of the input document. That is, the erroneously detected document size is not adopted as the document size of the input document, and the document size can be automatically determined accurately regardless of the type and form of the document. Further, in this example, such image reading of the document is performed at least twice or more, so that the document detection accuracy can be further improved.

On the other hand, when the original is a normal “white” original as shown in FIG. 4, the original size (X, Y) determined by the determination result 1 and the original size determined by the determination result 2 (X ′, Y ′) and (X, Y)>
The (X, Y) size from (X ', Y') is determined as the document size of the input document. Naturally, the document holding plate is "black"
In the case of (1), the reading accuracy of the white document (document size detection) is improved. However, according to the present embodiment, the erroneous detection of the document size is prevented when the document holding plate is “white”.

Further, in the case of the present embodiment, the recognition (determination) of whether the original is a black-and-white original or a color original is performed almost simultaneously at the time of image reading by the second reading operation in the signal processing unit. As described above, image reading is performed a plurality of times (at least two or more times), and the read image data is stored and determined in the image memory each time. Therefore, a memory capacity for storing a huge amount of image data is required. Don't do it. Therefore, the cost can be reduced without using a large-capacity memory.

A second embodiment of the present invention shown in FIG.
The present invention is applied to a copying machine equipped with a DF (automatic document feeder), and the document size detecting device is constituted by the above-mentioned image reading means by the image sensor 8 and the same size sensor 24 provided in the ADF 23. I have. As shown in FIG. 1, the same-size sensor 24 is provided at a predetermined position on the document transport path 25 and has a processing circuit for determining the document size. In this example, when the document 3 set on the ADF 23 is transported by the transport rollers 26 and 27 and the transport belt 28, first, the image data (document size) of the document 3 is read by the equal-size sensor 24, and The read data is stored (stored) in the first memory 17 (determination result 1).

The image data of the original 3 conveyed on the contact glass 2 is read again by the image sensor 8, and the read data is stored (stored) in the second memory 18 (judgment result 2). The reading of each of these read data is performed at least two times as in the first embodiment.
More than once, and each read data is
And the maximum document size is determined as the document size of the input document. Also, in this example, since the transport belt 28 corresponds to a document holding plate for holding down the original, if the transport belt 28 is provided with a function as a “color changing screen”, as described above, it can support various originals. Therefore, the document size can be detected more accurately.

The third embodiment of the present invention shown in FIGS. 6 to 8 comprises an image sensor (see FIG. 5) and a light reflection type sensor. In this example, as the light reflection type sensor,
An APS sensor 29 is employed. This APS sensor 29
6 is provided at a predetermined position below the contact glass 2 on which the document 3 is placed, as shown in FIGS. This A
As shown in FIG. 8, the PS sensor 29 includes a light emitting element 30 (LED) for irradiating the original surface of the original with LED light and a light receiving element.
And a grating element 32 provided above the light emitting element 30. The light emitted from the light emitting element 30 passes through the grating 32 as shown in FIG. 3, is dispersed into three directions of light beams, and irradiates the original with the plurality of light beams. Then, the size of the original is detected by detecting the light reflected from the original 3 by the light receiving element 31. This document size determination is performed based on a detection situation (determination table) based on a combination of the presence or absence of the output of the APS sensor set in advance.
The determination of the document size is performed when the document holding plate 4 is closed and when the switch 33 for detecting the opening / closing is detected (see FIG. 7).

In the case of this embodiment, as in the first embodiment, the original size data (judgment result 1) detected by the APS sensor 29 and the image sensor 8 (FIG. 5)
The comparison circuit 19 compares the original size data (judgment result 2) read by the comparison circuit 19, and determines the maximum original size as the original size of the input original. In addition, since the discoloration screen 5 is provided on the document holding plate 4, the document size can be accurately detected and various documents can be handled as described above. In addition, A
When the PS sensor 29 is used, a predetermined position on the contact glass 2 (40 to
50 mm), it is possible to avoid erroneous document detection due to disturbance light or the like.

As described above, according to the original size detecting apparatus of the present invention, the position of the original and the original size can be accurately and automatically determined. Various image processing such as scaling, image movement, and the like can be easily performed. Although the embodiment has been described with reference to a color copying machine, the present invention can be applied to an image recognition apparatus such as a facsimile, an electronic filing apparatus, and an OCR.

[0027]

The present invention is as described above. According to the first aspect of the present invention, there is provided means for determining a document size by at least two or more types, and the original size is obtained from the determining means. Since the document size is determined based on the plurality of determination results, there is an effect that the document size can be accurately determined without erroneously detecting the document size.

According to a second aspect of the present invention, in the document size detecting device, the length and width of a document placed on a document table are read by image reading means to determine the document size of the document. The means comprises a plurality of image reading means, and has a judging means for judging data read from the image reading means, and determines the document size based on a plurality of judgment results obtained from the judging means. There is an effect that the document size can be accurately determined without erroneous detection.

According to a third aspect of the present invention, in a document size detecting device which reads the length and width of a document placed on a document table by image reading means and determines the document size of the document, the document is suppressed. A document converting plate provided on the lower surface of the document pressing plate, and a judging device for judging data read from the image reading device. The image reading unit performs at least two image readings and determines the size of the document based on the plurality of determination results obtained from the determination unit. The document size can be accurately detected without erroneous detection of the document size, and it is possible to cope with various documents.

According to a fourth aspect of the present invention, the largest one of the document sizes obtained from the plurality of determination results in any one of the first to third aspects is selected as the document size of the input document. Therefore, even if the document is of a different type, such as a black edge document, the document size of the document is not erroneously detected, the document size can be accurately detected, and various documents can be handled.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a first embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional view showing a change of the color changing screen of the above.

FIG. 3 is an explanatory diagram showing a state of detecting a black edge document size according to the first embodiment;

FIG. 4 is an explanatory diagram showing a state of detecting a document size of a white document according to the first embodiment;

FIG. 5 is a schematic longitudinal sectional view of the second embodiment.

FIG. 6 is a schematic perspective view of the third embodiment.

FIG. 7 is a schematic longitudinal sectional view showing the document size detecting device according to the third embodiment.

FIG. 8 is a perspective view showing the APS sensor according to the first embodiment.

FIG. 9 is a vertical sectional front view of a conventional document size detecting device of the same type as the present invention.

FIG. 10 is a schematic plan view showing a detection method of the document size detection device of the above.

FIG. 11 is a plan view showing an example of a black edge document.

FIG. 12 is a schematic vertical sectional view showing a reading state of a black edge document by a conventional document size detecting device.

FIG. 13 is a plan view showing a black-edged document stamped.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 platen 2 contact glass 3 document 4 document holder 5 color changing screen 7 lamp 8 image sensor 9 lens 10 mirror 17, 18 first and second memories 19 comparison circuit 20 CPU 21 drive unit 22 paper feed unit 29 APS sensor

Claims (4)

[Claims] 1. A document size detecting device, comprising: means for determining a document size by at least two or more types, and determining a document size based on a plurality of determination results obtained from the determination means. . 2. A document size detecting device for reading the length and width of a document placed on a platen by an image reading means to determine a document size of the document, wherein the image reading means comprises a plurality of image reading means. And determining means for determining read data from the image reading means,
A document size detection device, wherein a document size is determined based on a plurality of determination results obtained from the determination means. 3. An original size detecting device for reading the length and width of an original placed on an original plate by an image reading means and determining the original size of the original has an original holding plate for suppressing the original. A color conversion means is provided on the lower surface of the document holding plate, and a determination means for determining read data from the image reading means is provided.Alternatively, the color conversion means is changed in color and at least by the image reading means. A document size detecting device which performs image reading two or more times and determines a document size based on a plurality of determination results obtained from the determination means. 4. The document size detection device according to claim 1, wherein the largest one of the document sizes obtained from the plurality of determination results is selected as the document size of the input document. apparatus.