JP2003152968A - Document reading method and document reading device - Google Patents

Abstract

(57) [Summary] [Problem] With a simple structure and a simple operation by an operator,
Outputs image data without show-through. SOLUTION: The light amount of a light source is set to a first light amount to read first image data, and the light amount of a light source is set to a second light amount lower than the first light amount to read second image data.
It is stored in the image memory (steps S11, S12). Then, the image pattern of the first image data is compared with the image pattern of the second image data (steps S13 and S1).
4) If the first image data and the second image data are identical as a result of the collation, the first image data is selected as output image data (step S15), and the first image data and the second image data are If they are different, the different parts are deleted from the first image data and selected as output image data (step S16), and printed out (steps S17 and S18).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading method and a document reading apparatus document reading method capable of reading a document image having images formed on both sides of a sheet.

[0002]

2. Description of the Related Art In recent years, there have been many opportunities to read an image from a document having images formed on both sides of a sheet. However, if there is an image on the back side of the document and the paper thickness of the document is thin, the image on the back side is also transparent when the image on the front side is read, and the read image on the back side appears on the read image on the front side. A phenomenon called "show-through" may occur. This show-through has caused a problem that the quality of the read image is significantly deteriorated.

As a means for solving such a problem, there is a document conveying apparatus disclosed in Japanese Patent Laid-Open No. 1-318460. When there are images on both sides of a document to be read, this document feeder lowers the amount of light from the light source for reading the document by turning on the double-sided document setting button by the operator of the document feeder. Was prevented.

Further, a reflection type sensor or a transmission type sensor is provided on the upstream side of the conveying roller to detect the reflected light on the back surface of the original conveyed to the platen glass, and further, an original thickness sensor is provided to detect the original. There is also a method of measuring the thickness and controlling the light amount of the light source based on the thickness of the document.

[0005]

However, in the conventional document conveying apparatus, the image data actually read is not analyzed to automatically determine whether the show-through occurs or not. There is a problem that the operator himself needs to turn on the double-sided original setting button.

Further, in the above-mentioned method of automatically preventing show-through, it is necessary to provide a reflection type sensor, a transmission type sensor or a document thickness sensor as an additional component for measuring the document thickness, and the operator There is a problem that the operation of is complicated and the structure of the document reading device is complicated.

The present invention was devised to solve such a problem and is easy for an operator to operate, and
It is an object of the present invention to provide a document reading method and a document reading device in which the structure of the document reading device is simple and the show-through does not occur.

[0008]

An image reading method according to the present invention has a light source for irradiating a document image with light while scanning the surface of the document image, and reading the image data from the light reflected by the surface of the document image. A method comprising: setting a light amount of a light source to a first light amount to read first image data; and setting a light amount of a light source to a second light amount lower than the first light amount to read second image data. , The step of matching the image pattern of the first image data with the image pattern of the second image data, and as a result of the matching, if the first image data and the second image data are the same, the first image data is Selecting the output image data, and selecting the second image data as the output image data when the first image data and the second image data are different from each other.

According to the present invention, image patterns obtained by scanning two times with different amounts of light are collated, and as a result of this collation, it is determined whether or not the two image patterns match.
Since the output image data is selected, it can be implemented using a conventional image reading device.

The image reading method of the present invention is a method of reading an original having a light source for irradiating the original image with light while scanning the original image surface and reading image data from the light reflected on the original image surface. Reading the first image data by setting the first light amount to the first light amount; reading the second image data by setting the light amount of the light source to the second light amount lower than the first light amount; And the step of matching the image pattern of the second image data with each other, and when the result of the matching is that the first image data and the second image data are the same, the first image data is selected as the output image data. , When the first image data and the second image data are different, a different area is extracted, the extracted area is deleted from the first image data, and the first image data after the deletion is used as output image data. And selecting, is made of.

According to the present invention, image patterns obtained by scanning two times with different amounts of light are collated, and when the two image patterns do not match as a result of this collation, image processing is performed to perform back processing. Since the image data having no image is output, it can be implemented by using the conventional image reading apparatus.

The document reading apparatus of the present invention includes a light source for irradiating a document image with light while scanning the document image surface, a scanning reading unit for reading image data from the light reflected on the document image surface, and the scanning reading unit. A document reading device, which is provided so as to be able to come into contact with and separate from the document and pivotally rotatable, and has a document pressing unit for bringing a document image into close contact with the scanning reading unit, wherein the document pressing unit contacts the scanning reading unit. When
An original pressing mat that can be moved between a first position where the original is brought into close contact with the scanning and reading means and a second position where the original is separated from the image surface of the original by a predetermined distance, and the original pressing mat is provided at the first position or the second position. And a control / processing means for performing image processing on the image data read by the scanning / reading means and controlling the scanning / reading means, the document pressing means, and the moving means. And so on.

According to the present invention, the original image is scanned and read while the original pressing mat is kept stationary at two different positions, the image patterns obtained by the scanning and reading at the respective positions are collated, and the collation result is obtained. It is possible to output an image without show-through by performing image processing based on

Further, the control / processing means is read when the document holding mat is at the second position and the image pattern of the first image data read when the document holding mat is at the first position. As a result of checking the image pattern of the second image data, if the first image data and the second image data are different, a different area is extracted from the first image data, and the extracted area is used as the first image data. It is possible to delete the data from the image data to obtain output image data. In this case, it is possible to obtain image data without show-through by deleting the extracted area from the first image data.

An image reading method of the present invention is an original reading method which is carried out by using the original reading apparatus having the above-mentioned structure, wherein the moving means moves the original pressing mat to a first position, and the scanning reading means operates. A step of reading the first image data; a step of moving the document holding mat to the second position by the moving means, and reading the second image data by the scanning reading means; and an image of the first image data by the control / processing means. The step of collating the pattern with the image pattern of the second image data, and as a result of the collation, when the first image data and the second image data are the same, the first image data is selected as the output image data, and the first image data is selected. When the image data and the second image data are different from each other, the step of selecting the second image data as the output image data.

According to the present invention, the document image is scanned and read while the document pressing mat is kept stationary at two different positions, and the two images are read by scanning at each position.
Two image patterns are collated, and when the two image patterns do not coincide as a result of this collation, image processing is performed to output image data without show-through, which simplifies the operator's operation. be able to.

An image reading method of the present invention is an original reading method which is carried out by using the original reading apparatus having the above-mentioned structure, wherein the moving means moves the original pressing mat to a first position, and the scanning reading means operates. A step of reading the first image data; a step of moving the document holding mat to the second position by the moving means, and reading the second image data by the scanning reading means; and an image of the first image data by the control / processing means. The step of collating the pattern with the image pattern of the second image data, and as a result of the collation, when the first image data and the second image data are the same, the first image data is selected as the output image data, and the first image data is selected. When the image data and the second image data are different, a different area is extracted, the extracted area is deleted from the first image data, and the first image data after the deletion is output. And selecting as image data, it is made of.

According to the present invention, the original image is scanned and read while the original pressing mat is stationary at two different positions, and the original image is read by scanning at each position.
Two image patterns are collated, and when the two image patterns do not coincide as a result of this collation, image processing is performed to output image data without show-through, which simplifies the operator's operation. be able to.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a document reading method and a document reading apparatus according to the present invention will be described below.

[First Embodiment] First, a first embodiment of the document reading method of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view showing an example of a document reading apparatus used when carrying out the first embodiment of the document reading method of the present invention. The light (including reflected light) illustrated in FIG. 1 is indicated by a broken line L1.

As shown in FIG. 1, a document reading apparatus used when carrying out the document reading method of the first embodiment is a document consisting of an operation section 1, a scanner section 2, and an ADF (auto document feeder) 3. An M that is connected to the reading unit, the operation unit 1 and the scanner unit 2 and includes an image processing unit 4a.
It is composed of a CU (main control unit) 4, an image memory 5 connected to the MCU 4, and a printer section 6 (details of the printer section 6 will be described later).

The operation unit 1 instructs the MCU 4 to start copying based on the setting of copy conditions such as the number of copies and the density of the copy by the operator and the instruction to start copying. MCU4
Instructs the scanner unit 2 to start copying.

The original reading unit AD the set original.
F3 automatically conveys it to the scanner unit 2.

The scanner unit 2 includes, for example, a copy lamp 21a formed of a fluorescent lamp (for example, a xenon lamp) and a first lamp.
Mirror 21c, second mirror 24a, third mirror 24b,
Imaging lens 22 and CCD (charge couple)
red device) 23. The copy lamp 21a irradiates the document with light. Then, the reflected light from the document surface is reflected by the first mirror 21c, the second mirror 24a, and the third mirror 24b, and then enters the CCD 23 through the imaging lens 22. Then
The reflected light incident on the CCD 23, that is, the image information is converted into an electric signal and transmitted to the MCU 4. In MCU4,
The transmitted image information is transmitted to the image memory 5, and the image memory stores the transmitted image information as image data.

The structure of the scanner unit 2 will be described in more detail with reference to the drawings.

FIG. 2 is an explanatory diagram showing an example of a scanner section which constitutes the document reading apparatus shown in FIG. The light (including the reflected light) illustrated in FIG. 2 is indicated by a broken line L1.

The scanner section 2 has the configuration shown in FIG.
Mirror unit 24, copy lamp unit 21, scanner unit 25, platen glass 2 on which an original is placed
6 (shown in FIG. 1) and a white plate 27 for shading correction.

The scanner unit 25 is a reading section of the digital optical system.

The copy lamp unit 21 is composed of a copy lamp 21a, a reflector (light condensing plate) 21b and a first mirror 21c, and reciprocates below the document placed on the platen glass 26 at a predetermined speed. It is like this. The light emitted from the copy lamp 21a passes through the platen glass 26 and reaches the original image,
The light is reflected on the surface of the original and is reflected by the first mirror 21c in a predetermined direction.

The mirror unit 24 includes a second mirror 24a.
And a third mirror 24b, and the reflected light from the first mirror 21c is reflected by the second mirror 23a and the second mirror 23b in a predetermined direction.

The mirror unit 24 of the scanner section 2 is driven by a mirror motor 28. A home position sensor (not shown) is provided as a sensor for detecting the home position of the copy lamp unit 21.

In the document reading apparatus of the present invention, in order to read a document image, the reflected light from the document obtained by irradiating the copy lamp 21a as a light source is reflected by three mirrors (that is, the first mirror 21c). , The second mirror 24a and the third mirror 24b) and the imaging lens 22 through the CCD
The light (light energy) formed on the CCD 23 is converted into an electric signal (analog signal) by the CCD 23 (that is, photoelectric conversion is performed), and an output signal (analog signal) from the CCD 23 is converted into a digital signal (analog signal). image data)
A procedure is adopted in which the digital signal is converted (A / D converted) to the MCU 4 and then transmitted to the MCU 4, and then the digital signal is further transmitted to the image memory 5 by the MCU 4.

The MCU 4 is an ASIC (applicat).
ion specific integrated c
ircuit) or CPU (central pro)
processing unit), which receives a signal indicating a document image read by the scanner unit 2 and sends the signal to the image memory 5 as image data. Also,
When the image data is received from the image memory 5, after the image processing is performed under the condition set in the operation unit 1, the image data after the image processing is used as print data in the LSU (laser scanning unit) 61 of the printer unit 6. Send.

Next, the configuration of the printer unit 6 is shown in FIG.
Will be described with reference to.

The printer unit 6 includes an LSU 61 composed of a laser diode, a polygon mirror, a lens and the like, a process unit 62, a fixing unit 63, a paper transport unit 64, an image transfer unit 65, a cassette paper feed unit 66a and a manual feed. The sheet feeding unit 66 includes a sheet feeding unit 66b.

The LSU 61 emits a laser beam L2 (converts an electrical signal into an optical signal) according to the print data transmitted from the MCU4. This laser light L2 passes through a polygon mirror and various lenses, and is then passed through the OP of the process unit 62.
C (Organic Photo Conductor)
r) Irradiation onto the drum 62a.

In the process section 62, the laser beam L2 is irradiated to form an electrostatic latent image on the OPC drum 62a, which is developed into a visible image (toner image).

On the other hand, the paper is fed from the paper feed unit 66, and P
The image is sent to the image transfer unit 65 at a timing when the front end of the toner image and the transfer start position of the paper can be synchronized by the S roller (not shown). After the toner image is transferred onto the paper, the fixing unit 63 fixes the toner image, and the paper on which the toner image is fixed is discharged onto a paper discharge tray (not shown) (in FIG. 1). The paper discharge direction is indicated by arrow A).

In the present embodiment, the document reading unit includes the scanner unit 2 and the ADF 3, and the document is A
Platen glass 2 of scanner unit 2 automatically by DF3
6 is to be conveyed. However, the present invention is not limited to this form, and may be a document reading unit not provided with the ADF 3, and in this case, if the document is manually placed on the platen glass 26 and the image data is read. Can handle.

Next, when an image reading method is carried out by using the image reading apparatus having the above-described structure, that is, when a document having images formed on both sides (hereinafter, also referred to as "double-sided document") is read. A procedure for erasing a show-through image that occurs by performing image processing will be described.

FIG. 3 is a flow chart showing an embodiment of the image reading method of the present invention. Further, FIG. 4 is a graph showing an example of the density level of read data obtained in the process of carrying out the image reading method shown in FIG.

First, when an operator places a double-sided original to be read on the sheet placing portion of the ADF 3, the ADF 3 conveys the double-sided original one by one onto the platen glass 26, and scans and reads the image on the double-sided original. Work is performed (step S
1). This scanning and reading operation is performed twice with the same double-sided original document left on the platen glass 26. The first time, the light quantity of the copy lamp (for example, a xenon lamp with a drive voltage of 1.5 KV) 21a is set to a light quantity corresponding to a normal output, and reading is performed.
The light amount of 1a is set to 80% of the light amount of the first copy lamp 21a.
Reading is performed by setting the light amount to ± 5%.

By performing the reading in such a procedure, as the first read data read at the first time, data without show-through or data with show-through is obtained, and is read at the second time. As the second read data,
Data without show-through or data with a density level of the image on the back side smaller than a predetermined level can be obtained.

FIG. 4A shows the density level of the first read data in the case where the show-through data is obtained as the first read data. In FIG. 4A, the left side shows the density level of the image on the front side, and the right side shows the density level of the image on the back side that has been erroneously read. Here, since the density level of the back side image that has been erroneously read is higher than the predetermined level (shown by the broken line B), CC
The first image data (image data obtained by the first reading) output from the CCD 23, which is determined to be the black level in D23, includes data relating to the image on the back surface.

Further, FIG. 4B shows the density level of data in which the density level of the image on the back side is smaller than the predetermined level as the second read data. In FIG. 4B, the left side shows the density level of the image on the front side, and the right side shows the density level of the image on the back side that has been erroneously read. Here, since the density level of the image on the back surface that has been erroneously read is smaller than the predetermined level B, the CCD 23 determines that the image is a white level, and the second image data output from the CCD 23 (obtained by the second reading). Image data) does not include data about the back side image.

After that, the first image data and the second image data are stored in the image memory 5 via the MCU 4 (step S2).

After that, the first image data and the second image data stored in the image memory 5 are input to the image processing section 4a of the MCU 4 and recognized as image patterns in the image processing section 4a. The image processing unit 4a collates the two recognized image patterns (step S3).

As a result of the collation, when it is determined that the two image patterns match and no show-through has occurred (when the determination result in step S4 is "YES"),
The first image data is selected as the image data to be output (step S5).

On the other hand, as a result of the collation, the two image patterns do not match, that is, the image pattern obtained in the first scanning and reading operation has a black level (a density level higher than a predetermined level). However, when it is determined that the image pattern obtained by the second scanning and reading operation has the white level and the show-through has occurred (when the determination result in step S4 is “NO”). , The second image data,
Select as image data to be output (step S
6).

When it is determined that the show-through has not occurred, the selected first image data has a sufficient density level, and therefore the MCU 4 transmits the first image data to the printer unit 6 as it is. Yes (step S7).

On the other hand, when it is determined that the show-through has occurred, the selected second image data does not maintain a sufficient density level (that is, the graph shown on the left side in FIG. 4A). 4) and the density level of the graph shown on the left side in FIG. 4B, the density level is smaller than usual). Image processing unit 4a
(Step S8). Then, the second image data is transmitted from the MCU 4 to the printer unit 6 (step S
7).

Finally, the printing section 6 prints an image based on the first image data or the second image data on a sheet by using the procedure described above (step S9).

In the image reading method described above, when the result of the collation indicates that the show-through has occurred in the image processing unit 4a, the image is printed on a sheet using the second image data. However, the procedure is not limited to this. Another embodiment of the image reading method will be described below.

FIG. 5 is a flow chart showing another embodiment of the image reading method. Here, up to the step of collating the first image data and the second image data (steps S11 to S13), the same steps as the image reading method described with reference to FIG. 3 (steps S1 to S3). Is performed, the description up to the step of collating the first image data and the second image data will be omitted.

As a result of the collation, when it is determined that the two image patterns match each other (when the determination result in step S14 is "YES"), as in the image reading method described above, One image data is selected as the image data to be output (step S15) and transmitted from the MCU 4 to the printer unit 6 (step S17).

On the other hand, as a result of the collation, when it is determined that the two image patterns do not match (when the determination result in step S14 is "NO"), the first scanning reading work is performed. The image pattern obtained has a black level (a density level higher than a predetermined level), but the image pattern obtained by the second scanning and reading operation has a white level. Image processing such as extracting and removing) in the image processing unit 4a.
This is performed on the image data (step S16). Then, the first image data after the image processing is selected as the image data to be output and transmitted from the MCU 4 to the printer unit 6 (step S17).

Finally, the printing unit 6 prints an image based on the first image data on a sheet by using the procedure described above (step S18). According to the document reading method of the first embodiment, each scanning is performed. Scanning is performed twice by changing the light amount at the time of reading, and the image patterns to be output are selected by comparing the image patterns obtained by the two scanning readings with the density level as a reference, and the second image data is selected. If is selected,
Furthermore, since the image processing is performed so that the image data has a predetermined density or higher and the image is printed out, the problem that occurred in the conventional document reading apparatus without changing the configuration of the conventional document reading apparatus. Can be solved.

In the second embodiment, the scanning and reading operation is performed twice not only for the double-sided original but also for the single-sided original having no image on the back side. You may make it work.
Specifically, a double-sided image button may be provided on an LCD (liquid crystal display) panel that constitutes the operation unit 1, and the scanning and reading operation may be performed twice only when the operator turns on the double-sided image button.

[Second Embodiment] Next, a second embodiment of a document reading apparatus of the present invention and a document reading method implemented by using the document reading apparatus will be described with reference to the drawings.

FIG. 6 is an explanatory view showing an example of an OC mat and an OC mat moving mechanism which constitute the second embodiment of the document reading apparatus of the present invention. In addition, FIG. 7 shows O shown in FIG.
It is a perspective view which expands and shows a C mat movement mechanism.

In the document reading apparatus and the document reading method of the second embodiment, the OC (original cover) mat used as the document holding mat is not changed but the light intensity of the copy lamp is changed. The feature is that image data without show-through is output by performing scanning and reading work on the original image in this state. Therefore, the document reading apparatus according to the second embodiment does not have a mechanism for changing the light amount of the copy lamp in two steps, but has a mechanism for vertically moving the OC mat. The configuration other than these mechanisms is the same as that of the document reading apparatus (document reading apparatus shown in FIG. 1) in the first embodiment described above. Therefore, if necessary in the following description, the reference numerals of the respective constituent members of the document reading apparatus shown in FIG. 1 will be used.

First, the OC structure will be described.

In the OC structure, as shown in FIG. 6, the OC mat 31 is vertically movably housed in a mat housing portion 38 formed on the lower surface of the OC exterior 30.
The C mat 31 has a plurality of first wires 32a, 32b, 32
The structure is suspended by c and 32d.
That is, the plurality of first wires 32a, 32b, 32c,
One end of 32d is fixed to the upper surface of the OC mat 31, and the other end is fixed to each of the plurality of first pulleys 35a, 35b, 35c, 35d arranged above it. Also, the plurality of first pulleys 35a, 35
One end of the second wire 34 is fixed to b, 35c, and 35d, and the other end of the second wire 34 is fixed to the shaft 37a of the solenoid 37 via the second pulley 36.

Further, the OC mat 31 and the mat storing section 38
A plurality of compression coil springs 33a, 33b, 33c for urging the OC mat 31 downward are provided at predetermined intervals between the upper surface and the top surface.

FIG. 7 shows the structure of the first wire 32a and the second wire 34 wound around the first pulley 35a.

Two first wires 32a are actually provided on the left and right sides of the first pulley 35a (the back side and the front side in FIG. 6) with the second wire 34 interposed therebetween. The other end of the first wire 32a has its tip fixed while being wound around the first pulley 35a in multiple layers.
The other end of the wire 34 is also fixed at its tip end while being wound around the first pulley 35a in multiple layers. However, the first wire 32a and the second wire 34 are wound in opposite directions. In this state, the first
The wire 32a includes coil springs 33a, 33b, 3
Since it is always urged downward by 3c, the first pulley 35a is always urged to rotate in the direction indicated by arrow R. Although not shown in the drawing, such a structure has other first wires 32b, 32c, 32d and a second wire.
The same applies to the wire 34 and the first pulleys 35b, 35c, 35d.

In such an OC structure, when the shaft 37a of the solenoid 37 is at the first position (the position shown in FIG. 6A) protruding from the upper surface of the solenoid 37,
The second wire 34 is pulled out, and accordingly, the first pulleys 35a, 35b, 35c, 35d rotate in the direction indicated by the arrow R, so that the lower surface of the OC mat 31 has the OC exterior 30.
It is flush with the bottom surface of. Therefore, OC mat 31
Is in contact with the top of the document.

On the other hand, the second position (the position shown in FIG. 6B) in which the shaft 37a of the solenoid 37 is retracted.
, The second wire 34 is pulled back, and accordingly, the first pulleys 35a, 35b, 35c, 35d rotate in the direction indicated by the arrow L, so that the first wires 32a, 3
2b, 32c and 32d are first pulleys 35a, 35b and 3
The lower surface of the OC mat 31 is positioned above the lower surface of the OC exterior 30 by a distance X (upper side of the mat housing portion 38). Therefore, the OC mat 31 is arranged above the document and is held in a non-contact state with the document.

Next, a method of reading an original image using the image reading apparatus having such a structure will be described with reference to the flowchart shown in FIG.

First, as shown in FIG. 6A, the shaft 37a of the solenoid 37 is moved to the first position so that the lower surface of the OC mat 31 and the lower surface of the OC exterior 30 are flush with each other.
In this state, one document is conveyed on the platen glass 26 and held at a predetermined position. Then, the scanner unit 2 is operated to scan and read the original image (step S2).
1). The read image data is stored in the image memory 5 as the first image data (step S22).

After that, as shown in FIG. 6B, the shaft 37a of the solenoid 37 is moved to the second position, and the OC
The lower surface of the mat 31 is located above the lower surface of the OC exterior 30 by a distance X. In this state, the scanner unit 2 is operated to scan and read the document image that is still placed on the platen glass 26, as in the case of obtaining the first image data (step S23). The read image data is stored in the image memory 5 as the second image data (step S24).

Then, the image reading method is carried out by using the first image data and the second image data. Specifically, first, the first image data and the second image data are input to the image processing unit 4a of the MCU 4, and the image processing unit 4a
In a, each is recognized as an image pattern. The image processing unit 4a collates the two recognized image patterns (step S25).

As a result of the comparison, if the two image patterns match and it is determined that no show-through has occurred (when the determination result in step S26 is "YES"), the first image The data is selected as the image data to be output (step S27).

On the other hand, as a result of the collation, the two image patterns do not match (the determination result in step S26 is "N").
O ”), that is, an area obtained at the black level (a density level equal to or higher than a predetermined level) in the image pattern obtained by the first scanning reading operation is an image obtained by the second scanning reading operation. If the pattern has a white level and it is determined that show-through has occurred, the second image data is selected as the image data to be output (step S).
28).

If it is determined that the show-through has not occurred, the selected first image data has a sufficient density level. Therefore, the first image data is sent from the MCU 4 to the printer unit 6 as it is. Send (step S2
9).

On the other hand, when it is determined that the show-through has occurred, the selected second image data does not maintain a sufficient density level (that is, the light amount of the second scanning / reading operation is the first one). (Because it is less than the light intensity of scanning and reading work)
The image processing unit 4a performs image processing of increasing the density level of the second image data over the entire area (step S3).
0). After that, the second image data is transmitted from the MCU 4 to the printer unit 6 (step S31).

Finally, the printing section prints an image based on the first image data or the second image data on a sheet by using the procedure described above (step S32).

In the above-mentioned image reading method, when the result of the collation indicates that the show-through has occurred in the image processing section 4a, the image is printed on a sheet using the second image data. However, the procedure is not limited to this. Another example of the image reading method according to the second embodiment will be described below.

FIG. 9 is a flowchart showing another example of the image reading method according to the second embodiment. Note that here, up to the step of collating the first image data and the second image data, the same steps (steps S21 to S25) as the image reading method described with reference to FIG. Step of collating 1st image data and 2nd image data (step S41 to step S45)
The description up to is omitted.

As a result of the collation, when it is determined that the two image patterns match (when the determination result in step S46 is "YES"), as in the image reading method described above, One image data is selected as the image data to be output (step S47) and transmitted from the MCU 4 to the printer unit 6 (step S48).

On the other hand, as a result of the collation, when it is determined that the two image patterns do not match (when the determination result in step S46 is "NO"), the first scanning reading operation is performed. The image pattern obtained has a black level (a density level higher than a predetermined level), but the image pattern obtained by the second scanning and reading operation has a white level. Image processing such as extracting and removing) in the image processing unit 4a.
This is performed on the image data (step S49). Then, the first image data after the image processing is selected as the image data to be output and transmitted from the MCU 4 to the printer unit 6 (step S48).

Finally, the printing section prints an image based on the first image data on a sheet by using the procedure described above (step S50).

According to the document reading apparatus and the document reading method of the second embodiment, the OC structure is configured so that the OC mat can be moved in the vertical direction so that the OC mat and the document are in contact with each other and are not in contact with each other. In each of the states, scanning and reading are performed with a constant light amount of the copy lamp, and the image patterns obtained by the two scanning readings are compared with each other based on the density level to select the image data to be output. , When the second image data is selected,
Since the image processing is performed so that the image data has a predetermined density or more and is printed out, the operator's operation can be simplified.

[0085]

According to the image reading method of the present invention, image patterns obtained by two scanning readings with different light amounts are collated,
As a result of this matching, the output image data is selected depending on whether or not the two image patterns match, so that it is possible to output an image without show-through with the configuration of the conventional image reading apparatus. .

According to the document reading device of the present invention and the document reading method using the document reading device, the document image is scanned and read while the document pressing mat is kept stationary at two different positions, and the respective positions are read. The two image patterns read by the scanning in step 1 are collated, the image processing is performed based on the collation result, and the image without the show-through is output, so that the operation of the operator is simplified. be able to.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a document reading apparatus used when carrying out a first embodiment of a document reading method of the present invention.

FIG. 2 is an explanatory diagram showing an example of a scanner unit that constitutes the document reading apparatus shown in FIG.

FIG. 3 is a flowchart showing an embodiment of an image reading method of the present invention.

FIG. 4 is a graph showing an example of the density level of read data obtained in the process of carrying out the image reading method shown in FIG.

FIG. 5 is a flowchart showing another embodiment of the image reading method of the present invention.

FIG. 6 is an explanatory diagram showing an example of an OC mat and an OC mat moving mechanism that constitute Embodiment 2 of the original reading device of the present invention.

7 is an enlarged perspective view showing a part of the OC mat moving mechanism shown in FIG. 6, showing a structure of a first wire and a second wire wound around a first pulley 35. FIG.

FIG. 8 is a flowchart showing an example of an image reading method according to the second embodiment.

FIG. 9 is a flowchart showing another example of the image reading method according to the second embodiment.

[Explanation of symbols]

1 Operation part 2 Scanner section 3 ADF 4 MCU 4a Image processing unit 5 image memory 6 Printer section 30 OC exterior 31 OC mat 32a, 32b, 32c, 32d 1st wire 33a, 33b, 33c Compression coil spring 34 Second wire 35a, 35b, 35c, 35d First pulley 36 Second pulley 37 Solenoid

Claims (6)

[Claims] 1. A document reading method comprising a light source for irradiating a document image with light while scanning the document image surface, and reading image data from light reflected by the document image surface, wherein the light amount of the light source is a first light amount. To read the first image data, the step of reading the second image data by setting the light amount of the light source to the second light amount lower than the first light amount, the image pattern of the first image data and the first image data The step of collating the image pattern of the two image data, and as a result of the collation, when the first image data and the second image data are the same, the first image data is selected as the output image data and And a step of selecting the second image data as the output image data when the second image data is different from the second image data. 2. A document reading method for reading image data from light reflected on a document image surface, comprising a light source for irradiating the document image with light while scanning the document image surface, wherein the light amount of the light source is a first light amount. To read the first image data, the step of reading the second image data by setting the light amount of the light source to the second light amount lower than the first light amount, the image pattern of the first image data and the first image data The step of collating the image pattern of the two image data, and as a result of the collation, when the first image data and the second image data are the same, the first image data is selected as the output image data and When the second image data is different, a different area is extracted, the extracted area is deleted from the first image data, and the deleted first image data is selected as output image data. Document reading method characterized by comprising. 3. A light source for irradiating an original image image with light while scanning the original image surface, a scanning reading unit for reading image data from the light reflected on the original image surface, and a contacting / separating unit for the scanning reading unit. An original reading device which is pivotally provided and has an original pressing means for bringing the original image into close contact with the scanning reading means, wherein the original pressing means is an original when contacting the scanning reading means. An original pressing mat that can be moved between a first position where it is in close contact with the scanning and reading means and a second position that is separated from the image surface of the original by a predetermined distance, and the original pressing mat is the first position or the second position. And moving means for moving the image data read by the scanning and reading means, and control and processing means for controlling the scanning and reading means, the document holding means and the moving means. Document reading apparatus characterized by comprising a. 4. The control / processing means is read when the document holding mat is at the second position and the image pattern of the first image data read when the document holding mat is at the first position. As a result of checking the image pattern of the second image data, if the first image data and the second image data are different, a different area is extracted from the first image data, and the extracted area is used as the first image data. 4. The document reading device according to claim 3, wherein the output image data is obtained by erasing from the document reading device. 5. A method of reading an original using the original reading apparatus according to claim 3, wherein the moving means moves the original pressing mat to a first position, and the scanning means reads the first image data. And a step of moving the document holding mat to the second position by the moving means and reading the second image data by the scanning and reading means, and an image pattern of the first image data and the second image data by the control / processing means. When the first image data and the second image data are the same as a result of collating with the image pattern of the image data, the first image data is selected as the output image data, and the first image data and the second image data are selected. And a step of selecting the second image data as the output image data when the two image data are different from each other. 6. A document reading method carried out using the document reading device according to claim 3, wherein the moving means moves the document holding mat to a first position, and the scanning reading means A step of reading the first image data; a step of moving the document pressing mat to a second position by the moving means, and reading the second image data by the scanning reading means; and an image of the first image data by the control / processing means. A step of collating the pattern with the image pattern of the second image data, and as a result of the collation, when the first image data and the second image data are the same, the first image data is selected as the output image data, and the first image data is selected. When the image data and the second image data are different, a different area is extracted, the extracted area is erased from the first image data, and the erased first image data is output. Document reading method characterized the steps of: selecting as an image data, in that it consists of.