JPH06141126A - Picture reader - Google Patents

Abstract

PURPOSE:To output desired read information corresponding to picture information even when an original is set while the front/rear side is set wrong when an original having picture information only on one side is read with respect to th picture reader used for a picture entry means such as a copying machine. CONSTITUTION:The picture reader IR provided with an automatic original carrying device 500 which carries plural originals one by one each and sets them to a read position and turns over the front/rear side of the original as required is provided with a means discriminating whether or not a read object face of the original is a white face and a means controlling the automatic original carrying device so as to turn over the front/rear side of the original.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus used as an image inputting means for a copying machine, a facsimile machine, an image editing system centering on a computer or a word processor, and a filing system.

[0002]

2. Description of the Related Art Conventionally, an automatic double sided document feeder (ADFR) has been used as an auxiliary device of an image reading device.

The ADFR is necessary in addition to the basic function (ADF function) of sequentially transporting a plurality of originals set in a document stacker one by one, setting them at the reading position, and ejecting them after the reading is completed. Accordingly, it has a function of reversing the front and back of the original and setting the reversed original at the reading position again.

That is, the ADFR has an ADF function that is particularly useful when reading a large number of originals, and an automatic original feeding function that automatically reverses the front and back of originals when reading a double-sided original having image information on both sides. It is a device.

In the image reading apparatus equipped with ADFR, when a single-sided original having original information on only one side is read, the original is discharged immediately after the reading on one side is completed.
When reading a two-sided original, the original is automatically turned over after the first side (front side) is read, and then the second side is read.
The front side (back side) is read.

[0006]

DISCLOSURE OF THE INVENTION In ADFR,
The structure of the transport path defines the orientation of the front and back sides of the document set on the document stacker. That is, of the front and back surfaces of the document set at the reading position, the surface to be read facing the scanner has an ADFR of a type corresponding to the upper surface on the document stacker and an ADFR of a type corresponding to the lower surface on the document stacker. There is.

Therefore, for example, when the original is a single-sided original, the operator selects the original according to the type of ADFR so that the surface having the image information (hereinafter referred to as the image existing surface) is the upper side or the lower side. It is necessary to set the document stacker correctly.

However, the operator may mistakenly set the front and back sides to set a single-sided original. In such a case, the conventional image reading apparatus has a problem that a surface without image information (hereinafter referred to as a blank surface) is read, and the document is discharged without reading the image existing surface. It was

For this reason, the operator must set the original again and instruct to read it again. Also,
If the image reading device is, for example, an image input unit of a copying machine, a blank sheet is copied based on the read information, and the paper is wastefully consumed. Especially when the number of documents is large, a large amount of paper is wasted.

In view of such a problem, the present invention, when reading a document having image information on only one side, sets the desired read information corresponding to the image information even when the document is set in the wrong orientation. It is an object of the present invention to provide an image reading device capable of outputting.

[0011]

In order to solve the above-mentioned problems, an apparatus according to the present invention conveys a plurality of originals one by one in order and places them at a reading position, and if necessary, In an image reading apparatus equipped with an automatic document feeder configured to be able to reverse the front and back sides, a means for determining whether or not a reading target surface of a document is a blank sheet surface and a reading target surface is a blank sheet surface. And a means for controlling the automatic document feeder so as to reverse the front and back of the document when it is pressed.

[0012]

With respect to the document placed at the reading position, it is determined whether the one surface of the document to be read facing the reading means is a blank surface or an image existing surface.

When the surface to be read is blank, the automatic document feeder reverses the front and back of the document. This allows
The surface to be read becomes the image existing surface, and the original image information can be read.

[0014]

1 is a sectional front view showing the overall construction of a copying machine 1 having an image reader IR according to the present invention, and FIG. 2 is a perspective view showing the appearance of an automatic double-sided document feeder 500.

The copying machine 1 is a digital copying machine capable of two-color copying, and comprises an image reader IR and a page printer PRT. Image reader IR
The main body of the scanning system 10 is a scanning system 10 for reading a document placed on a platen glass 18 by separating it into two colors, quantization of photoelectric conversion signals output from the scanning system 10, and signal processing according to various image forming modes. An image signal processing unit 20 for performing the above and a memory unit unit 30 for storing the image data corresponding to the document. Then, an automatic double-sided document feeder (ADF) which is an additional device also serving as a document cover on the upper part of the main body
R) 500 is assembled so that it can be opened and closed with its rear end as a fulcrum.

The scanning system 10 is a line scanning type image reading mechanism, and includes a scanner 19 having a document irradiation lamp 11 and a mirror 12, fixed mirrors 13a and 13b, a condenser lens 14, dichroic mirrors 15 and 2. It is composed of one image sensor 16, 17 and a scan motor M2 for driving the scanner 19. The image signal processing section 20 and the memory unit section 30 will be described later.

The ADFR 500 conveys the original set on the original stacker 510 onto the original table glass 18 by a paper feed roller 501, a separation roller 502, a separation pad 503, an intermediate roller 504, a registration roller 505 and a conveyor belt 506. , The document after reading is ejected by the roller 50
Then, the document is discharged onto the document discharge tray 511 by the reference numeral 9. ADF
The R500 includes an original scale 512 and a paper feed sensor SE5.
1, and a discharge sensor SE52 are provided.

For example, when copying a plurality of originals, the operator sets the originals such that the surface (image-existing surface) faces upward as shown in FIG. Each original on the original stacker 510 is pulled out one by one from the lowermost original, and is accurately set at the reading position on the original glass 18 with the front side facing down. Then, in the single-sided original mode, after the reading is completed, the original is conveyed in the left direction in the drawing and is ejected so that the upper surface becomes the front surface. In the case of the double-sided original mode, the original fed to the left after the front side is read is reversed by the reversing roller 507 and returned to the reading position on the platen glass 18, and after the rear side is read. It is sent to the left again and discharged.

The page printer PRT includes a semiconductor laser 6
A developing / transferring system 70A having a print head 60 having light sources 1, 2 and 62, a photosensitive drum 71, two developing devices 73a and 73b, a fixing roller pair 84, and a discharge roller 8.
5, a fixing / discharging system 70B, and a paper transport system 70C having various rollers and a transport belt 83, and a copy image is formed by an electrophotographic process based on the image data transferred from the image reader IR. Form (print).

Below the page printer PRT, there are two paper cassettes 80a, 8a capable of storing several hundreds of papers.
0b is provided. A re-feeding device 600, which is an additional device for completely automating double-sided copying and composite copying, is attached to the side surface of the page printer PRT.

The developing device 73 of the developing / transferring system 70A
a, 73b and various chargers 72a, 72b, 74,
Each of the 75 is independently controllable. Further, the sheet conveyance system 70C has an operation mode in which the sheet is discharged as a blank sheet when the blank side of the original is read.

3 and 4 are block diagrams showing the configuration of the control unit 100 of the copying machine 1. The control unit 100 is mainly composed of six CPUs 101 to 106, and each of these CPs
U101-106 are provided with ROM111-116 which stored the program, respectively, and RAM121-126 used as a work area of program execution. The CPU 103 is provided inside the memory unit section 30.

The CPU 101 controls the operation panel OP (see FIG. 2) provided on the upper surface of the main body of the image reader IR. The CPU 102 is responsible for drive control of the scanning system 10 and control of the image signal processing unit 20.

The CPU 103 controls storage and reading of image information for memory mode copying, and
A blank page detection process specific to the present invention is performed. CPU 104
It controls the entire page printer PRT including the print processing unit 40 that modulates the semiconductor lasers 61 and 62.

The CPU 105 is responsible for the overall timing adjustment of the control unit 100 and the setting of the operation mode of the copying machine 1. Therefore, the CPU 105 is the other CPU 1
Serial communication with 01 to 104, 106 is performed to send and receive commands, reports, and other data required for control.

Then, the CPU 106 is in charge of the conveyance control of the document, and the CP is controlled in accordance with the result of the blank sheet detection by the CPU 103.
According to the instruction given from U105, the ADFR 500 is controlled so as to immediately eject the document whose surface has been read, or to turn the document upside down and reset it to the reading position.

FIG. 5 is a block diagram showing the configuration of the image signal processing section 20. The image signal processing unit 20 includes an A / D conversion unit 21, an image processing unit 22, an image monitor memory 23, and a timing control unit 24 that outputs a synchronization signal for the operation of each of these units.

The A / D converter 21 is provided for each image sensor 1
The photoelectric conversion signals of 6 and 17 are respectively quantized to generate 8-bit (256 gradations) image data. Image processing unit 2
2 is shading correction, MTF correction, gamma correction,
Then, image processing such as scaling processing is performed, the processed image data D2 is output as read information, the color of the pixel of the document is determined, and color data DC2 that is color determination information is output. The image monitor memory 23 is used to store sample data for shading correction.

FIG. 6 is a block diagram showing the configuration of the memory unit section 30. The memory unit section 30 includes an image switching section 301, a binarization processing section 302, a multi-port image memory 304, a code processing section 305 having a compressor 311 and an expander 312, a multi-port code memory 306,
The multi-value processing unit 308, the scaling processing unit 309, and the above-described CPU 103 that controls these units are included, and are configured to compress and store image information in order to reduce the memory capacity. The image memory 304 has a capacity capable of storing image data for two pages read at a resolution of 400 dpi.

The memory unit section 30 is supplied with 1-bit color data DC2 from the image signal processing section 20 together with 8-bit image data D2. These data D2
The DC 2 receives the binarization processing unit 3 via the image switching unit 301.
Sent to 02.

The binarization processing unit 302 converts the multi-valued image data D2 into binary image data within a recoverable range by, for example, the dither method. The image data after binarization is stored in the image memory 30 together with the color data DC2.
4 is once written.

In parallel with this, the CPU 103 executes a blank sheet detection process for determining whether or not the reading target surface of the document is a blank surface based on the image data D2, and the determination result is C
Notify the PU 105.

When the surface to be read is a blank surface, that is, when there is an error in setting the original, the CPU 103 cancels the encoding and compression / expansion described later, and the image memory 3
One page of image information (invalid information corresponding to a blank page) stored in 04 is deleted. As a result, the read information is not output to the page printer PRT, and the blank page is not copied.

Further, in this case, the CPU 105 instructs the CPU 106 to reverse the front and back of the original as described above, and when the completion of the inversion is notified, the CPU 102 scans the same original for the second time. Give instructions. As a result, the original image existing surface is automatically read even if there is an error in the document set, and the operator can obtain the desired copy image without re-doing the document set.

On the other hand, when the surface to be read is the image existing surface, the CPU 103 performs the encoding and compression / expansion control described below as normal processing. CPU10
In accordance with the instruction of No. 3, the code processing unit 305 causes the image memory 3
The image data written in 04 is read and compressed to generate code data (compressed data), which is written in the code memory 306. In addition, the code processing unit 305 stores code data to be printed or image confirmation as the code memory 3.
The image data obtained by reading from 06 and expanding is written in the image memory 304. It should be noted that the compressor 311 and the decompressor 312 are configured to be operable independently of each other and in parallel in order to improve the copying speed, and between these and the code memory 306, data (not shown) D
DMA transfer is performed by the MA controller.

When the image data for one page is reproduced by the decompression, the CPU 103 reads the image data from the image memory 304 and sends it to the multilevel halftoning processor 308. At the time of printing, the multi-value processing unit 308 infers the multi-value to be restored from the dot array of the binary data, and reverses the binary data to the original data, contrary to the binary processing unit 302. Perform the returning process. On the other hand, at the time of image confirmation, since the binary data can be used as it is for displaying the liquid crystal screen of the operation panel OP, the multilevel halftoning processing unit 308 enters the data through state.

The scaling processing unit 309 is a multi-value processing unit 308.
The restored image data is scaled as necessary and sent to the image switching unit 301. The image switching unit 301 outputs the 8-bit image data D3 restored by the multi-value quantization processing unit 308 to the print processing unit 40 at the time of printing, and outputs the binary data to the operation panel unit as the image data D4 at the time of image confirmation.

FIG. 7 is a flowchart of the blank sheet detection process, and FIG. 8 is a diagram showing the density distribution of various originals. Note that FIG.
In (a) to (c), the density distribution is shown by a histogram, and the horizontal axis of each histogram is the image data D.
It has a value of 2.

Here, the image data D2 is 8-bit density data (data proportional to the original density) obtained by the gamma correction by the above-described image signal processing unit 20, and is the lightest pixel (white pixel). The value is “0”, and the value of the darkest pixel (black pixel) is “255”.

Generally, as shown in FIG. 8A, the maximum density level of the background (here, "128" in a white original).
The image data D2 having a value exceeding (approx.) Hardly appears. On the other hand, as shown in FIGS. 8B and 8C, a large number of image data D2 having a value exceeding the maximum density level of the background appear in the text original and the photographic original.

Therefore, one page of image data D2
With respect to, by counting the number of appearances of the image data D2 having a value larger than the maximum density level of the background, it is possible to determine whether the reading target surface of the document is a blank surface.

In FIG. 7, the CPU 103 first sets the maximum density level "128" of the background as the initial value of the count target (# 10). Next, the density level "12
The number of pixels corresponding to "8" is counted, and the ratio of the counted number to the total number of pixels on one page is a constant value (for example, 1%).
If it is larger, the CPU 105 is notified that the surface to be read is the image existing surface (# 11, 12, 16).

On the other hand, if the ratio of the number of counts is smaller than a certain value (less than 1%), the density level to be counted is set to 1
And the pixel number ratio is sequentially checked for each of the density levels “128” to “255” (# 1
2-14).

When the number of pixels corresponding to the final density level "255" is less than 1% of the total number of pixels, the reading target surface of the document currently set at the reading position is a blank surface. That is notified to the CPU 105 (# 1
5) FIGS. 9 to 11 show the CPU 10 that controls the control unit 100.
5 is a flowchart of a document scanning process in a single-sided document mode of No. 5.

When the operator presses the start key 96 on the operation panel OP, the CPU 105 causes the ADFR 50
For the CPU 106 controlled by 0, the document stacker 51
It is instructed to start the document feeding for setting the one-sided document on 0 at the reading position (# 20).

When the document feeding is completed, the CPU 105 sets the magnification, the scan length, and the exposure amount, that is, the document scan mode according to the designation of the print mode such as the variable magnification mode or the character / photo mode and the document size. Do (#
21, 22).

Subsequently, the CPU 105 instructs the CPU 102 to start the document scanning (# 23), and the CPU
The 104 is sequentially instructed to feed a copy sheet of a predetermined size and to drive an image forming unit such as the transfer / developing system 70A (# 24, 25).

After the document scanning is completed, the CPU 105 takes in the result of the blank sheet detection notified from the CPU 103 as described above, and when the surface to be read of the document is not a blank surface, instructs the document to be ejected and jams the document. Set a timer to check for the presence or absence (# 26, 2
7, 28, 33).

On the other hand, when the surface of the original to be read is a blank surface, the CPU 105 first instructs the CPU 106 to invert the front and back of the original as a countermeasure against the erroneous setting of the original, and then, to the CPU 102 after the completion of the inversion. The start of document scanning is instructed, and the document ejection is instructed after the end of document scanning (# 29, 30, 31, 32, 33).

After that, the CPU 105 instructs the CPU 103 and the CPU 104 to start the execution of a predetermined process for printing (# 34). Then, when the document ejection notification is not issued even though the timer set previously has been timed, the CPU 105 executes the document jam processing for instructing the jam display or the like (# 35 to 37).

According to the above-described embodiment, the read information on the white paper surface is erased, so that meaningless copying of the white paper surface is prevented. In the above-described embodiment, when the blank side of the document is read, the sheet conveying system 70C is configured to discharge the sheet as a blank sheet (a state in which the toner image is not transferred) in order to inform the operator of an error in setting the document. The sequence of can be set. In that case, the paper cassettes 80a, 8
It is also possible to store the color paper in one side of 0b and eject the color paper as it is to notify the operator of an error in setting the original. Since the paper used for the notification has not undergone the transfer process, it can be reused without spotted toner adhesion (so-called noise).

[0052]

According to the present invention, when reading a document having image information on only one side, even if the document is set in the wrong orientation, the desired read information corresponding to the image information is output. can do.

[Brief description of drawings]

FIG. 1 is a sectional front view showing an overall configuration of a copying machine having an image reader according to the present invention.

FIG. 2 is a perspective view showing the appearance of an automatic double-sided document feeder.

FIG. 3 is a block diagram showing a configuration of a control unit of the copying machine.

FIG. 4 is a block diagram showing a configuration of a control unit of the copying machine.

5 is a block diagram showing a configuration of an image signal processing unit in FIG.

FIG. 6 is a block diagram showing a configuration of a memory unit section of FIG.

FIG. 7 is a flowchart of a blank sheet detection process.

FIG. 8 is a diagram showing density distributions of various originals.

FIG. 9 is a flowchart of a document scanning process in a single-sided document mode of a CPU that controls a control unit.

FIG. 10 is a flowchart of a document scanning process in a single-sided document mode of a CPU that controls a control unit.

FIG. 11 is a flowchart of a document scanning process in a single-sided document mode of a CPU that controls a control unit.

[Explanation of symbols]

 IR image reader (image reading device) 500 automatic double-sided document feeder (automatic document feeder) 103 CPU (means for discriminating whether or not it is blank) 106 CPU (means for controlling the automatic document feeder)

Claims (1)

[Claims] 1. An image provided with an automatic document feeder configured so that a plurality of documents are sequentially transported one by one and placed at a reading position, and the front and back of the documents can be reversed if necessary. In the reading device, a means for determining whether or not the reading target surface of the document is a blank sheet surface, and the automatic document feeding device for inverting the front and back sides of the document when it is determined that the reading target surface is a blank sheet surface. And a means for controlling the image reading apparatus.