JPH10229484A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the output of wasteful image data by deciding whether a blank sheet original exists based on the read image data and deleting the image data, when the blank sheet original is confirmed. SOLUTION: If the original read at a reading part 2 is decided to be a blank sheet by a blank sheet decision part 11, a deletion part 12 deletes the image data on the original and does not output them. The part 11 counts the black pixels of the image data (1), counts the black pixels on each read line (2), when the number of counted black pixels is smaller than the prescribed value, decides the relevant line as a white line, when the number of black pixels counted on each line is smaller than the prescribed value, and decides the relevant image data as a blank sheet when the total number of white lines is larger than the prescribed value with which the original is decided as a blank sheet and also the code value of encoded image data is smaller than the prescribed value (3) respectively.

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 applied to a scanner, a copying machine, a facsimile apparatus and the like, and more particularly to an image reading apparatus having a double-sided mode for reading images on both sides of a document.

[0002]

2. Description of the Related Art Conventionally, an image reading apparatus applied to a scanner, a copying machine, a facsimile machine, etc., has a single-sided mode for reading a single-sided image of a document fed one by one and a double-sided image for a document. 2. Description of the Related Art An image reading apparatus having a duplex mode for reading is known. In a copying machine to which this type of image reading device is applied, an image read in one-sided mode by the image reading device is copied to one side of a transfer sheet in a normal mode (single-sided to one-sided mode), and an image read in one-sided mode by the image reading device. A single-sided → double-sided mode, a double-sided → double-sided mode, a double-sided → single-sided mode, etc. are provided for sequentially copying originals on both sides of a transfer sheet.

[0003]

However, in a conventional image reading apparatus having a double-sided reading mode, one of a single-sided and a double-sided mode is selected. When reading images of a plurality of documents in which a document having an image formed on one side and a double-sided document having images formed on both sides are mixed, the duplex mode is selected. In this case, the back side of the one-sided document is output as a blank sheet. Therefore, for example, when the double-sided to single-sided mode is selected in the copying machine, useless paper is output. Further, in a conventional image reading apparatus having a double-sided reading mode, it has not been applied to a facsimile apparatus. 2. Description of the Related Art In a composite facsimile apparatus having the function of a copying machine, a mechanism for reversing a document to read both sides of the document is provided in a so-called automatic document feeder. Since this automatic document feeder generally supports a large number of sizes, the document feed path is wasted, and it takes time from reading an image on one side (front) of the document to reading an image on the back. Would.

[0004]

The present invention employs the following structure to solve the above problems. <Configuration 1> A reading unit that reads an image of a document, a blank sheet determination unit that determines whether the document is blank based on image data read by the reading unit, and a case where the document is determined to be blank by the blank page determination unit An image reading device comprising: a deletion unit configured to delete image data read by the reading unit.

<Structure 2> In structure 1, the blank page determination unit counts the number of black pixels of the image data read by the reading unit, and if the counted number of black pixels is smaller than the predetermined number of pixels, the blank page determination unit An image reading apparatus, wherein the image reading apparatus determines that the sheet is blank.

<Structure 3> In Structure 1, the blank sheet determination unit counts the number of black pixels for each line read by the reading unit, and if the counted number of black pixels is smaller than a predetermined number of pixels, the blank sheet determination unit is determined. The black pixel number determination unit that determines the line to be a white line, and counts the number of lines determined to be white lines by the black pixel number determination unit, and when the counted white line number exceeds a predetermined white line number, An image reading apparatus comprising: a white line number determining unit that determines that a document is a blank sheet.

<Structure 4> In the structure 1, a coding section for coding an image read by the reading section is provided, and the blank sheet determining section sets the code amount of the image data coded by the coding section to a predetermined value. An image reading apparatus characterized in that a document is determined to be blank when the code amount is smaller than the code amount.

<Structure 5> In the structure 1, a coding section for coding an image read by the reading section is provided, and the blank sheet determination section detects a code amount for each line coded by the coding section. If the detected code amount is smaller than the predetermined code amount, the line code amount determination unit that determines the corresponding line as a white line, and counts the number of lines determined as white lines by the line code amount determination unit. An image reading apparatus comprising: a white line number determination unit that determines that a document is blank when the counted white line number exceeds a predetermined white line number.

<Structure 6> In one of the first to fifth aspects, when one side of the original is called a single side and the other side of the original is called a back side, a single-sided mode for reading an image on one side of the original And a reading mode selection unit for selecting any one of a two-sided mode for reading images on both sides of the document, and when the two-sided mode is selected by the reading mode selection unit, the blank page determination unit is read by the reading unit. An image reading apparatus for performing a blank sheet determination process on an image on the back side of an image of a document.

<Arrangement 7> An image reading apparatus according to any one of Arrangements 1 to 5, further comprising a determination mode selection section for selecting whether or not to make a determination by the blank sheet determination section.

<Structure 8> A reading section for reading an image of a document passing through a predetermined reading position, and a reading section provided opposite to the reading section to carry the fed document to the reading position, and the reading section reads one side of the document. A first transport unit for unloading the original having the read image, a second transport unit for loading and unloading the original unloaded by the first transport unit, and a second transport unit for unloading the original to the discharge stacker by the second transport unit. A first transport path, a second transport path for reversing the original by the second transport section, and carrying out the original to an outlet of the first transport section, a transport path switching member for switching the first and second transport paths, and one of the originals A reading mode selection unit that selects one of a single-sided mode for reading an image on one side of the document and a double-sided mode for reading an image on both sides of the document, when the surface is called one side and the other side of the document is called the back side; Read by the reading unit A mirror image correcting unit for inverting the in-data and correcting the mirror image, wherein the transport path switching member switches to the first transport path when the single-side mode is selected by the reading mode selecting unit, and sets the duplex mode by the reading mode selecting unit. If selected, switch to the second transport path, and if the duplex mode is selected by the reading mode selection unit, the first transport unit, after discharging the original to the second transport unit, reverses the transport direction of the original, The document conveyed by the second conveyance section through the second conveyance path is carried into the reading position through the carry-out port, the document on which the image on the back side of the document is read by the reading section is carried out, and the mirror image correction section is read by the reading section. An image reading apparatus for performing mirror image correction of image data on the back side of image data of a given document.

<Structure 9> A reading section for reading an image of a document passing through a predetermined reading position, and a reading section provided opposite to the reading section for loading the fed document into the reading position and reading the image by the reading section. A first transport unit that transports the received original,
A second transport unit that is provided on the upstream side of the transport path of the document in the transport unit and transports the document on the transport path to the first transport unit;
A first transport path for transporting the original to the discharge stacker by the transport section, and a second transport section in which the original is inverted by the first transport section and the leading end of the inverted document is located on the upstream side of the original transport path. When returning a second transport path, a transport path switching member for switching between the first and second transport paths, and one side of the document as one side and the other side of the document as a back side,
A reading mode selection unit that selects one of a one-sided mode for reading an image on one side of a document and a two-sided mode for reading images on both sides of the document, and a mirror image correction unit that inverts line data read by the reading unit to correct a mirror image The transport path switching member switches to the first transport path when the single-sided mode is selected by the reading mode selection unit, and when a document is newly fed when the duplex mode is selected by the mode selection unit. When the original is returned by the first transport unit to the second transport unit via the second transport route, the first transport unit is switched to the second transport route, and the second transport unit is switched to the second transport route by the first transport unit. The original returned through the transport path is transported again to the first transport unit, and the mirror image correction unit performs mirror image correction of the back side image data among the image data of the original read by the reading unit. Image reading apparatus according to.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 <Configuration> FIG. 1 is a system configuration diagram of a facsimile apparatus to which an image reading apparatus of Embodiment 1 according to the present invention is applied. As shown in FIG. 1, the facsimile apparatus includes a CPU 1, a reading unit 2, an image processing unit 3, a line memory 4, an image memory 5,
Operation display unit 6, encoding / decoding unit 7, modem 8, NCU 9
And a printer 10.

The CPU 1 has a ROM and a RAM (not shown) therein, and controls the entire apparatus based on a control program stored in the ROM and control data stored in the RAM. The reading unit 2 includes an illumination unit (not shown) and an optical unit having a one-dimensional CCD image sensor, and optically reads an image of a transmission document.

The image processing section 3 binarizes the image signal read by the reading section 2 into white data or black data according to a preset slice level. The binarized image data is temporarily stored in the line memory 4 and further stored in the image memory 5. Further, the image processing unit 3
It has a blank sheet determination unit 11, a deletion unit 12, and a mirror image correction unit 13. The blank sheet determination unit 11 determines whether or not the document read by the reading unit 2 is blank. As shown in FIG. 2, the black pixel number counting unit 21 and the black pixel number determination unit 2
2

FIG. 2 is a block diagram showing the configuration of the blank page judging section 11 shown in FIG. Black pixel count section 21
Counts black pixels of one page of the document read by the reading unit 2. When the number of black pixels of one page of the document counted by the black pixel number counting unit 21 is smaller than the predetermined number of black pixels, the black pixel number determination unit 22 determines that the document is blank.

Here, it is not preferable to set the predetermined value to "0". This is because there is an influence of noise when reading the original. Further, there is also an influence such as a shift of a reading range due to the oblique feeding of the document. The predetermined value is preferably about 0.1% of the total number of pixels of the document. For example, if the original is A4 size (210 mm × 297
mm), the reading condition of the reading unit 2 is 8 pixels / mm in main scanning,
In the case of sub-scanning at 7.7 lines / mm, the predetermined value is desirably about 3800 pixels, which is about 0.1% of the number of pixels per page (about 3.8 million pixels). In this case, the black pixel number counting unit 21
Requires a counter of about 12 bits.

Returning to FIG. 1, the deletion unit 12 is a blank page determination unit 1.
If it is determined that the original read by the reading unit 2 is blank, the image data of the original is deleted. The mirror image correction unit 13 reads line data read by the reading unit 2 and written in the line memory 4 in ascending order in descending order, and inverts the left and right sides of the document read by the reading unit 2. The image memory 5 is a transmission / reception buffer memory, and temporarily stores communication information including image data. The image memory 5 also temporarily stores communication information at the time of so-called memory transmission / reception.

The operation display unit 6 inputs the operation of the operator and displays status information of the apparatus. Further, the operation display unit 6 includes a reading mode selection unit 14 and a determination mode selection unit 15. The reading mode selection unit 14 selects one of a single-sided mode for reading an image on one side of a document and a double-sided mode for reading both sides of a document. Normally (initial state), the single-sided mode is set, and the double-sided mode is selected on a menu screen of a liquid crystal touch panel, for example.

The determination mode selection unit 15 includes a blank page determination unit 11
Or not to perform the determination operation based on. The determination mode is set to the off state when the one-sided mode is selected by the reading mode selection unit 14, and the reading mode selection unit 1
When the double-sided mode is selected in step S <b> 4, the setting is made so that the blank image of the back side image read by the reading unit 2 is determined. The determination mode can be switched on the menu screen of the liquid crystal touch panel between blank page determination in the single-sided mode, blank page determination of images on both sides in the duplex mode, and no blank page determination in the duplex mode.

The encoding / decoding section 7 has an MH encoding method (Mo
dified Huffman coding), MR coding method (Modified
READ coding), MMR coding method (Modified MR codi
ng) and the like, and encodes the image data, and decodes the encoded image data. The modem 8 modulates a transmission signal and demodulates a reception signal. The modem 8 exchanges control signals with the facsimile machine of the other party to execute a communication procedure. NCU (Network
A control unit (network control device) 9 controls connection and disconnection of a call with a destination facsimile device. Printer 10
Prints out a management report such as a received manuscript and a transmission report.

FIG. 3 is a sectional view of a main part of an image reading apparatus applied to the facsimile apparatus shown in FIG. As shown in FIG. 3, the document is fed one by one through the guides 41 and 42. The transport path switching claw 35 switches the document transport path by being located on either the first feed roller 31 side shown by a solid line or the guide 42 side shown by a broken line in the drawing. When the one-side mode is selected by the reading mode selection unit 14, the transport path switching claw 35 is always located on the first feed roller 31 side. On the other hand, the reading mode selection unit 1
4, when the duplex mode is selected, the transport path switching claw 35 is set to the first feed roller 31 when reading the one-sided image.
Side, and switches to the guide 42 side when reading the back side image.

Below the reading section 2, a first feed roller 31 is provided. The first feed roller 31 rotates in the F (forward) direction and the R (reverse) direction in the drawing to convey the document. When the single-sided mode is selected by the reading mode selection unit 14, the first feed roller 31
Rotates only in the F direction, carries in the original fed through between the guides 41 and 42, and unwinds the original whose image on one side has been read by the reading unit 2 to the second feed roller 32 along the guides 43 and 44. I do. On the other hand, if the duplex mode is selected by the reading mode
After unloading the original on which the image on one side has been read by R,
Reverse direction.

The second feed roller 32 rotates in the direction F in the drawing, and carries in and out the original carried out by the first feed roller 31. The transport path switching claw 36 switches the transport path of the document. Transport path switching claw 36
In the figure, the document feed path is switched to one of the side of the second feed roller 32 indicated by the solid line and the side of the guide 44 indicated by the broken line. When the one-sided mode is selected by the reading mode selection unit 14, the transport path switching claw 36
Are always located on the second feed roller 32 side. on the other hand,
When the double-sided mode is selected by the reading mode selection unit 14, the mode is switched to the second feed roller 32 side when reading a single-sided image, and is switched to the guide 44 side when reading a back side image.

The guides 41, 42, 43, and 44 correspond to the first feed roller 31, the second Ford roller 32, the transport path switching claw 35 and the transport path switching claw 36, respectively.
1 is formed. Guide 4
5 and 46, the first feed roller 31, the second Ford roller 32, the transport path switching claw 35, and the transport path switching claw 36 form a transport path indicated by a dashed arrow.

When the single-sided mode is selected by the reading mode selecting section 14, the original fed through the guides 41 and 42 is transported through the transport path by the first and second feed rollers and discharged to the stacker 37. You. At this time, the reading unit 2 reads an image on one side of the document passing through the transport path 111.

On the other hand, when the double-sided mode is selected by the reading mode selection unit 14, the original from which an image on one side of the original is similarly read is carried into the transport path 112 along the guide 45 by the second feed roller 32. The sheet is then turned over, and further conveyed by the first feed roller 31 rotating in the R direction and discharged to the stacker 38. At this time, the reading unit 2 reads an image on the back surface of the document passing through the transport path 112.

The image data on the back side in the double-sided mode is read from the direction opposite to the image data on one side in the main scanning direction. Therefore, the mirror image correction unit 13 of the image processing unit 3 reverses the left and right image data of the back side image data to perform mirror image correction.

The document detection sensor 33 and the document detection sensor 34 are sensors for detecting the presence or absence of a document, and control reading start timing of one side and the back side of the reading unit 2, respectively. Also, the first feed roller 31
The rotation direction is switched to the R direction and the F direction after a predetermined time after the reading of the single-sided and back-side images by the reading unit 2, respectively. Similarly, the transport path switching claw 35 is switched at a predetermined timing.

<Operation> The image reading operation of the facsimile apparatus shown in FIGS.

FIG. 4 is a flow chart showing the image reading operation of the facsimile apparatus when the double-sided mode is selected by the reading mode selecting section 14. Here, the blank sheet determination unit 1
Reference numeral 1 is assumed to be set so as to perform blank page determination on the image on the back surface read by the reading unit 2. The transport path switching claw 36 is located on the guide 44 side, and the transport path switching claw 35 is located on the first feed roller 31 side.

First, when the first document is fed (step S1), the document is carried into the reading position of the reading unit 2 by the first feed roller 31 rotating in the F direction, and is read.
The image on one side is read by the first feed roller 3
The sheet is conveyed from 1 to the second feed roller 32 (step S2).

Next, the transport path switching claw 35 is
Side, and the first feed roller 31 is reversely rotated in the R direction (step S3). Next, the document is reversed by the second feed roller 32 along the guide 45, and is further conveyed to the first feed roller 31 along the guide 46 (step S4). Next, the original is carried into the reading position of the reading unit 2 by the first feed roller 31 rotating in the R direction, and the image on the back surface is read by the reading unit 2 (step S5).

Next, the image data of the back surface read by the reading unit 2 is horizontally inverted by the mirror image correcting unit 13 to perform mirror image correction (step S6), and the blank page determining unit 11 determines whether the original is blank. Is performed (step S7).
If the document is determined to be blank, the deletion unit 12
Deletes the image data (step S8). On the other hand, if it is determined that the document is not blank, it is processed as valid image data.

Next, the original is discharged to the stacker 38 between the guides 47 and 48 (step S9). Next, the transport path switching claw 35 is switched to the first feed roller 31 side, and the first feed roller 31 is switched so as to be rotatable in the F direction (step S10).
Next, when there is a next original (step S11, Y
ES), and return to step S1. On the other hand, if there is no next original (step S11, NO), the process ends.

FIG. 5 is a flowchart showing the blank sheet determination operation in step S7 in FIG. First, the number of black pixels for one page of the document is counted by the black pixel number counting unit 21 (step S21). Next, the black pixel number determination unit 22
Is compared with a predetermined value (step S22). Here, when the counted number of black pixels is smaller than a predetermined value, it is determined that the document is a blank document,
A signal indicating that the image data is to be deleted is output to the deleting unit 12 (step S23). On the other hand, when the counted number of black pixels is equal to or more than the predetermined value, it is determined that the document is not a blank document, and the process ends.

<Effects> As described above, according to the specific example 1, when the blank sheet determination section 11 determines that the original read by the reading section 2 is blank, the deletion section 12 deletes the image data. Therefore, it is possible to prevent the output of blank image data. For example, in the case of a facsimile machine, unnecessary image information need not be transmitted, and in the case of a copying machine, useless paper output can be prevented.

Further, the black pixel number counting section 21
The number of black pixels of the image data read by the reading unit 2 is counted, and the document is determined as blank by the black pixel number determination unit 22 when the counted number of black pixels is smaller than a predetermined number of pixels. Therefore, it is possible to easily determine whether or not the document read by the reading unit 2 is a blank sheet.

Further, when the double-sided mode is selected by the reading mode selection unit 14, the blank page determination unit 11 performs a determination process on the back side image of the original image read by the reading unit 2. Therefore, when the duplex mode is selected, image data having a blank back surface can be reliably deleted. In particular, the present invention is effective when reading images of a plurality of documents in which a document having an image formed on one side and a double-sided document having images formed on both sides are mixed. In addition, since whether or not the determination by the blank page determination unit 11 is performed is selected by the determination mode selection unit 15, blank image data can be deleted or output without deletion as needed.

Further, when the double-sided mode is selected by the reading mode selection unit 14, the original on which one side of the image has been read by the reading unit 2 is reversed by the second feed roller 32 along the guide 45, and is rotated in the R direction. The original is carried out by the first feed roller 31 and the image on the back surface is read by the reading unit 2. The mirror image correction unit 13 is configured to invert the left and right of the image data on the back surface to perform the mirror image correction. For this reason, the conveyance path from reading the image on one side of the document to reading the document on the back side can be shortened, and the image on both sides of the document can be continuously read. Can be. In particular, it is suitable for an image reading apparatus having a fixed document size.

In the first embodiment, the main part of the image reading apparatus is configured as shown in FIG. 3, but the image reading apparatus may be configured as shown in FIGS. 6 and 7. FIG. 6 shows FIG.
13 is a diagram showing a modification of the image reading device shown in FIG. FIG.
As shown in FIG. 3, in the image reading apparatus, the positional relationship between the reading section 2 and the first and second feed rollers 33 and 34 of the image reading apparatus shown in FIG.

Guides 51, 52, 53 and 54, first
The feed roller 31, the second feed roller 32, the transport path switching claw 35, and the transport path switching claw 36 form a transport path 113 for reading a one-sided image. The guides 55, 56, 57 and 58, the first feed roller 3
The first and second feed rollers 32, the transport path switching claw 35, and the transport path switching claw 36 form a transport path 114 for reading the back surface image.

FIG. 7 is a view showing a modification of the image reading apparatus shown in FIG. As shown in FIG. 7, in the image reading apparatus, the transport path in the single-sided mode is extended, and the stacker 37 in the single-sided mode and the double-sided mode is shared.

Guides 61, 62, 63 and 64, first
The feed roller 31, the second feed roller 33, the transport path switching claw 35, and the transport path switching claw 36 form a transport path 115 when reading a one-sided image. Also, guides 65, 66, 67 and 68, first feed roller 3
The first and second feed rollers 33, the transport path switching claw 35, and the transport path switching claw 36 form a transport path 116 when reading the back surface image. The transport roller 69 transports the original conveyed by the second Ford roller 34 to the stacker 37 in the one-sided mode.

The image reading apparatus shown in FIGS. 6 and 7 operates in accordance with the flow charts shown in FIGS. 4 and 5 in the same manner as the image reading apparatus shown in FIG.

<< Embodiment 2 >> FIG. 8 shows Embodiment 2 according to the present invention.
3 is a cross-sectional view of a main part of the image reading device of FIG. As shown in FIG. 8, the image reading apparatus is provided opposite to the reading unit 2, and is provided with a feed roller 70 that conveys a document fed along a guide 71, and is provided upstream of the document with the feed roller 70. And a transport roller 75 for transporting the document along the guide 71. When the one-sided mode is selected by the reading mode selection unit 14, the document fed along the guide 71 passes through the transport path formed by the guides 71 and 72, the feed roller 70, and the transport path switching claw 117.
Through the stacker 37. At this time, the reading unit 2 reads an image on one side. The transport path switching claw 36 is located on the feed roller 70 side.

The guides 73 and 74, the feed roller 70, and the transport path switching claw 36 form a transport path 118 for reading the back side image. Reading mode selector 1
When the double-sided mode is selected by 4, the transport path switching claw 36 switches to the lower guide 72 side when reading one-sided image, and the original is carried into the transport path 118 by the feed roller 70.

The document conveyed after being inverted along the guides 73 and 74 by the feed roller 70 is further conveyed along the guide 71 such that the leading end of the document is on the feeding section 31 side. This original is read by the reading roller 2 by the transport roller 75.
And the reading unit 2 reads an image on the back surface. At this time, the transport path switching claw 36 is switched to the guide 72 side, and the document is discharged to the stacker 37.

As described above, the image reading apparatus of the first embodiment reverses the original conveyed by the first feed roller 31 by the second feed roller 32, while the image reading apparatus of the second embodiment Since the apparatus is configured to be inverted by the roller 70, the size of the apparatus can be reduced. In addition, the feed roller need only be rotated in the F direction to facilitate control. Therefore, the device cost can be reduced. The image on the back side of the document read by the reading unit 2 is not only in the main scanning direction but also in the sub-scanning direction. Therefore, for example, when buffering the image memory 4, it is preferable to provide a means for reading out a line for one page in a last-in first-out manner and performing mirror image correction in the vertical direction.

<< Third Specific Example >> Next, a modified example of the blank sheet determination section 11 shown in FIG. 2 will be described. FIG. 9 is a blank sheet determination unit 1 of FIG.
It is a figure which shows the modification of Example 1. As shown in FIG. 9, the blank sheet determination unit 80 includes a line black pixel number counting unit 81, a line black pixel number determination unit 82, a white line number counting unit 83, and a white line number determination unit 84.

The line black pixel number counting section 81 counts the number of black pixels of image data read by the reading section 2 for each line. The line black pixel number determination section 82 compares the number of black pixels for one line counted by the line black pixel number counting section 81 with a predetermined number of black pixels, and determines the counted number of black pixels for one line. Is smaller than the number of black pixels, the line is determined as a white line. The white line number counting unit 83 counts the number of lines determined as white lines by the line black pixel number determination unit 82. When the number of white lines counted by the line black pixel number determination unit 82 exceeds a predetermined number of lines, the white line number determination unit 84
The corresponding document is determined to be blank.

While the blank page determination unit 11 shown in FIG. 2 counts the number of black pixels in the total number of images of the original, FIG.
The blank sheet determination section 11 counts the number of lines determined to be white lines to determine whether or not the document is blank. in this case,
Since it is not necessary to count the total number of pixels of the document, the speed of the determination process can be increased. The predetermined value is, for example, the number of pixels in one line (about 1700 pixels) when the document is A4 size and the reading condition of the reading unit 2 is 8 pixels / mm in main scanning and 7.7 lines / mm in sub-scanning. Of about 0.1% and 1.7 pixels are desirable, and about several pixels are desirable even if errors are considered. Therefore, the line black pixel number counting unit 8
Each of the counters of the 1 and white line number counting section 83 may be a counter of about 3 to 4 bits, and may have a smaller capacity than the black pixel number counting section 21 of FIG.

FIG. 10 is a diagram showing a modification of the blank page judging section 11 of FIG. As shown in FIG.
Has a code amount detection unit 91 and a code amount determination unit 92. The code amount detection unit 91 detects the code amount of the image data for one page of the document encoded by the encoding / decoding unit 7 shown in FIG. The code amount determination unit 92 includes a code amount detection unit 91
Is compared with a predetermined value, and if the detected code amount is smaller than the predetermined value, the original is determined to be blank.

In general, in various coding methods, the compression efficiency tends to be higher as the spatial frequency of the image is lower. When the document is blank, the code amount becomes extremely small. For example, the MH method applied to a facsimile apparatus encodes white / black run lengths, so that this point appears remarkably. Also, images with black pixels on the entire surface are extremely rare. As described above, the blank page can be determined by detecting the code amount of the existing encoding / decoding section 7.
Can be easily configured.

FIG. 11 is also a diagram showing a modification of the blank sheet judging section 11 of FIG. As shown in FIG.
Is a line code amount detection unit 101, a line code amount determination unit 1
02, a white line number counting unit 103 and a white line number determination unit 104. Line code amount detection unit 101, FIG.
The code amount of the image data for each line of the document encoded by the encoding / decoding unit 7 shown in FIG. The line code amount determination unit 102 compares the code amount detected by the line code amount detection unit 101 with a predetermined value. If the detected code amount of one line is smaller than the predetermined value, the line is determined as a white line. judge. The white line number counting unit 103
The number of lines determined as white lines by the line code amount determination unit 102 is counted. When the number of white lines counted by the white line number counting unit 103 exceeds a predetermined number of lines, the white line number determination unit 104 determines that the corresponding document is blank.

As described above, since it is not necessary to count the entire code amount of the document, the determination process can be sped up. Also, for example, if the original is A4 size and the reading conditions of the reading unit 2 are encoded at 8 pixels / mm in the main scanning,
The code amount of one line of all white pixels (about 1700 pixels) is about 17 bits. In this case, the predetermined value is desirably about 20 bits.

In each of the above specific examples, the means for transporting the document is constituted by the first and second feed rollers 31, 32 or the feed roller 70, but these are not limited to the rollers. You may comprise by a conveyance belt.

Also, when the determination processing is performed by the blank paper determination unit 11 of FIG. 1, when the image data is deleted by the determination result generation unit that generates the information indicating the determination result, or when the deletion unit 12 deletes the image data, the blank document is deleted. It is preferable to provide a deletion information generation unit that generates information indicating that the image data has been deleted, display the information on the operation display unit 6, or output the information as a report by the printer 10. The processing result is reliably transmitted to the operator.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a facsimile apparatus to which an image reading device according to a first embodiment of the present invention is applied.

FIG. 2 is a block diagram illustrating a configuration of a blank sheet determination unit 11 illustrated in FIG.

FIG. 3 is a sectional view of a main part of an image reading apparatus applied to the facsimile apparatus shown in FIG.

FIG. 4 is a flowchart illustrating an image reading operation of the facsimile apparatus when the duplex mode is selected.

FIG. 5 is a diagram illustrating an operation of a blank sheet determination unit 11 illustrated in FIG. 4;

FIG. 6 is a diagram showing a modification of the facsimile apparatus of the first embodiment shown in FIG. 3;

FIG. 7 is a diagram showing a modification of the facsimile apparatus of the first embodiment shown in FIG.

FIG. 8 is a sectional view of a main part of an image reading apparatus according to a second embodiment of the invention.

FIG. 9 is a diagram illustrating a modification of the blank page determination unit 11 illustrated in FIG. 2;

FIG. 10 is a diagram illustrating a modification of the blank page determination unit 11 illustrated in FIG. 2;

FIG. 11 is a diagram illustrating a modification of the blank page determination unit 11 illustrated in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CPU 2 Reading part 3 Image processing part 4 Line memory 5 Image memory 6 Operation display part 7 Encoding / decoding 8 Modem 9 NCU 10 Printer 11 Blank sheet judgment part 12 Deletion part 13 Mirror image correction part 14 Reading mode selection part 15 Judgment mode selection Department

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 1/40 G03G 21/00 382 1/41 H04N 1/40 Z

Claims (9)

[Claims] A reading unit configured to read an image of the document, a blank determining unit configured to determine whether the document is blank based on image data read by the reading unit, and determining that the document is blank by the blank determining unit. An image reading device for deleting the image data read by the reading unit when the reading is performed. 2. The image processing apparatus according to claim 1, wherein the blank sheet determination unit counts the number of black pixels of the image data read by the reading unit, and determines that the document is a document when the counted number of black pixels is smaller than a predetermined number of pixels. Is determined to be a blank page. 3. The method according to claim 1, wherein the blank sheet determination unit counts the number of black pixels for each line read by the reading unit, and when the counted number of black pixels is smaller than a predetermined number of pixels, A black pixel number determining unit that determines the corresponding line as a white line, and counts the number of lines determined as white lines by the black pixel number determining unit, and the counted white line number exceeds a predetermined white line number. An image reading apparatus, comprising: a white line number determining unit that determines that a document is a blank sheet. 4. The image processing apparatus according to claim 1, further comprising an encoding unit that encodes the image read by the reading unit, wherein the blank page determination unit determines that the code amount of the image data encoded by the encoding unit is An image reading apparatus characterized in that when the code amount is smaller than a predetermined code amount, the document is determined to be blank. 5. The image processing apparatus according to claim 1, further comprising: an encoding unit that encodes the image read by the reading unit, wherein the blank page determination unit is configured to encode the image read by the encoding unit.
A code amount is detected for each line, and when the detected code amount is smaller than a predetermined code amount, a line code amount determination unit that determines the corresponding line as a white line, and a white line by the line code amount determination unit. An image reading apparatus, comprising: a white line number determining unit that counts the determined number of lines and determines that the document is blank when the counted number of white lines exceeds a predetermined number of white lines. 6. A single-sided mode for reading an image on one side of a document, wherein one side of the document is referred to as one side and the other side of the document is referred to as a back side. A reading mode selection unit that selects any one of a two-sided mode for reading a two-sided image. When the two-sided mode is selected by the reading mode selection unit, the blank sheet determination unit is read by the reading unit. An image reading apparatus for performing a blank page determination process on an image on the back side of the image of the original. 7. The image reading apparatus according to claim 1, further comprising a determination mode selection unit that selects whether or not to perform the determination by the blank page determination unit. 8. A reading section for reading an image of a document passing through a predetermined reading position, provided opposite to the reading section, loading the fed document into the reading position, and reading the document by the reading section. A first transport unit for unloading the original having the image read on one side thereof, a second transport unit for loading and unloading the original unloaded by the first transport unit, and an original stacker for discharging the original by the second transport unit A first transport path for unloading, a second transport path for reversing a document by the second transport section and transporting the original to an outlet of the first transport section, and a transport path switching member for switching between the first and second transport paths When one side of the document is called one side and the other side of the document is called the back side, select either one side mode to read one side image of the document or two side mode to read both sides image of the document Reading mode selection section A mirror image correcting unit for inverting the line data read by the reading unit and correcting the mirror image, wherein the transport path switching member is configured to perform the first transport path when the one-sided mode is selected by the reading mode selecting unit. To the second transport path when the duplex mode is selected by the reading mode selecting unit. The first transport unit switches to the second transport when the duplex mode is selected by the reading mode selecting unit. After the document is carried out to the section, the document carrying direction is reversed, the document carried through the second carrying path by the second carrying section is carried into the reading position through the carry-out port, and the document is carried out by the reading section. Unloading the document from which the backside image has been read, the mirror image correction unit performs mirror image correction of the backside image data among the image data of the document read by the reading unit. An image reading apparatus characterized by the above-mentioned. 9. A reading section for reading an image of a document passing a predetermined reading position, and a reading section provided opposite to the reading section, for loading a fed document into the reading position, and forming an image by the reading section. A first transport unit that unloads the read original, and a second transport unit that is provided upstream of the first transport unit on the original transport path and transports the original on the transport path to the first transport unit. A first transport path for transporting the original to the discharge stacker by the first transport section; and a first transport section for inverting the original so that the leading end of the inverted document is upstream of the original transport path. , The second
A second transport path for returning to the transport section, a transport path switching member for switching between the first and second transport paths, and when one side of the document is called one side and the other side of the document is called a back side, A reading mode selection unit for selecting one of a single-sided mode for reading an image on one side of a document and a double-sided mode for reading images on both sides of a document; and a mirror image correction unit for inverting line data read by the reading unit and correcting the mirror image The transport path switching member switches to the first transport path when the one-sided mode is selected by the reading mode selection unit, and newly outputs the original when the two-sided mode is selected by the mode selection unit. When the document is fed, it is switched to the second transport path, and when the original is returned to the second transport section through the second transport path by the first transport section, the original is switched to the first transport path. The second transport unit transports the document returned by the first transport unit through the second transport path to the first transport unit again, and the mirror image correction unit reads the document read by the reading unit. An image reading device for performing mirror image correction of image data on the back surface of the image data.