JPH0927888A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a reader to conduct post processing corresponding to an original skewed due to some unknown cause. SOLUTION: Image information of an original D is read by a CCD 16 whose elements are arranged side by side and an image processing section 27 detects a skewed original based on read data. On the occurrence of a skew, a CPU 20 compares a preset skew reference value B with a produced skewed original A and discriminates it to be an excessive skew in the case of A>B, and provides status information denoting a page number where the skew takes place and the amount of skew to an operation display section 33, in which the information content is displayed and post processing is conducted (error processing).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading apparatus applied to a facsimile machine, a copying machine, a scanner for scanning a document, and the like.

[0002]

2. Description of the Related Art In a conventional document reading apparatus, when a document is conveyed to a document reading position, the document may skew (skew) for some reason. Depending on the degree of this skew, a document jam may occur or the document may not be properly read, and therefore some devices are equipped with means for dealing with the generated skew.

[0003]

However, in the above-mentioned conventional apparatus, the degree of skew is judged and post-processing, for example, stop of the reading operation, control of document transportation, document ejection, document re-setting, etc. are performed. That is, the post-processing is not always performed in conformity with the capability of the skew correction function of the document reading device itself or an external device such as a host computer connected to the document reading device. was there.

An object of the present invention is to provide an image reading apparatus in which post-processing operation corresponding to document skew is performed.

[0005]

In order to achieve the above object, the present invention provides a photoelectric conversion element arranged one-dimensionally with respect to an original reading position, and an original read by a read data from the photoelectric conversion element. A means capable of reading the image information and detecting the document skew state and a means for issuing status information and performing a post-processing operation when a skew of a predetermined reference value or more occurs Is characterized by.

A photoelectric conversion element arranged one-dimensionally with respect to the original reading position and means for reading image information of the original and detecting the skewed state of the original by the read data from the photoelectric conversion element. And a means for issuing status information to a connected host computer to perform a post-processing operation when a skew of a predetermined reference value or more occurs.

Further, it is characterized in that the reference value can be arbitrarily set.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a scanner apparatus according to an embodiment of the present invention, in which 1 is a known automatic document feeder (ADF) provided on the upper right side of the apparatus main body 2 and 3 is an ADF 1.
Internal stepping motor for document feeding, 4
Is a document setting table, 5 is a contact glass which is a document reading table provided on the upper surface of the apparatus main body 2, 6 is a document pressing plate which is formed integrally with the ADF 1 and can open and close the surface of the contact glass 5, Reference numeral 7 is a known white reference plate which is provided at the right end of the contact glass 5 below the ADF 1 and is read during shading correction.

A light source (for example, a fluorescent lamp) is provided inside the apparatus main body 1.
A first traveling body 12 including a mirror 10 and a mirror 11, a second traveling body 15 including a pair of mirrors 13 and 14, and photoelectric conversions arranged one-dimensionally in the main scanning direction of document reading. Element (eg CC
D, etc.) 16, a lens 17 for forming an original image from the second traveling body 15 on the photoelectric conversion element 16, and both traveling bodies 12,
A stepping motor 18 for driving 15 is provided.

FIG. 2 is a block diagram showing a control circuit in the scanner device. A CPU (central processing unit) 20 has a motor driver 21 for a stepping motor 3 for feeding a document and a stepping device for driving a traveling body. A motor driver 22 for the motor 18, a driver 23 for the fluorescent lamp 10, a driver 24 for the CCD 16, ROM 25 and RAM 26 which are memory elements,
An image processing unit 27, which will be described in detail later, a scan buffer 28,
A buffer controller 29 that manages input and output of data to and from the scan buffer 28, a line buffer 30 corresponding to scan lines, an interface (I / F) controller 31 that controls an interface with an external device such as a host computer 32, The operation / display unit 33 and the like provided with a key for operation and a display unit for displaying information such as various modes and setting states are connected to exchange control signals and the like.

FIG. 3 is a block diagram showing the arrangement of the image processing section. The image processing section 27 includes an analog video processing section 35 for processing an analog video signal, a shading correction processing section 36, and an image data processing section 37. And binarization processing unit 38
And a timing generator 39 for generating a timing signal.

In the above-mentioned scanner device, as a document reading mode, as shown in FIG. 4, a document is placed on the contact glass 5 and the first traveling body 12 is moved to read the image information of the document. In the fixed reading mode and as shown in FIG. 5, the ADF 1 is used to sequentially feed the documents stacked on the document setting table 4, and the first traveling member is in the fixed state at the reading position of the white reference plate 7 portion. There is an ADF type reading mode for reading the image information of the document at 12.

Next, the basic operation of the scanner device will be described.

In the fixed original reading mode, the original D is set on the surface of the contact glass 5 below the original pressing plate 6,
When the start key is turned on, the CPU 20 operates the fluorescent lamp driver 23 to turn on the fluorescent lamp 10, and the CCD driver
The white reference plate 7 is read by the CCD 16 driven by 24, reference data for shading correction of the image data is obtained by the image processing unit 27, and the reference data is recorded in a memory (not shown) in the image processing unit 27. deep.

Further, the CPU 20 drives the stepping motor 18 for driving the traveling body via the motor driver 22 to move the first traveling body 12 in the sub-scanning direction of the document D. The image information of the document D is read by the CCD 16 when the first traveling body 12 moves. Then, as shown in FIG. 3, the analog video signal a photoelectrically converted by the CCD 16 is digitally converted by the analog video processing unit 35 of the image processing unit 27, and then the shading correction processing unit 36 and the image data processing are performed. Shading correction and various types of image data processing are performed by the unit 37, and binarization processing is performed by the binarization processing unit 38, and the binarized data b is output. Thereafter, the binarized data b is converted into the binary data shown in FIG.
Are sequentially recorded in the scan buffer 28. The data in the scan buffer 28 is output to the external host computer 32 under the control of the I / F controller 31.

In the ADF type reading mode, after the white reference plate 7 is read, the CPU 20 drives the stepping motor 3 for feeding the original document via the motor driver 21, and the original document placed on the original document setting table 4 is driven. Are conveyed one by one toward the document reading position on the contact glass 5.
At this time, the document is conveyed at a constant speed, and the first traveling member
The image information of the document D is read by the CCD 16 with 12 stopped. The analog video signal photoelectrically converted by the CCD 16 is processed in the same manner as in the fixed original reading mode,
The data is sequentially recorded in the scan buffer 28. The data in the scan buffer 28 is output to the host computer 32 or the like under the control of the I / F controller 31.

In the present scanner device, a pixel counter and a line counter are provided in the main scanning direction and the sub-scanning direction, respectively, for reading an original, and the reading point can be indicated by the counter values. As the pixel counter and the line counter, for example, the CPU 20 may be provided with a function corresponding to each counter.

Next, the detection of the position and width of the original will be described.

In order to detect the position and width of the original, it is necessary to detect the edge of the original. For example, a uniform density member 40 having a uniform density as shown in FIG. Is provided, the document size detection position X is set on the uniform density member 40, and the density difference from the document D is detected. Since the uniform density in this case is intended to be separated from the background density of the original to be read, the uniform density is set to a density that can be reliably separated from the background density of the original. Since the standard white document has a density level of OD (optical density) of about 0.1,
It suffices to have a density that can be separated from this density.

FIG. 7A shows an example of density level distribution of the uniform density member. Note that black is described as a high level and white as a low level. Further, for the sake of simplification of description, it is shown that the uniform density member 40 is read by the first running body 12 and the CCD 16 to output a uniform density level, but in reality, there are many density fluctuations. The illustrated position A is the reading start position in the main scanning direction. The position B indicates the main scanning read end position. Further, although the end portion of the uniform density member 40 in the main scanning direction is also illustrated as the position A and the position B, it is not particularly limited.

At the position A, the first pixel of the pixel counter in the main scanning direction is set, and the pixel counts up sequentially. FIG. 7B is an explanatory diagram showing a distribution example of density levels when a document is detected. As can be seen from the figure, the C position indicates the start of the document density distribution in the main scanning direction, and the C position to the D position indicate the document width. The pixel position in the main scanning direction at the C position and the D position digitizes the point position, and the point indicated by this address thereafter indicates the position and width of the document.

The document size detection operation will be described more specifically.

In the ADF type reading mode, as shown in FIG. 6, the document D is conveyed until the document D surely appears at the document size detection position X on the uniform density member 40, and the document width at that time is set to the above-mentioned value. To detect. When this detection is performed, an interrupt is issued to the CPU 20 at that time. When the CPU 20 receives the interrupt signal, it can obtain the document position and its width information by reading the address values of the C position and D position obtained by the document size detection. When the detection process ends, the CPU 20
Moves the first traveling body 12 to the document reading position and also conveys the document D to the document reading position.

The CPU 20 outputs the document size data to the host computer 32 before reading the document data according to the designation of the mode of the document size detection processing, and the host computer 32 specifies the reading area to the scanner device by the document size data. Alternatively, the original is directly read according to the original size data. Then, after sending the read data (image data) to the host computer 32, by sending the size of the document in the main scanning direction and the sub-scanning direction to the host computer 32, the main scanning synchronization with the image data sent to the host computer 32. An image can be reproduced as the obtained image.

Note that the original size detection for reading an original while it is being conveyed cannot detect the trailing edge of the original from the read data, so a detecting means (not shown) for detecting the presence or absence of the original when the original is conveyed. This is performed by detecting the trailing edge of the document based on the detection result of (1).

Next, document detection in the case where the document is skewed as shown in FIG. 8 from the state of FIG. 6 will be described. That is, when the original document is normally conveyed in FIG. 6, the original document D is conveyed until the original document size detection position X appears with certainty, but in order to positively detect the skew, the original document D reaches the original document size detection position X. The detection process is started from before.

In the detection process, an interrupt is generated for the CPU 20 by detecting the original at the original size detection position X, and the original position information and the original width information are provided to the CPU 20 each time this occurs. Write to register. While performing this writing process, the document position information and the document width information at the time of the previous interrupt are taken out from the register, and are compared with the document position information and the document width information at the time of the current interrupt. A more specific description will be given with reference to FIGS.

FIGS. 9A to 9E show changes in the density level detected at the document size detection position X when a skew occurs. In FIG. 9A, the document is still located at the document size detection position X. Has not reached. FIG. 9B shows a detection state at the time when the leading end of the document D reaches the document size detection position X, and from this time, an interrupt is generated to the CPU 20,
At the same time, the document position information and document width information at this time are written in the register. Next, due to the occurrence of the interrupt in FIG. 9 (c),
While writing the document position information and the document width information at this time into the register, the document position information and the document width information in FIG. 9B are read out, and both the information is compared. As a result of comparison, since the document width in the case of FIG.
Determines that the document D is skewed, has not reached the maximum width yet, and is in the process of expanding in width.

Further, when the document D is conveyed, it is shown in FIG.
As shown in FIG. 9E, the CPU 20 is shown in FIGS. 9D and 9E.
It is determined that they are the same when comparing the document width information based on the detection result. That is, the document D is conveyed to the maximum width. The maximum width is due to the document conveyance up to FIG. 9D. The information in FIG. 9E indicates whether the width data of the document D in FIG. 9D is the maximum data. It is used as information to judge. In this way, the data related to the document width is updated while performing the interrupt process of the document detection process, and the maximum data of the document width is found. In this example, the document conveyance distance in FIGS. 9B to 9D is the amount of deviation due to skew.

To actually express the skew amount, the original D
Position information ((X in FIG. 8
1 and Y2)) and the position information ((X2, Y3), (X3, Y3) in FIG. 8) in FIG.

CPU 20 when it is judged to be the maximum data
The above data is collected and the skew data, the document position data, and the document width data are read by the host computer 32 according to the instruction from the host computer 32 before the image data is read.
It is sent to 32 or later. In any case, after the detection is completed, the first traveling body 12 is moved to the document reading position, and the document is also conveyed to the document reading position,
Scan the original image.

In the fixed original reading mode, the original D
Is set on the surface of the contact glass 5 with its side portion in contact with a predetermined size defining portion (abutting with origin), and is pressed against the surface of the contact glass 5 by the document holding plate 6. As described above, the document size needs to be separated from the document as described above. Therefore, the document pressing surface of the document pressing plate 6 has a uniform density that can be reliably separated from the background density of the document. Further, the document size is detected at a position where the leading edge of the document can be reliably determined, and the document width and position for reading the document are set based on the detected data.

That is, since the document D is set in contact with the size defining portion, the first traveling body 12 and CC
The reading with D16 is performed from the origin line of the size regulation section. At that time, since the trailing edge position of the document is detected, it can be determined that the document within the document range is surely present, and the original size of the document is not obstructed by the density of the image data within the document range. The image data on the inside is scanned from the side surface.

Then, while the original is read in the sub-scanning direction at the same reading position, the presence or absence of the original is detected by the density of the original. When the reading of the original document in the sub-scanning direction is completed, the original document density does not exist and the original document holding plate 6 has the same density.
When the change from the original density to the original pressing plate density is detected, an interrupt signal is generated to the CPU 20. C
Upon receiving the interrupt signal, the PU 20 interrupts the document reading process and stops the movement of the first traveling body 12. When the interrupt occurs, the CPU 20 detects the count value of the sub-scanning line counter and obtains the number of lines of the read image data from this count value.

In the fixed original reading mode, in order to detect the skew of the original, the prescan is performed before the image reading of the original, and the skew amount is detected in the same manner as described above.

Next, the processing operation when a skew occurs will be described with reference to the flowchart of FIG.

That is, the operator operates the operation / display unit 33.
Select the document skew amount detection mode with (S1 YE
S) and when setting the skew reference value (YES in S2), an arbitrary reference amount B can be set by the operation / display unit 33 (S3). If you do not set the skew reference value,
(S2 NO), default value B'will be set
(S4). When the document is conveyed (S5), the CPU 20 detects the document skew amount in the same manner as described above for each reading of the document (S6), and the skew amount A obtained by this detection and the skew amount A If it is compared with the value B or B ′, and A ≦ B, B ′ (NO in S7), it is judged that the skew is within the allowable range, the original is read, and the original read data is fetched (S8), A>
If it is B or B '(YES in S7), it is determined that the skew is too large, and the status information (the number of the document, the skew amount, etc.) is output to the operation / display unit 33, and the post-processing operation is performed. (Error processing) is performed (S9).

As the post-processing operation, it is conceivable to stop the reading and re-read by setting the original again, continue the reading as it is, or eject the paper without reading the original. Here, the reading is performed. After stopping the operation, the operator / display unit 33 is caused to display the error status based on the status information, so that the operator can reread the original by resetting the document, continue reading the original without reading the original, depending on the contents of the display. In addition, any one of paper discharge and the like is appropriately selected so that an instruction can be input from the operation / display unit 33 to the CPU 20.

By doing so, it is possible to perform reading without document skew and prevent damage due to document skew.

As the post-processing operation, status information (number of originals, skew amount, etc.) is output to the host computer 32 via the I / F controller 31.
It is also possible to perform a post-processing operation (error processing).
In this case, the operator appropriately selects, from the contents displayed on the host computer 32, one of re-reading by re-setting the original, continuing reading, and discharging the original without reading the original, and the CPU 20 from the host computer 32 is selected. Enter instructions for.

In the post-processing operation, the skew amount is A> B,
It is also conceivable to control to automatically start when it becomes B '.

By making it possible to arbitrarily set the reference amount by the operation / display unit 33 or the host computer 32, it becomes possible to perform reading in accordance with the specification required by the operator for reading. When the scanner device has a skew correction function, the skew-free reading can be performed by setting a reference value that matches the correction function. In addition, the host computer 32 may have a skew correction function as application software, and by using it, a reference value that matches performance can be set to enable skew-free reading. You can

[0044]

As described above, according to the image reading apparatus of the present invention, even if the document skew occurs, the post-processing is performed according to the degree of the skew. It will be possible.

According to the second aspect of the invention, it is possible to perform post-processing according to the degree of document skew via the host computer.

According to the third aspect of the present invention, the reference value, which is the reference for determining the degree of document skew, can be set arbitrarily, so that the document that matches the operator's intention or the capability of the skew correction function provided is provided. Read is possible.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a scanner device that is an embodiment of an image reading device of the present invention.

FIG. 2 is a block diagram showing a control circuit in an embodiment of the image reading apparatus of the present invention.

FIG. 3 is a block diagram showing a configuration of an image processing unit in an embodiment of the image reading apparatus of the present invention.

FIG. 4 is an explanatory diagram of a fixed original reading mode.

FIG. 5 is an explanatory diagram of an ADF type reading mode.

FIG. 6 is an explanatory diagram of a uniform density member in one embodiment of the image reading apparatus of the present invention.

FIG. 7 is an explanatory diagram of density level detection by a uniform density member in an embodiment of the image reading apparatus of the present invention.

FIG. 8 is an explanatory diagram of a uniform density member portion when a skew occurs in the embodiment of the image reading apparatus of the present invention.

FIG. 9 is an explanatory diagram of density level detection by a uniform density member when a skew occurs in an embodiment of the image reading apparatus of the present invention.

FIG. 10 is a flowchart of a processing operation when a skew occurs in the embodiment of the image reading apparatus of the present invention.

[Explanation of symbols]

1 ... ADF (Automatic Document Feeder), 6 ... Document Holding Plate,
7 ... White reference plate, 12 ... First running body, 15 ... Second running body, 16 ... Photoelectric conversion element (CCD), 20 ... CPU, 27
... image processing unit, 28 ... scan buffer, 30 ... line buffer, 32 ... host computer, 33 ... operation / display unit, 35 ... analog video processing unit, 36 ... shading correction processing unit, 37 ... image data processing unit, 38 ... Binarization processing unit, 39 ... Timing generating unit, 40 ... Uniform density member.

Claims (3)

[Claims] 1. A photoelectric conversion element which is arranged one-dimensionally with respect to a document reading position, and image data of a document can be read and a document skew state can be detected by read data from the photoelectric conversion element. An image reading apparatus comprising: means and means for issuing status information and performing a post-processing operation when a skew of a predetermined reference value or more occurs. 2. A photoelectric conversion element arranged in parallel one-dimensionally with respect to a document reading position, and image data of a document can be read by the read data from the photoelectric conversion element and the skewed state of the document can be detected. And a means for issuing status information to a connected host computer to perform a post-processing operation when a skew of a predetermined reference value or more occurs. apparatus. 3. The image reading apparatus according to claim 1, wherein the reference value can be arbitrarily set.