JP2002185705A - Device and method for reading image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable image reader by suppressing the disturbance of foreign matter images due to foreign matters such as dust/scratches even while securing a high original read speed by reading a moving image of the original with a fixed reader (reading a moving image of the original). SOLUTION: A position of reading moving images of the original in the case that a detected original size is a stipulated size or smaller is defined as a first read position and the through position of reading moving images of the original in the case that the detected original size is larger than the stipulated size is defined as a second read position. Control is performed by reading the moving images of the original at the other read position in the case that the foreign matters such as the dust/scratches are detected at one of the first and second read positions and to read by fixed read in the case that the foreign matters are detected at both of the first and second read positions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image reading apparatus and a method having an original reading function for reading image information while the original is being conveyed.

[0002]

2. Description of the Related Art Conventionally, in addition to a fixed original reading method in which an original image placed on a platen glass is read by moving a scanner, an automatic original feeder reads an original image while being conveyed on the platen glass. 2. Description of the Related Art An image reading apparatus having a system is known. In this reading method, reading can be performed at the same time as document replacement, and there is no scanner moving time between documents, so that the reading time of the entire document bundle can be reduced as compared with the fixed document reading method.

[0003] In this apparatus, stability during document conveyance is improved.
In consideration of the first copy time and the like, a configuration in which the reading position is divided into a plurality of positions depending on the size of the document can be considered. For example, if the document size is a small size such as A4 or B5, the position where the trailing edge of the A4 paper passes through the paper feeding unit is set to a large size such as A3 or B4.
For example, the position where the rear end of the sheet of A3 passes through the sheet feeding unit is set as the reading position.

[0004]

However, since the original image is read at a fixed position on the platen glass, the original image is correctly read by foreign matter such as dust or dirt attached between the platen glass and the original or on the lower portion of the platen glass. In some cases, it could not be read.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is possible to secure a high original reading speed by a flow-reading operation and also to prevent a foreign matter image from being disturbed due to foreign matter such as dust and scratches. It is an object of the present invention to provide a highly reliable image reading apparatus and method.

[0006]

According to the present invention, there is provided an image reading apparatus comprising: a document placing means on which a document is placed; an automatic document feeding means for feeding the document onto the document placing means; Document size detecting means for detecting the size of the document, fixed reading means for reading the image of the document when the document is stopped on the document placing means, and document reading means for reading the image of the document. Moving reading means for reading while moving on the means, foreign matter detecting means for judging from the image signal obtained by the moving reading means whether or not the read image contains a foreign matter image; and A first reading position when the document size detected by the means is equal to or smaller than a specified size; and a moving reading position when the document size detected by the document size detection means is larger than the specified size. As the second reading position, when the foreign matter is detected at one of the first and second reading positions by the foreign matter detecting means, the foreign matter is read at the other reading position by the flowing reading means, When the foreign matter is detected at both the first and second reading positions, the control means controls the reading by the fixed reading means.

An image reading apparatus according to the present invention comprises: a document placing means on which a document is placed; an automatic document feeding means for feeding the document onto the document placing means; and a document for detecting the size of the document. A size detection unit, a fixed reading unit that reads the image of the original when the original is stopped on the original placing unit, and a moving unit that moves the image of the original on the original placing unit. A reading means for reading when
A foreign object detection unit that determines whether or not a foreign image is included in the read image from an image signal obtained by the drift reading unit; and a case where the document size detected by the document size detection unit is equal to or smaller than a specified size. First reading position
And the foreign object detecting means detects the foreign matter at the first reading position, with the moving reading position when the document size detected by the document size detecting means is larger than a specified size as the second reading position. Control means for controlling the reading by the flow reading means at the second reading position, and controlling to read by the fixed reading means when the foreign matter is detected at the second reading position. And characterized in that:

An image reading apparatus according to the present invention is an image reading apparatus for reading a document image by irradiating light on a document surface, wherein when the document is placed and light is irradiated on the document surface, irradiation light is emitted. Control means for selectively setting a stop reading function for reading a document image in a state where the document is stopped and a flow reading function for reading a document image in a state where the document is moving with respect to the document placing surface serving as a passage portion Document size detecting means for detecting the size of the document, and foreign matter detecting means for detecting the presence or absence of foreign matter on the document placing surface, wherein the document size detected by the document size detecting means is equal to or smaller than a specified size. When the moving reading position at that time is a first reading position, and the moving reading position when the size is larger than the fixed size is a second reading position, the control means controls the first foreign object detecting means to detect the first reading position.
And / or performing control of reading a document image by a predetermined one of the functions in response to a case where the foreign matter is detected at the second reading position.

In one aspect of the image reading apparatus of the present invention, the control means is configured to control the first and second detecting means by the foreign matter detecting means.
When the foreign matter is detected at one of the reading positions, the reading is performed at the other reading position by the drift reading function, and when the foreign matter is detected at both the first and second reading positions. Is controlled to read by the stop reading function.

In one aspect of the image reading apparatus of the present invention, when the foreign matter is detected at the first reading position by the foreign matter detecting means, the control means sets the foreign matter at the second reading position. When the foreign matter is detected at the second reading position, the reading is controlled by the stop reading function.

The image reading method according to the present invention is a method for reading an original image by irradiating the original surface with light, wherein the original is placed on the original surface, and when the original surface is irradiated with light, a portion through which the irradiated light passes. It is possible to selectively set a stop reading function for reading a document image in a state where the document is stopped and a flow reading function for reading a document image in a state where the document is moving, with respect to the document placing surface to be set. The size of the document is detected, and the flow reading position when the detected document size is equal to or smaller than a predetermined size is set as a first reading position, and the flow reading position when the size is larger than the fixed size is set as a second reading position. When detecting the presence or absence of a foreign matter on the document placing surface, the image of the document is determined by a predetermined one of the functions corresponding to a case where the foreign matter is detected at the first and / or second reading position. Control read It is characterized in.

In one aspect of the image reading method of the present invention, when the foreign matter is detected at one of the first and second reading positions, the foreign material is read at the other reading position by the flow reading function. When the foreign matter is detected at both the first and second reading positions, control is performed so that the foreign matter is read by the stop reading function.

In one aspect of the image reading method of the present invention, when the foreign matter is detected at the first reading position, the foreign matter is read at the second reading position by the drift reading function.
Further, when the foreign matter is detected even at the second reading position, control is performed so that reading is performed by the stop reading function.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments to which the present invention is applied will be described below in detail with reference to the drawings.
In the present embodiment, a digital copying machine is exemplified as the image reading device.

FIG. 1 is a block diagram showing the configuration of a digital copying machine according to this embodiment. The reader unit 1 reads an image of a document, and outputs image data corresponding to the document image to the image memory unit 3. The printer unit 2 records an image corresponding to the image data from the image memory unit 3 on a recording sheet. The image memory unit 3 compresses the image data transferred from the reader unit 1, stores the compressed image data, expands the stored compressed image data, and stores the expanded image data. Transfer to the printer unit 2.

The stored image data is transferred to an external I / O
The image data transferred to the F processing unit 4 and stored from the external I / F processing unit 4 are stored. The external I / F processing unit 4 performs predetermined processing on the image data transferred from the image memory unit 3, outputs the processed data to an external device, performs predetermined processing on the image data sent from the external device, and performs image processing. The data is transferred to the memory unit 3.

The automatic document feeder 6 is connected to the reader unit 1 and feeds the placed document to a predetermined position.

FIG. 2 is a sectional view showing the configuration of the digital copying machine according to this embodiment. In the figure, reference numeral 200 denotes a main body of the digital copying machine 199, and reference numeral 6 denotes an automatic document feeder (DF).

Reference numeral 201 denotes a platen glass serving as a document placing table; and 202, a scanner. The scanner is reciprocally scanned in a predetermined direction by a motor (not shown) including a document illumination lamp 203, a scanning mirror 204, and the like, and reflected light of the document. Is transmitted through the lens 207 via the scanning mirrors 204 to 206 to form an image on the CCD sensor in the image sensor unit 208.

Reference numeral 209 denotes an exposure control unit composed of a laser, a polygon scanner, or the like. The exposure control unit 209 is converted into an electric signal by the image sensor unit 208, and is modulated based on an image signal subjected to predetermined image processing described later. Light 219 is applied to the photosensitive drum 211.

Around the photosensitive drum 211, a primary charger 212, a developing device 213, a transfer charger 216, a separation charger 217, a pre-exposure lamp 214, a cleaning device 21
5 is equipped. In the image forming unit 210, the photosensitive drum 211 is rotated by a motor (not shown) in a direction indicated by an arrow, and is charged to a desired potential by a primary charger 212. 2
Irradiation is performed to form an electrostatic latent image.

The electrostatic latent image formed on the photosensitive drum 211 is developed by a developing device 213 and visualized as a toner image. On the other hand, pickup rollers 225, 226, and 209 are provided from the right cassette deck 221, the left cassette deck 222, the upper cassette 223 or the lower cassette 224.
The transfer paper fed by 227, 228 is sent to the main body by paper feed rollers 229, 230, 231, 232,
The toner image fed to the transfer belt by the registration roller 233 and visualized is transferred to the transfer paper by the transfer charger 216.

After the transfer, the photosensitive drum is cleaned of residual toner by a cleaner device 215 and the pre-exposure lamp 21
4 erases the residual charge. The transfer paper after the transfer is separated from the photosensitive drum by the separation charger 217 and sent to the fixing device 235 by the transfer belt 234. In the fixing device, the toner is fixed by pressure and heat, and is discharged to the outside of the main body 200 by the discharge roller 236.

On the right side of the main body 200, for example, about 4000
A deck 250 capable of storing a sheet of transfer paper is provided. The lifter 251 of the deck 250 rises according to the amount of transfer paper so that the transfer paper always contacts the pickup roller 252, and the transfer paper is sent to the main body by the paper feed roller 253. Further, a multi-bypass tray 254 capable of storing 100 transfer sheets is provided.

Further, in FIG. 2, reference numeral 237 denotes a paper discharge flapper, which switches the path of the transport path 238 and the path of the discharge path 243. A lower transport path 240 guides the transfer sheet sent from the sheet discharge roller 236 to a re-feed path 241 by turning the transfer sheet upside down via a reversing path 239. The transfer paper fed from the left cassette deck 222 by the paper feed roller 230 is also guided to the refeed path 241. Reference numeral 242 denotes a re-feed roller for re-feeding the transfer sheet to the image forming unit 210. 244 is disposed near the discharge flapper 237,
A discharge roller that discharges the transfer paper switched to the discharge path 243 by the discharge flapper 237 to the outside of the apparatus.
At the time of double-sided recording (double-sided copying), the discharge flapper 237 is raised upward, and the copied transfer sheet is re-passed through the transport path 238, the reverse path 239, and the lower transport path 240.
Lead to 1.

At this time, the rear end of the transfer sheet is completely pulled out of the transport path 238 by the reversing roller 245, and the transfer sheet is pulled into the reversing path 239 to a position where the transfer sheet is bitten by the reversing roller 245, thereby reversing the reversing roller 245. Thus, the sheet is sent to the lower transfer path 240.

When the transfer paper is inverted and discharged from the main body, the discharge flapper 237 is raised upward, and
5, the rear end of the transfer paper is drawn into the reversing path 239 to a position where the rear end of the transfer paper remains in the conveying path 238,
By reversing 5, the transfer paper is turned over and sent out to the discharge rollers 244. The paper discharge processing device 290 stacks transfer paper discharged from the main body 200 of the digital copier one by one on the processing tray 294 and aligns them. When the discharge of one copy is completed, the transfer paper bundle is stapled and the discharge tray 29 is discharged.
2 or 293 to discharge in bundles.

The discharge tray 293 is controlled to move up and down by a motor (not shown), and moves to the position of the processing tray before the start of the image forming operation. Reference numeral 291 denotes a paper tray on which separator paper to be inserted between the discharged transfer papers is loaded.
Reference numeral 5 denotes a Z-folding machine that Z-folds the discharged transfer paper.
Reference numeral 296 denotes a bookbinding machine for executing bookbinding by folding the center of a part of the transferred transfer papers together and performing stapling. The bundle of bound papers is discharged to a discharge tray 297.

FIG. 3 is a control block diagram showing the inside of the digital copying machine 199. Reference numeral 171 denotes a CPU for performing basic control of the digital copying machine 199, a ROM 174 in which a control program is written, and a work RAM 1 for performing processing.
75, the input / output boat 173 is connected by an address bus and a data bus.

The input / output boat 173 is connected to various loads (not shown) such as motors and clutches for controlling the digital copying machine 199, and inputs (not shown) such as sensors for detecting the position of paper. .

The CPU 171 controls input and output sequentially through the input / output boat 173 in accordance with the contents of the ROM 174 to execute an image forming operation. An operation unit 172 is connected to the CPU 171 and controls a display unit and a key input unit of the operation unit 172.

The operator instructs the CPU 171 to switch the display between the image forming operation mode, the scanner reading mode, and the print output mode through the key input means.
Reference numeral 71 indicates the state of the digital copying machine 199 and the operation mode setting by key input.

The CPU 171 includes an image sensor 20
Image processing unit 1 that processes the signal converted into an electric signal in 8
70, an image memory unit 3 for storing processed images, and a dust determination unit 176 for detecting foreign matter such as dust and scratches on the platen glass 201 from a signal digitized by the image processing unit 170. I have.

Next, based on FIG.
Will be described. FIG. 4 is a block diagram illustrating the image processing unit. The original image formed on the CCD sensor via the lens 207 is input as black luminance data, and is converted into an analog electric signal by the CCD sensor. The converted image information is input to an analog signal processing unit (not shown), and after sample and hold, dark level correction, and the like are performed, the A / D conversion unit 501 performs analog-to-digital conversion (A / D conversion). Then, the digitized signal is subjected to shading correction (correction of variations in a sensor for reading a document and light distribution characteristics of a document illumination lamp).

After that, it is sent to the 1 log converter 502.
The 1 log converter 502 stores an LUT for converting the input luminance data into density data, and converts the luminance data into density data by outputting a table value corresponding to the input data.

Thereafter, the image is scaled to a desired magnification by the scaling unit 503 and input to the γ correction unit 504. γ
When outputting the density data, the correction unit 504 performs conversion using an LUT in consideration of the characteristics of the printer, and adjusts the output according to the density value set by the operation unit.

After that, it is sent to the binarizing section 505. The binarization unit 505 binarizes the multi-value density data, and the density value becomes “0” or “255”. The 8-bit image data is binarized and converted into 1-bit image data of “0” or “1”, and the amount of image data stored in the memory is reduced.

However, when the image is binarized, the gradation of the image is changed from 256 gradations to two gradations. Therefore, when binarizing image data such as a photographic image, image deterioration is generally remarkable. . Therefore, it is necessary to perform pseudo halftone expression using binary data.

Here, an error diffusion method is used as a technique for pseudo-halftone expression using binary data. This method uses “2” when the density of a certain image is larger than a certain threshold value.
55, and if it is less than a certain threshold value, it is binarized as being “0” density data,
In this method, the difference between the actual density data and the binarized data is distributed to surrounding pixels as an error signal.

The distribution of the error is performed by multiplying an error generated by the binarization by a weight coefficient on a matrix prepared in advance and adding the multiplied error to surrounding pixels. As a result, the density average value of the entire image is stored, and the halftone can be represented in a pseudo binary manner. 2
The digitized image data is sent to the image memory unit 3 and is stored in the image.

The image data input from the external I / F processing unit 4 from the computer is processed as binary image data by the external I / F processing unit, and is thus sent to the image memory unit 3 as it is. . The image memory unit 3 has a high-speed page memory and a large-capacity memory (hard disk) capable of storing a plurality of page image data. The plurality of image data stored in the hard disk are output in an order according to the editing mode specified by the operation unit of the digital copying machine 199. For example, in the case of sorting, the images of the document bundle read from the automatic document feeder 6 are sequentially output.

The image data of the document stored once is read from the hard disk, and this is repeated and output plural times. Thereby, it can play the same role as a sorter having a plurality of bins. The image data output from the image memory unit 3 is sent to a smoothing unit 506 in the printer unit 2. The smoothing unit 506 performs data interpolation so that the line ends of the binarized image are smoothed, and outputs image data to the exposure control unit 209. Exposure controller 20
In step 9, the image data is formed on the transfer paper by the above-described processing.

Also, at the time of dust determination to be described later, the lens 2
The read image formed on the CCD sensor via 07 is digitized in the same manner as in the case of a document image, and is sent to the dust determination unit 176 after shading correction. Dust determination unit 176
Then, the input signal is added in the document feed direction in pixel units, and if the addition result exceeds a certain level, it is determined that dust is attached to the pixel portion.

Next, details of the image memory unit 3 will be described with reference to FIG. In the image memory unit 3, an external I / F processing unit 4 and an image processing unit 1 are stored in a page memory unit 301 including a memory such as a DRAM via a memory controller unit 302.
70, writing of a binary image from the external I / F processing unit 4,
The image reading to the printer unit 2 and the input / output access of the image to the hard disk 304 which is a large-capacity storage device are performed. The memory controller unit 302 generates a DRAM refresh signal for the page memory 301,
It arbitrates access to the page memory 301 from the image I / F processing unit 4, the image processing unit 170, and the hard disk 304.

Further, in accordance with an instruction from the CPU 171, the write address to the page memory unit 301, the read address from the page memory unit 301, and the read direction are controlled. As a result, the CPU 171 arranges a plurality of document images in the page memory unit 301 and performs layout.
It controls the function to output to the printer unit, the function to cut out and output only part of the image, and the image rotation function.

Next, according to FIG. 6, the external I / F processing unit 4
Is described. As described above, the external I / F processing unit 4
Via the image memory unit 3, the binary image data of the reader unit is taken into the external I / F processing unit, and the binary image data from the external I / F is passed through the image memory unit 3 to the printer unit 2.
To form an image.

The external I / F processing unit 4 includes a core unit 406, a facsimile unit 401, a hard disk 402 for storing communication image data of the facsimile unit, and an external computer 1
1 and a computer interface unit 403 connected to
And a formatter unit 404 and an image memory unit 405. Facsimile unit 401 is a modem (not shown)
, And receives facsimile communication data from the public line and transmits facsimile communication data to the public line.

The facsimile unit 401 stores a facsimile image on the hard disk 402, such as performing facsimile transmission at a designated time or transmitting image data from a partner during a designated password. Perform processing. Thereby, once the reader unit 1
From the facsimile unit 401 via the image memory unit 3
After the image is transferred to the facsimile hard disk 402, fax transmission can be performed without using the reader unit 1 and the image memory unit 3 for the facsimile function.

Computer interface unit 403
Is an interface for data communication with an external computer, and is a local area network
LAN), a serial I / F, a SCSI I / F, a centro I / F for printer data input, and the like. Via this I / F, the statuses of the printer unit and the reader unit are notified to an external computer, and the image read by the reader unit 1 is transferred to the external computer according to instructions from the computer.

Further, it receives print image data from an external computer. Since the print data notified from the external computer via the computer interface unit 403 is described in a dedicated printer code, the formatter unit 404 forms the image in the printer unit 2 via the image memory unit 3. Convert to raster image data.

The formatter unit 404 develops raster image data in the image memory unit 405. The image memory unit is used as a memory in which the formatter unit 404 expands raster image data, or when the image of the reader unit is sent to an external computer via the computer interface unit 403 (image scanner function). It is also used when the image data sent from the image memory unit 3 is once expanded in the image memory unit, converted into a data format to be sent to an external computer, and then sent out from the computer interface unit 403.

The core unit 406 includes a facsimile unit 401,
Computer interface unit 403, formatter unit 404, image memory unit 405, image memory unit 3
Control and manage each data transfer during This allows
Even if the external I / F processing unit 4 has a plurality of image output units or the image memory unit 3 has a single image transfer path, the core unit 4
Under the management of 06, exclusive control and priority control are performed, and image output is performed.

Next, the operation of the automatic document feeder (DF) 6 in the present embodiment will be described with reference to FIGS. 7A to 10M which are schematic sectional views of the automatic document feeder 6.
First, each part of the automatic document feeder 6 will be described with reference to FIG. The paper feed roller 601 falls on the original surface of the original bundle 621 placed on the original tray 620 on which the original bundle 621 composed of at least one or more sheets is placed, and rotates, thereby causing the uppermost surface of the original bundle. Original D is fed.

The stopper 611 protrudes as shown in FIG. 7A before the start of document feeding, and the document bundle 621 is restricted by the stopper 611 so that it cannot advance downstream. The document fed by the paper feed roller 601 is separated into one sheet by the operation of the separation roller 602 and the separation belt 603. Separation is realized by a well-known liquid separation technique.

The conveyance roller 604 conveys the document separated by the separation roller 602 and the separation belt 603 to the registration roller 605, hits the document against the registration roller 605, and forms a loop, thereby forming a skew in the conveyance of the document. To eliminate.

Below the registration roller 605, a document path passing through the registration roller 605 and a paper feed path 652, which is a conveyance path in the direction of the platen 201, or a reversing LOHAS 6
A reversing paper feed flapper 613 for guiding to 53 is provided.

First reversing roller 614 and second reversing roller 6
Reference numeral 15 rotates when the document is reversed. The reversing flapper 612 guides a document arriving from the direction of the second reversing roller 615 to the reversing path 650 or the re-feeding path 651.

A belt driving roller 606 drives a feeding belt 607 for arranging a document on a platen. The feeding belt 607 is in contact with the platen 201. The paper feed / discharge roller 617 feeds / discharges the document supplied from the manual paper feed port 622 and discharges the document D fed by the feed belt 607 to the document discharge port 623. Paper ejection flapper 6
16 is a manual feed / discharge path 654 or a document discharge path 6;
The document is guided to 55. The paper discharge flapper 616 acts to prevent the document from being discharged toward the manual paper discharge port 622 when the document is discharged. The manual feed / discharge roller 619 feeds / discharges a manual document. The discharge roller 618 discharges the document.

Further, three sensors 608, 609 and 610 are arranged below the document tray 620. The document set detection sensor 610 is a transmissive optical sensor that detects that the document bundle 621 has been set. The document trailing edge detection sensor 608 is a reflection type optical sensor for determining whether the document is a half size document. A final document detection sensor 609 between the document set detection sensor 610 and the document trailing edge detection sensor 608 is a reflection type optical sensor for determining whether the document being transported is the final document.

Document size detection sensors 624 and 62
Reference numerals 5 and 626 denote sensors for detecting the size of the original being conveyed. Three sensors are arranged in the width direction of the original.
The document width is detected in three stages based on the sensor values of
The system, or the document width of A4 and A5 can be determined. Also, the length of the original can be detected based on the passage time of the original. This makes it possible to detect individual document sizes even in a document bundle in which documents of different sizes are mixed. However, at this time, the bundle of originals is placed with the back side in the width direction of the originals aligned.

Next, the operation of the automatic document feeder 6 when reading both sides of a document printed on both sides (double-sided document) will be described. When the automatic document feeder 6 is instructed to start feeding double-sided documents, the stopper 611 is lowered, and the paper feed roller 601 is further dropped on the upper surface of the document (FIG. 7).
(B)). By the operation of the paper feed roller 601, the separation roller 602, the separation belt 603, and the transport roller 604, only one document is separated from the uppermost surface of the document bundle 621 and fed to the registration roller 605 (FIG. 7C). . At this time, the reversing paper feed flapper 613 is set in the direction of transporting the original to the reversing path 650.

When the registration roller 605 rotates, the original is conveyed to the position shown in FIG. 8E via the path shown in FIG. 7D. From here, the driving directions of the first reversing roller 614 and the second reversing roller 615 are reversed, the document is fed onto the platen 201, and stops at the position shown in FIG.

When the reading of the original is completed, FIG.
As shown in FIG. 8, the original is reversed via the re-feed path 651, and is again fed onto the platen 201 as shown in FIG.

When the reading of the original document is completed, the original document D is fed rightward and is discharged from the automatic document feeder 6 through the document discharge port 623. By repeating the above operation, the automatic document feeder 6 can separate the double-sided document from the uppermost surface at a time, scan both sides, and discharge the document with the upper surface facing down (face down).

Next, the scanner 202 is fixed at a predetermined position, and the operation of the original reading method (flow reading) for reading the image by moving the original is described in the case where the original is only the small size and the case where the large size is included. I will explain separately.

In the present embodiment, the small size is a size at which the document trailing edge detection sensor 608 does not detect a document when the document bundle 621 is placed on the document tray 620, and is an A4 size, an LTR size, or the like. The large size is a size at which the document trailing edge detection sensor 608 detects a document when the document bundle 621 is placed on the document tray 620, and is an A3 size, an 11 × 17 size, or the like.

First, the flow-reading of a small-size original will be described. The operation until the document reaches the registration rollers 605 is as described with reference to FIGS. 7A to 7C. In the case of the flow reading, as shown in FIG. 9I, the reversing sheet feeding flapper 613 guides the document onto the platen 201.

The original is conveyed at a predetermined speed above point A in the figure, and the image of the original is
02 (FIG. 9 (j)). At this time, a signal to start reading is notified to the reader unit 1 at the timing when the leading edge of the document passes the point A. The read document D is conveyed to the right in the figure as it is, and is discharged out of the automatic document feeder 6 from the document discharge port 623 (FIG. 9 (k)).

Point A is A0, A1, A2, A3, A4, A
The position where the rear end of the LTR size document has passed through the registration roller 605 is defined as A0, and A1, A2,. The readable position determined by the dust determination described later is stored, and at the time of reading, an instruction is issued to the scanner 202 and the automatic document feeder 6 to perform reading at the stored position.

Next, the flow reading of a document including a large size will be described. The operation until the document reaches the registration rollers 605 is as described with reference to FIGS. 7A to 7C.

In the case of the flow-reading of the original including the large size, as shown in FIG. 10A, the reverse feed flapper 613 guides the original onto the platen 201. The document is conveyed at a predetermined speed above point B in the figure, and the image of the document is read by the scanner 202 waiting below point B. At this time, a reading start signal is notified to the reader unit 1 at the timing when the leading edge of the document passes the point B. The read document D is conveyed to the right in the figure as it is, and is discharged out of the automatic document feeder 6 through the document discharge port 623 (FIG. 10 (m)).

Point B is B0, B1, B2, B3, B4, B
The position where the rear end of the 11 × 17 size document has passed through the registration roller 605 is defined as B0, and B1, B2,. The readable position determined by the dust determination described later is stored, and at the time of reading, an instruction is issued to the scanner 202 and the automatic document feeder 6 to perform reading at the stored position.

Finally, in the case of fixed original reading in which the scanner 202 is moved to read an image, the original is placed at a position where the rear end of the original matches the end of the platen 201 (the position shown in FIG. 8H).

Next, the direction of the document bundle 621 set on the document tray 620 of the automatic document feeder 6 (see FIG. 7) and the document bundle 6 conveyed and discharged to the document discharge port 622
FIG. 11 shows how the directions of 21 correspond. The document shown on the left side of FIG. 11 is a document bundle 621 set on the document tray 620. Since the document is conveyed in order from the number 1 document on the top surface of the document and is output with its front and back reversed, as shown on the right side of FIG. 11, the top document is reversed and its top surface is changed to the bottom surface. Is discharged.

A control example in the case where an automatic scaling function for calculating an optimum scaling ratio based on the original size and the output paper size is set in the image reading apparatus having the above configuration will be described. When the automatic scaling function is set, if the document bundle placed on the automatic document feeder is composed of documents of the same size, the first sheet of the document bundle is fed onto the platen,
The original size is detected during the feeding, and the original image is read by the fixed original reading.
Control is performed such that an original image is read by original scanning while the original is being conveyed by the automatic original feeder.

However, if the variable magnification is a magnification that cannot be read continuously, control is performed so that the original image is read by the fixed original reading. Even if the bundle of originals placed on the automatic document feeder is composed of documents of different sizes (document mixed mode), it is necessary to calculate the scaling ratio for each document. Control is performed so as to read the original image.

FIG. 12 is an explanation of a basic flow relating to the dust detection operation. When performing a drift reading operation in which an image is read by using the document conveyance by the document conveyance unit 280, the time during which the image reading operation is not performed is used (S
101, S102)), the feed belt 207 is idly rotated in the state where there is no original, and the image is read with the current moving reading position. Normally, the original conveying means 28
The image of the surface of the feeding belt 607 which is included in 0 is input.

However, when dust adheres to the platen glass 201, a continuous image in the sub-scanning direction is detected in the read image signal. After driving the feed belt 607 for a certain period of time and reading the image, if such an image that is considered to be due to dust is detected, the flow reading operation cannot be continuously performed at the position where the previous reading was performed. Judge. If no abnormal image as described above is detected, the flow reading at that position is performed continuously.

When the stain on the platen glass at the moving reading position is detected, the scanner 202 is moved leftward to the position A0 to detect a position where the moving reading operation is possible (S104). A1 and A2, and a process of sequentially searching for the position at which the document can be read continuously are performed.

First, it is moved to a predetermined position, and is set as a next candidate position at which streaming reading is possible. In order to detect whether or not it is possible to scan the document at that position (whether there is no dust), the above-described image reading operation for dust detection (feed belt idle rotation, image reading, image judgment) is performed. (S106).

When it is determined that there is no dust, it is determined that the position can be read, and after the next flow reading operation, the flow reading operation at that position is performed. If dust is also detected in the re-detection operation, the process is repeated until a position where it can be determined that moving is possible by a fixed amount in the right direction and dust detection is determined to be readable is determined.

As a result of dust detection at a predetermined number of reading positions, dust is detected at all positions, and it is determined that image reading cannot be performed by flowing reading, and the state of the copying machine is set to a garbage state (S109). . Until a predetermined process determines that the flow reading is possible, the reading operation by the flow reading is not performed.

The image forming apparatus having the above configuration has small size, large size, and a flow reading prohibition flag at each position, and performs flow reading based on the result of the dust detection operation at each position. An example of control for determining whether or not this is the case will be described.

FIG. 13 is a flowchart showing a control method at this time. The control is started when a document is set and a mode of reading by flowing reading is set. First, in step S201, it is determined whether the bundle of originals placed on the automatic document feeder 6 is a small-size bundle of originals. If it is a small-size document bundle, step S202
Then, it is determined whether or not the drift reading prohibition flag at the point A stored as the small size reading position is set. If the flow-reading prohibition flag is not set, the flow-reading can be performed, so that the process proceeds to step S203, and the point A (A0 to A5) stored as the reading position is read.
Move the scanner to one of

Subsequently, the flow advances to step S204 to feed the first original document from the upper surface of the bundle of original documents and perform a reading process.

Next, the flow advances to step S205 to determine whether or not the fed original is the final original and the reading process has been completed. If not completed, return to step S204,
The reading process is continued. If the reading process has been completed in step S205, the process proceeds to step S206 to perform a dust detection operation at the small-sized reading position.

Subsequently, the process proceeds to step S207, where S20
As a result of the dust detection of No. 6, it is determined whether or not there is dust at all points A. If there is no dust at all points A, step S
Proceeding to step 208, the points where there is no dust of A0 to A5 are stored as subsequent small-size drift reading positions.

Next, the flow advances to step S218, where the scanner is moved to the home position at the time of standby, and the processing is terminated. In step S207, if there is dust at all points A, the process proceeds to step S209, and a flow reading prohibition flag at point A, which is a small-sized reading position, is set.

On the other hand, if the original bundle placed on the automatic document feeder 6 is not a small-size original bundle in step S201, and if the small-size reading position stored in step S202 is stored as the small-size reading position.
If the point-by-point reading prohibition flag has been set, the process proceeds to step S210, and it is determined whether or not the point B-point reading prohibition flag stored as the large-sized reading position has been set.

If the flow-reading prohibition flag is not set, the flow-reading can be performed, so that the process proceeds to step S211 and point B (B0 to B5) stored as the reading position is read.
Move the scanner to one of

Thereafter, after performing the operations from step S212 to step S213 as in the case of the small size,
Proceeding to step S214, a dust detection operation is performed at the large-size reading position.

Subsequently, the flow advances to step S215, and to S21.
As a result of the dust detection of No. 4, it is determined whether or not there is dust at all B points. If there is no dust at all points B, step S
Proceeding to 216, the points where there is no dust of B0 to B5 are stored as the subsequent large-sized drift reading positions.

Next, the flow advances to step S218, where the scanner is moved to the home position at the time of standby, and the processing is terminated. In step S215, if there is dust at all points B, the process advances to step S217 to set the drift reading prohibition flag at point B, which is a large-sized reading position.

If the flow-reading prohibition flag at the point B stored as the large-size reading position is set in step S210, the reading operation cannot be normally performed in the large-size flow reading. Therefore, the reading method is switched to the fixed reading operation in which the reading operation can be performed normally without being affected by dust.

Then, the flow advances to step S219 to perform reading processing by fixed reading. Next, the process proceeds to step S220, and it is determined whether the fed document is the last document and the reading process is completed. If not completed, step S2
Returning to step 19, the reading process is continued. If the reading process has been completed in step S220, the process ends.

The above is the small size, large size,
This is a control example in the case of having a flow-reading operation prohibition flag at each position and determining whether or not to perform flow-reading based on the result of the dust detection operation at each position.

By performing the control as described above, even if the drift reading prohibition flag at the point A stored as the small-size reading position is set, the point B stored as the large-size reading position is set. To perform a reading operation. Furthermore, when the drift reading prohibition flag at the point B stored as the large size reading position is set, the reading method can be changed to perform the fixed reading.

Therefore, it is possible to always read the original image normally without being affected by dust, and to shorten the time required for the reading process as much as possible.

Here, in order to realize each function of the image reading apparatus of the above-described embodiment, various devices are operated so that a device connected to the various devices or a computer in the system is operated. Supply software program code to realize the function,
The present invention also includes those implemented by operating the various devices in accordance with a program stored in a computer (CPU or MPU) of the system or apparatus.

In this case, the program code of the software implements the functions of the above-described embodiment, and the program code itself and means for supplying the program code to a computer are provided.
For example, a storage medium storing such a program code constitutes the present invention. As a storage medium for storing such a program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, C
D-ROM, magnetic tape, nonvolatile memory card, R
OM or the like can be used.

When the computer executes the supplied program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) or other operating system running on the computer. Needless to say, even when the functions of the above-described embodiments are realized in cooperation with application software or the like, such program codes are included in the embodiments of the present invention.

Further, after the supplied program code is stored in the memory provided in the function expansion board of the computer or the function expansion unit connected to the computer, the program code is stored in the function expansion board or the function expansion unit based on the instruction of the program. The present invention also includes a case where a provided CPU or the like performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0103]

According to the present invention, it is possible to improve the productivity of the reading operation by suppressing the disturbance of the foreign matter image caused by foreign matter such as dust and scratches while securing a high original reading speed by the flow reading operation. As a result, a highly reliable image reading apparatus can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a digital copying machine according to an embodiment.

FIG. 2 is a cross-sectional configuration diagram illustrating a digital copying machine according to the present embodiment.

FIG. 3 is a block diagram showing a control state in the digital copying machine.

FIG. 4 is a block diagram illustrating an image processing unit.

FIG. 5 is a configuration diagram showing an image memory unit in detail.

FIG. 6 is a configuration diagram illustrating an external I / F processing unit.

FIG. 7 is a sectional view showing an automatic document feeder.

FIG. 8 is an explanatory diagram illustrating a document feeding operation in the automatic document feeder.

FIG. 9 is an explanatory diagram showing a document feeding operation in the automatic document feeder.

FIG. 10 is an explanatory diagram showing a document feeding operation in the automatic document feeder.

FIG. 11 is an explanatory diagram illustrating a direction of a document bundle discharged from a document discharge port.

FIG. 12 is a flowchart illustrating an outline of a dust detection operation.

FIG. 13 is a flowchart illustrating a moving reading position switching process.

[Explanation of symbols]

 200: Image reading apparatus main body 201: Platen glass 202: Scanner 203: Document illumination lamp 204 to 206: Scanning mirror 207: Lens 208: Image sensor unit 209: Exposure control unit 210: Image forming unit 211: Photoconductor drum 212: 1 Next charger 213: Developing device 214: Pre-exposure lamp 215: Cleaning device 216: Transfer charger 217: Separation charger 219: Laser light 221: Right cassette deck 222: Left cassette deck 223: Upper cassette 224: Lower cassette 225, 226, 227, 228: Pickup rollers 229, 230, 231, 232: Paper feed roller 233: Registration roller 234: Transfer belt 235: Fixing device 236: Discharge roller 237: Discharge flapper 238: Convey path 239: Reverse path 240: under Feeding path 241: Refeeding path 242: Refeeding roller 243: Ejection path 244: Ejection roller 245: Reversing roller 250: Deck 251: Lifter 252: Pickup roller 253: Feeding roller 254: Multi manual feed 280: Automatic document feed Apparatus (DF) 290: paper discharge processing device 291: paper tray 292, 293: paper discharge tray 294: processing tray 295: Z folding machine 296: bookbinding machine 297: discharge tray 601: paper feed roller 602: separation roller 603: separation Belt 604: Conveying roller 605: Registration roller 606: Belt driving roller 607: Feeding belt 608: Document trailing edge detection sensor 609: Final document detection sensor 610: Document set detection sensor 611: Stopper 612: Reverse flapper 613: Reverse paper feed Flapper 614: 1st inversion b Roller 615: second reversing roller 616: paper discharge flapper 617: paper supply / discharge roller 618: paper discharge roller 619: manual paper supply / discharge roller 620: document tray 621: original bundle 622: manual paper discharge port 623: document discharge Ports 624 to 626: Document size detection sensor 1 650: Reverse path 651: Refeed path 652: Feed path 653: Reverse entrance path

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/00 108 H04N 1/12 Z 1/10 1/10 1/107 (72) Inventor Yuichiro Maeda Tokyo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Rieko Akiba 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2H012 CA08 2H076 BA20 BA59 BA62 BB04 EA21 5B047 AA01 BA01 BA02 BB02 BC15 CA14 CB09 CB12 CB22 5C062 AA05 AB02 AB32 AB46 AC07 AC67 AE15 5C072 AA01 BA05 EA05 LA18 NA04 RA01 RA06 WA03 XA01

Claims (8)

[Claims] A document placement unit on which a document is placed; an automatic document feeder configured to feed the document onto the document placement unit; a document size detection unit configured to detect a size of the document; Fixed reading means for reading an image of a document when the document is stopped on the document placing means; and flow reading for reading the image of the document when the document is moving on the document placing means. Means, a foreign matter detecting means for determining whether or not a foreign image is included in the read image from an image signal obtained by the flow reading means, and a document size detected by the document size detecting means being smaller than a specified size. A first reading position when the document size is detected by the document size detection unit; and a second reading position when the document size detected by the document size detection unit is larger than a specified size. When the foreign matter is detected at one of the first and second reading positions by the means, the foreign document is read at the other reading position by the flowing reading means, and both of the first and second reading positions are read. And a control means for controlling the reading by the fixed reading means when the foreign matter is detected. 2. An original placing unit on which an original is placed, an automatic original feeding unit for feeding the original onto the original placing unit, an original size detecting unit for detecting the size of the original, Fixed reading means for reading an image of a document when the document is stopped on the document placing means; and flow reading for reading the image of the document when the document is moving on the document placing means. Means, a foreign matter detecting means for determining whether or not a foreign image is included in the read image from an image signal obtained by the flow reading means, and a document size detected by the document size detecting means being smaller than a specified size. A first reading position when the document size is detected by the document size detection unit; and a second reading position when the document size detected by the document size detection unit is larger than a specified size. Means for reading the foreign matter at the first reading position, reading by the flow reading means at the second reading position, and further reading the foreign matter at the second reading position. And a control means for controlling reading by the fixed reading means. 3. An image reading apparatus for irradiating a document surface with light to read a document image, wherein the document is placed on the document surface and serves as a passage portion of the irradiation light when the document surface is irradiated with light. Control means for selectively setting a stop reading function for reading a document image in a state where the document is stopped, and a flow reading function for reading a document image in a state where the document is moving; Document size detecting means for detecting the size of the document, and foreign matter detecting means for detecting the presence or absence of a foreign matter on the document placing surface, the flow reading position when the document size detected by the document size detecting means is less than a specified size The first reading position is the second reading position when the reading position is larger than the predetermined size.
In response to a case where the foreign matter is detected at the first and / or second reading position by the foreign matter detecting means, the control unit controls the document by a predetermined one of the functions. An image reading apparatus for performing control for reading an image. 4. When the foreign matter is detected in one of the first and second reading positions by the foreign matter detecting means, the control means executes the flow reading function at the other reading position. 4. The image reading apparatus according to claim 3, wherein when the foreign matter is detected at both the reading position and the first and second reading positions, control is performed such that the reading is performed by the stop reading function. 5. 5. The control means, when the foreign matter is detected at the first reading position by the foreign matter detecting means, reads the foreign matter at the second reading position by the flow reading function, and further comprises: The image reading apparatus according to claim 3, wherein when the foreign matter is detected even at the second reading position, control is performed such that reading is performed by the stop reading function. 6. An image reading method for irradiating an original surface with light to read an original image, wherein the original is placed on the original surface and becomes a passage portion of irradiation light when the original surface is irradiated with light. A stop reading function for reading a document image when the document is stopped, and a flow reading function for reading a document image while the document is moving can be selectively set with respect to the placing surface, The size is detected, and the flow reading position when the detected document size is equal to or smaller than the specified size is set as a first reading position,
When the presence or absence of a foreign substance on the original placing surface is detected, the foreign substance is detected at the first and / or second reading position when the moving reading position when the size is larger than the fixed size is set as a second reading position. An image reading method for controlling the reading of a document image by a predetermined one of the functions corresponding to the case. 7. When the foreign object is detected at one of the first and second reading positions, the foreign object is read at the other reading position by the flow reading function, and the first and second reading operations are performed. The image reading method according to claim 6, wherein when the foreign matter is detected at both positions, control is performed such that the foreign matter is read by the stop reading function. 8. When the foreign matter is detected at the first reading position, reading is performed at the second reading position by the flowing reading function, and the foreign matter is also detected at the second reading position. 7. The image reading method according to claim 6, wherein in the case, control is performed so as to read by the stop reading function.