JP2011024098A - Document reading apparatus, control method thereof and automatic document feeder - Google Patents

Abstract

A document reading apparatus that improves the reading productivity in a mixed document loading mode and is user-friendly.
A document reading apparatus determines a document width from detection information of a document width detecting sensor and a conveyance guide regulating plate (S10). From this width information and the document length based on the detection information of the tray size detection first sensor 10 and the tray size detection second sensor 11, the maximum standard size is determined as the temporary document size (S11). The document reading apparatus 500 measures the actual document length by measuring the period from the ON to the OFF timing of the post-separation sensor 12, and determines the actual document size (S14). If the provisional document size is equal to the actual document size, the document reading device continues reading the image. If the document size is different, the document reading device returns the document via the reverse path, and performs image reading again (S20). .
[Selection] Figure 1

Description

  The present invention relates to a document reading apparatus that reads an image of a conveyed document, a control method thereof, and an automatic document feeder.

  Image processing apparatuses such as copying machines and facsimile machines are provided with an image reading apparatus. Some of various image reading apparatuses include an automatic document feeder (ADF).

  Many image processing apparatuses have a function that requires the document size to be detected before document image reading is started. Functions that require document size detection before image reading include an automatic paper selection function and an automatic magnification selection function.

  The automatic paper selection function is a function that automatically selects a paper of an appropriate size according to the document size, specified magnification, and presence / absence of image rotation processing. The automatic magnification selection function is a function that calculates and automatically sets the magnification of an image for enlarging or reducing the read document image in accordance with a specified paper size. Functions such as an automatic paper selection function and an automatic magnification selection function are executed by a controller in the image processing apparatus.

  Further, as a document image reading mode using the ADF, recently, a uniform width mixed document reading mode and a different width document mixed reading mode in which a document bundle made up of documents of different sizes has been becoming important. Even in the case of document image reading set in the same width / different width document mixed reading mode, high productivity has become a user's need.

  Here, when none of the mixed document reading modes of the same width / different width are set, all the documents are regarded as having the same size. For this reason, the standard document size is specified by the document width information when the document is set on the document tray of the ADF and the document length information in the feeding direction when the first document is transported.

  As a type of ADF, there is a type that has a large overall apparatus configuration and can lengthen a conveyance path length. With such an ADF, document width information and document length information can be determined before the leading edge of the document reaches the document reading position. On the other hand, in many of such ADFs, the overall configuration of the apparatus is large, which is heavy and expensive.

  On the other hand, depending on the type of ADF, there is an ADF having a relatively short document transport path. For example, the conveyance path length from the paper feed position to the document reading position of the document loaded on the document tray is shorter than an A4 size document (document width 297 mm × document length 210 mm) generally used by users. There is ADF.

  In such an ADF, the greatest merit is that a compact configuration can be taken. In the case of reading a bundle of documents with the same document size or normal reading, a sensor is provided on the document tray, and the document length information and document length are determined by determining the document length when the document is set on the document tray. The document size can be specified from the information.

  However, such an ADF with a relatively short document transport path has the following problems. If you want to scan a batch of documents with different document sizes one by one in the mixed width scanning mode, which automatically scans one document at a time while specifying the document size, and implement the automatic paper selection function and automatic magnification selection function, Requires different control. That is, there is a problem in that the document size cannot be specified before reading the document because the document width and document length for each sheet cannot be known simply by setting the document on the document tray.

  In order to specify the document size, such an ADF transports the document so that it circulates using a reversal transport path used for reversal when reading images on both sides of the document. The document size is specified by detecting the length in the document transport direction.

  Further, even in the same width original mixed reading mode, there is a similar problem because the length in the original conveying direction is not known for each sheet simply by setting the original on the original tray.

  Therefore, when reading in either the same width / different width original mixed reading mode, the ADF performs an empty reversal process by simply transporting the original in a circulating manner in order to specify the original size for each page. It was. Therefore, in the same width / different width original mixed reading mode, there is a problem that the reading productivity is inevitably lowered as compared with the normal standard size reading mode which is not the same width / different width original mixed reading mode.

  In addition, some ADFs consider such a problem, and perform document size prediction, so that no empty inversion processing is performed by this prediction.

  In the ADF described in Patent Document 1, when the document size is unknown in the same width / different width document mixed reading mode or the like, a document size candidate is extracted by detecting the width size. Is determined as the temporary document size.

JP 2006-074124 A

  However, the conventional document reading apparatus has the following problems. In other words, in the example described in Patent Document 1, when the document size is not predicted, the document is re-read by performing the idle rotation process. However, a device for reducing the time required for the idle rotation process has been devised. Absent. For example, if the actual document size is A3 size and the predicted document size is A4 size, an A3 size document whose length in the transport direction is twice the A4 size is idling. Compared with the A4 size, the time required for the idling process becomes very long. That is, Patent Document 1 does not mention anything about the document size prediction in consideration of efficiently performing the idling process.

  As described above, the conventional document reading apparatus cannot improve the reading productivity in the document mixed reading mode, and is not easy to use.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a document reading apparatus, a control method thereof, and an automatic document feeder that are easy to use for the user by improving the reading productivity in the mixed document loading mode.

  In order to achieve the above object, a document reading apparatus according to the present invention includes a stacking unit for stacking documents, a transport unit for transporting documents stacked on the stacking unit one by one so as to pass through a reading position, and A reading unit that reads an image of a document conveyed by the conveying unit at the reading position; and a return conveyance path for returning the document conveyed by the conveying unit after passing the reading position to a position upstream of the reading position; In a document reading apparatus in which the length of a document in the transport direction by the transport unit is not determined before the document reaches the reading position, the transport direction of the document placed on the stacking unit and stacked on the stacking unit A first document length detection unit that detects a document length that is a length of the document; a width detection unit that detects a document width that is a length in a width direction orthogonal to the transport direction of the document; When a stack of originals in which a plurality of originals of different sizes are mixed is stacked on the loading unit, a prediction is made based on the original width detected by the width detection unit and the original length detected by the first original length detection unit. A temporary size determining unit that determines a maximum standard size among a plurality of standard sizes as a temporary document size, and measuring a length of the document being conveyed by the conveying unit in a conveying direction. An actual document size is determined based on the second document length detection unit to be detected, the document width detected by the width detection unit, and the document length detected by the second document length detection unit; If the temporary document size determined by the size determination unit and the temporary size determination unit is equal to the actual document size determined by the actual size determination unit, the temporary document The reading of the image by the reading unit performed according to the size of the document is continued. On the other hand, if the temporary document size is different from the actual document size, the document is transferred by the transport unit via the return transport path. And a control unit that returns the image to an upstream position and causes the reading unit to read the original image again in accordance with the actual document size.

  According to a first aspect of the present invention, there is provided a document reading device having a plurality of standard sizes predicted based on a document width detected by a width detection unit and a document length detected by the first document length detection unit. The largest standard size is determined as the temporary document size. Further, the document reading apparatus determines the actual document size based on the length in the conveyance direction detected by the second document length detection unit. When the provisional document size is equal to the actual document size, the document reading apparatus continues reading the image performed according to the provisional document size. On the other hand, if the temporary document size and the actual document size are different, the document reading device returns the document to the upstream position via the return conveyance path, and reads the document image again according to the actual document size. Let it be done.

  As a result, when the provisional document size and the actual document size are equally predicted, it is possible to continue reading the document image without re-reading. On the other hand, even if the prediction is deviated, since the document size is shorter in the transport direction than the maximum document size, the time for returning the document to the position upstream from the reading position can be shortened. Accordingly, it is possible to improve the reading productivity in the document mixed loading mode and provide an automatic document feeder that is easy for the user to use.

  According to the document reading apparatus of the third aspect, when rereading occurs in preparation processing for the next document, there is a high possibility that extra repair processing such as canceling these processing will occur. Can be avoided. Therefore, no extra time is required for the re-reading operation.

1 is a cross-sectional view illustrating a configuration of a document reading device according to an embodiment. FIG. 6 is a diagram illustrating a document reading operation. FIG. 6 is a diagram illustrating a document reading operation. FIG. 6 is a diagram illustrating a document reading operation. 4 is a diagram showing various sensors arranged on a document tray 30. FIG. 2 is a block diagram illustrating configurations of an ADF 100, an image reading device 200, and a controller unit 400. FIG. 4 is a table showing the relationship between the document size and ON / OFF of the tray size detection first sensor 10 and the tray size detection second sensor 11 corresponding to the document size. 3 is a diagram showing a state in which a document bundle S made up of documents of different document sizes is set on the ADF 100. FIG. 5 is a flowchart showing a document reading operation procedure. 8 is a flowchart showing a document reading operation procedure continued from FIG. 7. 9 is a flowchart showing a document reading operation procedure following FIG. 7 and FIG. 8. FIG. 4 is a diagram showing a state where the leading edge of the first document is abutted against a registration roller 3. 6 is a table showing a document size assumed from the width of the conveyance guide regulating plate 18 and the number of detections of the document width detection sensor 17. It is a flowchart which shows the document re-reading sequence in step S20.

  Embodiments of a document reading apparatus, a control method thereof, and an automatic document feeder according to the present invention will be described with reference to the drawings. The document reading apparatus according to the present embodiment includes an automatic document feeder and an image reading apparatus, and is connected to the image forming apparatus.

(Configuration of document reader)
FIG. 1 is a cross-sectional view showing a configuration of a document reading apparatus according to an embodiment. The document reading device 500 includes an image reading device (reader) 200, an automatic document feeder (ADF) 100, and a controller unit 400 (see FIG. 4).

  FIG. 1 shows a state immediately after the document S is set on the document tray 30. The ADF 100 of the present embodiment is an ADF having a relatively short document conveyance path, that is, an ADF in which the conveyance distance from the post-separation sensor 12 to the document reading position is shorter than a predetermined distance. Specifically, since the transport distance is shorter than the shorter length (210 mm) of the A4 size which is mainly used, the document is read at the document reading position in the measurement by clock measurement of the transport motor during document transport. It is not possible to determine the length of the document feed direction until it arrives.

(Document feed processing from ADF)
A document image reading operation using the ADF 100 will be described. When a document image reading job by the ADF 100 is started, the scanner unit 209 moves to a position directly below the reference white plate 219, and a shading operation is performed.

  After the shading operation is performed, the scanner unit 209 moves to a position directly below the flow reading glass 201 and waits until the document reaches the reading position.

  2A, 2B, and 2C are diagrams illustrating a document reading operation. In the ADF 100, as shown in FIG. 2A (a), when a job is started, first, the paper feed roller 1 drops on the original surface of the original bundle S composed of a plurality of originals and starts to rotate. As a result, the uppermost document S1 of the document bundle is fed.

  When the ADF 100 feeds and transports the uppermost document S1 one by one from the document tray 30 on which the document bundle S is stacked, the documents other than the uppermost one document are transported from the document bundle S in an overlapping manner. The separation roller 2, the separation pad 8, and the sheet feeding roller 1 that regulate the sheet feeding / conveying are performed.

  The original S1 fed and conveyed by the paper feed roller 1 is separated into one sheet by the action of the separation roller 2 and the separation pad 8. This separation is realized by a well-known separation technique.

  As shown in FIG. 2A (b), the document S1 separated by the separation roller 2 and the separation pad 8 is conveyed to the registration roller 3 and abutted against the registration roller 3. As a result, a loop is formed on the leading end side of the document, and skew feeding in the conveyance of the document S1 is eliminated. A pre-document reading roller 4 is provided on the downstream side of the registration roller 3. A paper feed path for conveying the document S1 in the direction of the document flow reading platen glass 201 by the pre-document reading roller 4 is disposed.

  As shown in FIG. 2C, the document S1 sent to the paper feed path is sent to the pre-document reading roller 4 by the registration roller 3. Further, the original S1 passes through the pre-original reading roller 4 and is conveyed so as to pass the original reading position of the original flow reading platen glass 201 in the vicinity of the original reading platen roller 5.

  When the document is conveyed to the document reading position of the document flow reading platen glass 201, the lead sensor 14 detects the leading edge of the document in order to detect the document reading leading position. The ADF 100 determines the time from when the read sensor 14 is turned ON until the document reaches the document reading position of the document flow reading platen glass 201 as a driving motor for driving the pre-document reading roller 4 and the document reading platen roller 5 (see FIG. (Not shown).

  As described above, the ADF 100 predicts the timing at which the leading edge of the document reaches the document reading position on the document flow reading platen glass 201. At the predicted document leading edge arrival timing, the scanner unit 209 captures a scanned image on the document surface.

  As shown in (d) of FIG. 2B, when the ADF 100 detects the trailing edge of the document S1 with the post-separation sensor 12, the document presence / absence detection sensor 16 detects the presence or absence of the next document on the document tray 30. When the trailing edge of the document S1 passes through the document reading platen roller 5 and the roller 6 and is further conveyed, the trailing edge of the document S1 is detected by the paper discharge sensor 15. When the document trailing edge detection timing by the discharge sensor 15 is used as a trigger, and the document S1 is discharged from the discharge roller 7 to the document discharge tray 31 (see (e) of FIG. 2B), one side of one document The document reading and conveying sequence ends.

  The ADF 100 basically repeats document feeding, document image capture, and document ejection as described above until there is no document on the document tray 30 except when only the number of sheets set in the job setting is read. As shown in FIG. 2B (d), when the ADF 100 detects the absence of the original when the trailing edge of the original is detected by the post-separation sensor 12, the ADF 100 determines that the original being conveyed is the final original, and the final original is Wait until the document is discharged to the document discharge tray 31. When the final document is discharged to the document discharge tray 31, the ADF 100 stops the conveyance motor that is a driving source of each roller, and returns the paper supply roller 1 to the original position. Thereby, the document reading job is completed.

(Document feeding process when reading double-sided documents)
A description will be given of the conveyance of a document when reading both sides of a document. As shown in (a) to (c) of FIG. 2A and (d) and (e) of FIG. 2B, the document reading device 500 conveys the document S1 when reading the front side of the document, as in reading a single-sided document. Then, the skew correction is performed by the registration roller 3 and the sheet is conveyed to the paper discharge roller 7. At the end of the front side reading, after the discharge sensor 15 is detected to be OFF by the trailing edge of the document S1, the document reading device 500 further continues until the trailing edge of the document S1 reaches 18 mm before the discharge roller 7. The document is transported, and then transport of the document S1 is stopped (see (f) in FIG. 2C).

  Next, in order to read the back surface of the document S1, the document reading device 500 reverses the front and back of the document S1. As shown in (g) of FIG. 2C, the paper discharge roller 7 is rotated in the reverse direction while the original S1 is engaged with the paper discharge roller 7, and the paper discharge flapper 21 is switched. By driving the paper discharge roller 7 in the reverse direction, the document reading apparatus 500 conveys the document to the reversing path 20 (return conveyance path), abuts against the registration roller 3 located upstream, and performs skew correction. .

  Thereafter, the document reading apparatus 500 drives the registration roller 3 to separate the paper discharge roller 7 and stops driving the paper discharge roller 7. Here, the reason why the discharge roller 7 is separated and stopped is that when the document size is large, such as A3 size, the document is reversed with the trailing edge of the reversed document remaining on the discharge roller 7, and the back side This is because it is assumed that the leading edge of the document being read enters the paper discharge roller 7 again. In this case, if the paper discharge roller 7 is not separated, the paper discharge roller 7 causes a slip between the front end side and the rear end side of the document, and the paper discharge roller 7 is pressed in a state where a nip is formed. Then, a collision occurs between the leading edge and the trailing edge of the document being conveyed. For this reason, the paper discharge roller 7 is separated so that such a collision does not occur.

  As shown in FIG. 2C (h), when the leading edge of the document S1 passes through the pre-document reading roller 4, the document reading device 500 causes the document reading platen roller 5 to flow the document S1 again and move it to the reading glass 201. Then, the document reading apparatus 500 reads the back surface of the document S1 at the document reading position on the reading glass 201.

  As in the case of the front side reading, the document reading apparatus 500 is configured such that the conveyance motor that serves as the drive source of the document reading platen roller 5 determines the timing at which the leading edge of the document reaches the document reading position of the document flow reading glass 201 from the ON timing of the read sensor 14. It counts with the clock.

  As described above, the document reading apparatus 500 predicts the arrival timing of the document leading edge at the document reading position on the document flow reading glass 201, and the scanner unit 209 captures an image by scanning the document back surface at the predicted timing. Do.

  After the reading of the back side image of the original is completed, the original reading device 500 does not discharge the original to the paper discharge tray 31 as it is, but reverses the original using the reverse path 20 and discharges it again. This is because the document pages are discharged to the discharge tray 31 and when all the documents are read, the pages of the documents are arranged in the same order as the original document bundle S.

(Detection of document width and document length for document size detection)
In the ADF document size detection according to the present embodiment, a standard size such as an AB standard size or an inch standard size is detected. FIG. 3 is a diagram showing various sensors arranged on the document tray 30. The document tray 30 is provided with a guide regulating plate 18 that is slidable in the width direction of the stacked document bundle S in the width direction orthogonal to the document transport direction. In addition, a guide regulating plate document width detection sensor (not shown) for detecting the length of the document in the width direction (document width) is provided in conjunction with the guide regulating plate 18.

  When the user sets the document on the ADF, the guide regulating plate 18 manually clamps the document from both sides in the width direction so as to prevent the set document from being inclined and regulates the document. .

  When all the document bundles S are composed of documents of the same size, the document size of the document bundle S stacked on the document tray 30 is determined as follows. That is, from the document width information obtained from the guide regulating plate document width detection sensor and the document conveyance direction length information detectable by the tray size detection first sensor 10 and the tray size detection second sensor 11 on the document tray 30, The document size of the document bundle S can be determined. The tray size detection first sensor 10 and the tray size detection second sensor 11 are also referred to as a tray sensor 10 and a tray sensor 11, respectively. Details of the reading mode (same width / different width original mixed reading mode) of the original bundle S in which originals of different sizes are mixed will be described later.

(Reading process by the scanner unit)
The reader 200 optically scans a document placed on the document table glass 202 in the direction of arrow a (sub-scanning direction) shown in FIG. read.

  The ADF 100 also conveys the originals stacked on the original tray 30 one by one to the original reading position. On the other hand, the reader 200 moves the optical scanner unit 209 to the document reading position of the document flow reading glass 201, and reads the document being conveyed at that position.

  A document loaded on the ADF 100 or a document placed on the document table glass 202 is read by the optical system via the document flow reading glass 201 or the document table glass 202. This optical system includes a scanner unit 209 having a light source lamp 203 and a folding mirror 204, folding mirrors 205 and 206, a lens 207, and a CCD sensor unit 210. Image information read by the CCD sensor unit 210 is photoelectrically converted and input to the controller unit 400 (see FIG. 4) as image data.

  The reference white plate 219 is a white plate for creating white level reference data in the shading correction process. Immediately after the start of the document image reading job, the reader 200 moves the scanner unit 209 to a position immediately below the reference white plate 219 and reads the reference white plate to perform shading correction processing.

(Control system configuration)
FIG. 4 is a block diagram illustrating configurations of the ADF 100, the image reading apparatus 200, and the controller unit 400. The ADF 100 includes a control unit (hereinafter referred to as CPU) 300, a read only memory (hereinafter referred to as ROM) 301, a random access memory (hereinafter referred to as RAM) 302, an output port and an input port, which are central processing units.

  The ROM 301 stores a control program. The RAM 302 stores input data and work data. The output port is connected to a motor 303, a solenoid 306, a clutch 307, and the like that drive various conveying rollers. Various sensors 304 are connected to the input port. As various sensors 304, a lead sensor 12, a paper discharge sensor 13, a paper discharge sensor 15, a document width detection sensor 17, and the like are provided.

  The CPU 300 controls document conveyance according to a control program stored in a ROM 301 connected via a bus line. Further, the CPU 300 performs serial communication with the central processing unit (CPU) 321 in the image reading device (reader) 200 via the control communication line 351, and exchanges control data with the image reading device 200. . In addition, an image destination signal serving as a reference of the leading edge of the document image data is also notified to the image reading apparatus 200 through the control communication line 351.

  A CPU 321 in the image reading apparatus 200 controls the image reading apparatus 200. Connected to the CPU 321 are a ROM 322 for storing programs and a work RAM 323. The optical system motor drive unit 326 is a driver circuit for driving the optical system drive motor.

  A lamp 327 and a CCD sensor unit 210 are connected to the image reading apparatus 200. The CCD sensor unit 210 is provided with a color image reading CCD 211 and a CCD controller unit 212. The CPU 321 controls the optical system motor drive unit 326 and controls the CCD sensor unit 210 via the image processing unit 325 to perform image reading processing.

  In order to realize document conveyance, the CPU 321 instructs a sheet conveyance control command to the sheet conveyance control CPU 300 of the ADF 100 via a control communication line (communication line) 351. When a paper conveyance control command is instructed, the CPU 300 monitors various sensors 304 installed in the conveyance path and drives a conveyance motor 303, a solenoid 306, and a clutch 307, which are loads, to perform paper conveyance control. .

  As described above, the CPU 321 performs document conveyance control by the ADF 100 and image reading control in the image reading apparatus 200.

  The document interval correction processing unit 324 corrects the conveyance interval (distance between the preceding document and the succeeding document) of the succeeding document with respect to the preceding document. The reflected light image of the original image formed on the CCD sensor unit 210 via the lens 207 is converted into digital image data. The converted digital image data is further subjected to various image processing such as shading correction processing and unnecessary image removal processing for detecting and removing streak images on the image data by the image processing unit 325. The image data that has been subjected to various types of image processing is written into the line image memory unit 329.

  The data written in the line image memory unit 329 is sequentially transmitted to the controller unit 400 through the controller interface image communication line 353 including the image transfer clock signal line.

  Further, the timing of the image destination signal serving as the reference of the leading edge of the document image data is adjusted by the CPU 321 and notified to the controller unit 400 through the controller interface control communication line 352. Similarly, the timing of the image destination signal notified from the ADF 100 via the communication line 351 is adjusted by the CPU 321 in the image reading apparatus 200 and notified to the controller unit 400 via the controller interface control communication line 352.

  The controller unit 400 includes a control unit 401, an image control circuit 402 for zooming and rotation, a correction circuit 403, an image memory 404, and an operation unit 405, and includes an image reading device 200 and an automatic document feeder 100. (Document reading apparatus) 500 is controlled as a whole. The user can select the mixed document reading mode from the operation unit 405. When the mixed document reading mode is selected, the user can select whether the document has the same width or the mixed document of different widths. Has been.

  The CPU 321 controls the image processing unit 325 connected to the control bus line. Further, the CPU 321 transmits a control signal from the control communication line 354 to the CCD sensor unit 210 via the image processing unit 325 to control the CCD sensor unit 210.

  In the process of scanning the original image by the CCD sensor unit 210, an analog image signal is output to the CCD controller unit 212 via the communication line 213 for each line read by the color image reading CCD sensor 211.

  The CCD controller unit 212 converts the analog image signal into digital image data. The digital image data is transmitted from the image data information communication line 355 including the image transfer clock signal line to the controller unit 400 via the line image memory unit 329.

  After image processing such as scaling / rotation is performed by the image control circuit 402, an image signal (image data) is transmitted to the correction circuit 403. The correction circuit 403 performs correction processing on the image signal and writes it in the image memory 404. The image data that has been subjected to the various processes described above is handled as a read image of a document.

(Automatic paper selection function)
In the automatic paper selection function, the recording medium used for image formation by the document reading apparatus 500 based on the size of the recording medium, the size of the document, and the reading magnification stored in the paper feed cassette of the image forming apparatus (not shown). This is a function to select automatically. In this case, the reading magnification is set by the user.

  For example, when an A4 size document is set in the ADF 100 in a landscape orientation (the landscape orientation is A4R) so that the conveyance direction side is long, and the user sets the reading magnification to 141% and reads the A4R size document, The document is enlarged and read at 141%. As a result, the output size of the image of the read original is A3 size. Therefore, if the image forming apparatus has an A3 size recording medium, the A3 size recording medium is automatically selected, and the A3 size recording medium is selected. To be copied.

  As described above, the automatic paper selection function is a function that is not established unless the document size is determined before the reader 200 and the ADF 100 read the document image and the controller unit 400 is notified of the document size (output image size) information. .

(Automatic magnification selection function)
The automatic magnification selection function is a function that is mainly used when a document bundle in which documents of different sizes are mixed is output on a uniform sheet of a specific size. For this reason, the document reading apparatus 500 automatically determines the document reading magnification so as to match the size of the recording medium on which an image is formed by the image forming apparatus, and reads the document at the determined magnification. This reading magnification is determined by original size information for each original of the original bundle S set in the reader 200 or ADF 100, and size information of a recording medium selected by the user as a recording medium used for image formation.

  Thus, the automatic magnification selection function is a function for automatically selecting the reading magnification from the document size information and the recording medium size information.

  For example, a case where an original to be copied is A3 size and an image of the read original is copied to an A4 size recording medium is taken as an example. In this case, the image data cannot be copied to the A4 size recording medium unless the image data of the original read by the CCD sensor unit 210 in the reader 200 is reduced or rotated.

  Therefore, when automatically calculating the reduction ratio, it is necessary to determine the document size before the document reading device 500 reads the document. Furthermore, before reading the document, it is necessary to prepare for image processing by the controller unit 400, such as rotation processing that is processing after scanning. .

(Same width / different width original mixed reading mode)
Next, the same width / different width original mixed reading mode will be described. The automatic paper selection function and the automatic magnification selection function described above are functions that are mainly used when the original mixed reading mode for detecting the original size one by one is set for an original bundle of originals of different sizes. is there.

  Conventionally, in order to determine the document size for each document, the document reading device 500 conveys the document without reading the image of the document by using an inversion path that is used to invert the document at the time of duplex scanning. However, the length in the document conveyance direction (document length) was detected during conveyance. Then, the document reading apparatus 500 determines the document size from the detected document length and document width, and after determining the document size, the document reading device 500 uses the reverse path again, and the reading target surface is again set to the reading position. Until it came to, it was reversed twice (idle rotation).

  As described above, if the extra idle rotation (reversal) is executed twice for each original in order to determine the original size, the reading productivity in the setting of the original mixed reading mode is lowered.

  Therefore, in the present embodiment, when determining the document size, the document reading apparatus 500 temporarily determines the document size by predicting the document size from information obtained about the conveyed document, and the provisionally determined document size. If is correct, continue reading the document.

  On the other hand, if the tentatively determined document size is different from the actual measurement result, the document reading apparatus 500 determines that the tentatively determined document size is wrong, and rotates the document idly to set the correct document size. Perform detection. When the provisional determination of the document size is performed, even if the provisionally determined document size is incorrect and it is necessary to perform idling, the document reading apparatus 500 can reduce the idling time so that the idling time is shortened as will be described later. Is temporarily determined.

  Next, a process until the document size at the time of document reading is determined in the same width / different width document mixed reading mode will be described. The same width original mixed reading mode and the different width original mixed reading mode are collectively referred to as an original mixed reading mode.

(Information obtained from the transported document)
FIG. 3A described above shows the ADF 100 with the transport cover 32 closed. FIG. 3B shows the ADF 100 with the transport cover 32 opened.

  A pair of conveyance guide regulating plates 18 (regulating members) that regulate both ends of the bundle of documents stacked on the document tray 30 in the width direction are provided on the document tray 30 in the width direction as indicated by arrows f in FIG. It is movable. The position of the conveyance guide regulating plate 18 is detected by a first detection unit (sensor) (not shown). Further, the conveyance guide regulating plate 18 is normally used by being moved by the user to a position corresponding to the width of the document bundle.

  As described above, the paper feed roller 1 feeds the originals by separating them from the original bundle one by one. The separation roller 2 separates the uppermost document and the document below it so that a plurality of documents are not conveyed in an overlapping manner. The registration roller 3 corrects the skew of the document (sheet) being conveyed and conveys the document at a predetermined timing.

  The document presence / absence detection sensor 16 detects the presence / absence of a document on the document tray 30. The tray size detection first sensor 10 and the tray size detection second sensor 11 determine the length in the document transport direction when a document is set on the document tray 30.

  Normally, when a document bundle made up of documents of the same size is set on the document tray 30, the document size can be determined from the width of the document bundle and the length in the conveyance direction if the document size is a fixed document size. . That is, the standard document size is determined from the document width information detected by the conveyance guide regulating plate 18 and the document length information detected by the tray size detection first sensor 10 and the tray size detection second sensor 11. Is possible. This is because when all the originals have the same original size, the information detected by these sensors is common to all the originals regarding the original width and original length.

  On the other hand, when a document bundle in which documents of different document widths and document lengths are mixed is set on the document tray 30, the document width is detected depending on the width of the document having the maximum width in the document bundle. Become. The length in the document conveyance direction is detected by the tray size detection first sensor 10 and the tray size detection second sensor 11 depending on the length of the document having the maximum document conveyance direction length in the document bundle. Will be.

  FIG. 5 is a table showing the relationship between the document size and the ON / OFF of the corresponding tray size detection first sensor 10 and tray size detection second sensor 11. This table is stored in the ROM 322. FIG. 4A shows the case of a standard size of AB standard (size for AB). FIG. 4B shows a case of a standard size (for inch) of the inch standard. As shown in this table, the tray size detection first sensor 10 and the tray size detection second sensor 11 (hereinafter also referred to as both sensors) are turned ON / OFF according to the document size standard.

  For example, in the case of a document bundle in which the first sheet is an A3 document and the second sheet is a B4 document, according to the table of FIG. 5A, the tray size detection first sensor 10 and the tray size detection second sensor 11 are 1 Both of the first A3 document and the second B4 document are turned ON when feeding is started.

  For this reason, immediately after the start of feeding the first document, the document length is temporarily determined to be a large size series (A3 / B4, not A4 / B5) based on detection information from both sensors. The size of the original document (A3 original document) is actually measured, and is determined to be a large size series.

  In addition, immediately after the start of feeding the second original, immediately after the start of feeding the second original, the original length is temporarily determined as a large size series based on the detection information of both sensors, and then the actual length is the same as the first original. The size of the original (B4 original) conveyed to the printer is actually measured, and the large size series is determined.

  As described above, even when different document sizes are combined, depending on the combination pattern and document order, the state of both sensors at the start of feeding and feeding may be directly applicable to the length of the document being conveyed. . That is, there is a combination of A3 / B4, which is a large size series at the time of provisional judgment by both sensors and a large size series at the time of actual measurement.

  Therefore, for the above-described original length, a combination of originals (specifically, a combination of the A3 original for the first sheet and the B4 original for the second sheet) in which the information on the original length at the start of paper feed conveyance is correct. Think. Details of a method for detecting the correct document width of each document by this combination will be described later.

  When the correct original width is detected by the time the leading edge of each original reaches the original reading position, such as A3 width (297 mm) for the first original and B4 width (257 mm) for the second original, The following can be considered. That is, the provisional document size is determined from the document length information detected at the start of paper feed and the correct document width information. Further, it is assumed that the document size actually measured immediately after the start of reading and the provisionally determined document size are equal due to the parallel processing.

  In the case of this combination, it is assumed that the tentatively determined document size finally becomes the correct document size, so that idling rotation for rereading the document is not necessary. Since the leading edge of the document has reached the reading position before the document size is determined, the image of the document based on the temporary size is read.

  On the other hand, when the first sheet is an A4 size document and the second sheet is a B5 size document, according to FIG. 5A, the tray size detection first sensor 10 and the tray size detection second sensor 11 are both OFF and are in the same detection state. become. In this case, the small size series is determined.

  Therefore, for each document, if the document width size during conveyance is detected as either A4 width (297 mm) / B5 width (257 mm) before the leading edge of the document reaches the document reading position, the width size is detected. At that time, the document size is provisionally determined. It is assumed that the temporarily determined size is equal to the document size actually measured immediately after the start of reading by parallel processing. Details of the method for detecting the correct document width will be described later.

  Therefore, in the case of the combination of A4 / B5 as well as in the case of the combination of A3 / B4, it can be assumed that the document size temporarily determined until reaching the document reading position finally becomes the correct document size. For this reason, even in this combination, idle rotation for rereading the document is not necessary. Also in this case, since the leading edge of the document has reached the reading position before the document size is determined, the document image reading based on the temporary size is performed.

  As described above, depending on the combination of documents, idle rotation for re-reading the document is not necessary, so that the reading productivity in the mixed document reading mode for reading documents of different sizes is improved.

  On the other hand, if the first document is an A4 size and the second document is a B4 size document bundle, the long document length of the two A4 size and B4 size documents is the B4 size. . Therefore, both the tray size detection first sensor 10 and the tray size detection second sensor 11 arranged on the document tray 30 are turned on according to the length of the B4 size.

  According to the table of FIG. 5A, the first A4 document is also predicted to be a large size series (A3 or B4). As a result, in the case of the combination of A4 document / B4 document, even if the correct document width is specified at the time of document conveyance, the provisional document size is as follows. That is, when predicted from the width information and the document length based on the detection information of the tray size detection first sensor 10 and the tray size detection second sensor 11, the first document size is provisionally determined to be A3 size. Therefore, the predicted temporary document size is different from the actually measured document size.

  In this case, when the provisional document size (A3) provisionally determined by the prediction is different from the correct document size (A4) by actual measurement, the document is reversed twice using the reversal path. However, since an A4 size document having a document length shorter than the A3 size is idled, the time required for idling is considerably shorter than when an A3 size document is idly rotated.

  As described above, even in the mixed document reading mode, depending on the combination of different document sizes, the document width is specified, and the information of the tray size detection first sensor 10 and the tray size detection second sensor 11 is taken into consideration, so that the document can be reproduced. The idle rotation for reading is eliminated, and the reading productivity is remarkably improved as compared with the conventional case.

  Furthermore, the time can be shortened by applying the following device so that the idle rotation time is minimized when the document is read again. In other words, the provisional document size is set to the maximum of the assumed sizes based on the document width determined when the document is conveyed and the determination information based on ON / OFF of the tray size detection first sensor 10 and the tray size detection second sensor 11. It is determined. As described above, determination information by ON / OFF includes large size series (A3 / B4 / LDR / LGL, etc.), middle size series (A4R / B5R / LTRR, etc.), small size series (A4 / B5 / LTR / STMT, etc.). Etc.).

  If the determined provisional document size is different from the maximum size, the idling time for re-reading should be at least the idling rotation time for a size smaller than the provisionally determined maximum size.

  When the first original is A4 size and the second original is B4 size, as described above, the tray size detection first sensor 10 and the tray size detection second sensor 11 have the B4 size length. In response, both are turned on.

  When the A4 width (297 mm) is determined during conveyance of the first document, the tray size detection first sensor 10 and the tray size detection second sensor 11 are in the ON state. For this reason, the A3 size, which is the maximum length at which the tray size detection first sensor 10 and the tray size detection second sensor 11 are turned on with a width of 297 mm, is determined as the temporary document size.

  As described above, the reason why the maximum size is temporarily determined as a prediction is that if the prediction is out of order, the reversal path is used to re-read the original and preparation for re-reading is performed. This is to shorten the idling time as much as possible. For example, when comparing the idle rotation time when conveying an A4 size document and an A3 size document, the total idle rotation time is shortened by about half because the A4 document is shorter in the conveyance direction.

  As described above, the size is predicted so that the conveyance time of the idle rotation of the original can be shortened even if the prediction is not satisfied. That is, as a prediction, the provisional document size is the largest of the assumed sizes based on judgment information based on ON / OFF of the tray size detection first sensor 10 and the tray size detection second sensor 11 and document width information by conveyance. Will be determined.

  As described above, when the temporarily determined document size deviates, idle rotation corresponding to at least a size smaller than the temporarily determined size is performed. In other words, the idle rotation time for the A4 size when the A4 document is estimated to be A3 original is larger than the idle rotation time for the A3 size when the A3 original is predicted to be A4 size. It is short.

(Original reading operation)
Next, an original reading operation of the original reading apparatus 500 using the ADF 100 will be described. FIG. 6 is a diagram showing a state in which a document bundle S in which documents of different sizes are mixed is set on the ADF 100. The figure (a) shows the state seen from the front, and the figure (b) shows the state seen from the upper part of the figure (a).

  Here, as an example, a case where an A4 size document is set on a B4 size document (the first sheet is A4 size and the second sheet is B4 size) is shown. In FIG. 5B, the document indicated by the thick line frame is a B4 size document. It is assumed that different widths are set in the mixed document reading mode. On the other hand, the document indicated by the dotted frame is A4 size. All the documents are set close to the conveyance guide regulating plate 18 on the back side (upper side in FIG. 6B). The A4 original is set with the long side (297 mm) as the width direction orthogonal to the feed direction.

  The conveyance when the long side of the document is set so as to be parallel to the document conveyance direction is referred to as R-direction conveyance. In this case, if the document size is, for example, an A4 size document, it will be referred to as an A4R size.

  In this example, since an A4 size document is set, the conveyance guide regulating plate 18 is in a state of being widened to the maximum width. Further, since a B4 size document is set on the document tray 30, both the tray size detection first sensor 10 and the tray size detection second sensor 11 are in an ON state.

  When the mixed document reading mode (different width) is not set, the standard document size is determined based on the document width detected by the conveyance guide regulating plate 18 and the information of the tray size detection first sensor 10 and the tray size detection second sensor 11. Which original size is determined. That is, from the table in FIG. 5, the size in the document transport direction is one of a large size series (A3 / B4 / LDR) / middle size series (A4R / B5R / LTRR) / small size series (A4 / LTR or less). Is detected. Based on these pieces of information, it is possible to determine which document size is the standard size.

  On the other hand, when the mixed document reading mode is set, the document size cannot be specified only by setting the document bundle S on the document tray 30, and the size may be different for each document. You must specify the document size one by one.

  Therefore, as described above, the document reading apparatus 500 detects the following information (i) and (ii) immediately before feeding from the document tray 30 in order to provisionally determine the document size, and the document size: Used to predict

(I) ON / OFF information of the tray size detection first sensor 10 and the tray size detection second sensor 11 in the document tray 30 immediately before the document feeding conveyance (ii) Document width information detected by the conveyance guide regulating plate 18 8 and FIG. 9 are flowcharts showing the document reading operation procedure. The control program is stored in the ROM 322 in the image reading apparatus 200 and is executed by the CPU 321 in the image reading apparatus 200 in accordance with a request instruction from the control unit 401 in the controller unit 400.

  After the document bundle S is set on the document tray 30 by the operator, the CPU 321 starts a reading job such as copying using the ADF 100 (step S1).

  The CPU 321 determines whether or not the reading mode set by the operator's operation is the mixed document reading mode (step S2). Information on the mixed document reading mode set by the operation of the operator is notified from the control unit 401 to the CPU 321.

  When the mixed document reading mode is not set, that is, in the non-mixed document reading mode, basically, all the document bundles S have the same document size. Accordingly, when the document size of the first document is determined, the second and subsequent documents are read according to the document size determined for the first document.

  As a result of the determination in step S2, in the non-mixed document reading mode, the CPU 321 waits for a document feed start request notification from the control unit 401 (step S21). When a document feed start request is notified, the CPU 321 determines whether or not it is the first document (step S22).

  If it is the first document, the CPU 321 detects the document width from the guide width of the transport guide regulating plate 18 immediately before the start of feeding by the guide regulating plate document width detecting sensor (step S23). Here, in the non-mixed original reading mode, the original reading apparatus 500 operates on the assumption that all the originals of the original bundle S have the same original size, so that the guide width detected by the conveyance guide regulating plate 18 is the same. The document width is determined as it is.

  Further, the CPU 321 detects the document length from the information detected by the tray size detection first sensor 10 and the tray detection second sensor 11 using the table shown in FIG. 5 (step S24). Here, as in the case of the document width, since the document reading apparatus 500 operates on the assumption that all the documents in the document bundle S have the same document size, the document lengths detected by these sensors are all the same. This applies to the original length of the original.

  The CPU 321 determines a standard document size from the detected document width and document length (step S25). The CPU 321 starts document feeding with the document size determined (step S26). After starting the document feeding, the CPU 321 notifies the control unit 401 of the determined document size (step S27).

  In preparation for various image processing to be performed on a document image to be read from now on, the control unit 401 calculates magnification in a scaling process, sets a reading range, and sets an image memory based on document size information notified from the CPU 321. For example, the use area 404 is secured. When the image reading preparation is completed, the control unit 401 issues a document reading start request for the document being conveyed.

  When receiving a document reading start request from the control unit 401, the CPU 321 starts reading a document (step S28). That is, the CPU 321 instructs the CPU 300 in the ADF 100 to start reading via the control communication line 351.

  The CPU 321 waits until the reading of the document image is completed (step S29). When the reading ends, the CPU 300 notifies the CPU 321 of the end of reading via the control communication line 351. When the reading of the document image is completed, the CPU 321 determines whether or not the document whose reading has been completed is the final document (step S30).

  If it is not the final document, the CPU 321 returns to the process of step S21 and waits for a notification of a request to start feeding the next document in order to start reading the next document. When the notification of the request for starting the feeding of the next original arrives, the CPU 321 performs the process of step S22. In the processing of step S22, since the second and subsequent originals are not mixed loading settings, the operation is performed on the assumption that all the second and subsequent originals have the same original size as the first original. Therefore, the CPU 321 skips the processes of steps S23 to S25 for determining the document size, and proceeds to the process of step S26. Then, the process from the document feeding start process in step S26 to the document image reading end process in step S29 is continuously performed.

  In step S30, when there is no original and the original that has been read is the final original, the CPU 321 executes a post-processing operation (step S31), and ends the original reading operation in the non-mixed original reading mode.

  Next, a case where a document reading job is executed with the document mixed mode setting (different width) will be described. Here, as a first example, a description will be given assuming a combination of a bundle of documents S in which the first document is an A4 size document and the second document is a B4 size document.

  When the mixed document reading mode is set in step S2, that is, when the mixed document reading mode information is notified from the control unit 401 to the CPU 321, the CPU 321 waits for a document feed start request notification from the control unit 401. (Step S3).

  When notified of the document feed start request, the CPU 321 detects the guide width of the conveyance guide by the conveyance guide restriction plate 18 by the guide restriction plate document width detection sensor (step S4). Further, the CPU 321 detects the document length by the tray size detection first sensor 10 and the second sensor 11 (step S5). The process in step S5 is an example of a first document length detection unit.

  In this example, since the first document size is A4 size and the second document size is B4 size, the maximum document width is 297 mm of A4 size, and the maximum document length is 364 mm of B4 size. is there. As information detected in the B4 size document, both the tray size detection first sensor 10 and the tray size detection second sensor 11 are turned on. Accordingly, it is detected from both sensor information that the document bundle S includes a large-size document.

  In response to the document feed start request, the CPU 321 starts feeding the first document (step S6). When the feeding of the first document is started, the CPU 321 checks whether or not the post-separation sensor 12 is turned on by the leading edge of the document (step S7). If not, the CPU 321 returns to the process of step S7 and waits until the sensor 12 after separation is turned on. Information such as ON / OFF of the post-separation sensor 12 is notified from the CPU 300 to the CPU 321 via the control communication line 351.

  Here, the reason why the separation sensor 12 is turned on is to measure the period from the ON timing of the separation sensor 12 to the OFF timing of the separation sensor 12 by the timer clock of the CPU 321. That is, the actual length of the original is measured by measuring the time required for the post-separation sensor 12 to pass from the front end to the rear end of the original.

  When the CPU 321 detects that the post-separation sensor 12 is turned on, it starts actual measurement of the document length (step S8). The CPU 321 further detects whether or not the document has been conveyed and has reached the registration roller 3 (step S9). If the document has not reached the registration roller 3, the CPU 321 repeats the process of step S <b> 9 until the document reaches the registration roller 3. Then, the leading edge of the document is abutted against the registration roller 3 and is temporarily stopped to correct the skew during document conveyance.

  FIG. 10 is a view showing a state in which the leading edge of the first document is abutted against the registration roller 3. The figure (a) shows the state seen from the front, and the figure (b) shows the state seen from the upper part of the figure (a). As described above, in the example of this combination (first example), the width information detected by the conveyance guide regulating plate 18 is A4 size document width which is the maximum document width in the document bundle S, that is, A document width of 297 mm is detected.

  On the other hand, in the mixed document reading mode (different width) setting, it cannot be immediately determined that the width detected by the transport guide regulating plate 18 is the width of the document being transported. This is because in this combination example (first example), a B4 size document may be fed.

  Therefore, in the present embodiment, both the detection information of the document width detection sensor 17 and the information of the guide width of the conveyance guide regulating plate 18 that are juxtaposed in four locations near the registration roller 3 are used to convey the document being conveyed. The width is determined.

  When combining originals of different original sizes, such as A4 size originals and B4 size originals, when setting the originals on the original tray 30, the originals are set against the back side of the conveyance guide regulating plate 18. . At the timing when the leading edge of the document reaches the vicinity of the registration roller 3, the document is detected by some of the document width detection sensors 17 installed at four positions. In other words, the position of the end in the width direction of the document is detected by determining which of the four document width detection sensors 17 detects the document and which sensor does not detect the document. An assumed document size is determined from the detected end position. These document width detection sensors 17 function as a second detection unit that detects the position of one end in the document width direction.

  In this embodiment, when a document is set in a state where it abuts against the back guide of the conveyance guide regulating plate 18, the width of the conveyance guide regulating plate 18 and the number of detections of the document width detection sensor 17 are the document size and the document size. As related, four document width detection sensors 17 are arranged. FIG. 11 is a table showing the document size assumed from the width of the conveyance guide regulating plate 18 and the number of detections of the document width detection sensor 17. This table is stored in the ROM 322.

  The transport guide regulating plate 18 is configured such that the regulation of the main scanning width is variable based on the center reference in the width direction (main scanning direction). Accordingly, the width of the conveyance guide regulating plate 18 varies according to the document size. Further, the detection state of the document width detection sensor 17 through which the document passes during conveyance changes according to the width of the conveyance guide regulating plate 18.

  The CPU 321 performs conveyance based on the table of FIG. 11 based on the width information detected by the conveyance guide restricting plate 18, the number of detection information of the four document width detection sensors 17, and the destination information of the AB size / inch size of the document size. The width size of the document inside is determined (step S10).

  As described above, with respect to the document currently being conveyed, several size candidates are assumed from the detected document width information based on the table of FIG. That is, the CPU 321 functions as candidate acquisition means for acquiring document size candidates. In this case, since the first document is determined to have an A4 size width, a candidate of A4 size or A3 size is assumed.

  Of these candidates, the large table is further retrieved from the table of FIG. 5 based on the document length information, that is, the ON / OFF information of the tray size detection first sensor 10 and the tray size detection second sensor 11 immediately before the start of feeding. It is detected that the document is of a size series.

  Therefore, the CPU 321 tentatively determines the assumed maximum size as the document size of the document being conveyed in consideration of the document length information (step S11). That is, the CPU 321 functions as a temporary size determining unit. In this example (first example), the A3 size is provisionally determined as size information for the first document. In step S <b> 11, the CPU 321 notifies the control unit 401 of document size information that has been provisionally determined. The control unit 401 prepares for internal image processing based on the provisionally determined document size information.

  Preparations for image processing include, for example, preparations such as calculation of a reading magnification for an automatic magnification selection function and securing a use area of an image memory. As soon as these preparations are completed, the control unit 401 notifies the CPU 321 of a document reading request.

  Upon receiving the document reading request notification, the CPU 321 starts reading the document when the leading edge of the document reaches the document reading position (step S12). Thereafter, the CPU 321 waits until the post-separation sensor 12 is turned off during reading of the document (step S13). By detecting that the post-separation sensor 12 is OFF, the time from when the post-separation sensor 12 is turned on until it is turned off is measured by the timer clock of the CPU 321. Note that the position of the post-separation sensor 12 corresponds to the detection position.

  Based on the measurement result, the CPU 321 measures the document length (second document length detection means), and determines the correct document size from the document length and document width obtained by this measurement (step S14). That is, the CPU 321 functions as an actual size determining unit. Here, the correct document size is determined to be A4 size together with the already determined document width information.

  The CPU 321 checks whether or not the correct document size based on the actual measurement result matches the document size provisionally determined by the prediction (step S15). When it is confirmed that they do not match, the CPU 321 executes a reread sequence in order to reread the original with respect to the currently read original (step S20). Thereafter, the CPU 321 proceeds to the process of step S18. In this example (first example), the size of the first document is the A4 document size, but since it is provisionally determined to be the A3 size, the prediction is off. Therefore, a re-reading sequence is executed for the document currently being read in order to re-read the document.

  On the other hand, when it is confirmed in step S15 that the correct document size based on the actual measurement result matches the original document size temporarily determined by the prediction, the CPU 321 notifies the control unit 401 of the actual measurement result (step S16).

  Then, the CPU 321 waits until the current document reading is finished (step S17). When the document reading ends, the CPU 321 determines whether or not the read document is the final document (step S18). If it is not the final document, the CPU 321 returns to the process of step S3.

  On the other hand, if it is the final document, the CPU 321 executes a predetermined post-processing operation (step S19), and ends this processing.

  Note that, as in this case, when the prediction is not correct, the CPU 321 does not notify the control unit 401 of the presence / absence information of the next document. The reason for this is that when the next document information is notified to the control unit 401, an extra reading such as canceling these processes when a reread occurs in response to a preparation process for the next document started inside the controller unit 400. This is because there is a high possibility that the repair process will occur. In other words, this process is to avoid generating extra time for the re-reading operation.

  Further, even if the document reading operation based on the temporarily determined size is completed, if the prediction is not satisfied, the CPU 321 does not notify the control unit 401 of the completion of reading. The reason for this is that if rereading occurs in response to processing that uses a reading end notification as a trigger event, there is a high possibility that extra repair processing such as canceling these processing will occur. In other words, this process is to avoid generating extra time for the re-reading operation.

  Therefore, as described above, the CPU 321 notifies the control unit 401 of the presence / absence information of the next document only in the case where the correct document size of the document being conveyed is found and the prediction is not deviated.

  FIG. 12 is a flowchart showing the document reread sequence in step S20. First, the CPU 321 notifies the control unit 401 that prediction has been lost as a result of actual measurement (step S41). The CPU 321 causes the ADF 100 to perform document reversal processing (idle rotation) using the reversal path 20 in order to read the same document surface again (step S42). The idle rotation executed at this time is the same as the idle rotation for the document reversing process at the time of duplex conveyance. The control unit 401 that has been notified that the prediction has been lost performs a cancel process on the page that is currently being read, discards the original image data information, and prepares to receive original image data information by rereading.

  When the CPU 321 causes the ADF 100 to execute document reversal processing (idle rotation processing) twice and detects that the leading edge of the document to be read has reached the registration roller 3, it determines that preparation for rereading the document is complete. The CPU 321 waits until preparation for rereading the original is completed (step S43), and when preparation for rereading the original is completed, the controller 401 is notified of completion of preparation for rereading the original (step S44). At this time, A4 size information which is the correct document size and presence / absence information of the next document, that is, document presence information is notified in this example (first example).

  When the CPU 321 receives a request for rereading the correct document size from the control unit 401, the CPU 321 rereads the document with the correct document size (step S45). Then, the CPU 321 waits until the rereading of the document is completed (step S46). The CPU 321 notifies the control unit 401 of the normal completion of the rereading of the document when the rereading of the document is completed (step S47). Then, the CPU 321 returns to the main process.

  In the main process, when the document re-reading sequence ends, the CPU 321 determines in step S18 whether the document whose re-reading has been completed is the final document. If it is determined that the document is the final document, the CPU 321 ends the document reading operation. If there is a next document, the CPU 321 returns to the process of step S18 and waits for a document feed start request notification from the control unit 401.

  When the next document feed start request is notified, in this example (first example), the CPU 321 immediately starts feeding the B4 document, which is the second document.

  The document size is determined for the second document as well as the first document. Since the second original is B4 size, both the tray size detection first sensor 10 and the second sensor 11 are both turned on. The guide width of the conveyance guide is A4 width (297 mm), like the first document. On the other hand, as the detection information of the document width detection sensor 17, three places are turned ON. From the detection information of the document width detection sensor 17 and the guide width information (297 mm), it is determined that the document width information is B4 size width (257 mm).

  As described above, several size candidates are assumed in the document width information detected by using the table of FIG. 11 for the document currently being conveyed. In this case, since it is determined that the second sheet has a B4 size width, candidates for the B4 size and the B5 size are assumed. Among these candidates, based on the document length information, that is, the ON / OFF information of the tray size detection first sensor 10 and the tray size detection second sensor 11 immediately before the start of feeding, the large size is obtained from the table of FIG. It is detected that it is a series.

  Accordingly, in step S10, the CPU 321 considers the document length information and temporarily determines the assumed maximum document size as the document size of the document being conveyed. That is, the second document size is provisionally determined to be B4 size.

  For the second original, the original length is measured in the same manner as the first original. In step S14, the correct document size is determined to be B4 size together with the already determined document width information. For the second document, the document size provisionally determined by the prediction is predicted to be the B4 size, and therefore matches the document size obtained by actual measurement. Therefore, the rereading of the document does not occur.

  In step S16, the CPU 321 notifies the control unit 401 that the prediction is correct as a result of the actual measurement, and performs an operation of continuously reading the second original. When notifying the control unit 401, the presence / absence information of the next original is notified at the same time. In this example (first example), since there is no third original, information on the absence of the next original is notified.

  In step S17, the CPU 321 waits until the reading of the second document is completed. When the reading of the second document is completed, the CPU 321 determines in step S18 whether the document that has been read is the final document. If it is determined that the document is the final document, the CPU 321 executes predetermined post-processing in step S19, and ends this processing.

(When the first original is B4 size and the second original is A4 size)
Next, as a second example, a case where the first original is a combination of B4 size and the second original is A4 size will be described.

  Since the first document size is B4 size, both the tray sensor 10 and the tray sensor 11 immediately before the start of feeding are turned on. Further, since the B4 size and the A4 size are combined, a large A4 width (297 mm) is detected as the guide width of the conveyance guide regulating plate 18. Further, three locations are detected as detection information of the document width detection sensor 17 detected during conveyance.

  Accordingly, the maximum size assumed in the prediction when the registration roller 3 is abutted is the B4 size. B4 size is provisionally determined as the document size.

  Actually, since the first document is B4 size, it is continued without being reversed and feeding of the next document is started.

  Since the document remaining on the document tray 30 is an A4 size document when the feeding of the next document is started, both the tray sensor 10 and the tray sensor 11 immediately before the start of feeding are turned off.

  For the second original, both the tray sensor 10 and the tray sensor 11 immediately before the start of feeding are OFF. Further, the A4 width (297 mm) is detected as the guide width of the conveyance guide regulating plate 18. Further, four locations are detected as detection information of the document width detection sensor 17 detected during conveyance.

  Therefore, from these pieces of information, the provisional size predicted when the registration roller 3 is abutted is the A4 size that is the assumed maximum size.

  Here, as described above, compared to the case where the first sheet is an A4 size document and the second sheet is a combination of B4 size documents, the tray sensor 10 and the tray are fed when feeding the second A4 size document. The detection information of the sensor 11 is different. For this reason, the maximum size assumed in the prediction is the A3 size in the previous example (first example), and the A4 size in the present example (second example).

  Actually, since the second document size is A4 size, the document size of the second document is correctly detected by actual measurement. As a result, in this example (second example), the reading operation is completed without any inversion in both the first and second sheets.

  As described above, according to the document reading apparatus of the present embodiment, when the temporary document size and the actual document size are equally predicted, it is possible to continue reading the image of the document without re-reading. On the other hand, even if the prediction is deviated, since the document size is shorter in the transport direction than the maximum document size, the time for idling the document via the reverse path can be shortened. Therefore, the reading productivity in the mixed document mode is improved, and the usability is improved for the user.

  Further, it can be applied to a document reading apparatus having a short conveyance path, and the apparatus can be miniaturized. In addition, when rereading occurs in the preparation process for the next original, it is possible to avoid the possibility that an extra repair process such as canceling these processes will increase. Therefore, no extra time is required for the re-reading operation.

  In the mixed document reading mode (same width), the timing at which the correct width of the document can be detected is only faster than in the mixed document reading mode (different width), and other controls are the same as in the case of the different width. It is.

  The present invention is not limited to the configuration of the above-described embodiment, and any configuration can be used as long as the functions shown in the claims or the functions of the configuration of the present embodiment can be achieved. Is also applicable.

  For example, in the above-described embodiment, the reading unit (CCD sensor unit) that reads an image of a document is provided in the image reading device 200. However, the reading unit is provided in the automatic document feeding device, and the automatic document feeding device is a document. The image may be read while conveying the image.

  In the above embodiment, the document reading operation shown in FIGS. 7, 8, and 9 is executed by the CPU 321 in the image reading apparatus 200, but is executed by the CPU 300 in the automatic document feeder 100. Also good. As a result, even when the automatic document feeder is connected to another image reading device, the same control can be performed.

  Examples of the image forming apparatus to which the document reading apparatus of the present invention is connected include an electrophotographic image forming apparatus and an electrostatic recording image forming apparatus. Of course, such an image forming apparatus may be an original printing apparatus, a facsimile apparatus having a printing function, a multifunction peripheral (MFP) having a printing function, a copy function, a scanner function, and the like.

  Further, the present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device.

  In addition, the shapes of the component parts described in the above embodiment, the relative arrangement thereof, and the like should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions, and the scope of the present invention is described above. It is not limited only to what is illustrated.

  Further, the material of the original is not particularly limited, such as a paper medium, an OHP sheet, and a cardboard paper.

3 Registration Roller 10 Tray Size First Detection Sensor 11 Tray Size Second Detection Sensor 12 Post-Separation Sensor 17 Document Width Detection Sensor 18 Guide Restriction Plate 20 Reverse Path 30 Document Tray 100 Automatic Document Feeder (ADF)

Claims (5)

A stacking unit for stacking documents, a transport unit for transporting documents stacked on the stacking unit one by one so as to pass through a reading position, and a reading for reading an image of a document transported by the transporting unit at the reading position And a return transport path for returning the document transported by the transport means after passing through the reading position to a position upstream of the reading position, and the transport means before the document reaches the reading position. In the document reading device in which the length of the document in the transport direction is not fixed,
A first document length detection unit that is disposed on the stacking unit and detects a document length that is a length in a transport direction of the document stacked on the stacking unit;
Width detecting means for detecting a document width which is a length in a width direction orthogonal to the transport direction of the document;
In the case where a stack of originals in which a plurality of originals having different sizes are mixed is stacked on the stacking unit, based on the original width detected by the width detecting unit and the original length detected by the first original length detecting unit. A provisional size determining means for determining a maximum document size among a plurality of predicted document sizes as a provisional document size;
Second document length detection means for detecting the document length by measuring the length of the document being conveyed by the conveyance means in the conveyance direction;
An actual size determining unit that determines an actual document size based on the document width detected by the width detection unit and the document length detected by the second document length detection unit;
When the provisional document size determined by the provisional size determination unit is equal to the actual document size determined by the actual size determination unit, the reading unit performs reading of the image according to the provisional document size. On the other hand, if the provisional document size and the actual document size are different, the document is returned to the upstream position via the return conveyance path by the conveyance unit, and according to the actual document size. A document reading apparatus comprising: control means for causing the reading means to read the original image again.   The width detection unit includes a first detection unit that detects a position of a regulating member that regulates both ends in the width direction of the bundle of documents stacked on the stacking unit, and a document that is transported from the stacking unit by the transport unit. A second detection unit that detects the position of one end in the width direction, and the document width based on the position detected by the first detection unit and the position detected by the second detection unit; The document reading apparatus according to claim 1, wherein:   When the temporary document size determined by the temporary size determination unit is different from the actual document size determined by the actual size determination unit, the control unit reads the image according to the actual document size. 2. The document reading apparatus according to claim 1, wherein the presence or absence of the next document is not confirmed until the redoing is completed. A stacking unit for stacking documents, a transport unit for transporting the documents stacked on the stacking unit one by one so as to pass through the reading position of the reading device, and the transporting unit transported the document past the reading position. An automatic document feeder that includes a return conveyance path for returning the document to a position upstream of the reading position, and in which the length of the document in the conveyance direction by the conveying means is not determined before the document reaches the reading position. ,
A first document length detection unit that is disposed on the stacking unit and detects a document length that is a length in a transport direction of the document stacked on the stacking unit;
Width detecting means for detecting a document width which is a length in a width direction orthogonal to the transport direction of the document;
When a plurality of originals having different sizes are stacked on the stacking unit, the document is predicted based on the document width detected by the width detecting unit and the document length detected by the first document length detecting unit. A temporary size determining means for determining a maximum standard size among a plurality of standard sizes as a temporary document size;
Second document length detection means for detecting the document length by measuring the length of the document being conveyed by the conveyance means in the conveyance direction;
An actual size determining unit that determines an actual document size based on the document width detected by the width detection unit and the document length detected by the second document length detection unit;
When the provisional document size determined by the provisional size determination unit is equal to the actual document size determined by the actual size determination unit, the reading of the image by the reading device performed according to the provisional document size is performed. On the other hand, if the provisional document size and the actual document size are different, the document is returned to the upstream position via the return conveyance path by the conveyance unit, and according to the actual document size. An automatic document feeder comprising: control means for causing the reading device to read the original image again. A stacking unit for stacking documents, a transport unit for transporting the documents stacked on the stacking unit one by one so as to pass through the reading position, and a reading for reading an image of the document transported by the transporting unit at the reading position And a return transport path for returning the document transported by the transport means after passing through the reading position to a position upstream of the reading position, and the transport means before the document reaches the reading position. In the control method of the document reading device in which the length of the document in the transport direction is not fixed,
A first document length detecting step of detecting a document length which is a length in a transport direction of the document stacked on the stacking means by a first document length detecting unit disposed on the stacking unit;
A width detecting step of detecting a document width which is a length in a width direction orthogonal to the transport direction of the document;
When a plurality of originals having different sizes are mixedly stacked on the stacking unit, it is predicted based on the original width detected in the width detection step and the original length detected in the first original length detection step. A temporary size determining step for determining a maximum standard size among a plurality of standard sizes as a temporary document size;
A second document length detection step of detecting the document length by measuring the length of the document being conveyed by the conveying means in the conveyance direction;
An actual size determination step for determining an actual document size based on the document width detected in the width detection step and the document length detected in the second document length detection step;
When the provisional document size determined in the provisional size determination step is equal to the actual document size determined in the actual size determination step, reading of the image by the reading unit is performed according to the provisional document size. On the other hand, if the provisional document size and the actual document size are different, the document is returned to the upstream position via the return conveyance path by the conveyance unit, and according to the actual document size. And a control step of causing the reading unit to read the original image again.