JP2007243441A - Image reader, its control method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader which can read out the entire region of an image surely without reducing the productivity of reading out a document, and to provide its control method and program. <P>SOLUTION: On a document carrying path, a transmission light sensor 18 is provided for detecting the tip position and the right/left end positions of an oblique document, read-out size of the document by a scanner unit 209 is detected with reference to each point before reading of document is started, and corresponding memory area of a page memory 406 is assured when reading operation is performed. With such an arrangement, entire region of the document can be read out surely without losing peformance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image reading apparatus, a control method for the apparatus, and a control program.

  Conventionally, an image reading unit having a function of reading a document while conveying the document at a constant speed from an automatic document feeder (ADF) while the document reading unit is fixed at a predetermined reading position and is kept as it is, is called an image reading function. The device is known.

  In an image reading apparatus capable of continuous scanning, there is a problem in that a document to be conveyed is conveyed obliquely, so-called skewing occurs, and the read image is inclined. In view of this, a technique has been proposed in which skew of a document is detected by detecting a side shift of the document (see Patent Document 1).

Further, a technique is proposed in which the background is black, and each vertex (outer edge) of the document is detected by the first scanning of the document and an image is read by the second scanning of the document. .
JP-A-6-92512

  However, in the technique of the above-mentioned patent document 1, the skew amount is determined based on the amount of deviation of the side of the document. However, since the leading edge of the document cannot be taken into account, the read image causes the leading edge to be lost and the paper document is faithfully reproduced. There is a possibility that electronic data cannot be changed.

  Further, the technique of detecting the outer edge of the document by scanning twice described above has a problem that the productivity of reading the document is lowered, which causes inconvenience to the user when handling a large amount of documents.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading apparatus capable of reliably reading the entire image area without deteriorating document reading productivity, a control method for the apparatus, and a control program.

  In order to achieve the above object, an image reading apparatus according to a first aspect of the present invention includes an original conveying unit that conveys an original, an image reading unit that reads an image, and an original reading position of the image reading unit with respect to the original conveying direction. An upstream edge detection unit that detects an outer edge portion of the document while conveying the document by the document conveying unit, and detects a position corresponding to a vertex of the outer edge portion of the document detected by the outer edge detection unit. A vertex detection unit; and a size determination unit that determines an image size to be read by the image reading unit based on a vertex detected by the vertex detection unit before the image reading unit starts reading the document. It is characterized by.

  According to a sixth aspect of the present invention, there is provided a control method for an image reading apparatus, wherein a document conveying unit that conveys a document, an image reading unit that reads an image, and an upstream of a document reading position of the image reading unit with respect to a document conveying direction. A method for controlling an image reading apparatus including a sensor, wherein an outer edge detecting step of detecting an outer edge portion of the original document by the sensor while the original is conveyed by the original conveying means, and a detection of the original detected by the outer edge detection step. A vertex detection step for detecting a position corresponding to the vertex of the outer edge portion, and reading by the image reading unit based on the vertex detected by the vertex detection step before the image reading unit starts reading the document. And a size determining step for determining an image size.

  According to a seventh aspect of the present invention, there is provided a control program including a document conveying unit that conveys a document, an image reading unit that reads an image, and a sensor that is installed upstream of the document reading position of the image reading unit with respect to the document conveying direction. A control program executed by the image reading apparatus, wherein an outer edge detection module that detects an outer edge portion of the original with the sensor while the original is conveyed by the original conveying means, and an outer edge of the original detected by the outer edge detection module A vertex detection module for detecting a position corresponding to the vertex of the image reading unit, and an image read by the image reading unit based on the vertex detected by the vertex detection module before the image reading unit starts reading the document. And a size determining module for determining a size.

  According to the present invention, since the image size to be read by the image reading unit is determined based on the vertex detected by the vertex detecting unit before the reading of the document by the image reading unit is started, the reading productivity of the document is improved. The entire image area can be reliably read without being lowered. Further, since the image data storage area corresponding to the image size is secured before the image reading unit starts reading the original, it is possible to avoid wasteful use of the image memory.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an image reading apparatus according to an embodiment of the present invention.

  The image reading apparatus shown in FIG. 1 includes a document conveying device (ADF) 100, a reader unit 200, and an external control device 400 that is a storage location for the read image.

  First, in FIG. 1, the ADF 100 is fed from the uppermost document to the separating unit 2 by the pickup roller 1 from the document bundle S set on the document tray 20 with the surface facing upward. The separation unit 2 is provided with a separation roller on the upper side and a separation pad on the lower side, and performs separation one by one from the uppermost sheet of the document bundle S.

  When reading the image on the front side with a single-sided document, the separated document is subjected to skew correction during separation and conveyance by the first registration roller 3, and then from the first registration roller 3 to the second registration roller 4 and the second registration roller 4. It is conveyed to one conveyance roller 5. Then, the surface image is read while the reading position R is being conveyed. When the trailing edge of the document passes the reading position R, the solenoid 22 is pressurized and the document is nipped, and the document is placed on the sheet discharge tray 21 via the second conveyance roller 6 and the sheet discharge roller 8. It is discharged in turn.

  When reading both front and back images with a double-sided document, the separated document is subjected to skew correction during separation and conveyance by the first registration roller 3 and then from the second registration roller 4 to the first conveyance roller 5. And conveyed to the second conveying roller 6. Then, the surface image is read while the reading position R is being conveyed. When the document passes the reading position R, the solenoid 22 is pressurized and the document is nipped. Then, the document is once transported in the direction of the paper discharge tray 21 by the second transport roller 6 and the paper discharge roller 8. When the trailing edge of the document passes through the paper discharge sensor 13 and OFF of the paper discharge sensor 13 is detected, the conveyance of the document is temporarily stopped with the trailing edge of the document nipped by the paper discharge roller 8.

  After that, the document is switched back and conveyed, and the skew correction is performed again by the second registration roller 4. Thereafter, the solenoid 22 is released, and the document is conveyed by the second registration roller 4, the first conveyance roller 5, and the second conveyance roller 6. While the original passes through the reading position R, the image on the back side is read.

  If the document is discharged on the discharge tray 21 with the second transport roller 6 and the discharge roller 8 as it is, the order of the surfaces set on the document tray 20 is different.

  Therefore, the document whose back side has been read is conveyed again toward the sheet discharge tray 21 by the second conveyance roller 6 and the sheet discharge roller 8. When the trailing edge of the document passes through the paper discharge sensor 13 and OFF of the paper discharge sensor 13 is detected, the conveyance of the document is temporarily stopped with the trailing edge of the document nipped by the paper discharge roller 8. Thereafter, the document is switched back and conveyed to the second registration roller 4, the first conveyance roller 5, and the second conveyance roller 6, and then the sheet is discharged onto the sheet discharge tray 21 by the sheet discharge roller 8. It is discharged in order. However, even while the reading position R is being conveyed, the document image is not read during this period. Further, the transmitted light sensor 18 detects the conveyance state of the document.

  The reader unit 200 optically reads image information recorded on a document, photoelectrically converts it, and inputs it as image data. The reader unit 200 includes an ADF platen 201, a book platen 202, a scanner unit 209 having a lamp 203 and a mirror 204, mirrors 205 and 206, a lens 207, and a CCD sensor 208.

  When reading a document image conveyed from the ADF 100, the reader unit 200 moves the scanner unit 209 below the ADF platen 201 and stops the image information while the document is conveyed on the reading position R. read.

  Further, when reading an image of a document placed on the book platen 202, the scanner unit 209 is moved in a sub-scanning direction from a document set reference position (not shown) to read image information.

  In reading the image information, the lamp 203 is turned on and the original is irradiated. The reflected light of the document is input to the CCD sensor 208 via the mirrors 204, 205, 206 and the lens 207. Then, the reflected light of the original input to the CCD sensor 208 is subjected to an electrical process such as photoelectric conversion, and is subjected to a normal digital process.

  FIG. 2 is an explanatory diagram of the drive system of the ADF 100 in FIG.

  The separation unit 2 and the first registration roller 3 are driven by a separation motor M1. The second registration roller 4, the first transport roller 5, and the second transport roller 6 are driven by a paper feed motor M2. The paper discharge roller 8 is driven by a paper discharge motor M3.

  In the present invention, the ADF 100 and the reader unit 200 may be integrated.

  FIG. 3 is a diagram showing the configuration of the transmitted light sensor 18 of FIG. The transmitted light sensor 18 includes an LED 16 and a light receiving sensor 17 that are arranged in a direction orthogonal to the document conveying direction indicated by the arrow in FIG. When the document passes between the LED 16 and the light receiving sensor 17, the level of the light receiving sensor 17 is lowered, and the arrival of the document can be detected.

  FIG. 4 is a block diagram showing a control configuration of ADF 100.

  The ADF 100 includes a CPU 800 as control means, a read only memory (ROM) 801, a random access memory (RAM) 802, an output port 803, and an input port 804. The CPU 800 is connected to the ROM 801, RAM 802, output port 803, and input port 804.

  The ROM 801 stores a control program, and the RAM 802 stores input data and work data. The output port 803 is connected to a separation motor M1, a paper feed motor M2, a paper discharge motor M3, a separation solenoid SL, and a paper feed clutch CL. To the input port 804, a post-separation sensor 10, a registration sensor 11, a read sensor 12, a paper discharge sensor 13, a document detection sensor 14, a document length detection sensor 15, and a document width detection sensor 810 are connected.

  The CPU 800 controls the separation motor M1, the paper feed motor M2, the paper discharge motor M3, the separation solenoid SL, and the paper feed clutch CL in accordance with a control program stored in the ROM 801. The CPU 800 performs serial communication with a CPU (not shown) of the reader unit 200 and exchanges control data with the reader unit 200.

  FIG. 5 is a block diagram illustrating a control configuration of the reader unit 200.

  In FIG. 5, reference numeral 256 denotes a CPU unit that controls all of the reader unit 200. The CPU unit 256 includes a program storage ROM (not shown), a work RAM, and the like.

  A motor driver unit 257 is a driver circuit for driving the optical system driving motor. Reference numeral 258 denotes a sensor signal input unit for taking signals from various sensors of the reader unit 200 into the CPU unit 256. The CPU unit 256 controls the reader unit 200 using the motor driver unit 257 and the sensor signal input unit 258. A paper gap correction processing unit 254 performs paper gap correction. Reference numeral 253 denotes an image memory. An image signal imaged on the CCD 208 by the lens 207 is converted into digital image data, and various image processes are performed by the image processing unit 252 and written in the image memory unit 253. Data written in the image memory unit 253 is sequentially transmitted to the external controller device 400 through the interface 260. Input from the transmitted light sensor 18 is input to the CPU unit 256, and control of document size detection described later is performed.

  FIG. 6 is a block diagram showing a control configuration of the external controller device 400.

  The external controller device 400 is connected to the reader unit 200 via the reader interface 401. The external controller device 400 includes a reader interface 401, a memory controller 402, an encoder 403, a page memory 406, a CPU 407, a storage device (hard disk) 408, and an operation unit 412.

  The image is transmitted from the image memory unit 253 of the reader unit 200 to the external controller device 400 line by line via the controller interface 260 and the reader interface 401. Separately, a control command for reading is transmitted and received between the controller device 400 and the reader unit 200 by serial communication via the controller interface 260 and the reader interface 401, and a reading operation is performed.

  One of the control commands at this time includes document size information detected by the reader unit 200, and when the external controller device 400 receives this size information, the memory controller 402 sets a memory area for storing the document. The page memory 406 is secured. Then, the image data before compression of the transmitted image is sequentially stored in a page memory 406 secured in advance. The encoder 403 converts the image data in the page memory 406 into a specific image format (JPEG, TIFF, etc.). The converted image data is stored in the storage device 408 as an image file.

  The storage device 408 stores a control program for the external controller device 400. The CPU 407 controls each unit of the external controller device 400 according to the control program. The operation unit 412 instructs the reader unit 200 on a reading job mode (single-sided or double-sided), a full-face reading mode, or the like. The external controller device 400 performs an image reading operation by communicating with the reader unit 200 in accordance with the job mode instructed by the operation unit 412.

  In the present embodiment, the external controller device 400 is connected to the reader unit 200 via the reader interface 401. However, each component of the external controller device 400 may be built in the reader unit 200. .

  Next, the image reading apparatus can designate a normal mode for performing normal size detection and an e-document mode for performing size detection for reading the entire area.

  FIG. 7 is a diagram illustrating a display example of the operation unit when the normal mode is selected, and FIG. 8 is a diagram illustrating a display example of the operation unit when the e document mode is selected. Both are screens displayed on the operation unit 412 of the external controller device 400.

  In the normal mode of FIG. 7, the e document mode button 701 at the top of the screen is pressed to select the e document mode. When the e document mode button 701 is pressed, the screen of the operation unit 412 is switched to a display as shown in FIG. In the e-document mode, since the read original is saved as a file, the location and file name for saving the document file are entered in the document name box 801. When a document reading operation is performed in this state, size detection for reading the entire area is performed. Further, when switching to the normal mode, it is switched by pressing any of the copy button 802, SEND button 803, or BOX button 804 at the top of the screen in FIG. As an example, when the copy button 802 is pressed, the display is switched to the display of FIG.

  Next, a size detection method for reading the entire area of the skewed document will be described. This size detection is performed in common in the normal mode and the e-document mode.

  First, a method for detecting the outer edge position of the document by the transmitted light sensor 18 will be described.

  When the original passes through the transmitted light sensor 18 as shown in FIG. 9, the output value of the light receiving sensor 17 changes as shown in FIG. If it falls below the paper presence level, it is determined that there is paper. A position X in FIG. 10 shows the case where the leading edge of the document in FIG. 9 has passed the light receiving sensor 17, and the position of each vertex of the document is stored in the CPU unit 256.

  Next, a method for determining the image size will be described. In order to read the entire area of the skewed document, the image size including the skew is determined as shown in FIG.

  First, as shown in FIG. 12, when the leading edge of the document reaches the transmitted light sensor 18, the position where the level of the light receiving sensor 17 has changed is stored in the CPU 256. The end portion of the transmitted light sensor 18 is set to zero, and the tip position is stored as P1 in the CPU unit 256, and the time T1 at this time is also stored in the CPU unit 256.

  Next, after the leading edge of the document is detected, the edge positions Y1 and Y2 at which the level of the light receiving sensor 17 changes are monitored as shown in FIGS. The edge position Y1 is on the side close to the 0 point, and the edge position Y2 is on the side far from the 0 point. Then, the point where the edge position Y1 has increased from the decrease or the edge position Y2 has shifted from the increase to the decrease is recognized as the main scanning end, the position where the edge position Y1 has increased from the decrease is P2, the time at that time is T2, the edge The position where the position Y2 has decreased from the increase is stored in the CPU 256 as P3, and the time at that time is T3. FIG. 14 shows the original state when the position P2 (main scanning end) is detected, and FIG. 15 shows the original state when the position P3 (main scanning end) is detected. Then, as shown in FIG. 16, the rear end of the document passes through the transmitted light sensor 18, and the position at which the level of the light receiving sensor 17 last changed from the presence of paper to the absence of paper is stored in the CPU 256 as the rear end position P4. The time T4 at this time is also stored in the CPU unit 256.

  The document size including skew is determined as follows.

  First, since the document size for sub-scanning cannot be determined unless the trailing edge position P4 of the document is detected, the trailing edge position P4 of the document is detected when the leading edge of the document reaches the lead sensor 12. Whether or not the CPU unit 256 switches the size detection method.

  When the rear end position P4 of the document can be detected, the main scanning size X = P3-P2, and the sub-scanning size Y is determined by the CPU unit 256 assuming that the conveying speed of the separation motor M1 is V. Is obtained from the sub-scanning size Y = (T4−T1) · V.

If the trailing edge position P4 of the document cannot be detected, the CPU unit 256 performs processing for predicting the document size. The CPU unit 256 determines how much the document has been rotated based on the leading end position P1 and the position (for example, P3) detected first among the main scanning end positions P2 and P3. That is, the skew angle θ is obtained as shown in FIG. This is calculated as θ = tan ⁻¹ ((T3−T1) · V) / (P3−P1)) where V is the conveyance speed of the separation motor M1. The short side a of the document is a = ((T3−T1) · V) ² + (P3−P1) ² ) ^1/2 . The fixed size is obtained from a and the long side b of the fixed size is obtained. For example, when a is calculated to be about 297 mm, the standard size is obtained as A3, and the length of b is set to 420 mm. Then, the CPU unit 256 obtains a final document size based on b and the skew angle θ. In FIG. 17, since K is K = b · cos θ and L is L = b · sin θ, the final document size is the main scanning size X = (P3−P1) + L, and the sub scanning size Y = ((T3− T1) · V) + K. Then, the detected document size is transmitted to the external controller device 400 by the size notification method described below.

  Next, a size notification method, a memory securing method of the external control device 400, and an image data storage method will be described.

  In the normal mode, the CPU 256 transmits information on the size of the standard paper (A4, A3, etc.) approximate to these sizes to the external control device 400 together with the detected main scanning size and sub-scanning size information. This is because it is assumed that the read image of the document is copied on paper.

  On the other hand, since the e document mode is assumed to be stored in an image file, it is not necessary to transmit to the external control device 400 information on the standard paper size that approximates the detected main scanning size and sub-scanning size.

  Therefore, in the e document mode, the CPU unit 256 transmits information on the detected main scanning size and sub-scanning size to the external control device 400. In both modes, the CPU 256 externally controls the main scanning size and sub-scanning size information and / or the standard paper size information when the leading edge of the document turns on the read sensor 12 before the first conveying roller 5. To device 400.

  In the external control device 400, the page memory 406 is secured by the memory controller 402 in accordance with the received size information (main scanning size and sub-scanning size information). Specifically, since the image data is transmitted as data of 8 bits per pixel, the number of main scanning pixels × the number of sub scanning pixels × 8 bits for a monochrome document, the number of main scanning pixels × the number of sub scanning pixels × for a color document. A memory capacity corresponding to 8 bits × 3 is secured.

  In the external controller device 400, image data transmitted from the image memory 253 of the reader unit 200 via the interface 260 and the reader interface 401 are sequentially stored in the secured memory. After the storage of the image data for one page is completed, the encoder 403 performs image formatting and stores it in the storage device 408.

  As described above, according to the present embodiment, the transmitted light sensor 18 for detecting the leading edge position and the left and right end positions of the skewed document is provided in the document transport path, and the scanner unit 209 is based on each point. Since the reading size of the original is detected before the reading of the original is started and the memory area of the page memory 406 is secured and the reading operation is performed, the entire area of the original can be read reliably without degrading the performance. it can. Furthermore, since the original is read in consideration of the skew of the original, the memory area of the page memory 406 can be used effectively.

  Another object of the present invention is to supply a storage medium storing software program codes for realizing the functions of the above-described embodiments to a system or apparatus, and the computer of the system or apparatus (or CPU, MPU, or the like). Is also achieved by reading and executing the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention. .

  Examples of the storage medium for supplying the program code include a floppy (registered trademark) disk, a hard disk, a magneto-optical disk, a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, and a DVD. An optical disc such as RW or DVD + RW, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used. Alternatively, the program code may be downloaded via a network.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (Operating System) running on the computer based on the instruction of the program code Includes a case where the functions of the above-described embodiments are realized by performing part or all of the actual processing.

  Furthermore, after the program code read from the storage medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the expanded function is based on the instruction of the program code. This includes a case where a CPU or the like provided on the expansion board or the expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

1 is a diagram illustrating a configuration of an image reading apparatus according to an embodiment of the present invention. It is explanatory drawing of the drive system of ADF of FIG. It is the figure which showed the structure of the transmitted light sensor of FIG. It is a block diagram which shows the control structure of ADF. It is a block diagram which shows the control structure of a reader part. It is a block diagram which shows the control structure of an external controller apparatus. It is a figure which shows the example of a display of the operation part when the normal mode is selected. It is a figure which shows the example of a display of the operation part when e document mode is selected. It is explanatory drawing which shows that the original document passed the transmitted light sensor. FIG. 10 is a diagram illustrating an output state of the light receiving sensor when the document in FIG. 9 passes the transmitted light sensor. FIG. 6 is a diagram showing a document size area in e-document mode (all area reading mode). FIG. 6 is a diagram illustrating a state when the leading edge of a document being conveyed reaches a transmitted light sensor. (A) is a figure which shows the state in which the conveyed document passes a transmitted light sensor, (B) demonstrates the change of the light reception level of the light receiving sensor when the conveyed document passes a transmitted light sensor. FIG. FIG. 6 is a diagram illustrating a state when a main scanning end at the rear end of a conveyed document reaches a transmitted light sensor. FIG. 6 is a diagram illustrating a state when a main scanning end portion at the front end of a conveyed document reaches a transmitted light sensor. FIG. 6 is a diagram illustrating a state when a main scanning end at the rear end of a conveyed document reaches a transmitted light sensor. FIG. 5 is a diagram illustrating a method for determining the size of a skewed document.

Explanation of symbols

18 Transmitted Light Sensor 100 Document Feeder (ADF)
200 Reader unit 201 ADF platen 202 Book platen 203 Lamp 204 Mirror 209 Scanner unit 400 External control device 401 Reader interface 402 Memory controller 403 Encoder 406 Page memory 407 CPU
408 Storage device (hard disk)
412 Operation unit

Claims (7)

An original conveying means for conveying an original;
Image reading means for reading an image;
An outer edge detection unit that is installed upstream of the document reading position of the image reading unit with respect to the document conveying direction and detects an outer edge portion of the document while conveying the document by the document conveying unit;
Vertex detection means for detecting a position corresponding to the vertex of the outer edge portion of the document detected by the outer edge detection means;
An image determining unit configured to determine an image size to be read by the image reading unit based on a vertex detected by the vertex detecting unit before the image reading unit starts reading an original; Reader.   An accumulating unit for accumulating image data of a document read by the image reading unit, and the accumulating unit according to an image size determined by the size determining unit before the reading of the original by the image reading unit is started. The image reading apparatus according to claim 1, further comprising storage area securing means for securing the storage area.   The outer edge detection unit includes a light emitting member and a light receiving member that are uniformly arranged in the longitudinal axis direction, and is shielded in the longitudinal axis direction when a document passes between the light emitting member and the light receiving member. 3. The image reading apparatus according to claim 1, wherein the position and time are detected.   A selection unit configured to select a normal reading mode and an oblique full surface reading mode, and when the oblique entire surface reading mode is selected by the selection unit, the size determining unit determines an image size read by the image reading unit; The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus.   When the leading edge of the original reaches a predetermined position, the image size determining method by the size determining means is changed according to whether or not the vertex detecting means detects the vertex of the trailing edge of the original. The image reading apparatus according to claim 1, wherein: A control method for an image reading apparatus, comprising: an original conveying unit that conveys an original; an image reading unit that reads an image; and a sensor that is installed upstream of the original reading position of the image reading unit with respect to the original conveying direction. And
An outer edge detecting step of detecting an outer edge portion of the original by the sensor while the original is conveyed by the original conveying means;
A vertex detection step for detecting a position corresponding to the vertex of the outer edge portion of the document detected by the outer edge detection step;
A size determining step of determining an image size to be read by the image reading unit based on the vertex detected by the vertex detecting step before starting reading of the original by the image reading unit; A method for controlling a reader. Control executed by an image reading apparatus including an original conveying unit that conveys an original, an image reading unit that reads an image, and a sensor that is installed upstream of the original reading position of the image reading unit with respect to the original conveying direction. A program,
An outer edge detection module for detecting an outer edge portion of the document by the sensor while the document is conveyed by the document conveying means;
A vertex detection module for detecting a position corresponding to the vertex of the outer edge portion of the document detected by the outer edge detection module;
A control unit comprising: a size determination module that determines an image size read by the image reading unit based on a vertex detected by the vertex detection module before the image reading unit starts reading a document; program.

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