JP2008042841A - Document reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive document reading apparatus capable of obtaining a normal image even in a case where a document is slipped by a paper type or deterioration with the passage of time. <P>SOLUTION: In the document reading apparatus which reads a document with a plurality of punched holes while feeding the document and processes read image data, positions of the punched holes are detected from the read image data, and slippage of document feeding during document reading is detected based on a positional relationship of the punched holes, thereby discriminating whether the relevant document is to be scanned again. Otherwise, the extension of an image in the area where the slippage of document feeding occurs, is specified and an extending portion of the image is reduced just for the amount of the slippage of document feeding detected before. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a document processing apparatus used in an image scanner, a facsimile machine, a copying machine, and the like, and more particularly to a document processing apparatus that reads a document while being conveyed and processes the read image data.

2. Description of the Related Art Conventionally, in a document movement type document processing apparatus that reads a document while being conveyed, the document is conveyed by a conveyance roller, and the document is read by a scanner unit. However, such a document processing apparatus has a problem that the document is liable to slip due to the type and state of the paper or the deterioration of the parts of the reading device over time. Some papers are caused by a decrease in friction due to paper dust and the like, and parts are subject to mechanical manufacturing variations and accuracy variations during production. Even if there is no problem with the performance in the initial state, the document slips due to the decrease in friction due to paper dust and the like, and the deterioration of parts over time. It may be possible. In order to solve such a problem, in the prior art disclosed in Japanese Patent Laid-Open No. 7-297999, a document having a predetermined length is conveyed in advance, and the number of motor pulses generated in synchronization with document movement is reduced. The number of pulses is detected in the same manner when actually reading, and correction is performed by comparing the two pulse numbers. In the prior art disclosed in Japanese Patent Laid-Open No. 2002-232656, the document moving speed being read is detected and stored in association with the position on the document, and image processing corresponding to the detected speed is performed. Correction is performed at the original position.
JP 7-297999 A JP 2002-232656 A

  However, in the method disclosed in Japanese Patent Laid-Open No. 7-297999, since the entire original document is uniformly reduced, the local image expansion itself at the portion where the slip has occurred cannot be eliminated. There are various problems such as the need to pass through several types. Further, in the method of Japanese Patent Laid-Open No. 2002-232656, in order to detect the document moving speed, it is necessary to add a driven roller that rotates following the document movement, and hardware such as an encoder attached thereto. There is a problem that the manufacturing cost of the apparatus increases.

  Therefore, the present invention pays attention to the fact that a document slip occurs in a document processing device such as a document reading device or a document transport device, and normal even if the document slips due to paper type / state or deterioration over time. An object of the present invention is to provide a document processing apparatus capable of obtaining a clear image.

  By the way, when storing a cut document, JIS Z 8303 (multi-hole-B5 vertical 26 holes, A4 vertical 30 holes) and FBA (File & Binder Association Japan: 6 holes, 4 holes, 3 holes) standards. In general, it is often performed that a sheet is punched and bound using a file binder according to each standard.

  In order to solve the above-described problems, in the invention of claim 1, a document reading apparatus that reads and conveys a document having a plurality of punch holes perforated according to such a standard and processes the read image data is read. Punch hole detection processing means for detecting the position of a punch hole from the obtained image data, and slip detection means for determining the presence / absence of a slip during document conveyance from the punch hole position information obtained by the punch hole detection processing means And with.

  Further, in the invention of claim 2, in the invention of claim 1, the slip detection means includes not only the presence / absence of the slip at the time of transporting the document but also the amount of the slip at the time of transport of the document and The area is determined.

  According to a third aspect of the present invention, a punch hole detection process for detecting a position of a punch hole from the read image data in a document reading apparatus that reads and conveys a document having a plurality of punch holes and processes the read image data. By comparing the standard punch hole pattern, the standard punch hole pattern, the punch hole position information obtained by the punch hole detection processing means, and the standard punch hole pattern. The apparatus includes a slip detection unit that determines whether or not there is a slip during document transportation, a slip amount during document transportation, and an area in the document where the slip occurs during document transportation.

  According to the invention of claim 4, in the invention of claim 3, the standard punch hole pattern has an original size, presence / absence of symmetry with respect to the center of the punch hole row, distance of the punch hole row from the document edge, distance between the punch holes. The configuration described in the above.

  According to the invention of claim 5, in the invention of claim 3, when a slip is detected by the slip detection means, an inquiry means for inquiring whether or not the document needs to be rescanned is provided.

  According to a sixth aspect of the present invention, in the third aspect of the present invention, a slip occurrence page recording means for recording a page in which slip is detected when reading a plurality of pages of a document, and whether or not the entire document needs to be rescanned. An inquiry means for making an inquiry is provided.

  According to a seventh aspect of the present invention, in the third aspect of the present invention, an image spread detecting means for detecting an image spread occurrence portion of the document caused by the slip from an area in the document in which the slip has occurred during the document transport, The apparatus includes a stretch deletion unit that deletes the extended portion of the image detected by the image spread detection unit from the read image data by the amount of slip during the document conveyance.

  According to an eighth aspect of the present invention, in the original reading device according to the fourth aspect of the present invention, an image spread detecting means for detecting an image spread occurrence portion of the original caused by the slip from an area in the original where the slip has occurred during the transport of the original. And an extension deletion unit that deletes the extended portion of the image detected by the image extension detection unit from the read image data by the amount of slip during the document conveyance.

  According to the present invention, in the first aspect of the present invention, in a document reading apparatus that reads and conveys a document having a plurality of punch holes and processes the read image data, the position of the punch holes is detected from the read image data. Additional hardware is added by providing punch hole detection processing means and slip detection means for determining the presence / absence of slippage during document conveyance based on the punch hole position information obtained by the punch hole detection processing means. In addition, the presence or absence of slippage during document conveyance can be reliably realized at low cost.

  According to the second aspect of the present invention, it is possible to determine the amount of slip when the document is conveyed and the area in the document where the slip occurs when the document is conveyed.

  According to a third aspect of the present invention, a punch hole detection process for detecting a position of a punch hole from the read image data in a document reading apparatus that reads and conveys a document having a plurality of punch holes and processes the read image data. By comparing the standard punch hole pattern, the standard punch hole pattern, the punch hole position information obtained by the punch hole detection processing means, and the standard punch hole pattern. The standard punch has a configuration that includes slip detection means that determines whether or not there is slippage during document transport, the amount of slip during document transport, and the area in the document where slippage has occurred during document transport. For documents with punch holes according to the hole pattern, it is possible to perform slip determination with higher accuracy.

  According to the invention of claim 4, in the invention of claim 3, the standard punch hole pattern has an original size, presence / absence of symmetry with respect to the center of the punch hole row, distance of the punch hole row from the document edge, distance between the punch holes. An example of the necessary and sufficient definition of the standard punch hole pattern is shown.

  Further, in the invention of claim 5, in the invention of claim 3, when a slip is detected by the slip detection means, an inquiry means for inquiring whether or not the document needs to be rescanned is provided. Enables reliable image reading.

  According to a sixth aspect of the present invention, in the third aspect of the present invention, a slip occurrence page recording means for recording a page in which slip is detected when reading a plurality of pages of a document, and whether or not the entire document needs to be rescanned. With the configuration including the inquiry means for making an inquiry, it is possible to easily and reliably read an image even on a multi-page document.

  According to the seventh and eighth aspects of the invention, in the third and fourth aspects of the invention, the image enlargement is detected from a region in the original where the slip has occurred during the document conveyance, and an image occurrence portion of the original caused by the slip is detected. Document conveyance by a configuration comprising: a detection unit; and an extension deletion unit that deletes the extended portion of the image detected by the image spread detection unit from the read image data by the amount of slip during the document conveyance. The spread of the image caused by sliding is easily and reliably corrected to enable reliable image reading.

(Example 1)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the present invention. In FIG. 1, an original reading apparatus 100 includes an IF control unit 101, a main control unit 102, an original conveyance control unit 103, an image reading control unit 104, an ADF 105, The image forming apparatus includes a first document conveying roller 106, a second document conveying roller 107, a gray reference roller 108, a registration sensor 109, a reading timing sensor 110, and a scanner CCD sensor 111. In the figure, a host device 118 includes an IF control unit 112, an image The processing unit 113, the image memory 114, the main control unit 115, a display device 116 such as a CRT, and an input device 117 such as a keyboard / mouse, and the document reading device 100 and the host device 118 are connected by an interface 119.

FIG. 2 is a block diagram showing a first embodiment of the present invention. A document 207 loaded on an ADF (automatic document feeder), a first document transport roller 201, a second document transport roller 202, and a known reflectance. It comprises a gray reference roller 203 (50% here), a scanner 204, a reading timing sensor 205, and a registration sensor 206. In the drawing, the distance between the scanner CCD sensor and the second document conveying roller is indicated by L ₁ (208), and the distance between the reading timing sensor and the scanner CCD sensor is indicated by L ₂ (209).

  Next, the operation of the present embodiment will be described using a flowchart. FIG. 3 is an overall flowchart of this embodiment. For the conveyed document, first, image data of the entire document page is written in the image memory (FIG. 1, 114) in page scan processing step S301. Next, the punch hole position in the document image data is detected in the punch hole detection processing step S302, and compared with the standard punch hole pattern recorded in advance in the punch hole pattern determination processing step S303, the matching standard punch hole pattern is specified. Do. In the subsequent document conveyance slip determination step S304, the slip amount during document conveyance is detected based on the deviation between the matched standard punch hole pattern and the punch hole position on the image data, and it is determined that the slip has occurred for the slip amount exceeding a certain threshold. To do. If no slip occurs, the process is terminated and the obtained scanned image is used as it is. If a slip has occurred, as shown in FIG. 4, the operator is informed that a slip has been detected during scanning, and a dialog for selecting whether or not to rescan is displayed (S306). Here, even when the operator designates that rescanning is unnecessary, the processing ends and the obtained scanned image is adopted as it is. If rescan is designated, a dialog prompting the operator to set paper for rescan is displayed as shown in FIG. 5 (S307). When the operator sets paper and presses the OK button in FIG. 5, the process returns to the page scan process in S301 again.

Next, the page scan processing S301 in the flowchart of FIG. 3 will be described in more detail. FIG. 6 is a flowchart for explaining the operation of the page scan processing. First, the document conveyed by the ADF (105/207) is detected by the registration sensor (109/206) (S602), whereby the document conveyance control unit (103) performs the first conveyance roller (106/201) and the second. The rotation of the document conveying roller (107/202) and the gray reference roller (108/203) is started and the light source of the scanner is turned on to perform shading correction. When the reading timing sensor (110/205) detects the leading edge of the document (YES in S605), the document is further conveyed by the distance L ₂ (209) between the reading timing sensor and the scanner (S606), and reading for one line is performed. Is written in the image memory (114) (S608). Once the reading is started, the reading of the original is continued while the reading timing sensor is ON or the original transport amount after the OFF is less than L ₂ (209) (S609). Read timing sensor is OFF, the further finished reading the L ₂ or more document conveying is performed, turning off the scanner light source (S610). Further, a document having a length exceeding the distance L ₁ (208) between the scanner and the second document transport roller shown in FIG. 2 is transported, and the document is discharged (S611). After the document is discharged, the rotation of the first transport roller, the second document transport roller, and the gray reference roller is stopped (S612).

  Next, the punch hole detection process S302 in the flowchart of FIG. 2 will be described in detail. FIG. 7A is a schematic diagram illustrating punch holes in a white background document, and FIG. 7B is a characteristic diagram illustrating an example of image signal levels of punch holes and other portions. In this embodiment, the punch hole is assumed to be a circle having a diameter of 3 to 7 mm regardless of the standard. For the portion where the punch hole exists, the surface of the gray reference roller 203 is scanned as it is, so that the signal level inside the punch hole takes a value corresponding to the reflectance. Therefore, if the page document data has a circular portion having the same signal level as that of the gray reference roller portion and a diameter of 3 to 7 mm, it can be estimated as a punch hole.

FIG. 9 shows the punch hole positions detected by the punch hole detection process S302. 901 is a page scan image stored in the image memory 114, 902 is a document area, C1 (903) and C2 (904) are corners of the document, and a _n (a ₁ ... A _n ) (905) Are n punch hole rows detected in the document area 902.

For the page document data detecting punch holes is completed, C1, C2 and the coordinates on the paper size storage unit (not shown) in the host device 118, the center a ₁ ··· a _n of the detected punched holes, respectively The coordinates are stored in punch hole position storage means (not shown) in the host device 118.

Next, the punch hole pattern determination process S303 in the flowchart of FIG. 2 will be described in detail. In this embodiment, it is assumed that the punch hole pattern is described by each value shown in FIG. That is, the document size, the presence / absence of symmetry with respect to the center point of the punch hole row, the distance d (1003) from the document edge at the center of each punch hole, and the distance between the n-1th hole and the nth hole ( e _n-1 ) (1004). FIG. 11 shows a table for each document size, which is called a standard punch hole position table. (In this embodiment, it is assumed that the punch holes are arranged in a line at a fixed distance d from the end of the page.)
In this embodiment, based on the punch hole position detected in the previous punch hole position detection stage, it is determined whether or not there is a standard punch hole position table that coincides with this. First, based on the stored coordinates of the page edges C1 and C2, it is determined whether the paper size of the original matches the standard original size. Next, a distance d from the nearest page edge is calculated. When the read document is not skewed relative to the conveying direction, d = (C2 X coordinate (c2x) - X coordinate of the punch hole _{a n (a n} x), regardless of the value of n constant ) Moreover determined for each of the punched hole position interval _{e n (= a n + 1} y-a n y) of between the center of each punched hole, these d, the value of e _n registered in the standard punch hole position table of the document size Compare with each value in turn. For a table in which the punch hole positions are not symmetrical with respect to the center, in addition to this, it is necessary to compare the punch hole interval rows from the opposite direction.

  If there is a good match among the values registered in the table, this can be used as a punch hole table for the document. In the subsequent S304, when a matching table is found, the punch hole interval of the original and the punch hole interval of the standard table are sequentially compared again, and a slip occurs in the conveyance at the time of reading the original that is larger than a certain threshold. Can be determined.

  In this embodiment, the punch hole pattern is identified by comparing the hole position detected in the punch hole detection stage with a standard punch hole position table stored in advance, and the document conveyance accuracy is verified based on this. However, when the original is specified in a sprocket hole of a computer form or JIS Z 8303, the punch hole interval takes a fixed value of 12.7 mm / 9.5 mm, respectively. In the case where such a document can be specified in advance, it is evaluated whether the interval between the detected punch holes is larger than a predetermined value without going through steps S303 and S304 in FIG. As a result, it is possible to more simply determine whether or not a conveyance slip occurs when reading a document.

In the present embodiment, a dialog as shown in FIG. 4 is used. As shown in FIG. 12, the scanned page image is displayed in a reduced size so that the operator can visually recognize whether or not slippage has actually occurred. Thus, the necessity of rescanning may be determined. Furthermore, in S304, it can be determined in which area of the document the actual slip has occurred. Therefore, the portion of the preview image shown in FIG. It is also possible to support this determination. (Fig. 13)
(Example 2)
In the first embodiment, it is determined whether or not a conveyance slip has occurred for one document, and the operator selects whether or not rescanning is necessary. In this embodiment, however, a plurality of sheets continuously fed by ADF are used. For each of the originals, after each page is scanned, it is determined whether or not there is any slippage during document conveyance, the page where the slip is detected is recorded, and these pages are scanned again. )
Next, another embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a second embodiment of the present invention, and FIG. 3 is a block diagram thereof, which is common with the first embodiment. Next, the operation of the present invention will be described with reference to a flowchart. FIG. 14 is an overall flowchart of this embodiment. First, in S1402, it is determined whether or not the document conveyed in S1401 is a document requiring scanning. The first page is always scanned, and at the time of re-scanning, the slip generation page recording table (not shown) is referred to scan only for pages where slip has been detected before. The process proceeds to S1409. In the page scan processing stage S1404, the image data of the entire original page is written into the image memory 114. For the rescanned page, the original image data of the same page is replaced with new image data. Next, the punch hole position in the document image data is detected in the punch hole detection processing step S1405, and the standard punch hole pattern that matches is identified by comparing with the standard punch hole pattern recorded in advance in the punch hole pattern processing step S1406. In the subsequent document conveyance slip determination stage 1407, the slip amount during document conveyance is detected based on the deviation between the standard punch hole pattern matched with the punch hole position on the image data, and it is determined that the slip has occurred for the slip amount exceeding a certain threshold. To do. If it is determined that a slip has occurred, the number of pages is recorded in a slip occurrence page recording table (not shown) in S1408, and the process proceeds to the next process. In step S1409, it is confirmed whether or not there are remaining pages in the document. If there are remaining pages, the process returns to S1401 to scan the next page. When scanning of all pages of the document is completed, a slip occurrence page recording table (not shown) is referred to in S1410 to determine whether or not there is a slippage page. If there is a page that has slipped, a dialog as shown in FIG. 4 is displayed in S1411 to allow the operator to select whether or not rescanning is necessary. If the operator requires rescanning, a dialog as shown in FIG. 5 is further displayed in S 1412, and the operator sets all the discharged documents on the ADF as scanned documents 207 again. Thereafter, when the OK button in FIG. 5 is clicked, control returns to S1401 again. In this embodiment, it is assumed that the scanned document is discharged in the order of pages set in advance. If there is no slip in the document in S1410, or if the operator does not specify rescan in S1411, scanning of all pages is completed in S1413. The page scan process of S1404 is equivalent to the process of S301 in FIG. 3 of the first embodiment. Similarly, the punch hole detection process of S1405, the punch hole detection process of S1405, and the punch hole pattern determination process of S1406 are S302, S303, and S304, respectively. Therefore, detailed description of the processing is omitted.

(Example 3)
In both the first and second embodiments, a document that has been determined to have slipped has been scanned again to obtain a higher-quality scanned image. However, in the third embodiment of the present invention, Using the fact that the part where the slip occurred can be specified, and further, this part of the scanned image detects the part where “elongation” occurs in the document transport direction, and this elongation is obtained by the amount of slip obtained earlier. The image distortion caused by the slip is automatically corrected by truncating the image. Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a third embodiment of the present invention, and FIG. 3 is a block diagram thereof, which is common with the first embodiment. Next, the operation of the present invention will be described with reference to a flowchart. FIG. 15 is an overall flowchart of this embodiment. Here, a single page will be described focusing on differences from the first embodiment.

  For the conveyed document, first, image data of the entire document page is written in the image memory 114 in the page scan processing stage S1501. Next, the punch hole position in the document image data is detected in the punch hole detection processing step S1502, and compared with the standard punch hole pattern recorded in advance in the punch hole pattern determination processing step S1503, the matching standard punch hole pattern is specified. Do. In the subsequent document conveyance slip determination step S1504, the slip amount during document conveyance is detected based on the deviation between the matching standard punch hole pattern and the punch hole position on the image data, and it is determined that the slip has occurred for the slip amount exceeding a certain threshold. To do. If no slip occurs, the process is terminated and the obtained scanned image is used as it is. If a slip occurs, the automatic correction processing stage of S1506 searches the “image” of the image of the document image data in the area where the slip was detected during document transport, and this portion is detected by the detected slip amount. By deleting, the slip of the scanned image due to the document conveyance is corrected (FIG. 8).

  INDUSTRIAL APPLICABILITY The present invention has applicability to a document reading device used in a copying machine, a facsimile machine, a scanner, or the like that reads a document while conveying the document and has a punch hole punched in the document.

It is a block diagram of the 1st example of the present invention. It is a block diagram of the 1st Example of this invention. It is a flowchart explaining the operation | movement of the 1st Example of this invention. 6 shows a rescan inquiry dialog displayed in the first embodiment of the present invention. 6 shows a rescan preparation completion dialog displayed in the first embodiment of the present invention. It is a flowchart explaining the detail of the page scan process step of 1st Example of this invention. (A) A schematic diagram of punch holes for explaining punch hole detection processing in the first embodiment of the present invention is shown. (B) Punch holes for explaining punch hole detection processing in the first embodiment of the present invention are shown. The signal intensity distribution on the transverse axis is shown. It is a conceptual diagram explaining the processing content of the automatic correction | amendment processing stage of 3rd Example of this invention. It is a conceptual diagram explaining the detection item in a punch hole detection process in 1st Example of this invention. It is a conceptual diagram which illustrates each item of a standard punch hole pattern in 1st Example of this invention. It is a table | surface which shows the example of description of a standard punch hole pattern table in 1st Example of this invention. 6 shows another example of a rescan inquiry dialog displayed in the first embodiment of the present invention. 6 shows another example of a rescan inquiry dialog displayed in the first embodiment of the present invention. It is a flowchart explaining the operation | movement of the 2nd Example of this invention. It is a flowchart explaining the operation | movement of the 3rd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Document reading apparatus 101 IF control part 102 Main control part 103 Document conveyance control part 104 Image reading control part 105 ADF
106 First Document Conveying Roller 107 Second Document Conveying Roller 108 Gray Reference Roller 109 Registration Sensor 110 Reading Timing Sensor 111 Scanner CCD Sensor 112 IF Control Unit 113 Image Processing Unit 114 Image Memory 115 Main Control Unit 116 Display Device 117 Input Device 118 Host Device 119 Interface 201 First document conveying roller 202 Second document conveying roller 203 Gray reference roller 204 Scanner CCD sensor 205 Reading timing sensor 206 Registration sensor 207 Document loaded on ADF 208 Distance between scanner CCD sensor and second document conveying roller L ₁
209 Distance L ₂ between the reading timing sensor and the scanner CCD sensor
901 Scanned image data 902 Document 903 Document endpoint C1
904 Document end point C2
Punch column _{a n} on 905 original
1001 Document 1002 Punch hole row on document 1003 Distance d from document edge to punch hole row d
1004 Distance _{e n} between each punch hole
1601 Schematic diagram of a document 1602 Schematic diagram of a scanned image of a document in which a slip has occurred 1603 and 1604 Punch holes before and after the portion in which the slip has occurred 1605 A portion in which an image has spread due to the slip

Claims (8)

In a document reading apparatus that reads a document having a plurality of punch holes while conveying it and processes the read image data,
Punch hole detection processing means for detecting the position of the punch hole from the read image data;
An original reading apparatus comprising: a slip detecting means for determining whether or not there is a slip during document transport based on the punch hole position information obtained by the punch hole detecting processing means. 2. The document reading apparatus according to claim 1, wherein the slip detection means includes:
Presence or absence of slipping during document conveyance,
The amount of slip when transporting the document,
An original reading apparatus characterized by determining an area in an original in which slippage has occurred during original conveyance. In a document reading apparatus that reads a document having a plurality of punch holes while conveying it and processes the read image data,
Punch hole detection processing means for detecting the position of the punch hole from the read image data;
Standard punch hole pattern that records standard punch hole position information,
By comparing the position information of the punch hole obtained by the punch hole detection processing means with the standard punch hole pattern, the presence or absence of slipping during document conveyance,
The amount of slip when transporting the document,
An original reading apparatus comprising slip detecting means for determining an area in an original in which a slip has occurred during conveyance of the original.   4. The document reading device according to claim 3, wherein the standard punch hole pattern includes: a document size; presence / absence of symmetry with respect to a center of the punch hole row; a distance between punch hole rows from a document edge; and a distance between punch holes. A document reading device described in the above.   4. The document reading apparatus according to claim 3, further comprising: inquiry means for inquiring whether or not the document needs to be rescanned when slippage is detected by the slip detection means.   4. The document reading device according to claim 3, wherein when reading a document of a plurality of pages, the slip detection page recording means for recording the page where the slip is detected by the slip detection means, and the necessity of rescanning the entire document are inquired. An original reading apparatus comprising an inquiry means. The image reading detecting unit according to claim 3, wherein an image spread detecting unit detects an image occurrence occurrence portion of the document caused by the slip from an area in the document where the slip occurs during the document transport.
An original reading apparatus comprising: an extension deletion unit that deletes an extended portion of the image detected by the image extension detection unit from the read image data by an amount of slip during the document conveyance. The document reading apparatus according to claim 4, wherein an image spread detecting unit detects an image spread occurrence portion of the document caused by the slip from an area in the document where the slip has occurred during the document transport.
An original reading apparatus comprising: an extension deletion unit that deletes an extended portion of the image detected by the image extension detection unit from the read image data by an amount of slip during the document conveyance.

Images