JP2016050061A - Reader, notifying method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique by which information about maintenance for conveyance rollers can be expected at appropriate timing, in a reader that reads a document while conveying it.SOLUTION: A scanner 100 causes a reading head 21 to read an image of a document conveyed by a conveyance part 22 and thereby captures a read image 51. On the basis of the captured image 51, the scanner 100 extracts at least an edge or angle of the document. Then, on the basis of the extracted information, the scanner acquires information about a leading-end edge 52 and a trailing-end edge 53. From the information about the leading-end edge 52 and the trailing-end edge 53 thus acquired, the scanner 100 then acquires an amount of skew change in rotation skew in which an amount of skew changes as a document is conveyed. On the basis of the acquired amount of skew change, information about maintenance for each roller pair of the conveyance part 22 is reported.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a reading device that reads an image of a document, a notification method, and a program. More specifically, the present invention relates to a reading apparatus that reads a document while conveying the document, and relates to a technique for notifying maintenance of a conveyance roller that conveys the document.

  Conventionally, in a reading apparatus that reads an image while conveying a document, problems such as skew and jam are likely to occur due to wear of a conveyance roller that conveys the document and a decrease in grip force due to adhesion of paper dust and the like. Become. Therefore, a technique is known in which the maintenance timing of the transport roller is determined, and maintenance such as replacement of the transport roller is notified as necessary.

  For example, Patent Document 1 discloses a document for informing the maintenance of the transport roller. In Patent Document 1, the number of times of use of the conveying roller is counted, and when the conveyed sheet is different from the reference sheet, the number of times of use is corrected, and based on the comparison result between the number of times of use and the limit number, the roller replacement display is performed. A configuration for determining whether or not to cause the display means to perform is disclosed.

JP 2000-264463 A

  However, the conventional technique described above has the following problems. That is, even if it is estimated that the conveyance roller is worn or the grip force is reduced due to adhesion of paper dust depending on the type of sheet, it is not possible to know whether the wear or the grip force is reduced to the extent that a conveyance failure actually occurs. Absent. For this reason, there is a possibility that the maintenance roller maintenance notification may not be at an appropriate time.

  The present invention has been made to solve the above-described problems of the prior art. That is, an object of the present invention is to provide a reading apparatus that reads a document while conveying the document, and can provide a technique that can be expected to notify the maintenance roller at an appropriate time.

  In order to solve this problem, a reading apparatus includes a conveyance roller that conveys a document, a reading unit that reads an image of a document conveyed by the conveyance roller, and a control unit, and the control unit includes the reading unit. An extraction process for extracting at least one of an edge and a corner of the document based on the reading data of the document, and information on the leading edge and the trailing edge of the document based on the information extracted in the extraction process In the rotation skew in which the skew amount changes with the conveyance of the document from the edge acquisition processing for acquiring the information and the information on the leading edge and the information on the trailing edge acquired in the edge acquisition processing. A skew change acquisition process for acquiring the skew change amount and a notification process for notifying the maintenance information of the conveyance roller based on the skew change amount acquired in the skew change acquisition process are executed. It is characterized by that.

  The reading device disclosed in this specification reads a document conveyed by a conveyance roller, and acquires information on the leading edge and trailing edge of the document based on the read data. Then, based on the acquired information on the leading edge and the information on the trailing edge, a skew change amount that is a change amount of the skew amount of the document is acquired. Further, the maintenance information of the conveying roller is notified based on the obtained skew change amount. Note that the information on the leading edge or the trailing edge corresponds to, for example, an inclination or a left / right difference. The maintenance information to be notified includes, for example, replacement and cleaning of the conveyance roller.

  In other words, the reading device disclosed in this specification acquires the skew change amount of the rotational skew from the reading result of the actually transported original, and provides maintenance information of the transport roller based on the skew change amount. Inform. For this reason, there is a high possibility of notifying the maintenance information of the transport roller in a state where there is a high possibility of actually causing a transport defect, and notification at an appropriate time can be expected.

  In the notification process, the control unit may notify maintenance information of the transport roller when the skew change amount acquired in the skew change acquisition process is greater than a first threshold. The greater the amount of skew change, the higher the possibility that the transport roller has deteriorated.

  Further, the control unit adjusts the first threshold according to the length of the document in the conveyance direction, or the skew change amount acquired in the skew change amount acquisition process is used as the skew change of the reference size. It is preferable to execute the first length-specific adjustment processing for adjusting the amount of skew change converted into the amount. As the length of the document in the conveyance direction is longer, the rotation skew advances, so that the skew change amount tends to increase. Therefore, it is preferable to determine whether to notify using the first threshold value adjusted according to the length of the document in the conveyance direction or using the skew change amount converted according to the reference size.

  In addition, the control unit, in the notification process, when the increase amount of the skew change amount acquired in the skew change amount acquisition process from the previous skew change amount is greater than a second threshold value, Information on roller maintenance may be notified. The greater the increase in the skew change amount, the higher the possibility that the transport roller will deteriorate at an early stage.

  In addition, the control unit adjusts the second threshold according to the length of the document in the conveyance direction, or uses the skew change obtained in the skew change obtaining process as the skew change of the reference size. It is preferable to execute the second length-specific adjustment process for adjusting the skew change amount converted into the amount to obtain the increase amount. A method for determining whether to notify whether the notification is made using the second threshold value adjusted according to the length in the document conveyance direction, or based on the increase amount using the skew change amount converted according to the reference size. Is preferred.

  In addition, the leading edge information and the trailing edge information acquired by the edge acquisition processing include an angle with respect to the document conveyance direction or a difference between positions of both ends in the document conveyance direction for each side. It is good to be. The degree of rotational skew can be acquired based on the angle with respect to the document transport direction or the difference between the positions of both ends in the document transport direction.

  Further, the reading device disclosed in this specification includes a plurality of the transport rollers in a direction orthogonal to the document transport direction, and the control unit performs maintenance based on the information on the leading edge and the information on the trailing edge. It is preferable to execute a first specifying process for specifying a conveyance roller that requires a maintenance roller and notify the maintenance information of the conveyance roller specified in the first identification process in the notification process. From the angle between the leading edge and the trailing edge or the difference in position between the two edges, it can be determined which of the left and right conveying rollers has deteriorated. For this reason, it is easier to identify and notify the deteriorated transport roller.

  Further, the reading device disclosed in the present specification includes a plurality of transport rollers in each of a document transport direction and a direction orthogonal to the transport direction, and the control unit uses the information extracted in the extraction process. Based on the side edge acquisition processing for acquiring the information on the side edge of the document, and the information on the side edge acquired in the side edge acquisition processing, the document conveyance direction and the direction orthogonal to the conveyance direction And a second specifying process for specifying a transport roller requiring maintenance in at least one of the above, and in the notification process, the maintenance information of the transport roller specified in the second specifying process may be notified. It can be judged from the degree of bending of the side edge whether the original has been skewed to the left or right. Then, it can be specified which of the left and right transport rollers has deteriorated. In addition, it is possible to specify which of the upstream side roller and the downstream side roller has deteriorated from the bent position in the conveying direction of the side edge. For this reason, it is easier to identify and notify the deteriorated transport roller.

  A notification method, a computer program, and a computer-readable storage medium storing the computer program for realizing the functions of the reader are also new and useful. Note that a configuration may be adopted in which some steps are performed by the reading device and the remaining steps are performed by an external device (such as a PC or a server).

  According to the present invention, it is a reading device that reads a document while conveying it, and it can be expected to notify the maintenance roller at an appropriate time.

1 is a perspective view showing a schematic appearance of a scanner according to an embodiment. It is explanatory drawing which shows the structure for the document conveyance of a scanner. It is sectional drawing which shows schematic internal structure of a scanner. It is explanatory drawing which shows the example of rotation skew. It is explanatory drawing which shows the example of a read image. It is a block diagram which shows the electric constitution of a scanner. 6 is a flowchart illustrating a procedure of document reading processing. It is a flowchart which shows the procedure of an alerting | reporting process. It is a graph which shows the example of the change of the variation | change_quantity of a left-right difference.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying a reading apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a scanner having an image reading function.

  As shown in FIG. 1, the scanner 100 according to the present embodiment is capable of rotating around a housing 60 that covers the scanner 100 main body, and a rotational axis X that is located behind and above the housing 60 and extends in the left-right direction. A document placing tray 91 supported by the housing 60 and a paper discharge tray 92 that is positioned below the housing 60 and can be inserted and removed in the front-rear direction are provided. The document placing tray 91 is provided with a guide 93 for defining the position where the document is placed. The scanner 100 also includes a button group 61 composed of various buttons (for example, each button of a start key, a stop key, and a numeric keypad) and a display unit 62 composed of a liquid crystal display on the upper surface of the housing 60. An operation panel 40 is provided.

  In the following, as shown in FIG. When facing the paper discharge tray 92, the left hand side is the left and the right hand side is the right. Further, the scanner 100 conveys the document from the document placement tray 91 side toward the paper discharge tray 92 side. That is, in the document transport direction, the document placement tray 91 side is the upstream side, and the paper discharge tray 92 side is the downstream side.

  As shown in FIG. 2, the scanner 100 according to the present embodiment includes a reading head 21 and a conveyance unit 22 inside a housing 60. Then, the scanner 100 reads the image of the document G conveyed by the conveyance unit 22 with the reading head 21. The reading head 21 has a light emitting element and a light receiving element, irradiates light to the opposed portions, and outputs a signal based on the amount of received light. Then, the scanner 100 acquires image data based on the output signal of the reading head 21. The reading method of the scanner 100 of this embodiment may be a CIS method or a CCD method. The reading head 21 is an example of a reading unit.

  The conveyance unit 22 of the scanner 100 according to the present embodiment includes roller pairs 41, 42, 43, and 44 as shown in FIG. Each of the roller pairs 41, 42, 43, 44 is a pair of a driving roller driven by a motor (not shown) and a driven roller facing the driving roller. The driving roller and the driven roller of each roller pair 41, 42, 43, 44 are arranged in contact with each other in a direction (vertical direction in FIG. 1) perpendicular to the conveying direction. Each of the roller pairs 41, 42, 43, 44 transports the document with the document between the driving roller and the driven roller. Each roller of the transport unit 22 is an example of a transport roller.

  The driving roller of the roller pair 41 and the driving roller of the roller pair 42 are provided on a common rotating shaft and rotate simultaneously. The driven roller of the roller pair 41 and the driven roller of the roller pair 42 are provided on a common rotating shaft and rotate simultaneously. The roller pair 41 and the roller pair 42 are formed at positions separated from each other in the axial direction (left-right direction) of the rotation shaft. The roller pair 43 and the roller pair 44 have the same configuration as the roller pair 41 and the roller pair 42. The roller pair 41 and the roller pair 43, and the roller pair 42 and the roller pair 44 are disposed at substantially the same position in the left-right direction.

  The rotation axes of the roller pairs 41, 42, 43, 44 are parallel to each other and are arranged in parallel with the longitudinal direction of the reading head 21. The conveyance direction of the original G is the direction from the roller pair 41, 42 toward the roller pair 43, 44. The roller pairs 41 and 42 are arranged upstream of the reading head 21 in the conveyance direction of the original G. The roller pairs 43 and 44 are arranged on the downstream side of the reading head 21 in the conveyance direction of the original G.

  Next, the internal configuration of the scanner 100 will be described with reference to FIG. FIG. 3 is a view showing a cross section viewed from the right in FIG. As shown in FIG. 3, the scanner 100 includes a paper feed roller 26, a white plate 23 facing the reading head 21, and two sensors (sensor 27 and sensor 27) that output signals according to the presence or absence of the document G at each position. Sensor 28). The sensor 27 outputs a signal corresponding to the presence or absence of the document G placed on the document placement tray 91. The sensor 28 outputs a signal corresponding to the presence or absence of the document G at a position downstream of the sensor 27 and upstream of the reading head 21 in the conveyance direction of the document G. The paper feed roller 26 feeds the originals G placed on the original placement tray 91 one by one toward the reading head 21.

  When the scanner 100 receives an instruction to read a document, the scanner 100 transports the document G fed from the document placement tray 91 by the transport unit 22 and causes the reading head 21 to read the image of the document G. Thereby, the scanner 100 acquires a read image. Further, the scanner 100 generates image data for output based on the acquired read image, and outputs the generated image data to an instructed output destination.

  Reading by the reading head 21 is started before the leading edge of the original G reaches the position of the reading head 21 based on the output signal of the sensor 28, and the rear end of the original G or the set reading range is determined by the reading head 21. Exited after passing position. When there is no document G at a position facing the reading head 21, the reading head 21 reads the white plate 23. Accordingly, a shadow image appears at the boundary between the outer periphery of the document G and the white plate 23 in the read image. The scanner 100 can acquire the position of the outer periphery of the document G in the read image based on the position of the shadow image.

  As shown in FIG. 3, the reading head 21 of the scanner 100 of this embodiment reads the lower surface of the original G upward. Accordingly, the original G is set on the original placing tray 91 with the surface to be read facing downward. Further, the guide 93 (see FIG. 1) provided on the document placing tray 91 aligns the document G so that the center position of the document comes to the center of the roller pair 41 and the roller pair 42 in the left-right direction. Set. Therefore, if there is no difference due to roller deterioration or the like, the original G is conveyed by the roller pair 41 and the roller pair 42 substantially equally on the left and right.

  Here, when the document G is transported by the transport unit 22, the document G may be inserted with an inclination with respect to the reading head 21. In addition, there is a possibility that a difference in right and left in the grip force of the roller pair may occur between the roller pairs of the transport unit 22 due to wear state, paper dust adhesion, or the like. If the left and right difference in the traveling speed of the document G occurs due to the difference in grip force between the roller pairs, the skew amount of the document is likely to change during document transportation. Hereinafter, the skew in which the skew amount changes as the document is conveyed is referred to as “rotating skew”. On the other hand, if there is no left-right difference in the grip force of each roller pair of the conveyance unit 22, even if the original G is inserted with an inclination, the skew amount of the original does not change during the conveyance.

  When the rotation skew occurs, for example, as illustrated in FIG. 4, the inclination of the original G with respect to the reading head 21 is different at the start of conveyance of the original G and at the end of conveyance. In the example of this figure, as indicated by a two-dot chain line in the figure, the leading edge of the document G is read almost parallel to the reading head 21, and as shown by a solid line in the figure, the trailing edge of the document G is read. It is read while being tilted with respect to the head 21. As described above, when rotation skew occurs during conveyance during reading, the shape of the document included in the read image is different from the actual shape of the document.

  An example of the read image 51 when the rotation skew occurs is shown in FIG. When the inclination of the original G changes during reading due to rotation skew, the outer periphery of the original portion in the read image 51 has a distorted shape in which the leading edge 52 and the trailing edge 53 are not parallel. For example, as shown in FIG. 4, when the original G is conveyed to the left, the read image 51 read from the lower side by the reading head 21 has a shape bent to the right as shown in FIG. When the scanner 100 according to the present embodiment determines that a predetermined or higher rotational skew has occurred based on the read image 51, the scanner 100 determines that the roller included in the transport unit 22 needs to be maintained, and prompts maintenance. I do.

  Next, the electrical configuration of the scanner 100 will be described. As shown in FIG. 6, the scanner 100 includes a controller 30 including a CPU 31, a ROM 32, a RAM 33, an NVRAM (nonvolatile RAM) 34, and an ASIC 35. The scanner 100 includes a reading head 21, a transport unit 22, a network interface (IF) 37, a USB interface (IF) 38, and an operation panel 40, which are electrically connected to the controller 30. Yes.

  The ROM 32 stores various control programs for controlling the scanner 100, various settings, initial values, and the like. The RAM 33 is used as a work area from which various control programs are read, or as a storage area for temporarily storing data. The CPU 31 controls each component of the scanner 100 while storing the processing result in the RAM 33 or the NVRAM 34 according to the control program read from the ROM 32.

  The CPU 31 is an example of a control unit. The controller 30 may be a control unit, and the ASIC 35 may be a control unit. Note that the controller 30 in FIG. 6 is a general term that summarizes hardware used for controlling the scanner 100, such as the CPU 31, and does not necessarily represent a single piece of hardware that actually exists in the scanner 100.

  The network interface 37 is hardware for communicating with a device connected via a network using a LAN cable or the like. The USB interface 38 is hardware for communicating with a device connected via a USB cable or the like. The operation panel 40 displays a notification to the user and accepts an input operation by the user.

  Next, a document reading process, which is a process for realizing the above-described reading operation in the scanner 100 of the present embodiment, will be described with reference to a flowchart of FIG. This document reading process is executed by the CPU 31 when an instruction input for starting document reading is received.

  In the document reading process, the scanner 100 first starts conveying a document (S101). Then, based on the output signal of the sensor 28 (see FIG. 3) and the like, it is determined that the leading edge of the document has reached the reading start position, and then the reading head 21 starts reading (S102). The reading start position is upstream of the reading position of the reading head 21 in the document transport direction.

  Based on the output signal of the reading head 21, the scanner 100 sequentially acquires the read images 51 from the front end side as shown in FIG. Then, the scanner 100 starts extracting the edge of the document based on the read portion of the read image 51 (S103). For example, the scanner 100 can extract the edge of the document based on the position of the shadow image that appears around the document portion as described above. The process of S103 is an example of an extraction process.

  Then, the scanner 100 determines whether or not the leading edge of the document has reached the reading position of the reading head 21 (S104). That is, it is determined whether an edge that can be determined as a result of reading the leading edge of the document has been extracted. When it is determined that the edge due to the leading edge of the document has not been extracted and the leading edge of the document has not reached the reading position of the reading head 21 (S104: NO), the conveyance and reading of the document and the extraction of the edge are performed. Continue further.

  When it is determined that the leading edge of the document has reached the reading position of the reading head 21 (S104: YES), the scanner 100 acquires position information of the leading edge 52 of the document from the extracted edge. Then, the scanner 100 acquires the left-right difference of the front end side 52 based on the read information on the front end side 52 (S105).

  For example, as shown in FIG. 5, the left-right difference is a difference in position in the document reading direction between point A and point B, which are corners at both ends of the leading edge 52. In the example of FIG. 5, the scanner 100 obtains the distances dA and dB from the upper end of the read image 51 to the points A and B, respectively, and sets dA−dB as the left-right difference of the tip side 52. The left-right difference of the leading edge 52 acquired in S105 is an example of information on the leading edge of the document, and the process of S105 is an example of an edge acquisition process.

  Next, the scanner 100 determines whether or not the reading of the document is completed (S106). When the trailing edge of the document passes the reading position of the reading head 21 and the reading of the document is completed, an edge formed by the trailing edge 53 of the scanned image 51 is extracted as shown in FIG. If it is determined that the reading of the original has not been completed (S106: NO), the conveyance and reading of the original and the extraction of the edge are further continued.

  When it is determined that the reading of the document has been completed (S106: YES), the scanner 100 acquires position information of the trailing edge 53 of the document from the extracted edge. Then, the scanner 100 acquires the left-right difference of the rear end side 53 based on the read information of the rear end side 53 (S107). Note that the scanner 100 also executes a process of outputting the image data based on the acquired read image 51 to the output destination specified by the received read instruction in parallel with the processes after S107.

  For example, as illustrated in FIG. 5, the scanner 100 obtains distances dC and dD from the respective points C and D, which are corners on both ends of the rear end side 53, to the lower end of the read image 51, and dD−dC. Is the left-right difference of the rear end side 53. By subtracting the left / right difference between the left / right difference of the front end side 52 and the left / right difference of the rear end side 53, the comparison including the direction of inclination can be made. For example, if both the leading edge 52 and the trailing edge 53 are lowered to the right, both (dA−dB) and (dD−dC) are positive values. The sign may be reversed without changing the left and right of the subtraction.

  Alternatively, the scanner 100 may use a difference in distance from the upper end of the read image 51 to the points C and D as the left-right difference of the rear end side 53. In this case, it is not necessary to reverse the sign. The left-right difference of the trailing edge 53 acquired in S107 is an example of information on the trailing edge of the document, and the process of S107 is an example of the edge acquisition process.

  Next, the scanner 100 calculates the amount of change in the left / right difference based on the difference between the left / right difference of the front edge 52 acquired in S105 and the left / right difference of the rear edge 53 acquired in S107 (S108). If no rotational skew occurs during reading of the document, the leading edge 52 and the trailing edge 53 are substantially parallel. If the front end side 52 and the rear end side 53 are substantially parallel, the left-right difference of the front end side 52 and the left-right difference of the rear end side 53 are substantially equal, so the change amount of the left-right difference is very small. On the other hand, when rotation skew of the document occurs, the greater the degree of rotation skew, the greater the amount of change between the left / right difference of the leading edge 52 and the left / right difference of the trailing edge 53. The change amount of the left-right difference is an example of the skew change amount of the rotational skew, and the process of S108 is an example of the skew change acquisition process.

  Further, the scanner 100 acquires the length of the document in the transport direction (reading direction) based on the read image 51 (S109). The scanner 100, for example, in the transport direction, the distance between point A and point C, the distance between point B and point D, or the distance between point A and point C and the distance between point B and point D Is the original length. Note that the scanner 100 may acquire the length of the document based on the output signal of the sensor 28.

  Then, the scanner 100 adjusts the change amount of the left / right difference acquired in S108 according to the length of the original acquired in S109 (S110). Specifically, the scanner 100 adjusts by converting the change amount of the left / right difference by the length of the document to convert it into the change amount of the left / right difference in the reference size document. Further, the scanner 100 may convert the A4 size or the like as the reference size by multiplying the change amount of the left / right difference by (reference size / document length). If the length of the document is long, the amount of change in the left / right difference will increase as a result even if the document is rotated at the same rate. Therefore, the scanner 100 converts the change amount of the left-right difference and acquires an adjustment value that is a normalized change amount regardless of the length of the document. The process of S110 is an example of a first length-specific adjustment process.

  For example, if the scanner 100 includes an ultrasonic sensor and can acquire the type of document such as paper thickness and quality, the amount of change in the left-right difference may be further adjusted according to the acquired type of document. In this case, in S110, for example, a predetermined coefficient is multiplied for each document type, and the change amount of the left-right difference is converted into a normalized change amount regardless of the document type. Note that the paper thickness and quality may be input by the user. The process of S110 in this case is also an example of the first type-specific adjustment process.

  Next, based on the adjustment value of the change amount of the left-right difference acquired in S110, a notification process for notifying maintenance information about each roller of the transport unit 22 is executed as necessary (S112). The notification process will be described with reference to the flowchart of FIG.

  In the notification process, the scanner 100 first determines whether or not the adjustment value for the change amount of the left-right difference acquired in S110 of the document reading process in FIG. 7 is large (S201). For example, the scanner 100 determines that the amount of change is large when the absolute value of the amount of change is greater than a predetermined first threshold. If it is determined that the amount of change is not large (S201: NO), the scanner 100 determines that there is no rotational skew that causes notification. If there is no rotational skew, it is estimated that the difference in the degree of deterioration between the roller pairs is not large. Therefore, when the amount of change is not large, the scanner 100 determines that it is not necessary to notify the maintenance of the transport unit 22 and ends the notification process.

  On the other hand, when it is determined that the amount of change in the left / right difference is large (S201: YES), the scanner 100 notifies the maintenance of the transport unit 22. In particular, according to the direction and position of the change, as will be described later, a pair of rollers to be maintained is specified, and notification is given to prompt the cleaning or replacement of the corresponding pair of rollers. Note that the notification corresponds to, for example, message display on the operation panel 40 (see FIG. 6) or voice guidance.

  Therefore, when notifying the maintenance of the conveyance unit 22, the scanner 100 identifies a roller pair that is estimated to have deteriorated. For this purpose, the scanner 100 first acquires the direction of change in the conveyance direction based on the sign of the change amount of the left-right difference after conversion acquired in S110 of the document reading process. The direction of change is the left-right direction of the document transport position at the end of transport compared to the start of transport.

  For example, as shown in FIG. 5, when a read image 51 that is shifted to the right with respect to the transport direction from the front end side 52 side toward the rear end side 53 side is acquired, as described above, in FIG. It can be seen that the original was gradually transported toward the left side. In the following, it is assumed that the left side of the document is conveyed to the left side and the right side of the document is conveyed to the right side. For example, if the left side of the manuscript is slower than the right side of the manuscript, the left turn will occur.

  Then, the scanner 100 determines whether or not the conveyance direction is a left turn (S203). When it is determined that the sheet is conveyed to the left (S203: YES), the scanner 100 has a lower grip force of the right roller pair 42, 44 than the left roller pair 41, 43 (see FIG. 2). I guess. This is because when the document is conveyed by a pair of rollers having a reduced grip force, the slip of the document is likely to occur, and the document tends to travel faster than the pair of rollers having a large grip force. Therefore, the scanner 100 specifies that the right pair of rollers 42 and 44 has deteriorated (S204).

  On the other hand, when it is determined that it is not a left turn (S203: NO), that is, when it is a right turn, the grip force of the left roller pair 41, 43 is lower than that of the right roller pair 42, 44. Can be guessed. Therefore, the scanner 100 specifies that the left roller pair 41, 43 has deteriorated (S205). The process of S204 and the process of S205 are examples of the first specifying process.

  Next, the scanner 100 acquires information on the left and right side edges 54 and 55 based on the read image 51 as shown in FIG. 5 (S207). For example, the scanner 100 acquires the positions of the side edges 54 and 55 of the document image by extracting edges based on the shadow image appearing in the read image 51. In S207, the scanner 100 acquires information on the bending position of at least one of the side end sides 54 and 55 as information on the side end sides 54 and 55. The bending position is, for example, a place where the curvature is maximum. The process of S207 is an example of a side edge acquisition process.

  Then, the scanner 100 determines whether or not the bending position of the side edges 54 and 55 is above the read image 51 based on the information of the side edges 54 and 55 acquired in S207 (S209). . For example, based on the read image 51, the scanner 100 sets a position where the side edges 54 and 55 start to be separated from a line orthogonal to the tip edge 52, or a position separated by a predetermined distance or more as a bending position. Then, the scanner 100 determines whether or not the bending position is above the leading edge 52 based on whether the acquired bending position is close to the leading edge 52 or the trailing edge 53.

  When it is determined that the bending position is close to the top side 52 and above (S209: YES), the scanner 100 estimates that the grip force of the upstream roller pair 41, 42 is reduced. This is because there is a high possibility that a rotational skew has occurred particularly during conveyance by only the upstream roller pair 41 and 42 immediately after the conveyance is started. That is, if the bending position is above, the scanner 100 specifies that the upstream roller pair 41, 42 has deteriorated (S210).

  On the other hand, when it is determined that the bending position is close to the rear end side 53 and not above (S209: NO), the scanner 100 estimates that the grip force of the downstream roller pair 43, 44 is reduced. Therefore, the scanner 100 identifies that the downstream roller pair 43, 44 has deteriorated (S211). The process of S210 and the process of S211 are examples of the second specifying process.

  Note that the procedure for obtaining the information on the side edges 54 and 55 in S207 may be executed prior to S203, and the left and right judgments in S203 may also be performed based on the information on the side edges 54 and 55. That is, the bending direction may be determined based on whether the side edges 54 and 55 are bent in the left or right direction. In this case, the procedure for obtaining the information about the side edges 54 and 55 is an example of the second specifying process and an example of the first specifying process.

  Since the scanner 100 has identified the roller pair that is assumed to have deteriorated from the results of S204, S205, S210, and S211, the scanner 100 issues a notification prompting cleaning or replacement of the specified roller pair (S213). End the process. For example, when the scanner 100 identifies that the right roller pair 42, 44 has deteriorated in S204, and the upstream roller pair 41, 42 has deteriorated in S210, the scanner 100 To notify the cleaning or replacement of the roller pair 42 on the right side.

  After the notification process, returning to FIG. 7, the presence / absence of the next document is determined based on the output signal of the sensor 27 (S114). If it is determined that there is a next original (S114: YES), the process returns to S101 to start conveying and reading the next original. On the other hand, if it is determined that there is no next original (S114: NO), the original reading process is terminated.

  In S201 of the notification process, the scanner 100 determines whether or not rotational skew has occurred based on whether or not the absolute value of the change in the left-right difference after conversion is greater than a predetermined first threshold value. I decided to judge. Instead, the scanner 100 compares the change amount of the left-right difference after conversion with the past change amount, and determines whether or not the rotation skew has occurred based on the increase amount from the past change amount. May be performed.

  In that case, the scanner 100 stores, in the NVRAM 34 or the like, the amount of change in the left-right difference after conversion or the amount of increase obtained in S110 when the document reading process is executed. Then, in S201 of the notification process, the past change amount or increase amount is read from the NVRAM 34 or the like, and it is determined whether or not the increase amount of the current change amount is larger than the second threshold value. Even in this case, it is desirable to acquire the increase amount based on the converted amount of difference between the left and right according to the length of the document in the conveyance direction or the type of the document.

  For example, the scanner 100 stores the amount of change for the past month, and determines that rotation skew has occurred when the amount of increase from the average value of past changes is greater than a predetermined second threshold. To do. Further, for example, it is determined whether or not the increase amount that is the difference between the change amount between the previous time and the current time is larger than the difference between the previous time and the previous time. Further, for example, it is determined whether or not the difference between the change amount predicted as the current change amount and the current change amount is large based on the increasing tendency of the change amount of the left-right difference until the previous time.

  For example, as shown by a solid line in FIG. 9, the increasing tendency is acquired from a plurality of past changes in the left / right difference. Then, it is determined whether or not the current change amount of the left-right difference is larger than a value (indicated by a broken line in FIG. 9) where the difference from the change amount predicted based on the increasing tendency is a second threshold value. . If the amount of change this time is less than or equal to the broken line, it is determined that no rotational skew has occurred. On the other hand, when the broken line is exceeded as indicated by a point Z shown in FIG. 9, it is determined that rotational skew has occurred.

  As described above in detail, the scanner 100 of this embodiment reads an image of a document while conveying the document. Based on the acquired read image 51, the positions of the left and right ends of the front end side 52 and the rear end side 53 are acquired. Further, for the front end side 52 and the rear end side 53, a left-right difference that is a difference between the positions of the left and right ends is acquired, and a change amount between the left-right difference of the front end side 52 and the left-right difference of the rear end side 53 is acquired. Then, the maintenance of the conveyance roller is notified based on the change amount of the left / right difference. That is, since it is determined whether or not the maintenance of the transport roller is necessary based on the actual transport result, it is possible to expect notification at an appropriate time for the maintenance of the transport roller.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, the present invention is not limited to a scanner, and can be applied to any apparatus having an image reading function that reads a document while conveying it, such as a copying machine, a multifunction machine, and a FAX apparatus.

  Further, the number and arrangement of the transport rollers are not limited to the example of this embodiment. For example, more roller pairs may be provided, or the left and right roller pairs may be driven separately. In this embodiment, the lower surface of the original G is read, but the present invention is not limited to this. In the scanner configured to read from the upper side, the bending direction of the document and the bending direction of the read image 51 are the same direction.

  Further, for example, in the embodiment, the left and right differences are used as the information on the leading edge and the information on the trailing edge. That is, the presence / absence of rotation skew is determined based on the amount of change between the left / right difference of the front end side 52 and the left / right difference of the rear end side 53, but instead of the left / right difference, the front end side 52 and the rear end side are replaced. An inclination angle of 53 may be used. In this case, the angle difference is an example of the skew change amount. Then, when the difference in angle is larger than the threshold value, the scanner 100 may notify the maintenance of the conveyance roller. Further, for example, the scanner 100 can determine whether it is a right turn or a left turn based on the angle of the front end side 52 and the angle of the rear end side 53.

  Also, for example, the change amount of the left-right difference is converted based on the length of the document in the conveyance direction or the type of the document. Instead of converting the change amount of the left-right difference, the first threshold value and the second threshold value are converted. May be adjusted. For example, the threshold value multiplied by a predetermined coefficient may be compared with the amount of change in the left-right difference based on the length of the document in the conveyance direction. Further, the threshold value multiplied by a predetermined coefficient may be compared with the change amount of the left / right difference based on the type of document.

  Further, for example, the conversion of the change amount and the adjustment of the threshold value based on the length of the document in the conveyance direction or the document type may not be performed. That is, S109 and S110 are not necessary.

  In the notification process, the roller pair to be maintained is specified for the left and right and the upstream and downstream, but may not be specified. In other words, if YES is determined in S201, the notification may be made. Further, only the left and right sides may be specified, or only the upper and lower sides may be specified. However, maintenance will be easier if they are specifically identified.

  In this embodiment, the determination and notification of rotation skew is performed during the document reading process, but the execution timing is not limited to this. For example, the notification process may be executed after the reading job ends. Further, for example, the necessity of notification may be stored in the NVRAM 34 or the like, and after receiving the next reading job, it may be notified before the execution.

  The processing disclosed in the embodiments may be executed by a single CPU, a plurality of CPUs, hardware such as an ASIC, or a combination thereof. Further, the processing disclosed in the embodiment can be realized in various modes such as a recording medium or a method recording a program for executing the processing.

21 Reading Head 22 Conveying Unit 31 CPU
41, 42, 43, 44 Roller pair 100 Scanner

Claims (10)

A transport roller for transporting the document;
A reading unit for reading an image of a document conveyed by the conveyance roller;
A control unit;
With
The controller is
An extraction process for extracting at least one of an edge and a corner of the document based on data read by the reading unit;
An edge acquisition process for acquiring information on the leading edge and information on the trailing edge of the document based on the information extracted in the extraction process;
The skew change for acquiring the skew change amount in the rotational skew in which the skew amount changes with the conveyance of the document from the information on the leading edge and the information on the trailing edge acquired in the edge acquisition processing. Quantity acquisition processing,
A notification process for notifying information on maintenance of the transport roller based on the skew change obtained in the skew change obtaining process;
The reading apparatus characterized by performing. The reading device according to claim 1,
The controller is
In the notification process, when the skew change amount acquired in the skew change amount acquisition process is larger than a first threshold, the maintenance information of the transport roller is notified. The reading device according to claim 2,
The controller is
The first threshold is adjusted according to the length of the document in the conveyance direction, or the skew change obtained by converting the skew change obtained in the skew change acquisition process into the skew change of the standard size A reading apparatus that executes a first length-specific adjustment process for adjusting the amount. The reading apparatus according to any one of claims 1 to 3,
The controller is
In the notification process, when the increase amount of the skew change amount acquired in the skew change amount acquisition process from the past skew change amount is larger than a second threshold, the maintenance information of the transport roller is notified. A reading device. The reading device according to claim 4,
The controller is
The second threshold is adjusted according to the length of the document in the conveyance direction, or the skew change obtained by converting the skew change obtained in the skew change acquisition process into the skew change of the reference size A reading apparatus that performs second length-specific adjustment processing for adjusting an amount to obtain an increase amount. In the reading device according to any one of claims 1 to 5,
The information on the leading edge and the trailing edge acquired by the edge acquisition processing includes an angle with respect to the document conveyance direction or a difference between positions of both ends in the document conveyance direction for each side. A reader characterized by. In the reading device according to any one of claims 1 to 6,
A plurality of the transport rollers are provided in a direction orthogonal to the document transport direction,
The controller is
From the information on the leading edge and the information on the trailing edge, a first specifying process for specifying a transport roller that requires maintenance is performed.
In the notification process, information on maintenance of the conveyance roller specified in the first specification process is notified. The reading device according to any one of claims 1 to 7,
A plurality of the transport rollers are provided in each of a document transport direction and a direction orthogonal to the transport direction;
The controller is
A side edge acquisition process for acquiring information on a side edge of the document based on the information extracted in the extraction process;
A second identification process for identifying a conveyance roller that requires maintenance in at least one of the document conveyance direction and the direction orthogonal to the conveyance direction from the information on the side edge acquired in the side edge acquisition process;
And
In the notification process, information on maintenance of the conveyance roller specified in the second specification process is notified. A method for notifying information on maintenance of the conveyance roller of a reading device that reads a document conveyed by a conveyance roller,
An extraction step for extracting at least one of an edge and a corner of the document based on a reading result of the document conveyed by the conveyance roller;
An edge obtaining step for obtaining information on the leading edge and the trailing edge of the document based on the information extracted in the extracting step;
The skew change for acquiring the skew change amount in the rotational skew in which the skew amount changes as the document is conveyed from the information on the leading edge and the information on the trailing edge acquired in the edge acquisition step. A quantity acquisition step;
A notifying step for notifying information on maintenance of the transport roller based on the skew change obtained in the skew change obtaining step;
A method for notifying information on maintenance of the conveying roller, comprising: An information processing device that communicates with a reading device that reads a document conveyed by a conveyance roller;
An extraction process for extracting at least one of an edge and a corner of the document based on the result of reading the document by the reading device;
An edge acquisition process for acquiring information on the leading edge and information on the trailing edge of the document based on the information extracted in the extraction process;
The skew change for acquiring the skew change amount in the rotational skew in which the skew amount changes with the conveyance of the document from the information on the leading edge and the information on the trailing edge acquired in the edge acquisition processing. Quantity acquisition processing,
A notification process for notifying information on maintenance of the transport roller based on the skew change obtained in the skew change obtaining process;
A program characterized by having executed.

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