JP2018203503A - Image reading device - Google Patents

Abstract

To solve the problem that a document which cannot be conveyed by a conveyance roller cannot be conveyed.SOLUTION: An image reading device includes a document tray, a reading section, a separation section, a conveyance section, a plurality of detection sections which are arranged at a plurality of roller positions and output an output value corresponding to presence/absence of the manuscript, and a control section, where the control section executes acquisition processing of acquiring the plurality of output values at the roller positions from the plurality of detection sections, conveyance determination processing of determining whether or not the document can be conveyed based on the plurality of output values, and re-conveyance processing of executing a re-conveyance operation of conveying the document to the separation section when it is determined that the document cannot be conveyed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image reading apparatus.

  An image reading apparatus that reads an image of a document while conveying the document is known.

  The image reading apparatus described in Patent Document 1 detects that the shape of a sheet fed into the apparatus by the sheet feeding unit is an abnormal shape, and controls the sheet discharge speed based on the detected result. .

  In general, the image reading apparatus separates a plurality of documents into one document by a separation roller provided at the center in the main scanning direction orthogonal to the conveyance direction. The image reading apparatus conveys one separated original to a reading unit by a plurality of conveyance rollers. It is desirable that the plurality of transport rollers be arranged apart from each other in the main scanning direction in order to prevent the occurrence of skew. For this reason, the conveyance rollers are provided in the vicinity of both ends in the main scanning direction of the smallest standard size document that can be conveyed.

JP 2010-116235 A

  A separation roller arranged in the center of the main scanning direction and two transport rollers arranged apart from each other in the main scanning direction, and detects that the shape of the document is an abnormal shape as in Patent Document 1. Consider a case where the image reading apparatus that changes the document discharge speed reads a specific document. The shape of the specific document is a distorted shape that shortens in the main scanning direction near the center in the conveyance direction, or a shape that includes a hole in the document. Since the specific document is a document in which no document exists at the position of the transport roller in the main scanning direction, the image reading apparatus cannot be transported by the transport roller.

  In this case, the image reading apparatus detects whether or not the shape of the fed sheet is an abnormal shape, and controls only the document discharge speed based on the detection result. In the case of a document, the document could not be conveyed.

  Therefore, the present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an image reading apparatus capable of transporting a document by a separation roller when the document cannot be transported by a transport roller.

  In order to achieve the above object, according to the first aspect of the present invention, the image reading device includes a document tray that supports the document, a reading unit that reads an image of the document along the main scanning direction, and a main scanning direction. A separation unit that includes a separation roller disposed at a central position of the document tray, and that separates the documents supported on the document tray one by one; and a plurality of components disposed symmetrically about the central position in the main scanning direction Transporting the original separated by the separation unit to the reading unit along a conveyance direction that is orthogonal to the main scanning direction and is a direction in which the original is conveyed from the document tray to the reading unit. And a plurality of roller positions that are positions of the plurality of transport rollers in the main scanning direction, and are disposed at positions upstream of the position of the transport rollers in the transport direction. A plurality of detection units that output output values corresponding to the presence or absence of a document; and a control unit, wherein the control unit obtains a plurality of output values at the plurality of roller positions from the plurality of detection units, respectively. Processing, conveyance determination processing for determining whether the conveyance unit can convey the document separated by the separation unit based on the plurality of output values, and the conveyance unit conveys the document separated by the separation unit When it is determined that it cannot be performed, a re-conveying process for executing a re-conveying operation for conveying the original separated by the separating unit to the separating unit is executed.

  According to a specific aspect of the present invention, each detection unit of the plurality of detection units detects whether or not there is a document in a predetermined range centered on each roller position where the detection units are arranged in the main scanning direction. A corresponding output value is output, and the conveyance determination process includes an original non-determination process for determining whether or not the plurality of output values are all output values corresponding to no original, and the plurality of output values are all When the output value corresponds to the absence of a document, the transport unit determines that the document separated by the separation unit cannot be transported, and one of the plurality of output values is an output value corresponding to the presence of the document. At a certain time, it is determined that the transport unit can transport the document separated by the separation unit, and the transport roller is in a direction orthogonal to a transport surface constituting a transport path for guiding the document separated by the separation unit. Placed opposite A pair of conveying rollers, wherein the predetermined range includes a nip region in the main scanning direction formed on the pair of conveying rollers.

  According to a specific aspect of the present invention, the reading unit includes a discharge tray that supports the document read by the reading unit, and a discharge roller that is disposed at a position downstream of the reading unit in the transport direction. A paper discharge unit that transports the document read by the paper discharge tray and a display unit, wherein the acquisition process acquires the plurality of output values from the plurality of detection units at predetermined time intervals, respectively. In the re-conveying process, the control unit conveys the leading end portion in the conveyance direction of the document conveyed by the separation unit to the position of the discharge roller in the conveyance direction from when the document is conveyed by the separation unit. The re-conveyance is performed when the plurality of output values acquired at the predetermined time interval are all output values corresponding to the absence of a document until the separation roller is rotated by a rotation amount corresponding to the conveyance amount. A stop process of stopping the work, when the user stops the re-feeding operation, executes a display process of displaying the display data indicating the abnormal transport of the document on the display unit.

  According to a specific aspect of the present invention, the control unit rotates corresponding to a conveyance amount in which a leading end portion in the conveyance direction of the document separated by the separation unit is conveyed to the position of the paper discharge roller in the conveyance direction. When the transport roller is rotated by an amount, an end process for ending the transport determination process is executed.

  According to a specific aspect of the present invention, the image reading apparatus is disposed at the position of the detection unit in the transport direction, is disposed at the center position in the main scanning direction, and is separated by the separation unit in the transport direction. A document edge detection unit for detecting the trailing edge of the document is provided, and the end processing ends the conveyance determination process when the document edge detection unit detects the document trailing edge.

  In a specific aspect according to claim 6, the number of the plurality of detection units is two, the number of the plurality of transport rollers is two, and the control unit is the one of the plurality of detection units. A setting process in which a detection unit that has output an output value corresponding to the absence of a document is set as a first detection unit, and a detection unit that is not the first detection unit among the plurality of detection units is set as a second detection unit. The conveyance determination process is executed after the setting process is executed, and before the output value corresponding to the presence of the document is acquired from the first detection unit, the output corresponding to the absence of the document is output from the second detection unit. When the value is acquired, the conveyance unit determines that the original separated by the separation unit cannot be conveyed, and when the output value corresponding to the presence of the original is obtained from the first detection unit, the conveyance unit It is determined that the document separated by the separation unit can be conveyed.

  According to the first aspect of the present invention, the acquisition process acquires a plurality of output values at a plurality of roller positions from the plurality of detection units, respectively, and the conveyance determination process conveys the original separated by the separation unit. Judgment is made based on a plurality of output values, and the re-conveying process conveys the original separated by the separating unit to the separating unit when the conveying unit determines that the original separated by the separating unit cannot be conveyed. Let Accordingly, it is determined whether or not the document cannot be transported by the transport roller, and even if the document cannot be transported by the transport roller, the document can be transported by being transported by the separation unit.

  According to a specific aspect of the present invention, the document non-determination process determines whether or not all the plurality of output values are output values corresponding to the document non-existence, and the conveyance determination process includes all the plurality of output values. When the output value corresponds to the absence of a document, the transport unit determines that the document separated by the separation unit cannot be transported, and any one of the plurality of output values is an output value corresponding to presence of the document Therefore, the conveyance unit determines that the original separated by the separation unit can be conveyed, and the predetermined range includes a nip region in the main scanning direction formed on the pair of conveyance rollers. Therefore, an output value corresponding to the presence / absence of the document is acquired in a predetermined range including the nip region of the pair of transport rollers in the main scanning direction, and it is determined whether or not the plurality of output values are all output values corresponding to the absence of the document. Therefore, it can be determined whether or not the document can be accurately conveyed by the conveyance roller.

  According to a specific aspect of the present invention, the stop process is performed such that the leading end in the document transport direction is transported to the position of the paper discharge roller in the transport direction from when the document is transported by the separation unit in the re-transport process. Until the separation roller is rotated by the rotation amount corresponding to the conveyance amount, when the plurality of output values acquired at a predetermined time interval are all output values corresponding to no document, the re-conveying operation is stopped and displayed. In the processing, when the re-conveying operation is stopped, display data indicating an abnormality in conveying the original is displayed. Therefore, detection is performed at predetermined time intervals from when the document is conveyed by the separation unit to when the separation roller is rotated by a rotation amount corresponding to the conveyance amount for conveying the leading end of the document to the position of the paper discharge roller. When all of the output values are output values corresponding to the absence of a document, the re-conveying operation is stopped and display data indicating a document conveyance abnormality is displayed, so that the document cannot be conveyed by the separation unit. The document can be stopped, and the user can be notified of the conveyance error of the document.

  According to a specific aspect of the present invention, the end processing is performed when the transport roller is rotated by a rotation amount corresponding to the transport amount in which the leading end portion in the transport direction of the document is transported to the position of the discharge roller in the transport direction. Finally, the conveyance determination process is terminated. Therefore, when the leading edge of the document is transported to the position of the discharge roller, the document is transported by the transport roller and the discharge roller, so that the document that cannot be transported only by the transport roller can be transported by the discharge roller. The document can be conveyed without erroneously determining that the document cannot be conveyed.

  According to a specific aspect of the present invention, the end process ends the conveyance determination process when the document end detection unit detects the trailing end of the document. Therefore, when the document edge detection unit located at the same position as the detection unit in the transport direction detects the trailing edge of the document, the document is not detected by the detection unit. Can be transported.

  According to a specific aspect of the present invention, in the setting process, the detection unit that previously output the output value corresponding to the absence of the document is set as the first detection unit, and the detection unit that is not the first detection unit is set as the second detection unit. In the conveyance determination process, when the output value corresponding to the absence of the document is acquired from the second detection unit before the output value corresponding to the presence of the document is acquired from the first detection unit, the conveyance unit When it is determined that the document cannot be transported and an output value corresponding to the presence of the document is acquired from the first detection unit, it is determined that the transport unit can transport the document. Therefore, the detection unit that outputs the output value corresponding to the absence of the document is set as the first detection unit, the detection unit that is not the first detection unit is set as the second detection unit, and the first detection unit responds to the presence of the document. When the output value corresponding to the absence of the document is acquired from the second detection unit before the output value to be acquired is determined, the conveyance unit determines that the document cannot be conveyed, and the output value corresponding to the presence of the document from the first detection unit In order to determine whether or not the document can be conveyed by the conveyance unit, the conveyance roller determines whether or not the document can be conveyed by the conveyance roller without performing complicated determination processing such as different determination processing by the plurality of detection units. Judgment can be made.

1 is a diagram illustrating an internal configuration of an image reading apparatus 1 according to an embodiment of the present invention. (A) It is the schematic showing the structure of conveyance path 40 periphery with the arrangement | positioning of each sensor. FIG. 4B is an enlarged view around the ultrasonic sensor UA and the conveyance roller 41. FIG. 2 is a block diagram illustrating an electrical configuration of the image reading apparatus 1. FIG. It is a flowchart which shows a reading main process. 6 is a flowchart illustrating document detection processing. It is a flowchart which shows the conveyance impossibility detection process RA7. It is a flowchart which shows reading process R8. It is a flowchart which shows the re-transport process RC4. It is a flowchart which shows the reading completion process RC6.

<Configuration of Image Reading Apparatus 1>
With reference to FIG. 1 and FIG. 2, the image reading apparatus 1 of this embodiment is demonstrated. In FIG. 1, the transport direction TD is the direction indicated by the arrow. In FIG. 2, the transport direction TD and the main scanning direction MD are directions indicated by arrows. The image reading apparatus 1 of the present embodiment is configured as an auto document feeder type scanner apparatus. The image reading apparatus 1 includes a document tray 10, a main body unit 3, and a paper discharge tray 15. An operation unit 96 and a display unit 95 are disposed on the upper surface of the main body unit 3. The operation unit 96 includes a power switch and various setting buttons, and receives operation commands and the like from the user. For example, the operation unit 96 includes a start button for instructing the start of the reading operation. The display unit 95 includes an LCD (abbreviation for Liquid Crystal Display) and displays the status of the image reading apparatus 1. The document tray 10 is provided with a front sensor FS that can detect the document Q. The front sensor FS is turned on when the document tray 10 supports the document Q, and turned off when the document tray 10 does not support the document Q.

  A conveyance path 40 is formed inside the main body 3. The document Q supported on the document tray 10 is guided along the transport path 40, transported in the transport direction TD, and discharged onto the paper discharge tray 15. Paper feed roller 31, separation pad 32, ultrasonic sensors UA, UB, rear sensor RS, a pair of transport rollers 41, 42, 43, two line sensors 20, 20, a pair of paper discharge rollers 45, 46 and 47 are arranged along the transport path 40. The conveyance rollers 41 and 43 and the conveyance roller 42 are arranged to face each other in a direction orthogonal to the conveyance surface that constitutes the conveyance path 40.

  The paper feed roller 31 cooperates with the separation pad 32 to separate and feed a plurality of documents Q supported by the document tray 10 one by one. The paper feed roller 31 is driven by a feed motor 53 (see FIG. 3). The paper feed roller 31 is provided with a one-way clutch (not shown). The one-way clutch transmits the drive from the feed motor 53 to the feed roller 31 when the feed motor 53 is driven to rotate the feed roller 31, and feeds the paper when the feed motor 53 is not driven. The connection between the roller 31 and the feeding motor 53 is disconnected, and the conveying operation of the document Q by the conveying rollers 41, 42, 43 is not hindered.

  The ultrasonic sensor UA detects whether or not the document Q exists in the main scanning direction MD of the nip area NE formed by the transport roller 41 and the transport roller 42. The ultrasonic sensor UB detects whether or not the document Q exists in the main scanning direction MD of the nip region NE formed by the transport roller 43 and the transport roller 42.

  The rear sensor RS changes from off to on when the front end of the document Q in the transport direction TD of the document Q is located at the position where the rear sensor RS is disposed, and the rear end of the document in the transport direction TD of the document Q at this position. Changes from on to off when is positioned.

  The transport rollers 41 and 43 and the paper discharge rollers 45 and 47 are driven by a transport motor 51 (see FIG. 3) through a transmission mechanism 52 (see FIG. 3). The conveyance rollers 41, 42, and 43 convey the original Q so that the original Q fed from the paper supply roller 31 passes between the two line sensors 20 and 20. The paper discharge rollers 45, 46, 47 convey the original Q that has passed between the two line sensors 20, 20 to the paper discharge tray 15.

  The image reading apparatus 1 according to the present embodiment includes two line sensors 20 facing each other between the conveying rollers 41, 42, 43 and the paper discharge rollers 45, 46, 47, and is configured to be able to read both sides of the document Q. Is done. These line sensors 20 are configured by, for example, a contact image sensor.

  A positional relationship among the transport rollers 41, 42, 43, the discharge rollers 45, 46, 47, the ultrasonic sensors UA, UB, and the rear sensor RS will be described with reference to FIG. The document tray 10 according to the present embodiment is configured as a center alignment type document tray. That is, the document tray 10 is configured so that the user can place a plurality of documents Q of the same size on the document tray 10 with the center of the document Q aligned on the center line LA. In the following description, an A4 size (main scanning direction width 210 mm) original Q is referred to as an original Qa and an A5 size (main scanning direction width 148 mm) original Q is referred to as an original Qb. In the present embodiment, the A5 size document Qb is the smallest standard size document that can be conveyed by the image reading apparatus 1. In the image reading apparatus 1 of the present embodiment, the transport rollers 41 and 43 are arranged at a first distance L1 from both ends of the A5 size document Qb so that the A5 size document Qb is transported without skew. Has been. In the present embodiment, the transport rollers 41 and 43 are disposed symmetrically about the center line LA in the main scanning direction MD.

  As shown in FIG. 2A, ultrasonic sensors UA, UB and a rear sensor RS are provided between the paper feed roller 31 and the transport rollers 41, 42, 43. Specifically, the position in the transport direction TD that is separated from the transport rollers 41, 42, 43 upstream by the second distance L2 along the transport direction TD is the position of the sub-line LD. The image reading apparatus 1 is provided with a rear sensor RS at a position in the vicinity of the center line LA in the main scanning direction MD of the transport path 40 and on the sub line LD in the transport direction TD. The position of the sub line LB is a position that is separated from the side end portion of the original Qb on the upstream side in the main scanning direction MD by the first distance L1 downstream in the main scanning direction MD. The position of the sub-line LC is a position that is separated from the side end portion of the document Qb on the downstream side in the main scanning direction MD by the first distance L1 upstream in the main scanning direction MD. The ultrasonic sensor UA is disposed at the intersection of the sub line LC and the sub line LD. The ultrasonic sensor UB is disposed at the intersection of the sub line LB and the sub line LD. The paper discharge rollers 45, 46, and 47 are disposed at positions separated from the sub line LD along the transport direction TD by a third distance L3.

  The relationship between the detection range DE of each ultrasonic sensor and the nip region NE formed by each transport roller will be described with reference to FIG. For example, the relationship between the detection range DE of the ultrasonic sensor UA and the nip region NE formed by the transport roller 41 and the transport roller 42 will be described with reference to FIG. The distance in the main scanning direction MD of the nip region NE formed by the transport roller 41 and the transport roller 42 is a nip distance NEL. When the output value of the ultrasonic sensor UA is equal to or greater than the threshold value TH, the document Q does not exist in the detection range DE of the ultrasonic sensor UA. The detection range DE of the ultrasonic sensor UA that is equal to or greater than the threshold value TH is a range in which the detection diameter DCD is centered on the ultrasonic sensor UA. The detection diameter DCD is longer than the nip distance NEL. Therefore, the detection range DE in the main scanning direction MD of the ultrasonic sensor UA includes the nip region NE in the main scanning direction MD formed by the transport rollers 41 and 42. The threshold value TH is a value that is set before shipment in each ultrasonic sensor so that the detection range DE has a detection diameter DCD that is longer than the nip distance NEL. Also for the ultrasonic sensor UB, as in the ultrasonic sensor UA, the detection range DE of the ultrasonic sensor UB that is equal to or greater than the threshold value TH is a range that is the detection diameter DCD centered on the ultrasonic sensor UB, and the detection diameter The DCD is longer than the nip distance NEL that is the distance in the main scanning direction MD of the nip area NE formed by the transport roller 43 and the transport roller 42. Therefore, the detection range DE in the main scanning direction MD of the ultrasonic sensor UB includes the nip region NE in the main scanning direction MD formed by the transport rollers 42 and 43. In the present embodiment, the nip distance NEL is “20 mm”. The detection diameter DCD is “25 mm”. When the output values of the ultrasonic sensors UA and UB are equal to or higher than the threshold value TH, it indicates that there is no original, and when the output values of the ultrasonic sensors UA and UB are lower than the threshold value TH, it indicates that there is an original. Show.

<Electrical Configuration of Image Reading Apparatus 1>
The electrical configuration of the image reading apparatus 1 will be described with reference to FIG. 3, the image reading apparatus 1 includes a main unit 60, a reading control unit 70, a motor control unit 80, an AD converter 90, an operation unit 96, a display unit 95, and a communication interface (hereinafter referred to as communication I / F) 99. As a main component.

  The main unit 60 performs overall control of the entire image reading apparatus 1. The main unit 60 includes a CPU 61, a ROM 63, a RAM 65, and an NVRAM 67. The CPU 61 executes a process according to a program stored in the ROM 63. The RAM 65 is used as a work area when the CPU 61 executes processes. The NVRAM 67 is an electrically rewritable nonvolatile memory and stores various data. The main unit 60 performs overall control of the image reading apparatus 1 by executing various processes in the CPU 61. Various flags to be described later are stored in the RAM 65.

  The main unit 60 communicates with the external device 3 via the communication I / F 99, for example. When the main unit 60 receives the reading command by pressing the start button of the operation unit 96, the reading control unit is configured so that the reading operation of the document Q based on the reading command is realized as described later. 70 and the motor control unit 80 are controlled. Thereafter, the main unit 60 operates to provide read image data representing a read image of the original Q generated by the reading operation of the original Q to the external device 3 via the communication I / F 99. The external device 3 is a personal computer, for example, and is provided with read image data from the image reading device 1.

  Based on a command from the main unit 60, the reading control unit 70 performs drive control of the line sensor 20 so that the line sensor 20 performs a reading operation in accordance with the conveying operation of the document Q. The reading control unit 70 sequentially transmits line data that is image data for each line generated by the reading operation of the line sensor 20 to the main unit 60. The main unit 60 generates the read image data representing the read image of the original Q by combining the line data in the read main process described later, and provides the read image data to the external device 3 after the read main process is completed. To do.

  The motor control unit 80 realizes transport control of the document Q from the document tray 10 to the transport rollers 41, 42, and 43 by performing drive control of the feeding motor 53 based on a command from the main unit 60. The motor control unit 80 implements transport control of the document Q from the transport rollers 41, 42, 43 to the paper discharge tray 15 by performing drive control of the transport motor 51 based on a command from the main unit 60. The conveyance motor 51 and the feeding motor 53 are configured by, for example, stepping motors. In this case, the motor control unit 80 can control the conveyance amount of the document Q by controlling the rotation amount of the conveyance motor 51 or the feeding motor 53. In the present embodiment, as will be described later, when the document Q cannot be transported by the transport rollers 41, 42, 43, the motor control unit 80 drives the feed motor 53 based on a command from the main unit 60. In addition, the conveyance operation from the arrangement position of the conveyance rollers 41, 42, 43 to the arrangement position of the paper discharge rollers 45, 46, 47 is realized.

  The AD converter 90 is configured to convert the output values of the front sensor FS, the rear sensor RS, and the ultrasonic sensors UA, UB into digital values and input the digital values to the main unit 60. The operation unit 96 is configured to input a signal corresponding to an operation input by the user to the main unit 60. The display unit 95 receives a signal sent from the main unit 60 and displays the status of the apparatus.

<Operation of Image Reading Apparatus 1>
(Reading main process)
Next, the operation of the image reading apparatus 1 will be described with reference to the drawings. The image reading apparatus 1 mainly executes a reading main process for reading the document Q and a document detection process. Processes R1 to R8 during the main reading process shown in FIG. 4 are processes executed by the main unit 60, and processes RA1 to RA10 during the document detection process shown in FIG. 5 are processes executed by the main unit 60. is there.

  The reading main process shown in FIG. 4 is started when the user places the document Q on the document tray 10 and presses the start button of the operation unit 96. That is, when the front unit FS is turned on and the main unit 60 receives a reading command by pressing the start button of the operation unit 96, the main unit 60 starts the reading main process.

  The main unit 60 initializes the reading control unit 70, the motor control unit 80, etc. (R1). Specifically, the main unit 60 sets setting values necessary for executing the reading process in the reading control unit 70 and the motor control unit 80. The main unit 60 turns off the continuation flag CNFG, turns off the transport flag CVFG, and deletes the set value of the rear flag RFG. Here, when the set value is deleted, the rear flag RFG becomes a value that is neither off nor on.

  The main unit 60 transmits a command to the motor control unit 80, drives the feeding motor 53, and starts a feeding operation for transporting the document Q in the transport direction TD (R2).

  The main unit 60 determines whether or not the rear sensor RS has changed from off to on (R3). The main unit 60 proceeds to processing R4 when the rear sensor RS changes from off to on (R3: Yes), and supplies the document Q when the rear sensor RS does not change from off to on (R3: No). Continue feeding operation.

  The main unit 60 starts the detection operation of the ultrasonic sensors UA and UB (R4). In this embodiment, the detection time interval of each ultrasonic sensor is “5 ms”. In the present embodiment, this detection operation is repeatedly executed until the document detection process is completed.

  The main unit 60 drives the transport motor 51 (R5). Specifically, the main unit 60 transmits a command to the motor control unit 80 to drive the transport motor 51, and the document Q from the position of the transport rollers 41, 42, 43 in the transport direction TD to the position of the paper discharge tray 15. The transport operation for transporting is started.

  The main unit 60 sets the rotation amount of the feeding motor 53 (R6). Specifically, the main unit 60 transmits a command to the motor control unit 80, and rotates the feeding motor 53 that is being driven by a rotation amount corresponding to the second distance L2 from the time when it is determined Yes in the process R3. Then, the feeding motor 53 is rotated.

  The main unit 60 starts the document detection process (R7). The main unit 60 executes document detection processing in parallel with the reading main processing. The document detection process will be described later and will be outlined here. In the document detection process, the main unit 60 stores the rear flag RFG or the transport flag CVFG in the RAM 65.

  The main unit 60 executes a reading process (R8). Details will be described later and will be outlined here. The main unit 60 executes a re-transport process RC4 described later when the transport flag CVFG is on, and the document leading edge in the transport direction TD of the document Q when the rear flag RFG is on or off. A reading operation for reading from the document to the trailing edge of the document is executed. When the process R8 ends, the reading main process ends.

(Document detection processing)
When the process R7 during the reading main process is executed, the document detection process shown in FIG. 5 is started. The main unit 60 determines whether or not the output value of the ultrasonic sensor UA is greater than or equal to the threshold value TH (RA1). When the output value of the ultrasonic sensor UA is greater than or equal to the threshold value TH (RA1: Yes), the main unit 60 proceeds to processing RA5, and when the output value of the ultrasonic sensor UA is less than the threshold value TH (RA1: No). Then, the process proceeds to process RA2.

  The main unit 60 determines whether or not the output value of the ultrasonic sensor UB is greater than or equal to the threshold value TH (RA2). When the output value of the ultrasonic sensor UB is greater than or equal to the threshold value TH (RA2: Yes), the main unit 60 proceeds to processing RA6, and when the output value of the ultrasonic sensor UB is less than the threshold value TH (RA2: No). Then, the process proceeds to process RA3.

  The main unit 60 determines whether or not the document Q has been conveyed by the third distance L3 from the time when it is determined Yes in the process R3 (RA3). Specifically, the main unit 60 determines whether or not the transport motor 51 has been driven by the amount of rotation corresponding to the third distance L3 from the time when it is determined Yes in the process R3. When the main unit 60 drives the transport motor 51 by the rotation amount corresponding to the third distance L3 (RA3: Yes), the main unit 60 proceeds to processing RA9 and drives the transport motor 51 by the rotation amount corresponding to the third distance L3. If not (RA3: No), the process proceeds to process RA4.

  The main unit 60 determines whether or not the rear sensor RS has changed from on to off (RA4). The main unit 60 proceeds to process RA10 when the rear sensor RS changes from on to off (RA4: Yes), and proceeds to process RA1 when the rear sensor RS does not change from on to off (RA4: No). . In the present embodiment, the processes from the process RA1 to the process RA4 are processes that are repeatedly executed until the result of each process becomes Yes. While the processes from the process RA1 to the process RA4 are repeatedly executed, the process RA1, the output values of all the ultrasonic sensors output at “5 ms”, which is the detection time interval of each ultrasonic sensor, Then, the process RA2 is executed.

  If it is determined Yes in process RA1, the main unit 60 sets the ultrasonic sensor UA as the detection sensor DS and sets the ultrasonic sensor UB as the non-detection sensor NDS (RA5). When the process RA5 ends, the main unit 60 proceeds to the process RA7.

  If it is determined Yes in process RA2, the main unit 60 sets the ultrasonic sensor UB as the detection sensor DS and sets the ultrasonic sensor UA as the non-detection sensor NDS (RA6).

  The main unit 60 performs a conveyance impossibility detection process (RA7). Details will be described later and will be outlined here. The main unit 60 turns on the continuation flag CNFG, turns on the transport flag CVFG, or turns on the rear flag RFG and stores it in the RAM 65.

  The main unit 60 determines whether or not the continuation flag CNFG is on (RA8). When the continuation flag CNFG is on (RA8: Yes), the main unit 60 proceeds to process RA1, and when the continuation flag CNFG is off (RA8: No), the document detection process ends.

  If it is determined Yes in process RA3, the main unit 60 turns off the rear flag RFG and stores it in the RAM 65 (RA9). When the process RA9 ends, the document detection process ends.

  If it is determined Yes in process RA4, the main unit 60 turns on the rear flag RFG and stores it in the RAM 65 (RA10). When the process RA10 ends, the document detection process ends.

(Conveyance impossible detection process RA7)
When the conveyance failure detection process RA7 shown in FIG. 6 is started, the main unit 60 determines whether or not the output value of the detection sensor DS is equal to or greater than the threshold value TH (RB1). When the output value of the detection sensor DS is greater than or equal to the threshold value TH (RB1: Yes), the main unit 60 proceeds to processing RB2, and when the output value of the detection sensor DS is less than the threshold value TH (RB1: No), The process proceeds to process RB4.

  The main unit 60 determines whether or not the output value of the non-detection sensor NDS is greater than or equal to the threshold value TH (RB2). When the output value of the non-detection sensor NDS is greater than or equal to the threshold value TH (RB2: Yes), the main unit 60 proceeds to processing RB5, and when the output value of the non-detection sensor NDS is less than the threshold value TH (RB2: No) Then, the process proceeds to process RB3. In the present embodiment, “Yes” in the process RB2 means that all the ultrasonic sensors UA and UB are determined to be equal to or greater than the threshold value TH.

  The main unit 60 determines whether or not the rear sensor RS has changed from on to off (RB3). The main unit 60 proceeds to process RB6 when the rear sensor RS changes from on to off (RB3: Yes), and proceeds to process RB1 when the rear sensor RS does not change from on to off (RB3: No). . In the present embodiment, the processes from the process RB1 to the process RB3 are repeatedly executed while it is determined Yes in the process RB1, No is determined in the process RB2, and No is determined in the process RB3. While the processes from the process RB1 to the process RB3 are repeatedly executed, the process RB1, the output values of all the ultrasonic sensors output at “5 ms” that is the detection time interval of each ultrasonic sensor, Then, process RB2 is executed.

  If it is determined No in process RB1, the main unit 60 turns on the continuation flag CNFG and stores it in the RAM 65 (RB4). When the process RB4 is completed, the conveyance failure detection process RA7 is completed.

  If it is determined Yes in process RB2, the main unit 60 turns on the transport flag CVFG and stores it in the RAM 65 (RB5). When the process RB5 is completed, the conveyance failure detection process RA7 is completed.

  If it is determined Yes in process RB3, the main unit 60 turns on the rear flag RFG and stores it in the RAM 65 (RB6). When the process RB6 is finished, the conveyance impossibility detection process RA7 is finished.

(Reading process R8)
When the reading process R8 shown in FIG. 7 is started, the main unit 60 transmits a command to the reading control unit 70, and is conveyed to a position where the leading end of the document Q in the conveyance direction TD of the document Q faces the reading unit 20. From time to time, the reading operation for reading the document Q is started (RC1).

  The main unit 60 determines whether or not the transport flag CVFG is on (RC2). The main unit 60 proceeds to process RC4 when the transport flag CVFG is on (RC2: Yes), and proceeds to process RC3 when the transport flag CVFG is not on (RC2: No).

  The main unit 60 determines whether or not the document detection process is completed (RC3). Specifically, when the rear flag RFG is on or the rear flag RFG is off (RC3: Yes), the main unit 60 determines that the document detection process has ended, and proceeds to process RC6. When the rear flag RFG is neither on nor off (RC3: No), the main unit 60 determines that the document detection process has not ended, and proceeds to process RC2. In the present embodiment, when the rear flag RFG is on, the rear end of the document in the transport direction TD of the document Q is positioned at the position of the rear sensor RS in the transport direction TD, and when the rear flag RFG is off, the document The leading edge of the document in the Q transport direction TD is located at the position of the paper discharge rollers 45, 46, 47 in the transport direction TD.

  If it is determined Yes in the process RC2, the main unit 60 executes a re-transport process (RC4). Details will be described later and will be outlined here. The main unit 60 transmits a command to the motor control unit 80, drives the feeding motor 53, and conveys the document Q. The main unit 60 stores the conveyance stop flag CSFG in the RAM 65 as on or off.

  The main unit 60 determines whether or not the transport stop flag CSFG is on (RC5). The main unit 60 proceeds to process RC6 when the transport stop flag CSFG is on (RC5: Yes), and proceeds to process RC2 when the transport stop flag CSFG is off (RC5: No).

  When it is determined Yes in the process RC3 or Yes in the process RC5, the main unit 60 executes a reading end process (RC6). Details will be described later and will be outlined here. When the transport stop flag CSFG is on, the main unit 60 transmits a command to the motor control unit 80, stops the transport operation by the transport motor 51 and the feed motor 53, and the transport operation of the document Q is abnormal. Is displayed on the display unit 95. When the conveyance stop flag CSFG is off, the main unit 60 performs a reading operation for reading up to the rear end portion of the document in the conveyance direction TD of the document Q. When the process RC6 ends, the reading process R8 ends.

(Re-transfer process RC4)
When the re-conveying process RC4 shown in FIG. 8 is started, the main unit 60 sets the document leading edge in the conveyance direction TD of the document Q to the position of the discharge rollers 45, 46, 47 in the conveyance direction TD. The feeding motor 53 is driven (RD1). Specifically, the main unit 60 transmits a command to the motor control unit 80, and turns the feeding motor 53 by a rotation amount corresponding to the conveyance amount to the position of the paper discharge rollers 45, 46, 47 in the conveyance direction TD. Drive. The transport amount to the position of the paper discharge rollers 45, 46, 47 in the transport direction TD is the third transport amount driven by the transport motor 51 from the time when it is determined Yes in the process R3 to the time when the process RD is executed. It is calculated by subtracting from the distance L3.

  The main unit 60 determines whether or not the document Q has been conveyed by the third distance L3 from the time when it is determined Yes in the process R3 (RD2). Specifically, the main unit 60 determines whether or not the feeding motor 53 has been driven by the amount of rotation corresponding to the third distance L3 from the time when it is determined Yes in the process R3. When the main unit 60 drives the feed motor 53 by the rotation amount corresponding to the third distance L3 (RD2: Yes), the main unit 60 proceeds to process RD4, and advances the feed motor 53 by the rotation amount corresponding to the third distance L3. Is not driven (RD2: No), the process proceeds to process RD3.

  The main unit 60 determines whether or not the output values of the ultrasonic sensors UA and UB are both greater than or equal to the threshold value TH (RD3). When the output values of the ultrasonic sensors UA and UB are both equal to or higher than the threshold value TH (RD3: Yes), the main unit 60 proceeds to processing RD2, and any one of the ultrasonic sensors UA and UB is less than the threshold value TH. (RD3: No), the process proceeds to process RD5. In this embodiment, while it is determined No in the process RD2 and Yes is determined in the process RD3, the processes from the process RD2 to the process RD3 are repeatedly executed. While the processes from the process RD2 to the process RD3 are repeatedly executed, the process RD2 is performed on the output values of all the ultrasonic sensors output at “5 ms” that is the detection time interval of each ultrasonic sensor. Executed.

  When it is determined Yes in process RD2, the main unit 60 turns on the conveyance stop flag CSFG and stores it in the RAM 65 (RD4). When the process RD4 ends, the re-transport process RC4 ends. In the present embodiment, when the conveyance stop flag CSFG is on, the feeding motor 53 is set such that the leading edge of the original Q in the conveyance direction TD of the original Q is positioned at the paper discharge rollers 45, 46, 47 in the conveyance direction TD. Even when is driven, the output values of the ultrasonic sensors UA and UB are both equal to or higher than the threshold value TH. In such a case, the document Q cannot be transported inside the transport path 40.

  If it is determined No in the process RD3, the main unit 60 turns off the conveyance stop flag CSFG and stores it in the RAM 65 (RD5). When the process RD5 ends, the re-transport process RC4 ends.

(Reading end process RC6)
When the reading end process RC6 shown in FIG. 9 is started, the main unit 60 determines whether or not the transport stop flag CSFG is on (RE1). The main unit 60 proceeds to process RE6 when the transport stop flag CSFG is on (RE1: Yes), and proceeds to process RE2 when the transport stop flag CSFG is off (RE1: No).

  The main unit 60 determines whether or not the rear flag RFG is on (RE2). The main unit 60 proceeds to process RE5 when the rear flag RFG is on (RE2: Yes), and proceeds to process RE3 when the rear flag RFG is off (RE2: No).

  The main unit 60 determines whether or not the rear sensor RS has changed from on to off (RE3). The main unit 60 proceeds to processing RE4 when the rear sensor RS changes from on to off (RE3: Yes), and reads the document Q when the rear sensor RS does not change from on to off (RE3: No). Continue operation.

  The main unit 60 turns on the rear flag RFG and stores it in the RAM 65 (RE4).

  The main unit 60 ends the reading operation of the document Q at a position where the rear end portion of the document in the transport direction TD of the document Q faces the reading unit 20 (RE5). When the process RE5 ends, the reading end process RC6 ends.

  If it is determined Yes in process RE1, the main unit 60 transmits a command to the motor control unit 80, and stops the transport operation of the document Q by the transport motor 51 and the feed motor 53 (RE6).

  The main unit 60 displays on the display unit 95 that the conveyance operation of the original Q is abnormal (RE7). By checking the display unit 95, the user can know that the conveyance operation of the document Q is abnormal, and can remove the document Q from the image reading apparatus 1 as necessary.

<Effect of embodiment>
In the present embodiment, in the conveyance failure detection process RA7, the process RB1 proceeds to the process RB2 when the output value of the detection sensor DS is equal to or greater than the threshold value TH. The process RB2 proceeds to the process RB5 when the output value of the non-detection sensor NDS is greater than or equal to the threshold value TH. The process RB5 turns on the transport flag CVFG and stores it in the RAM 65. In the reading process R8, the process RC2 proceeds to process RC4 when the transport flag CVFG is on. In process RC4, process RD1 drives the feed motor 53 so that the leading edge of the document Q in the transport direction TD is positioned at the discharge rollers 45, 46, 47 in the transport direction TD. Therefore, by determining whether the output values of the detection sensor DS and the non-detection sensor NDS are both greater than or equal to the threshold value TH, it is determined whether the document cannot be transported by the transport rollers 45, 46, and 47. Even when the document cannot be transported by the transport rollers 45, 46, 47, the document Q can be transported by driving the feeding motor 53.

  In the present embodiment, in the re-conveying process RC4, the process RD3 proceeds to the process RD2 when the output values of the ultrasonic sensors UA and UB are both equal to or greater than the threshold value TH. The process RD2 proceeds to the process RD4 when the feeding motor 53 is driven by the amount of rotation corresponding to the third distance L3 from the time point determined as Yes in the process R3. The process RD4 turns on the conveyance stop flag CSFG and stores it in the RAM 65. In the reading end process RC6, the process RE1 proceeds to the process RE6 when the transport stop flag CSFG is on. In the process RE6, the conveyance operation of the document Q by the conveyance motor 51 and the feeding motor 53 is stopped. The process RE7 displays on the display unit 95 that the conveyance operation of the original Q is abnormal. Therefore, when the conveyance motor 53 is rotated by the rotation amount corresponding to the third distance L3 and the output values of the ultrasonic sensors UA and UB are both equal to or greater than the threshold value TH, the conveyance operation of the original Q is stopped and the conveyance operation is stopped. When the document Q cannot be transported by the feeding motor 53, the transport operation of the document Q can be stopped and the user can be notified of the transport error of the document Q. it can.

  In the present embodiment, in the document detection process, the process RA1 proceeds to the process RA5 when the output value of the ultrasonic sensor UA is equal to or greater than the threshold value TH. Process RA5 sets the ultrasonic sensor UA as the detection sensor DS and sets the ultrasonic sensor UB as the non-detection sensor NDS. The process RA2 proceeds to the process RA6 when the output value of the ultrasonic sensor UB is equal to or greater than the threshold value TH. Process RA6 sets the ultrasonic sensor UB as the detection sensor DS and sets the ultrasonic sensor UA as the non-detection sensor NDS. The process RB2 proceeds to the process RB5 when the output value of the non-detection sensor NDS is greater than or equal to the threshold value TH. The process RB5 turns on the transport flag CVFG and stores it in the RAM 65. Therefore, the ultrasonic sensor previously determined to be equal to or higher than the threshold TH is set as the detection sensor DS, the ultrasonic sensor determined to be not higher than the threshold TH is set as the non-detection sensor NDS, and the output value of the non-detection sensor NDS is Since the conveyance flag CVFG is turned on when the threshold value TH is equal to or higher than the threshold value TH, the conveyance rollers 45, 46, and so on are performed without performing complicated determination processing such as different determination processing between the ultrasonic sensor UA and the ultrasonic sensor UB. 47, it can be determined whether or not the original Q can be conveyed.

[Correspondence between embodiment and invention]
The image reading device 1, the paper discharge tray 15, and the document tray 10 are examples of the image reading device, the paper discharge tray, and the document tray of the present invention. The paper feed roller 31 is an example of the separation roller of the present invention. The paper feed roller 31, the separation pad 32, the feed motor 53, and the motor control unit 80 are examples of the separation unit of the present invention. The conveyance rollers 41, 42, 43, the transmission mechanism 52, the conveyance motor 51, and the motor control unit 80 are examples of the conveyance unit of the present invention. The paper discharge rollers 45, 46, 47, the transmission mechanism 52, the transport motor 51, and the motor control unit 80 are examples of the paper discharge unit of the present invention. The ultrasonic sensors UA and UB are an example of the detection unit of the present invention. The main unit 60 and the display unit 95 are examples of the control unit and the display unit of the present invention.

  Process R4 is an example of the acquisition process of the present invention. Process RB1 and process RB2 are examples of the conveyance determination process of the present invention. Process RD1 is an example of the re-transport process of the present invention. Process RD2, process RD4, process RE1, and process RE6 are examples of the stop process of the present invention. The process RE7 is an example of the display process of the present invention. Process RA3 and process RA4 are examples of the end process of the present invention. Process RA5 and process RA6 are examples of the setting process of the present invention.

[Modification]
The present invention is not limited to this embodiment, and various modifications can be made without departing from the spirit of the present invention. An example of the modification will be described below.

  (1) The image reading apparatus 1 according to the present embodiment may be applied to a multi-function machine including a printer unit. In the present embodiment, the case where the line sensor 20 is configured by a contact image sensor has been described. However, the line sensor 20 may be configured by a reduction optical image sensor.

  (2) In the present embodiment, the number of the transport rollers 41, 42, and 43 and the number of the ultrasonic sensors UA and UB have been described as being two, but different numbers may be used. Any number of transport rollers may be provided as long as the feed roller 31 is located at a position other than the center. In that case, the same number of ultrasonic sensors as the transport rollers are arranged at the positions of the transport rollers in the main scanning direction MD.

  (3) In the present embodiment, the detection range DE of the ultrasonic sensor in the main scanning direction MD has been described as including the nip region NE of the transport roller, but may be a different range. For example, the size of the detection range of the ultrasonic sensor in the transport direction TD and the main scanning direction MD may be larger than the size of the transport roller in the transport direction TD and the main scanning direction MD.

  (4) In the present embodiment, it has been described that when the output values of the ultrasonic sensors UA and UB are equal to or greater than the threshold value TH, there is no document Q on the conveyance roller corresponding to each ultrasonic sensor. good. It may be detected that the original Q is not present on the conveying roller by irradiating the original Q with light having high directivity and detecting the presence or absence of transmitted light or the presence of reflected light by an optical sensor.

DESCRIPTION OF SYMBOLS 1 ... Image reading apparatus, 3 ... External device, 10 ... Document tray, 15 ... Paper discharge tray, 20 ... Line sensor, 31 ... Paper feed roller, 32 ... Separation pad, 40 ... Conveyance path, 41, 42, 43 ... Conveyance Roller, 45, 46, 47 ... paper discharge roller, 51 ... transport motor, 52 ... transmission mechanism, 53 ... feed motor, 60 ... main unit, 61 ... CPU, 63 ... ROM, 65 ... RAM, 67 ... NVRAM, 70 ... Reading control unit, 80 ... Motor control unit, 90 ... AD converter, 95 ... Display unit, 96 ... Operating unit, 99 ... Communication I / F, FS ... Front sensor, RS ... Rear sensor, UA, UB ... Ultrasonic sensor LA ... center line, LB, LC, LD ... sub-line, Q ... document, DE ... detection range, NE ... nip area, R8 ... reading process, RA7 ... conveyance failure detection process, RC4 ... re-carrying process, RC6 ... Exit processing preparative

Claims (6)

A document tray that supports the document,
A reading unit that reads an image of a document along the main scanning direction;
A separation unit that includes a separation roller disposed at a center position of the document tray in the main scanning direction, and separates the documents supported by the document tray one by one;
A plurality of conveying rollers arranged symmetrically with respect to the central position in the main scanning direction, the document separated by the separation unit being orthogonal to the main scanning direction and the document being conveyed from the document tray to the reading unit; A transport unit that transports the reading unit along the transport direction,
Arranged at a plurality of roller positions, which are positions of the plurality of transport rollers in the main scanning direction, and disposed upstream of the position of the transport roller in the transport direction, and outputs an output value corresponding to the presence or absence of a document. A plurality of detectors;
A control unit,
The controller is
An acquisition process of acquiring a plurality of output values at the plurality of roller positions from the plurality of detection units, respectively.
A conveyance determination process for determining whether or not the conveyance unit can convey the document separated by the separation unit based on the plurality of output values;
A re-conveying process for performing a re-conveying operation for conveying the original separated by the separating unit to the separating unit when the conveying unit determines that the original separated by the separating unit cannot be conveyed. An image reading apparatus. Each detection unit of the plurality of detection units outputs an output value corresponding to the presence or absence of a document in a predetermined range centered on each roller position where each detection unit is arranged in the main scanning direction,
The conveyance determination process includes
Including a document no determination process for determining whether or not all of the plurality of output values are output values corresponding to no document,
When the plurality of output values are all output values corresponding to no document, the conveyance unit determines that the document separated by the separation unit cannot be conveyed,
When any one of the plurality of output values is an output value corresponding to presence of a document, it is determined that the transport unit can transport the document separated by the separation unit;
The transport roller is composed of a pair of transport rollers arranged to face each other in a direction orthogonal to a transport surface that constitutes a transport path that guides a document separated by the separation unit,
The image reading apparatus according to claim 1, wherein the predetermined range includes a nip region formed in the pair of transport rollers in a main scanning direction. A paper discharge tray that supports the document read by the reading unit;
A paper discharge unit that includes a paper discharge roller disposed at a position downstream of the reading unit in the transport direction, and that transports a document read by the reading unit to the paper discharge tray;
A display unit,
The acquisition process acquires the plurality of output values from the plurality of detection units at predetermined time intervals, respectively.
The controller is
Corresponds to the transport amount in which the leading edge in the transport direction of the document transported by the separation unit is transported to the position of the paper discharge roller in the transport direction from when the document is transported by the separation unit in the re-conveying process. Stop processing for stopping the re-conveying operation when the plurality of output values acquired at the predetermined time interval are all output values corresponding to the absence of a document until the separation roller is rotated by a rotation amount; ,
3. The image reading according to claim 1, wherein when the re-conveying operation is stopped, display processing for displaying display data indicating an abnormality in conveying the document on the display unit is executed. apparatus. The controller is
When the leading end in the transport direction of the document separated by the separation unit rotates the transport roller by a rotation amount corresponding to the transport amount transported to the position of the paper discharge roller in the transport direction, the transport determination process The image reading apparatus according to claim 3, wherein an end process for ending is executed. A document end detection unit that is disposed at the position of the detection unit in the transport direction and that is disposed at the center position in the main scanning direction and detects a rear end portion of the document separated by the separation unit in the transport direction;
The image reading apparatus according to claim 4, wherein the end process ends the conveyance determination process when the document end detection unit detects a trailing end of the document. The number of the plurality of detection units is two,
The number of the plurality of transport rollers is two,
The controller is
Among the plurality of detection units, a detection unit that first outputs an output value corresponding to no document is set as a first detection unit, and among the plurality of detection units, a detection unit that is not the first detection unit is set as a second detection unit. Execute the setting process to set in the detector,
The conveyance determination process includes
It is executed after executing the setting process,
A document in which the transport unit is separated by the separation unit when an output value corresponding to no document is obtained from the second detection unit before obtaining an output value corresponding to presence of the document from the first detection unit. It ca n’t be transported,
6. The apparatus according to claim 1, wherein when the output value corresponding to presence of a document is acquired from the first detection unit, the transport unit determines that the document separated by the separation unit can be transported. The image reading apparatus according to any one of the above.

Images