JP6164137B2 - Reader - Google Patents

Description

  The present invention relates to a technique for detecting whether a document is being jammed during conveyance.

  2. Description of the Related Art Conventionally, there is a recording paper conveyance device that conveys recording paper by various rollers (see Patent Document 1). This recording paper transport device has a plurality of recording paper detection means in the recording paper transport path, and the time from detection of the leading edge of the recording paper detected by the plurality of recording paper detection means to detection of the trailing edge A paper jam is detected.

Japanese Patent Laid-Open No. 9-226983

  In a reading apparatus that conveys a document using the conventional configuration described above and reads the document, a reading unit that reads the document is arranged at a position different from the plurality of recording paper detection units on the document conveyance path. For this reason, in the conventional configuration described above, even if it is possible to detect whether or not the document is jammed at the detection position where the recording paper detection unit is arranged on the conveyance path, whether or not the document is jammed at the reading position where the reading unit is arranged Could not be detected.

  The present specification discloses a technique capable of detecting the presence or absence of a document jam at a reading position.

  The reading device disclosed in this specification includes a conveyance unit, a reading unit, and a control unit, and the control unit reads according to an image of a document that is conveyed by the conveyance unit and passes through a reading position. A reading process for causing the reading unit to perform an output operation for outputting data, a plain color determination process for determining whether or not the read data output by the reading unit is plain data, and plain data in the plain color determination process And a jam determination process for determining whether or not the document is jammed based on the read data determined to be.

  In this reading apparatus, the reading unit outputs read data corresponding to the image of the document passing through the reading position, and the control unit determines whether the document is clogged based on the read data output by the reading unit. Thereby, it is possible to detect whether or not the document is jammed at the reading position. Further, when detecting whether or not the document is jammed at the reading position, the read data determined not to be plain data, that is, the read data determined to be plain data by using the read data including characters and drawings, That is, it is possible to accurately determine whether or not a document is clogged from changes in characters and drawings as compared with the case of using read data that does not include characters and drawings.

  In the reading apparatus, the reading unit performs an output operation each time an image of a document is read in the main scanning direction using a plurality of reading elements arranged in the main scanning direction, and the control unit determines the plain color determination. In the processing, the line read data is converted in response to a difference in density between an image density of line read data that is read data output by one output operation of the reading unit and a reference density being less than a first threshold value. It may be determined as plain data, and the line read data may be determined as not plain data in response to the density difference being equal to or greater than the first threshold value.

  In this reading apparatus, since it is determined whether or not the line reading data is plain data based on the density difference between the image density of the line reading data and the reference density, it is determined whether or not the line reading data is plain data. It's easy to do.

  In the reading apparatus, the control unit may execute an acquisition process of acquiring the image density of the front line read data corresponding to the image of the front edge of the document as the reference density. In this reading apparatus, a reference density is set from leading edge line reading data output using the leading edge of a document. Accordingly, it is possible to set a reference density according to the original, and it is possible to shorten the time from the start of reading data output to the determination of the presence or absence of the original.

  In the reading device, in the jam determination process, the control unit includes one line reading data and line reading data read next to the one line reading data within a specified range in the main scanning direction. It may be determined that a document jam has occurred when a reading element whose image density difference is equal to or less than the second threshold satisfies a specified condition of a specified ratio or more. .

  In this reading apparatus, the control unit determines the occurrence of the document jam in response to the change in the line read data read continuously satisfying the specified condition, and therefore can determine the occurrence of the document jam. .

  In the above-described reading device, the reading unit includes a first reading unit that outputs first reading data corresponding to an image on the surface of the document that passes through the first reading position, and a document that passes through the second reading position. A second reading unit that outputs second reading data corresponding to the image on the back surface, and the control unit causes the first reading unit and the second reading unit to perform an output operation in the reading process. In the jam determination process, it may be determined whether the document is jammed based on the first read data and the second read data.

  In this reading apparatus, whether or not the document is jammed is determined based on the first read data and the second read data. Compared to the case where the document jam is determined based on any one of the read data, It is possible to accurately determine whether a document is jammed.

  In the reading apparatus, the control unit determines in the jam determination process that a document jam has occurred based on the first read data, and the document jam based on the second read data. When it is determined that the document is jammed, it is determined that the document is jammed. Based on at least one of the read data, it is determined that the document is not jammed. It may be determined that the document is not jammed.

  In this reading apparatus, since it is determined that a document jam has occurred in both the read data of the first read data and the second read data, it is determined that a document jam has occurred. The occurrence of clogging can be accurately determined.

  In the reading device, the control unit executes enhancement processing for generating enhancement data that emphasizes a change in image density from the read data output from the reading unit, and the control unit performs the clogging determination processing. In response to determining that one read data is not plain data and the other read data is plain data, whether one document is jammed based on the read data. The other reading data may be determined based on the enhancement data generated by the enhancement process to determine whether the document is jammed.

  In this reading apparatus, even when no character or figure is included in the position corresponding to each reading unit on both sides of the document, it is determined whether or not the document is jammed based on the first read data and the second read data. be able to.

  The reading apparatus includes a receiving unit, and the control unit executes a receiving process for receiving a reading surface designation from the receiving unit. In the reading process, the single-sided reading designation and the double-sided reading instruction are performed in the receiving process. In response to the reception, the first reading unit and the second reading unit perform an output operation. In the jam determination process, the single-sided reading designation and the double-sided reading instruction are received in the receiving process. The presence or absence of a document jam may be determined based on the first read data and the second read data.

  In this reading apparatus, whether or not the document is jammed is determined based on the first reading data and the second reading data in response to receiving the single-side reading instruction as well as the double-side reading instruction in the receiving process. . Thereby, even in the case of single-sided reading, it is possible to accurately determine whether or not a document is jammed based on the first reading data and the second reading data.

  The reading apparatus includes a receiving unit, and the first reading position and the second reading position are separated from each other by a predetermined distance along a conveyance path along which the document is conveyed by the conveyance unit, Performs a reception process for receiving a document size from the reception unit. In the jam determination process, the reception process simultaneously reads a document size having a length in the sub-scanning direction that is equal to or greater than the specified distance in the reception process. Whether the document is jammed is determined based on the first read data and the second read data, and the size of the document in the sub-scanning direction is less than the specified distance in the receiving process. Whether or not the document is jammed may be determined based on the first read data and the second read data.

  In this reading apparatus, when the length of the document in the sub-scanning direction is equal to or longer than the specified distance and both sides of the document can be read simultaneously using the first reading unit and the second reading unit, the first read at the same time. Based on the read data and the second read data, it is possible to accurately determine whether or not the document is jammed. If the length of the document in the sub-scanning direction is less than the specified distance and both sides of the document cannot be read at the same time using the first reading unit and the second reading unit, the first reading is performed separately. Based on the data and the second read data, it is possible to determine whether or not the document is jammed.

  In the above-described reading apparatus, the control unit may determine whether or not the document is jammed each time line reading data is output. In this reading apparatus, the control unit determines whether or not a document is jammed each time line reading data is output from the reading unit. Accordingly, it is possible to reduce the time until the determination of the document jam is made compared to the case where the document jam is determined after the entire read data is output.

  In the reading apparatus, the control unit repeats the determination every time the line reading data is output in the clogging determination process, and the line reading data satisfying the specified condition continues more than a specified number in the sub-scanning direction. Accordingly, it may be determined that the document is jammed.

  In this reading apparatus, the control unit determines the occurrence of the document jam in response to the line reading data satisfying the specified condition being continued in the sub-scanning direction for the specified number or more, and therefore erroneously determines the document jam. Can be suppressed.

  In the reading apparatus, the control unit determines that the document is conveyed at the first speed by the conveyance unit in the reading process, and that the document is clogged in the jam determination process. Accordingly, the document may be transported to the transport unit at a second speed that is slower than the first speed.

  In this reading apparatus, the conveyance speed of the conveyance unit is decreased from the first speed to the second speed in response to determining that the document is jammed. As a result, a document that cannot be transported at the first speed and is jammed can be transported at the second speed.

  In the reading apparatus, the control unit determines that the document is conveyed at the second speed by the conveyance unit in the reading process, and that the document is not jammed in the jam determination process. Accordingly, the document may be transported to the transport unit at a first speed.

  In this reading apparatus, when the conveyance speed of the conveyance unit is lowered to the second speed due to the jam of the document, the conveyance of the conveyance unit is determined according to the determination that the document is not jammed. Return the speed to the first speed. Thereby, compared with the case where the state where the conveyance speed is lowered continues, the reading time of the original can be shortened.

  With the reading device disclosed in this specification, it is possible to detect the presence or absence of a document jam at the reading position.

Schematic sectional view of the reader Block diagram schematically showing the electrical configuration of the reader Flowchart showing document reading process Flowchart showing first transport reading process Flow chart showing single-sided reading process Flow chart showing the first determination process Flow chart showing clogging judgment processing Flow chart showing duplex reading process Flow chart showing second determination process Flow chart showing second transport reading process The figure which shows the reading data of the original of a double-sided reading instruction The figure which shows the reading data of the original of a single side (front side) reading instruction | indication

<Embodiment>
One embodiment will be described with reference to FIGS. The reading device 1 has at least a scanner function and is an example of a reading device. In the following description, the right side of FIG. 1 is the front side F of the reading device 1, the back side of the paper is the right side R of the reading device 1, and the upper side of the paper is the upper side U of the reading device 1.

1. Mechanical Configuration of Reading Device As shown in FIG. 1, the reading device 1 includes a reading unit 30 and the like in the main body 2, and a reading mechanism 3 for reading the original G above the main body 2. The reading mechanism 3 includes an automatic document feeder (hereinafter referred to as ADF) 40, a reading unit 60, and the like. The reading unit 30 is an example of a first reading unit, and the reading unit 60 is an example of a second reading unit.

  The ADF 40 includes an ADF cover 41, a document tray 42, pressing members 43 and 44, various rollers 46, a paper discharge tray 47, a front sensor (hereinafter referred to as F sensor) 13, a second rear sensor (hereinafter referred to as R2 sensor) 14, and a first rear sensor. (Hereinafter referred to as R1 sensor) 15, a third platen glass 55 made of a transparent glass plate, and the like.

  The ADF 40 is provided with a transport path 45 for transporting the document G from the document tray 42 to the paper discharge tray 47. Hereinafter, the direction along the transport path 45 is referred to as a transport direction. In FIG. 1, the conveyance direction is indicated by an arrow 81. Further, the side of the transport path 45 near the original tray 42 is called an upstream side, and the side of the transport path 45 near the paper discharge tray 47 is called a downstream side.

  The roller 46 is rotated by a motor M (see FIG. 2), conveys the document G placed on the document tray 42 along the transport path 45, and discharges the document G onto the discharge tray 47. That is, the roller 46 can be referred to as a conveyance unit 16 (see FIG. 2) that conveys the document G placed on the document tray 42 to the discharge tray 47.

  An F sensor 13 is disposed on the document tray 42. The F sensor 13 detects whether or not the document G is placed on the document tray 42. Further, an R2 sensor 14 is disposed at a detection position LK2 on the transport path 45. The R2 sensor 14 detects the presence or absence of the document G conveyed to the reading unit 60 by the ADF 40. Further, an R1 sensor 15 is disposed at a detection position LK1 on the transport path 45 downstream of the detection position LK2. The R1 sensor 15 detects the presence or absence of the document G conveyed to the reading unit 30 by the ADF 40.

  The reading unit 60 is disposed downstream of the detection position LK2 on the transport path 45 and upstream of the detection position LK1. The reading unit 60 is disposed in the ADF cover 41 and is supported so as not to move with respect to the ADF 40. The reading unit 60 reads an image on the back surface of the original G when the original G conveyed through the conveyance path 45 passes the reading position L <b> 2 on the third platen glass 55 facing the pressing member 43.

  The reading unit 30 is disposed on the downstream side of the detection position LK1 of the conveyance path 45. The reading unit 30 is disposed in the main body unit 2, and is disposed downstream of the reading unit 60 by a specified distance Z (see FIGS. 11 and 12) along the conveyance path 45. The reading unit 30 reads an image on the surface of the original G when the original G conveyed through the conveyance path 45 passes the reading position L <b> 1 on the second platen glass 53 facing the pressing member 44.

  Further, as shown by a dotted line in FIG. 1, the reading unit 30 is configured to be movable in the movement direction indicated by the arrow 82 within the main body unit 2, and is stationary on the first platen glass 52 while moving in the movement direction. Then, the lower surface of the original G placed thereon is read. In the following description, as indicated by a solid line in FIG. 1, the operation of the reading unit 30 that reads an image of the document G that is stationary at the reading position L1 and conveyed on the conveyance path 45 will be described.

  The reading unit 60 reads the document G by a so-called CIS method using a CIS (Contact Image Sensor). The reading unit 60 includes a light source 61 composed of a light emitting diode or the like, and a plurality of light receiving elements 63 arranged linearly in the main scanning direction D1. The light receiving element 63 is an example of a reading element. Note that the configuration of the reading unit 30 is basically the same as the configuration of the reading unit 60, and redundant description is omitted. However, the structures of the reading units 30 and 60 do not necessarily have the same structure. For example, one of the reading unit 30 and the reading unit 60 may be a CIS and the other may be a CCD.

  Furthermore, the reading device 1 includes a power switch and various setting buttons, and includes an operation unit 11 (see FIG. 2) that receives an operation command from the user, an LED or a liquid crystal display, and displays the status of the reading device 1. A display unit 12 (see FIG. 2) and the like are provided. The operation unit 11 is an example of a reception unit.

2. As shown in FIG. 2, the reading apparatus 1 includes a central processing unit (hereinafter referred to as CPU) 20, an image processing unit 25, a ROM 26, a RAM 27, an ASIC (Application Specific Integrated Circuit) 28, and a device control unit 17. The first correction circuit 18 and the second correction circuit 19 are provided, and the operation unit 11, the display unit 12, the sensors 13 to 15, the conveyance unit 16, and the like are electrically connected to them. As indicated by a solid line 21 in FIG. 2, an example of the control unit includes the CPU 20, the image processing unit 25, the ROM 26, the RAM 27, the ASIC 28, the device control unit 17, the first correction circuit 18, and the second correction circuit 19. is there.

  Various programs for controlling the operation of the reading device 1 are stored in the ROM 26, and the CPU 20 controls each part in accordance with the program read from the ROM 26 and executes a document reading process to be described later.

  The device control unit 17 transmits a reading control signal to the reading units 30 and 60 based on a command from the CPU 20. Each reading unit 30, 60 reads an image on each side of the document G based on a reading control signal from the device control unit 17.

  When reading the image on the back side of the original G conveyed through the conveyance path 45, the reading unit 60 repeats reading a plurality of times in the main scanning direction D1 perpendicular to the conveyance direction at the reading position L2 of the conveyance path 45. The reading section 60 acquires the analog signal line reading data YTU (see FIGS. 11 and 12A) by one reading in the main scanning direction D1, that is, reading one line, and secondly corrects the acquired line reading data YTU. Output to the circuit 19. The reading unit 60 is configured by repeating reading for each line in the main scanning direction D1, thereby collecting a plurality of line reading data YTU in the sub-scanning direction D2 (see FIGS. 11 and 12) orthogonal to the main scanning direction D1. Read data YU is output. The read data YU is an example of second read data.

  The second correction circuit 19 converts the analog line read data YTU output from the reading unit 60 into a digital signal, that is, gray scale data line read data YTU expressed using a gray scale value. The second correction circuit 19 performs shading correction and γ correction on the line read data YTU of the digital signal, and stores the line read data YTU after γ correction in the RAM 27. The gradation value is an example of image density.

  Similarly, when reading the image on the surface of the original G conveyed on the conveyance path 45, the reading unit 30 repeats reading in the main scanning direction D1 a plurality of times at the reading position L1 of the conveyance path 45. The reading unit 60 acquires the line reading data YTO (see FIGS. 11 and 12) of the analog signal by one reading in the main scanning direction D1, that is, reading one line, and performs first correction on the acquired line reading data YTO. Output to the circuit 18. The reading unit 30 repeats reading for each line in the main scanning direction D1, and outputs read data YO configured by collecting a plurality of line reading data YTO in the sub-scanning direction D2 orthogonal to the main scanning direction D1.

  The first correction circuit 18 converts the analog line read data YTO output from the reading unit 30 into digital signal, that is, gray scale data line read data YTO expressed using a gray scale value. The first correction circuit 18 performs shading correction and γ correction on the line read data YTO of the digital signal, and stores the line read data YTO after γ correction in the RAM 27.

  The image processing unit 25 performs image processing such as correction processing such as smoothing processing and edge enhancement processing such as binarization processing on the read data YO and YU stored in the RAM 27 based on a command from the CPU 20. A first image processing circuit 23 and a second image processing circuit 24 are provided. The CPU 20 performs correction processing on the line read data YTO and YTU of the read data YO and YU using the first image processing circuit 23 to generate output image data.

  Further, the CPU 20 uses the second image processing circuit 24 to perform edge emphasis processing on each line read data YTU of the read data YU to generate line emphasis data KTU. Then, emphasis data KU (12B in FIG. 12) configured by collecting a plurality of line emphasis data KTU in the sub-scanning direction D2 is generated. As shown in 12B of FIG. 12, the embossed data KU emphasizes the unevenness on the back surface of the document G. As a result, in the emphasis data KU, a concavo-convex image corresponding to the concavo-convex on the back surface of the original G appears even in the plain data portion where the original image such as characters and figures is not described.

The CPU 20 executes the following processing using the image processing unit 25.
The CPU 20 uses the image processing unit 25 to perform a plain color determination process for determining whether or not the line read data YTO and YTU stored in the RAM 27 are plain data. Hereinafter, the plain color determination processing of the line read data YTU will be described, but the same applies to the line read data YTO.

  The plain color determination process is performed for each line reading data YTU acquired by the reading unit 60. The CPU 20 obtains an average value of the gradation data acquired by each light receiving element 63 of the reading unit 60 and obtains a density difference between the average value and the second reference gradation value. When the density difference is less than the second density threshold, the CPU 20 determines that the original image is not included in the line read data YTU, that is, plain data. Further, when the density difference is equal to or greater than the second density threshold, the CPU 20 determines that the original image is included in the line read data YTU, that is, it is not plain data. The second reference gradation value and the second density threshold are the reference density and the first threshold set for the reading unit 60. The setting of the second reference gradation value will be described in the document reading process described later.

  In the plain color determination processing of the line read data YTO, the first reference gradation value and the first density threshold value are used instead of the second reference gradation value and the second density threshold value. The first reference gradation value and the first density threshold are the reference density and the first threshold set corresponding to the reading unit 30. The setting of the second reference gradation value will be described in the document reading process described later. Note that the representative value of the gradation data for which the density difference between the first reference gradation value and the second reference gradation value is obtained is not limited to the average value, and may be a median value or a peak value.

  In addition, the CPU 20 uses the image processing unit 25 to perform processing for determining whether or not a change has occurred in the line reading data YTO, YTU and line enhancement data KTU stored in the RAM 27. If there is no change in these data, it is highly likely that the document G is jammed on the transport path 45 and is not transported. Therefore, the above process can be called a jam determination process for determining whether or not the document G is jammed. In the following, the clogging determination process for the line read data YTU will be described, but the same applies to the line read data YTO and the line enhancement data KTU.

  The clogging determination process is performed for each line reading data YTU acquired by the reading unit 60. The CPU 20 obtains a difference value of gradation data for each light receiving element 63 with respect to two line reading data YTU continuous in the sub-scanning direction D2, and the light receiving element 63 obtains the difference value when the difference value is equal to or less than the change threshold value. It is determined that there is no change in the gradation data, that is, continuous data. Further, when the difference value is larger than the change threshold, the CPU 20 determines that a change has occurred in the two continuous line read data YTU, that is, it is not continuous data. The change threshold is an example of a second threshold.

  The CPU 20 executes the change determination process for the light receiving elements 33 included in the specified range KH. When the continuous data is included in the two line reading data YTO corresponding to the specified range KH at a change reference ratio or more, the CPU 20 does not change the two line reading data YTO to be compared, that is, the document G is jammed. Judge. On the other hand, if the continuous data is less than the change reference ratio, the CPU 20 determines that there is a change in the two line read data YTO to be compared, that is, the document G is not jammed. The change reference ratio is an example of a specified ratio.

3. Document Reading Processing Next, document reading processing will be described with reference to FIGS. When the CPU 20 confirms that the document G is placed on the document tray 42 using the F sensor 13 and receives a document reading instruction from the user via the operation unit 11, the CPU 20 starts document reading processing. .

  As shown in FIG. 3, when starting the document reading process, the CPU 20 accepts reading conditions such as the document size of the document G and the reading surface designation input to the operation unit 11 in accordance with the reading instruction (S 2), and enters the RAM 27. Remember. Further, the CPU 20 resets a jam counter JC and a normal transport counter NC which will be described later.

  Here, the reading surface designation means designation of the surface on which the original G is read. The front side reading designation for designating reading of the front side of the original G and the reverse side reading designation for designating reading of the back side of the original G are the same as those of the original G. It is an example of single-sided reading designation that designates single-sided scanning. In addition to single-sided scanning designation, there is double-sided scanning designation that designates scanning of both the front and back sides of the original G. In the document reading process of the present embodiment, both sides of the original G are read using the reading units 30 and 60, regardless of whether a single-sided reading designation or a double-sided reading designation is received from the user, and line reading data YTO, Based on YTU, the jam of document G is determined.

  Next, the CPU 20 instructs the transport unit 16 to transport the document G, starts transporting the document G (S4), and transports the document G at the first speed V1. When the conveyance of the document G is started, the CPU 20 detects the position of the document G being conveyed using the R2 sensor 14 (S6), and waits for the R2 sensor 14 to be turned on (S6: NO).

  When the R2 sensor 14 is turned on and the CPU 20 detects that the leading edge in the transport direction of the document G has reached the detection position LK2 of the transport path 45 (S6: YES), the transport direction of the document G from the document size received in S2 That is, the length in the sub-scanning direction D2 is acquired and compared with the specified distance Z (S8). If the length of the acquired document G in the sub-scanning direction D2 is equal to or longer than the specified distance Z (S8: YES), the CPU 20 executes a first transport reading process (S10).

(First transport reading process)
The first transport reading process will be described later in that it includes a double-sided determination process that simultaneously reads both sides of the original G using the reading units 30 and 60 and determines whether the original G is clogged from the output line reading data YTO and YTU. Different from the second transport reading process. “Reading at the same time” is not limited to reading at the same time, but if the reading units 30 and 60 read the original G in a state where the original is at a predetermined position on the conveyance path 45, the timing is completely set. It does not have to be simultaneous.

  As shown in FIG. 4, when starting the first transport reading process, the CPU 20 first causes the reading unit 60 to read one line of the leading edge of the back surface of the document G, and reads line leading data YTU obtained by reading the leading edge of the back surface of the document G. The back surface leading edge reading data YSU (see FIGS. 11 and 12) is output (S22). The CPU 20 obtains the average value of the gradation data of the back surface leading edge read data YSU using the image processing unit 25 and stores the acquired average value in the RAM 27 as the second reference gradation value (S24).

  Next, the CPU 20 detects the position of the document G being conveyed using the R1 sensor 15 (S26). If the R1 sensor 15 is off (S26: NO), the CPU 20 executes a single-sided reading process for reading the back side of the document G (S28).

(Single-sided scanning process)
As shown in FIG. 5, when the one-side reading process is started, the CPU 20 first performs a first determination process for reading one line of the back surface of the document G and determining the jamming of the document G using the read line reading data YTU. Execute (S50).

(First judgment reading process)
As shown in FIG. 6, when starting the first determination process, the CPU 20 first resets the first state flag RT1 indicating the conveyance state of the original G to “normal conveyance” (S62). Next, the CPU 20 causes the reading unit 60 to read one line of the back side of the document G (S64), and executes a plain color determination process for determining whether the read line read data YTU is plain data (S66, S68). ).

  In the plain color determination process, the CPU 20 obtains an average value of the gradation data of the read line read data YTU, and obtains a density difference between the obtained average value and the second reference gradation value (S66). The CPU 20 compares the acquired density difference with the second density threshold (S68), and if the acquired density difference is less than the second density threshold (S68: NO), the line read data YTU is plain data. Determination is made (S70), and the first determination process is terminated.

  On the other hand, if the acquired density difference is greater than or equal to the second density threshold (S68: YES), the CPU 20 determines that the line read data YTU is not plain data (S72), and executes a clogging determination process (S74). That is, the CPU 20 executes the clogging determination process based on the line reading data YTU determined not to be plain data.

(Clogging judgment process)
The clogging determination process will be described with reference to FIGS. 7, 11, and 12. 11A shows the read data YO and YU when the original G including the original image on both sides is normally conveyed. The read data YO includes the original “A” described on the surface of the original G. An image is included, and the read data YU includes a document image “Z” written on the back side of the document G. 11B shows read data YO and YU when the original G including the original image on both sides is not normally conveyed, that is, the original G is jammed.

  12A indicates read data YO and YU when the original G including the original image only on the front side is normally conveyed, and includes the original image “A” described on the front side of the original G. Thus, the read data YU does not include a document image. 12B in FIG. 12 shows read data YO and emphasized data KU obtained by performing edge emphasis processing on the read data YU.

  As shown in FIG. 7, when the clogging determination process is started, the CPU 20 first calculates the ratio of continuous data included in these line read data YTU using the two most recently acquired line read data YTU. (S82), the calculated ratio is compared with the change reference ratio (S84). When the ratio of continuous data included in the two most recently acquired line reading data YTU is greater than or equal to the change reference ratio (S84: YES), the CPU 20 changes to the two most recently acquired line reading data YTU. If it is determined that the error has not occurred, the normal conveyance counter NC is reset (S86), and the jam counter JC is incremented by 1 (S88).

  Next, the CPU 20 compares the jam counter JC with a predetermined jam prescribed number JK (S90). Here, the prescribed jam number JK is 2 or 3, for example, and is set to an integer of 2 or more. If the jam counter JC is less than the jammed number JK (S90: NO), the CPU 20 determines that the document G is not jammed, and ends the jam determination process and the first determination process (see 11A in FIG. 11).

On the other hand, the CPU 20 determines that the jam counter JC is equal to or larger than the jammed number JK (S90: YES), that is, the jammed number JK of line read data YTU continuous in the sub-scanning direction D2.
If there is no change, it is determined that the original G is jammed. Here, the jammed document G means that the document G is not transported by the transport unit 16 due to insufficient transport torque of the motor M, for example. Further, for example, it means that the original G is deformed into a bellows shape in the conveyance path 45 and the original G is not normally conveyed. In this case, as shown by 11B in FIG. 11, the reading unit 60 reads the same portion of the original G after the timing when the original G is no longer conveyed, and the line read data YTU hardly changes.

  In this case, the CPU 20 checks the conveyance speed of the document G (S92), and when the document G is conveyed at the first speed V1 (S92: YES), the first state flag RT1 is set to “conveyance error occurred”. After switching (S94), the clogging determination process and the first determination process are terminated. On the other hand, when the document G is conveyed at the second speed V2 that is slower than the first speed V1 (S92: NO), the jam determination process and the first determination process are terminated without switching the first state flag RT1.

  On the other hand, when the ratio of continuous data in the two most recently acquired line read data YTU is less than the change reference ratio (S84: NO), the CPU 20 acquires the latest data as shown in 11A of FIG. If it is determined that there is a change in the two line reading data YTU, it is determined that the document G is not jammed, and the jam counter JC is reset (S96). Then, the CPU 20 confirms the conveyance speed of the original G (S98). If the original G is not conveyed at the second speed V2 and is conveyed at the first speed V1 (S98: NO), the jam determination process is performed. And the 1st judgment processing is ended.

  If the original G is being conveyed at the second speed V2 (S98: YES), the CPU 20 increments the normal conveyance counter NC by 1 (S100), and sets the normal conveyance counter NC to a predetermined normal specified number NK. (S102). Here, the normal specified number NK is, for example, 2 or 3, and is set to an integer of 2 or more. When the normal conveyance counter NC is less than the normal specified number NK (S102: NO), the CPU 20 ends the clogging determination process and the first determination process without switching the first state flag RT1.

  On the other hand, when the normal conveyance counter NC is equal to or greater than the normal specified number NK (S102: YES), the CPU 20 switches the first state flag RT1 to “carrying error release” (S104), and performs the jam determination process and the first determination process. finish.

  When completing the first determination process, the CPU 20 returns to the single-sided reading process shown in FIG. 5 and checks the state of the first state flag RT1 (S52, S54). When the first state flag RT1 is “conveyance error occurrence” (S52: YES), the CPU 20 determines that the document G is jammed. In this case, the CPU 20 reduces the conveyance speed of the original G to the second speed V2 (S56), and ends the single-sided reading process.

  Further, when the first state flag RT1 is “conveyance error release” or “normal conveyance” (S52: NO), the CPU 20 determines that the document G is not jammed and executes various processes. Specifically, when the first state flag RT1 is “carry error cancellation” (S54: YES), the conveyance speed of the original G is accelerated to the first speed V1 (S58), and the single-sided reading process is ended. Further, when the first state flag RT1 remains “normal conveyance” (S54: NO), the CPU 20 ends the one-side reading process without changing the conveyance speed of the original G.

  When the CPU 20 completes the one-side reading process, the CPU 20 repeatedly executes the one-side reading process until the R1 sensor 15 is turned on in the first transport reading process shown in FIG. Then, when the CPU 20 detects that the leading edge in the conveyance direction of the document G has reached the detection position LK1 of the conveyance path 45 (S26: YES), the CPU 20 detects the leading edge of the surface of the document G on the reading unit 60. Is read, and the front end read data YSO (see FIGS. 11 and 12), which is the line read data YTO obtained by reading the front end of the surface of the original G, is output (S30). The CPU 20 obtains the average value of the gradation data of the front end read data YSO using the image processing unit 25, and stores the acquired average value in the RAM 27 as the first reference gradation value (S32).

  Next, the CPU 20 detects the position of the document G being conveyed using the R2 sensor 14 (S34). If the R2 sensor 14 is on (S34: NO), the CPU 20 executes a double-sided reading process for reading both sides of the document G (S36).

(Double-sided scanning)
As shown in FIG. 8, when the double-sided reading process is started, the CPU 20 first performs a first determination process of reading one line of the surface of the document G and determining the jamming of the document G using the read line reading data YTO. Execute (S112). The first determination process is the above-described first determination process that is executed using the line reading data YTO, the first reference gradation value, and the first density threshold value, and redundant description is omitted.

  The CPU 20 reads one line of the back side of the document G, and executes a second determination process for determining whether the document G is clogged using the read line reading data YTU and the determination result of the first determination process (S112) ( S114).

(Second judgment reading process)
As shown in FIG. 9, when the second determination process is started, the CPU 20 first indicates the conveyance state of the document G, and resets the second state flag RT2 different from the first state flag RT1 to “normal conveyance” ( S132). Next, the CPU 20 causes the reading unit 60 to read one line of the back side of the document G (S134), and executes a plain color determination process for determining whether or not the read line read data YTU is plain data (S136, S138). ).

  In the plain color determination process, the CPU 20 obtains the average value of the gradation data of the read line read data YTU, and obtains the density difference between the acquired average value and the second reference gradation value (S136). Further, the CPU 20 compares the acquired density difference with the second density threshold (S138), and when the acquired density difference is equal to or larger than the second density threshold (S138: YES), the line reading data YTU is not plain data. (S140), and a clogging determination process is executed (S142). The clogging determination process is the above-described clogging determination process executed using the line reading data YTU, and a duplicate description is omitted. When the CPU 20 ends the clogging determination process, the CPU 20 ends the second determination process.

  If the acquired density difference is less than the second density threshold (S138: NO), the CPU 20 determines that the line read data YTU is plain data (S144). In this case, the CPU 20 confirms whether or not the line read data YTO read in the first determination process of S112 is determined to be plain data (S146). When it is determined that the line read data YTO read in the first determination process of S112 is plain data (S146: YES), the CPU 20 reads the line read data YTO read in the first determination process of S112. If it is determined that both the line reading data YTU read in the second determination process of S114 are plain data, the second determination process ends.

  On the other hand, as shown in 12A of FIG. 12, the CPU 20 determines that the line read data YTO read in the first determination process of S112 is not plain data (S146: NO), that is, the first of S112. When it is determined that the line read data YTO read in the determination process is not plain data, and the line read data YTU read in the second determination process of S114 is determined to be plain data, the CPU 20 performs the image processing unit 25. The second image processing circuit 24 is used to perform edge enhancement processing on the line read data YTU to generate line enhancement data KTU (S148, see 12B in FIG. 12). Then, the CPU 20 executes a clogging determination process using the generated line emphasis data KTU (S142). The clogging determination process is the above-described clogging determination process executed using the line emphasis data KTU, and a duplicate description is omitted. When the CPU 20 ends the clogging determination process, the CPU 20 ends the second determination process.

  When the CPU 20 completes the second determination process, the CPU 20 returns to the double-sided reading process shown in FIG. 8, and checks the states of the first state flag RT1 and the second state flag RT2 (S116 to S122). When the first state flag RT1 is “conveyance error occurrence” and the second state flag RT2 is “conveyance error occurrence” (S116: YES, S118: YES), the CPU 20 performs the first determination in S112. When it is determined that the document G is jammed based on the line read data YTU read in the process, and it is determined that the document G is jammed based on the line read data YTO read in the second determination process of S114 It is determined that the original G is jammed. In this case, the CPU 20 decelerates the conveyance speed of the original G to the second speed V2 (S124), and ends the double-sided reading process.

  On the other hand, when at least one of the first state flag RT1 and the second state flag RT2 is not “conveyance error occurrence” (S116: YES, S118: YES), the CPU 20 reads the line read in the first determination process of S112. If it is determined that the document G is not jammed in at least one of the read data YTU and the line reading data YTO read in the second determination process of S114, it is determined that the document G is not jammed and various processes are performed. Run.

  Specifically, the CPU 20 determines that the first state flag RT1 is “conveyance error occurrence” and the second state flag RT2 is “normal conveyance” or “conveyance error release” (S116: YES, S118). : NO), the double-sided reading process is terminated without changing the conveyance speed of the original G.

  In addition, when the first state flag RT1 is “conveyance error release” (S116: NO, S120: YES), the CPU 20 sets the conveyance speed of the document G to the first speed V1 regardless of the state of the second state flag RT2. (S126), and the double-sided reading process ends.

  Further, when the first state flag RT1 is “normal conveyance” (S116: NO, S120: NO), and the second state flag RT2 is “conveyance error release” (S122: YES), the CPU 20 The conveyance speed of G is accelerated to the first speed V1 (S128), and the double-sided reading process is terminated. On the other hand, when the second state flag RT2 is “normal transport” or “transport error has occurred” (S122: NO), the CPU 20 ends the duplex reading process without changing the transport speed of the document G. To do.

  When the double-sided reading process is completed, the CPU 20 repeatedly executes the double-sided reading process until the R2 sensor 14 is turned off in the first transport reading process shown in FIG. Then, when the CPU 20 detects that the R2 sensor 14 is turned off and the trailing end in the transport direction of the document G has reached the detection position LK2 of the transport path 45 (S34: YES), the reading of the back surface of the document G is finished. (S38).

  Next, the CPU 20 detects the position of the document G being conveyed using the R1 sensor 15 (S40). If the R1 sensor 15 is on (S40: NO), the CPU 20 executes a single-sided reading process for reading the surface of the document G (S42). The single-sided reading process is the above-described single-sided reading process that is executed by using the read line reading data YTO, the first reference gradation value, and the first density threshold while reading one line of the surface of the original G. The description that has been made will be omitted.

  The CPU 20 repeatedly executes the single-sided reading process until the R1 sensor 15 is turned off. Then, when the CPU 20 detects that the R1 sensor 15 is turned off and the trailing edge in the conveyance direction of the document G has reached the detection position LK1 of the conveyance path 45 (S40: YES), the reading of the surface of the document G is finished. (S44), the first transport reading process is terminated.

  On the other hand, in the document reading process shown in FIG. 3, when the length of the acquired document G in the sub-scanning direction D2 is less than the specified distance Z (S8: NO), the CPU 20 executes the second transport reading process (S12). .

(Second transport reading process)
The second transport reading process includes only the one-side determination process for determining whether or not the document G is jammed from the line reading data YTO and YTU obtained by separately reading both sides of the document G using the reading units 30 and 60. This is different from the one transport reading process. Note that the same process as the first transport reading process is denoted by the same step number, and a duplicate description is omitted.

  As shown in FIG. 10, the CPU 20 starts the second conveyance reading process, and stores the average value of the gradation data of the back surface leading edge reading data YSU as the second reference gradation value in the RAM 27 (S24). Is used to detect the position of the document G being conveyed (S152). If the R2 sensor 14 is on (S152: NO), the CPU 20 repeatedly executes the single-sided reading process for the back side of the document G until the R2 sensor 14 is turned off (S28).

  Then, when the CPU 20 detects that the R2 sensor 14 is turned off and the trailing end in the conveyance direction of the document G has reached the detection position LK2 of the conveyance path 45 (S152: YES), the reading of the back surface of the document G is finished. (S154).

  Next, the CPU 20 detects the position of the document G being conveyed using the R1 sensor 15 (S156), and waits for the R1 sensor 15 to be turned on (S156: NO). When the R1 sensor 15 is turned on and the CPU 20 detects that the leading edge in the conveyance direction of the document G has reached the detection position LK1 of the conveyance path 45 (S156: YES), the average value of the gradation data of the front surface leading edge reading data YSO Is stored in the RAM 27 as the first reference gradation value (S32).

  The CPU 20 detects the position of the document G being conveyed using the R1 sensor 15 (S160), and if the R1 sensor 15 is on (S160: NO), the CPU 20 continues until the R1 sensor 15 is turned off. The single-sided reading process for the surface is repeatedly executed (S42). When the R1 sensor 15 is turned off and it is detected that the trailing edge in the conveyance direction of the document G has reached the detection position LK1 of the conveyance path 45 (S160: YES), the CPU 20 finishes reading the surface of the document G. (S162) The second transport reading process is terminated.

  When the CPU 20 completes the first transport reading process (S10) or the second transport reading process in the document reading process shown in FIG. 3, the CPU 20 causes the transport unit 16 to transport the document G to the paper discharge tray 47 (S14). ), And waits for the original G to be discharged to the discharge tray 47 (S14: NO). Then, when the original G is discharged onto the discharge tray 47 (S14: YES), the CPU 20 ends the original reading process.

4). Effects of the Present Embodiment In the present embodiment described above, the CPU 20 reads the read data YO output by the reading unit 30 reading the original G at the reading position L1, and the reading unit 60 reads the original G at the reading position L2 and outputs it. Based on the read data YU, it is determined whether or not the document G is clogged (S90: YES). Thereby, it is possible to detect whether or not the document G is jammed at the reading positions L1 and L2.

  In the present embodiment described above, the CPU 20 uses the line reading data YTO and YTU determined not to be plain data when detecting whether or not the document G is jammed at the reading positions L1 and L2 (S72 and S140). Accordingly, it is possible to accurately determine whether or not the document G is clogged from the change in the document image included in the line read data YTO and YTU, compared to the case where the line read data YTO and YTU determined to be plain data are used. .

  In the above-described embodiment, the CPU 20 performs line reading data based on the density difference between the line reading data YTO and the first reference gradation value, or the density difference between the line reading data YTU and the second reference gradation value. It is determined whether YTO and YTU are plain data (S68, S138). Thereby, it is easy to determine whether or not the line reading data YTO and YTU are plain data.

  In the present embodiment described above, the CPU 20 sets the first reference gradation value from the front surface leading edge reading data YSO output by reading the leading edge of the document G (S24), and the second reference gradation from the back surface leading edge reading data YSU. A value is set (S32). Thereby, the reference gradation value corresponding to the original G can be set. Further, by using the leading edge reading data, the time from the reading start of the document G to the determination of the jamming of the document G is shortened compared to the case of using the line reading data YTO and YTU output after that. be able to.

  In the present embodiment described above, the CPU 20 calculates the ratio of continuous data included in the two most recently acquired line reading data YTO, YTU and line emphasis data KTU, and the ratio is equal to or greater than the change reference ratio. When it is determined that no change has occurred in the data of the document G, it is determined that the document G is jammed (S84: YES). Thereby, the CPU 20 can accurately determine that the original G is jammed and the original G stops at the reading positions L1 and L2, and that the line reading data YTO and YTU and the line emphasis data KTU are not changed. .

  In the present embodiment described above, the CPU 20 determines whether or not the document G is clogged based on the line reading data YTO output by reading the front surface of the document G and the line reading data YTU output by reading the back surface of the document G. Judgment is made (S116, S118). Accordingly, it is possible to accurately determine whether or not the document G is clogged as compared with the case where the document G is determined to be clogged based on one of the read data.

  Specifically, in the double-sided reading process of the first transport reading process, when it is determined that the original G is clogged with both line reading data YTO and line reading data YTU read simultaneously, the original G (S116: YES, S118: YES). Thereby, it is possible to accurately determine the occurrence of jamming of the original G.

  In the double-sided reading process of the first transport reading process, when it is determined that the line reading data YTO is not plain data and the line reading data YTU is determined to be plain data, an edge enhancement process is performed on the line reading data YTU. Is executed to generate the line emphasis data KTU (S148), and it is determined whether or not the document G is clogged based on the line reading data YTO and the line emphasis data KTU.

  If the line reading data YTU is plain data, no change appears in the line reading data YTU regardless of whether or not the document G is jammed. Therefore, it is possible to determine whether or not the document G is jammed based on the line reading data YTU. Can not. On the other hand, since the line emphasis data KTU includes a concavo-convex image, it is possible to determine whether the document G is clogged from the change in the concavo-convex image.

  In the present embodiment, when it is determined that the line read data YTO is not plain data and the line read data YTU is determined to be plain data, the document G is read based on the line read data YTO and the line emphasis data KTU. By determining the presence or absence of clogging, even when the original image is not included in the positions corresponding to the reading positions L1 and L2 on both sides of the original G, such as the original G including the original image only on the front surface, the line Based on the read data YTO and the line read data YTU, it can be determined whether or not the document G is jammed.

  In the present embodiment described above, the CPU 20 reads both sides of the original G using the reading units 30 and 60 and receives the line reading data YTO regardless of whether the single side reading designation or the double side reading designation is received from the user. The jam of the original G is determined based on YTU (S10, S12). Thereby, even when a single-sided reading designation is received from the user, it is possible to accurately determine whether or not the document G is clogged based on the line reading data YTO and the line reading data YTU.

  In the above-described embodiment, the CPU 20 compares the length in the sub-scanning direction D2 of the document G acquired from the document size received from the user with the specified distance Z, and performs the first transport reading process including the duplex scanning process. Or whether to execute the second transport reading process including only the single-sided reading process (S8). Accordingly, it is possible to determine whether or not the document G is clogged together with the document G to be conveyed.

  In the present embodiment described above, the CPU 20 determines whether or not the document G is clogged each time the line reading data YTO and YTU are output from the reading units 30 and 60 (S74 and S142). As a result, compared with the case where it is determined whether or not the document G is jammed after the number of line read data YTO and YTU corresponding to the entire read data YO and YU is output, the occurrence of jamming of the document G is detected. Time can be shortened.

  In the present embodiment described above, the CPU 20 determines that the document G is clogged when the line reading data YTO, YTU and the line emphasis data KTU have not changed more than a predetermined number of events (S90: YES). ). Accordingly, it is possible to suppress erroneous determination of the jamming of the document G as in the case where it is determined that the document G is jammed when the event occurs by chance once.

  In the present embodiment described above, the CPU 20 reduces the conveyance speed of the conveyance unit 16 from the first speed V1 to the second speed V2 in response to determining that the document G is jammed (S56, S124). As a result, the document G that cannot be transported at the first speed V1 and has become jammed can be transported at the second speed V2.

  In the present embodiment described above, the CPU 20 determines that the jamming of the document G has been eliminated when the transport speed of the transport unit 16 is reduced to the second speed V2 due to the jamming of the document G. Accordingly, the transport speed of the transport unit 16 is returned to the first speed V1. Thereby, the reading time of the original G can be shortened compared with the case where the state where the conveyance speed is lowered is continued.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and the drawings, and for example, the following various aspects are also included in the technical scope of the present invention.

  The “reading device” is not limited to the reading device 1 having a scanner function, and may be a multifunction device having a printer function, a copy function, a facsimile function, and the like.

  The “control unit” is configured to execute each process such as a conveyance reading process by one CPU 20. However, the present invention is not limited to this. For example, a configuration in which each processing is executed by a plurality of CPUs, a configuration in which each processing is executed only by a hardware circuit such as the ASIC 28, or a configuration in which each processing is executed by one or a plurality of CPUs and ASICs. . The ASIC may include the device control unit 17, the first correction circuit 18, the second correction circuit 19, and the like.

  Further, the program executed by the CPU 20 is not necessarily stored in the ROM 26, and may be stored in the CPU 20 itself or in another storage device.

  When calculating the “image density of the front end line read data”, if the average value of all the lines of the front end front end read data YSO (back side front end read data YSU) can be obtained, for example, the average of a specific area such as the central part A value may be obtained. By limiting to the specific region, it is possible to reduce the burden on the CPU 20 when obtaining the average value compared to the case where all the lines are used. The same applies to the determination of the median and peak values.

23: first image processing circuit, 24: second image processing circuit, 25: image processing unit, 30: reading unit, 33: light receiving element, 45: transport path, 60: reading unit, 63: light receiving element, D1: main Scanning direction, D2: Sub-scanning direction, JC: Jam counter, NC: Normal conveyance counter, RT1: First state flag, RT2: Second state flag, YO, YU: Reading data, YTO, YTU: Line reading data, KTU : Line emphasis data, YSO: Front end read data, YSU: Back end read data, Z: Specified distance

Claims (4)

A transport section;
A first reading unit that outputs first reading data corresponding to an image on the surface of the document passing through the first reading position;
A second reading unit that outputs second reading data corresponding to an image on the back side of the document passing through the second reading position;
A control unit,
The controller is
The first reading unit performs an output operation for outputting first reading data corresponding to an image of a document that is conveyed by the conveying unit and passes through the first reading position, and is conveyed by the conveying unit to be subjected to the second reading. and an output operation to output a second read data corresponding to an image of the document passing through the position, reading that was done to the second reading unit process,
First enhancement data in which the change in image density is emphasized is generated from the first read data output from the first reading unit, and the change in image density is emphasized from the second read data output from the second reading unit. Enhancement processing for generating second enhancement data;
A plain color determination process for determining whether the first read data output by the first reading unit and the second read data output by the second reading unit are plain data;
It is determined that one of the first read data and the second read data is not plain data, and the other of the first read data and the second read data is plain data. in response to the determined, the relative one of the read data to determine the presence or absence of clogging of the document based on one of the read data and the said for other read data corresponding to the other of reading data A jam determination process for determining whether or not a document is jammed based on the first emphasized data or the second emphasized data ;
A reading device. The reading device according to claim 1 ,
It has a reception part,
The first reading position and the second reading position are separated by a specified distance along a transport path along which the document is transported by the transport unit,
The controller is
A reception process for receiving a document size from the reception unit;
In the jam determination process, in response to receiving a document size whose length in the sub-scanning direction is equal to or greater than the specified distance in the receiving process, the document is read based on the first read data and the second read data that are read simultaneously. Based on the first read data and the second read data read separately in response to receiving a document size whose length in the sub-scanning direction is less than the specified distance is determined in the receiving process. A reading device that determines whether a document is jammed. The reading device according to claim 1 or 2 ,
The controller is
In the reading process, when the document is conveyed to the conveyance unit at the first speed and it is determined in the jam determination process that the document is jammed, the conveyance unit receives the first speed. A reading apparatus that conveys a document at a second speed slower than the second speed. The reading device according to claim 3 ,
The controller is
In the reading process, when the document is transported to the transport unit at the second speed and it is determined that the document is not jammed in the jam determination process, the transport unit is configured to transfer the first speed. A scanning device that transports the document with

Images