JP2014150376A - Image reading apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine the occurrence of an original sheet jam.SOLUTION: In an image reading apparatus 1, a CIS 30 comprises: a passage region E1; and lateral regions E2 positioned on the lateral sides of the passage region E1. When reading the original sheet SH by using the CIS 30, standard lateral images G2 that are lateral images G2 obtained by reading an original pressing member 46 corresponding to the lateral regions E2 are acquired when the original sheet SH reaches a reading position P1. During reading of the original sheet SH, images of the lateral regions E2 are also acquired together with an image of the passage region E1. It is determined whether or not jamming of the original sheet SH has occurred by comparing the lateral images G2 acquired during reading of the original sheet SH with the standard lateral images G2.

Description

  The present invention relates to a technique for moving an original sheet to read an image on the original sheet, and more particularly to a technique for determining that a jam has occurred during movement of the original sheet.

  There is an image reading apparatus of a type that reads an image on the original sheet while moving the original sheet with respect to the image reading section and passing the reading position of the image reading section. In this type of image reading apparatus, a jam may occur during movement of a document sheet, and a technique for determining whether a jam has occurred in a document sheet is known (for example, Patent Document 1).

  A conventional image reading apparatus has an original position detection sensor for confirming passage of an original sheet, and the original is detected when the leading edge or the rear end of the original sheet does not pass the original position detection sensor within a predetermined time. Determine whether a sheet has jammed. If a jam occurs in the original sheet, the difference in reflectance between the reflective member disposed opposite to the image reading unit and the original sheet is used to leave the original sheet between the reflective member and the image reading unit. Judge whether or not.

JP 2009-194703 A

  By the way, when it is determined whether or not a jam has occurred on a document sheet using a predetermined time as in the conventional image reading apparatus, a jam has occurred on a document sheet unless a predetermined time has elapsed. I cannot judge whether or not. For this reason, when it is determined that a jam has occurred on the original sheet, the original sheet may already be bent, so that it may not be possible to perform another reading using the original sheet. A technique for judging is desired.

  The present specification discloses a technique for determining that a jam has occurred in an original sheet.

  An image reading apparatus disclosed in this specification includes a moving unit that moves a document sheet with respect to a predetermined reading position, and a main scanning direction orthogonal to the moving direction of the moving unit at the reading position. An image reading unit that reads an image in the read region and includes a pass region and a side region located to the side of the pass region, and the image read unit is disposed to face the image read unit across the read region. A counter member, and a control unit. The control unit causes the image reading unit to read when the document sheet reaches the reading position, and reads the counter member corresponding to the side region. A data acquisition process for acquiring side area data; a read process for causing the image reading unit to read the original sheet after the data acquisition process; and a data acquisition process during the read process. If the value of the side area data thus obtained and the value of the side area data acquired in the reading process differ beyond a predetermined range, it is determined that a jam has occurred in the original sheet. Determination processing to be executed.

  In this image reading apparatus, the reading area of the image reading unit includes a side area located on the side of the passing area in addition to the passing area. When the image reading unit reads the original sheet, the side area data corresponding to the side area is read, and this is acquired when the standard side area data, that is, the original sheet reaches the reading position. Compared with the side area data, it is determined that a jam has occurred on the original sheet. According to this image reading apparatus, it is determined during reading of a document sheet that a jam has occurred in the document sheet by using the side area data acquired when the document sheet is read. As a result, unlike the prior art, it is not necessary to wait for a predetermined time to elapse before it is determined whether or not a jam has occurred on the original sheet, and the occurrence of the jam is determined earlier than before. Can do.

  In the above image reading apparatus, when the thickness of the original sheet between the image reading unit and the facing member is thick, the image reading unit is farther from the image reading unit than when the original sheet is thin. A displacement unit that displaces the facing member at a position, and the control unit includes the side in which the value of the side area data acquired in the reading process is acquired in the data acquisition process in the determination process. A configuration may be adopted in which it is determined that a jam has occurred in the original sheet when the value falls below the first reference value compared to the value of the direction area data.

  In this image reading apparatus, the opposing member is displaced to a position farther from the image reading unit when the thickness of the original sheet between the opposing side of the image reading unit is thicker than when the original sheet is thin. For this reason, the value of the side area data acquired from the image reading unit is that the original sheet normally exists between the opposing faces when the original sheet is jammed and the original sheets are folded between the opposing faces. That is, as compared with the case where the overlapping member does not exist in a folded state, it is lowered by the amount the opposing member is displaced to a far position. According to this image reading apparatus, it is possible to determine whether or not a jam has occurred in the document sheet when the value of the side area data has decreased below the first reference value by utilizing this fact. it can.

  In the above image reading apparatus, the image reading unit further includes a correction unit that performs inclination correction on the read data obtained by reading the original sheet, and each side region is adjacent to the passage region and the main region. A width in the scanning direction has a first side region determined based on a limit inclination angle that the correction unit can correct the inclination, and a second side region located outside the first side region, In the data acquisition process and the reading process, the control unit is side area data corresponding to the first side area, the first side area data including a plurality of pixel data, and the first side area data. Second side area data corresponding to two side areas, and in the determination process, the value of the second side area data acquired in the reading process is acquired in the data acquisition process. Second side It is determined that a jam has occurred in the original sheet when the value falls below the first reference value compared to the value of the area data, and the second side area acquired in the reading process is further determined. Even if the data value is not lower than the first reference value compared to the value of the second lateral area data acquired in the data acquisition process, the data value is acquired in the reading process. In addition, all the pixel data constituting the first side area data and the representative value of the pixel data constituting the first side area data acquired in the data acquisition process have the second reference value. A configuration may be adopted in which it is determined that a jam has occurred in the original sheet when the difference is greater than the above. Here, the representative value means an average value, an intermediate value, a maximum value, a minimum value, or the like.

  In general, the reflectance of the document sheet and the facing member is different, and the value of the pixel data read from the facing member is different from the value of the pixel data read from the document sheet that has entered the first side region due to the inclination of the document sheet. In this image reading apparatus, when the first side area data is different from the standard side area data in the entire first side area of the side areas, that is, the original sheet is the first side area data. When the original sheet is tilted so as to reach the entire area, it is determined that the original sheet is jammed. According to this image reading apparatus, it is possible to determine whether or not a jam has occurred in the original sheet based on whether or not the inclination correction by the correction unit can be performed. The inclination correction can be performed on the read data using the correction unit.

  In the image reading apparatus, the side areas are provided on both sides of the passage area, and the control unit acquires the side area data for each side area in the data acquisition process and the reading process. In the determination process, for each side area, the value of the side area data acquired in the data acquisition process is compared with the value of the side area data acquired in the reading process. In at least one of the side areas, the value of the side area data acquired in the data acquisition process and the value of the side area data acquired in the reading process exceed a predetermined range. A configuration may be adopted in which it is determined that a jam has occurred in the original sheet when they are different.

  In this image reading apparatus, the side areas are provided on both sides of the passage area. When it is determined that a jam has occurred on the original sheet, the occurrence of a jam is determined when the side area data of at least one side area satisfies a predetermined condition. Therefore, it is possible to accurately determine the occurrence of jam as compared with the case where the side area is provided only on one side of the passing area.

  In the image reading apparatus, the control unit may further execute a stop process for stopping the movement of the original sheet when it is determined in the determination process that a jam has occurred in the original sheet. good.

  According to this image reading apparatus, it is possible to suppress the occurrence of an event such as bending of the document sheet by moving the document sheet determined to have jammed.

  With the image reading device disclosed in this specification, it can be determined earlier than before that a jam has occurred in a document sheet.

Schematic sectional view of an image reading device Schematic view of CIS and document holding member viewed from the front Explanatory drawing of displacement of distance between CIS and document holding member Block diagram schematically showing the electrical configuration of the image reading apparatus Flow chart showing the reading process Flow chart showing jam detection processing Figure showing a document sheet and its scanned image Figure showing a document sheet and its scanned image Figure showing a document sheet and its scanned image

<Embodiment>
One embodiment will be described with reference to FIGS.

1. As shown in FIG. 1, the image reading apparatus 1 transports a plurality of document sheets SH placed on a paper feed tray 2 by a user to a paper discharge tray 4 and is currently transporting. This is a sheet feed scanner that reads the original sheet SH using the CIS 30 included in the main body 3. The CIS 30 is an example of an image reading unit.

  The main body 3 of the image reading apparatus 1 is provided with a conveyance path 22 that connects the paper feed tray 2 and the paper discharge tray 4. A paper feed roller 40, a separation pad 42, and the periphery of the conveyance path 22 are provided. , A transport roller 44, a document pressing member 46, a CIS 30, a paper discharge roller 50, a front sensor (hereinafter referred to as F sensor) 13, and a rear sensor (hereinafter referred to as R sensor) 14. The document pressing member 46 is an example of a facing member.

  The paper feed roller 40 is rotationally driven by a motor M (see FIG. 3). The paper feed roller 40 abuts on the original sheet SH placed on the paper feed tray 2, and pulls the original sheet SH placed on the paper feed tray 2 into the main body 3 by a frictional force. At this time, the document sheet SH is separated for each document sheet SH by the frictional force of the separation pad 42 and sent out to the conveyance path 22.

  The transport roller 44 is driven to rotate by the motor M and transports the original sheet SH drawn into the main body 3 by the paper feed roller 40 along the transport path 22. The CIS 30 is arranged at the reading position P1 on the conveyance path 22 and reads an image of the original sheet SH conveyed in the conveyance direction H2 along the conveyance path 22 at the reading position P1. A document pressing member 46 that presses the document sheet SH on the conveyance path 22 against the CIS 30 side by the elastic force of the spring 48 is disposed at a position facing the CIS 30 at the reading position P1. The document pressing member 46 is configured to be displaced in the vertical direction by a spring 48. The conveyance direction H2 is an example of a movement direction, and the spring 48 is an example of a displacement part.

  A paper discharge roller 50 is disposed on the downstream side of the reading position P <b> 1 on the conveyance path 22. The paper discharge roller 50 is rotationally driven by the motor M similarly to the paper feed roller 40 and the transport roller 44, and sends the document sheet SH transported on the transport path 22 to the paper discharge tray 4. That is, the transport unit 15 (the transport unit 15) moves the plurality of document sheets SH placed on the paper feed tray 2 along the transport path 22 including the reading position P 1 by the paper feed roller 40, the transport roller 44, and the paper discharge roller 50. 3) is formed. The transport unit 15 is an example of a moving unit.

  A protruding portion 52 that protrudes upward is provided on the conveyance path 22 side of the discharge tray 4, and the conveyance path 22 side of the document sheet SH sent to the discharge tray 4 warps upward in accordance with the protruding portion 52. Go up. For this reason, the original sheet SH conveyed later along the conveyance path 22 is the original sheet SH conveyed first, and the original sheet SH warped upward as a result of being sent to the paper discharge tray 4. The sheet SH and the protruding portion 52 are fed out, that is, so as to sink into the lower side of the original document sheet SH conveyed earlier. As a result, a plurality of document sheets SH placed in order from the bottom side with one side facing down in the paper feed tray 2 are in a state where one side faces up in the paper discharge tray 4. A so-called submerged paper discharge mechanism that is placed in order from the upper side is configured.

  The F sensor 13 is disposed on the paper feed tray 2 and is turned on when the document sheet SH is placed on the paper feed tray 2, and turned off when the document sheet SH is not placed on the paper feed tray 2. . The R sensor 14 is disposed at a detection position P2 between the conveyance roller 44 and the reading position P1 in the conveyance path 22, and is turned on when the original sheet SH passes the detection position P2 on the conveyance path 22, and the original sheet SH. Is turned off when it does not pass the detection position P2. That is, the R sensor 14 detects the document sheet SH that passes through the detection position P2.

  Further, the image reading apparatus 1 includes a power switch and various setting buttons, and includes an operation unit 11 that receives an operation command and the like from a user, and a display unit 12 that includes an LED and a liquid crystal display and displays the status of the image reading apparatus 1. Is provided.

2. Configuration of CIS and document holding member (CIS configuration)
As shown in FIG. 1, the CIS 30 includes a light emitting unit 31, a light guide 32, a light collector 33, and a light receiving unit 34. The light emitting unit 31 includes a plurality of light emitting diodes arranged in the main scanning direction H1 orthogonal to the transport direction H2. The light guide 32 is an optical member that guides light emitted from each light emitting diode of the light emitting unit 31 to the reading position P <b> 1 on the transport path 22. The condenser 33 is an optical member that guides the light reflected at the reading position P1 to the light receiving unit 34, and a plurality of light receiving lenses 35 are arranged in the main scanning direction H1. The light receiving unit 34 is configured by arranging a plurality of light receiving elements 37 (see FIG. 2) in the main scanning direction H1 on a light receiving substrate 36 (see FIG. 2).

  Here, FIG. 2 is a schematic view of the CIS 30 and the document pressing member 46 as viewed from the front. The reading area E where the CIS 30 reads an image extends along the main scanning direction H1 at the reading position P1, and the width W in the main scanning direction H1 is substantially equal to the total length of all the light receiving elements 37 arranged on the light receiving substrate 36. Are the same.

  The reading area E includes a passing area E1 and a side area E2 arranged in the main scanning direction H1. As shown in FIG. 7, the passage area E1 is an area through which the original sheet SH passes when the original sheet SH conveyed along the conveyance path 22 is not inclined, and its width in the main scanning direction H1. W1 is substantially the same as the document width of the document sheet SH. The side area E2 is located on both sides of the passage area E1 in the main scanning direction H1. The side area E2 is arranged adjacent to the passage area E1, and as shown in FIG. 7, when the original sheet SH conveyed along the conveyance path 22 is not inclined, the original sheet SH is Do not pass.

The side region E2 on the right side of the passage region E1 includes a first side region R1 and a second side region R2 aligned in the main scanning direction H1, and the side region E2 on the left side of the passage region E1 includes A first side region L1 and a second side region L2 arranged in the main scanning direction H1 are included. In each lateral region E2, the first lateral region R1 (L1) and the second lateral region R2 (L2) are arranged in this order from the passing region E1 side. That is, the first side regions R1 and L1 are arranged adjacent to the passage region E1, and the width W2 in the main scanning direction H1 is the document width W1 of the document sheet SH and the image processing unit 25 described later. It is determined as follows according to the limit inclination angle α (see FIG. 2). The image processing unit 25 is an example of a correction unit.
W2 = W1 × tanα

(Configuration of the document holding member)
The document pressing member 46 has a width in the main scanning direction H1 substantially the same as the width W of the reading area E. Therefore, the CIS 30 can read not only the image in the passage area E1 but also the image in the side area E2. Hereinafter, the entire image read by the CIS 30 in the reading area E is referred to as a read image G, and the entire image of the original sheet SH read in the passage area E1 is referred to as an original image G1, and is read in the side area E2. The image on the facing surface 46A of the original pressing member 46 is referred to as a side image G2. That is, the read image G includes one document image G1 corresponding to the passage area E1 and two side images G2 corresponding to the side areas E2 on both sides of the passage area E1. The read image G is an example of read data, and the side image G2 is an example of side area data.

  In addition, among the side images G2, the images of the facing surface 46A of the document pressing member 46 read by the CIS 30 in the first side regions R1 and L1 are referred to as first side images GR1 and GL1, which are the second side images. The images of the facing surface 46A of the document pressing member 46 read in the side areas R2 and L2 are referred to as second side images GR2 and GL2. The first side images GR1 and GL1 are examples of first side region data, and the second side images GR2 and GL2 are examples of second side region data. 7 to 9, the read image G and the side image G2 are described as a plurality of convex data sets corresponding to the plurality of light receiving lenses 35 included in the light collector 33.

  Each of the first lateral regions R1 and L1 and the second lateral regions R2 and L2 includes a plurality of light receiving elements 37. For example, the first lateral region R1 includes NRA light receiving elements 37. The first lateral region L1 includes NLA light receiving elements 37 (NRA, NLA: natural number of 2 or more). Therefore, each of the first side images GR1, GL1 and the second side images GR2, GL2 includes a plurality of pixel data. For example, the first side image GR1 is generated by NRA light receiving elements 37. The NRA pieces of pixel data are included, and the first side image GL1 includes NLA pieces of pixel data generated by the NLA light receiving elements 37. That is, NRA and NLA can be said to be the total number of pixel data included in the first side images GR1 and GL1.

  Further, as described above, the document pressing member 46 can be displaced in the vertical direction by the spring 48. For this reason, when the original sheet SH is in the facing Z between the CIS 30 and the original pressing member 46, the original pressing member 46 is displaced farther from the CIS 30 than when the original sheet SH is not in the opposing Z. Specifically, as shown in the upper part of FIG. 3, when there is no original sheet SH in the facing Z, the distance between the facing Z is D1. On the other hand, as shown in the middle and lower stages of FIG. 3, when the document sheet SH is located between the facing Z, the document pressing member 46 is pushed up against the elastic force of the spring 48 by the document sheet SH. The distance Z between the opposing surfaces is D2 (> D1).

  Further, when the document sheet SH is located between the facing Z, the document pressing member 46 is displaced to a position farther from the CIS 30 when the document sheet SH is thicker than when the document sheet SH is thin. Specifically, as shown in the middle part of FIG. 3, when the original sheet SH is normally present in the facing Z, the distance between the facing Z is D1. On the other hand, as shown in the lower part of FIG. 3, when the document sheet SH is bent in the facing Z and the jamming occurs, the document pressing member 46 is present when the overlapping sheets Z exist in the facing Z. Is pushed up further against the elastic force of the spring 48, the distance Z between the opposing faces becomes D3 (> D2).

  With the above configuration, the side image G2 becomes darker when the document sheet SH is present in the facing Z than in the case where the document sheet SH is not present in the facing Z. Further, the side image G2 becomes darker as the thickness of the original sheet SH existing between the facing Z is larger. For this reason, if the side image G2 when the original sheet SH is normally present between the opposing sides Z has the standard value, it can be determined that the original sheet SH has been bent and the jam has occurred.

  The document pressing member 46 has a facing surface 46A facing the CIS 30 that is white, for example, and has a reflectance higher than that of the white document sheet SH. As shown in the lower part of FIGS. 8 and 9, the side image G2 when the original sheet SH is present in the side region E2 has the original sheet SH in the facing Z as shown in the lower part of FIG. Moreover, it becomes darker than when the original sheet SH is not present in the side region E2. For this reason, if the original sheet SH exists between the facing Z and the side image G2 when the original sheet SH does not exist in the side area E2 has a standard value, the original sheet SH is present in the side area E2. Is present, that is, it can be determined that the original sheet SH is tilted. Then, by determining that the original sheet SH is inclined, it is possible to determine that the original sheet SH cannot pass through the conveyance path 22 and a jam has occurred.

3. As shown in FIG. 4, the image reading apparatus 1 includes a CPU 20, a ROM 26, a RAM 27, a device control unit 28, an analog front end (hereinafter referred to as AFE) 23, and a motor driver 24. The image processing unit 25 is connected to the operation unit 11, the display unit 12, the F sensor 13, the R sensor 14, and the like via a bus 29. As shown by a dotted line 21 in FIG. 3, the one including the CPU 20, the ROM 26, and the RAM 27 is an example of the control unit.

  Various programs for controlling the operation of the image reading apparatus 1 are stored in the ROM 26, and the CPU 20 controls each part according to the program read from the ROM 26 and executes an image reading process to be described later. The ROM 26 stores reference values K1 and K2, a reference time TK, which will be described later, and the total data numbers NRA and NLA.

  The device control unit 28 is connected to the CIS 30 and transmits a read control signal to the CIS 30 based on a command from the CPU 20. The CIS 30 reads the document sheet SH based on the reading control signal from the device control unit 28.

  The CIS 30 repeats reading at the reading position P1 of the conveyance path 22 when reading the original sheet SH conveyed on the conveyance path 22. The CIS 30 acquires a read image G that is a collection of pixel data generated by the light receiving elements 37 arranged in the main scanning direction H1 by one reading. The CIS 30 outputs the acquired unit reading data to the AFE 23.

  The AFE 23 is connected to the CIS 30 and converts an analog signal read image G output from the CIS 30 into a digital signal, that is, a gray scale data read image G, based on a command from the CPU 20. The AFE 23 stores the converted read image G in the RAM 27 via the bus 29. As the CIS 30 repeats reading, a plurality of read images G continuous in the sub-scanning direction are stored in the RAM 27.

  The motor driver 24 is connected to the motor M, generates a pulse signal based on a command from the CPU 20, and transmits the pulse signal to the motor M. The motor M is a well-known stepping motor, and is driven to rotate by one rotation angle by one pulse of a pulse signal. When the motor M is driven by one step, each roller constituting the conveyance unit 15 rotates by a predetermined angle, and the original sheet SH is conveyed on the conveyance path 22 by a predetermined distance. When the CPU 20 transports the document sheet SH, the CPU 20 transmits a pulse signal to the motor driver 24, and the transport unit 15 transports the document sheet SH by a distance obtained by multiplying the number of pulses of the pulse signal by a predetermined distance. . Hereinafter, the number of pulses of the pulse signal transmitted from the CPU 20 to the motor M is referred to as a step number.

  The image processing unit 25 performs various image processing on the read image G stored in the RAM 27 based on a command from the CPU 20. For example, as illustrated in FIG. 8, the document sheet SH is inclined. If it is, the inclination correction process for correcting the inclination of the read image G is executed. In the inclination correction process, the image processing unit 25 extracts edge pixel data from the read image G stored in the RAM 27, extracts a range corresponding to the original sheet SH in the read image G, and also extracts the range of the original sheet SH. Detect tilt. Then, a rotation process is executed based on the detected inclination of the original sheet SH to correct the inclination.

  The above limit inclination angle α means an upper limit angle at which the image processing unit 25 can perform the rotation process. When the detected inclination of the original sheet SH is equal to or greater than the limit inclination angle α, the image processing unit 25 may not be able to pass through the conveyance path 22 and the jam may occur. Therefore, the tilt correction process is not executed.

4). Reading Process Next, the reading process of the original sheet SH will be described with reference to FIGS. In the present embodiment, an example will be described in which one original sheet SH whose original lower surface facing the CIS 30 of the original sheet SH is white and plain is read.
As shown in FIG. 5, the CPU 20 confirms that the original sheet SH is placed on the paper feed tray 2 using the F sensor 13, and issues an image reading instruction for the original sheet SH from the user via the operation unit 11. Is input, the reading process is started. When the reading process is started, the CPU 20 sets a jam determination flag indicating that a jam has occurred to OFF (S2), and instructs the conveyance unit 15 to convey the original sheet SH (S4).

  Next, the CPU 20 monitors the position of the document sheet SH being conveyed using the R sensor 14 (S6: NO), and when the R sensor 14 is turned on (S6: YES), the detection position P2 on the conveyance path 22 is detected. It is detected that the leading edge of the original sheet SH in the transport direction H2 has reached. Further, the CPU 20 conveys the original sheet SH while the first step number ST1 is counted (S8), whereby the leading end of the original sheet SH in the conveying direction H2 is read position P1 as shown in FIG. Is reached, the CIS 30 is instructed to read once (S10).

  When the read image G is acquired by the reading, the CPU 20 uses the first side image GR1, GL1 of the read image G as the first side standard that is a standard value in the first side image GR1, GL1. The images are stored in the RAM 27 as images HR1 and HL1 (see FIG. 7). Further, the second side images GR2 and GL2 are stored in the RAM 27 as second side standard images HR2 and HL2 (see FIG. 7) which are standard values in the second side images GR2 and GL2 (S12). When the storage is completed, the CPU 20 starts measuring the elapsed time from the time when the storage is completed (S14).

  Next, the CPU 20 instructs the CIS 30 to perform one reading (S16). When the read image G is acquired by the reading, a jam detection process is executed (S18). The read image G in the following description of the jam detection process means the read image G acquired immediately before the jam detection process, and the read image G acquired in the process of S10 is the first side standard image. HR1, HL1 and second side standard images HR2, HL2 are shown.

(Jam detection process)
As shown in FIG. 6, when starting the jam detection process, the CPU 20 stores a start time T1, which is a time when the jam detection process is started, in the RAM 27 (S32). Next, the CPU 20 calculates an average value GRX2 (see FIG. 8) of a plurality of pixel data included in the second side image GR2 in the acquired read image G (S34). Similarly, an average value GLX2 (see FIG. 8) of a plurality of pixel data included in the second side image GL2 is calculated (S36).

  Next, the CPU 20 calculates an average value HRX1 (see FIG. 7) of the first side standard image HR1 stored in the RAM 27, and compares it with each pixel data included in the acquired first side image GR1. Then, among each pixel data included in the first side image GR1, a data number NR that is the number of different pixel data exceeding the second reference value K2 from the average value HRX1 is calculated (S38). The average value HRX1 is an example of a representative value, and the second reference value K2 is an example of a predetermined range.

  Similarly, the CPU 20 calculates an average value HLX1 (see FIG. 7) of the first side standard image HL1 stored in the RAM 27, and compares it with each pixel data included in the acquired first side image GL1. Then, among the pixel data included in the first side image GL1, a data number NL that is the number of different pixel data exceeding the second reference value K2 from the average value HLX1 is calculated (S40). When the CPU 20 calculates the average values GRX2, GLX2 and the number of data NR, NL, the CPU 20 stores the calculation end time T2, which is the time at which the calculation ends, in the RAM 27 (S42). The average value HLX1 is another example of the representative value.

  Next, the CPU 20 calculates the average value HRX2 (see FIG. 7) of the second side standard image HR2 stored in the RAM 27 and compares it with the average value GRX2 (see FIG. 8) of the second side image GR2. The CPU 20 checks whether or not a difference value obtained by subtracting the average value GRX2 of the second side image GR2 from the average value HRX2 of the second side standard image HR2 is larger than the first reference value K1. Further, the CPU 20 calculates the average value HLX2 (see FIG. 8) of the second side standard image HL2 stored in the RAM 27, and compares it with the average value HLX2 of the second side standard image HL2. The CPU 20 checks whether or not the difference value obtained by subtracting the average value GLX2 of the second side image GL2 from the average value HLX2 of the second side standard image HL2 is larger than the first reference value K1 (S44). The first reference value K1 is another example of the predetermined range.

  When the CPU 20 detects that at least one of the difference values is larger than the first reference value K1 (S44: YES), the CPU 20 sets a jam determination flag to ON (S50) and ends the jam detection process. On the other hand, when the CPU 20 detects that any of the difference values is equal to or less than the first reference value K1 (S44: NO), next, the number of data NR, NL and the total number of data NRA of the first side images GR1, GL1. Compare with NLA.

  The CPU 20 confirms whether the data number NR is equal to the total data number NRA of the first side image GR1, and confirms whether the data number NL is equal to the total data number NLA of the first side image GL1. (S46). When the CPU 20 detects that at least one of the data numbers NR and NL is equal to the corresponding total data numbers NRA and NLA (S46: YES), the CPU 20 sets the jam determination flag to ON (S50) and ends the jam detection process. .

  On the other hand, if the CPU 20 detects that any of the data numbers NR and NL is smaller than the corresponding total data numbers NRA and NLA (S46: NO), then the calculation end time T2 and the start time T1 stored in the RAM 27 are determined. Evaluate the elapsed time between. The CPU 20 checks whether or not the difference time obtained by subtracting the calculation end time T2 from the start time T1 is longer than the reference time TK (S48). If the difference time is longer than the reference time TK (S48: YES), The jam determination flag is set to ON (S50), and the jam detection process is terminated. On the other hand, if the difference time is equal to or shorter than the reference time TK (S48: NO), the jam detection process is terminated without setting the jam determination flag on, that is, with the jam determination flag set to off.

  When the CPU 20 completes the jam detection process, the CPU 20 returns to the reading process shown in FIG. 5 and checks the state of the jam determination flag (S20). When the jam determination flag is set to OFF (S20: NO), the CPU 20 determines that no jam has occurred. In this case, the CPU 20 confirms the state of the R sensor 14 (S22). If the R sensor 14 is turned on, or the R sensor 14 is turned off, the first time after the R sensor 14 is turned off. When the step number ST1 is not counted (S22: NO), the original sheet SH is conveyed by one step, and the processing from S16 is repeated.

  The CPU 20 causes the CIS 30 to read the original sheet SH by repeating the processing from S16 to S22. Therefore, it can be said that the CPU 20 is performing jam detection processing while reading the original sheet SH. On the other hand, when the R sensor 14 is turned off and the first step number ST1 is counted after the R sensor 14 is turned off (S22: YES), the CPU 20 further determines the second step number ST2, the original sheet SH. , And the document sheet SH is discharged to the discharge tray 4. Then, the CPU 20 instructs the conveyance unit 15 to end conveyance of the original sheet SH (S24), and ends the reading process.

  On the other hand, when the jam determination flag is set to ON (S20: YES), the CPU 20 determines that a jam has occurred. In this case, the CPU 20 immediately instructs the conveyance unit 15 to stop conveying the original sheet SH (S26), and the original sheet is further conveyed and a jam occurs or the original is bent due to the occurrence of the jam. The sheet SH is further prevented from being bent. The CPU 20 displays an error message on the generated display unit 12, notifies the user of the occurrence of the error (S28), and ends the reading process.

5. Advantages of the present embodiment (1) In the image reading apparatus 1 of the present embodiment, in addition to the passage area E1 through which the document sheet SH passes, the side located on the side of the passage area E1 in the reading area E of the CIS 30. Region E2 is included. When the original sheet SH is read using the CIS 30, the original read in the side area E2 at the time when the leading end in the transport direction H2 of the original sheet SH reaches the reading position P1 prior to reading the original sheet SH. A side image G2 of the facing surface 46A of the pressing member 46 is acquired.

  When the leading edge of the document sheet SH reaches the reading position P1, the leading edge of the document sheet SH enters the space Z between the CIS 30 and the document pressing member 46, and the distance between the facing Z becomes D2. As shown in FIG. 7, when the document sheet SH is not tilted, the side image G2 does not include the image of the document sheet SH. Even when the original sheet SH is inclined, as indicated by a dotted line 54 in FIGS. 8 and 9, when the leading edge of the original sheet SH reaches the reading position P1, the image of the original sheet SH is displayed on the side image G2. Not included. Therefore, the side image G2 at the time when the leading edge of the document sheet SH reaches the reading position P1 is an image in which the distance Z between the facing portions is D2 and the image of the document sheet SH is not included. In the image reading apparatus 1 of the present embodiment, this side image G2 is stored as a standard side image G2.

  When the original sheet SH is read using the CIS 30, the side image G2 corresponding to the side area E2 is read, and compared with the standard side image G2, a jam occurs in the original sheet SH. Judge that there is. According to the image reading apparatus 1, it is possible to determine during the reading of the original sheet SH that a jam has occurred in the original sheet SH by using the side image G2 acquired when the original sheet SH is read. It is possible to judge the occurrence of jam earlier than before.

(2) Specifically, when a jam occurs in the original sheet and the original sheet SH is folded and present in the opposite space Z, the side image G2 has the original pressing member 46 compared to the standard side image G2 in the CIS 30. Since it was acquired when it exists in a position far from the distance, it becomes dark. In the image reading apparatus 1 of the present embodiment, by utilizing this, the second side images GR2 and GL2 corresponding to the second side regions R2 and L2 of the side images G2 are the standard second side. The occurrence of a jam can be determined when the second side standard images HR2 and HL2, which are the side images GR2 and GL2, are reduced beyond the first reference value K1.

  Note that the second side regions R2 and L2 are separated from the passage region E1 via the first side regions R1 and L1, and there is a low possibility that the original sheet SH enters as shown in FIG. Further, as shown in FIG. 9, even if the original sheet SH enters, there is little. Therefore, the first side region corresponding to the first side regions R1, L1 is determined by determining the distance between the facing Z using the second side images GR2, GL2 corresponding to the second side regions R2, L2. Compared with the case where the images GR1 and GL1 are used, the influence of the original sheet SH can be suppressed and the distance between the facing Z can be accurately determined.

(3) As described above, when the original sheet SH exists in the side area E2, the side image G2 is the standard image even when the original sheet SH is jammed and the original sheet SH is not folded and exists between the facing Z. It becomes darker than the side image G2. In the image reading apparatus 1 of the present embodiment, using this, the first side images GR1, GL1 corresponding to the first side regions R1, L1 of the side image G2 are the standard first side. The occurrence of a jam can be determined when the first side standard images HR1 and HL1, which are the side images GR1 and GL1, have decreased beyond the second reference value K2.

  More specifically, when the first side images GR1 and GL1 are composed of a plurality of pixel data, the original sheet SH is compared with the first side standard images HR1 and HL1 for each pixel data. It can be judged how much it is tilted. That is, when the first side images GR1 and GL1 shown in FIG. 9 are acquired, more pixel data is stored on the first side than when the first side images GR1 and GL1 shown in FIG. 8 are acquired. Since the standard images HR1 and HL1 are lower than the second reference value K2, it can be determined that the inclination of the original sheet SH is large.

  Furthermore, in the image reading apparatus 1 of the present embodiment, the width of the first side images GR1 and GL1 in the main scanning direction H1 is set based on the limit inclination angle α of the image processing unit 25. Therefore, as shown in FIG. 9, when all the pixel data included in the first side image GL1 has dropped from the first side standard image HL1 beyond the second reference value K2, the original sheet SH is tilted at the limit. It is determined that the vehicle is inclined beyond the angle α. Thereby, it is possible to prevent the reading of the original sheet SH tilting beyond the range in which the tilt correction by the image processing unit 25 can be continued.

(4) In the image reading apparatus 1 of the present embodiment, the side area E2 is provided on both sides of the passage area E1. When it is determined that a jam has occurred in the original sheet SH, the occurrence of a jam is determined when the side image G2 in at least one side region E2 satisfies a predetermined condition. Therefore, compared with the case where the side area E2 is provided on one side of the passage area E1, the occurrence of jam can be accurately determined.

<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.
(1) In the above embodiment, the image reading apparatus 1 having the scanner function has been described. However, the present invention is not limited to this, and the present invention is a multifunction device having a printer function, a copy function, a facsimile function, and the like. May be.

(2) In the above-described embodiment, the image reading apparatus 1 has one CPU 20, and an example in which various processes such as an image reading process are executed by the one CPU 20 has been described. Not limited to. For example, if each unit may be configured by a plurality of CPUs, each unit may be configured only by a hardware circuit such as an ASIC (Application Specific Integrated Circuit). Furthermore, each part may be comprised by one or several CPU and ASIC.

(3) Further, the program executed by the CPU 20 does not necessarily have to be stored in the ROM 26, and may be stored in the CPU 20 itself or in another storage device.

(4) In the above embodiment, the description has been given using the example in which the side region E2 is provided on both sides of the passage region E1, but the side region E2 may be provided only on one side.

(5) In the above embodiment, the description has been given using the example in which the jam caused by the folding of the original sheet SH and the jam caused by the inclination of the original sheet SH are determined in this order. The jam caused by the inclination of the original sheet SH may be determined after the jam caused by the inclination is determined. Further, only one of the determinations may be made. If only one of the determinations is made, the side region E2 may not include different regions such as the first side regions R1, L1 and the second side regions R2, L2.

(6) In the above embodiment, the document pressing member 46 has been described using an example in which the document pressing member 46 can be displaced in the vertical direction by the spring 48. However, the present invention is not limited to this. When the document pressing member 46 is configured so as not to be displaced in the vertical direction, the folded document sheet SH hardly enters the facing Z, but the folded document sheet SH enters the facing Z due to the deformation of the document pressing member 46 itself. Can do. In this case, elasticity due to deformation occurs in the document pressing member 46, and the document pressing member 46 also serves as a displacement portion. Therefore, the spring 48 is not always necessary.

22: transport path, 30: CIS, 46: document pressing member, 48: spring, E: reading area, E1: passage area, E2: side area, R1, L1: first side area, R2, L2: first 2 side regions, G: scanned image, G1: document image, G2: side image, GR1, GL1: first side image, GR2, RL2: second side image, GRX2, RLX2: second side image HR1, HL1: first side standard image, HRX1, HLX1: average value of the first side standard image, HR2, HL2: second side standard image, HRX2, HLX2: second side standard image Average value, W1: document width, Z: facing distance, α: limit inclination angle

Claims (5)

A moving unit that moves the document sheet with respect to a predetermined reading position;
In the reading position, an image is read in a reading region along a main scanning direction orthogonal to the moving direction of the moving unit, and an image reading unit including a passing region and a side region located to the side of the passing region When,
An opposing member disposed opposite to the image reading unit over the reading area;
A control unit;
With
The controller is
A data acquisition process for causing the image reading unit to read when the original sheet reaches the reading position, and acquiring side area data obtained by reading the facing member corresponding to the side area;
A reading process for causing the image reading unit to read the original sheet after the data acquisition process;
During the reading process, when the value of the side area data acquired in the data acquisition process and the value of the side area data acquired in the reading process differ beyond a predetermined range, A determination process for determining that a jam has occurred in the original sheet;
An image reading apparatus that executes The image reading apparatus according to claim 1,
Furthermore,
Displacement that displaces the opposing member to a position farther from the image reading unit when the thickness of the original sheet between the image reading unit and the opposing member is thicker than when the original sheet is thin. Part,
With
The controller is
In the determination process, when the value of the side area data acquired in the reading process falls below the first reference value compared to the value of the side area data acquired in the data acquisition process An image reading apparatus that determines that a jam has occurred in the original sheet. The image reading apparatus according to claim 2,
Furthermore,
A correction unit that performs inclination correction on the read data obtained by the image reading unit reading the original sheet;
Each of the lateral regions is adjacent to the passing region and has a width in the main scanning direction that is determined based on a limit inclination angle that can be corrected by the correction unit, and the first lateral region A second lateral region located outside the region,
The controller is
In the data acquisition process and the reading process, side area data corresponding to the first side area, the first side area data including a plurality of pixel data, and the second side area And corresponding second side area data,
In the determination process, the value of the second side area data acquired in the reading process is greater than the value of the second side area data acquired in the data acquisition process. If it falls over, it is determined that a jam has occurred on the original sheet,
Furthermore,
The value of the second side area data acquired in the reading process is lower than the first reference value compared to the value of the second side area data acquired in the data acquisition process. Even if not, all of the pixel data constituting the first side area data acquired in the reading process and the first side area data acquired in the data acquisition process An image reading apparatus that determines that a jam has occurred in the original sheet when a representative value of pixel data differs beyond a second reference value. An image reading apparatus according to any one of claims 1 to 3,
The lateral region is provided on both sides of the passing region,
The controller is
In the data acquisition process and the reading process, the side area data is acquired for each side area,
In the determination process, for each side area, the value of the side area data acquired in the data acquisition process is compared with the value of the side area data acquired in the reading process, and at least In one of the side areas, the value of the side area data acquired in the data acquisition process is different from the value of the side area data acquired in the reading process beyond a predetermined range. An image reading apparatus that determines that a jam has occurred in the original sheet. An image reading apparatus according to any one of claims 1 to 4,
The controller is
An image reading apparatus that further executes a stop process for stopping the movement of the original sheet when it is determined in the determination process that a jam has occurred in the original sheet.

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