JP5471945B2 - Paper transport device and image reading device - Google Patents

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet placed on a sheet feeding tray, and an image reading apparatus that includes the sheet conveying apparatus and reads an image of a sheet conveyed to the sheet conveying apparatus. The present invention relates to a sheet conveying apparatus and an image reading apparatus capable of suppressing erroneous conveyance of a sheet of a size that cannot be conveyed.

  2. Description of the Related Art Conventionally, various devices such as an image reading apparatus and an image forming apparatus are provided with a sheet conveying apparatus that conveys a sheet placed on a paper feed tray, and image reading and image forming are performed on the sheet conveyed by the sheet conveying apparatus. Etc. have been made.

  In this type of paper transport device, a placement sensor that detects that a paper is placed on the paper feed tray is provided. When the placement sensor detects the paper, the paper is transported on the transport path by a plurality of rollers. In this type of paper transport apparatus, paper having a paper size whose length in the paper transport direction is shorter than the longest distance along the transport path between the rollers cannot be transported.

  Further, in this type of paper transport apparatus, a paper size detection sensor for detecting the paper size is separately provided in order to suppress transport of paper of a paper size that cannot be transported. For example, a configuration has been proposed in which a number of alignment members that are folded by the weight of the sheet are arranged in the main scanning direction and the size of the sheet is detected based on which alignment member is folded (for example, Patent Document 1). reference).

Japanese Patent Laid-Open No. 2003-238017

  However, if a paper size detection sensor is separately provided as in Patent Document 1, the manufacturing cost of the apparatus is increased. However, if the paper size detection sensor is not provided, when the placement sensor detects the paper, the paper of the paper size that cannot be transported by the paper transport device is transported, causing a problem that the paper is jammed.

  Accordingly, the present invention provides a paper transport device capable of suppressing erroneous transport of paper of a paper size that cannot be transported without providing a paper size detection sensor, and an image reading apparatus including the paper transport device Was made for the purpose of providing.

  The paper transport device of the present invention made to achieve the above object has rollers arranged at a plurality of locations along the transport path, and transports the paper placed on the paper feed tray along the transport path. A transport unit; a first sensor that detects paper transported by the transport unit; and a second sensor that is disposed downstream of the first sensor and detects paper transported by the transport unit. The section is capable of transporting a sheet having a length in the transport direction of the sheet that is longer than a longest interval along the transport path between the rollers in a main scanning direction orthogonal to the transport direction. The first sensor and the second sensor are arranged such that the interval between the first sensor and the second sensor is longer than the width in the main scanning direction of a standard paper size that cannot be transported by the transport unit. Are arranged, and After the first sensor detects a sheet, a first predetermined time set longer than the time required for the sheet to be transported by the transport unit and reach the position detected by the second sensor has elapsed. Further, when the second sensor does not detect a sheet, a control unit is provided that stops conveyance of the sheet by the conveyance unit.

  In the paper transport device of the present invention configured as described above, the transport unit has rollers arranged at a plurality of locations along the transport path, and the paper placed on the paper feed tray is moved along the transport path. Transport. The first sensor detects a sheet conveyed by the conveying unit, and the second sensor detects a sheet conveyed by the conveying unit downstream from the first sensor.

  Here, since the transport unit transports the sheet via rollers arranged at a plurality of locations along the transport path, the length in the transport direction is shorter than the longest interval along the transport path between the rollers. The sheet is a sheet that cannot be transported by the transport unit. Therefore, in the present invention, the distance between the first sensor and the second sensor in the main scanning direction orthogonal to the transport direction is such that the regular paper size that cannot be transported by the transport unit is in the main scanning direction. The first sensor and the second sensor are arranged so as to be longer than the width. For this reason, a sheet of a standard paper size that cannot be transported is not detected by both the first sensor and the second sensor during transport by the transport unit.

  Therefore, when the second sensor does not detect the sheet even after the first predetermined time has elapsed after the first sensor detects the sheet during conveyance of the sheet, the control unit conveys the sheet by the conveyance unit. Stop. The first predetermined time is set longer than the time required for the paper to be transported by the transport unit and reach the position detected by the second sensor after the first sensor detects the paper. It was time. For this reason, according to the present invention, it is possible to prevent a paper having a paper size that cannot be conveyed from being erroneously conveyed.

  In addition, the first sensor and the second sensor detect paper at locations displaced upstream and downstream on the transport path, and thus providing sensors at a plurality of locations as described above is generally performed in conventional apparatuses. Yes. In other words, according to the present invention, since the positions of the first sensor and the second sensor in the conventional apparatus in the main scanning direction are devised, it is possible to suppress the conveyance of the paper that cannot be conveyed without adding a special configuration. Further, it is possible to suppress erroneous conveyance of a paper having a size that cannot be conveyed without providing a paper size detection sensor.

  The interval between the first sensor and the second sensor in the main scanning direction orthogonal to the transport direction is shorter than the width in the main scan direction of a standard paper size that can be transported by the transport unit. In addition, the first sensor and the second sensor may be arranged respectively. As described above, the interval between the first sensor and the second sensor in the main scanning direction orthogonal to the transport direction is shorter than the width in the main scan direction of the standard paper size that can be transported by the transport unit. If configured, a sheet of a standard sheet size that can be conveyed can be detected by both the first sensor and the second sensor.

  In addition, a third sensor that detects a sheet on the transport path downstream from the second sensor is further provided, and the control unit detects the sheet after the second sensor detects the sheet, and then the third sensor detects the sheet. Even when the second sensor stops detecting the paper before detecting the paper, the transport of the paper by the transport unit may be stopped.

  In this case, even if the standard paper that cannot be transported is detected by both the first sensor and the second sensor as being skewed, the paper transport can be stopped as follows. In other words, even if a regular sheet that cannot be conveyed by skew is detected by both the first sensor and the second sensor, the detection by the second sensor is temporary. In that case, after the second sensor detects the sheet, the second sensor detects the sheet until the third sensor that detects the sheet on the transport path on the downstream side of the second sensor detects the sheet. It will not be detected. Therefore, the control unit stops the conveyance of the sheet by the conveyance unit even in such a case. Therefore, in this case, it is possible to more effectively suppress the paper having a paper size that cannot be conveyed by mistake.

  In this case, the apparatus further includes a cover that covers a part of the transport path so as to be openable and closable, wherein the first sensor detects a sheet placed on the sheet feeding tray, and the first predetermined time May be the time required from when the sheet is conveyed from the sheet feeding tray to when the part of the conveying path is conveyed by the conveying unit. In this case, the conveyance of the fixed-size paper that cannot be conveyed is stopped while the sheet is conveyed along the part of the conveyance path. Then, the paper whose conveyance is stopped at the part of the conveyance path can be easily removed by opening a cover that covers the part so as to be opened and closed. Accordingly, in this case, it becomes easy to remove a sheet of a size that cannot be transported from the transport path.

  In that case, an interval along the transport direction of the plurality of rollers in the part of the transport path is configured to be shorter than a length in the transport direction of a sheet of a standard paper size that cannot be transported. An interval along the conveyance direction of at least two of the rollers in the conveyance path on the downstream side of the section may be the longest interval.

  Further, in that case, the standard-sized paper that cannot be transported by the transport unit has a length in the main scanning direction in which the length of the paper of the non-standard-sized paper size is perpendicular to the transport direction. The length in the transport direction of the paper of the impossible standard paper size that is shorter than the interval between the first sensor and the second sensor is shorter than the longest interval, and in the part of the transport path. Business card size paper longer than the interval between the plurality of rollers may be used. In this case, it is possible to prevent the business card size paper that cannot be conveyed from being conveyed.

  In addition, an image reading apparatus according to the present invention includes any one of the above-described sheet conveyance devices and an image reading unit that reads an image on at least one surface of the sheet conveyed along the conveyance path. For this reason, in the image reading apparatus of the present invention, an image on at least one side of the sheet conveyed along the conveyance path can be read via the image reading unit.

  According to another aspect of the present invention, there is provided an image reading apparatus configured to read an image on one side of a sheet transported on the transport path downstream of the second sensor of the transport path and the sheet transport apparatus including the cover. A first image reading unit; and a second image reading unit that reads an image on the other side of the sheet conveyed on the conveyance path downstream of the first image reading unit and the third sensor in the conveyance path. The second sensor detects that the sheet has reached the reading position of the first image reading unit, and the third sensor detects that the sheet has reached the reading position of the second image reading unit. It may be characterized by that.

  In this case, the second sensor detects that the sheet has reached the reading position on one side by the first image reading unit, and the third sensor detects the other side of the sheet by the second image reading unit. It is detected that the reading position is reached. Also, providing such a sensor means that the first image reading unit that reads an image on one side of the sheet conveyed along the conveyance path, and the conveyance on the downstream side of the first image reading unit in the conveyance path. The image reading apparatus generally includes a second image reading unit that reads an image on the other side of the sheet conveyed along the path. Therefore, in the image reading apparatus of the present invention, the configuration is hardly complicated as compared with the conventional apparatus, and an increase in manufacturing cost can be suppressed.

1 is a perspective view schematically illustrating a configuration of a multifunction machine to which the present invention is applied. FIG. 2 is a cross-sectional view schematically illustrating a configuration of a main part of an image reading apparatus mounted on the multifunction machine. FIG. 2 is a perspective view illustrating the configuration of the image reading apparatus with an ADF cover opened. 3 is a plan view illustrating a configuration of a main part in the vicinity of a paper feed roller of the image reading apparatus. FIG. It is a block diagram showing the structure of the control system of the image reading apparatus. It is a flowchart showing the single-sided reading process performed with the control system. It is a top view showing a part of principle of the single-sided reading process. It is a flowchart showing the double-sided reading process performed with the said control system. It is a flowchart showing the continuation of the double-sided reading process.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view schematically showing the configuration of a multifunction machine 1 to which the present invention is applied. FIG. 2 is a schematic diagram showing the configuration of the main part of an image reading apparatus 10 mounted on the multifunction machine 1. It is sectional drawing to represent. As shown in FIG. 1, the multifunction machine 1 includes a document cover 30 that can be opened and closed on the upper surface of the base body 20.

[Entire configuration of image reading apparatus]
As shown in FIG. 1, on the upper end surface of the substrate 20, a transparent glass platen on which a paper sheet is placed when the image reading apparatus 10 of the present embodiment is used as a flatbed scanner. 21 is provided. Then, the document cover 30 is closed on the surface of the document table 21 so as to cover the paper placed on the document table 21, so that one side of the upper end surface of the base 20 (the back side in FIG. The side of the side is also referred to as the rear side) and is attached to be freely opened and closed via a hinge 31.

  Further, as shown in FIG. 2, the document cover 30 is configured as a document cover having an ADF (Automatic Document Feeder), and conveys the paper placed on the paper feed tray 110 in the sub-scanning direction along the conveyance path. The first reading device 210 as an example of the first image reading unit capable of performing image reading on the back surface (an example of one surface) of the paper transported along the transport path, and the transport unit 100 functioning as an ADF. And. A second reading device 230 (an example of a second image reading unit) capable of reading an image on the surface of the paper (an example of the other side) in parallel with the first reading device 210 is provided on the base body 20. It has been. Further, a portion of the image reading apparatus 10 excluding the first reading device 210 and the second reading device 230 (both examples of an image reading unit) corresponds to the paper conveying apparatus of the present invention.

  The transport unit 100 includes various rollers 121 to 129 that transport a sheet (original) placed on the paper feed tray 110 to the paper discharge tray 130 along a transport path (dotted line in FIG. 2). The most upstream paper feed rollers 121 and 122 for feeding the paper placed on the paper feed tray 110 are held by a holder 133. When a plurality of papers are placed on the paper feed tray 110, the plurality of paper feed rollers 121 and 122 are arranged. A sheet of paper can be continuously fed one by one. The paper fed by the paper feed rollers 121 and 122 is transported sequentially through the nip portion of the transport rollers 123 and 124, the nip portion of the transport rollers 125 and 126, and the nip portion of the transport rollers 126 and 127, and finally The paper is discharged onto the paper discharge tray 130 by the paper discharge rollers 128 and 129.

  Further, in this transport path, the upstream side reading position is between the nip portion of the transport rollers 123 and 124 and the nip portion of the transport rollers 125 and 126, and the nip portion of the transport rollers 126 and 127 and the discharge rollers 128 and 129. The downstream reading position is set between each of the nip portions. The first reading device 210 for reading an image on the back side of the paper is provided corresponding to the upstream reading position, and further, the paper passing through the upstream reading position is provided on the reading surface of the first reading device 210. A back side document presser 220 to be pressed is provided. Further, the second reading device 230 for reading an image on the surface of the paper provided on the document table 21 is configured to be movable to a position corresponding to the downstream reading position, and passes through the downstream reading position. A front document holder 240 that presses the sheet against the reading surface of the second reading device 230 is provided.

  Further, on the conveyance path, a front sensor 310 as an example of a first sensor and a rear B sensor 320 as an example of a second sensor are used as sensors for detecting the presence or absence of a sheet being conveyed at a corresponding position. And a rear sensor 330 as an example of a third sensor. The front sensor 310 is a contact type sensor for detecting the paper placed on the paper feed tray 110, and the rear B sensor 320 and the rear sensor 330 are used for the first reading device 210 and the second reading device, respectively. 230 is a contact type sensor for detecting that the reading position 230 has been reached. Needless to say, these sensors may be replaced with optical sensors or the like.

  The second reading device 230 is fixed to an endless belt 357 provided between a driving pulley 353 that is rotationally driven by a motor 351 and a driven pulley (not shown), and the document table is rotated according to the rotation of the motor 351. 21 can be moved in the sub-scanning direction (left-right direction).

  Further, the document cover 30 includes an ADF cover 30A as an example of a cover that covers a part of the transport path (a path from the upper left end of the paper feed tray 110 to the top of the transport roller 126) so as to be opened and closed. . FIG. 3 is a perspective view showing the configuration of the document cover 30 with the ADF cover 30A opened. As shown in FIG. 3, when the ADF cover 30 </ b> A is opened, the transport path from the paper feed tray 110 to the transport roller 126 and the first reading device 210 are exposed above the document cover 30.

  FIG. 4 is a plan view showing the positional relationship between the main parts near the paper feed rollers 121 and 122 in the exposed portion. As shown in FIG. 4, the front sensor 310 projects on the paper feed tray 110 from the front side of the holder 133 that holds the paper feed rollers 121 and 122 (see FIG. 2). The protruding position of the front sensor 310 is 44.1 mm away from the center line of the paper feed tray 110 (the center line along the sub-scanning direction, that is, the sheet conveying direction) in the main scanning direction. Further, the rear B sensor 320 protrudes rearward on the downstream side of the conveying roller 124, and the protruding position is 58.25 mm away from the center line of the paper feed tray 110 rearward in the main scanning direction. Therefore, as indicated by a two-dot chain line in FIG. 4, a paper that is too small and difficult to be transported by the transport unit 100 such as the business card M is sandwiched between the paper feed tray 110 and the paper feed rollers 121 and 122. The case can be detected as follows.

  That is, among the intervals in the conveyance direction of the nip portions of the various rollers 121 to 129, the longest interval between the nip portions of the conveyance rollers 126 and 127 and the nip portions of the paper discharge rollers 128 and 129 is 136.2 mm. . Tables 1 and 2 list the lengths in the main scanning direction and the sub-scanning direction of A4 size, A5 size, and business card size as typical standard paper. Among the papers shown in Table 1, the A4 size and A5 size are both vertically and horizontally placed, and the length in the sub-scanning direction is longer than 136.2 mm. In both of the vertical placement and the horizontal placement, the length in the sub-scanning direction is shorter than 136.2 mm, so that the conveyance is impossible. In addition, the space | interval of the other adjacent nip part of the rollers 121-127 is shorter than the short side 60mm of a business card size.

  As described above, the position in the main scanning direction in which the rear B sensor 320 detects the sheet is spaced by 102.35 mm in the main scanning direction with respect to the position in the main scanning direction in which the front sensor 310 detects the sheet. Has been placed. As shown in Tables 1 and 2 above, this interval is wider than the length in the main scanning direction of the business card size as paper that cannot be transported by the transport unit 100 (predetermined standard paper). It is shorter than the length in the main scanning direction of A4 and A5 sizes as a sheet that can be transported by the section 100 (predetermined standard sheet). For this reason, in the image reading apparatus 10 of the present embodiment, it is possible to determine whether or not the sheet can be transported by the transport unit 100 as follows before the sheet actually becomes untransportable. it can. Hereinafter, the processing will be described.

[Configuration of control system of image reading apparatus]
FIG. 5 is a block diagram illustrating a configuration of a control system of the image reading apparatus 10. As shown in FIG. 5, the control system is configured with an ASIC 400 (an example of a control unit) as the center, and the ASIC 400 sends a control signal ADF to the first reading device 210 (ADF side CIS) and a second reading device 230 ( A device control unit 410 that outputs control signals FB to the FB side CIS) is provided. The first reading device 210 and the second reading device 230 output an analog read signal from the analog output terminal AO according to the control signals ADF and FB.

  In addition to the device control unit 410, the ASIC 400 includes a CPU 420, a ROM 430, a RAM 440, an NVRAM 450, an interface (I / F) 460 for the first reading device 210, an interface (I / F) 470 for the second reading device 230, an image. A processing unit 480 is provided. These units are connected to each other via a bus 490. A read signal output from the first reading device 210 is converted into digital data via the AFE 510 provided outside the ASIC 400, and then input to the interface 460 and processed by the image processing unit 480. Similarly, a read signal output from the second reading device 230 is converted into digital data via the AFE 530 provided outside the ASIC 400, input to the interface 470, and processed by the image processing unit 480.

  Further, the above-described motor 351 is connected to the bus 490 of the ASIC 400 via the drive circuit 540, and the motor 550 that drives the various rollers 121 to 129 of the transport unit 100 is connected via the drive circuit 560. Further, although not shown in FIG. 5, the ASIC 400 is also connected to the operation panel 600 (see FIG. 1) provided on the surface of the housing of the multifunction device 1 and the various sensors 310 to 330 (see FIG. 2). ing. Note that the operation panel 600 has an input unit such as a switch and a display unit.

[Processing in the above control system (single-sided reading process)]
Next, FIG. 6 is a flowchart showing a single-sided reading process executed by the CPU 420 of the ASIC 400 based on a program stored in the ROM 430. This process is started when the one-side reading is instructed via the operation panel 600.

  As shown in FIG. 6, in this process, first, in S1 (S represents a step: the same applies hereinafter), it is determined whether or not the start switch of the operation panel 600 has been pressed. If the start switch is not pressed (S1: N), the process waits as it is, and if the start switch is pressed (S1: Y), the process proceeds to S2. In S2, it is determined whether or not the front sensor 310 is ON. If the front sensor 310 is not ON (S2: N), the FB reading process is executed in S3, and the process ends. This FB reading process is a well-known process in which an image of a document (paper) placed on the document table 21 is read by driving a motor 351 through a drive circuit 540.

  On the other hand, if it is determined in S2 that the front sensor 310 is ON (S2: Y), the process proceeds to S4, and the motor 550 is driven via the drive circuit 560, thereby feeding paper. The conveyance of the paper placed on the tray 110 is started. In subsequent S5, it is determined whether or not the first predetermined time has elapsed since the start of conveyance in S4. If not (S5: N), whether or not the rear B sensor 320 is ON in S6. Is judged. Here, the first predetermined time is slightly longer than the time required for the sheet placed at the position where the front sensor 310 is turned on to be carried by the carrying unit 100 and the rear B sensor 320 is turned on, and The time is set such that the sheet does not pass through the nip portions of the transport rollers 125 and 126. For this reason, immediately after the sheet conveyance is started in S4, the loop processing in S5 and S6 is repeatedly executed.

  When a paper that is too small and cannot be transported by the transport unit 100 is transported as in the business card M described above, the front sensor 310 is turned ON (S2: Y), and transport is started. (S4), the rear B sensor 320 is not turned ON. Accordingly, in this case, before the rear B sensor 320 is turned on (S6: N), the first predetermined time elapses (S5: Y), jam processing is executed in S7, and the processing is terminated. The jam process is a process in which the conveyance of the sheet by the conveyance unit 100 is stopped and an indication that a jam (paper jam) has occurred is displayed on the operation panel 600. As described above, since the first predetermined time is set to a time during which the paper does not pass through the nip portions of the transport rollers 125 and 126, the paper whose transport has been stopped by the jam processing is placed on the ADF cover 30A. It can be easily removed by opening.

  On the other hand, when a sheet that can be transported by the transport unit 100 such as A4 size or A5 size is transported, the rear B sensor 320 is turned on (S6: N) before the first predetermined time has elapsed (S5: N). : Y), the process proceeds to S11. In S11, it is determined whether or not the rear B sensor 320 is turned off. If not (S11: N), a second predetermined time after the rear B sensor 320 is turned on in S12. It is determined whether or not elapses. If the second predetermined time has not elapsed (S12: N), it is determined in S13 whether or not the rear sensor 330 is ON. Here, the second predetermined time is set to be slightly longer than the time required for the sheet placed at the position where the rear B sensor 320 is turned on to be carried by the carrying unit 100 and the rear sensor 330 is turned on. . For this reason, immediately after the rear B sensor 320 is turned on, the loop processing of S11, S12, and S13 is repeatedly executed.

  Here, when a paper that is too small and cannot be transported by the transport unit 100, such as the business card M described above, is skewed and transported as illustrated in FIG. 7, the front sensor 310 and the rear B sensor 320. May be turned on (S6: Y). However, in such a case, the rear B sensor 320 is temporarily turned on. Therefore, in such a case, before the rear sensor 330 is turned on (S13: N), the rear B sensor 320 is turned off (S11: Y), and the process proceeds to S7 described above.

  For this reason, in this process, even when a paper that cannot be transported is skewed and transported, the jam processing (S7) is executed and the transport of the paper is stopped. The position in the main scanning direction where the rear sensor 330 detects the paper is between the position in the main scanning direction where the front sensor 310 detects the paper and the position in the main scanning direction where the rear B sensor 320 detects the paper. The position in the sub-scanning direction where the rear sensor 330 detects the paper is the position where the rear B sensor 320 is turned off before the rear sensor 330 is turned on when the business card M is conveyed obliquely as described above. It is arranged. Further, the width in the main scanning direction is wider than the distance between the front sensor 310 and the rear B sensor 320, and the width in the sub-scanning direction is the distance between the nip portion of the transport rollers 126 and 127 and the nip portion of the paper discharge rollers 128 and 129. Even when a sheet shorter than 136.2 mm is conveyed, an affirmative determination is made in S11 and the jam processing (S7) is executed.

  On the other hand, if the second predetermined time has elapsed before the rear B sensor 320 is not turned off (S11: N) and the rear sensor 330 is not turned on (S13: N) (S12). : Y), when a jam (paper jam) occurs between the rear B sensor 320 and the rear sensor 330. Therefore, also when an affirmative determination is made in S12 during the loop process of S11 to S13, the process proceeds to S7 described above.

  Further, when the rear sensor 330 is turned on without the rear B sensor 320 being turned off (S11: N) and before the second predetermined time has passed (S12: N) (13: Y). ), When the leading edge of the transportable sheet is transported to the rear sensor 330. Therefore, in this case (S13: Y), the process proceeds to S14, and the paper (original) is conveyed to the reading start position by the second reading device 230 by driving the motor 550, which is a stepping motor, by a predetermined step. . In continuing S15, the reading process by the 2nd reading device 230 is performed, and a process is complete | finished.

[Processing in the above control system (duplex reading process)]
Next, FIGS. 8 and 9 are flowcharts showing a double-sided reading process executed by the CPU 420 of the ASIC 400 based on a program stored in the ROM 430. This process starts when double-sided scanning is instructed via the operation panel 600.

  As shown in FIGS. 8 and 9, since this process is the same as the single-sided reading process of FIG. A sheet that can be transported by the transport unit 100 such as A4 size or A5 size is transported, and before the first predetermined time elapses during the loop processing of S5 and S6 described above (S5: N), the rear B sensor 320 If it is ON (S6: Y), the process proceeds to S21. In S21, it is determined whether or not the rear B sensor 320 is OFF. If the rear B sensor 320 is not OFF (S21: N), the process proceeds to S22. In S22, after the rear B sensor 320 is turned on, the motor 550 is further driven by a predetermined step to determine whether or not the sheet has reached the reading start position by the first reading device 210, and the sheet is at the reading start position. If not reached (S22: N), the process proceeds to S21 again.

  Immediately after the rear B sensor 320 is turned ON, the loop processing of S21 and S22 is repeatedly executed, and if the sheet reaches the reading start position during that time (S22: Y), the back surface by the first reading device 210 in S23. A reading process is executed. In subsequent S24, it is determined whether or not the rear B sensor 320 is turned off. If not (S24: N), the second B sensor 320 is turned on in S25 after the rear B sensor 320 is turned on. It is determined whether or not a predetermined time has elapsed. If the second predetermined time has not elapsed (S25: N), it is determined in S26 whether or not the rear sensor 330 is ON. If the rear sensor 330 is not ON (S26: N). The process proceeds to S23 described above.

  As described above, when a sheet that cannot be transported by the transport unit 100 is transported obliquely, before the back side scanning process (S23) is started (S22: N) or the back side scanning process (S23). ) Is being turned on (S26: N), the rear B sensor is turned off (S21: Y or S24: Y). Therefore, in this case, the process proceeds to S7 described above. Further, when the second predetermined time elapses without the rear B sensor 320 being turned off (S24: N), and before the rear sensor 330 is turned on (S26: N) (S25). : Y), when a jam (paper jam) occurs between the rear B sensor 320 and the rear sensor 330. Therefore, also when an affirmative determination is made in S25 during the loop processing of S23 to S26, the process proceeds to S7 described above.

  Further, when the rear sensor 330 is turned on without the rear B sensor 320 being turned off (S24: N) and before the second predetermined time has elapsed (S25: N) (26: Y). ), When the leading edge of the transportable sheet is transported to the rear sensor 330. Therefore, in this case (S26: Y), the process proceeds to S27, and the back side reading process is continued. In S28, the motor 550 is driven by a predetermined step, and the reading of the sheet by the second reading device 230 is started. It is determined whether or not it has been transported to a position.

  If the sheet is not conveyed to the reading start position of the second reading device 230 (S28: N), the process proceeds to S27, the back side reading process is continued, and the sheet is moved to the reading start position of the second reading device 230. When transported, the reading process at S29 is executed, and the process ends. In S29, while the sheet faces the first reading device 210, the reading process on both the front and back sides using both the first reading device 210 and the second reading device 230 is executed, and the sheet is read in the second reading. While facing only the device 230, the surface reading process using only the second reading device 230 is executed.

[Effect of this embodiment and its modification]
As described above, in the present embodiment, it is detected using the front sensor 310, the rear B sensor 320, and the rear sensor 330 that the conveyance of the paper that cannot be conveyed by the conveyance unit 100 is erroneously started, The transfer can be stopped by shifting to the jam processing (S7). Moreover, the conveyance is stopped at a position where the sheet can be easily removed by opening the ADF cover 30A. As described above, in the present embodiment, even if a paper that cannot be transported is erroneously transported, it stops at a position where it can be easily removed, so that the operability of the apparatus is greatly improved.

  In addition, the front sensor 310, the rear B sensor 320, and the rear sensor 330 used for the detection all have the presence or absence of the paper placed on the paper feed tray 110, and the paper has reached the reading position of the first reading device 210. The sensor is conventionally used to detect that the paper has reached the reading position of the second reading device 230. Therefore, in the present embodiment, since the conveyance of the paper that cannot be conveyed can be suppressed without adding a special configuration, the configuration is hardly complicated as compared with the conventional apparatus, and an increase in manufacturing cost can be suppressed. .

  In addition, this invention is not limited to the said embodiment at all, It can implement with a various form in the range which does not deviate from the summary of this invention. For example, the paper conveying apparatus of the present invention can be used for an image forming apparatus or the like. In the above-described embodiment, the interval in the main scanning direction between the front sensor 310 and the rear B sensor 320 is defined in accordance with the specific standard paper size. However, many standard papers have a vertical / horizontal ratio. Since it is around 1: √2, the interval may be designed to be around √2 times (for example, ± 10%) of the longest interval of the roller nip portion.

DESCRIPTION OF SYMBOLS 1 ... MFP 10 ... Image reading device 20 ... Base | substrate 30 ... Document cover 30A ... ADF cover 31 ... Hinge 100 ... Conveyance part 110 ... Paper feed tray 121,122 ... Paper feed roller 123, 124, 125, 126, 127 ... Conveyance Roller 128, 129 ... paper discharge roller 130 ... paper discharge tray 210 ... first reading device 230 ... second reading device 310 ... front sensor 320 ... rear B sensor 330 ... rear sensor 351, 550 ... motor 400 ... ASIC M ... business card

Claims (8)

A transport unit having rollers disposed at a plurality of locations along the transport path, and transporting the paper placed on the paper feed tray along the transport path;
A first sensor for detecting a sheet conveyed by the conveyance unit;
A second sensor that is disposed downstream of the first sensor and detects a sheet conveyed by the conveying unit;
With
The transport unit is capable of transporting a paper whose length in the transport direction of the paper is longer than the longest interval along the transport path between the rollers,
The interval between the first sensor and the second sensor in the main scanning direction orthogonal to the conveying direction is longer than the width in the main scanning direction of a standard paper size that cannot be conveyed by the conveying unit. And the first sensor and the second sensor are respectively disposed,
Furthermore,
After the first sensor detects a sheet, a first predetermined time set longer than the time required for the sheet to be transported by the transport unit and reach the position detected by the second sensor has elapsed. If the second sensor does not detect the paper, a control unit for stopping the paper conveyance by the conveyance unit,
A sheet conveying apparatus comprising: The interval between the first sensor and the second sensor in the main scanning direction orthogonal to the conveying direction is shorter than the width in the main scanning direction of a standard paper size that can be conveyed by the conveying unit. The first sensor and the second sensor are respectively disposed;
The sheet conveying apparatus according to claim 1. A third sensor for detecting paper on the transport path downstream from the second sensor;
In addition,
The control unit also transports the paper by the transport unit even when the second sensor does not detect the paper until the third sensor detects the paper after the second sensor detects the paper. The sheet conveying device according to claim 2, wherein the sheet conveying device is stopped. A cover that covers a part of the transport path so as to be openable and closable;
In addition,
The first sensor detects paper placed on the paper feed tray,
The first predetermined time is a time required from when the paper is transported from the paper feed tray to when the part of the transport path is transported by the transport unit. Paper transport device. An interval along the transport direction of the plurality of rollers in the part of the transport path is configured to be shorter than a length in a transport direction of a sheet of a standard paper size that cannot be transported,
An interval along the conveyance direction of at least two of the rollers in the conveyance path downstream from the part is the longest interval.
The sheet conveying apparatus according to claim 4. The standard paper that cannot be transported by the transport unit is
The length of the paper of the impossible regular paper size in the main scanning direction is shorter than the interval between the first sensor and the second sensor in the main scanning direction orthogonal to the transport direction,
The length in the transport direction of the paper of the impossible standard paper size is shorter than the longest interval and longer than the interval between the plurality of rollers in the part of the transport path.
Be business card size paper,
The sheet conveying apparatus according to claim 5. A paper conveying device according to any one of claims 1 to 6,
An image reading unit that reads an image of at least one side of the sheet conveyed along the conveyance path;
An image reading apparatus comprising: A paper conveying device according to any one of claims 3 to 6,
A first image reading unit that reads an image of one surface of a sheet conveyed on the conveyance path on the downstream side of the second sensor in the conveyance path;
A second image reading unit that reads an image on the other surface of the sheet conveyed on the conveyance path on the downstream side of the first image reading unit and the third sensor in the conveyance path;
With
The second sensor detects that the paper has reached the reading position of the first image reading unit,
The image reading apparatus, wherein the third sensor detects that the sheet has reached a reading position of the second image reading unit.

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