JP5895696B2 - Paper transport device - Google Patents

Description

  The present invention relates to a sheet conveying apparatus, and more particularly, to a sheet conveying apparatus that conveys a sheet while correcting skew and misalignment of the fed sheet.

  In an automatic document feeder mounted on a document image reading device, it is important that the document is accurately conveyed in a direction orthogonal to the main scanning direction of the reading optical system so that the read image is not tilted. However, when feeding the set originals one by one, the original is inclined with respect to the transport direction because of an unstable situation (hereinafter referred to as skew or skew). ). Therefore, in the conventional automatic document feeder, a plurality of stacked documents are fed one by one and sent in one direction, and skew correction by a pair of registration rollers is performed on the downstream side. In other words, the skew is corrected by forming a loop by abutting the leading end of the sheet against the pair of registration rollers that have stopped rotating, and then the sheet is conveyed while maintaining the loop.

  Japanese Patent Application Laid-Open No. 2004-151561 describes a sheet conveying apparatus that performs skew correction by performing registration operations twice on a fed document. However, since the registration roller pair and the four roller pairs for feeding the original document are arranged for convenience, the conveyance path becomes long. In addition, since the pair of rollers arranged on the upstream side of the pair of registration rollers holds the document firmly, the skew correction is actually incomplete. Further, when the original is shifted in a direction orthogonal to the conveyance direction by skew correction, the original is not corrected, and a deviation of the read image in the main scanning direction occurs.

  Japanese Patent Application Laid-Open No. 2005-228561 describes a conveying device that includes a registration roll pair and a pre-registration roll pair arranged on the upstream side thereof, and is capable of moving the pre-registration roll pair in the axial direction and restraining the movement. In this apparatus, the pre-registration roll pair is brought into an unconstrained state, and the skew is corrected by bending the sheet between the registration roll pair and the pre-registration roll pair. However, in this apparatus, a pair of paper conveying rollers is further arranged upstream of the pair of pre-registration rollers, and when the pair of conveying rollers holds the paper firmly, the pair of pre-registration rollers is in a restrained state. Even if it exists, it cannot move in the axial direction, and as a result, the skew correction is incomplete.

JP 2004-352402 A JP 2003-128297 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a paper transport device that can effectively correct the skew of the fed paper and can also correct the skew of the paper after the skew correction.

A sheet conveying apparatus according to an aspect of the present invention is
A conveying roller pair to send transportable paper, a first pair of registration rollers for correcting skew abutted against the leading edge of the sheet conveyed by the conveying roller pair is conveyed by the first registration roller pair A second registration roller pair for abutting the leading edge of the sheet to correct skew,
The first registration roller pair is movable in the thrust direction perpendicular to the sheet conveying direction,
The transport roller pair holds and transports the paper,
After the sheet hits the first registration roller pair, the conveyance roller pair further conveys the sheet, so that the sheet moves between the first registration roller pair and the conveyance roller pair in a first loop. The first registration roller pair can move in the thrust direction due to the rigidity of the paper to eliminate the distortion of the paper due to the difference in height in the width direction of the paper forming the first loop, Perform skew correction on the paper,
After the sheet hits the second registration roller pair, the first registration roller pair further conveys the sheet, so that the sheet is transferred between the second registration roller pair and the first registration roller pair. Forming a second loop, and forming the second loop in a state where the first loop exists between the first registration roller pair and the transport roller pair at the time of forming the second loop; The first registration roller pair can be moved in the thrust direction due to the rigidity of the sheet to eliminate the distortion of the sheet due to the difference in height in the width direction of the sheet, and the skew correction to the sheet is performed.
It is characterized by.

  In the paper transport device, the skew correction is performed twice by the first registration roller pair and the second registration roller pair. The first registration roller pair that performs the first skew correction is movable in a thrust direction orthogonal to the sheet conveyance direction, and has moved in the thrust direction after performing the first skew correction. Therefore, in the second skew correction by the second registration roller pair on the downstream side, the skew correction is effectively performed without causing the paper to be twisted, and the result of the skew correction is There is no misalignment of the paper.

  According to the present invention, it is possible to effectively correct the skew of the fed paper and also to correct the deviation of the paper after the skew correction.

It is explanatory drawing in the vertical surface which shows the paper conveyance state in the basic form of a paper conveying apparatus. It is explanatory drawing in the horizontal surface which shows the paper conveyance state in the said basic form. It is explanatory drawing which shows the structure which enables the movement of the 1st registration roller pair to a thrust direction, a fixing means, and a return means. It is a flowchart figure which shows the control procedure in the said basic form. 1 is a schematic configuration diagram showing a first embodiment in which the present invention is applied to an automatic document feeder. FIG. It is a flowchart figure which shows the control procedure in the said 1st Example. It is a schematic block diagram which shows 2nd Example which applied this invention to the automatic document feeder. It is a flowchart figure which shows the control procedure in the said 2nd Example.

  Hereinafter, embodiments of a sheet conveying device according to the present invention will be described with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the same member and part in each figure, and the overlapping description is abbreviate | omitted.

(Basic form of paper transport device, see FIGS. 1 to 4)
First, the basic form of the paper conveying apparatus according to the present invention will be described. As shown in FIGS. 1 and 2, the sheet conveying apparatus includes a sheet feeding / dispersing roller pair 10 that conveys the sheet S in the direction of arrow A, a first registration roller pair 20, and a second registration roller pair 30. ing. Further, on the upstream side in the conveyance direction A of the paper feed / handing roller pair 10, a tray (not shown) for stacking and storing the paper S and a pickup roller for feeding the paper S to the paper feeding / handing roller pair 10 are provided. Yes. As shown in FIG. 2, the tray is provided with a side regulating plate 9 for regulating both sides of the paper S to a predetermined transport position. A paper detection sensor SE1 is installed on the downstream side of the paper feed / leaving path roller pair 10, and a paper detection sensor SE2 is installed on the upstream side of the second registration roller pair 30.

  The pair of paper feed / spreading rollers 10 includes a paper feed roller 11 fixed to the support shaft 12 and a feed roller 13 fixed to the support shaft 14. The sheet feeding roller 11 and the separating roller 13 are in contact with each other with a predetermined pressure, and are respectively rotated in the clockwise direction in FIG. A torque limiter is interposed between the winding roller 13 and the support shaft 14, and a plurality of sheets picked up by the pickup roller are rolled up by the roller pair 10 and fed in the direction of arrow A. Such a whispering operation is well known in the art.

  The first registration roller pair 20 is constituted by rollers 21 and 23 fixed to the support shafts 22 and 24, respectively. The roller 21 is pressed by the coil spring 25 as shown in FIG. Thus, the roller 23 is in contact with a predetermined pressure. When the upper roller 21 is rotationally driven in the clockwise direction in FIG. 1A, the lower roller 23 is driven to rotate. The driving side may be a roller 23. The second registration roller pair 30 includes rollers 31 and 33 fixed to the support shafts 32 and 34, respectively. The rollers 31 and 33 are in contact with each other with a predetermined pressure by a coil spring (not shown). When the upper roller 31 is rotationally driven in the clockwise direction, the lower roller 33 is driven to rotate. The driving side may be a roller 33.

  The first registration roller pair 20 is movable in a thrust direction B orthogonal to the transport direction A, can be fixed at the moved position, and can be returned to a predetermined initial position in the thrust direction B. This configuration will be described with reference to FIG. Both ends of the support shafts 22 and 24 are held by brackets 26, and the brackets 26 are held by two support shafts 27 provided in parallel so as to be movable in a thrust direction B via a thrust bearing 28. Yes.

  A damper member 41 is opposed to the end portion 26a of the bracket 26 by a solenoid 42 so as to be able to contact and separate. A return member 43 is opposed to the end portion 26b of the bracket 26 by a solenoid 44 so as to be able to contact and separate. The first registration roller pair 20 moves in the thrust direction B as described below when correcting the skew of the paper. At this time, when the solenoid 42 is turned on, the damper member 41 comes into pressure contact with the end portion 26a and the first registration roller 20 is turned on. The roller pair 20 is fixed at the moving position. The solenoid 42 is normally turned off, and the damper member 41 is separated from the end portion 26a. On the other hand, when the solenoid 44 is turned on while the damper member 41 is separated from the end portion 26a, the concave portion 43a of the return member 43 comes into pressure contact with the end portion 26b, and the first registration roller pair 20 is returned to a predetermined position. This return position is referred to as the initial position. The solenoid 44 is normally turned off, and the return member 43 is separated from the end portion 26b.

  The first registration roller pair 20 is movable in the thrust direction B at the first skew correction, and from the completion of the first skew correction to the start of the second skew correction, the thrust direction at the first skew correction. The position is fixed by the damper member 41 at the position moved to B, and after completion of the second skew correction, the restriction by the damper member 41 is released and the movement is possible in the thrust direction B. Then, the first registration roller pair 20 is returned to the initial position by the return member 43 in preparation for the next paper conveyance.

  Specifically, the first registration roller pair 20 and the second registration roller pair 30 are locked in rotation (step S1 in FIG. 4), and the solenoids 42 and 44 are in the OFF state (step S2), and the first registration roller pair 20 Is movable in the thrust direction B. Here, the paper feed roller 11 is driven to rotate (step S 3), and the paper S is fed by the paper feed / spreading roller pair 10. When the sensor SE1 detects the leading edge of the paper S and a predetermined time has elapsed (YES in step S4), that is, the leading edge of the paper S hits the first registration roller pair 20 whose rotation has been stopped, and the paper is upstream of that. When a necessary loop is formed at the tip of S (see FIG. 1B), the driving of the paper feed roller 11 is stopped once (step S5). At this time, when the paper S is skewed (see FIG. 2A), the first registration roller pair 20 is pressed by the leading end of the paper S and moves in the arrow B direction (see FIG. 2B). ), Skew and deviation of the sheet S are corrected (first skew correction). At the same time, the solenoid 42 is turned on to fix the first registration roller pair 20 at the moving position (step S6).

  Next, the paper feed roller 11 and the first registration roller pair 20 are driven to rotate (step S7). Thus, the sheet S is conveyed while maintaining a loop on the upstream side of the first registration roller pair 20 (see FIG. 1C). When the leading edge of the paper S is detected by the sensor SE2 (YES in step S8), the driving of the paper feed roller 11 is stopped (step S9), the solenoid 42 is turned off, and the first registration roller pair 20 is moved in the thrust direction B. (Step S10). Thereafter, the sheet S is transported while slipping with respect to the sheet feeding / leaving roller pair 10.

  Here, when the leading edge of the sheet S hits the second registration roller pair 30 whose rotation is stopped and a necessary loop is formed at the leading end of the sheet S on the upstream side thereof (YES in step S11), the first The rotation of the registration roller pair 20 is stopped (step S12). Since the first registration roller pair 20 is movable in the thrust direction B, the skew of the paper S is corrected (see FIG. 1D, second skew correction). That is, the skew of the sheet S is absorbed by the loop portion on the upstream side of the first registration roller pair 20.

  Next, the first registration roller pair 20 and the second registration roller pair 30 are rotationally driven (see FIG. 1E, step S13). As a result, the sheet S is conveyed while maintaining a loop on the upstream side of the second registration roller pair 30 and with the skew and the offset corrected. After the sensor SE2 detects the trailing edge of the sheet S (YES in step S14), the solenoid 44 is turned on (step S15), and the first registration roller pair 20 is returned to the initial position.

(Refer to the first embodiment of the automatic document feeder, FIGS. 5 and 6)
As shown in FIG. 5, the automatic document feeder 1A according to the first embodiment has a pair of sheet feeding / leaving rollers 10, a first pair of registration rollers 20, a first registration roller pair 20 with respect to a sheet feeding tray 7 having a pickup roller 8. Two registration roller pairs 30 are arranged, and further, conveyance roller pairs 51, 52, 53, and 54 are arranged to constitute a conveyance path 50 (refer to a one-dot chain line), and a paper discharge tray 55 is provided. The configuration in which the first registration roller pair 20 is movable and fixed in the thrust direction B is the same as that in the basic mode.

  A reading glass 61 is disposed between the pair of conveying rollers 51 and 52, and an image on the first surface of the document D is read by light irradiated from a first reading optical system (not shown) through the glass 61. Further, a second reading optical system 62 is disposed between the pair of conveying rollers 52 and 53, and an image on the second surface of the document D is read. In addition to the sensors SE1 and SE2, a document detection sensor SE3 is disposed upstream of the first surface reading position C.

  The path length F from the detection position of the sensor SE1 to the detection position of the sensor SE3 with respect to the document D is set to a length in which a document of A4 vertical size (long side is parallel to the transport direction A) is accommodated. Therefore, in the first embodiment, as shown in FIG. 5B, when the leading edge of the document D is in contact with the second registration roller pair 30, the trailing end portion of the document D is a paper feed / rolling roller. The state is held in the pair 10.

  A control procedure in the automatic document feeder 1A having the above configuration will be described with reference to FIG. First, the rotation of the first registration roller pair 20 and the second registration roller pair 30 is locked (step S21), and the solenoids 42 and 44 are in an off state (step S22), and the first registration roller pair 20 is in the thrust direction B. It is in a state where it can move freely. Here, the paper feed roller 11 is driven to rotate (step S 23), and the original is fed by the paper feed / leaving roller pair 10. After the sensor SE1 detects the leading edge of the document (YES in step S24), the leading edge of the document hits the first registration roller pair 20 whose rotation is stopped, and a necessary loop is formed at the leading edge of the document upstream. (Step S25). Thereafter, the driving of the paper feed roller 11 is stopped once (step S26). At this time, since the first registration roller pair 20 is movable in the thrust direction B, the skew and deviation of the original are corrected (first skew correction). At the same time, the solenoid 42 is turned on to fix the first registration roller pair 20 at the moving position (step S27).

  Next, the paper feed roller 11 and the first registration roller pair 20 are driven to rotate (step S28). Thus, the document is conveyed while maintaining a loop on the upstream side of the first registration roller pair 20. When the leading edge of the document is detected by the sensor SE2 (YES in step S29), the solenoid 42 is turned off to make the first registration roller pair 20 movable in the thrust direction B (step S30). Here, the leading edge of the document abuts against the second registration roller pair 30 whose rotation is stopped, and a necessary loop is formed at the leading edge of the document on the upstream side (step S31).

  Next, the rotation of the paper feed roller 11 and the first registration roller pair 20 is stopped (step S32). Since the first registration roller pair 20 is movable in the thrust direction B, the skew of the document is corrected (second skew correction). Thereafter, the first registration roller pair 20 and the second registration roller pair 30 are rotationally driven (step S33). As a result, the document is conveyed while maintaining a loop on the upstream side of the second registration roller pair 30 and with the skew and offset corrected. When the sensor SE2 detects the trailing edge of the document (YES in step S34), the solenoid 44 is turned on (step S35), and the first registration roller pair 20 is returned to the initial position.

(Refer to the second embodiment of the automatic document feeder, FIGS. 7 and 8)
As shown in FIG. 7, the automatic document feeder 1B according to the second embodiment has a paper feed / spreading roller pair 10, a transport roller pair 56, a first resist for a paper feed tray 7 having a pickup roller 8 as shown in FIG. A roller pair 20 and a second registration roller pair 30 are arranged, and a sensor SE4 for detecting a document is arranged on the upstream side of the first registration roller pair 20. Other configurations are the same as those of the first embodiment. In the second embodiment, the second registration roller pair 30 is disposed immediately before the first reading position C in order to minimize the skew of the document. For this purpose, the first registration roller pair 20 is also moved downstream, and a conveyance roller pair 56 (with a torque limiter) for conveying the original to the first registration roller pair 20 is provided.

  A control procedure in the automatic document feeder 1B having the above configuration will be described with reference to FIG. First, the rotation of the first registration roller pair 20 and the second registration roller pair 30 is locked (step S41), and the solenoids 42 and 44 are in an off state (step S42), and the first registration roller pair 20 is in the thrust direction B. It is in a state where it can move freely. Here, the paper feed roller 11 and the transport roller pair 56 are rotationally driven (step S43), and the original is fed by the paper feed / leaving roller pair 10 and further transported by the transport roller pair 56. After the sensor SE4 detects the leading edge of the document (YES in step S44), the leading edge of the document hits the first registration roller pair 20 whose rotation has been stopped, and a necessary loop is formed at the leading edge of the document on the upstream side. (Step S45). Thereafter, the driving of the paper feed roller 11 and the transport roller pair 56 is once stopped (step S46). At this time, since the first registration roller pair 20 is movable in the thrust direction B, the skew and deviation of the original are corrected (first skew correction). At the same time, the solenoid 42 is turned on to fix the first registration roller pair 20 at the moving position (step S47).

  Next, the paper feed roller 11, the transport roller pair 56, and the first registration roller pair 20 are rotationally driven (step S48). Thus, the document is conveyed while maintaining a loop on the upstream side of the first registration roller pair 20. When the leading edge of the document is detected by the sensor SE2 (YES in step S49), the solenoid 42 is turned off to make the first registration roller pair 20 movable in the thrust direction B (step S50). Here, the leading edge of the document abuts against the second registration roller pair 30 whose rotation is stopped, and a necessary loop is formed at the leading edge of the document on the upstream side (step S51).

  Next, the rotation of the paper feed roller 11, the transport roller pair 56, and the first registration roller pair 20 is stopped (step S52). Since the first registration roller pair 20 is movable in the thrust direction B, the skew of the document is corrected (second skew correction). Thereafter, the conveyance roller pair 56, the first registration roller pair 20, and the second registration roller pair 30 are rotationally driven (step S53). As a result, the document is conveyed while maintaining a loop on the upstream side of the second registration roller pair 30 and with the skew and offset corrected. When the sensor SE2 detects the trailing edge of the document (YES in step S54), the solenoid 44 is turned on (step S55), and the first registration roller pair 20 is returned to the initial position.

(Other examples)
In addition, the paper conveying apparatus based on this invention is not limited to the said Example, It can change variously within the range of the summary.

  For example, a configuration in which the first registration roller pair 20 is movable in the thrust direction B, a configuration for fixing the first registration roller pair 20 to the moving position, a configuration for returning to the initial position, and the like are arbitrary. Further, the configuration of the paper feed / spreading roller pair 10 is also arbitrary.

  As described above, the present invention is useful for a sheet conveying apparatus, and particularly, in that it can effectively correct skew of a fed sheet and can also correct deviation of the sheet after skew correction. Are better.

DESCRIPTION OF SYMBOLS 1A, 1B ... Automatic document conveying apparatus 10 ... Paper feed / stripping roller pair 20 ... First registration roller pair 30 ... Second registration roller pair 41 ... Damper member 43 ... Return member SE1, SE2, SE3 ... Sensor A ... Conveying direction B ... Thrust direction S ... Paper D ... Original

Claims (7)

A conveying roller pair to send transportable paper, a first pair of registration rollers for correcting skew abutted against the leading edge of the sheet conveyed by the conveying roller pair is conveyed by the first registration roller pair A second registration roller pair for abutting the leading edge of the sheet to correct skew,
The first registration roller pair is movable in the thrust direction perpendicular to the sheet conveying direction,
The transport roller pair holds and transports the paper,
After the sheet hits the first registration roller pair, the conveyance roller pair further conveys the sheet, so that the sheet moves between the first registration roller pair and the conveyance roller pair in a first loop. The first registration roller pair can move in the thrust direction due to the rigidity of the paper to eliminate the distortion of the paper due to the difference in height in the width direction of the paper forming the first loop, Perform skew correction on the paper,
After the sheet hits the second registration roller pair, the first registration roller pair further conveys the sheet, so that the sheet is transferred between the second registration roller pair and the first registration roller pair. Forming a second loop, and forming the second loop in a state where the first loop exists between the first registration roller pair and the transport roller pair at the time of forming the second loop; The first registration roller pair can be moved in the thrust direction due to the rigidity of the sheet to eliminate the distortion of the sheet due to the difference in height in the width direction of the sheet, and the skew correction to the sheet is performed.
A paper conveying device characterized by the above. The first registration roller pair is movable in the thrust direction during the first skew correction, and from the completion of the first skew correction to the start of the second skew correction in the thrust direction during the first skew correction. 2. The sheet conveying device according to claim 1, wherein the sheet conveying device is fixed at the moved position and is movable in the thrust direction at the time of the second skew correction. The first registration roller pair is movable in the thrust direction during the first skew correction until the first skew correction is completed after the leading edge of the conveyed paper reaches the first registration roller pair. Yes,
The position of the first registration roller pair is fixed from the completion of the first skew correction until the start of sheet conveyance toward the second skew correction,
The first registration roller pair is movable in the thrust direction until the leading edge of the sheet conveyed for the second skew correction reaches the second registration roller pair;
The sheet conveying apparatus according to claim 2.   The sheet conveying apparatus according to any one of claims 1 to 3, further comprising a damper member for fixing the first registration roller pair to a moving position in a thrust direction.   5. The sheet conveying apparatus according to claim 1, further comprising a returning unit that returns the first registration roller pair to an initial position in a thrust direction.   6. The sensor according to claim 1, further comprising: a sensor that detects a sheet to be conveyed, wherein the movement and fixing of the first registration roller pair is based on a detection signal of the sheet by the sensor. Paper transport device. The sheet conveying apparatus according to claim 1, wherein the conveying roller pair does not move in the thrust direction while holding and conveying a sheet.

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