JP2003063698A - Carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely realize skew correction even when paper is caught by register rollers or when it pierces a roller element in a carrying device provided with a skew correction mechanism. SOLUTION: A pair of pre-register rollers 20 are driven to rotate normally to carry paper P toward a pair of the register rollers 14. Next, at a prescribed time after a paper sensor 400 detects T0 a tip of the paper, drive for normal rotation of the register rollers 14 is stopped T1-T3, and drive for rotation of the pre-register rollers 20 is stopped T2-T5. At a proper timing T4 before or after the tip of the paper is abutted on the register rollers 14, the register rollers 14 are driven to rotate inversely T6-T7. Since the register rollers 14 are rotated inversely, a state of the paper caught or piercing the roller element is eliminated, and the tip of the paper is securely and uniformly abutted to the register rollers 14, thereby skew correction can be securely realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conveying device for conveying a sheet-shaped object to be conveyed such as paper. More specifically, for example, it is used in an image forming apparatus such as a copying machine or a printing device (printer), and the rotation of the downstream side transport unit is stopped to function as an abutting member, and the upstream side transport unit transports paper. The present invention relates to a conveying device having a mechanism for abutting a sheet on a downstream side conveying unit to correct the distortion of the sheet.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine or a printing apparatus, a photosensitive member on which a toner image is formed is formed by, for example, charging, exposing and developing a photosensitive member to form a toner image. A toner image is transferred onto the sheet by supplying sheet-shaped paper or originals (hereinafter also simply referred to as a sheet) to the drum, and an image is formed on the sheet by heating and pressing the sheet on which the toner image is transferred. is doing. In this process, the sheet is placed on the sheet conveyance path,
The sheet is conveyed by a pair of rolls that sandwich and convey the sheet.

By the way, when the sheet is conveyed by the pair of rolls in this way, for example, only one of the various rolls is disposed obliquely with respect to the sheet conveying path, or only one of the various rolls is arranged. Even if the sheet is formed with an uneven roll diameter, the sheet is conveyed by the roll in a direction deviated from the original conveying direction, that is, the direction along the sheet conveying path. The sheet is conveyed from the rolls in the state where the posture of the sheet is deviated from the conveying direction. Such a sheet conveyance state is called skew feed (skew, skew distortion). Then, for example, if the sheet is fed to the transfer position while being obliquely fed, the toner image is obliquely transferred to the sheet, and the image formed on the sheet is misaligned and formed.

In order to solve this problem, a pair of downstream side transport units, which also function as an abutting member on the upstream side of the transfer position of the sheet from the transfer position, and which sandwich (grip) the sheet and transport it. A registration roll (registration roll) is provided, and a pair of pre-registration rolls (a pair of pre-registration rolls) serving as an upstream-side conveyance unit that nips and conveys the sheet is provided on the upstream side of the sheet conveyance path with respect to the registration roll. ,
A large number of conveying devices having a mechanism for correcting one side of the sheet tip against an abutting member (registry roll) to correct skew distortion have been proposed (for example, Japanese Utility Model Laid-Open No. 58-158049 and Japanese Patent Laid-Open No. 1819134). .

[0005]

Here, for example, in the case of a strong sheet such as thick paper, the roller is used when the skewed sheet leading edge enters the roller nip (contact portion) of the pair of rotation-stopped registration rolls functioning as an abutting member. May get stuck in an element. In this case, one side of the leading edge of the sheet does not uniformly come into contact with the registration roll pair, so that skew distortion cannot be sufficiently corrected.

Further, in order to improve productivity in the case where a large number of sheets are continuously processed at one time, it is necessary to shorten the interval of waiting for conveyance of the previous sheet and the next sheet. Since one side must be brought into uniform contact with the registration roll pair, the next sheet must not be fed to the registration roll pair until the rotation of the registration roll pair is stopped after the previous sheet is conveyed. In other words, if the roller stop time variation, sheet feed amount variation, and skew amount variation are taken into consideration, and the safety factor is taken into account, a proper interval is not provided so that the next sheet tip will be in a registration roll pair. It rushes into the roller nip before stopping. When the sheet plunges into the roller nip, the sheet is sandwiched by the roller nip, and skew distortion cannot be corrected. In addition, if the sheet is conveyed to the downstream side in that state, the registration accuracy may be deteriorated.

The present invention has been made in view of the above circumstances, and reliably realizes skew correction even if a sheet is caught in the abutting portion of the downstream side transport portion or stuck in a roll element. It is an object of the present invention to provide a transport device that can be used.

[0008]

That is, in the carrying device according to the present invention, a sheet-shaped member to be conveyed is sandwiched between a pair of rotating bodies arranged on the upstream side of the conveying path for conveyance. The upstream transport unit and a pair of rotating bodies disposed on the transport path downstream of the upstream transport unit sandwich the transport target transported by the upstream transport unit and further downstream. And a downstream side transport unit that transports the target side to the front side, the upstream side transport unit is normally driven to transport the target body, and the target body is abutted against the downstream side transport section to correct skew distortion of the target body. The transport device for driving the downstream transport unit in reverse rotation at a timing near the tip of the transported object reaches the downstream transport unit, and after a lapse of a predetermined time, cancel the reverse drive of the downstream transport unit. A control unit for correcting the skew distortion is provided. The inventions described in the dependent claims define further advantageous specific examples of the conveying device according to the present invention.

Here, the "timing in the vicinity of the front end of the conveyed body reaching the downstream side conveying section" is not limited to the time when the front end of the conveyed body reaches the downstream side conveying section, but the front end is the downstream side conveying section. This means that it includes the time when a predetermined amount of paper has passed through the section and the time when the tip almost reaches the downstream side transport section (for example, immediately before). In short, appropriate timing in the vicinity where the tip of the transported object strikes the downstream side transport section. If

[0010]

In the carrying device of the present invention, the control section causes the downstream carrying section to reverse at an appropriate timing before and after the leading end of the article to be carried hits the downstream carrying section, and after a lapse of a predetermined time, the downstream carrying section. The skew distortion is corrected by canceling the reverse rotation of.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing an outline of the overall configuration of an embodiment of an image forming apparatus having a carrying section which is an example of a carrying apparatus according to the present invention. This image forming apparatus supplies a sheet to an image forming unit 100 that transfers a toner image onto a sheet (paper medium), which is an example of a sheet-shaped transported object, and a transfer position that transfers a toner image onto the sheet. It has a transport unit 200. Image forming unit 100 provided in the image forming apparatus
Is a rotatably arranged photosensitive drum 1, a charging corotron 2 for charging the photosensitive drum 1 to a uniform potential,
It is supplied to a transfer position between the photoconductor drum 1 and an exposing device 3 that exposes the photoconductor drum 1 after charging according to image information, a developing device 4 that supplies toner to the photoconductor drum 1 after exposure. And a transfer corotron 5 for transferring the toner onto the sheet P. The image forming unit 100 also includes a charge-removing corotron 6 for removing charge from the transferred sheet P and the photosensitive drum 1, a cleaning member 7 for removing dirt such as residual toner from the charge-removed photosensitive drum 1, and a sheet with respect to the transfer position. A heating roll pair 8 having a heating roll 8a and a pressure roll 8b that are pressed against each other at a fixing position on the downstream side of the conveyance direction of P and heat and press the paper P passing through the fixing position.
With this configuration, the image forming apparatus forms an electrostatic latent image on the photoconductor drum 1 with the charging corotron 2 and the exposing device 3,
The developing device 4 develops the electrostatic latent image to form a toner image,
The transfer corotron 5 transfers the toner image onto the paper P supplied to the transfer position, and the charge-removing corotron 6 removes the photosensitive drum 1.
The sheet P is separated from the sheet P, and the sheet P having the toner image transferred thereon is nipped and conveyed by the heating roll 8a and the pressure roll 8b to melt and fix the toner image on the sheet P.
An image is formed on the paper P. In addition, the cleaning member 7
Cleans the photosensitive drum 1 after transfer.

A transport unit 200 provided in the image forming apparatus
Are three paper trays 9 for accommodating a plurality of papers P, a discharge tray 10 for accommodating the papers P after image formation, and a paper P.
And various sheet guides 11 that regulate the conveyance direction of the sheet. The various paper guides 11 pull in the paper supply path L1 from each paper tray 9 to the transfer position, the paper discharge path L2 from the fixing position to the discharge tray 10, and the paper P on the discharge path L2, and the front and back sides thereof. The reversal path L3 of the sheet to be reversed and supplied to the supply path is set.

The transport unit 200 transfers paper P from each paper tray.
Of three pickup rolls 12 that carry out the paper P, a pair of friction rolls 13 that feed the paper P carried out from the paper tray 9 one by one to the supply path L1, and the paper P from the supply path L1 to the transfer position. A pair of registration rolls 14 to be supplied and a pair of pre-discharge rolls 15 to supply the sheet P after fixing to the carry-out path L2 are provided. The transport unit 200 also includes a pair of discharge rolls 16 that discharges the paper P from the discharge path L2 to the discharge tray 10, and a pair of pull-in rolls 17 that draws the paper P that passes through the discharge path L2 into the reversal path L3. A pair of reversing roll pairs 18 arranged in the middle of the reversing path L3 to reverse the conveying direction of the paper P, and a plurality of pairs of conveying rolls arranged on the supply path L1 or the reversing path L3 to convey the paper P. 19, a pair of transport rolls 20 arranged between the registration roll pair 14 and the transport roll pair 19, and supplying the paper P fed from the transport roll pair 19 to the transport roll pair 14.

The rolls other than the reversing roll pair 18 are pressed against each other in pairs (pairs) in a direction in which the rotation axis is in a direction perpendicular to the conveying direction of the paper P, and the press contact portion is the conveying path of the paper P. It is arranged so that it is located above,
In the state of being rotated in one direction, the paper P supplied to the pressure contact position is nipped and conveyed, and thereby the paper P is conveyed to the downstream side of the conveyance path. Inversion roll pair 1
The sheet P is pulled in the press contact portion and then rotated in the reverse direction.
Differs from other rolls only in that it operates so as to send it back in its loading direction.

In the carrying section 200 having such a structure,
The paper P stored in the paper tray 9 is supplied to the supply path L1 one by one by the pickup roll 12 and the friction roll pair 13, and the plurality of transport roll pairs 19,
It moves in the supply path L1 by 20 and the registration roll pair 1
4 to the transfer position, and the pre-discharge roll pair 15
Is discharged to the discharge tray 10 by the discharge roll pair 16 and is conveyed to the discharge tray 10. Further, the transport unit 200 uses the pair of pulling rolls 17 to reverse the paper P on the carry-out path L2 to the reverse path L.
3, the reversing roll pair 18 reverses the conveying direction of the paper P, and the plural conveying roll pairs 19 and 20 reverse the paper P.
Is re-supplied to the supply path L1, the paper P is turned over and supplied again to the transfer position and the fixing position.

When an image is formed on one side of the sheet P in the image forming apparatus thus constructed, the sheet P discharged from the sheet tray 9 is supplied to the transfer position via the supply path L1 and transferred. The toner image is transferred from the photosensitive drum 1 at the position, the toner image is fixed at the fixing position, and further discharged to the discharge tray 10 via the discharge path L2, so that an image is formed on one surface thereof. When images are formed on both sides of the sheet P, after the images are formed on one side of the sheet P, the images are formed on one side of the sheet P, and then the discharge path L2, the reverse path L3, and the supply path L1 are sequentially passed, and the front and back sides thereof are turned over and transferred again. To the position, the toner image is transferred from the photosensitive drum 1 at the transfer position, the toner image is fixed at the fixing position, and further discharged to the discharge tray 10 via the discharge path L2, whereby an image is formed on both surfaces thereof. To be done.

FIG. 2 is a diagram showing the details of the transport unit 200. The transport unit 200 corrects the posture of the paper P so that it is aligned in the transport direction, and then supplies it to the transfer position.
The registration roll pair 14 arranged on the conveyance path of the paper P is used as a downstream side conveyance unit, and the conveyance roll pair 20 (hereinafter referred to as a pre-registration roll pair) arranged on the upstream side of the conveyance path of the paper P is upstream. It is provided as a transport unit. Cash register pair 14
One of the pre-registration rolls 20 located inside the conveyance path is the drive registration roll 14a, and one located outside the conveyance path is the driven registration roll 14b. Those located outside the path are called driven pre-registration rolls 20b. The roll members of the registration roll pair 14 and the pre-registration roll pair 20 may be composed of a plurality of roll elements each having a narrow width and divided in the rotation axis direction. The paper transport path between these two roll pairs 14 and 20 is set in an arc shape.

The transport section 200 is disposed inside the transport path so as to face the first rotation shaft 21 disposed in parallel with the drive registration roll 14a and the upstream paper transport path of the registration roll pair 14, and the paper P And a registration sensor 25 for optically detecting the presence or absence of. Further, the transport unit 200 includes a second rotating shaft 26 disposed outside the transport path in parallel with the registration roll 14a, and an electromagnetic solenoid 27 disposed outside the transport path for linearly moving the movable iron piece 27a by an electromagnetic force. , One end of which is fixed to the rotating shaft 26 and which has an engaging portion 28a which engages with the movable iron piece 27a, and which is a part of the paper guide 11 outside the conveyance path between the registration roll pair 14 and the pre-registration roll pair 20. And a movable guide 28. Then, when the sheet P is carried in from the pre-registration roll pair 20, the rotation of the registration roll pair 14 is stopped and the movable guide 28 is set to the posture along the transport path.

FIG. 3 is a block diagram showing a schematic configuration of the control system 300 of the transport section 200. The control system 300 includes a drive motor 36 for driving the pre-registration rolls and a pair of registration rolls 14.
A transfer system controller 40 for controlling the operations of the drive motor 76 for various other roll members, the registration roll pair 14, the pre-registration roll pair 20, the electromagnetic solenoid 27 for moving the movable guide, and the toner on the photosensitive drum 1. An image system control unit 41 that forms an image and further transfers and fixes the toner image on the paper P, and a main control unit 42 that receives a paper detection signal of the registration sensor 25 and synchronously controls these two control units 40 and 41. Have. Then, when the image forming apparatus is activated, first, a paper carry-out signal is sent from the main control unit 42 to the transport system control unit 40, and in response thereto, the transport system control unit 40 causes the transport system control unit 40 to contact the register roll pair 14. The sheet P is conveyed until the leading edge of the sheet P comes into contact with the sheet P.

Next, at the timing after the detection signal of the paper P is input from the registration sensor 25 (corresponding to the paper sensor 400 described later) to the main control unit 42, the main control unit 42 causes the image system control unit 41 to operate. And transport system control unit 4
An image formation start signal is sent to 0, and in response thereto, the image system control unit 41 forms a toner image on the photosensitive drum 1, while the transport system control unit 40 moves the paper P from the registration roll pair 14 to the transfer position. To transfer the toner image onto the paper P,
Further, the toner image is fixed on the paper P and the discharge tray 1
Discharge to 0. In such a series of operations, the transport system control unit 40 moves the movable guide 28 or stops the rotation of the registration roll pair 14 to use the registration roll pair 14 as an abutting member after the image formation start signal is input. The rotation of the registration roll pair 14 and the pre-registration roll pair 20 is controlled so that the leading edge of the paper P is held in the contact portion (pressing contact portion, roller nip) to correct the posture of the paper (skew correction). Or

FIG. 4 is a diagram showing a first embodiment of the positional relationship between the registration roll pair 14 functioning as an abutting member and the pre-registration roll pair 20 serving as the upstream side transport unit, which are the main components of the transport unit 200. . The transport unit 200 has a mechanism for rotating the pre-registration roll pair 20. That is, first, the roll shaft 20c of the drive preregistration roll 20a.
A driven gear 34 is fitted and fixed to one end of the drive motor 36, and a drive motor 36 to which a drive gear 35 is fixed is provided on a main frame 31 (not shown) near the pre-registration roll pair 20. Each roll element of the pre-registration roll pair 20 may be configured to be movable in its axial direction. Further, the transport unit 200 has a mechanism for rotating the registration roll pair 14. That is, first, the driven gear 74 is fitted and fixed to one end of the roll shaft 14c of the drive registration roll 14a, and the drive motor 76 having the drive gear 75 fixed is disposed on the main frame 31 (not shown) near the registration roll pair 14. Has been done. The transport unit 200 further includes a paper sensor 4 that detects the leading edge of the paper P on the upstream side of the transport path near the registration roll pair 14.
00 (corresponding to the registration sensor 25 in FIG. 2).

Hereinafter, in this structure, the cash register roll pair 14
Of the sheet P is corrected by correcting the posture of the sheet P (correcting skew distortion) by stopping the rotation of the sheet P to function as an abutting member.
The operation of discharging will be described.

FIG. 5 is a diagram for explaining a first example of the drive control method of the registration roll pair 14 and the pre-registration roll pair 20 by the conveyance system control unit 40. FIG. 5A is a timing chart in this embodiment, FIG. 5B is a timing chart of a conventional example to which the present invention is not applied, and FIG.
(G) is a diagram showing the position of the paper P at a predetermined time. Each time point in the timing chart corresponds to the paper sensor 40.
0 when the leading edge of the paper is detected T0, when the current supply for forward rotation (normal rotation current supply) to the drive motor 76 for the registration roll pair 14 is stopped T1, and normal rotation to the drive motor 36 for the preregistration roll pair 20 is performed. It is time T2 when the current supply is stopped and time T3 when the forward rotation of the registration roll pair 14 is stopped. Further, to the drive motor 76 for the registration roll pair 14, a time point T4 at which the current supply for reverse rotation (reverse current supply) to the drive motor 76 for the registration roll pair 14 is started, a time point T5 at which the forward rotation of the pre-registration roll pair 20 is stopped, and T6 when the reverse rotation current supply of the register roll is stopped, and when the reverse rotation of the registration roll pair 14 is stopped T7
Is. Furthermore, the time T8 when the forward rotation current supply to the drive motors 36 and 76 for the roll pairs 14 and 20 is started, the time T9 when the roll pairs 14 and 20 reach the steady rotation speed, and the paper sensor 400 moves the trailing edge of the paper. Detected time T10, paper P
Is the time point T11 when the leading edge of the sheet hits the registration roll pair 14.

After the time T8 when the forward rotation current supply to the drive motors 36 and 76 is started, the paper P is discharged toward the photoconductor drum 1 by rotating the roll pairs 14 and 20 in the normal rotation while synchronizing the rotations. . From the time T10 when the paper sensor 400 detects the rear end of the paper to the time T0 when the front end of the paper is detected is the conveyance waiting time T22 of the previous sheet and the next sheet. Further, from the time T11 when the leading edge of the paper P hits the registration roll pair 14 to the time T5 when the forward rotation of the pre-registration roll pair 20 is stopped, the paper P is bent between the registration roll pair 14 and the pre-registration roll pair 20 to form a loop. This is the original period for forming and correcting skew distortion. On the other hand, in the present embodiment, since the registration roll pair 14 is reversed, this reverse rotation period T24 is also substantially incorporated in the skew distortion correction period (loop formation period). In addition, from the time T10 when the paper sensor 400 detects the rear end of the paper, the paper P
The interval until the time point T11 when the leading edge of the sheet hits the registration roll pair 14 is substantially zero (“0”) if the sheet sensor 400 detects the leading edge of the sheet P in the immediate vicinity of the registration roll pair 14. be able to.

First, the transport system controller 40 drives the drive motor 36 for the pre-registration roll pair 20 to drive the pre-registration roll pair 20 in the normal direction to transport the paper P to the registration roll pair 14 side. Next, after a lapse of a predetermined time after the paper sensor 400 provided near the registration roll pair 14 detects the position of the leading edge of the paper (T0), the drive motor 76 for the registration roll pair 14 is detected.
To the register roll pair 1 by stopping the current supply to (T1 to T3)
The normal rotation drive of No. 4 is stopped, and the registration roll pair 14 is made to function as an abutting member. Next, the conveyance system control unit 40 stops the forward rotation driving of the pre-registration roll pair 20 after a predetermined time has elapsed since the paper sensor 400 detected the position of the paper leading edge (T2 to T5). As a result, 20
Conveys the paper P toward the registration roll pair 14 which is shifting to the rotation stopped state.

Further, the conveyance system control unit 40 causes the sheet sensor 400 to detect (T0) the leading edge of the sheet, and after a predetermined time has passed, that is, before and after the leading edge of the sheet hits the registration roll pair 14 which is an example of the downstream side conveying section. Appropriate time (T4)
Then, a reverse current is supplied to the drive motor 76 for the registration roll pair 14 to drive the registration roll pair 14 in the reverse direction. Then, after a further predetermined time (T6), the reverse current to the drive motor 76 for the registration roll pair 14 is stopped to cancel the reverse rotation drive of the registration roll pair 14 (stop in this example) (T6 to T).
7). That is, the transport system controller 40 controls the register roll pair 14
Is reversed by a predetermined amount, and then skew correction is performed. As a result, the paper P carried in by the pre-registration roll pair 20
Is conveyed in the direction of the registration roll pair 14 (FIG. 5 (C)),
One side (leading edge) of the leading edge of the paper P is uniformly abutted against the registration roll pair 14 which is in a substantially stopped state (FIG. 5).
(D)) Further, when the pre-registration roll pair 20 conveys the sheet P, a bending loop is formed between the pre-registration roll pair 20 and the registration roll pair 14 to correct skew distortion (FIG. 5 (E)). From the timing (T0) when the paper sensor 400 detects the leading edge of the paper P, the pre-registration roll pair 2 is started.
The loop amount can be controlled by controlling the time (T5) until the rotation drive of 0 is stopped.

Next, the transport system controller 40 stops the forward rotation of the pre-registration roll pair 20 (T5) (or the registration roll pair 1).
After a lapse of a fixed time after the reverse rotation of 4 is stopped (T7), the registration roll pair 14 and the pre-registration roll pair 20 are synchronously driven to start the conveyance of the paper P (T8), and the paper P is directed to the photoconductor drum 1. To discharge. At this time, after the skew correction, the registration roll pair 14 and the pre-registration roll pair 20 are activated in synchronization with the image writing timing or the like to synchronize the leading edge of the sheet with the image. Hereinafter, the same processing as above is repeated for the next sheet.

When the leading edge of the sheet rushes into the contact portion of the registration roll pair 14 before the forward rotation of the registration roll pair 14 is stopped,
As shown in FIG. 5F, the vicinity of the leading edge of the paper P is sandwiched between the registration roll pair 14. However, as mentioned above,
In the present embodiment, since the registration roll pair 14 is once reversed for a predetermined time (predetermined amount), the paper P is returned in the direction opposite to the conveyance direction and the sandwiched state is released.
One side of the leading edge of the sheet surely and uniformly abuts the registration roll pair 14 (FIG. 5 (E)). Further, for example, when a strong sheet such as thick paper enters the roller nip of the registration roll pair 14 in a skewed state, as shown in FIG.
The vicinity of the tip of the roller may stick into the roller element. However, also in this case, since the register roll pair 14 is once reversed for a predetermined time, the stuck state (the state of being stuck) is released, and one side of the leading edge of the sheet is surely and uniformly placed on the contact portion of the register roll pair 14. Abut (Fig. 5
(E)). In this way, at the above timing, cash register rolls 1
By controlling the forward rotation, the stop, and the reverse rotation of the sheet 4,
Even if the paper is sandwiched between the registration roll pair 14 or stuck to the roll element, the skew correction can be surely realized (the skew correction capability is improved), and the alignment accuracy of the read image is improved.

Further, since the sandwiched state can be released by reversing, the rear end of the front sheet is paired with the registration roll pair 14.
As long as the sheet P passes through (for example, after the time T10), the sheet P can be abutted against the registration roll pair 14 without waiting for the registration roll pair 14 to completely stop. For example, as shown in FIG. 5B, in the conventional case, even if there are variations in sensor detection or variations in the conveyance speed, the leading edge of the paper P is reliably removed after the time T3 when the forward rotation of the registration roll pair 14 is stopped. In order to detect (T0), it was necessary to take a sufficiently long transfer waiting time T32 in anticipation of the safety factor.
In the above-described embodiment, as shown in FIG. 5A, the leading edge of the paper P may be detected before the time T3 when the forward rotation of the registration roll pair 14 is stopped, and the conveyance waiting time T22 can be set short. Therefore, although the reversing time T24 for reversing the registration roll pair 14 increases, T22 + T24 <T
32 (conventional transfer waiting time). That is, the entire processing time (one cycle) T20 for one sheet P can be shortened as compared with the conventional method (T30) by reducing the conveyance waiting interval between the previous sheet and the next sheet to a level that is not available in the conventional method. , High productivity can be achieved.

As described above, according to the above-described embodiment, when the sheet P, which is an example of the conveyed body, is continuously conveyed, the leading end of the sheet reaches the registration roll pair 14 which is an example of the downstream side conveying section. At a timing (T4 in the above example) in the vicinity of (T11), a fixed amount of each registration sheet P for each paper sheet P
4 is reversed, and after a predetermined time has elapsed (in the above example, T
In 7), the reverse rotation of the registration roll pair 14 is released to correct the skew distortion. Therefore, even when the paper P is pinched or pinched, the skew can be surely corrected and the total processing time is reduced. It can be shortened.

Also, for example, Japanese Patent Laid-Open No. 2000-12840.
The sheet feeding device described in No. 0 (referred to as Conventional Example 1) performs skew correction on all sheets with the registration roll pair 14
After the leading edge of the sheet passes through the contact portion of the conveying roller corresponding to the above, the feeding roller corresponding to the pre-registration roll pair 20 must be stopped and the conveying roller must be reversed to form a loop. Therefore, the amount of reversal is relatively large, resulting in a large time loss. On the other hand, the transport unit 200 of the above-described embodiment normally performs the skew correction by stopping the rotation of the registration roll pair 14 and transporting the sheet P to the registration roll pair 14 side by the pre-registration roll pair 20 to form a loop. Therefore, the register roll pair 14 is reversed by a predetermined amount for the purpose of canceling the pinching or biting. Since the predetermined amount is smaller than the reverse amount for loop formation in Conventional Example 1, the time loss is small.

FIG. 6 is a diagram for explaining another example of the drive timing of the registration roll pair 14 and the pre-registration roll pair 20 by the conveyance system control unit 40. In the first example, the reverse rotation of the registration roll pair 14 is started immediately before the time point T5 when the pre-registration roll pair 20 is stopped, that is, in the middle of the transition of the pre-registration roll pair 20 to the stopped state (during the slowdown). As shown in FIG. 6A, after the normal rotation of the pre-registration roll pair 20 is completely stopped, the registration roll pair 14 is rotated.
You may start the reversal of. In addition, 20
During normal rotation, that is, while maintaining the state in which the paper P, which is an example of the transported object, is transported to the registration roll pair 14 side,
The reverse rotation of the register roll pair 14 may be started. in this case,
Skew correction is performed by bending the sheet P between the pre-registration roll pair 20 in the forward rotation and the registration roll pair 14 in the reverse rotation to form a loop. And in this case, cashier roll pair 14
The inversion period T24 of is within the loop creation period, that is, the skew correction period. Further, in this case, for example, as shown in FIG.
The forward rotation current to the register roll pair 14 is suddenly switched to the reverse rotation current at the time T0 when the front end of is detected, so that the forward rotation is changed to the reverse rotation in a short time directly, that is, without substantially stopping. You can also Further, for example, as shown in FIG. 6C, the entire processing time can be further shortened by shortening the stop period T5 to T8 of the pre-resist roll pair 20.

FIG. 7 is a diagram showing a second embodiment of the positional relationship between the registration roll pair 14, the pre-registration roll pair 20, and the peripheral members. The present embodiment is different from the first embodiment in that a nipping state detection unit that detects whether or not the vicinity of the leading edge of a sheet P that is an example of a conveyed object is pinched by a registration roll pair 14 that is an example of a downstream side conveyance unit. That is, the cash register roll pair 14
A plurality of paper sensors 402 for detecting the leading edge of the paper P are provided on the downstream side of the nearby conveyance path. Each paper sensor 402
Function as the sandwiched state detection unit 412. The paper sensor 402 may detect the presence or absence of the paper P without contacting the paper P like a reflection-type or transmissive optical sensor, or may detect the presence or absence of the paper P by contacting the paper P. It may be one that does. For example, the sandwiching state detection unit 412 can be configured by a light source such as an LED as an optical sensor and a photodiode or phototransistor that is a light receiving unit, or a photocoupler.

Two paper sensors 402 are arranged in pairs for each size of the paper P so as to detect the vicinity of both widthwise edges of the paper P. In the figure, the relationship is shown by a dotted line. The output signal of each sheet sensor 402 is sent to the transport system control unit 40. Since the paper sensor 402 is disposed in the vicinity of the registration roll pair 14 and further on the downstream side of the transport path, when the tip of the paper P is brought into contact with the registration roll pair 14 and skew correction is performed, the paper sensor 402 detects the paper P.
Based on whether or not the paper P is detected, the paper P is paired with the registration roll 14
It is possible to detect whether or not it is sandwiched between. For example, the time T at which the paper P strikes the registration roll pair 14
During the original skew correction period after 11 the paper sensor 40
When 2 detects the sheet P (this state is referred to as a pinching signal), it indicates that the sheet P is pinched by the registration roll pair 14. Therefore, the transport system control unit 40 first stops the rotation of the registration roll pair 14 for skew correction to cause the registration roll pair 14 to function as an abutting member, and causes the pre-registration roll pair 20 to transport the paper P to the registration roll pair 14 side. . After that, under the condition that one of the paper sensors 402 outputs the nipping signal, that is, the paper P is nipped by the registration roll pair 14,
The register roll pair 14 is reversed by a fixed amount. On the other hand, when no pinching signal is output from any of the sheet sensors 402, skew correction is performed as usual without reversing the registration roll pair 14.

That is, in the first embodiment, the register roll pair 14 is always reversed by a predetermined amount for each sheet, whereas in the second embodiment, the sensor P is used to make the sheet P the register roll pair. The register roll pair 14 is reversed by a predetermined amount only when it is sandwiched between the rollers 14. However, also in this second embodiment,
When the paper P is sandwiched by the registration roll pair 14, it is possible to surely detect that, and one side of the leading edge of the sheet can be reliably brought into contact with the registration roll pair 14. Therefore, as in the first embodiment, the paper P Even if the sheet is caught between the registration roll pair 14, the skew correction can be surely realized. In addition, since the rotation is reversed only when it is sandwiched, for example, the configuration shown in FIG.
Even when the reverse rotation period is set at the timing shown in (A), by shortening the stop period T5 to T8 of the pre-registration roll pair 20 when there is no pinching and there is no need for reverse rotation,
The overall processing time can also be shortened. In addition, since it is not reversed when it is not pinched (when reverse rotation is unnecessary), power consumption does not increase more than necessary.

At the control timing of the second embodiment, the registration roll pair 1 is used only once at a predetermined constant amount.
Since 4 is reversed, there is a possibility that the pinched state cannot be released when the passing amount is large depending on the setting of the predetermined amount. On the other hand, in the arrangement of the second embodiment described above, until any one of the sheet sensors 402 detects a sandwiching signal until the sandwiching state is released and one side of the sheet P contacts the registration roll pair 14 substantially uniformly. Until is no longer output
The reverse rotation of the registration roll pair 14 can be repeated any number of times with a predetermined fixed amount (including continuing the reverse rotation state; the same applies hereinafter). Accordingly, even with the arrangement configuration of the second embodiment, the pinched state can be reliably released regardless of the passing amount.

Further, in the second embodiment, the paper sensors 402 are arranged so that two pairs are formed for each size of the paper P so as to detect the vicinity of both widthwise edges of the paper P. However, for example, a long CCD line sensor may be arranged so that the longitudinal direction thereof extends along the width direction to form the sandwiching state detection unit 412. In this case, one line sensor having a length sufficient to detect the vicinity of the side edge of the paper P having the maximum width may be used, or the vicinity of the side edge of the paper P having the minimum width to the maximum width in the vicinity of both edges. It is also possible to use two line sensors which are slightly shorter than the line sensor for detecting.

FIG. 8 is a diagram showing a third embodiment of the positional relationship among the registration roll pair 14, the pre-registration roll pair 20, and the peripheral members. The first embodiment is that a passage amount detection unit that detects a passage amount that is an amount of a sheet P that is an example of a transported object and that is near an end of a sheet P that is passing through a registration roll pair 14 that is an example of a downstream-side transportation unit is provided. Different from That is, cash register roll 1
A plurality of long paper sensors 404 for detecting the leading edge of the paper P are provided downstream of the transportation path in the vicinity of 4 such that the longitudinal direction thereof is along the transportation direction. Each paper sensor 404
Has a plurality of detection elements in the longitudinal direction (that is, in the transport direction), and based on which detection element detects the sheet P, the leading end position of the sheet P, that is, the registration roll pair of the sheet P. The amount of passage from 14 can be shown. In this way, each sheet sensor 404 is connected to the passage amount detection unit 4
Function as 14. The paper sensor 404 may detect the presence or absence of the paper P without contacting the paper P as in the second embodiment, or may detect the presence or absence of the paper P by contacting the paper P. It may be.

Each sheet sensor 404 is a pair of two sheets for each size of the sheet P so as to detect the passing amount of the sheet P from the registration roll pair 14 in the vicinity of both widthwise edges of the sheet P. It is arranged. In the figure, the relationship is shown by a dotted line. A passage amount signal indicating the leading end position of the sheet P detected by each sheet sensor 404 is sent to the conveyance system control unit 40. The paper sensor 40 is stored in a memory (not shown) of the transport system controller 40.
4 stores a table in which the value of the passage amount signal output from No. 4 and the reverse rotation amount of the registration roll pair 14 are associated with each other. Since the paper sensor 404 provided with a plurality of detection elements in the longitudinal direction is arranged near the registration roll pair 14 and further on the downstream side of the conveyance path, it is attempted to bring the leading edge of the paper P into contact with the registration roll pair 14 to perform skew correction. Not only whether or not the paper P is pinched, but also the registration roll pair 1 of the paper P
The passing amount from 4 can be detected. Therefore, the transport system control unit 40 first stops the rotation of the registration roll pair 14 for skew correction to cause the registration roll pair 14 to function as an abutting member, and causes the pre-registration roll pair 20 to transport the paper P to the registration roll pair 14 side. . Then, the reverse rotation amount of the registration roll pair 14 corresponding to the passage amount signal from the paper sensor 404 is determined based on the table, and the registration roll pair 14 is reversed by the determined reverse rotation amount. on the other hand,
When no passage amount signal is output from any of the sheet sensors 404, skew correction is performed as usual without reversing the registration roll pair 14.

That is, the third embodiment is common to the second embodiment in that the registration roll pair 14 is reversed only when the paper P is sandwiched by the registration roll pair 14.
On the other hand, the third embodiment differs from the second embodiment in that the reverse rotation is performed by a predetermined amount in that the reverse rotation is performed by an amount corresponding to the passing amount.
Accordingly, in the second embodiment, depending on the setting of the predetermined amount, there is a possibility that the sandwiched state cannot be released when the passing amount is large, whereas in the third embodiment, the paper sensor 404 having a sufficient length is used. By doing so, the state can be reliably released regardless of the passing amount.

At the control timing of the third embodiment, although the registration roll pair 14 is reversed by the amount corresponding to the passing amount, the number of times of reversing is once, so the correspondence relationship between the passing amount and the reverse amount is shown. When the paper P is not returned in the reverse direction by the expected amount due to improperness or slippage, the pinched state may not be released. on the other hand,
In the arrangement of the third embodiment described above, for example, any sheet sensor 40 is detected until it is detected that the sandwiched state is released and one side of the sheet P abuts the registration roll pair 14 substantially uniformly.
It is possible to repeat the reverse rotation of the registration roll pair 14 many times by a previously associated amount until the passage amount signal is not output from 4 as well. As a result, even in the arrangement configuration of the third embodiment, even if the paper P is not returned in the reverse direction by the expected amount due to slippage or the like, the pinched state can be reliably released.

Further, in the third embodiment, two pieces of each paper P are paired for each size of the paper P so that the amount of the paper P passing from the registration roll pair 14 can be detected in the vicinity of both widthwise edges of the paper P. Although the long paper sensor 404 is arranged so as to become, a plurality of the same sensors as those of the first embodiment are arranged in the transport direction, and one sensor is substantially formed by these plural sensors. You may make it function as the passage amount detection part 414 by comprising a long sensor.

Further, for example, a rectangular CCD area sensor may be provided. In this case, one area sensor having a width sufficient to detect the vicinity of the side edge of the paper P having the maximum width may be used, or the vicinity of the side edge of the paper P having the minimum width to the maximum width may be provided in the vicinity of both edges. 2 that is slightly narrower than the amount of detection
The passage amount detection unit 414 may be configured by using one area sensor.

FIG. 9 is a diagram showing a fourth embodiment of the positional relationship between the registration roll pair 14, the pre-registration roll pair 20, and the peripheral members. The point is that a contact state detection unit is provided to detect whether or not the vicinity of the leading edge of the sheet P, which is an example of the transported object, is substantially uniformly contacting the registration roll pair 14 that is an example of the downstream-side transportation section. Different from the first embodiment. That is, a paper sensor 406 for detecting the leading edge of the paper P is provided on the upstream side of the conveyance path near the registration roll pair 14. Paper sensor 406
Function as the contact state detection unit 416. The paper sensor 406 may detect the presence or absence of the paper P without contacting the paper P as in the second embodiment, or the paper P.
The presence or absence of the paper P may be detected by contacting with the paper P. Removing the paper sensor 400 of the first embodiment,
The leading edge of the paper P is detected based on the output signal of the paper sensor 406.

The paper sensor 406 is arranged so as to detect the leading end of the paper P in the vicinity of the upstream side pole of the registration roll pair 14 in the substantially central portion of the paper P in the width direction. The output signal of the paper sensor 406 is sent to the conveyance system control unit 40. Paper sensor 4
Since 06 is disposed in the vicinity of the registration roll pair 14 and on the upstream side of the conveyance path, the paper sensor 406 detects the paper P when the tip of the paper P is brought into contact with the registration roll pair 14 for skew correction. It is possible to detect whether or not the paper P is in contact with the registration roll pair 14 substantially uniformly based on whether or not it is done. For example, when the paper sensor 406 detects the paper P during the original skew correction period after the time T11 when the paper P strikes the registration roll pair 14 (this state is referred to as a uniform contact signal), the paper P is in the registration roll pair 14. It is shown that the contact is made substantially uniformly. On the other hand, when the paper sensor 406 does not detect the paper P,
For example, the vicinity of the leading edge of the paper P is pierced by the roller element, so that the paper P does not uniformly contact the registration roll pair 14. Therefore, the transport system control unit 40 first stops the rotation of the registration roll pair 14 for skew correction to cause the registration roll pair 14 to function as an abutting member, and causes the pre-registration roll pair 20 to transport the paper P to the registration roll pair 14 side. . Thereafter, the register roll pair 14 is reversed by a certain amount on condition that the sheet sensor 406 does not output the uniform contact signal, that is, the sheet P does not uniformly contact the register roll pair 14. on the other hand,
When the uniform contact signal is not output from the paper sensor 406, skew correction is performed as usual without reversing the registration roll pair 14.

That is, in the first embodiment, the register roll pair 14 is always reversed once for each sheet, whereas in the fourth embodiment, the sheet P uniformly contacts the register roll pair 14. The register roll pair 14 is once reversed by a predetermined amount only when there is no state. However, also in the fourth embodiment, when the sheet P pierces the registration roll pair 14, the state can be reliably released and one side of the leading edge of the sheet can be reliably brought into contact with the registration roll pair 14. Similar to the embodiment, even if the paper P is stuck into the registration roll pair 14, the skew correction can be surely realized.

In the fourth embodiment, the paper sensor 406 is arranged so as to detect the leading edge of the paper P near the center of the paper P in the width direction and in the immediate vicinity of the registration roll pair 14. In order to detect the vicinity of both edges of the paper P in the width direction, two point sensors are arranged for each size of the paper P, or a short CCD line sensor is arranged in the width direction. Then, the contact state detection unit 416 may be configured. In the former case, when at least two of the pair detect the leading edge of the sheet P, the sheet P contacts the register roll pair 14 uniformly, and when either or both do not detect the leading edge of the sheet P, the sheet P It can be determined that P does not uniformly contact the registration roll pair 14. In the latter case, when all the pixels of the CCD line sensor detect the leading edge of the sheet P, the sheet P uniformly abuts on the registration roll pair 14, and when any pixel does not detect the leading edge of the sheet P, the sheet P is detected. It can be determined that P does not uniformly contact the registration roll pair 14.

In the control timing of the fourth embodiment, the register roll pair 14 is used only once at a predetermined constant amount.
However, a long sensor for detecting the unreached amount of the paper P from the registration roll pair 14 is arranged so that its longitudinal direction is along the transport direction (only the central portion in the width direction). However, the registration roll pair 14 may be reversed by an amount corresponding to the unreached amount.

Further, if the register roll pair 14 is reversed only once in accordance with a predetermined fixed amount or an unachieved amount, depending on the setting of the predetermined amount, there is a possibility that the state cannot be released when the bite is intense. is there. On the other hand, in the arrangement configuration of the fourth embodiment, a predetermined constant amount or an unattained amount is reached until it is detected that the bite state is released and one side of the sheet P substantially uniformly abuts the registration roll pair 14. The reverse rotation of the register roll pair 14 can be repeated many times according to the amount. Thereby, even in the arrangement configuration of the fourth embodiment, the state can be reliably released regardless of the bite state. In this case, in order to avoid bending (buckling) of the leading edge of the sheet, an example of the upstream-side transport unit is used until it is detected that the biting state has been completely released and the sheet P has contacted the registration roll pair 14 substantially uniformly. It is preferable that the rotation of the pre-registration roll pair 20 is stopped.

Although the present invention has been described using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. Various changes or improvements can be added to the above-described embodiment, and a mode in which such changes or improvements are added is also included in the technical scope of the present invention. Also,
The above embodiments do not limit the claimed invention, and all combinations of the features described in the embodiments are not necessarily essential to the solution of the invention.

For example, by combining any of the second and third embodiments with the fourth embodiment, the register roll pair 14 is reversed only in each of the sandwiching state and the biting state only in each state. Good. Further, for example, in the above-described second and third embodiments, when repeating the reverse rotation of the registration roll pair 14 until the sandwiched state is released, the sandwiching state detection unit that uses the sheet sensor 402 to detect whether or not the sandwiched state is present. Although the passage amount detector 414 that detects the passage amount using the sheet 412 and the sheet sensor 404 detects whether the sandwiched state is released, the contact state detector 416 of the fourth embodiment is used. Good. In this case, a sensor for detecting the vicinity of both widthwise edges of the paper P is provided, and the pair of sensors at both ends detect the leading edge of the paper P, that is, the paper P uniformly abuts on the registration roll pair 14. It is preferable that the reversal of the registration roll pair 14 is repeated until the above is indicated.

Further, in the above embodiment, for example, after reversing the registration roll pair 14, the rotations of the registration roll pair 14 and the preregistration roll pair 20 are once stopped, and after a predetermined time has elapsed, the registration roll pair 14 and the preregistration roll pair 2 are stopped.
0 was synchronously driven to start the conveyance of the paper P, and the paper P was discharged toward the photosensitive drum 1. However, without waiting for the reverse rotation of the registration roll pair 14 to be completely stopped, the registration roll pair 14 Alternatively, the synchronous drive (normal rotation) of the pre-registration roll pair 20 may be started. In this case, skew correction is performed by bending the sheet P between the pre-registration roll pair 20 in the rotation stopped state and the registration roll pair 14 in the substantially rotation stopped state to form a loop.

Further, in the above-described embodiment, the object to be conveyed is conveyed to the side of the downstream side conveying portion by the upstream side conveying portion, and the conveyed body is bent at the downstream side of the conveying path of the upstream side conveying portion to form a loop. Although the skew distortion of the transfer body is corrected, the present invention is not limited to this, and the skew distortion is corrected by pressing (butting) the transfer target body to the downstream side transfer section without forming a loop. May be.
It is to be noted that the configuration in which the loop is formed to correct the skew distortion as in the above embodiment can realize the skew correction with higher accuracy.

Further, in the above description, the paper (paper medium) has been described as an example of the transported body, but the transported body is not limited to this, and as long as it is a sheet-like one, what is its material such as a plastic film. It may be.

In the above description, the transfer device for the transfer portion used in the image forming apparatus has been described as an example. However, the transfer device of the present invention is not limited to this, and for example, an automatic document feeder for image reading ( It may be used for Auto Document Feeder (ADF). Further, the image forming apparatus is not limited to an image forming apparatus such as a copying machine or a printing apparatus, and may be used for other things.

[0057]

As described above, according to the present invention, when the skew is corrected, the downstream side transport portion is once driven in the reverse direction, so that the transported object is sandwiched between the contact portions of the downstream side transport portion. Even if the roll element or the roll element is stuck, skew correction can be surely realized.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of an overall configuration of an embodiment of an image forming apparatus including a conveying device according to the present invention.

FIG. 2 is a diagram illustrating details of a transport unit.

FIG. 3 is a block diagram showing a schematic configuration of a control system of a sheet conveying unit.

FIG. 4 is a pair of cash register rolls, which are main components of the transport unit,
It is a figure which shows 1st Embodiment of a positional relationship of a pre-registration roll pair and a peripheral member.

FIG. 5 is a diagram illustrating a first example of a drive control method of a registration roll pair and a pre-registration roll pair by a transport system control unit.

FIG. 6 is a diagram illustrating another example of the drive timing of the registration roll pair and the pre-registration roll pair by the transport system control unit.

FIG. 7 is a diagram showing a second embodiment of a positional relationship between a registration roll pair, a pre-registration roll pair, and peripheral members.

FIG. 8 is a diagram showing a third embodiment of a positional relationship between a registration roll pair, a pre-registration roll pair, and peripheral members.

FIG. 9 is a diagram showing a fourth embodiment of the positional relationship between a registration roll pair, a pre-registration roll pair, and peripheral members.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum, 14 ... Registration roll pair, 20 ... Pre-registration roll pair, 40 ... Conveying system control part, 66 ... Drive motor,
Reference numeral 100 ... Image forming unit, 200 ... Conveying unit, 412 ... Nipped state detecting unit, 414 ... Passage amount detecting unit, 416 ... Contact state detecting unit

Claims (7)

[Claims] 1. An upstream-side transport unit, which is disposed on the upstream side of a transport path, sandwiches and transports a sheet-shaped transported object between a pair of rotating bodies, and the upstream side of the transport path. A downstream-side transport unit that is disposed on the downstream side of the side-transport unit, holds the transported object transported by the upstream-side transport unit between a pair of rotating bodies, and transports the transported target further downstream. A transport device that corrects skew distortion of the transported object by driving the upstream-side transportation unit in a normal direction to transport the transported object and abutting the transported object on the downstream transportation unit. Then, the downstream side transport unit is reversely driven at a timing near the tip of the transported body reaches the downstream side transport unit, and after a predetermined time elapses, the downstream side transport unit is released from the reverse rotation drive. A control unit for correcting the skew distortion is provided. That transport device. 2. The control unit reversely drives the downstream side transport unit while maintaining a state in which the transport target body is transported to the downstream side transport unit side by the upstream side transport unit. The transport device according to claim 1. 3. The control section has a sandwiching state detection section for detecting whether or not the transported object is sandwiched by the downstream side transport section, and first stops rotation of the downstream side transport section. A condition that the clamped state detection unit detects that the transport target is transported to the downstream transport unit by the upstream transport unit, and then the transport target is sandwiched by the downstream transport unit. The transport device according to claim 1 or 2, wherein the downstream transport unit is driven in reverse. 4. The control unit includes a passage amount detection unit that detects a passage amount that is an amount passing through the downstream side conveyance unit near the tip of the conveyed body, and first, the downstream side conveyance unit. Is stopped to cause the upstream-side transport unit to transport the transported object toward the downstream-side transport unit, and then the downstream-side transport unit corresponding to the passage amount detected by the passage amount detection unit. Is reversely driven.
The transport device described. 5. The control unit includes an abutting state detection unit that detects whether or not one side, which is a tip of the transported object, abuts the downstream side transportation unit substantially uniformly. The rotation of the downstream-side transport unit is stopped and the upstream-side transport unit transports the transported object to the downstream-side transport unit side, and thereafter, the contact state detection unit causes one side of the transported object to be substantially uniform. The transport device according to claim 1 or 2, wherein the downstream transport unit is reversely driven on condition that it is detected that the downstream transport unit is not in contact with the transport unit. 6. The control unit drives the downstream side transport unit in reverse until the one side of the transported body abuts the downstream side transport unit substantially uniformly based on the detection result of the detection unit. It repeats, The conveyance apparatus in any one of Claim 3 to 5 characterized by the above-mentioned. 7. The upstream side transport unit transports the transported body to the upstream side transport unit side and bends the transported body downstream of a transport path of the upstream transport unit to form a loop. 7. The skew distortion of the transported object is corrected, according to any one of claims 1 to 6.
The transport device according to the item.