JP6763288B2 - Conveyor device, image forming device - Google Patents

Description

The present invention relates to an image forming apparatus in a copier, a printer, a facsimile, or a multifunction device thereof provided with a transfer device and a transfer device.

In a transport device for transporting sheets such as paper, misalignment of the sheets (skew or lateral misalignment) on the transport path may be a problem, and such misalignment of the sheets is corrected and the sheet is predetermined. A transport device for transporting in a direction is already known.

For example, in Patent Document 1 (Japanese Unexamined Patent Publication No. 2016-108152), as shown in FIG. 22, a holding roller 200 is provided which holds the recording medium P and corrects the positional deviation thereof. On the upstream side and the downstream side of the holding roller 200 in the recording medium transport direction, a plurality of photosensors are arranged side by side in the width direction of the recording medium P as detection means for detecting the positional deviation of the recording medium, respectively. (2) CIS202 is provided. Each CIS is provided so as to straddle a position corresponding to the side end of the recording medium P, and by reading the side end position of the recording medium P that has entered the CIS, the lateral deviation amount α of the recording medium P is detected. be able to. Further, the skew amount (skew angle) β of the recording medium can be detected from the difference in the side end positions of the recording medium P detected by the first CIS201 and the second CIS202. Then, based on the detected positional deviation amount of the recording medium P, the sandwiching roller 200 rotates or translates in the width direction while sandwiching the recording medium P to correct the positional deviation amount of the recording medium P. Can be done.

In the above-mentioned detection method of the transport device of Patent Document 1, the skew amount of the recording medium is calculated by simultaneously detecting the recording media by two CIS, and the period during which the skew amount of the recording medium can be detected is recorded. It is limited to the period when the medium faces both CIS. For this reason, when the period in which the recording medium faces the two CIS is short, such as when a small-sized recording medium is conveyed, the accuracy of the correction deteriorates, or there is no period in which the two CIS face each other. In some cases, there is a problem that it cannot be detected by the above method.

Under these circumstances, it is an object of the present invention to provide a transport device capable of accurately correcting the misalignment of a sheet by using the other detection member even in a range where one detection member does not detect the sheet. ..

In order to solve the above problems, the present invention is provided with a sandwiching member that sandwiches and conveys the sheet to the downstream side and corrects the positional deviation, and is provided on the upstream side of the sandwiching member in the sheet conveying direction. In a transport device including an upstream side detecting member for detecting the position of the seat and a downstream side detecting member provided on the downstream side of the sandwiching member in the sheet transporting direction and detecting the position of the sheet, the sandwiching member is the said. Based on the detection results of the sheets of the upstream side detection member and the downstream side detection member, the position deviation of the sheet is corrected, the upstream side detection member does not detect the position of the sheet, and the downstream side detection member is the sheet. In the range of detecting the position of the seat, the position information of the past sheet detected by the downstream detection member is stored, and the sandwiching member determines the position deviation of the sheet actually transported based on the stored position information. It is characterized by correction.

In the present invention, in the process of transporting the sheet, in the range where the upstream detection member does not detect the sheet and the downstream detection member detects the sheet, the position information of the past sheet detected by the downstream detection member is used. Based on this, the sheet transport position is corrected. As a result, the detection result of the past sheet can be substituted for the position deviation within the range not detected by the upstream detection member, and the position deviation correction of the sheet can be performed with high accuracy.

It is a schematic block diagram of an image forming apparatus. It is a schematic block diagram of a transport device. It is sectional drawing which shows the drive mechanism of the holding roller. It is sectional drawing which shows the moving mechanism of a holding frame. It is sectional drawing which shows the drive mechanism of the holding roller. It is sectional drawing which shows the structure of the two-stage spline coupling. It is a figure explaining the state of movement of a holding frame. It is a figure explaining the process of the paper transfer and position correction by a transfer device, (a) is a plan view of a transfer device, and (b) is a side view. It is a figure explaining the process of the paper transfer and position correction by a transfer device. It is a figure explaining the process of the paper transfer and position correction by a transfer device. It is a figure explaining the process of the paper transfer and position correction by a transfer device. It is a figure explaining the process of the paper transfer and position correction by a transfer device. It is a figure explaining the process of the paper transfer and position correction by a transfer device. It is a top view which shows the state which a small size paper is conveyed to a transfer apparatus. It is a figure explaining the detection of the skew amount by the 3rd CIS. It is a block diagram concerning the control operation of a transport device. It is a flow chart of the position correction of the paper using the skew amount of the past paper of this embodiment. It is a figure which shows the correction of the paper using the skew amount of the past paper. It is a flow chart of the position correction of the paper using the skew amount of the past paper of a different embodiment. It is a top view which shows the transport device of a different embodiment. It is a schematic block diagram of the image forming apparatus of a different embodiment. It is a schematic block diagram of the conventional transport device.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and the duplicate description thereof will be appropriately simplified or omitted.

The color image forming apparatus 1 shown in FIG. 1 is provided with an image forming unit 2 to which four process units 9Y, 9M, 9C, and 9Bk are detachably provided. Each process unit 9Y, 9M, 9C, 9Bk accommodates developers of different colors of yellow (Y), magenta (M), cyan (C), and black (Bk) corresponding to the color separation components of the color image. It has the same configuration except that it is.

Specific process units 9 include a photoconductor drum 10 which is a drum-shaped rotating body capable of carrying toner as a developing agent on the surface, and a charging roller which uniformly charges the surface of the photoconductor drum 10. A developing device or the like that supplies toner to the surface of the photoconductor drum 10 is provided.

An exposure unit 3 is arranged above the process unit 9. The exposure unit 3 is configured to emit a laser beam based on the image data.

The transfer unit 4 is arranged directly below the image forming unit 2. The transfer unit 4 includes a drive roller 13, a secondary transfer opposed roller 15, a plurality of tension rollers, an endless intermediate transfer belt 16 stretched by these rollers so as to orbit, and a photoconductor drum of each process unit 9. It is composed of primary transfer rollers 17 and the like arranged at positions facing the intermediate transfer belt 16 with respect to 10. Each primary transfer roller 17 presses the inner peripheral surface of the intermediate transfer belt 16 at each position, and a primary transfer nip is formed at a position where the pressed portion of the intermediate transfer belt 16 and each photoconductor drum 10 come into contact with each other. Has been done.

Further, the drive roller 13 of the intermediate transfer belt 16 and the secondary transfer roller 18 are arranged at positions facing the drive roller 13 with the intermediate transfer belt 16 interposed therebetween. The secondary transfer roller 18 presses the outer peripheral surface of the intermediate transfer belt 16, and a secondary transfer nip is formed at a position where the secondary transfer roller 18 and the intermediate transfer belt 16 come into contact with each other.

The paper feed unit 5 is located at the lower part of the image forming apparatus 1, and carries out the paper feed cassettes 19a to 19d as a plurality of sheet loading units accommodating the paper P as a sheet and the paper P from each paper feed cassette. It is composed of a paper feed roller 20 and the like.

In addition to the paper feed unit 5, a manual feed tray 40 is provided as a sheet loading unit. The paper P loaded on the manual feed tray 40 is fed into the device by the manual paper feed roller 41.

The transport path 6 is a transport path for transporting the paper P carried out from the paper feeding unit 5. A plurality of transport roller pairs are appropriately arranged on the transport path 6 up to the paper ejection portion 8 described later.

On the transport path 6, on the paper transport direction (in the direction of arrow A2 in FIG. 1, hereinafter simply referred to as the transport direction) downstream of the paper feed unit 5, and on the upstream side of the secondary transfer nip position, on the transport path 6. A transport device 30 is provided to correct the misalignment of the paper P in the above direction and transport the paper P to the downstream side.

The fixing portion 7 has a fixing belt 22 that is heated by a heating source, a pressure roller 23 that can pressurize the fixing belt 22, and the like.

The paper ejection unit 8 is provided at the most downstream side of the transport path 6 of the image forming apparatus 1. The paper ejection unit 8 is provided with a pair of paper ejection rollers 24 for ejecting the paper P to the outside and a paper ejection tray 25 for stocking the ejected paper P.

In addition to the most downstream paper ejection path of the transport path 6, an inverted transport path 6b branching from the paper ejection roller 24 is provided. The end of the reverse transfer path 6b joins the transfer path 6 at a position upstream of the transfer device 30 of the transfer path 6. A plurality of transport roller pairs are provided in the middle of the reverse transport path 6b.

A scanner unit 42 is provided above the image forming apparatus 1. The scanner unit 42 can read an image of the surface of the document placed on the contact glass 43.

An ADF (automatic document feeder) 44 is provided above the scanner unit 42. The original placed on the platen of the ADF44 is automatically conveyed to the contact glass 43.

Hereinafter, the basic operation of the image forming apparatus 1 will be described with reference to FIG.

When the image forming operation is started in the image forming apparatus 1, an electrostatic latent image is formed on the surface of the photoconductor drum 10 of each process unit 9Y, 9C, 9M, 9Bk. The image information exposed by the exposure unit 3 on each photoconductor drum 10 is monochromatic image information obtained by decomposing a desired full-color image into yellow, cyan, magenta, and black color information. An electrostatic latent image is formed on each photoconductor drum 10, and the toner stored in each developing device is supplied to the photoconductor drum 10 by a drum-shaped developing roller, so that the electrostatic latent image is visualized. It is visualized as a toner image (developer image).

In the transfer unit 4, the intermediate transfer belt 16 is driven to travel in the direction of arrow A1 in the figure by the rotational drive of the drive roller 13. Further, a constant voltage or a constant current controlled voltage having a polarity opposite to the charging polarity of the toner is applied to each primary transfer roller 17. As a result, a transfer electric field is formed at the primary transfer nip, and the toner images formed on each photoconductor drum 10 are sequentially superposed on the intermediate transfer belt 16 at the primary transfer nip and transferred.

On the other hand, when the image forming operation is started, in the lower part of the image forming apparatus 1, the paper feeding roller 20 of the feeding unit 5 is rotationally driven to drive the paper contained in the paper feeding cassette (for example, the paper feeding cassette 19a). P is sent out to the transport path 6. The paper P can also be sent from the bypass tray 40 to the transport path 6.

The paper P sent out to the transport path 6 is transported to the downstream side by the transport device 30 and the roller pair on the transport path 6, and the misalignment is corrected by the transport device 30, so that the secondary transfer roller 18 and the secondary transfer roller 18 are secondary. It is sent to the secondary transfer nip formed between the transfer opposing roller 15. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 16 is applied, and a transfer electric field is formed in the secondary transfer nip. The toner image on the intermediate transfer belt 16 is collectively transferred onto the paper P by the transfer electric field formed in the secondary transfer nip.

The paper P on which the toner image is transferred is conveyed to the fixing portion 7, and the paper P is heated and pressed by the fixing belt 22 and the pressurizing roller 23 to fix the toner image on the paper P. Then, the paper P on which the toner image is fixed is separated from the fixing belt 22, is conveyed by the transport roller pair, and is discharged to the paper discharge tray 25 by the paper discharge roller 24 at the paper discharge unit 8.

The above description is an image forming operation when forming a full-color image on paper P, but a single-color image can be formed by using any one of four process units 9Y, 9C, 9M, and 9Bk. It is also possible to use two or three process units 9 to form a two-color or three-color image.

Next, a specific configuration of the transfer device 30 for transporting the paper P to the secondary transfer roller 18 on the downstream side and correcting the positional deviation will be described with reference to FIG.

As shown in FIG. 2, the transport device 30 is provided with a straight transport path 6a which is a part of the transport path 6 (see FIG. 1). On the straight transport path 6a, the paper P is sandwiched and conveyed to the downstream side, and the sandwiching roller 31 as a sandwiching member for correcting the positional deviation of the paper P and the upstream in the conveying direction (arrow A2 direction in the figure). From the side, three detection members, a first CIS32, a second CIS33 (upstream side detection member), and a third CIS34 (downstream side detection member) are provided. The sandwiching roller 31 is provided on the downstream side of the second CIS 33 and on the upstream side of the third CIS 34. Further, on the upstream side of the first CIS 32 in the transport direction, a transport roller pair 35 for transporting the paper P is provided. In each CIS, a plurality of photosensors including a light emitting element such as an LED and a light receiving element such as a photodiode are arranged side by side in the width direction of the paper P.

Next, the drive mechanism of the holding roller 31 and the configuration around the drive mechanism will be described with reference to FIGS. 3 to 7.

As shown in FIG. 3, the sandwiching roller 31 is a pair of rollers having a plurality of roller portions divided in the width direction, and is driven by a drive roller 31b that is rotationally driven by a first motor 61 as a first drive means. It is composed of a driven roller 31a that rotates in accordance with the rotation of the roller 31b. The sandwiching roller 31 is configured to be able to convey the sheet P by rotating while sandwiching the sheet P.

The main body frame 70, the base frame 71, the bracket 69, and the like are fixed to each other by screwing, and the holding roller 31 is rotatably supported by the holding frame 72.

The holding roller 31 is formed together with the holding frame 72 as a holding member so as to be rotatable about the support shaft 73 in an oblique direction (double arrow W direction in FIG. 2) and in the width direction (double arrow in FIG. 2). It is formed so that it can move in the H direction). By moving the holding roller 31 in any of the above directions based on the detection result of each CIS, it is possible to correct the skew of the paper P and the positional deviation (horizontal deviation) in the width direction.

The holding frame 72 is formed by forming a sheet metal in a box shape, and the shaft portion of the holding roller 31 is inserted into the holes formed at both ends in the width direction thereof via a bearing. The holding frame 72, together with the holding roller 31, can move in the width direction with respect to the main body frame 70 and the base frame 71, and can rotate about the support shaft 73.

A first drive mechanism composed of a first motor 61, gear trains 66, 67 and the like is connected to one end side of the drive roller 31b in the width direction via a two-stage spline coupling 65. The first drive mechanism transmits the rotational drive force of the first motor 61 to the drive roller 31b via the gear trains 66, 67 and the two-stage spline coupling 65, and rotationally drives the holding roller 31.

Further, on the other end side of the drive roller 31b in the width direction, an encoder 96 for controlling the rotation speed, rotation timing, etc. of the drive roller 31b (holding roller 31) is installed.

As shown in FIG. 6, the two-stage spline coupling 65 includes a first spline gear 65a, a second spline gear 65b, an intermediate spline gear 65c, a guide ring 65d, and the like.

The first spline gear 65a is an external gear and is installed on a rotating shaft 68 that rotates together with one of the gear rows 66 and 67 of the first driving means. The rotating shaft 68 is rotatably held by the bracket 69 via a bearing. Further, the second spline gear 65b is an external gear and is installed on the shaft portion of the drive roller 31b.

The intermediate spline gear 65c is an internal gear, and extends in the width direction so that the holding roller 31 (holding frame 72) meshes with the two spline gears 65a and 65b even if the holding roller 31 (holding frame 72) moves (slides) in the width direction. Has been done. Further, the two spline gears 65a and 65b are formed in a crown shape so as to mesh with the intermediate spline gear 65c even if the holding roller 31 (holding frame 72) rotates in an oblique direction. By using such a two-stage spline coupling 65, even if the holding roller 31 rotates around the support shaft 73 in the substantially horizontal plane direction or slides in the width direction, the frames 69 to 71 of the main body are used. The driving force of the first motor 61 fixedly installed in the motor 61 is accurately and surely transmitted to the driving roller 31b, and the holding roller 31 is satisfactorily rotationally driven.

The guide ring 65d is a substantially annular stopper member, and is an intermediate spline gear in order to prevent the two spline gears 65a and 65b from moving relative to each other in the width direction and falling off from the two-stage spline coupling 65. It is installed at both ends in the width direction of 65c.

Here, as shown in FIG. 5, the holding frame 72 is connected to the frames 69 to 71 via the free bearing 95 (ball transfer) as a relay support member installed on the frames 69 to 71 (base frame 71) of the apparatus. It is movably supported in both the width direction and the oblique direction with respect to (base frame 71) (supported so that it can freely move in a plane orthogonal to the paper surface of FIG. 5).

The free bearing 95 is a known one in which a steel ball 95a is inserted into a recess of the pedestal 95b, and the top of the steel ball 95a comes into point contact with the bottom surface of the holding frame 72. The free bearing 95 is configured to support the holding frame 72 at three or more positions with respect to the frames 69 to 71. In the present embodiment, as shown in FIG. 4, the free bearing 95 corresponds to the four corners on the bottom surface of the holding frame 72. The free bearing 95 is fixed to the base frame 71 at each position (a position where the holding frame 72 can be contacted even if it slides or rotates to the maximum).

By supporting the base frame 71 via the free bearing 95 in this way, even if the holding frame 72 moves in the plane direction relative to the base frame 71, the frictional load generated by the movement is reduced. It can be made extremely small, and the position deviation correction (skew correction and lateral deviation correction) of the paper P can be performed with good responsiveness and high accuracy.

As shown in FIG. 3, a support shaft 73 (stud) is fixed to the bottom surface of the holding frame 72 on the side of the first drive mechanism (on the right side in FIG. 3) so as to stand downward by caulking or the like. ing.

On the other hand, as shown in FIG. 4, a guide portion 71a, which is a rectangular hole portion, is formed on the ceiling surface of the base frame 71 on the side of the first drive mechanism.

As shown in FIGS. 3 and 4, the support shaft 73 is fitted to the guide portion 71a of the base frame 71 via a guide roller 76 rotatably provided on the support shaft 73. Then, the holding frame 72, together with the holding roller 31, can slide and move in the width direction in conjunction with the movement of the support shaft 73 along the guide portion 71a, or can rotate around the support shaft 73.

Further, the holding roller 31 is provided with a second drive mechanism for rotating the holding roller 31 around the support shaft 73 and correcting the skew of the paper P. As shown in FIG. 3, the second drive mechanism includes a second motor 63, a timing belt 98, a first cam 84, a first tension spring 92 as a first urging member (see FIG. 4), a lever member 81, and the like. It is configured.

As shown in FIG. 3, the second motor 63 is fixed to the base frame 71. A timing belt 98 is wound around a drive pulley installed on the motor shaft of the second motor 63 and a driven pulley installed on the rotary support shaft of the first cam 84. The driving force of the second motor 63 is transmitted to the first cam 84 via the timing belt 98.

As shown in FIG. 4, the first tension spring 92 and the holding frame 72 so as to urge the holding frame 72 in the diagonal positive direction (clockwise direction about the support shaft 73 in FIG. 4). It is connected to the base frame 71.

The lever member 81 is rotatably held by the base frame 71 about a rotary support shaft 81a, and a cam follower 82 (first roller-shaped member) abutting on the first cam 84 is rotatably installed on one end side thereof. (Shaft support), and an action roller 83 (second roller-shaped member) that comes into contact with the protrusion 72a of the holding frame 72 is rotatably installed (shaft support) on the other end side.

The first cam 84 is held by the base frame 71 so as to be rotatable about the rotation support shaft 84a. The first cam 84 makes the holding frame 72 urged in the forward direction in the diagonal direction by the first tension spring 92 in the opposite direction in the diagonal direction (counterclockwise direction about the support shaft 73 in FIG. 4). It is indirectly pushed through the lever member 81.

With such a configuration, when the second motor 63 is driven, as shown in FIG. 7A, the rotational driving force is transmitted to the first cam 84 via the timing belt 98, and the first cam 84 Attempts to rotate counterclockwise. The rotational force of the first cam 84 pushes the lever member 81 to rotate around the rotary support shaft 81a, so that the holding frame 72 is pushed by the lever member 81 at the position of the protrusion 72a. The holding frame 72 rotates so as to resist the spring force of the first tension spring 92. By the rotation of the holding frame 72, the holding roller 31 rotates in the direction of the arrow W in FIG. 2 to correct the skew of the paper P.

The first cam 84 and the cam follower 82 are always in contact with each other due to the spring force of the first tension spring 92. Further, the protrusion 72a of the holding frame 72 and the working roller 83 are always in contact with each other, and the holding frame 72 centered on the support shaft 73 depends on the rotation angle (posture in the rotation direction) of the first cam 84. The rotation angle (posture in the rotation direction) of is determined. In this way, the cam follower 82 is installed at the contact position between the first cam 84 and the lever member 81, and the action roller 83 is installed at the contact position between the protrusion 72a and the lever member 81. Since the frictional load generated at the tangent position can be made extremely small, skew correction is performed with good responsiveness and high accuracy.

Further, as shown in FIG. 3, the encoder wheel 86 is installed on the rotary support shaft 84a of the first cam 84, and the encoder sensor 87 is fixedly installed at the position of the base frame 71 corresponding to the encoder wheel 86. Then, the second motor 63 is controlled based on the detection of the encoder wheel 86 by the encoder sensor 87, the rotation angle of the first cam 84 is adjusted and controlled, and the rotation amount of the holding frame 72 is adjusted.

Here, the first cam 84 is formed so that the cam curve becomes a constant velocity cam curve. As a result, the amount of change in the rotation angle of the first cam 84 and the amount of change in the rotation angle of the holding frame 72 can be made proportional to each other, so that the skew correction control of the paper P can be performed with high accuracy. it can.

Further, the holding roller 31 is provided with a third drive mechanism for moving the holding roller 31 in the width direction and correcting the lateral deviation of the paper P. As shown in FIG. 3, the third drive mechanism includes a third motor 62, a timing belt 97, a second cam 74, a second tension spring 91 as a second urging member (see FIG. 4), and the like. ..

As shown in FIG. 3, the third motor 62 is fixed to the base frame 71. A timing belt 97 is wound around a drive pulley installed on the motor shaft of the third motor 62 and a driven pulley installed on the rotary support shaft 74a of the second cam 74. The driving force of the third motor 62 is transmitted to the second cam 74 via the timing belt 97.

As shown in FIG. 4, the second tension spring 91 is connected to the holding frame 72 and the base frame 71 so as to urge the holding frame 72 in the positive direction in the width direction (leftward in FIG. 4). ..

The second cam 74 is held by the base frame 71 so as to be rotatable about the rotation support shaft 74a. The second cam 74 pushes the holding frame 72 urged in the forward direction in the width direction by the second tension spring 91 in the opposite direction (right direction in FIG. 4) in the width direction. A cam follower 75 is installed (shaft support) on the support shaft 73 of the holding frame 72 at a position where it abuts on the second cam 74. Further, a guide roller 76 is installed (shaft support) at a position where the support shaft 73 comes into contact with the guide portion 71a.

With such a configuration, when the third motor 62 is driven, as shown in FIG. 7B, the rotational driving force is transmitted to the second cam 74 via the timing belt 97, and the second cam 74 Attempts to rotate counterclockwise. Due to the rotational force of the second cam 74, the holding frame 72 (pinching roller 31) slides along the guide portion 71a so as to resist the spring force of the second tension spring 91, and the paper P is laterally displaced. It will be corrected.

The spring force of the second tension spring 91 keeps the second cam 74 and the cam follower 75 in constant contact with each other, and the width of the support shaft 73 depends on the rotation angle (posture in the rotation direction) of the second cam 74. The moving distance in the direction is determined. By making the second cam 74 and the support shaft 73 come into contact with each other via the cam follower 75 in this way, the frictional load generated at the contact position can be extremely reduced, so that the lateral displacement correction is responsive. It is often done with high precision.

Further, as shown in FIG. 3, the encoder wheel 77 is installed on the rotary support shaft 74a of the second cam 74, and the encoder sensor 78 is fixedly installed at the position of the base frame 71 corresponding to the encoder wheel 77. Then, the third motor 62 is controlled based on the detection of the encoder wheel 77 by the encoder sensor 78, the rotation angle of the second cam 74 is adjusted and controlled, and the amount of movement of the holding frame 72 in the width direction is adjusted.

Here, the second cam 74 is formed so that the cam curve becomes a constant velocity cam curve. As a result, the amount of change in the rotation angle of the second cam 74 and the amount of change in the moving distance of the holding frame 72 can be made proportional to each other, so that the lateral displacement correction control of the paper P can be performed with high accuracy. it can.

FIG. 7C is a diagram showing an example of the operation of the holding frame 72 when the lateral deviation correction and the skew correction of the paper P described above are performed at the same time.

As shown in FIG. 7C, when the second motor 63 is driven to rotate the first cam 84, the lever member 81 is pushed by the first cam 84 and rotates about the rotation support shaft 81a. As a result, the holding frame 72 is pushed by the lever member 81 at the position of the protrusion 72a, and the holding frame 72 rotates so as to resist the spring force of the first tension spring 92. At the same time, when the third motor 62 is driven to rotate the second cam 74, the holding frame 72 slides and moves by the second cam 74 so as to resist the spring force of the second tension spring 91. At this time, the action roller 83 of the lever member 81 pushes the protrusion 72a (holding frame 72) while moving on the surface of the protrusion 72a.

Next, a method of calculating the lateral deviation amount α and the skew amount β on the transport path of the paper P by each CIS will be described with reference to FIG.

As shown in FIG. 2, when each CIS faces the paper P, each CIS detects the position of the side edge Pb of the paper P, so that the ideal position in the width direction of the side edge of the paper P (parallel lines in the figure). The distance from L) can be calculated as the lateral deviation amount α (in the illustrated example, the positional deviation amount at the position of the tip Pa of the paper P).

Further, the skew amount β of the paper P is calculated from the difference in the positions of the side edge Pb detected by the two CIS. That is, as shown in FIG. 2, when the paper P is conveyed to a position facing the first CIS 32 and the second CIS 33, the first CIS 32 and the second CIS 33 detect the position in the width direction of the side end Pb, respectively. .. Then, the position in the width direction of the side end Pb detected by the first CIS 32 is L1, and the position in the width direction of the side end Pb detected by the second CIS 33 is L2, and the first CIS 32 and the second CIS 33 measured in advance are set. The skew amount β can be calculated by tan β = (L2-L1) / d, where the distance is d. The second CIS 33 and the third CIS 34 can also calculate the lateral deviation amount α and the skew amount β by the same method.

In the present embodiment, the holding roller 31 has two positional deviation amounts, that is, the position deviation amount (horizontal deviation amount) in the width direction of the paper and the inclination (oblique amount) with respect to the paper transport direction calculated as described above. The misalignment is corrected based on. Hereinafter, the operation of the holding roller 31 for correcting the misalignment of the paper P will be described with reference to FIGS. 8 to 13. As shown in FIG. 8B, a detection sensor 36 for detecting that the paper P has reached the secondary transfer position is provided immediately before the secondary transfer nip.

As shown in FIGS. 8A and 8B, when the paper P is carried into the transport device 30, the transport roller pair 35 first sandwiches the paper P and transports the paper P to the downstream side. Then, when the paper P moves to a position facing each CIS, the lateral deviation amount α1 of the paper P is detected.

Further, when the paper P is conveyed to the positions facing the first CIS 32 and the second CIS 33, the skew amount β1 of the paper P is detected by the two CIS by the above-mentioned method. It is also possible to obtain the amount of misalignment of paper P by detecting the amount of misalignment of paper P a plurality of times and statistically processing the detection result, and one detection result is used as the amount of misalignment of paper P. You can also do it.

As shown in FIGS. 9A and 9B, the pinching roller 31 is rotated with its rotation center W0 centered in the width direction of the pinching roller 31 with reference to the center position in the width direction of the paper P. Move. By this rotation operation, the holding roller 31 can correct the skew (inclination with respect to the conveying direction) of the paper P when the paper P is held. Further, the holding roller 31 can slide and move in the width direction of the paper P, and can correct the lateral deviation of the paper P.

When the positional deviation amount of the paper P (horizontal deviation amount α1 and skew amount β1) is calculated by the first CIS 32 and the second CIS 33, the holding roller 31 corrects the paper P in advance before holding the paper P. The paper P is moved in the direction opposite to the direction in which the paper P is displaced by the amount of misalignment. Specifically, the holding roller 31 rotates in the direction of the arrow W1 by an angle β1 and translates in the direction of the arrow H1 by a distance α1 (hereinafter, this operation is referred to as an welcoming operation).

By this picking operation, the holding roller 31 can hold the paper P in a state of facing the paper P, and the positional deviation of the paper P when the holding roller 31 holds the paper P can be reduced as much as possible.

As shown in FIGS. 10 (a) and 10 (b), when the paper P is conveyed to a position facing the sandwiching roller 31, the sandwiching roller 31 sandwiches the sheet P and the transfer roller pair 35 is transferred from the sheet P. Separate.

As shown in FIGS. 11 (a) and 11 (b), the holding roller 31 holding the paper P corrects the misalignment of the paper P while transporting the paper P to the downstream side. Specifically, the holding roller 31 rotates in the arrow W2 direction and translates in the arrow H2 direction based on the amount of positional deviation detected by each CIS. As a result, the paper P moves from the original position (two-dot chain line portion in the figure) to the corrected position (solid line portion in the figure), and the positional deviation is corrected (hereinafter, this operation is referred to as a feed operation). ..

In this way, the misalignment of the paper P can be corrected by the picking operation and the feeding operation (first correction operation) by the holding roller 31. Further, by causing the holding roller 31 to perform the picking operation in advance, the holding roller 31 after the feeding operation is held in the reference posture of the holding roller 31 (the posture of the solid line portion in FIG. 11a, which faces the transport path of the paper P). Can be placed in.

As shown in FIGS. 12A and 12B, when the paper P is conveyed further downstream by the holding roller 31, the paper P faces the third CIS 34. Then, the lateral deviation amount α2 and the skew amount β2 of the paper P are detected by the second CIS33 and the third CIS34. Based on the amount of the misalignment of the paper P, the holding roller 31 rotates and moves in parallel, and the misalignment of the paper P is corrected again (hereinafter, this operation is referred to as a second correction operation).

By performing such a second correction operation, the misalignment of the paper P can be corrected with higher accuracy. That is, in the first correction operation, the misalignment of the paper P detected by the first CIS32 and the second CIS33 before the pick-up operation can be corrected, but the misalignment of the paper P after that can be corrected. Can not. Therefore, by performing the second correction operation after the first correction operation, it is possible to correct the position deviation of the paper P after that, and it is possible to realize a highly accurate correction. The main causes of the misalignment of the paper P after first detecting the misalignment of the paper P are the transport skew of the transport roller vs. 35, the difference in parallelism with the pinching roller 31, and the pinching roller 31 of the paper. Examples include fluttering of the paper P due to pressurization when holding P, pressure deviation in the width direction of the holding roller 31, and transfer skew of the holding roller 31.

During the second correction operation, the position deviation of the paper P is repeatedly detected by the second CIS 33 and the third CIS 34, and the position correction amount of the paper P is corrected each time and fed back to the moving amount of the holding roller 31. That is, as described above, the misalignment of the paper P also occurs during the position correction of the paper P (while the paper P is being conveyed), and the amount of the misalignment of the pinching roller 31 is detected every moment to detect the misalignment of the pinching roller 31. By feeding back to the correction amount of, the amount of positional deviation of the paper P to the downstream side in the transport direction can be corrected, and more accurate correction can be realized.

Then, as shown in FIGS. 13 (a) and 13 (b), after the second correction operation of the paper P, the paper P is further conveyed to the downstream side, and when it reaches the secondary transfer position, the holding roller 31 moves. Separate from the paper P. Then, at the secondary transfer position, the image is transferred to the paper P, and the paper P is conveyed further downstream. At this time, the detection sensor 36 detects the arrival of the paper P at the secondary transfer position, and the transport device 30 shifts to the operation for transporting the next paper.

As described above, in the transport device 30 of the present embodiment, in the transport process of the paper P, the position shift amount of the paper P can be calculated by each CIS, and the position shift can be corrected by the holding roller 31. In particular, in the present embodiment, the transport device 30 is arranged immediately before the secondary transfer position, and the misalignment of the paper P in the secondary transfer nip can be minimized, and the intermediate transfer belt 16 (see FIG. 1). It is possible to minimize the misalignment of the image transferred from the paper to the paper P.

By the way, the size of the paper on which the image forming apparatus 1 forms an image is various, and the conveying device 30 is also required to correspond to the papers of various sizes. For example, the postcard-sized paper P1 as shown in FIG. 14 is passed through the transport device 30.

When the small-sized paper P1 is passed through the conveying device 30, the problem is that the range in which the amount of misalignment of the paper P can be detected is narrower than that of the large-sized paper. That is, as shown in FIG. 14, in the small size paper P1, the rear end Pc of the paper P passes through the second CIS 33 at an earlier stage than the large size paper, so that the second CIS 33 and the third CIS 34 The period facing the computer is short. Therefore, in the section where the paper P reaches the secondary transfer position from the position shown in FIG. 14, the paper P cannot be detected by the two CIS, and the misalignment of the paper P that occurs in this section is corrected. This may not be possible, or the number of data of the amount of misalignment of the paper that can be acquired by the second CIS 33 and the third CIS 34 may decrease, which affects the accuracy of the position correction.

In order to solve the above problems, in the transport device of the present embodiment, the following control is performed when a small size paper is transported.

First, as shown in FIG. 14, after the rear end Pc of the paper P1 has passed through the second CIS 33 (after the paper P1 is no longer detected by the second CIS 33), the paper P1 is formed by the third CIS 34 facing the paper P1. The position of the side end Pb of the above is detected and recorded a plurality of times at regular intervals.

The skew amount β of the paper P1 can be calculated from the plurality of detection positions having different detection times. Specifically, as shown in FIG. 15, the side end Pb portion of the paper P1 facing (detected) the third CIS 34 at a certain time is positioned at the side end portion Pb1 and the side end portion Pb1 at the width direction position. Let M1 be the side end Pb2 of the paper P1 facing the third CIS34 t seconds after a certain time, the width direction position of the side end Pb2 be the position M, and the transport speed of the paper P1 be v. Then, the skew amount β of the paper P1 can be obtained by tan β = (M1-M2) / pt. The skew amount β (position information) of the paper P1 obtained in this way is stored in the storage unit of the image forming apparatus.

Then, when a small-sized paper is passed through the transport device 30, the skew of the paper that is actually passed is determined based on the skew amount β (past position information of the paper) of the paper P1 described above. Correct the line. That is, in addition to the first correction operation of the paper that is actually passed and the second correction operation until the rear end of the paper passes through the second CIS33, the paper that has been conveyed in the past is detected and obtained. The correction is performed based on the amount of skew (hereinafter, also simply referred to as the amount of skew of past paper).

As the correction amount based on the skew amount of the past paper, it is preferable to determine the correction amount by statistically processing the detection results of a plurality of times. This eliminates error factors such as individual detection errors and enables accurate correction. Further, the correction amount may be determined by statistically processing the detection result data of a plurality of sheets of paper. As a result, it is possible to eliminate as much as possible the factors of misalignment peculiar to each paper such as the habit of each paper, and it is possible to perform more accurate correction. However, it is possible to detect the skew amount of the past paper only once and use it as the correction amount. In this case, it is preferable to use the amount of skew immediately before the paper reaches the secondary transfer position. As a result, it is possible to correct the amount of skew from the time when the paper passes through the second CIS 33 to just before reaching the secondary transfer position.

In this way, by substituting the skew amount of the paper detected by the third CIS34 in the past in the range where the paper P cannot be detected by the second CIS33, the paper P is generated by just before reaching the secondary transfer position. Positional deviation can be corrected, and more accurate correction becomes possible.

In the correction using the skew amount of the past sheet (paper), the skew amount of the sheet is memorized for each type of sheet to be conveyed (plain paper, cardboard, envelope, etc.), sheet size, and thickness. It is preferable to make corrections using the amount of skew of the past sheets corresponding to the type, size, and thickness of the sheets actually transported. As a result, the positional deviation can be corrected by the correction amount according to each type of sheet, so that more accurate correction becomes possible. Further, it is determined which of the sheet loading sections of the paper feed cassettes 19a to 19d and the manual feed tray 40 is supplied, and the past sheet skew amount data is stored for each sheet loading section, and the paper is actually conveyed. It may be corrected by using the past data corresponding to the paper feed cassette or the like on which the sheet to be loaded is loaded.

Further, it is determined whether the paper actually transported is the front side printing or the back side printing, and the skew amount of the past paper detected in the corresponding printing surface transfer process is used. It is preferable to perform skew correction. Since the paper transport path is different between the front surface transport and the back surface transport, the skew amount is also different. Therefore, it is possible to perform more accurate correction by correcting using different skew amounts. it can.

The skew amount of the past paper used for the correction may be measured by providing a measurement mode for measuring the skew amount in advance. As a result, it is possible to perform correction using the skew amount of the past paper described above from the first paper passed through the transport device. Further, the first passed paper may be used for the next and subsequent corrections by only detecting and storing the skew amount without performing the correction using the skew amount of the past paper. With respect to these methods, the operator may be set to select the presence or absence of the measurement mode by using the operation panel of the image forming apparatus or the like. Further, even in the measurement mode, a plurality of sheets of paper are conveyed, the skew amount is detected and stored, and the stored skew amount is statistically processed to correct the amount of the actually conveyed paper. It is preferable to determine.

In addition, the skew amount of the past paper used for correction is the skew amount measured in advance by the measurement mode, the skew amount obtained by measuring the paper passed in the first stage, and then the skew amount. It can be used continuously, or the skew amount may be detected by the third CIS34 each time the paper is conveyed, and the stored past paper skew amount data may be updated each time.

Further, each time the control unit of the image forming apparatus detects the opening / closing of the paper feed cassettes 19a to d (see FIG. 1), the data of the past skew amount of the type of paper corresponding to the paper feed cassette is initialized. , It is also possible to newly set the data of the skew amount of the paper. When the paper cassette is opened and closed, it is highly possible that a new bundle of paper has been set in the paper cassette, and due to changes in the arrangement and orientation of the paper bundle in the paper cassette, changes in paper habit, etc. , There is a high possibility that trends such as the amount of skew of paper and the direction of skew will change. For this reason, by initializing the data of the skew amount of the past paper at the timing of opening and closing the paper cassette and setting it to take a new one, it is possible to make a correction according to the tendency of the new paper, and the accuracy of the correction. Can be improved.

It is also possible to set the image forming apparatus to be turned off once and restarted to initialize the data of the skew amount of the past paper and to take a new one. Even if the paper feed cassette is opened and closed while the power supply of the image forming apparatus is stopped, the control unit of the image forming apparatus cannot detect the opening and closing. Therefore, when the power supply of the image forming apparatus is stopped and restarted. Can be set to newly correct the skew amount of the paper.

FIG. 16 is a block diagram showing control of operations related to the transport device 30.
As shown in FIG. 16, when the controller 54 outputs a drive signal to the motor driver 55, the motor driver 55 drives each motor provided in the transfer device 30, and the rotation operation of the holding roller 31 and the rotation of the transfer roller pair 35 Drive control such as operation is performed.

Further, the correction amount of the paper is determined by the arithmetic circuit 53 based on the detection result of each CIS of the transport device 30. A drive signal is output from the controller 54 according to this correction amount, the second motor 63 and the third motor 62 are driven, and the holding roller 31 rotates or slides to correct the misalignment of the paper.

When the operation panel 52 is operated by an operator, the information is sent to the main body control unit 50 provided on the main body side of the image forming apparatus 1. Specifically, information such as the type of paper used for image formation and the presence / absence of a measurement mode for measuring the skew amount data of the past paper is sent to the main body control unit 50.

When the image forming operation is started, information such as the size of the paper used for image forming is referred to, and data on the skew amount of the past paper is sent from the storage unit 51 to the controller 54 side for the corresponding paper. .. The misalignment of the paper is corrected based on the amount of skew of the paper in the past. Further, the past misalignment amount of the paper detected by the third CIS 34 is stored in the storage unit 51.

The main body control unit 50 detects the opening / closing operation of the paper feed cassette 19, and initializes (deletes) the data of the amount of past paper misalignment stored in the storage unit 51 for the corresponding paper feed cassette 19.

The control flow of the second correction operation of the present embodiment is shown in FIG.
As shown in FIG. 17, when a print command is first issued to the image forming apparatus 1, the control unit confirms the information (sheet type, size, etc.) of the paper P carried into the conveying apparatus 30 (step S1). .. Then, it is determined whether or not the data of the skew amount of the past paper matching the paper P to be carried in exists in the storage unit (step S2), and if the data of the skew amount of the past exists, it is determined. The data is referred to from the storage unit, and the target position of the sandwiching roller 31 is determined based on the data of the skew amount (step S3).

Then, the actual skew amount of the paper P actually conveyed by the second CIS 33 and the third CIS 34 is detected (step S4), and the skew amount is corrected by the rotational operation of the holding roller 31 (step S5). ). This skew amount detection operation is repeated until the rear end Pc of the paper P passes through the second CIS 33. That is, each time the second CIS 33 and the third CIS 34 detect the skew amount, the rotation amount by the holding roller 31 is corrected. By the feedback control by this repeated detection, it is possible to correct the misalignment of the paper P during the correction operation, and it is possible to perform the correction with higher accuracy.

Here, the details of the skew correction of the paper P in steps S3 to S6 will be described with reference to FIG. In the example of FIG. 18, the correction amount was determined to be the rotation of the angle β3 clockwise based on the data of the skew amount of the past paper referred to from the storage unit.

The paper P before the second correction operation is shown on the right side of FIG. 18, and the paper P is tilted counterclockwise by an angle β4 with respect to the transport direction.

The pinching roller 31 rotates in the direction of the arrow W2 by the second correction operation, and corrects the detected skew of the paper P. At this time, if there is no data on the amount of skew of the past paper, the paper P is rotated to an ideal position facing the transport path. On the other hand, when there is data on the skew amount of the past paper, the paper P is rotated from the ideal position by the determined correction amount. Specifically, as shown in the center of FIG. 18, since the determined correction amount was the rotation of the angle β3 clockwise, the paper P was tilted clockwise by the angle β3 from the position facing the transport path. Rotate to the correct position. That is, from the data of the skew amount of the past paper, the paper P may be tilted counterclockwise by an angle β3 from the position where it passed through the second CIS33 (see FIG. 14) until it is conveyed to the secondary transfer nip. is assumed. Therefore, by moving in advance to a position tilted by an angle β3 in the opposite direction, the paper P can be brought closer to the ideal position in front of the secondary transfer roller 18 as shown on the left side of FIG. 18 (past). If it is tilted by the same amount as the paper in, it can be placed in the ideal position).

In this way, the correction amount determined based on the skew amount of the past paper is added to the correction amount of the second correction operation (the amount of rotation to the ideal position of the paper) at the time of the second correction operation. The correction is made. Further, the correction using the skew amount of the past paper is not limited to the second correction operation, and can be performed at a predetermined timing while the holding roller 31 is holding the paper P, such as during the feed operation.

Then, as shown in FIG. 17, the position deviation of the paper P that has completed the second correction operation and passed through the second CIS 33 is detected by the third CIS 34, and the detection data is stored (step S7, S8). Then, the detection by the third CIS 34 is repeated until the paper P reaches the secondary transfer roller 18 (step S9).

The data of the amount of misalignment of the paper P stored in step S8 is stored as a value corrected by the amount of the target movement amount determined in step S2. That is, the paper P in step S7 is tilted by the amount of skew in the direction opposite to the tilt direction based on the data of the skew amount of the past paper (second correction operation in step S5). .. For example, in the example of FIG. 18, it is tilted clockwise by an angle β3. Therefore, the value excluding the angle β3 is stored in the storage unit as the skew amount of the past paper.

Then, when the detection sensor 36 (see FIG. 8b) detects that the paper P has reached the secondary transfer roller 18, the detection of the positional deviation by the third CIS34 is completed, and the detection result by the third CIS34 is statistically processed. Then, the correction value using the skew amount of the past paper is determined (step S10).

Then, when there is a print command for the next sheet, the transfer device shifts to the next operation (step S11).

By the above steps, even if the paper to be carried in is a small size paper, the transport device 30 can transport the paper to the downstream side while accurately correcting the misalignment of the paper.

In the above description, the case where the skew amount of the past paper is updated every time the transport device conveys new paper has been described. On the other hand, FIG. 19 shows a flow chart in the case where the skew amount of the past paper is not updated and the correction amount determined first is used as it is.

As shown in FIG. 19, in the flow of the present embodiment, when the rear end of the paper P passes through the second CIS 33 (step S6), the difference from the flow diagram shown in FIG. 17 is that the past paper P is skewed. The determination of whether or not the amount of data exists is performed again (step S6b). Then, when there is data on the skew amount of the past paper P and the correction amount has already been determined, the tip of the paper is not detected by the third CIS34 in steps S7 to S10 and the correction amount is not determined. When the detection sensor 36 detects that the data has reached the secondary transfer roller (step S7c), the transport device shifts to the next paper transport operation.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

Sheets include paper P (plain paper), thick paper, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, transparencies, plastic films, prepregs, copper foil, etc. included.

As shown in FIG. 20, a pair of skew detection sensors 37 may be provided on the downstream side of the third CIS 34 and immediately before the secondary transfer roller 18. Thereby, the skew amount of the paper P immediately before reaching the secondary transfer nip can be detected. By using this detection result as the skew amount of the past paper and performing the skew correction of the paper actually transported, more accurate correction becomes possible.

The image forming apparatus according to the present invention is not limited to the color image forming apparatus shown in FIG. 1, and may be a monochrome image forming apparatus, a copying machine, a printer, a facsimile, or a combination machine thereof.

Further, in the embodiment described above, the present invention has been applied to the transfer device 30 installed in the electrophotographic image forming device 1, but to the transfer device installed in the inkjet image forming device. The present invention can also be applied. Hereinafter, an inkjet type image forming apparatus will be described with reference to FIG.

As shown in FIG. 21, the inkjet type image forming apparatus 100 includes a feeding unit 110, a conveying device 120, an image forming unit 130, a drying unit 140, and a paper ejection unit 150.

The paper P sent out from the paper feeding unit 110 is conveyed by the conveying device 120 and sent out to the image forming unit 130.

In the image forming unit 130, the paper P is positioned on the cylindrical drum 131, and is conveyed in the direction of the arrow in the drawing by the rotation of the cylindrical drum 131. Then, the paper P is conveyed to the lower portion of the ejection head 132 of each color at a predetermined timing, the ink of each color is discharged to the paper P, and an image is formed on the surface of the paper P.

The paper P on which the image is formed by the image forming unit 130 is conveyed to the drying unit 140 to evaporate the moisture in the ink, and then is discharged to a position where the operator can take it out at the paper ejection unit 150.

By applying the configuration of the transport device of the present invention described above to the transport device 120, the same effect as that of the present embodiment described above can be obtained. That is, the paper P can be conveyed to the image forming unit 130 side, the misalignment of the paper P on the conveying path can be corrected with high accuracy, and the image can be formed at the regular position of the paper P.

Further, in the embodiment described above, the case where the small size paper is corrected based on the data of the skew amount of the past paper is shown, but the large size paper may be used.

Further, in the embodiment described above, the range in which the paper P does not face the second CIS 33 and the second CIS 33 cannot detect the paper P is corrected by using the data of the skew amount of the past paper by the third CIS 34. Was supposed to be done. However, the correction may be performed using the data of the skew amount of the past paper by the third CIS34, for example, in the range where the accuracy of the detection by the second CIS33 is lowered, not limited to the range that cannot be detected by the second CIS33. ..

In the embodiment described above, the storage unit for storing the skew amount of the past paper and the like is provided on the main body side of the image forming apparatus 1, but the storage unit may be provided on the side of the conveying device.

Further, in the above description, the case where the lateral deviation amount and the skew amount of the paper are detected by each CIS and corrected thereof has been shown, but only one of the positional deviations may be corrected.

1 Image forming device 18 Secondary transfer roller 30 Transfer device 31 Holding roller (holding member)
32 First CIS
33 Second CIS (upstream detection member)
34 Third CIS (downstream detection member)
19a to d Paper feed cassette (sheet loading section)
40 Manual feed tray (seat loading section)

Japanese Unexamined Patent Publication No. 2016-108152

Claims (10)

A holding member that holds the sheet and conveys it to the downstream side and corrects the misalignment.
An upstream detection member provided on the upstream side of the sandwiching member in the sheet transport direction and detecting the position of the sheet, and an upstream detection member.
In a transport device provided on the downstream side of the sandwiching member in the sheet transport direction and provided with a downstream side detection member for detecting the position of the seat.
The sandwiching member corrects the misalignment of the sheet based on the detection results of the sheet of the upstream detection member and the downstream detection member.
In the range where the upstream side detecting member does not detect the position of the sheet and the downstream side detecting member detects the position of the sheet, the position information of the past sheet detected by the downstream side detecting member is stored.
A transport device, wherein the sandwiching member corrects a misalignment of a sheet that is actually transported based on the stored position information. The stored position information of the sheet is composed of a plurality of position information of the plurality of sheets transported in the past, and the sandwiching member is the sheet by a correction amount obtained by statistically processing the plurality of position information. The transport device according to claim 1, wherein the misalignment of the above is corrected. The sandwiching member is based on the position information of a past sheet having a type, size, or thickness corresponding to at least one of the types, sizes, and thicknesses of the sheets actually transported. The transport device according to claim 1 or 2, wherein the misalignment of the sheet actually transported is corrected. The transfer device according to any one of claims 1 to 3, wherein the correction amount based on the stored position information of the sheet is updated every time a new sheet is conveyed. A measurement mode for storing the position information is provided.
The transport device according to any one of claims 1 to 4, wherein the sandwiching member corrects a misalignment of a sheet that is actually transported based on the position information stored in the measurement mode. The sheet is supplied from one of a plurality of sheet loading sections for loading the sheet.
Any one of claims 1 to 5 for correcting the misalignment of the currently transported sheet based on the position information of the past sheet supplied from the same sheet loading unit as the sheet loading unit that supplied the actually transported sheet. The transport device according to item 1. A transport device provided in an image forming device capable of double-sided printing.
The position information of the past sheet is stored individually for each of the front side printing and the back side printing.
The sandwiching member is any one of claims 1 to 6 that corrects the misalignment of the sheet actually transported based on the position information of the past sheet on the printed surface corresponding to the printed surface of the sheet actually transported. The transport device according to. A transport device provided in an image forming device capable of forming an image on the sheet.
The sheet is supplied from a sheet loading unit that can be opened and closed with respect to the image forming apparatus main body.
Every time the seat loading unit is opened and closed, the stored position information of the past seat is initialized.
The transport device according to any one of claims 1 to 7, wherein the sandwiching member corrects a misalignment of a sheet that is actually transported based on the position information of the sheet after opening and closing. A transport device provided in an image forming device capable of producing an image on the sheet.
Each time the power of the image forming apparatus is stopped and started, the position information of the past stored sheet is initialized, and the position information of the past sheet is initialized.
The transport device according to any one of claims 1 to 8, wherein the sandwiching member corrects the misalignment of the sheet that is actually transported based on the position information of the sheet after the power supply of the image forming apparatus is stopped and started. .. An image forming apparatus including the transport device according to any one of claims 1 to 9.

Images