JP2017202916A - Sheet-like object transportation device and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform inviting operation of a pinch roller according to a change even if a position deviation amount of the sheet-like object changes after detection thereof.SOLUTION: A sheet-like object transportation device includes a pinch roller 33 for correcting position deviation amount of a sheet-like object P by performing inviting operation and returning operation corresponding to the position deviation amount of the sheet-like object P. A drive part (120, 130) which performs inviting operation and returning operation of the pinch roller 33 is controlled by a control part 160. At a detection part (145, 146, 147), on an upper stream side of the pinch roller 33, the position deviation amount of the sheet-like object is detected at least twice, and the detected position deviation amount is accumulated in a storage accumulation part 156. Based on a first position deviation amount S1 of a first detection by the storage accumulation part 156, the drive part (120, 130) is controlled at a first step for performing a first inviting operation of the pinch roller 33. Based on a differential position deviation amount (S1-S2) between the first position deviation amount S1 and the second position deviation amount S2 at the second detection by the storage accumulation part 156, the drive part (120, 130) is controlled at a second step for performing second inviting operation of the pinch roller 33.SELECTED DRAWING: Figure 8A

Description

The present invention relates to a sheet-like material conveying device that performs skew correction and lateral registration correction of a sheet-like material conveyed along a conveying path, a copying machine, a printer, a facsimile, or a complex machine including the conveying device. The present invention relates to an image forming apparatus such as an offset printing machine.

In image forming apparatuses such as copying machines and printers, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2014-088263), Patent Document 2 (Japanese Patent Laid-Open No. 10-67448), and Patent Document 3 (Japanese Patent No. 4324047) are used. In addition, the nipping roller disposed in the sheet conveyance path is moved in the inclination direction and the width direction with respect to the conveyance path to correct skew and lateral misregistration of the sheet sheet (in the sheet width direction). (Misalignment correction) is performed.

In the apparatuses disclosed in Patent Documents 1 to 3, the skew angle and the lateral misregistration amount of the sheet-like body are detected by a skew sensor and a lateral registration sensor arranged on the upstream side of the sandwiching roller. After this detection, the skew angle and the amount of lateral misregistration may further change until the sheet-like body reaches the clamping roller. The correction (correction) accuracy of the skew angle and the lateral registration amount is generally required to be highly accurate with a skew angle of 0.1 mrad level and a lateral registration amount of several tens of μm level. Therefore, even if the amount of change in the skew angle and the lateral registration amount is slight, the correction accuracy of the sheet-like body cannot be guaranteed.

However, if the distance between the sandwiching roller and the upstream skew sensor and lateral registration sensor is shortened, the amount of change after the aforementioned skew and lateral registration detection can be reduced. However, when the distance is shortened, the operation time of the nipping roller after the skew / lateral registration detection is shortened, and the correction moving speed of the nipping roller is increased in inverse proportion to the operation time. If it does so, when a sheet-like object will be conveyed at high speed, a pinching roller will vibrate easily, and the subject that it becomes easy to generate | occur | produce the shading of a periodic image called banding occurs.

The present invention detects the skew angle and the lateral misregistration amount of the sheet-like body again before the sheet-like body reaches the clamping roller even if the skew angle and the lateral misregistration amount of the sheet-like body change after the initial detection. Thus, an object is to cope with changes in the skew angle and the lateral misregistration amount after the first detection of the sheet-like body. It is another object of the present invention to prevent banding by suppressing vibration due to the correction operation of the clamping roller even when the sheet-like body is conveyed at high speed.

In order to solve the above-mentioned problem, the present invention conveys the sheet-like body along a predetermined conveyance path in a state where both surfaces of the sheet-like body are sandwiched, and operates to meet the positional deviation amount of the sheet-like body. And in the sheet-like material transport apparatus having a sandwiching roller that corrects the positional deviation amount of the sheet-like member by performing the return operation, the sheet is disposed on the upstream side of the sandwiching roller, and is immediately upstream of the sandwiching roller. A detecting unit that detects a positional deviation amount of the sheet-like body at least twice until the sheet-like body reaches the clamping roller; and a storage accumulation unit that stores and accumulates the positional deviation amount detected at least twice by the detecting unit. Based on the drive unit that picks up and returns the pinching roller and the first position shift amount S1 of the first detection obtained from the memory storage unit, The drive unit is controlled in a first stage, and a difference position shift amount between the second position shift amount S2 of the second detection obtained from the storage accumulation unit and the first position shift amount S1 of the first detection ( And a control unit that controls the driving unit in a second stage to perform the second pick-up operation of the nipping roller based on S2-S1).

According to the present invention, a control unit that controls a drive unit that tilts the pinching roller performs a first pick-up operation on the pinching roller based on the first positional shift amount S1 of the first detection obtained from the storage accumulation unit. Therefore, the drive unit is controlled in the first stage, and the difference position shift amount between the second position shift amount S2 of the second detection obtained from the storage accumulation unit and the first position shift amount S1 of the first detection ( Based on S2-S1), the drive unit is controlled in the second stage to perform the second pick-up operation of the clamping roller, so that the positional deviation amount of the sheet-like body is from the first detection to the second detection. Even if it changes between them, the positional deviation of the sheet-like body can be eliminated by operating and returning the nipping roller in response to the change in the positional deviation amount. In addition, since the drive unit that picks up and returns the nipping roller is controlled at least in the first stage control and the second stage control, vibration of the nipping roller is suppressed even when the sheet-like body is conveyed at high speed. Banding can be prevented.

1 is an overall configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is an enlarged view showing an image forming unit of the image forming apparatus. 1 is a schematic diagram showing an intermediate transfer belt device of an image forming apparatus and its periphery. BRIEF DESCRIPTION OF THE DRAWINGS The outline of the sheet-like object conveying apparatus which concerns on embodiment of this invention is shown, (a) is a top view, (b) is a side view. It is sectional drawing of the sheet-like object conveying apparatus which concerns on embodiment of this invention. It is a BB line arrow top view of Drawing 5A. (A)-(d) is a figure which shows the horizontal registration correction | amendment operation | movement and skew correction | amendment operation | movement of a roller holding member. FIG. 6 is a diagram illustrating a lateral registration correction amount Δy and a skew correction amount Δx of a roller holding member. The skew correction error of the sheet-like body conveyance device will be described, wherein (a) is a top view before skew correction, and (b) is a side view before skew correction. The skew correction error of the sheet-like material conveyance device will be described, wherein (a) is a top view after skew correction, and (b) is a side view after skew correction. It is a figure which shows the flowchart of a sheet-like body conveying apparatus. It is a figure which shows the modification of the flowchart of a sheet-like body conveying apparatus. It is a figure which shows the modification of the flowchart of a sheet-like body conveying apparatus. The first stage of sheet conveyance is shown, (a) and (b) are top views, and (c) is a side view. The second stage of sheet conveyance is shown, (a) is a top view and (b) is a side view. The third stage of sheet conveyance is shown, (a) is a top view and (b) is a side view. The fourth stage of sheet conveyance is shown, (a) is a top view and (b) is a side view. The fifth stage of sheet conveyance is shown, (a) is a top view and (b) is a side view. The sixth stage of sheet conveyance is shown, wherein (a) is a top view and (b) is a side view. The seventh stage of sheet conveyance is shown, (a) is a top view and (b) is a side view. The eighth stage of sheet conveyance is shown, wherein (a) is a top view and (b) is a side view. The ninth stage of sheet conveyance is shown, (a) is a top view and (b) is a side view. The tenth stage of sheet conveyance is shown, (a) is a top view, and (b) is a side view. The 11th stage of sheet conveyance is shown, (a) is a top view, (b) is a side view. The twelfth stage of sheet conveyance is shown, (a) is a top view, and (b) is a side view. The modification of the skew detection sensor of a sheet-like body conveyance apparatus is shown, (a) is a top view before skew detection, (b) is a side view before skew detection. The modification of the skew detection sensor using two CIS of a sheet-like body conveyance apparatus is shown, (a) is a top view after skew detection, (b) is a side view after skew detection. It is a figure explaining the detection method of the skew angle when the skew occurs between two CISs and the amount of lateral misregistration. It is a figure explaining the detection method of the skew angle and the amount of horizontal misregistration when skew arises between two CIS. It is sectional drawing which shows the modification of the position of the spindle of the roller holding member of a sheet-like body conveyance apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, about components, such as a member and a component which have the same function or shape in each drawing, after demonstrating once by attaching | subjecting the same code | symbol as much as possible, the description is abbreviate | omitted.

(Image forming device)

First, the configuration and operation of the entire image forming apparatus will be described with reference to FIGS. FIG. 1 is a block diagram showing a printer as an image forming apparatus, and FIG. 2 is an enlarged view showing an image forming unit thereof. As shown in FIG. 1, an intermediate transfer belt device 15 having an intermediate transfer belt 8 is installed at the center of the main body of the image forming apparatus 100.

Image forming units 6Y, 6M, 6C, and 6K corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged in parallel so as to face the intermediate transfer belt 8. The registration correction unit 30 serving as a lateral registration correction unit is disposed in a straight conveyance path K2 on the lower right side of the intermediate transfer belt device 15. Below the straight conveyance path K2, a paper feed unit 26 that houses a sheet-like body P as a recording medium or a transfer medium is disposed. In addition, the image forming apparatus 100 according to the present embodiment is connected to an LCT (Large-Capacity Paper Tray) as a paper feeding device so that paper can be fed from outside the main body of the image forming device 100. .

FIG. 2 is an enlarged view of the image forming unit 6Y corresponding to yellow of the image forming apparatus. The image forming unit 6Y includes a photosensitive drum 1Y, a charging unit 4Y disposed around the photosensitive drum 1Y, and a developing unit. 5Y, a cleaning unit 2Y, a charge removal unit, and the like. Then, an image forming process (charging process, exposure process, developing process, transfer process, cleaning process) is performed on the photosensitive drum 1Y, and a yellow image is formed on the photosensitive drum 1Y.

The other three image forming units 6M, 6C, and 6K have substantially the same configuration as the image forming unit 6Y corresponding to yellow except that the color of the toner used is different, and correspond to the respective toner colors. An image is formed. Hereinafter, description of the other three image forming units 6M, 6C, and 6K will be omitted as appropriate, and only the image forming unit 6Y corresponding to yellow will be described.

Referring to FIG. 2, photosensitive drum 1Y is driven to rotate counterclockwise in FIG. 2 by a drive motor. Then, the surface of the photosensitive drum 1Y is uniformly charged at the position of the charging unit 4Y (charging process). Thereafter, the surface of the photosensitive drum 1Y reaches the irradiation position of the laser beam L emitted from the exposure unit 7, and an electrostatic latent image corresponding to yellow is formed by exposure scanning at this position (exposure process). .

After the electrostatic latent image corresponding to yellow is formed, the surface of the photosensitive drum 1Y reaches a position facing the developing portion 5Y, and the electrostatic latent image is developed at this position, and a yellow toner image ( Image) is formed (development process). Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the intermediate transfer belt 8 and the transfer roller 9Y, and the toner image on the photosensitive drum 1Y is transferred onto the intermediate transfer belt 8 at this position (primary). Transfer process). At this time, a small amount of untransferred toner remains on the photosensitive drum 1Y.

The surface of the photosensitive drum 1Y reaches a position facing the cleaning unit 2Y, and untransferred toner remaining on the photosensitive drum 1Y at this position is collected in the cleaning unit 2Y by the cleaning blade 2a (cleaning step). . Finally, the surface of the photosensitive drum 1Y reaches a position facing the neutralization unit, and the residual potential on the photosensitive drum 1 is removed at this position. Thus, a series of image forming processes performed on the photosensitive drum 1Y is completed.

The image forming process described above is performed in the other image forming units 6M, 6C, and 6K similarly to the yellow image forming unit 6Y. That is, a laser beam L based on image information is irradiated from the exposure unit 7 disposed above the image forming unit onto the photosensitive drums 1M, 1C, and 1K of the image forming units 6M, 6C, and 6K. Is done.

Specifically, the exposure unit 7 emits laser light L from a light source, and irradiates the photosensitive drum through a plurality of optical elements while scanning the laser light L with a polygon mirror that is rotationally driven. Thereafter, the toner images (images) of the respective colors formed on the respective photosensitive drums through the development process are transferred onto the intermediate transfer belt 8 serving as an image carrier in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 8.

FIG. 3 shows the intermediate transfer belt device 15 of the image forming apparatus and its periphery. The intermediate transfer belt device 15 includes an intermediate transfer belt 8, four transfer rollers 9Y, 9M, 9C, and 9K, a driving roller 12A, a counter roller 12B, tension rollers 12C to 12F, an intermediate transfer cleaning unit 10, and the like. . The intermediate transfer belt 8 is stretched and supported by a plurality of roller members 12A to 12F, and is endlessly moved in the direction of the arrow in FIG. 3 by the rotational drive of one roller member (drive roller) 12A.

The four transfer rollers 9Y, 9M, 9C, and 9K respectively sandwich the intermediate transfer belt 8 with the photosensitive drums 1Y, 1M, 1C, and 1K to form a primary transfer nip. Then, a transfer voltage (transfer bias) opposite to the polarity of the toner is applied to the transfer rollers 9Y, 9M, 9C, and 9K.

The intermediate transfer belt 8 (belt-shaped image carrier) travels in the direction of the arrow and sequentially passes through the primary transfer nips of the transfer rollers 9Y, 9M, 9C, and 9K. In this way, the toner images of the respective colors on the photosensitive drums 1Y, 1M, 1C, and 1K are primarily transferred while being superimposed on the intermediate transfer belt 8.

Thereafter, the intermediate transfer belt 8 onto which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 19 (image transfer portion). At this position, the counter roller 12B sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 to form a secondary transfer nip (image transfer portion).

The four-color toner images formed on the intermediate transfer belt 8 are transferred onto a sheet-like body P such as transfer paper conveyed to the position of the secondary transfer nip (secondary transfer step). At this time, the untransferred toner that has not been transferred to the sheet-like body P remains on the intermediate transfer belt 8.

After the secondary transfer process, the intermediate transfer belt 8 reaches the position of the intermediate transfer cleaning unit 10. At this position, the untransferred toner on the intermediate transfer belt 8 is removed. Thus, a series of transfer processes performed on the intermediate transfer belt 8 is completed.

Here, referring to FIG. 1, the sheet-like body P conveyed to the position of the secondary transfer nip is disposed on the paper feeding unit 26 (or on the side) disposed below the apparatus main body 100. The sheet is fed from the sheet feeding unit 26) of the LCT 200 by the sheet feeding roller 27 and is conveyed via the sheet feeding path K1 (or the second sheet feeding path K10), the straight conveyance path K2, and the like. A plurality of sheet-like bodies P such as transfer paper are stored in the paper supply unit 26 in a stacked manner. When the paper feed roller 27 is driven to rotate counterclockwise in FIG. 1, the uppermost sheet-like body P is fed toward the paper feed path K1.

The sheet P fed to the paper feed path K1 joins the straight conveyance path K2 at the junction X on the upstream side of the registration correction section 30, and moves away from the registration correction section 30 in the straight conveyance path K2 ( It is once transported in the upper right direction in FIG. Then, after the rear end of the sheet-like body P is completely conveyed into the linear conveyance path K2, the conveyance direction of the sheet-like body P is reversed (switched back) and directed toward the registration correction unit 30 in the linear conveyance path K2. Then, the sheet-like body P is conveyed.

The sheet-like material P conveyed to the registration correction unit 30 is subjected to skew correction, lateral registration correction (width direction misalignment correction), and vertical registration correction (position misalignment correction in the conveyance direction) by the resist correction unit 30. Thereafter, the sheet-like body P is conveyed toward the secondary transfer nip (image transfer portion) in time with the color image on the intermediate transfer belt 8.

Thus, a desired color image is transferred onto the sheet-like body P. The configuration and operation of the paper feed path K1 and the straight conveyance path K2 will be described later with reference to FIG.

The sheet-like body P on which the color image is transferred at the position of the secondary transfer nip is conveyed to the position of the fixing unit 20. At this position, the color image transferred to the surface is fixed on the sheet-like body P by heat and pressure generated by the fixing belt and the pressure roller. Thereafter, the sheet-like body P is discharged to the outside of the apparatus by a discharge roller. The sheet-like bodies P discharged to the outside of the apparatus by the discharge rollers are sequentially stacked on the stack portion as an output image.

Thus, a series of image forming processes in the image forming apparatus is completed. Note that the process linear velocity (the traveling speed of the intermediate transfer belt 8 and the conveying speed of the sheet-like body P) of the image forming apparatus in the present embodiment is set to about 400 mm / second.

As described above, as shown in FIG. 1, the image forming apparatus 100 according to the present embodiment feeds the middle of the straight conveyance path K2 where the registration correction unit 30 serving as the lateral registration correction unit is installed (the merging unit X). The paper paths K1 are configured to merge. In addition, the paper feed path K1 is disposed on the inner side (left side in FIG. 1) of the linear transport path K2 on the upstream side in the transport direction (upper right side in FIG. 1). Thereby, the horizontal size of the image forming apparatus 100 can be reduced.

In this embodiment, the straight conveyance path K2 is disposed so as to be inclined such that the upstream side in the conveyance direction is higher than the downstream side in the conveyance direction. Thereby, the space between the intermediate transfer belt device 15 and the straight conveyance path K2 is used without waste, and the size of the straight conveyance path K2 in the horizontal direction can be reduced. In addition, since a large space is formed below the straight conveyance path K2, it is possible to increase the degree of freedom of the layout of the paper feeding unit 26 disposed below the straight conveyance path K2.

In the present embodiment, a curved conveyance path K4 formed in a curved shape is installed on the upstream side in the conveyance direction of the straight conveyance path K2. Furthermore, an opening 90 exposed outside the apparatus (above the apparatus) is provided on the upstream side in the conveyance direction of the linear conveyance path K2 (upstream side of the curved conveyance path K4).

With such a configuration, it is possible to transport a sheet-like body P (for example, long paper) having a large size in the transport direction without increasing the size of the image forming apparatus 100 in the horizontal direction. Specifically, when the sheet-like body P having a large size in the conveyance direction is conveyed, the sheet-like body P fed from the merging portion X is transferred to the linear conveyance path K2 and the curved conveyance path K4 on the upstream side of the merging portion X. (In some cases, a part of the sheet P is exposed from the opening 90 to the outside of the apparatus) and then transported toward the registration correction unit 30 by reversing the transport direction.

(Configuration and operation of development unit)
Next, the configuration and operation of the developing unit in the image forming unit will be described in more detail with reference to FIG. The developing unit 5Y includes a developing roller 51Y that faces the photosensitive drum 1Y, a doctor blade 52Y that faces the developing roller 51Y, two transport screws 55Y disposed in the developer containing unit, and an opening in the developer containing unit. A toner replenishment path 44Y that communicates with each other via a toner density, a density detection sensor 56Y that detects a toner density in the developer, and the like.

The developing roller 51Y includes a magnet fixed inside, a sleeve rotating around the magnet, and the like. In the developer accommodating portion, a two-component developer composed of a carrier and toner is accommodated.

The developing unit 5Y configured as described above operates as follows. The sleeve of the developing roller 51Y rotates in the direction of the arrow in FIG. The developer carried on the developing roller 51Y by the magnetic field formed by the magnet moves on the developing roller 51Y as the sleeve rotates. Here, the developer in the developing device 5Y is adjusted so that the toner ratio (toner concentration) in the developer is within a predetermined range.

Thereafter, the toner replenished in the developer accommodating portion circulates through the two separated developer accommodating portions while being mixed and stirred together with the developer by the two conveying screws 55Y (movement in the direction perpendicular to the paper surface of FIG. 2). ). The toner in the developer is attracted to the carrier by frictional charging with the carrier, and is carried on the developing roller 51Y together with the carrier by the magnetic force formed on the developing roller 51Y.

The developer carried on the developing roller 51Y is conveyed in the direction of the arrow in FIG. 2 and reaches the position of the doctor blade 52Y. The developer on the developing roller 51Y is conveyed to a position facing the photosensitive drum 1Y (development region) after the developer amount is made appropriate at this position.

Thereafter, the developer toner on the developing roller 51Y is attracted to the latent image formed on the photosensitive drum 1Y by the electric field formed in the developing region. The developer remaining on the developing roller 51Y after this adsorption reaches the upper portion of the developer accommodating portion as the sleeve rotates, and is detached from the developing roller 51Y at this position.

Next, with reference to FIGS. 3 and 4, the configuration and operation of the sheet feeding path K1, the straight conveyance path K2, and the straight conveyance path K3 will be described. In the straight conveyance path K2, a conveyance roller 28, a merging section X, and a registration correction section 30 are disposed as reversing means. The registration correction unit 30 is disposed in a horizontal straight conveyance path K3 following the straight conveyance path K2.

Then, along the conveyance direction of the linear conveyance path K3, in order from the upstream side of the linear conveyance path K3, a conveyance roller pair 31, a CIS (contact image sensor) 146 as a detection unit for detecting a lateral registration, and skew detection A first skew detection sensor 145, a second skew detection sensor 147, a sandwiching roller 33, and a secondary transfer roller 19 are disposed as detection units. A photo sensor 38 is disposed between the nipping roller (timing roller pair) 33 and the secondary transfer nip (image transfer portion). Each of the CIS 146, the first skew detection sensor 145, and the second skew detection sensor 147 may be a reflection sensor.

On the upstream side in the transport direction with respect to the secondary transfer nip, a sandwiching roller 33 is disposed as a vertical registration correction unit. The above-described linear conveyance path K2 is disposed on the upstream side in the conveyance direction reaching the pinching roller 33, and is formed so as to be inclined downward from above.

With such a configuration, a useless space between the intermediate transfer belt 8 (belt surface) and the resist correction unit 30 is reduced, and the sheet-like body P is fed into the secondary transfer nip at a steep angle. Therefore, the secondary transfer process is stably performed.

Here, the conveyance roller 28 as the reversing unit is disposed in the linear conveyance path K2 and upstream of the joining portion X in the conveyance direction of the sheet-like body P. The conveying roller 28 is configured to be able to abut and detach the rollers disposed up and down by a driving mechanism.

The transport roller 28 is configured to be rotated in the forward and reverse directions by a drive motor. Further, the junction X is switched in the transport direction of the sheet P (from the paper feed paths K1, 10 to the upstream side of the linear transport path K2, and from the upstream side of the linear transport path K2 to the downstream side). The switching claw for performing switching) is installed.

Then, the sheet-like body P conveyed from the sheet feeding path K1 to the junction X is conveyed in a direction away from the registration correction unit 30 in the linear conveyance path K2 by rotating the conveyance roller 28 in the forward direction, and then the conveyance roller The sheet 28 is rotated in the reverse direction to reverse the conveyance direction of the sheet-like body P and conveyed toward the registration correction unit 30. That is, the transport roller 28 functions as a reversing unit. In the present embodiment, the conveying roller 28 as the reversing unit is installed in the linear conveying path K2, but may be installed in the curved conveying path K4 of FIG. 1 disposed on the upstream side of the linear conveying path K2. it can.

In a state where the sheet-like body P is sandwiched between the nip portions of the sandwiching roller 33, lateral registration correction and skew of the sheet-like body P are performed by a shift and rotation operation of a roller holding member 110 shown in FIGS. 5A and 5B described later. Correction is performed.

The CIS 146 includes a plurality of photosensors (consisting of light emitting elements such as LEDs and light receiving elements such as photodiodes) arranged in the width direction, and detects the positions of both ends of the sheet-like body P in the width direction. By doing so, the amount of lateral resist misalignment is detected. Then, based on the detection result of the CIS 146, the lateral registration correction by the sandwiching roller 33 is performed.

The photo sensor 38 is disposed downstream of the sandwiching roller 33 in the transport direction of the sheet-like body P, and optically detects the leading end of the sheet-like body P transported from the sandwiching roller 33. Then, based on the detection result of the photosensor 38, the conveyance timing of the sheet-like material P conveyed toward the secondary transfer nip by the clamping roller 33 is finely adjusted.

The uppermost sheet of the sheet-like material P stored in the paper feed unit 26 is fed from the paper feed unit 26 of the image forming apparatus 100 toward the nipping roller 33 by the paper feed roller 27. The sheet-like body P is subjected to skew correction and lateral registration correction by the sandwiching roller 33, and in order to be aligned with the image formed on the photosensitive drum 5, it is timed for secondary transfer. Be transported.

The sheet P after the transfer process passes through the secondary transfer position and then reaches the fixing device 20 through the conveyance path. The sheet-like body P that has reached the fixing device 20 is fixed with an image by heating and pressing by the fixing device 20. The sheet P on which the image is fixed is delivered from the fixing device 20 and then discharged from the image forming apparatus 100. Thus, a series of image forming processes is completed.

(Sheet Conveyor)
As described above, the straight conveyance path K3 is provided along the conveyance direction of the sheet-like body P. As shown in FIG. 4, the linear conveyance path K <b> 3 is formed by linear conveyance guide plates 41 to 43 installed so as to sandwich the front and back surfaces of the sheet P to be conveyed.

The conveyance roller pair 31 and the sandwiching roller 33 have upper driven rollers 31a and 33a and lower drive rollers 31b and 33b, respectively, and sandwich the sheet-like body P at the nip portion between the two upper and lower rollers. Transport while. The driven roller 31a of the conveying roller pair 31 is arranged to be movable up and down with respect to the fixed height driving roller 31b, and is configured to be able to open and close the nip portion.

The sheet-like body conveyance device 150 of this embodiment is configured by the conveyance roller pair 31, the CIS 146, the first skew detection sensor 145, the second skew detection sensor 147, and the sandwiching roller 33. The sheet-like body conveyance device 150 performs skew correction and lateral registration correction of the sheet-like body P by the CIS 146, the first skew detection sensor 145, the second skew detection sensor 147, and the sandwiching roller 33. Hereinafter, the sheet-like body conveyance device 150 will be described with reference to FIGS. 4 to 5B.

As shown in FIG. 5A, a main body frame 151 is fixedly disposed along the conveyance path K3 below the clamping roller 33, and a base frame 152 is fixed on the main body frame 151. The base frame 152 has two upper and lower horizontal plates 153 and 154. On the upper horizontal plate 154, a roller holding member 110 that supports the sandwiching roller 33 is disposed movably in the horizontal direction.

As shown in FIG. 5B, four free bearings 111 (ball transfer) are disposed at positions corresponding to the four corners of the bottom surface of the roller holding member 110 on the upper surface of the upper horizontal plate 154. A roller holding member 110 is disposed on the free bearing 111 so as to be movable in the horizontal direction in the front-rear and left-right directions.

As is well known, the free bearing 111 is a steel ball that is rotatably fitted in the recess of the pedestal, and the top of the steel ball is in point contact with the bottom surface of the roller holding member 110. The minimum number of free bearings 111 is three, but in the illustrated example, four are provided to ensure stable movement of the roller holding member 110.

The roller holding member 110 is configured by a plate-like frame extending in a direction orthogonal to the conveying direction of the sheet-like body P. Both ends of the plate-shaped frame are bent at a right angle upward, and bearings 114 and 115 are fixed to the bent portion side by side. On one side of the lower surface of the roller holding member 110, a rotation receiver 110b extending a predetermined length in a direction orthogonal to the conveying direction of the sheet-like body P is integrally formed perpendicularly to the lower surface of the roller holding member 110.

The sandwiching roller 33 includes a lower drive roller 33b and an upper driven roller 33a. The rotating shaft of the upper driven roller 33a is supported by the upper bearing 114 of the roller holding member 110, and the rotating shaft of the lower driving roller 33b is supported by the lower bearing 115 of the roller holding member 110.

A rotary encoder 144 is mounted on the rotating shaft of the drive roller 33b that protrudes outward from the lower bearing 115. Then, based on the rotational speed of the driving roller 33b detected by the rotary encoder 144, a rotational speed variable roller driving motor 140 described later is driven, and the driven roller 33a is rotated by the rotation of the driving roller 33b. It has become.

A support shaft 110a serving as a guided portion that protrudes short downward is fixed to the lower surface on one side of the roller holding member 110. A guide roller 136 is rotatably attached to the lower end portion of the support shaft 110a, and a cam follower 135 is rotatably attached to an intermediate portion of the support shaft 110a.

On the lower horizontal plate 153, the first motor 120, the second motor 130, and the rotary encoders 128, 138 are arranged side by side in the left-right direction. One first motor 120 is used for skew compensation, and a drive pulley 121 is fixed to a rotating shaft thereof. The other second motor 130 is for lateral registration correction, and another drive pulley 131 is fixed to the rotation shaft thereof.

Instead of one rotary encoder 128, an arbitrary encoder (for example, a linear encoder) or an arbitrary sensor (for example, a laser displacement meter) for detecting the movement and position of a first rotating cam 124 and a lever member 125 described later are provided. May be. Further, in place of the other rotary encoder 138, an arbitrary encoder (for example, a linear encoder) or an arbitrary sensor (for example, a laser displacement meter) for detecting the movement and position of a second rotation cam 134 and a roller holding member 110 described later are provided. May be.

The driven pulleys 122 and 132 are rotatably supported between the upper and lower horizontal plates 153 and 154. The upper and lower ends of the rotating shafts 122a and 132a of the driven pulleys 122 and 132 are rotatably supported by the upper and lower horizontal plates 153 and 154, respectively. The rotating shafts 122a and 132a are parallel to each other. Timing belts 123 and 133 are bridged between the drive pulleys 121 and 131 and the driven pulleys 122 and 132, respectively.

Rotating plates 128a and 138a that are rotating side components of the rotary encoders 128 and 138 are fixed to the rotating shafts 122a and 132a of the driven pulleys 122 and 132 that protrude downward from the lower horizontal plate 153. A plurality of slits are continuously formed in the peripheral portions of the rotary plates 128a and 138a, and a light projecting / receiving device which is a fixed component of the rotary encoders 128 and 138 is disposed so as to sandwich the peripheral portion in the vertical direction.

A first rotating cam 124 and a second rotating cam 134 are fixed to upper ends of the rotating shafts 122a and 132a of the driven pulleys 122 and 132 protruding upward from the upper horizontal plate 154. The cam curves of the first rotating cam 124 and the second rotating cam 134 are each formed to be a constant velocity cam curve. By using the constant velocity cam, the rotation angle of the first rotation cam 124 and the second rotation cam 134 and the linear movement distance of the cam followers 126 and 135 described later are proportional to each other, and the shift position control of the support shaft 110a is performed. Further, the rotation control of the lever member 125 is facilitated.

An elongated hole 154a is formed in the upper horizontal plate 154 at a position adjacent to the one-side second rotating cam 134 as a guide portion extending in a direction orthogonal to the sheet-like body conveyance direction. A guide roller 136 at the lower end of the support shaft 110a is inserted into the elongated hole 154a. The cam follower 135 at the intermediate portion of the support shaft 110 a is in contact with the cam surface at the peripheral portion of the second rotating cam 134 by the force of the tension spring 113. The long hole 154a is for guiding the guide roller 136 to move in a straight line, and may be a long groove instead of the long hole.

A fulcrum shaft 154b projects from the horizontal plate 154 opposite to the second rotation cam 134, and a lever member 125 is disposed on the fulcrum shaft 154b so as to be rotatable in the horizontal direction. A cam follower 126 and an action roller 127 as a first pressing portion are rotatably mounted on support shafts 125a and 125b integrally formed on both ends of the lever member 125 via an arbitrary bearing material such as a ball bearing. Yes. The outer peripheral surface of the cam follower 126 is in contact with the outer peripheral surface of the first rotating cam 124 by the spring force of the first tension spring 112. The outer peripheral surface of the action roller 127 is in contact with the rotation receiver 110 b by the spring force of the first tension spring 112.

That is, the operation roller 127 as the first pressing portion is seated by the first motor 120 for skew correction, the driving pulley 121, the timing belt 123, the driven pulley 122, the first rotating cam 124, the lever member 125, and the operation roller 127. The 1st drive part which moves back and forth in the direction of the conveyance path of the shape body P is comprised.

Also, the second motor 130 for correcting lateral registration, the driving pulley 131, the timing belt 133, the driven pulley 132, and the second rotating cam 134 are in contact with the support shaft 110a as the guided portion via the cam follower 135. A second drive unit that includes two pressing portions (cam outer peripheral surfaces) and moves the support shaft 110a to the left and right in a direction orthogonal to the conveyance path of the sheet-like body P is configured.

A bracket 155 is vertically disposed on the main body frame 151 on one side of the straight conveyance path K3 and on one end side in the axial direction of the sandwiching roller 33. A rotation speed variable roller driving motor 140 for rotating the driving roller 33 b of the clamping roller 33 is fixed to the outer surface of the bracket 155. The rotation shaft of the roller drive motor 140 protrudes horizontally toward the inside of the bracket 155, and the pinion 141 is fixed to the rotation shaft protruding inward. The pinion 141 is meshed with a reduction gear 142 that is pivotally supported inside the bracket 155.

The rotation shaft 142a of the reduction gear 142 is connected to the rotation shaft 33b1 of the driving roller 33b of the pinching roller 33 via a two-stage spline coupling 143. Thereby, the rotational driving force of the roller driving motor 140 is transmitted to the driving roller 33b via the pinion 141, the reduction gear 142, and the two-stage spline coupling 143, and the pinching roller 33 is rotationally driven. Therefore, the sheet roller P can be conveyed at an arbitrary conveyance speed by the drive roller 33b being rotated by the roller drive motor 140 in a state in which the nipping roller 33 sandwiches the sheet object P.

The two-stage spline coupling 143 is a kind of constant velocity universal joint. As shown in the partial enlarged view of FIG. 5A, the first spline gear 143a, the second spline gear 143b, the intermediate spline gear 143c, the guide ring 143d, etc. It is configured.

The first spline gear 143a is an external gear, and is installed on a rotation shaft 142a that rotates together with the reduction gear 142 of the first drive unit. The rotating shaft 142a is rotatably held by the bracket 155 via a bearing.

The second spline gear 143b is also an external gear, and is connected to the rotation shaft 33b1 of the drive roller 33b of the pinching roller 33. The intermediate spline gear 143c is an internal gear, and extends in the width direction so as to always mesh with the two spline gears 143a and 143b even if the clamping roller 33 (roller holding member 110) moves in the width direction. Further, the two spline gears 143a and 143b are formed in a crown shape so as to mesh with the intermediate spline gear 143c even when the sandwiching roller 33 (roller holding member 110) rotates in an oblique direction.

By using such a two-stage spline coupling 143, the pinching roller 33 is driven to rotate favorably. That is, even if the pinching roller 33 rotates in a substantially horizontal plane around the support shaft 110a or slides in the width direction, the driving force of the roller drive motor 140 on the fixed side can drive the pinching roller 33. It is accurately and reliably transmitted to the roller 33b.

The guide ring 143d is a substantially annular stopper member installed at each of both ends in the width direction of the intermediate spline gear 143c. The two spline gears 143a and 143b move relatively in the width direction to thereby form a two-stage spline cup. It is prevented from falling off the ring 143.

The first skew detection sensor 145, the second skew detection sensor 147, and the CIS 146 are attached to the linear conveyance guide plate 41 between the conveyance roller pair 31 and the sandwiching roller 33 as shown in FIGS. Yes. The CIS 146 is a light source such as an LED, a light receiving lens, and a CMOS image sensor arranged in a single row. Detect.

The first skew detection sensor 145 and the second skew detection sensor 147 are arranged on the upstream side of the pinching roller 33 and spaced apart from each other by a predetermined distance in the conveyance direction of the linear conveyance path K3, and each is constituted by a pair of photosensors. ing. The pair of photosensors are arranged at positions that are separated from each other in the opposite direction by an equal distance from the center line L3 in the width direction of the straight conveyance path K3.

That is, the pair of photosensors are arranged symmetrically with respect to the width direction center line L3. Then, the skew angle of the sheet-like body P is detected by detecting the front end edge of the sheet-like body P in time with the pair of photosensors. The positions of the CIS 146, the first skew detection sensor 145, and the second skew detection sensor 147 can be changed between the conveyance roller pair 31 and the sandwiching roller 33.

The three motors 120, 130, 140, and the three rotary encoders 128, 138, 144 described above are connected to the control unit 160 as shown in FIG. 5A. Further, the first skew detection sensor 145, the second skew detection sensor 147, and the CIS 146 are connected to the control unit 160 via the storage accumulation unit 156.

The control unit 160 includes a tendency calculation unit 160a, and obtains a first skew angle θ1 and a second skew angle θ2, which will be described later, obtained from the storage accumulation unit 156, a first lateral registration amount δ1, a second lateral registration amount δ2, and the past 1 The (preliminary) driving amount of the nipping roller 33 for the tendency calculation unit 160a to reduce or eliminate the skew angle and the lateral misregistration amount of the sheet-like body P based on the skew angle and the lateral misregistration amount of times (previous) or plural times. Is calculated.

The storage accumulation unit 156 stores and accumulates the skew angles of at least two sheet-like bodies P detected by the first skew detection sensor 145 and the second skew detection sensor 147. In addition, the storage accumulation unit 156 stores and accumulates at least one past skew angle and lateral misregistration value of the sheet-like body P conveyed by the pinching roller 33. Although the upper limit of the number of times of storage and accumulation depends on the calculation contents of the trend calculation unit 160a and the storage amount of the memory, it is not particularly necessary to limit the upper limit of the number of times of storage and storage.

When the image forming apparatus 100 is provided with a paper feed tray that accommodates the sheet-like body P, the opening / closing of the paper feed tray may be detected by a sensor so that the data in the storage accumulation unit 156 can be reset. This is because when the paper feed tray is opened and closed, the tendency of the skew angle and the lateral registration amount up to that time may change greatly. By resetting the data in this way, the (preliminary) drive amount of the nipping roller 33 can be optimized.

The control part 160 controls the drive part (the 1st motor 120, the 2nd motor 130) of the clamping roller 33 as follows. That is, based on the first position shift amount S1 (first skew angle θ1, first lateral shift amount δ1) of the first detection detected by the first skew detection sensor 145 obtained from the storage accumulation unit 156, The drive units (first motor 120 and second motor 130) are controlled in the first stage for the first pick-up operation of the clamping roller 33. In addition, the second position shift amount S2 (second skew angle θ2, second lateral shift amount δ2) of the second detection detected by the second skew detection sensor 147 obtained from the storage accumulation unit 156 and the first position. Based on the difference position deviation amount (S2-S1) from the deviation amount S1 (first skew angle θ1, first lateral registration amount δ1), the drive unit (first motor 120, The second motor 130) is controlled in the second stage.

In addition, the trend calculation unit 160a can execute at least one of the following (1) to (4).
(1) The difference skew angle (θ2 _past −θ1 _past ) and the difference lateral misregistration amount (δ2 _past −δ1 _past ) of the sheet-like body P conveyed last time are used as the first skew angle θ1 and the first skew angle of the sheet-like body P to be conveyed this time. (2) The simple moving average value of the difference skew angle (θ2 _past −θ1 _past ) and the difference lateral registration amount (δ2 _past −δ1 _past ) of the sheet-like material P that has been conveyed a plurality of times in the _past , Add to the first skew angle θ1 and the first horizontal registration amount δ1 of the sheet-like body P to be conveyed (3) The differential skew angle (θ2 _past −θ1 _past ) and the differential lateral registration amount ( The weighted moving average value of (δ2 _past −δ1 _past ) is added to the first skew angle θ1 and the first lateral misregistration amount δ1 of the sheet-like body P to be conveyed this time. (4) The second skew angle of the sheet-like body P conveyed last time θ2 and the second lateral registration amount δ2, An arithmetic average value [(θ2 + θ1) / 2, (δ2 + δ1) / 2] of the first skew angle θ1 and the first lateral registration amount δ1 of the sheet P conveyed this time.

Based on the above calculation results (addition value, average value) of the trend calculation unit 160a, the pinching roller 33 is preliminarily driven by the drive unit (first motor 120, second motor 130). That is, the controller 160 controls the first motor 120 and the second motor 130 of the driving unit in the first stage.

As described above, the past differential skew angle (θ2 _past −θ1 _past ) and the differential lateral misregistration amount (δ2 _past −δ1 _past ) used in the first stage control are set to the past one time (previous) or a plurality of past times. be able to. When the past multiple times are used, the tendency calculation unit 160a of the control unit 160 calculates the tendency of the past multiple times of the difference skew angle (θ2 _past −θ1 _past ) and the difference lateral registration amount (δ2 _past −δ1 _past ). Can do. The tendency can be used for correcting the first skew angle θ1 and the first lateral misregistration amount δ1 in the first stage control for the sheet-like body P that is conveyed this time.

In addition to the past skew angle and lateral misregistration amount, the storage storage unit 156 adds the sheet type “type”, “size”, “direction”, “presence / absence of both sides”, environmental “temperature”, “humidity”. The image forming conditions such as “” may be stored as one set. Then, when image formation is performed again under the same image formation conditions, the tendency calculation unit 160a refers to the skew angle and the lateral misregistration amount under the same image formation conditions in the past, and preliminarily drives the sandwiching rollers 33 accordingly. You may make it do.

In addition, when performing double-sided printing, the tendency of the skew angle and the lateral misregistration amount may differ between the front and back surfaces. Therefore, when performing front surface printing, the nipping roller 33 is preliminarily driven based on data accumulated in the storage accumulation unit 156 in the past front surface printing, and when performing back surface printing, accumulation in the storage accumulation unit 156 is performed in the past back surface printing. The nipping roller 33 may be preliminarily driven based on the obtained data.

Assuming that image formation under the same image formation conditions has not been performed in the past, experiments are performed in advance under a plurality of basic image formation conditions, and basic data obtained in the experiments are stored at the time of shipment from the factory. The data may be stored and accumulated in the accumulation unit 156.

When signals from the rotary encoders 128, 138, 144 and the storage storage unit 156 are input to the control unit 160, the control unit 160 uses the three motors 120 as shown in the flowcharts of FIGS. , 130, 140 are controlled.

(Rolling member skew correction operation and lateral registration correction operation)
6A to 6D are diagrams showing the skew correction and lateral registration correction operations separately in order to easily understand the skew correction and lateral registration correction operations of the sheet-like body P described above. Actually, it is rare that only the lateral registration correction operation of FIG. 6B or the skew correction operation of FIG. 6C occurs. Usually, the skew correction operation and the lateral registration correction operation are performed as shown in FIG. It becomes a combined form.

6A to 6B show the lateral registration correction operation of the sheet-like body P. FIG. That is, when the second motor 130 is driven and the second cam 134 is rotated, the roller holding member 110 is slid to the right by the second cam 134 so as to resist the spring force of the second tension spring 113. At this time, since the cam follower 135 moves on the outer periphery of the second rotating cam 134 while rotating, the movement load of the roller holding member 110 acting on the second motor 130 for correcting lateral registration can be reduced.

Further, since the action roller 127 of the lever member 125 rolls on the surface of the rotation receiver 110b while receiving the force of the first tension spring 112, the sliding movement of the roller holding member 110 is smooth. In other words, since the action roller 127 does not receive a frictional load due to the shift movement of the roller holding member 110 in the width direction, the roller holding member 110 can be smoothly rotated and shifted. Note that when the first rotation cam 124 is stopped, the rotation receiver 110b remains stopped in the sheet conveyance direction, so that the skew correction operation of the sheet P does not occur.

FIGS. 6A to 6C show the skew correction operation of the sheet-like body P. FIG. That is, when the first motor 120 is driven and the first rotating cam 124 is rotated, the lever member 125 is pushed by the first rotating cam 124 and rotates counterclockwise about the fulcrum shaft 154b. .

As a result, the roller holding member 110 is pushed by the action roller 127 of the lever member 125 at the position of the rotation receiver 110b, so that the roller holding member 110 resists the spring force of the first tension spring 112, and the right support shaft 110a. It rotates counterclockwise around the center. At this time, the cam followers 126 and 135 move on the outer circumferences of the first rotating cam 124 and the second rotating cam 134 while rotating, so that the roller holding member 110 acting on the first motor 120 for skew correction rotates. The load is small.

6A to 6D show a combination of the lateral registration correction operation and the skew correction operation of the sheet-like body P. FIG. That is, when the first motor 120 is driven to rotate the first rotating cam 124 and the second motor 130 is driven to rotate the second cam 134, the lateral registration correction operation of (b) described above is performed. And a combination of the skew correction operations of (c) occurs.

As described above, in the present embodiment, the holding roller 33 is held by the roller holding member 110 that is movable in the width direction of the linear conveyance path K3 and is rotatable about the support shaft 110a, and the fixed side roller drive motor 140 is driven to rotate. The force is transmitted to the pinching roller 33 via the two-stage spline coupling 143. Therefore, the roller driving motor 140 and the lateral registration correcting second motor 130 can be arranged on the fixed side, and the skew correction response can be improved by reducing the weight of the structure above the roller holding member 110.

In the above-described lateral registration correction and skew correction, as shown in FIG. 7, 1) the skew angle of the sheet P is θ, 2) the lateral registration correction amount is Δy, and 3) the paper lateral registration reference (support which is the guided portion). The distance between the initial position of the shaft 110a) and the center of the support shaft 125b of the action roller 127 as the first pressing portion of the first drive unit is defined as d. Note that Δy is brass on the right side and minus on the left side from the paper lateral registration reference in FIG.

In this case, when the longitudinal movement distance of the rotation receiving portion 110b that moves back and forth by the action roller 127 is Δx, the control portion 160 performs skew as the first drive portion based on the result calculated by the following formula (1). The correction first motor 120 is controlled.
Δx = (d + Δy) tan θ (1)

The reason for multiplying (d + Δy) instead of simply multiplying tanθ in calculating Δx in the above equation (1) is as follows. That is, as described above, it is rare that only the lateral registration correction operation of FIG. 6B or the skew correction operation of FIG. 6C occurs. Usually, the skew correction operation as shown in FIG. The horizontal registration correction operation is combined.

Therefore, if the roller holding member 110 is rotated (attacking operation) by Δx calculated by the mathematical formula (2) to be described later while ignoring the Δy, the picking-up operation becomes too large or too small. That is, a skew correction error accompanying the lateral registration correction occurs.

For example, when the support shaft 110a moves to the right by Δy for lateral registration correction as shown in FIG. 7, the first motor 120 for skew correction is driven without considering this movement, and the rotation receiving portion 110b is set to Δx. If moved, the skew angle cannot be corrected. That is, since the control unit 160 calculates Δx by the following formula (2), as a result of the return operation amount being too small, the equal return operation amount at the time of return cannot correct the skew angle.
Δx = d · tan θ (2)

On the other hand, in FIG. 7, considering the case where the support shaft 110a moves to the opposite side (ie, the left side) by Δy for lateral registration correction, the first motor 120 for skew correction is driven without considering this movement. If the rotation receiving portion 110b is moved by Δx, the skew angle is corrected too much. That is, as a result of the picking operation amount being too large, the equal return operation amount at the time of reverse movement is too large and the skew angle is overcorrected.

FIG. 8A and FIG. 8B show the overcorrection of the skew angle when the support shaft 110a moves to the left by Δy for lateral registration correction in FIG. 7, and at an angle θa as shown in FIG. 8A (a). After the welcome operation, the sheet-like body P is sandwiched and returned as shown in FIG. 8B (a), so that the front edge of the sheet-like body P is skewed by (θa−θb). For the above reasons, in the embodiment of the present invention, the first motor 120 for skew correction is controlled based on the result calculated by the formula (1).

(flowchart)
Next, the operation of the above-described embodiment will be described with reference to the flowcharts of FIGS. 9A to 9C. The difference between FIG. 9A to FIG. 9C is only the first stage control of steps S4a, S4b, and S4c, and the other steps are exactly the same.
(Flowchart in FIG. 9A)
In step S1, the skew correction first motor 120, the lateral registration correction second motor 130, and the roller drive motor 140 are all turned on. In step S2, the posture (lateral registration direction, rotation direction) of the clamping roller 33 is initialized (the roller holding member 110 returns to the initial position).

When the sheet-like body P is conveyed from the right side to the left side by the conveying roller pair 31 as shown in FIGS. 10B and 10C, the first skew angle θ1 and the first lateral misregistration amount δ1 of the sheet-like body P are set in step S3. The first skew detection sensor 145 and the CIS 146 are used for detection. Then, in step S4a, the skew correction motor and the lateral registration correction motor are respectively actuated by the first skew angle θ1 and the first lateral registration amount δ1 (first stage control). As a result, the clamping roller 33 operates from the broken line to the solid line as indicated by the arrow in FIG.

In step S5, the second skew detection sensor 147 and the CIS 146 detect the second skew angle θ2 and the second lateral misregistration amount of the sheet-like body. In step S6, the difference between the difference skew angle and the difference lateral registration amount is calculated. The differential skew angle is a difference (θ2−θ1) between the first skew angle θ1 and the second skew angle θ2. The difference lateral registration amount is a difference (δ2−δ1) between the first lateral registration amount δ1 and the second lateral registration amount δ2.

Based on the differential skew angle (θ2-θ1) and the differential lateral misregistration amount (δ2-δ1) obtained in this way, the drive amount of the first motor 120 for skew correction (necessary rotation of the first rotating cam 124). Amount) is calculated, and the driving amount of the second motor 130 for lateral registration correction (required rotation amount of the second rotating cam 134) is calculated. Based on the calculation result, in step S7, the first motor 120 for skew correction and the second motor 130 for lateral registration correction are respectively subjected to differential operation (second stage control).

Next, in step S8, the sheet-like body P is clamped by the clamping roller 33 in a state where the differential operation has been completed by the first motor 120 and the second motor 130 (see FIG. 10H). In this state, while the sheet-like body P is conveyed by the sandwiching roller 33, the skew correction first motor 120 and the lateral registration correction second motor 130 are returned and operated in step S9. As a result, the sheet-like body P is corrected for skew and lateral registration, and corrected to the correct position as shown in FIG. 10J. Thereafter, by repeating the same operation as described above, the sheet-like body P in which the skew and the lateral misregistration are corrected with high accuracy is fed out from the straight conveyance path K3.

(Flowchart in FIG. 9B)
In the flowchart of FIG. 9B, in step S4b, the first skew (θ2 _past −θ1 _past ) and the differential lateral misregistration amount (δ2 _past −δ1 _past ) in the _past (previous time) The skew correction motor and the lateral registration correction motor are each greeted by an amount [(θ2 _past −θ1 _past + θ1), (δ2 _past −δ1 _past + δ1)] obtained by adding one skew angle θ1 and the first horizontal registration amount δ1. (First stage control).

That is, the first skew angle θ1 and the first skew angle θ1 and the first skew angle θ1 of the sheet-like material P to be conveyed this time are the difference skew angle (θ2 _past −θ1 _past ) and the amount of the difference lateral registration (δ2 _past −δ1 _past ). One horizontal registration amount δ1 is corrected. As a result, in the second stage control following the first stage control, the possibility of reducing the operation amount of the sandwiching roller 33 is increased compared to the control of the flowchart of FIG. The vibration suppressing effect can be enhanced.

As described above, the past differential skew angle (θ2 _past −θ1 _past ) and the differential lateral misregistration amount (δ2 _past −δ1 _past ) used in the first stage control are set to the past one time (previous) as well as the past plural It may be a batch. That is, the tendency of the difference skew angle (θ2 _past −θ1 _past ) and the difference lateral misregistration amount (δ2 _past −δ1 _past ) of the past plural times is calculated by the tendency calculation unit 160a of the control unit 160, and the sheet is conveyed this time This is used for correcting the first skew angle θ1 and the first lateral misregistration amount δ1 in the first stage control of the body P.

The cause of the skew is mainly the diameter deviation or pressure deviation of the conveying roller pair 31 on the upstream side of the sandwiching roller 33. The cause of the horizontal registration is mainly that the transport vector of the transport roller pair 31 is deviated from the vertical direction in the width direction (skew). Therefore, since the reproducibility is often included in the amount of change in the skew and the lateral registration, the “reproducibility” is calculated as a predetermined “correction amount” from the differential skew angle and the differential lateral misregistration amount for the past multiple times. The “correction amount” is reflected in the first stage control.

As a method of taking the “correction amount”, for example, the past multiple differential skew angles and differential lateral misregistration amounts are accumulated in the storage accumulation unit 156, and the average value (simple moving average value) is calculated by the trend calculation unit 160a. It can be set as the “correction amount” in the first stage control. Further, instead of the simple moving average value, a weighted moving average value that weights and averages the nearest differential skew angle and the nearest differential lateral misregistration amount may be used as the “correction amount” of the first stage control. .

In the weighted moving average value, the closer to the nearest, the larger the multiplication factor is added to the skew angle and the lateral misregistration amount. As a result, the degree of influence on the calculation result of the trend calculation unit 160a can be increased as the skew angle and the lateral misregistration amount closest to each other.

Note that when referring to the past skew angle and the amount of lateral misregistration, an extremely large value or a small value compared to a plurality of past values may be ignored as an abnormal value. For example, a value exceeding the range of the standard deviation of the past multiple skew angles and lateral misregistration amounts can be ignored as an abnormal value. In this way, by eliminating the abnormal value in the calculation of the trend calculation unit 160a, the preliminary drive amount of the pinching roller 33 can be optimized.

(Flowchart of FIG. 9C)
In the flowchart of FIG. 9C, in step S4c, the addition of the second skew angle θ2 and the second lateral misregistration amount δ2 of the past (previous) and the first skew angle θ1 and the first lateral misregistration amount δ1 transported this time. The skew correction motor and the lateral registration correction motor are actuated with average values [(θ2 + θ1) / 2, (δ2 + δ1) / 2] (first stage control).

In other words, the first skew angle θ1 and the first lateral misregistration amount δ1 of the sheet P conveyed this time are corrected with the second skew angle θ2 and the second lateral misregistration amount δ2 of the sheet P conveyed last time. As a result, in the second stage control following the first stage control, the possibility of reducing the operation amount of the sandwiching roller 33 is increased compared to the control of the flowchart of FIG. The vibration suppressing effect can be enhanced.

(Horizontal registration correction and skew compensation during conveyance of sheet-like material)
Next, with reference to FIGS. 10A to 10L, an operation for performing lateral registration correction and skew compensation while the sheet-like body P is conveyed by the conveyance roller pair 31 and the sandwiching roller 33 will be described. FIG. 10A (a) shows a state in which the sheet-like body P has advanced to the front of the first skew detection sensor 145 and the CIS 146 in a skew state.

A sheet-like body P indicated by a one-dot chain line is a normal reference position free from skew and lateral misregistration. The sheet-like body P indicated by a solid line with respect to this reference position is skewed counterclockwise by an angle β. As described later with reference to FIG. 10B, the front end edge of the sheet-like body P is detected by a pair of first skew detection sensors 145 in time, so that the time difference and the two first skew detection sensors 145 are detected. The skew state (angle β) is detected based on the relative distance. The skew angle β is calculated by the control unit 160.

In the present embodiment, the clamping roller 33 basically operates by the first stage control in the state shown in FIG. However, based on the first skew angle θ1 _past and the first lateral misregistration amount δ1 _past of the sheet-like body P when the sheet is conveyed once in the past (previous time) in FIG. The pinching roller 33 may be preliminarily driven as indicated by the alternate long and short dash line in FIG. 10A so as to reduce or eliminate the first skew angle θ1 _past and the first lateral registration amount δ1 _past . Although the posture of the sandwiching roller 33 after this preliminary driving does not necessarily correspond to the actual posture of the sheet-like body P, the preliminary driving is performed as described later, so that the sandwiching roller during the subsequent first stage control is performed. The amount of operation of 33 can be reduced, and the vibration of the pinching roller 33 when handling high-speed conveyance can be reduced.

On the other hand, FIG. 10A (b) shows a state in which the sheet-like body P has advanced to the front of the first skew detection sensor 145 and the CIS 146 while being in a lateral shift state without skew. A sheet-like body P indicated by a one-dot chain line is a normal reference position free from skew and lateral misregistration.

The sheet-like body P indicated by a solid line with respect to this reference position is laterally shifted upward (rightward in the transport direction) by the lateral registration amount α. When the right edge of the sheet-like body P is detected by the CIS 146 as shown in FIG. 10B, the lateral registration amount α is detected.

Further, the lateral registration amount in the skew state of FIG. 10A described above is calculated as the lateral registration amount α when there is no skew by combining the detection results of the first skew detection sensor 145 and the CIS 146. The lateral registration amount α is calculated by the control unit 160.

Next, when the front edge of the sheet-like body P crosses the pair of first skew detection sensors 145 as shown in FIG. 10C, the first skew angle θ1 and the first lateral misregistration amount δ1 of the sheet-like body P that are skewed and deviated. Is detected. Thereafter, the sheet-like body P is directly conveyed downstream by the conveying roller pair 31 as shown in FIG. 10D.

When the nipping roller 33 is preliminarily driven as described above based on the detection results of the first skew detection sensor 145 and the CIS 146 while the sheet-like body P is being conveyed in this way, FIG. 10A (a) From the position indicated by the alternate long and short dash line, as shown by two arrows in FIG. 10D (first stage control). The amount and timing of the pick-up operation are calculated by the control unit 160.

The amount of the pick-up operation includes the first skew angle θ1 _past and the first lateral misregistration amount δ1 _past of the previously conveyed sheet-like body P, which is the amount of preliminary driving in FIG. This is the difference between the first skew angle θ1 and the first lateral registration amount δ1. By performing preliminary driving as shown in FIG. 10A (a), the operation amount in the first stage control can be reduced, and vibration of the pinching roller 33 during high-speed conveyance can be suppressed.

FIG. 10E shows a state in which the skew angle of the sheet P increases and the sheet P changes from the broken line position to the solid line position before the front edge of the sheet P crosses the second skew detection sensor 147. Show. As described above, when the skew angle of the sheet-like body P changes after the front edge of the sheet-like body P crosses both of the first skew detection sensors 145, the first skew angle θ1 and the first lateral edge are changed as described above. The first stage control of the clamping roller 33 based on the registration amount δ1 is useless.

Therefore, in the present embodiment, as shown in FIG. 10F, before the front end edge of the sheet-like body P reaches the clamping roller 33, the second skew detection sensor 147 detects the front edge of the sheet-like body P again, Further, the side edge of the sheet-like body P is detected by the CIS 146. As a result, the second skew angle θ2 and the second lateral registration amount δ2 are detected.

Thereafter, until the front edge of the sheet-like body P reaches the pinching roller 33 as shown in FIG. 10G, the pinching roller 33 is moved from the broken line position to the solid line position by the second stage control. In the second stage control, based on the differential skew angle (θ2−θ1) between the second skew angle θ2 and the first skew angle θ1, the driving unit (first phase) is canceled so as to eliminate the differential skew angle (θ2−θ1). 1 motor 120 and 2nd motor 130) are controlled.

At the same time, based on the differential lateral registration amount (δ2−δ1) between the second lateral registration amount δ2 and the first lateral registration amount δ1, the drive unit ( The first motor 120 and the second motor 130) are controlled. Thus, preparations for correcting the sheet-like body P having the second skew angle θ2 and the second lateral registration amount δ2 by the sandwiching roller 33 are completed.

Therefore, even if the skew angle and the lateral misregistration amount of the sheet-like body P change between the first detection and the second detection, the second holding roller 33 is moved according to the change as described later. The skew and lateral registration amount of the sheet-like body P can be eliminated by tilting and lateral registration movement by the step control. In addition, since the drive for tilting and lateral registration movement of the pinching roller 33 is performed at least in the first step control and the second step control, vibration of the pinching roller 33 is suppressed even when the sheet-like body P is conveyed at high speed. Banding can be prevented.

As a result of the pick-up operation by the second stage control, the axial direction of the nip portion of the sandwiching roller 33 and the front edge of the sheet-like body P are parallel to each other, and the central portion of the nip portion in the axial direction and the width of the sheet-like body P The center of the direction matches. In this state, as shown in FIG. 10H, the front end portion of the sheet-like body P is nipped by the nip portion of the nipping roller 33.

When the front end portion of the sheet-like body P is nipped by the nip portion of the nipping roller 33, the driven roller 31a of the conveying roller pair 31 moves upwardly away as shown in FIG. Is released. Thereafter, as shown in FIG. 10J (a), the sandwiching roller 33 rotates about the support shaft 110a so as to cancel the skew angle while sandwiching and transporting the sheet-like body P, and cancels the lateral misregistration amount. To move in the width direction. As a result, the sheet-like body P is corrected to a correct position, and the sheet-like body P with the skew and the lateral misregistration corrected with high accuracy is fed out from the straight conveyance path K3.

The sheet P is simultaneously subjected to skew correction and lateral registration correction while being conveyed in this way. The timing at which the front edge of the sheet-like body P reaches the secondary transfer nip of the secondary transfer roller 19 is adjusted by the number of rotations of the pinching roller 33.

When the trailing edge of the sheet-like body P passes through the conveying roller pair 31 as shown in FIG. 10K, the nip portion of the conveying roller pair 31 is closed as shown in FIG. Prepare for transportation. When the front end edge of the sheet-like body P reaches the secondary transfer nip of the secondary transfer roller 19 as shown in FIG. 10L, the sheet-like body P is conveyed at the secondary transfer nip and is moved to a desired position on the sheet-like body P. The image is transferred to.

The clamping roller 33 is distorted in the image transferred onto the sheet P due to a difference in linear velocity between the intermediate transfer belt 8 immediately after the front edge of the sheet P reaches the image forming unit. The conveyance speed is adjusted so as not to occur.

(Image formation program)
The image forming apparatus 100 described above can perform image formation according to the flowcharts of FIGS. 9A to 9C with a dedicated apparatus configuration. 9A to 9C is generated by generating an execution program (image forming program) for causing the computer to execute the processes of the flowcharts of FIGS. 9A to 9C, and the program is installed in, for example, a general-purpose image forming apparatus. It is also possible to easily realize the image forming process including the flowchart.

The execution program installed in the computer main body can be provided by a recording medium such as a CD-ROM. In this case, the recording medium in which the execution program is recorded is set in a drive device or the like provided in the computer, and the execution program included in the recording medium is installed from the recording medium to the auxiliary storage device or the like provided in the computer via the drive device. .

As a recording medium, other than a CD-ROM, for example, a recording medium that records information optically, electrically, or magnetically, such as a flexible disk or a magneto-optical disk, a ROM (Read Only Memory), a flash memory, or the like As described above, various types of recording media such as a semiconductor memory for electrically recording information can be used.

In addition, the computer includes a network connection device that can be connected to a communication network, and obtains an execution program from another terminal connected to the communication network or executes the program to obtain the execution The result or the execution program itself in the present invention can be provided to another terminal or the like.

The auxiliary storage device provided in the computer is a storage means such as a hard disk, and can store the execution program in the present invention, a control program provided in the computer, and perform input / output as necessary. The memory device included in the computer stores an execution program read from the auxiliary storage device by the CPU. The memory device includes a ROM, a RAM (Random Access Memory), and the like.

The computer also has a CPU (Central Processing Unit), and controls the overall processing of the computer, such as various operations and input / output of data between each component, based on a control program such as an OS (Operating System) and an execution program. Thus, each processing can be realized. As a result, a special apparatus configuration is not required, and the image forming process can be efficiently realized at a low cost. Further, the image forming process can be easily realized by installing the program.

(Modification of skew detection sensor)
FIG. 11A and FIG. 11B show a modified example of the skew detection sensor, in which a second CIS 148 is arranged in parallel to the first CIS 146 on the downstream side of the first CIS 146. Two CISs 146 and 148 parallel to each other detect the amount of lateral misregistration and skew angle of the sheet-like body P. According to this modification, the cost can be reduced by reducing the number of parts by disposing two CISs having the same configuration. Note that the relative distance between the first CIS 146 and the second CIS 148 is indicated by the symbol “a” as described later in FIGS. 12A and 12B.

11A and 11B, among the pair of sensors of the first skew detection sensor 145 and the second skew detection sensor 147, each of the pair of sensors is constant in one side direction from the center line L3 in the width direction of the straight conveyance path K3. Only one sensor separated by a distance may be left and used. The one sensor 145 and the sensor 147 are used not for detecting the original skew but for detecting the leading edge of the sheet-like body P. The first CIS 146 and the second CIS 148 also have a function of detecting the leading edge of the sheet-like body P. However, when the sensor 145 and the sensor 147 are used in combination with the CIS 146 and 148, the leading edge detection accuracy is increased.

In the pick-up operation of the pinching roller 33 in the modification of FIG. 11A and FIG. 11B, the extension line of the side edge of the sheet-like body P detected by the two CISs 146 and 148 and the axial direction of the pinching roller 33 are orthogonal to each other. The skew correction first motor 120 operates. Also, from the detection results of the two CISs 146 and 148, the lateral registration amount of the sheet-like body P when the side edge of the sheet-like body P is not inclined is calculated by the control unit 160, and the lateral registration amount corresponding to the lateral registration amount is calculated. The correction second motor 130 is operated.

(Calculation method of differential lateral registration amount and differential skew angle)
Next, with reference to FIGS. 12A and 12B, a calculation method of the difference lateral registration amount and the difference skew angle that occurs between the first detection by the first CIS 146 and the second detection by the second CIS 148 will be described. . It is assumed that the sheet-like body P is conveyed from the right side to the left side at the conveyance speed v in FIG. The side edge position of the sheet product P at time _{t 1} is detected with the first CIS146 the second CIS148, shall again side end position at time _{t 2} is detected similarly.

(Calculation method of differential lateral registration amount)
FIG. 12A shows the amount of lateral registration due to the skew of the sheet-like body P. Here, “skew” means that the conveying direction of the sheet-like body P is inclined obliquely from the direction perpendicular to the axis of the conveying roller pair 31. The cause of this “skew” is considered to be that the conveyance vector of the conveyance roller pair 31 on the upstream side of the sandwiching roller 33 is shifted from the vertical direction in the width direction.

In Figure 12A, a sheet product P is in the position of Usuzumi at time _{t 1, r 1} a side edge detection position of the sheet product P at the time _{t 1} a first CIS146, sheet-like second CIS148 the side edge detection position of the body P and r _2. The relative distance between the first CIS 146 and the second CIS 148 is a. In this state, if the skew angle of the sheet-like body P is θ, the θ can be derived from the equation tan θ = (r ₂ −r ₁ ) / a.

If no skew between the first CIS146 second CIS148 (lateral registration shift amounts zero), the sheet-like member P at time _{t 2} is conveyed to the position of _{P 1} in FIG. 12A. In this case, when the side edge detection position of the sheet-like body P ₁ by the first CIS 146 is r ₁ ′ and the side edge detection position of the sheet-like body P 7 ′ of the second CIS 148 is r ₂ ′, r ₁ ′ and r ₂ 'is expressed as follows.
r ₁ ′ = r ₁ + (t ₂ −t ₁ ) v × tan θ
r ₂ ′ = r ₂ + (t ₂ −t ₁ ) v × tan θ
It becomes.

If the first CIS146 there is skew between the second CIS148, sheet product P is conveyed at time _{t 2} to the position of _{P 2} in FIG. 12A. In that case, the side edge detection position of the sheet-like body P ₂ of the first CIS 146 is r ₁ ″, and the side edge detection position of the sheet-like body P ₂ of the second CIS 148 is r ₂ ″. When the minute (difference lateral registration amount) is d, r ₁ ″ and r ₂ ″ are expressed as follows.
r ₁ ″ = r ₁ + (t ₂ −t ₁ ) v × tan θ + d
r ₂ ″ = r ₂ + (t ₂ −t ₁ ) v × tan θ + d
The differential lateral registration amount d can be obtained by solving the above two equations with θ and d as unknowns.

(Calculation method of differential skew angle)
Next, a method for calculating the differential skew angle will be described with reference to FIG. 12B. If there is no skew varies between the first CIS146 second CIS148 (differential skew angle zero), the sheet-like member P is conveyed at time _{t 2} to the position of _{P 1} in FIG. 12B. In this case, when the side edge detection position of the sheet-like body P of the _first CIS 146 is r ₁ ′ and the side edge detection position of the sheet-like body P ₁ of the second CIS 148 is r ₂ ′, r ₁ ′ and r ₂ 'Is expressed as follows.
r ₁ ′ = r ₁ + (t ₂ −t ₁ ) v × tan θ
r ₂ ′ = r ₂ + (t ₂ −t ₁ ) v × tan θ

If there is a skew varies between the first CIS146 second CIS148, sheet product P is conveyed at time _{t 2} to the position of _{P 2} in FIG. 12B. In this case, if the side end detection position of the sheet-like body P ₂ of the first CIS 146 is r ₁ ″ and the side edge detection position of the sheet-like body P ₂ of the second CIS 148 is r ₂ ″, the sheet-like body P ₂ R ₁ ″ and r ₂ ″ are expressed as follows, where θ ′ is the skew angle of
r ₁ ″ = r ₂ + {(t ₂ −t ₁ ) v + a} × tan θ ”
r ₂ ″ = r ₂ + (t ₂ −t ₁ ) v × tan θ ″
Here, the differential skew angle = θ ″ −θ, where θ ″ can be calculated from tan θ ″ = (r ₂ ″ −r ₁ ″) / a, and θ is tan θ = (r ₂ ′ −r ₂ ) / (T ₂ −t ₁ ) v, the differential skew angle (θ ″ −θ) can be obtained.

(Modification of the position of the support shaft of the roller holding member)
FIG. 13 shows a modified example of the position of the support shaft 110a of the roller holding member 110 of the sheet-like material conveyance device. That is, in the above-described embodiment, the position of the two-stage spline coupling 143 and the position of the support shaft 110a of the roller holding member 110 are set to positions separated in the axial direction of the sandwiching roller 33.

This is to make the base frame 152 as compact as possible, but there is room for improvement in order to smoothly transmit the rotational driving force from the two-stage spline coupling 143 to the driving roller 33b of the clamping roller 33. That is, in the above-described embodiment, when the roller holding member 110 is rotated about the support shaft 110a, a so-called “declination” is generated in the two-stage spline coupling 143.

Therefore, in order to avoid the occurrence of the “deflection angle”, as shown in FIG. 13, the center position (paper lateral registration reference) of the left and right movement of the support shaft 110 a of the roller holding member 110 is moved to the right side and matched with this movement position. Thus, the center of the two-stage spline coupling 143 was arranged. In this configuration, since the position of the support shaft 110a moves outward in the width direction of the linear conveyance path K3, the width of the base frame 152 is slightly larger than that in FIG. 5A, but rotational driving force is applied to the driving roller 33b of the clamping roller 33. There is an advantage that it can be accurately transmitted.

Although the embodiment of the present invention has been described above, the present invention may be detected three or more times in addition to detecting twice by the detection unit as described above. Further, the present invention can be applied to all conveying apparatuses that perform skew correction and lateral registration correction. For example, the present invention can also be applied to a conveying apparatus in which a timing roller pair is installed on the downstream side of the sandwiching roller 33 that functions as a lateral registration / skew correction roller.

The present invention can also be applied to a transfer device that transfers transfer paper and paper as the sheet-like body P, as well as a document that serves as a sheet-like body P. Further, the sheet-like material conveyance device of the present invention can be applied to other types of image forming apparatuses (for example, an ink jet type image forming apparatus or an offset printing machine).

31: Transport roller pair 33: Nipping roller 100: Image forming apparatus 110: Roller holding member 110a: Support shaft (guided portion) 110b: Rotation receiving portion 111: Free bearing 112: First tension spring 113: Second tension spring 120: skew correction motor 121: driving pulley 122: driven pulley 123: timing belt 124: first rotating cam 125: lever member 126: cam follower 127: action roller 128, 138: rotary encoder 128a, 138a: rotating plate 130: Lateral registration correction motor 131: Driving pulley 132: Driven pulley 133: Timing belt 134: Second rotating cam 135: Cam follower 136: Guide roller 140: Roller driving motor 141: Pinion 142: Reduction gear 142a: Rotating shaft 143: D Corrugated Splash Emissions Coupling 144: rotary encoder 145: first skew detection sensor 146: CIS (lateral registration detecting unit)
147: Second skew detection sensor 150: Sheet-like body conveyance device 151: Main body frame 152: Base frame 153, 154: Horizontal plate 154a: Long hole (guide portion)
154b: fulcrum axis 156: storage storage unit 160: control unit 160a: trend calculation unit

JP 2014-088263 A Japanese Patent Laid-Open No. 10-67448 Japanese Patent No. 4324047

Claims (9)

The sheet-like body is transported along a predetermined conveyance path in a state where both surfaces of the sheet-like body are sandwiched, and the sheet-like body is actuated and returned according to the positional deviation amount of the sheet-like body. In the sheet-like body conveyance device having a sandwiching roller for correcting the positional deviation amount of
A detection unit that is disposed upstream of the sandwiching roller and detects the amount of positional deviation of the sheet-like member immediately upstream of the sandwiching roller at least twice until the sheet-like member reaches the sandwiching roller. When,
A storage accumulating unit for memorizing and accumulating the amount of positional deviation detected at least twice by the detecting unit;
A drive unit for operating and returning the clamping roller;
Based on the first detection shift amount S1 of the first detection obtained from the storage accumulation unit, the drive unit is controlled in a first stage in order to perform the first pick-up operation of the clamping roller, and obtained from the storage accumulation unit. On the basis of the difference position shift amount (S2-S1) between the second position shift amount S2 of the second detection and the first position shift amount S1 of the first detection, the second roller is picked up. A control unit for controlling the driving unit in a second stage to operate;
A sheet-like body conveyance device comprising:   The said control part correct | amends the said 1st positional offset amount S1 used by the said 1st step control based on the said 2nd positional offset amount S2 of the sheet-like body conveyed in the past. Sheet-like body conveyance device.   The control unit corrects the first positional deviation amount S1 used in the first stage control based on the differential positional deviation amount (S2-S1) of the sheet-like material conveyed in the past. The sheet-like body conveyance device according to claim 1. The sheet-shaped body is transported along a predetermined transport path in a state where both sides of the sheet-shaped body are sandwiched, and the pick-up operation and the return operation are performed in accordance with the skew angle of the sheet-shaped body. In the sheet-like body conveyance device having a sandwiching roller for correcting the skew angle,
A detector disposed upstream of the pinching roller and detecting a skew angle of the sheet-like body immediately upstream of the pinching roller at least twice before the sheet-like body reaches the pinching roller; ,
A storage unit for storing and storing a skew angle detected at least twice by the detection unit;
A drive unit that tilts the picking roller for picking up and returning; and
Based on the first skew angle θ1 of the first detection obtained from the storage accumulation unit, the driving unit is controlled in a first stage to perform the first pick-up operation of the clamping roller, and is obtained from the storage accumulation unit. Based on the differential skew angle (θ2−θ1) between the second skew angle θ2 of the second detection and the first skew angle θ1 of the first detection, A control unit for controlling the driving unit in a second stage;
A sheet-like body conveyance device comprising: The sheet-like body is transported along a predetermined conveyance path in a state where both surfaces of the sheet-like body are sandwiched, and the sheet-like body is actuated and returned according to the lateral registration amount of the sheet-like body. In the sheet-like body conveyance device having a sandwiching roller for correcting the lateral registration amount of
A detection unit that is disposed on the upstream side of the sandwiching roller and detects a lateral misregistration amount of the sheet-like body immediately upstream of the sandwiching roller at least twice until the sheet-like body reaches the sandwiching roller. When,
A storage accumulating unit for memorizing and accumulating the lateral misregistration amount detected at least twice by the detecting unit;
A drive unit that shifts and moves the clamping roller for the operation and the return operation;
Based on the first lateral registration amount δ1 of the first detection obtained from the storage accumulation unit, the drive unit is controlled in a first stage to obtain the first pick-up operation of the clamping roller, and obtained from the storage accumulation unit. On the basis of the difference lateral registration amount (δ2−δ1) between the obtained second lateral registration amount δ2 of the second detection and the first lateral registration amount δ1 of the first detection, the second roller is picked up. A control unit for controlling the driving unit in a second stage to operate;
A sheet-like body conveyance device comprising: The sheet-like body is conveyed along a predetermined conveyance path in a state where both surfaces of the sheet-like body are sandwiched, and the pickup operation and the return operation are performed in accordance with the skew angle and the lateral misregistration amount of the sheet-like body. In a sheet-like material transport apparatus having a sandwiching roller that corrects the skew angle and lateral misregistration amount of the sheet-like material,
A skew angle and a lateral misregistration amount of the sheet-like body that is disposed on the upstream side of the sandwiching roller and is immediately upstream of the sandwiching roller are detected at least twice before the sheet-like body reaches the sandwiching roller. A detector to perform,
A storage unit for storing and storing a skew angle and a lateral registration amount detected at least twice by the detection unit;
A drive unit that tilts and shifts to move and return the clamping roller; and
Based on the first skew angle θ1 and the first lateral misregistration amount δ1 of the first detection obtained from the storage accumulation unit, the driving unit is controlled in a first stage to perform the first pick-up operation of the clamping roller, The difference between the second skew angle θ2 and the second lateral misregistration amount δ2 of the second detection obtained from the storage accumulation unit, and the first skew angle θ1 and the first lateral misregistration amount δ1 of the first detection. A control unit for controlling the driving unit in a second stage to perform the second pick-up operation of the nipping roller based on a skew angle (θ2-θ1) and a differential lateral registration amount (δ2-δ1);
A sheet-like body conveyance device comprising:   The control unit calculates a moving average value from the second skew angle θ2 and the second lateral misregistration amount δ2 of the sheet-like material conveyed in the past accumulated in the storage accumulation unit, and based on the moving average value, 7. The sheet-like body conveyance device according to claim 6, wherein the driving unit is controlled in a first stage.   An image forming apparatus comprising: a sheet feeding tray that accommodates the sheet-like body; and the sheet-like body conveyance device according to claim 1. 9. The image forming apparatus according to claim 8, wherein when the sheet feeding tray is opened and closed, a skew angle and a lateral misregistration amount of a past sheet-like body accumulated in the storage accumulation unit are reset.

Images