JP2020147426A - Transport device and image formation device - Google Patents

Abstract

To prevent displacement of a sheet in a width direction caused by inclination of correction means.SOLUTION: A transport device has correction means 31 which corrects a sheet position in a rotation direction and a seat width direction within a sheet transport surface. After the correction means 31 performs position correction of a sheet P, the transport device detects an inclination θ of the correction means 31 in the rotation direction within the sheet transport surface and controls components so that the correction means 31 moves in the sheet width direction based on the detected inclination θ of the correction means 31.SELECTED DRAWING: Figure 17

Description

The present invention relates to a transport device for transporting a sheet and an image forming apparatus including the transport device.

As a transport device for transporting sheets, for example, there is a transport device for transporting sheets such as paper and originals in an image forming apparatus such as a copier or a printer.

In this type of transport device, in order to correct the skew of the sheet, the transported sheet is abutted against the nip of the stopped transport roller pair to correct the skew of the sheet, and then the sheet is conveyed at a predetermined timing. A method of transporting the sheet to the target position by starting the rotation of the roller pair is adopted. However, this method has a problem that the productivity (image formation speed) is lowered because the sheet is temporarily stopped.

In response to such a problem, in Patent Document 1 (Japanese Unexamined Patent Publication No. 2018-16492), in order to enable accurate transfer of a sheet without lowering productivity, correction is performed while the sheet is conveyed by a pair of correction rollers. A transport device has been proposed that corrects the misalignment of the seat by moving the rollers in the direction opposite to the misalignment of the seat.

By the way, in the conventional transport device, the position shift in the width direction of the sheet may occur due to the inclination of the correction means.

In order to solve the above problems, the present invention has a position detecting means for detecting the position of the sheet, and while transporting the sheet, in the sheet conveying surface according to the position of the sheet detected by the position detecting means. The correction means for correcting the position of the sheet in the rotation direction and the sheet width direction, and after the correction means corrects the position of the sheet, the inclination of the correction means in the rotation direction in the sheet transport surface is detected. It is characterized in that it includes a detecting means for controlling the correction means and a control means for controlling the correction means so as to move in the seat width direction based on the detected inclination of the correction means.

According to the present invention, it is possible to prevent the position shift of the sheet in the width direction due to the inclination of the correction means.

It is a schematic block diagram of the inkjet type image forming apparatus which concerns on one Embodiment of this invention. It is a top view of the transport device which concerns on this embodiment. It is a side view of the drive mechanism which drives a correction roller. It is a top view of the drive mechanism which drives a correction roller. (A) is a diagram showing a state in which the holding frame is moved only in the width direction, (b) is a diagram showing a state in which the holding frame is moved only in the rotation direction in the paper transport surface, and (c) is a diagram showing a state in which the holding frame is moved only in the width direction. It is a figure which shows the state which moved in both directions of the rotation direction in a paper transport surface. It is a block diagram which shows the control system of the transport device which concerns on this embodiment. It is a figure for demonstrating the calculation method of the paper misalignment amount. It is a figure for demonstrating the calculation method of the paper misalignment amount. It is a figure which shows the movement of the transport device which concerns on this embodiment, (a) is a plan view, (b) is a side view. It is a figure which shows the movement of the transport device which concerns on this embodiment, (a) is a plan view, (b) is a side view. It is a figure which shows the movement of the transport device which concerns on this embodiment, (a) is a plan view, (b) is a side view. It is a figure which shows the movement of the transport device which concerns on this embodiment, (a) is a plan view, (b) is a side view. It is a figure which shows the movement of the transport device which concerns on this embodiment, (a) is a plan view, (b) is a side view. It is a figure which shows the movement of the transport device which concerns on this embodiment, (a) is a plan view, (b) is a side view. It is a figure which shows the flowchart of the transport operation. It is a top view which shows the state which the correction roller is arranged in the direction of a home position. It is a top view which shows the state which the correction roller is inclined with respect to the direction of a home position. It is a top view which shows the state which moved the correction roller in one direction in the width direction based on the calculated displacement amount. It is a top view which shows the state which moved the correction roller to the other side in the width direction based on the calculated misalignment amount. It is a figure which shows the example which applied the transfer apparatus which concerns on this invention to an electrophotographic image forming apparatus. It is a figure which shows the example which applied the transfer apparatus which concerns on this invention to a post-processing apparatus.

Hereinafter, the present invention will be described with reference to the accompanying drawings. In each drawing for explaining the present invention, components such as members and components having the same function or shape will be described once by giving the same reference numerals as much as possible. Omit.

FIG. 1 is a schematic configuration diagram of an inkjet image forming apparatus according to an embodiment of the present invention.

[overall structure]
The inkjet image forming apparatus 100 according to the present embodiment is mainly composed of a paper feeding unit 1, an image forming unit 2, a drying unit 3, and a paper ejection unit 4. In the inkjet image forming apparatus 100, an image is formed on the paper P as a sheet supplied from the feeding unit 1 by the image forming unit 2 with ink which is a liquid for image forming. Then, after the ink adhering to the paper P is dried in the drying unit 3, the paper P is discharged from the paper ejection unit 4. Further, in the case of double-sided printing, after the image is formed on the front side surface of the paper P in the image forming unit 2, the drying process is performed in the drying unit 3, and the paper P is conveyed to the reverse transfer path 150 without being discharged. To do. The paper P is supplied to the image forming unit 2 again in a state of being inverted upside down by passing through the inverted transport path 150, and after the image is formed on the back surface of the paper P in the image forming unit 2, the drying unit The drying process is performed in No. 3, and the paper is discharged from the paper ejection unit 4.

[Paper feed section]
The paper feed unit 1 is mainly fed from a paper feed tray 5 on which a plurality of paper Ps are loaded, a feeding device 6 that separates and feeds one sheet of paper P from the paper feed tray 5, and a feeding device 6. It is composed of a transport device 7 for transporting the separated paper P. As the feeding device 6, any feeding device such as a device using rollers and rollers and a device using air suction can be used. The paper P sent out from the paper feed tray 5 by the feeding device 6 is conveyed to the image forming unit 2 by the conveying device 7.

[Image forming part]
The image forming unit 2 mainly receives the fed paper P and delivers the paper P as a first transport rotating body to the paper carrying drum 9 on the outer peripheral surface of the paper P as a first transport rotating body. It was conveyed by a paper-supporting drum 9 as a second transport rotating body that is supported and conveyed, an ink ejection unit 10 that ejects ink toward the paper P supported on the paper-supporting drum 9, and a paper-supporting drum 9. It is composed of a transfer cylinder 11 as a third transfer rotating body that transfers the paper P to the drying unit 3. The transfer cylinder 8 on the upstream side, the paper carrier drum 9, and the transfer cylinder 11 on the downstream side also serve as a part of the transfer device 7 for transporting the paper P.

The tip of the paper P conveyed from the paper feed unit 1 to the image forming unit 2 is gripped by a swingable gripper 16 as a receiving unit provided on the surface of the transfer cylinder 8, and the surface of the transfer cylinder 8 is moved. It is transported along with it. The paper P conveyed by the delivery cylinder 8 is delivered to the paper-carrying drum 9 at a position facing the paper-carrying drum 9. In the example shown in FIG. 1, only one gripper 16 is described, but a plurality of grippers 16 may be provided on the transfer cylinder 8.

A similar gripper is provided on the surface of the paper-carrying drum 9 as a receiving portion, and the tip of the paper is gripped by the gripper. Further, a plurality of suction holes are dispersedly formed on the surface of the paper-supporting drum 9, and a suction device 12 generates a suction airflow toward the inside of the paper-supporting drum 9 in each suction hole. The tip of the paper P delivered from the delivery cylinder 8 to the paper-carrying drum 9 is gripped by the gripper, and is adsorbed on the surface of the paper-carrying drum 9 by the suction airflow. Be transported.

The ink ejection unit 10 according to the present embodiment ejects four colors of ink, C (cyan), M (magenta), Y (yellow), and K (black), to form an image, and forms an image for each ink. It includes individual liquid discharge heads 10C, 10M, 10Y, and 10K. The liquid discharge heads 10C, 10M, 10Y, and 10K are not limited in their configuration as long as they discharge liquid, and any configuration can be adopted. If necessary, a liquid ejection head that ejects a special ink such as white, gold, or silver may be provided, or a liquid ejection head that ejects a liquid that does not form an image, such as a surface coating liquid, may be provided.

The discharge operation of the liquid discharge heads 10C, 10M, 10Y, and 10K of the ink discharge unit 10 is controlled by a drive signal corresponding to the image information. When the paper P supported on the paper-carrying drum 9 passes through the region facing the ink ejection unit 10, each color ink is ejected from the liquid ejection heads 10C, 10M, 10Y, and 10K, and an image corresponding to the image information is displayed. It is formed. In the present embodiment, the image forming unit 2 is not limited in its configuration as long as the liquid is adhered to the paper P to form an image.

[Dry part]
The drying unit 3 is mainly composed of a drying mechanism 13 for drying the ink adhering on the paper P in the image forming unit 2 and a conveying mechanism 14 for conveying the paper P conveyed from the image forming unit 2. Has been done. The paper P conveyed from the image forming unit 2 is received by the conveying mechanism 14, is conveyed so as to pass through the drying mechanism 13, and is delivered to the paper ejection unit 4. When passing through the drying mechanism 13, the ink on the paper P is subjected to a drying treatment, whereby liquids such as water in the ink evaporate, and the ink adheres to the paper P and curls the paper P. Is suppressed.

[Paper ejection section]
The paper ejection unit 4 is mainly composed of a paper ejection tray 15 on which a plurality of sheets P are loaded. The paper P conveyed from the drying unit 3 is sequentially stacked and held on the output tray 15. In this embodiment, the paper ejection unit 4 is not limited in its configuration as long as it ejects the paper P.

[Other additional functions]
The inkjet image forming apparatus 100 according to the present embodiment is composed of a paper feeding unit 1, an image forming unit 2, a drying unit 3, and a paper ejection unit 4, but other functional units may be added as appropriate. For example, after adding a pre-processing unit that performs pre-processing of image formation between the paper feeding unit 1 and the image forming unit 2, or after performing post-processing of image formation between the drying unit 3 and the paper discharging unit 4. A processing unit can be added.

Examples of the pretreatment unit include a treatment liquid coating process for applying a treatment liquid to the paper P to react with the ink to suppress bleeding, but the content of the pretreatment is not particularly limited. .. Further, as the post-processing unit, for example, a paper reversal transfer process for inverting the paper P on which the image is formed by the image forming unit 2 and sending it to the image forming unit 2 again to form an image on both sides of the paper P is performed. , A process of binding a plurality of sheets of paper P on which an image is formed can be mentioned, but the content of the post-processing is not particularly limited.

The "image" formed on the paper is not limited to the one in which a significant image such as characters and figures is visualized, and includes, for example, a pattern having no meaning in itself. In addition, the material of the "sheet" on which the image is formed is not limited, and liquids such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, and ceramics can adhere even temporarily. Anything may be used, for example, it may be used for film products, cloth products for clothing, building materials such as wallpaper and floor materials, and leather products. The "liquid" may have a viscosity and surface tension that can be discharged from the head, and is not particularly limited, but has a viscosity of 30 mPa · s or less at room temperature, under normal pressure, or by heating or cooling. It is preferable to have. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functionalizing materials such as surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium. , Solvents, suspensions, emulsions and the like containing edible materials such as natural pigments, and the like, and these can be used in applications such as inks for inkjets and surface treatment liquids.

Further, the "injection type image forming apparatus" includes an apparatus in which the liquid discharge head and the sheet material move relative to each other, but the present invention is not limited to this. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

The "liquid discharge head" is a functional component that discharges and ejects liquid from a discharge hole (nozzle). As an energy generation source for discharging liquid, a piezoelectric actuator (laminated piezoelectric element and thin-film piezoelectric element), a thermal actuator using an electrothermal conversion element such as a heat generating resistor, and an electrostatic actuator composed of a vibrating plate and a counter electrode are discharged. Although energy generating means can be used, the discharge energy generating means to be used is not limited.

Subsequently, the transport device 7 included in the paper feed unit 1 according to the present embodiment will be described.

FIG. 2 is a plan view of the transport device according to the present embodiment.

As shown in FIG. 2, the transport device 7 changes the positions of the three CIS 101 to 103 as position detecting means for detecting the position of the paper P to be transported, and the paper P while transporting the paper P, and the positions thereof. A pair of correction rollers 31 as correction means for correcting the above speed and a pair of upstream side rollers 44 as upstream side transport means arranged on the upstream side in the transport direction with respect to the correction roller 31 are provided. In the following description, the plurality of CIS 101 to 103 are the first CIS (first position detecting means) 101, the second CIS (second position detecting means) 102, and the third CIS, in order from the upstream side in the paper transport direction. It will be referred to as CIS (third position detecting means) 103.

In recent years, CIS has used a small LED (Light Emitting Diode) as a light source for the purpose of downsizing the device, and has used a contact image sensor (Contact Image) that directly reads an image with a linear sensor via a lens. It is called a Sensor). Each CIS 101 to 103 can detect the side end Pa on one end side in the width direction of the paper P by a plurality of line sensors provided in the width direction of the paper P. In the present specification, the "paper width direction" or the "width direction" means a direction orthogonal to or intersecting with the ideal paper transport direction X (see FIG. 16) on the paper transport surface. .. The first CIS 101 is arranged on the upstream side in the transport direction with respect to the upstream roller 44, and the second CIS 102 is arranged between the correction roller 31 and the upstream roller 44. The third CIS 103 is arranged between the correction roller 31 and the transfer cylinder 8 as the downstream transfer means arranged on the downstream side in the transport direction. Further, the CIS 101 to 103 are arranged parallel to the width direction of the paper P.

The pair of correction rollers 31 move in the width direction (arrow S direction in FIG. 2) of the paper P while sandwiching the paper P being conveyed, or move in the paper transport surface centering on the support shaft 73 (FIG. 2). Change the position of the paper P by rotating it (in the direction of the arrow W in the middle). As a result, the misalignment α in the width direction of the paper P and the misalignment β in the skew are corrected. In the present embodiment, the support shaft 73 is provided on the one end side in the axial direction of the correction roller 31, but the support shaft 73 may be provided at the center position in the axial direction of the correction roller 31.

3 and 4 show the configuration of the drive mechanism that drives the correction roller. FIG. 3 is a side view of the drive mechanism, and FIG. 4 is a plan view of the drive mechanism.

As shown in FIG. 3, the correction roller 31 is composed of a drive roller 31a that is rotationally driven around the roller axis and a driven roller 31b that is driven and rotated together with the drive roller 31a. These correction rollers 31 are rotatably held around the roller axis by a holding frame 72 as a holding member. The holding frame 72 is supported by a base frame 71 fixed to the main body frame 70 of the image forming apparatus.

As shown in FIG. 4, the holding frame 72 is provided on the base frame 71 via a free bearing (ball transfer) 95 as a relay support member. As a result, the holding frame 72 is configured to be movable with respect to the base frame 71 in any direction in the paper transport surface (inside the sheet transport surface) along the upper surface thereof. By supporting the holding frame 72 using the free bearing 95 in this way, the frictional load when the holding frame 72 moves can be extremely reduced. Therefore, the misalignment correction of the paper, which will be described later, can be performed at high speed and with high accuracy. In the present embodiment, the holding frame 72 is supported by four free bearings 95, but the number of free bearings 95 may be three or more.

Further, as shown in FIG. 3, the holding frame 72 is provided with the support shaft 73, which is the center of rotation of the correction roller 31 in the paper transport surface, so as to extend downward. The lower end of the support shaft 73 is inserted into the width direction guide portion 71a formed on the base frame 71. The width direction guide portion 71a is a hole portion formed so as to extend substantially linearly in the width direction (direction of arrow S in FIG. 4). A guide roller 79 is rotatably provided at the lower end of the support shaft 73, and the support shaft 73 is inserted so as to come into contact with the width direction guide portion 71a via the guide roller 79. When the support shaft 73 moves in the width direction along the width direction guide portion 71a, the holding frame 72 and the correction roller 31 held by the holding frame 72 also move in the width direction. Further, the holding frame 72 is also configured to rotate around the support shaft 73 in the paper transport surface (in the direction of arrow W in FIG. 4). As the holding frame 72 rotates about the support shaft 73, the correction roller 31 rotates in the paper transport surface.

As shown in FIG. 3, the bracket 69 provided on the right end side of the main body frame 70 has a transport drive motor (convey drive means) 61 that applies a driving force for transporting paper to the correction roller 31. It is provided. The transport drive motor 61 and the drive roller 31a of the correction roller 31 are connected to each other via a gear train composed of a plurality of gears 66 and 67 and a coupling mechanism 65. The coupling mechanism 65 maintains the connection so that the driving force can be transmitted even if the rotating shaft of the driving roller 31a and the rotating shaft of the gear 67 are axially separated or approached from each other or driven in a direction in which they are inclined to each other. It is a two-stage spline coupling. By connecting the drive roller 31a and the gear 67 via the coupling mechanism 65 in this way, the correction roller 31 moves in the width direction or rotates in the paper transport surface to and the drive roller 31a. Even if the relative position with the transfer drive motor 61 changes, the driving force can be satisfactorily transmitted from the transfer drive motor 61 to the drive roller 31a.

Further, as shown in FIG. 3, the transport speed of the drive roller 31a (rotational speed of the transport drive motor 61) is detected at the end of the drive roller 31a (the end opposite to the transport drive motor 61 side). A rotary encoder 96 is provided as a transport speed detecting means. The speed of the correction roller 31 is controlled based on the detection result of the rotary encoder 96.

Further, the transport device 7 according to the present embodiment has a width direction drive mechanism 38 for moving the holding frame 72 and the correction roller 31 in the width direction of the paper, and the holding frame 72 and the correction roller 31 in the rotation direction in the paper transport surface. It is provided with a oblique direction drive mechanism 39 for rotating.

As shown in FIGS. 3 and 4, the width direction drive mechanism 38 includes a width direction drive motor (width direction drive means) 62, a timing belt 97, a cam 45, a tension spring 59, and the like. The tension spring 59 is connected to the holding frame 72 and the base frame 71 so as to urge the holding frame 72 in one direction in the width direction (left direction in FIG. 4). The cam 45 is provided on the base frame 71 so as to be rotatable around the rotation shaft 45a. Further, the cam 45 is held in contact with the cam follower 46 provided on the support shaft 73 by the urging force of the tension spring 59. When the cam 45 rotates, the cam follower 46 is pushed against the urging force of the tension spring 59, so that the holding frame 72 moves in the width direction (right direction in FIG. 4).

Further, as shown in FIG. 3, a timing belt 97 is hung between the rotating shaft 45a of the cam 45 and the motor shaft of the width direction drive motor 62. As a result, the driving force is transmitted from the width direction driving motor 62 to the cam 45 via the timing belt 97. Further, the rotation shaft 45a of the cam 45 is provided with a rotary encoder 57 as a rotation angle detecting means for detecting the rotation angle (rotation amount) of the cam 45. By controlling the drive of the width direction drive motor 62 based on the detection result of the rotary encoder 57, the rotation angle of the cam 45 is controlled, and the amount of movement of the holding frame 72 in the width direction is adjusted. That is, the rotary encoder 57 functions as a width direction movement amount detecting means for detecting the movement amount when the holding frame 72 and the correction roller 31 move in the width direction.

As shown in FIGS. 3 and 4, the oblique direction drive mechanism 39 includes an oblique direction drive motor (oblique direction drive means) 63, a timing belt 98, a cam 47, a tension spring 60, a lever member 50, and the like. ing. The tension spring 60 is connected to the holding frame 72 and the base frame 71 so as to urge the holding frame 72 in one direction in the oblique direction (clockwise about the support shaft 73 in FIG. 4). The cam 47 is provided on the base frame 71 so as to be rotatable around the rotation shaft 47a. Further, the cam 47 is held in contact with the cam follower 48 provided at one end of the lever member 50 by the urging force of the tension spring 60. Further, an action roller 49 is rotatably provided at the end on the opposite side of the lever member 50. The action roller 49 is held in contact with the protrusion 72a provided on the holding frame 72 by the urging force of the tension spring 60. With this configuration, when the cam 47 rotates and the cam follower 48 is pushed by the cam 47, the lever member 50 rotates about the rotation shaft 50a. Along with this, the action roller 49 provided on the lever member 50 pushes the protrusion 72a of the holding frame 72 against the urging force of the tension spring 60, so that the holding frame 72 rotates in the direction of rotation in the paper transport surface. Rotate (counterclockwise in FIG. 4).

Further, as shown in FIG. 3, a timing belt 98 is hung between the rotating shaft 47a of the cam 47 and the motor shaft of the oblique direction drive motor 63. As a result, the driving force is transmitted from the oblique direction drive motor 63 to the cam 47 via the timing belt 98. Further, the rotation shaft 47a of the cam 47 is provided with a rotary encoder 58 as a rotation angle detecting means for detecting the rotation angle (rotation amount) of the cam 47. By controlling the drive of the oblique direction drive motor 63 based on the detection result of the rotary encoder 58, the rotation angle of the cam 47 is controlled, and the amount of rotation of the holding frame 72 in the paper transport surface is adjusted. That is, the rotary encoder 58 functions as an oblique direction movement amount detecting means for detecting the amount of movement in the oblique direction when the holding frame 72 and the correction roller 31 rotate in the paper transport surface.

FIG. 5 (a) shows a state in which only the cam 45 of the width direction drive mechanism 38 rotates and the holding frame 72 moves in the width direction, and FIG. 5 (b) shows the oblique direction drive mechanism. Only the cam 47 of 39 is rotated, and the holding frame 72 is rotated in the paper transport surface. Further, FIG. 5C shows a state in which both cams 45 and 47 are rotated, the holding frame 72 is moved in the width direction, and the holding frame 72 is rotated in the paper transport surface.

FIG. 6 is a block diagram showing a control system of the transport device according to the present embodiment.

The transport device according to the present embodiment includes a control unit 20 as a control means for controlling the correction roller 31 in order to correct the misalignment of the paper. As shown in FIG. 6, the control unit 20 has a misalignment amount calculation unit 21 that calculates the misalignment amount of the paper from the detection results of CIS 101 to 103, and a misalignment in the width direction of the paper caused by the transportation of the correction roller 31. It is provided with a width direction deviation amount calculation unit 22 for calculating the amount. The control unit 20 sets the width direction drive motor 62 and skew based on the paper misalignment amount calculated by the misalignment amount calculation unit 21 and the width misalignment amount calculated by the width direction misalignment calculation unit 22. The drive of the directional drive motor 63 is controlled, and the correction roller 31 is driven in the width direction and the rotation direction in the paper transport surface.

Subsequently, a method of calculating the amount of paper misalignment based on the detection results of CIS 101 to 103 will be described with reference to FIGS. 7 and 8.

As shown in FIG. 7, when the tip portion Pb of the paper P passes through the first CIS 101 and reaches the second CIS 102, the misalignment amount α in the width direction of the paper P and the skew misalignment amount β Detected.

Specifically, the misalignment amount α in the width direction is calculated based on the position in the width direction of the paper P (the position of the side end portion Pa of the paper P) detected by the second CIS 102. That is, the position in the width direction detected by the second CIS 102 is compared with the transport reference position K, and the distance K1 in the width direction between them is the amount of misalignment α in the width direction of the paper P.

Further, the skew misalignment β is calculated from the difference in the position of the paper P in the width direction detected by each of the first CIS 101 and the second CIS 102. That is, as shown in FIG. 7, when the tip portion Pb of the paper P reaches the second CIS 102, the distances K1 and K2 in the width direction from the transport reference position K by the first CIS 101 and the second CIS 102. Is detected. Then, from these distances K1 and K2 and the preset distance M1 between the first CIS101 and the second CIS102, oblique movement is performed using the equation tanβ = (K1-K2) / M1. The amount of misalignment β of is calculated.

In this way, the amount of misalignment α in the width direction and the amount of misalignment β in the skew are calculated. As shown in FIG. 8, when the sheet moves from the position of P to the position of P'by performing the misalignment correction of skewing, the amount of misalignment in the width direction changes from α to α'. Therefore, by calculating the amount of misalignment α'in the width direction in advance, it is possible to perform more accurate misalignment correction. However, the amount of misalignment α'in the width direction changes depending on which position is used as the reference for the misalignment correction of skew.

The method for calculating the amount of paper misalignment has been described above by taking the first CIS101 and the second CIS102 as examples. However, when the second CIS102 and the third CIS103 are used, the amount of paper misalignment is calculated in the same manner. Can be detected.

Hereinafter, the operation of the transport device according to the present embodiment will be described with reference to the flowcharts of FIGS. 9 to 14 and 15.

As shown in FIGS. 9A and 9B, when the paper P is conveyed, the correction roller 31 is arranged at a home position whose roller axis is orthogonal to the conveying direction (left-right direction in the drawing). There is. Further, in this state, the pair of correction rollers 31 are separated from each other and stand by in a stationary state.

After that, as shown in FIGS. 10A and 10B, when the tip Pb of the paper P passes through the first CIS101 and reaches the second CIS102, the paper is formed by the first CIS101 and the second CIS102. "First position detection" for detecting the position of the side end Pa of P is performed (S1 in FIG. 15). Then, based on the position information detected by these CIS 101 and 102, the position shift amount α in the width direction (or the position shift amount α'including the shift amount due to the skew position shift correction) and the skew position. The deviation amount β is calculated by the position deviation amount calculation unit 21 (see FIG. 6). Then, the width direction drive motor 62 and the oblique direction drive motor 63 are controlled based on the calculated misalignment amount, and the correction roller 31 is moved in the width direction (in the direction of the arrow S1 in FIG. 10) and the paper. Rotate in the direction of rotation in the transport surface (in the direction of arrow W1 in FIG. 10). As a result, a "pick-up operation" is performed in which the correction roller 31 faces the tip end portion Pb of the paper P (S2 in FIG. 15).

After that, when the correction rollers 31 come into contact with each other at a predetermined timing and the rotation is started, as shown in FIGS. 11 (a) and 11 (b), the paper P is welcomed by the correction rollers 31 facing each other, and the correction rollers 31 The paper P is conveyed while being sandwiched. On the other hand, the upstream rollers 44 are separated from each other.

After that, as shown in FIGS. 12A and 12B, the correction roller 31 is driven in the direction opposite to the picking operation (arrow S2 direction and arrow W2 direction in the figure) while the paper P is conveyed by the correction roller 31. The "return operation" is performed (S3 in FIG. 15). As a result, "first correction" is performed in which the misalignment of the paper P in the width direction and the misalignment of the skew are corrected.

Further, as shown in FIGS. 13 (a) and 13 (b), when the tip Pb of the paper P reaches the third CIS 103, the second CIS 102 and the third CIS 103 again cause the side end Pa of the paper P. "Second position detection" for detecting the position is performed (S4 in FIG. 15). Then, based on the position information detected by these CIS 102 and 103, the position shift amount in the width direction and the position shift amount in the oblique direction are calculated by the position shift amount calculation unit 21. Then, the width direction drive motor 62 and the oblique direction drive motor 63 are controlled based on the calculated misalignment amount, and the correction roller 31 is moved in the width direction (in the direction of arrow S3 or arrow S4 in FIG. 13). At the same time, "second correction" is performed to correct the misalignment of the paper P by rotating it in the direction of rotation in the paper transport surface (in the direction of arrow W3 or the direction of arrow W4 in FIG. 13) (S5 in FIG. 15). ).

In this way, even after the return operation (first correction), the misalignment of the paper P is detected (second position detection), and the misalignment of the paper P is corrected based on the detection result (second correction). ), The misalignment that occurs while the paper P is being conveyed by the correction roller 31 can be eliminated. Further, if the paper is passing through both the second CIS 102 and the third CIS 103, the misalignment detection (second position detection) after such a return operation may be performed a plurality of times at predetermined intervals. it can. Therefore, in the present embodiment, such misalignment detection (second position detection) is repeated until the paper P reaches the paper receiving position A of the delivery cylinder 8, and the misalignment correction (second correction) is performed each time. ) (S4 to S7 in FIG. 15).

By the way, after performing the second correction, the correction roller 31 feeds the paper P at the timing when the gripper 16 of the transfer cylinder 8 reaches the paper receiving position A, as shown in FIGS. 14A and 14B. It is transported to the receiving position A. At this time, ideally, as shown in FIG. 16, the roller shaft 31M of the correction roller 31 is arranged in the direction H of the home position orthogonal to the ideal transport direction X. Is desirable. However, in reality, when the second correction is completed due to an error in the rotational drive of the correction roller 31 in the paper transport surface or slippage between the correction roller 31 and the paper. As shown in FIG. 17, the correction roller 31 may not be arranged in the home position orientation H. In this way, when the roller shaft 31M of the correction roller 31 is arranged in a state of being inclined with respect to the direction H of the home position, the transport direction Xr by the correction roller 31 becomes oblique with respect to the ideal transport direction X. As shown by the alternate long and short dash line in FIG. 17, the paper P is displaced from the ideal position in the width direction Y with the transfer.

Further, in the present embodiment, the detection results of the two CIS are required for the calculation of the amount of skewing of the paper, and as shown in FIG. 17, the rear end Pc of the paper P is the second CIS 102. After passing through, the position of the paper can be detected only by the third CIS103 at the most downstream, so that the second correction based on the CIS detection result cannot be performed. Therefore, in the present embodiment, if the paper P is conveyed in a state where the correction roller 31 is tilted with respect to the orientation H of the home position after the completion of the second correction, a deviation in the width direction corresponding to the transfer distance occurs. .. Specifically, the amount of misalignment B in the width direction of the paper generated at this time is the inclination angle θ of the roller shaft 31M of the correction roller 31 with respect to the orientation H of the home position, and the rear end portion Pc of the paper P is the second CIS 102. It is obtained based on the following equation (1) from the value of the transport distance A from passing through to passing through the correction roller 31.

B = Atan θ ... (1)

Therefore, in the present embodiment, the position deviation amount B in the width direction of the paper caused by the inclination of the correction roller 31 is calculated, and the position of the correction roller 31 in the width direction is corrected based on the position deviation amount B. (S6 in FIG. 15). Hereinafter, a method of correcting the position of the correction roller 31 in the width direction will be described.

First, when the second correction (all the second corrections when the second correction is performed a plurality of times) is completed, the width direction deviation amount calculation unit 22 (see FIG. 6) determines the correction roller 31 with respect to the orientation H of the home position. The information of the inclination angle θ of is acquired. In the present embodiment, the width direction deviation amount calculation unit 22 uses the rotary encoder 58 as a tilt detecting means for detecting the rotation amount and the rotation direction of the correction roller 31 in the paper transport surface to correct the correction roller with respect to the home position direction H. The information of the inclination angle θ of 31 is acquired. Then, the width direction deviation amount calculation unit 22 uses the above equation 1 based on the inclination angle θ of the correction roller 31 and the previously input transfer distance A from the second CIS 102 to the correction roller 31 in the width direction. The misalignment amount B of is calculated.

Then, based on the calculated misalignment amount B in the width direction, the correction roller 31 is moved to one side in the width direction by the calculated misalignment amount B. Specifically, as shown in FIG. 18, when the correction roller 31 is tilted clockwise (Z1 direction) with respect to the home position direction H, the misalignment of the paper P in the width direction is upward in the figure. Since it occurs toward the direction, the correction roller 31 is moved in the opposite downward direction (Y1 direction) by the calculated misalignment amount B. On the contrary, as shown in FIG. 19, when the correction roller 31 is tilted counterclockwise (Z2 direction) with respect to the home position direction H, the misalignment in the width direction of the paper is in the lower part of the figure. Since it occurs toward the direction, the correction roller 31 is moved in the opposite upward direction (Y2 direction) by the calculated misalignment amount B.

In short, as shown in FIG. 18 or FIG. 19, when the correction roller 31 is tilted in any of the rotation directions in the paper transport surface with respect to the orientation H of the home position, the roller shaft of the correction roller 31 A misalignment of the paper P occurs in the roller transport direction Xr (actual transport direction), which is a direction orthogonal to 31M. In other words, when the roller transport direction Xr is tilted toward either end of the width direction of the paper P (in FIG. 18, the roller transport direction Xr is the end of the paper P in the figure). It is tilted toward the upper end side, and in FIG. 19, the roller transport direction Xr is tilted toward the lower end side of the figure among both ends of the paper P), and the roller transport direction Xr is tilted. The position of the paper P is displaced on the edge side of the paper. Therefore, in order to correct the misalignment of the paper P in the width direction due to the inclination of the correction roller 31, the correction roller 31 is placed in the width direction opposite to the direction in which the roller transfer direction Xr is inclined with respect to the ideal transfer direction X. Alternatively, the roller transport direction Xr may be moved in the width direction opposite to the direction in which the roller transport direction Xr is tilted toward either end of the width direction of the paper P. If the correction roller 31 is not tilted with respect to the orientation H of the home position at the time when the second correction is completed, the position shift in the width direction of the paper due to the transportation of the correction roller 31 does not occur, so that the correction roller does not occur. It is not necessary to correct the position in the width direction of 31.

As a method of moving the correction roller 31 in the width direction, the correction roller 31 may be instantaneously moved in the width direction at a predetermined timing after the rear end portion Pc of the paper P has passed through the second CIS 102. The correction roller 31 may be moved in the width direction at a substantially uniform speed while the correction roller 31 is conveying the paper P. Further, while the correction roller 31 conveys the paper P, the correction roller 31 is moved in the width direction while changing the moving speed in the width direction (for example, changing in the order of acceleration, constant velocity, and deceleration). You may.

As described above, in the present embodiment, the amount of displacement of the paper P in the width direction caused by the inclination of the correction roller 31 is calculated as the amount of movement of the correction roller 31 in the width direction to be corrected, and the calculated position is calculated. By moving the correction roller 31 in the direction of canceling the misalignment in the width direction based on the amount of misalignment, it is possible to eliminate the misalignment in the width direction of the paper P. As a result, the paper P can be conveyed from the correction roller 31 to the transfer cylinder 8 with high accuracy, and the image can be formed on the paper P with high accuracy. Further, when double-sided printing is performed, it is possible to eliminate the relative positional deviation between the front side image and the back side image.

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

In the above-described embodiment, the direction H orthogonal to the ideal transport direction X is set as the home position orientation H, but the home position orientation H can be arbitrarily set.

Further, the position detecting means for detecting the position of the side edge of the paper is not limited to CIS, and any other means such as a photo sensor arranged along the width direction of the paper, as long as it can detect the side edge of the paper. Detection means may be used.

Further, the transport device according to the present invention is applicable not only to the inkjet image forming device as shown in FIG. 1 but also to the electrophotographic image forming device.

FIG. 20 shows an example in which the transport device according to the present invention is applied to an electrophotographic image forming device.

As shown in FIG. 20, the electrophotographic image forming apparatus 300 includes an image forming unit 301 that forms an image on paper P, a document reading unit 302 that optically reads image information of the document D, and a set document D. A document transporting unit 310 that conveys the image to the document reading unit 302, a paper feeding unit (paper cassette) 312-314 in which the paper P is stored, a fixing device 320 that fixes an unfixed image on the paper P, and feeding. It is provided with a transport device 330 that transports the paper P fed from the units 312 to 314 to the image forming unit 301. Further, the image forming unit 301 has a photoconductor drum 305, an exposure unit 303 that irradiates the exposure light L onto the photoconductor drum 305 based on the image information read by the document reading unit 302, and toner on the photoconductor drum 305. It includes a developing unit 304 that forms an image (image), a transfer unit 307 that transfers a toner image formed on the photoconductor drum 305 to paper P, and the like.

The basic operation of the electrophotographic image forming apparatus 300 will be briefly described.

When the document D is transported by the document transport section 310 in the direction of the arrow in FIG. 20 and the image information of the document D is read by the document reading section 302, the charged surface on the photoconductor 305 from the exposure section 303 is based on the image information. Is irradiated with the exposure light L, and an electrostatic latent image is formed on the photoconductor drum 305. Subsequently, toner is supplied from the developing unit 304 to the electrostatic latent image on the photoconductor 305 to form a toner image (visible image). Further, the paper P fed from any of the paper feed units 312 to 314 is conveyed to the transfer unit 307 by the transfer device 330, and the toner image formed on the photoconductor 305 is transferred onto the paper P. After that, the paper P is conveyed to the fixing device 320, the toner image is fixed, and then the paper P is discharged to the outside of the device.

In such an electrophotographic image forming apparatus 300, it is required that the paper P is accurately conveyed to the transfer unit 307 by the conveying device 330 at the same timing as the toner image on the photoconductor drum 305. Therefore, also in such a transport device 330, similarly to the transport device 7 according to the above-described embodiment, after the correction roller 31 corrects the position of the paper (second correction), the correction roller 31 with respect to the predetermined home position By detecting the tilt in the rotation direction in the paper transport surface and controlling the amount of movement of the correction roller 31 in the paper width direction based on the detected tilt of the correction roller 31, the position shift of the paper P in the width direction It becomes possible to convey the paper P with high accuracy by eliminating the above.

Further, the transport device according to the present invention is applicable not only to an image forming device but also to a post-processing device that performs post-processing such as stapling processing and folding processing on paper on which an image is formed.

FIG. 21 shows an example in which the transport device according to the present invention is applied to a post-processing device.

The post-processing device 400 shown in FIG. 21 includes a punching device 410 that punches paper, a staple processing device 420 that performs binding processing on paper, a folding processing device 430 that performs center-folding processing on paper, and a plurality of trays ( The loading unit) 441, 442, 443 and a transport device 450 that transports the paper transported from the image forming apparatus 100 to the punching device 410. The post-processing apparatus 400 conveys the paper conveyed from the image forming apparatus 100 to one of the three transfer paths J1 to J3, and performs different post-processing.

The first transport path J1 is a path for transporting the paper punched by the punching device 410 or the paper not punched to the first tray 441. The second transport path J2 is a path for transporting the paper to the staple processing apparatus 420 and transporting the bound paper to the second tray 442. The third transport path J3 is a path for transporting the paper to the folding processing device 430 and conveying the middle-folded paper to the third tray 443.

Also in the transport device 450 provided in such a post-processing device 400, similarly to the transport device 7 according to the above-described embodiment, after the correction roller 31 corrects the position of the paper (second correction), a predetermined home is used. By detecting the inclination of the correction roller 31 in the rotation direction in the paper transport surface with respect to the position and controlling the amount of movement of the correction roller 31 in the paper width direction based on the detected inclination of the correction roller 31, the paper P It is possible to convey the paper P with high accuracy by eliminating the misalignment in the width direction of the paper P.

Further, the transport device according to the present invention is not limited to the transport device that transports the sheet for image formation. For example, the present invention can be applied to a transport device for transporting other sheets, such as a transport device for transporting a document and a transport device for transporting an electronic substrate.

2 Image forming unit 7 Conveying device 20 Control unit (control means)
31 Correction roller (correction means)
31M roller shaft 58 rotary encoder (tilt detection means)
100 Inkjet image forming apparatus 101 CIS (position detection means)
102 CIS (Position Detection Means)
103 CIS (Position Detection Means)
300 Electrophotographic image forming device 301 Image forming unit 330 Conveying device A Conveying distance from the second CIS to the correction roller B Displacement amount in the width direction of the paper H Home position orientation P Paper (sheet)
X Ideal transport direction Xr Roller transport direction θ Correction roller tilt angle

Japanese Unexamined Patent Publication No. 2018-16492

Claims (4)

Position detection means to detect the position of the seat and
While transporting the sheet, a correction means for correcting the position of the sheet in the rotation direction and the sheet width direction in the sheet transport surface according to the position of the sheet detected by the position detecting means.
After the correction means corrects the position of the sheet, the detection means for detecting the inclination of the correction means in the rotation direction in the sheet transport surface, and
A control means for controlling the correction means to move in the seat width direction based on the detected inclination of the correction means, and
A transport device characterized by comprising. After the rear end portion of the sheet passes through the specific position detecting means arranged on the upstream side in the transport direction from the correction means, the position of the sheet in the sheet transport surface in the sheet transport surface is not corrected without correction. A transport device for transporting the sheet.
The control means corrects the correction based on the transport distance from the time when the rear end portion of the sheet passes through the specific position detecting means to the time when the rear end portion passes through the correction means and the inclination of the detected correction means. The transport device according to claim 1, wherein the amount of movement of the means in the sheet width direction is calculated. The correction means is a correction roller.
In the control means, after the correction roller corrects the position of the sheet, the roller transport direction orthogonal to the roller axis of the correction roller is tilted toward one of both ends in the sheet width direction. The transport device according to claim 1 or 2, wherein the correction roller is moved in the seat width direction opposite to the direction in which the roller transport direction is tilted. The transport device according to any one of claims 1 to 3,
An image forming unit that forms an image on the sheet conveyed by the conveying device,
An image forming apparatus comprising.

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