JP7172766B2 - Conveying device and image forming device - Google Patents

Description

The present invention relates to a conveying device that conveys sheets, and an image forming apparatus that includes the conveying device.

2. Description of the Related Art Conveying devices for conveying sheets include, for example, conveying devices for conveying sheets such as paper and originals in image forming apparatuses such as copiers and printers.

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

In order to address this problem, Japanese Patent Application Laid-Open No. 2018-16492 discloses a technique in which a pair of correction rollers are used to correct the sheet while conveying the sheet so that the sheet can be conveyed with high accuracy without lowering productivity. A conveying device has been proposed that corrects sheet misalignment by moving a roller in a direction opposite to the sheet misalignment direction.

By the way, in the conventional conveying device, the sheet may be misaligned in the width direction due to the inclination of the correcting means.

In order to solve the above-mentioned problems, the present invention provides position detecting means for detecting the position of a sheet, and while conveying the sheet, in accordance with the position of the sheet detected by the position detecting means, in the sheet conveying plane. correction means for correcting the position of the sheet in the direction of rotation and the width direction of the sheet; and after the position of the sheet is corrected by the correction means, the inclination of the correction means in the direction of rotation within the sheet conveying plane is detected. and a control means for controlling the correction means to move in the sheet width direction based on the detected inclination of the correction means.

According to the present invention, it is possible to prevent misalignment of the sheet in the width direction due to the tilt of the correcting means.

1 is a schematic configuration diagram of an inkjet image forming apparatus according to an embodiment of the present invention; FIG. It is a top view of the conveying apparatus which concerns on this embodiment. FIG. 4 is a side view of a drive mechanism that drives a correction roller; FIG. 3 is a plan view of a drive mechanism that drives a correction roller; (a) is a diagram showing a state in which the holding frame moves only in the width direction, (b) is a diagram showing a state in which the holding frame moves only in the rotational direction within the paper transport plane, and (c) is a diagram showing the state in which the holding frame moves in the width direction. FIG. 10 is a diagram showing a state in which the roller has moved in both directions of the sheet conveying plane and the rotational direction in the sheet conveying plane; It is a block diagram showing a control system of the conveying device according to the present embodiment. FIG. 10 is a diagram for explaining a method of calculating a sheet misalignment amount; FIG. 10 is a diagram for explaining a method of calculating a sheet misalignment amount; It is a figure which shows the movement of the conveying apparatus which concerns on this embodiment, Comprising: (a) is a top view, (b) is a side view. It is a figure which shows the movement of the conveying apparatus which concerns on this embodiment, Comprising: (a) is a top view, (b) is a side view. It is a figure which shows the movement of the conveying apparatus which concerns on this embodiment, Comprising: (a) is a top view, (b) is a side view. It is a figure which shows the movement of the conveying apparatus which concerns on this embodiment, Comprising: (a) is a top view, (b) is a side view. It is a figure which shows the movement of the conveying apparatus which concerns on this embodiment, Comprising: (a) is a top view, (b) is a side view. It is a figure which shows the movement of the conveying apparatus which concerns on this embodiment, Comprising: (a) is a top view, (b) is a side view. It is a figure which shows the flowchart of a conveyance operation. FIG. 5 is a plan view showing a state in which the correction roller is arranged in the direction of the home position; FIG. 10 is a plan view showing a state in which the correction roller is arranged to be inclined with respect to the orientation of the home position; FIG. 8 is a plan view showing a state in which the correction roller is moved to one side in the width direction based on the calculated positional deviation amount; FIG. 11 is a plan view showing a state in which the correction roller is moved in the other width direction based on the calculated positional deviation amount; 1 is a diagram showing an example in which a conveying device according to the present invention is applied to an electrophotographic image forming apparatus; FIG. It is a figure which shows the example which applied the conveying apparatus which concerns on this invention to a post-processing apparatus.

The present invention will be described below with reference to the accompanying drawings. In addition, in each drawing for explaining the present invention, constituent elements such as members and constituent parts having the same function or shape are given the same reference numerals as much as possible, and once explained, the explanation will be repeated. omitted.

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

[overall structure]
An ink jet image forming apparatus 100 according to this embodiment mainly includes a paper feed section 1 , an image forming section 2 , a drying section 3 and a paper discharge section 4 . In the inkjet image forming apparatus 100 , an image is formed in the image forming section 2 with ink, which is a liquid for image formation, on a sheet of paper P supplied from the paper feeding section 1 . After drying the ink adhering to the paper P in the drying unit 3 , the paper P is discharged from the paper discharge unit 4 . In the case of double-sided printing, after an image is formed on the front side of the sheet P in the image forming section 2, the drying section 3 performs a drying process and conveys the sheet P to the reverse conveying path 150 without discharging the sheet. do. By passing through the reversing conveyance path 150, the paper P is supplied to the image forming section 2 again in a state where the front and back are reversed, and after an image is formed on the back surface of the paper P in the image forming section 2, it is sent to the drying section. Drying processing is performed in 3 and the paper is discharged from the paper discharge unit 4 .

[Paper feed section]
The paper feeding unit 1 mainly includes a paper feeding tray 5 on which a plurality of papers P are stacked, a feeding device 6 for separating and feeding the papers P one by one from the paper feeding tray 5, and a and a conveying device 7 for conveying the sheet P that has been picked up. As the feeding device 6, it is possible to use any feeding device such as a device using rollers or rollers, or a device using air suction. The sheet P sent out from the sheet feeding tray 5 by the feeding device 6 is transported to the image forming section 2 by the transporting device 7 .

[Image forming unit]
The image forming section 2 mainly includes a transfer drum 8 as a first conveying rotating body that receives the fed paper P and transfers it to the paper carrying drum 9, and the paper P conveyed by the transfer drum 8 on the outer peripheral surface. A paper carrier drum 9 as a second transport rotating body that carries and transports the paper P, an ink ejection unit 10 that ejects ink toward the paper P carried by the paper carrier drum 9 , and the paper transported by the paper carrier drum 9 . It is composed of a transfer cylinder 11 as a third conveying rotating body for transferring the paper P to the drying section 3 . The transfer drum 8 on the upstream side, the paper carrying drum 9, and the transfer drum 11 on the downstream side also serve as a part of the conveying device 7 for conveying the paper P.

The paper P conveyed from the paper feeding unit 1 to the image forming unit 2 is gripped at its leading end by a swingable gripper 16 as a receiving unit provided on the surface of the transfer cylinder 8, and is moved by the movement of the surface of the transfer cylinder 8. transported with it. The paper P conveyed by the transfer drum 8 is transferred to the paper carrying drum 9 at a position facing the paper carrying drum 9 . Although only one gripper 16 is shown in the example shown in FIG. 1, a plurality of grippers 16 may be provided on the transfer drum 8.

A similar gripper is provided as a receiving portion on the surface of the paper carrying drum 9, and the leading edge of the paper is gripped by the gripper. A plurality of suction holes are formed in a dispersed manner on the surface of the paper carrying drum 9 , and a suction device 12 generates a suction air current toward the inside of the paper carrying drum 9 in each of the suction holes. The paper P transferred from the transfer drum 8 to the paper carrying drum 9 is gripped by the gripper at the leading end, is attracted to the surface of the paper carrying drum 9 by the suction air current, and is moved along with the movement of the surface of the paper carrying drum 9. be transported.

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

The ejection operations of the liquid ejection heads 10C, 10M, 10Y, and 10K of the ink ejection section 10 are controlled by drive signals corresponding to image information. When the paper P carried on the paper carrying drum 9 passes through the area facing the ink ejection section 10, the liquid ejection heads 10C, 10M, 10Y, and 10K eject inks of respective colors, and an image corresponding to the image information is produced. It is formed. Note that, in the present embodiment, the image forming section 2 is not limited in its configuration as long as it forms an image by depositing liquid on the paper P. FIG.

[Drying part]
The drying unit 3 is mainly composed of a drying mechanism 13 for drying ink adhered on the paper P in the image forming unit 2 and a transport mechanism 14 for transporting the paper P transported from the image forming unit 2. It is The paper P conveyed from the image forming section 2 is received by the conveying mechanism 14 , conveyed so as to pass through the drying mechanism 13 , and delivered to the paper discharging section 4 . When the paper P passes through the drying mechanism 13, the ink on the paper P is subjected to a drying treatment. is suppressed.

[Paper output part]
The paper discharge section 4 mainly includes a paper discharge tray 15 on which a plurality of sheets P are stacked. The sheets P conveyed from the drying section 3 are sequentially stacked and held on the discharge tray 15 . Note that, in the present embodiment, the configuration of the paper ejection unit 4 is not limited as long as it ejects the paper P.

[Other additional functions]
The inkjet image forming apparatus 100 according to the present embodiment includes a paper feeding section 1, an image forming section 2, a drying section 3, and a paper discharging section 4, but other functional sections may be added as appropriate. For example, a preprocessing unit for performing preprocessing for image formation may be added between the paper feeding unit 1 and the image forming unit 2, or post-processing for image formation may be performed between the drying unit 3 and the paper discharge unit 4. Processing units can be added.

Examples of the pretreatment unit include those that perform a treatment liquid coating process for applying a treatment liquid to the paper P for suppressing bleeding by reacting with ink, but there are no particular restrictions on the content of the pretreatment. . Further, as a post-processing unit, for example, a paper reversal conveying process for reversing the paper P on which an image is formed in the image forming unit 2 and feeding it again to the image forming unit 2 to form images on both sides of the paper P, , binding a plurality of sheets of paper P on which images have been formed, and the like, but there are no particular restrictions on the content of the post-processing.

Note that the "image" formed on the paper is not limited to visualizing significant images such as characters and graphics, and includes, for example, patterns that have no meaning per se. In addition, the "sheet" on which the image is formed is not limited in material, and can be made of paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc., to which liquid can adhere even temporarily. For example, it may be used for film products, cloth products such as clothing, building materials such as wallpaper and flooring, and leather products. Further, the "liquid" is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head, but the viscosity is 30 mPa s or less at normal temperature and pressure, or by heating or cooling. Preferably. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional-imparting materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium. , edible materials such as natural pigments, and the like, which can be used for applications such as inkjet inks and surface treatment liquids.

Further, the "inkjet image forming apparatus" includes an apparatus in which a liquid ejection head and a sheet material move relatively, but is not limited to this. Specific examples include a serial type apparatus in which the liquid ejection head is moved and a line type apparatus in which the liquid ejection head is not moved.

A "liquid ejection head" is a functional component that ejects and ejects liquid from ejection holes (nozzles). Piezoelectric actuators (laminated piezoelectric element and thin film piezoelectric element), thermal actuators using electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a vibration plate and a counter electrode are used as energy sources for liquid ejection. Energy generating means can be used, but the ejection energy generating means to be used is not limited.

Next, the conveying device 7 included in the sheet feeding unit 1 according to this embodiment will be described.

FIG. 2 is a plan view of the conveying device according to this embodiment.

As shown in FIG. 2, the conveying device 7 includes three CISs 101 to 103 as position detection means for detecting the position of the conveyed paper P, and changes the position of the paper P while conveying it. and a pair of upstream rollers 44 as upstream conveying means arranged upstream of the correcting roller 31 in the conveying direction. In the following description, the plurality of CISs 101 to 103 are, in order from the upstream side in the paper transport direction, a first CIS (first position detection means) 101, a second CIS (second position detection means) 102, and a third CIS. It will be called CIS (third position detecting means) 103 .

In recent years, CIS uses a small-shaped LED (Light Emitting Diode) as a light source for the purpose of miniaturizing the device, and a contact image sensor (Contact Image) that directly reads an image with a linear sensor through a lens. Sensor). Each of the CISs 101 to 103 can detect a side edge Pa on one side of the paper P in the width direction by using a plurality of line sensors provided in the width direction of the paper P. FIG. In this specification, "paper width direction" or "width direction" means a direction perpendicular to or crossing the ideal paper transport direction X (see FIG. 16) within the paper transport plane. . The first CIS 101 is arranged upstream of the upstream roller 44 in the conveying direction, 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 drum 8 as a downstream conveying means arranged further downstream in the conveying direction. Also, the CISs 101 to 103 are arranged parallel to the width direction of the paper P. As shown in FIG.

The pair of correction rollers 31 move in the width direction of the paper P (the direction of the arrow S in FIG. 2) while nipping the paper P being conveyed, or move around the support shaft 73 within the paper conveyance plane (see FIG. 2 The position of the paper P is changed by rotating (in the direction of the arrow W in the middle). As a result, the positional deviation α in the width direction of the sheet P and the positional deviation β in the oblique feeding direction are corrected. In this embodiment, the support shaft 73 is provided at one axial end of the correction roller 31 , but the support shaft 73 may be provided at the center position of the correction roller 31 in the axial direction.

3 and 4 show the configuration of a drive mechanism for driving the correction roller. 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 to rotate therewith. These correction rollers 31 are rotatably held about the roller shafts by a holding frame 72 as a holding member. The holding frame 72 is supported by a base frame 71 fixed to the 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. Thus, the holding frame 72 is configured to be movable in any direction within the paper transport plane (sheet transport plane) along the upper surface of the base frame 71 . By supporting the holding frame 72 using the free bearings 95 in this way, the friction load when the holding frame 72 moves can be made extremely small. As a result, sheet misalignment correction, which will be described later, can be performed at high speed and with high accuracy. In this 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 serves as the center of rotation of the correction roller 31 in the sheet conveying plane, so as to extend downward. A lower end portion of the support shaft 73 is inserted into a width direction guide portion 71 a formed in the base frame 71 . The width direction guide portion 71a is a hole formed 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 through the guide roller 79 so as to come into contact with the width direction guide portion 71a. As 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 thereon also move in the width direction. The holding frame 72 is also configured to rotate (in the direction of arrow W in FIG. 4) within the paper transport plane about the support shaft 73 . As the holding frame 72 rotates around the support shaft 73, the correction roller 31 rotates within the sheet conveying plane.

As shown in FIG. 3, a bracket 69 provided on the right end side of the main body frame 70 in the figure has a transport driving motor (transport driving means) 61 that imparts driving force to the correction roller 31 for transporting the paper. is provided. The transport drive motor 61 and the drive roller 31 a of the correction roller 31 are connected 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 when the rotation shaft of the drive roller 31a and the rotation shaft of the gear 67 are separated from each other in the axial direction, come close to each other, or are driven in mutually inclined directions. It is a two-stage spline coupling. Since the driving roller 31a and the gear 67 are connected via the coupling mechanism 65 in this manner, the correction roller 31 moves in the width direction and rotates in the paper conveying plane, thereby moving the driving roller 31a. Even if the relative position with respect to the transport drive motor 61 changes, the driving force can be transmitted satisfactorily from the transport drive motor 61 to the drive roller 31a.

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

Further, the conveying device 7 according to the present embodiment includes a width direction driving mechanism 38 that moves the holding frame 72 and the correction roller 31 in the width direction of the paper, and a width direction driving mechanism 38 that moves the holding frame 72 and the correction roller 31 in the rotation direction within the paper conveying plane. and an oblique direction driving mechanism 39 for rotating.

As shown in FIGS. 3 and 4, the width direction driving mechanism 38 is composed of a width direction driving motor (width direction driving 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 bias the holding frame 72 in one width direction (left direction in FIG. 4). The cam 45 is provided on the base frame 71 so as to be rotatable around its rotary shaft 45a. The cam 45 is held in contact with a cam follower 46 provided on the support shaft 73 by the biasing force of the tension spring 59 . When the cam 45 rotates, the cam follower 46 is pushed against the biasing force of the tension spring 59, thereby moving the holding frame 72 in the width direction (rightward in FIG. 4).

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

As shown in FIGS. 3 and 4, the skew direction driving mechanism 39 includes a skew direction driving motor (skew direction driving 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 bias the holding frame 72 in one oblique direction (clockwise around the support shaft 73 in FIG. 4). The cam 47 is provided on the base frame 71 so as to be rotatable around its rotary shaft 47a. The cam 47 is held in contact with a cam follower 48 provided at one end of the lever member 50 by the biasing force of the tension spring 60 . A working roller 49 is rotatably provided at the opposite end of the lever member 50 . The action roller 49 is held in contact with a protrusion 72 a provided on the holding frame 72 by the biasing 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 its rotation axis 50a. Accordingly, the action roller 49 provided on the lever member 50 pushes the projection 72a of the holding frame 72 against the biasing force of the tension spring 60, so that the holding frame 72 rotates in the paper conveying plane. Rotate (counterclockwise in FIG. 4).

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

FIG. 5(a) shows a state in which only the cam 45 of the width direction driving mechanism 38 rotates and the holding frame 72 moves in the width direction, and FIG. 5(b) shows the oblique direction driving mechanism. Only the cam 47 of 39 is rotated, and the holding frame 72 is rotated within the sheet conveying plane. FIG. 5(c) shows a state in which both the cams 45 and 47 are rotated, and the holding frame 72 is moved in the width direction and rotated within the sheet conveying plane.

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

The conveying apparatus according to the present embodiment includes a control unit 20 as control means for controlling the correction roller 31 to correct misalignment of the sheet. As shown in FIG. 6, the control unit 20 includes a positional deviation amount calculation unit 21 that calculates the positional deviation amount of the paper from the detection results of the CISs 101 to 103, and a width direction deviation amount calculation unit 22 for calculating the amount. The control unit 20 controls the width direction driving motor 62 and the skew feed motor 62 based on the amount of misalignment of the paper calculated by the misalignment amount calculation unit 21 and the amount of misalignment in the width direction calculated by the misalignment amount calculation unit 22 . The drive of the direction drive motor 63 is controlled to drive the correction roller 31 in the width direction and the rotation direction within the sheet conveying plane.

7 and 8, a method of calculating the amount of sheet misalignment based on the detection results of the CISs 101 to 103 will be described.

As shown in FIG. 7, when the leading edge Pb of the paper P passes through the first CIS 101 and reaches the second CIS 102, the amount of misalignment α in the width direction of the paper P and the amount of misalignment β in the skewing direction are different. detected.

Specifically, the widthwise positional deviation amount α is calculated based on the widthwise position of the sheet P (the position of the side edge Pa of the sheet 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 positional deviation amount α of the paper P in the width direction.

Further, the skew positional deviation β is calculated from the difference in position of the sheet P in the width direction detected by the first CIS 101 and the second CIS 102 . That is, as shown in FIG. 7, when the leading edge Pb of the sheet P reaches the second CIS 102, the first CIS 101 and the second CIS 102 move the distances K1 and K2 in the width direction from the conveyance reference position K. is detected. Then, from these distances K1 and K2 and the preset distance M1 between the first CIS 101 and the second CIS 102, using the formula tanβ=(K1−K2)/M1, the skew is calculated.

In this manner, the widthwise positional deviation amount α and the oblique positional deviation amount β are calculated. As shown in FIG. 8, when the sheet is moved from the position P to the position P' by correcting the positional deviation of the skew, the positional deviation amount in the width direction changes from α to α'. Therefore, by calculating the positional deviation amount α' in the width direction in advance, it is possible to perform positional deviation correction with higher accuracy. However, the amount of positional deviation α′ in the width direction changes depending on which position is used as a reference for the skewed positional deviation correction.

As described above, the method of calculating the amount of sheet misalignment has been described using the first CIS 101 and the second CIS 102 as examples. can be detected.

The operation of the conveying apparatus according to this embodiment will be described below with reference to the flow charts of FIGS. 9 to 14 and 15. FIG.

As shown in FIGS. 9A and 9B, when the paper P is conveyed, the correction roller 31 is arranged at the home position where the roller axis is perpendicular to the conveying direction (horizontal direction in the drawing). there is Also, 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 leading edge Pb of the paper P passes through the first CIS 101 and reaches the second CIS 102, the first CIS 101 and the second CIS 102 move the paper. "First position detection" is performed to detect the position of the side end Pa of P (S1 in FIG. 15). Then, based on the positional information detected by these CISs 101 and 102, the positional deviation amount α in the width direction (or the positional deviation amount α' including the deviation amount accompanying the correction of the skewed positional deviation) and the skewed position are calculated. is calculated by the positional displacement amount calculator 21 (see FIG. 6). Then, based on the calculated positional deviation amount, the width direction driving motor 62 and the skew direction driving motor 63 are controlled to move the correction roller 31 in the width direction (in the direction of arrow S1 in FIG. 10) and to move the paper. Rotate in the direction of rotation within the transport plane (in the direction of arrow W1 in FIG. 10). As a result, a "welcoming operation" is performed in which the correction roller 31 faces the leading edge 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 start rotating, as shown in FIGS. 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 welcoming operation (arrow S2 direction and arrow W2 direction in the drawing) while conveying the paper P by the correction roller 31. A "return operation" is performed (S3 in FIG. 15). As a result, the "first correction" for correcting the positional deviation in the width direction and the skewed positional deviation of the paper P is performed.

Furthermore, as shown in FIGS. 13A and 13B, when the leading edge Pb of the paper P reaches the third CIS 103, the second CIS 102 and the third CIS 103 move the side edge Pa of the paper P again. "Second position detection" for detecting the position is performed (S4 in FIG. 15). Based on the positional information detected by these CISs 102 and 103, the positional deviation amount in the width direction and the skewed positional deviation amount are calculated by the positional deviation amount calculation unit 21. FIG. Then, the width direction driving motor 62 and the skew direction driving motor 63 are controlled based on the calculated positional deviation amount to move the correction roller 31 in the width direction (in the direction of arrow S3 or arrow S4 in FIG. 13). 13) to correct the positional deviation of the paper P (S5 in FIG. 15). ).

In this way, even after the returning operation (first correction), the positional deviation of the paper P is detected (second position detection), and based on the detection result, the positional deviation of the paper P is corrected (second correction ), it is possible to eliminate the positional deviation that occurs while the sheet P is conveyed by the correction roller 31 . Further, positional deviation detection (second position detection) after such return operation can be performed multiple times at predetermined intervals if the paper is passing through both the second CIS 102 and the third CIS 103. can. Therefore, in the present embodiment, such positional deviation detection (second position detection) is repeatedly performed until the paper P reaches the paper receiving position A of the transfer cylinder 8, and positional deviation correction (second correction) is performed each time. ) is performed (S4 to S7 in FIG. 15).

By the way, after performing the second correction, the correction roller 31 adjusts the paper P to the timing when the gripper 16 of the transfer cylinder 8 reaches the paper receiving position A, as shown in FIGS. 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 conveying direction X. is desirable. However, in reality, when the second correction is completed, for reasons such as an error in the rotational driving of the correction roller 31 within the paper conveying surface, slippage between the correction roller 31 and the paper, etc., As shown in FIG. 17, there are cases where the correction roller 31 is not arranged in the direction H of the home position. In this manner, when the roller shaft 31M of the correction roller 31 is arranged in a state inclined with respect to the direction H of the home position, the conveying direction Xr by the correcting roller 31 becomes oblique with respect to the ideal conveying direction X. As indicated by the two-dot chain line in FIG. 17, the paper P is displaced in the width direction Y from the ideal position as it is conveyed.

Further, in the present embodiment, the detection results of two CISs are required to calculate the amount of skewed feeding of the paper, but as shown in FIG. , the position of the sheet can be detected only by the third CIS 103 at the most downstream side, so the second correction based on the detection result of the CIS cannot be performed. Therefore, in the present embodiment, if the paper P is conveyed in a state in which the correction roller 31 is tilted with respect to the direction H of the home position after the second correction is completed, a widthwise deviation occurs according to the conveying distance. . Specifically, the amount of positional deviation B in the width direction of the paper that occurs at this time is determined by the inclination angle θ of the roller shaft 31M of the correction roller 31 with respect to the direction H of the home position, and from the value of the conveying distance A from passing through the correction roller 31 to passing through the correction roller 31 based on the following formula (1).

B=Atan θ (1)

Therefore, in the present embodiment, the positional deviation amount B in the width direction of the sheet 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 positional deviation amount B. (S6 in FIG. 15). A method of correcting the width direction position of the correction roller 31 will be described below.

First, when the second correction (all the second corrections if the second correction is performed multiple times) is completed, the width direction deviation amount calculator 22 (see FIG. 6) calculates the correction roller 31 relative to the direction H of the home position. acquires information on the inclination angle θ of In this embodiment, the width direction deviation amount calculation unit 22 detects the rotation amount and the rotation direction of the correction roller 31 in the sheet conveying surface from the rotary encoder 58 as an inclination detection means for detecting the correction roller relative to the orientation H of the home position. 31 is acquired. Then, the width direction shift amount calculation unit 22 calculates the width direction deviation using the above equation 1 based on the tilt angle θ of the correction roller 31 and the pre-input conveying distance A from the second CIS 102 to the correction roller 31 . is calculated.

Then, based on the calculated positional deviation amount B in the width direction, the correction roller 31 is moved in one direction in the width direction by the calculated positional deviation amount B. FIG. Specifically, as shown in FIG. 18, when the correction roller 31 is tilted clockwise (Z1 direction) with respect to the direction H of the home position, the positional deviation of the paper P in the width direction is shifted upward in the drawing. Therefore, the correction roller 31 is moved in the opposite downward direction (Y1 direction) by the calculated positional deviation amount B. FIG. On the contrary, as shown in FIG. 19, when the correction roller 31 is tilted counterclockwise (Z2 direction) with respect to the orientation H of the home position, the misalignment in the width direction of the paper is downward in the drawing. Therefore, the correction roller 31 is moved in the opposite upward direction (Y2 direction) by the calculated positional deviation amount B. FIG.

In short, as shown in FIG. 18 or 19, when the correction roller 31 is inclined in one of the rotation directions in the sheet conveying plane with respect to the direction H of the home position, the roller axis of the correction roller 31 Positional deviation of the paper P occurs in the roller transport direction Xr (actual transport direction), which is a direction orthogonal to 31M. In other words, if the roller conveying direction Xr is inclined toward one of both ends of the paper P in the width direction (in FIG. 18, the roller conveying direction Xr In FIG. 19, the roller conveying direction Xr is inclined toward the lower end of the drawing among both ends of the paper P), and the roller conveying direction Xr is inclined. A positional deviation of the paper P occurs on the side of the paper edge where the paper P is located. Therefore, in order to correct the positional deviation of the sheet P in the width direction due to the inclination of the correction roller 31, the correction roller 31 is moved in the width direction opposite to the direction in which the roller conveying direction Xr is inclined with respect to the ideal conveying direction X. Alternatively, it may be moved in the width direction opposite to the direction in which the roller transport direction Xr is inclined to one of the width direction ends of the paper P. Note that if the correction roller 31 is not tilted with respect to the direction H of the home position when the second correction is completed, no misalignment occurs in the width direction of the paper as the correction roller 31 is conveyed. There is no need to correct the widthwise position of 31.

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

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

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

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

In addition, the position detection means for detecting the position of the side edge of the paper is not limited to the CIS, but may be any device that can detect the side edge of the paper, such as a plurality of photosensors arranged along the width direction of the paper. detection means may be used.

Further, the conveying device according to the present invention is applicable not only to the ink jet image forming apparatus as shown in FIG. 1, but also to an electrophotographic image forming apparatus.

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

As shown in FIG. 20, an electrophotographic image forming apparatus 300 includes an image forming section 301 for forming an image on a sheet P, a document reading section 302 for optically reading image information of a document D, and a set document D. to the document reading unit 302, paper feed units (paper feed cassettes) 312 to 314 containing paper P, fixing device 320 for fixing unfixed images on paper P, paper feed and a conveying device 330 for conveying the sheet P fed from the sections 312 to 314 to the image forming section 301 . The image forming unit 301 also includes a photosensitive drum 305 , an exposure unit 303 that irradiates the photosensitive drum 305 with exposure light L based on image information read by a document reading unit 302 , and toner on the photosensitive drum 305 . A developing unit 304 that forms an image, a transfer unit 307 that transfers the toner image formed on the photosensitive drum 305 to the paper P, and the like are provided.

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

When the document D is conveyed by the document conveying section 310 in the direction of the arrow in FIG. is irradiated with the exposure light L, and an electrostatic latent image is formed on the photosensitive drum 305 . Subsequently, toner is supplied from the developing unit 304 to the electrostatic latent image on the photosensitive member 305 to form a toner image (visible image). Also, the paper P fed from any one of the paper feeding units 312 to 314 is conveyed to the transfer unit 307 by the conveying device 330, and the toner image formed on the photoreceptor 305 is transferred onto the paper P. FIG. After that, the paper P is transported to the fixing device 320, and after the toner image is fixed, the paper P is discharged outside the device.

In such an electrophotographic image forming apparatus 300, it is required that the conveying device 330 accurately conveys the sheet P to the transfer section 307 in time with the toner image on the photosensitive drum 305. FIG. Therefore, in the conveying device 330 as well, similarly to the conveying device 7 according to the above-described embodiment, after the correction roller 31 performs the sheet position correction (second correction), the correction roller 31 is moved to the predetermined home position. By detecting the inclination in the rotation direction in the paper transport plane 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, positional deviation in the width direction of the paper P is corrected. can be eliminated, and the paper P can be conveyed with high accuracy.

Further, the conveying device according to the present invention is applicable not only to image forming apparatuses but also to post-processing apparatuses that perform post-processing such as stapling and folding on sheets on which images have been formed.

FIG. 21 shows an example in which the conveying 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 for punching sheets, a stapling device 420 for binding sheets, a folding device 430 for center-folding sheets, and a plurality of trays ( stacking units 441 , 442 , 443 , and a conveying device 450 for conveying sheets conveyed from the image forming apparatus 100 to the punching device 410 . The post-processing device 400 conveys the sheet conveyed from the image forming apparatus 100 to one of the three conveying routes J1 to J3, and performs different post-processing.

The first transport path J<b>1 is a path for transporting a sheet that has been punched by the punching device 410 or a sheet that has not been punched to the first tray 441 . The second transport path J2 is a path for transporting the sheets to the stapling device 420 and transporting the bound sheets to the second tray 442 . The third transport path J3 is a path for transporting the sheet to the folding device 430 and transporting the center-folded sheet to the third tray 443 .

In the conveying device 450 provided in the post-processing device 400 as described above, similarly to the conveying device 7 according to the above-described embodiment, after the correction roller 31 performs the sheet position correction (second correction), By detecting the inclination of the correction roller 31 with respect to the position in the rotation direction within the paper transport plane 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 eliminate the positional deviation in the width direction of the paper P and convey the paper P with high accuracy.

Further, the conveying device according to the present invention is not limited to a conveying device that conveys sheets for image formation. For example, the present invention can also be applied to a conveying device that conveys other sheets, such as a conveying device that conveys a document or a conveying device that conveys an electronic substrate.

2 image forming section 7 conveying device 20 control section (control means)
31 correction roller (correction means)
31M roller shaft 58 rotary encoder (tilt detection means)
100 Ink Jet Image Forming Apparatus 101 CIS (Position Detection Means)
102 CIS (position detection means)
103 CIS (position detection means)
300 Electrophotographic image forming apparatus 301 Image forming unit 330 Conveying device A Conveying distance from the second CIS to the correction roller B Positional deviation amount in the width direction of paper H Orientation of home position P Paper (sheet)
X Ideal transport direction Xr Roller transport direction θ Inclination angle of correction roller

JP 2018-16492 A

Claims (4)

position detection means for detecting the position of the seat;
correcting means for correcting the position of the sheet in the rotational direction and the sheet width direction within the sheet conveying plane according to the position of the sheet detected by the position detecting means while conveying the sheet;
detection means for detecting an inclination of the correction means in a rotational direction within a sheet conveying plane after the correction means corrects the position of the sheet;
control means for controlling the correction means to move in the sheet width direction based on the detected inclination of the correction means;
A conveying device comprising: After the trailing edge of the sheet passes through the specific position detecting means arranged upstream in the conveying direction from the correcting means, the position of the sheet in the sheet conveying plane in the rotational direction is not corrected. A conveying device that conveys the sheet,
The control means performs the correction based on the conveying distance from when the trailing edge of the sheet passes through the specific position detection means to when it passes through the correction means and the detected inclination of the correction means. 2. The conveying 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,
The control means tilts the roller conveying direction orthogonal to the roller axis of the correction roller toward one of both ends in the width direction of the sheet after the correction roller corrects the position of the sheet. 3. The conveying device according to claim 1 or 2, wherein the correcting roller is moved in the sheet width direction opposite to the direction in which the roller conveying direction is inclined when the sheet is being conveyed. A conveying 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:

Images