JP2006290567A - Conveyance device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conveyance device having a pair of loop forming rollers for forming a loop on a paper sheet to perform oblique compensation of a tip and capable of preventing occurrence of wrinkle on the paper sheet. <P>SOLUTION: A driving roller 25 of the pair 16 of loop forming rollers has a driving shaft 27 and a plurality of roll bodies 28 surrounding the driving shaft 27. Each roll body 28 is mutually connected through a joint 29 so as to rotate integrally. A one-way clutch 30 is provided between the driving shaft 27 and the other roll body 28b. Since each roll body 28 is mutually connected by the joint 29 so as to rotate integrally, its rotation is stopped at the same timing to let amount of feed of paper sheet by each roll body 28 agree. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transport device for transporting paper.

  For example, an image forming apparatus such as a copying machine, a printer, or a facsimile is provided with a transport device for transporting paper from a paper feed cassette to an image forming area (for example, see Patent Document 1). Some conveying apparatuses include a registration roller pair and a loop forming roller pair provided on the upstream side of the registration roller pair (see, for example, Patent Document 2). The registration roller pair is for sending the paper toward the image forming area at a predetermined timing. At the time of image formation, the registration roller pair first receives the leading edge of the sheet conveyed from the sheet feeding cassette in a stopped state. Then, driving is started at a predetermined timing, and the sheet is conveyed to the image forming area on the downstream side.

  The pair of loop forming rollers performs correction (oblique correction) when the leading end of the sheet is inclined with respect to the width direction orthogonal to the conveyance direction of the sheet. Specifically, the loop forming roller pair forms a loop on the sheet by feeding a predetermined amount of the sheet whose leading end is received by the stopped pair of registration rollers. As a result, the entire leading edge of the sheet is received by the registration roller pair.

The loop forming roller pair that performs such an operation includes a driving roller and a driven roller. In Patent Document 2, the drive roller has a drive shaft and two roll bodies fitted on the drive shaft. The two roll bodies are arranged at an interval in the axial direction, and are respectively connected to the drive shaft via a one-way clutch.
With the above configuration, when the loop is formed on the paper, the two roll bodies rotate integrally with the drive shaft through the corresponding one-way clutch as the drive shaft rotates. On the other hand, when the sheet is being conveyed by the pair of registration rollers, the two roll bodies are rotated with the movement of the sheet and are idled with respect to the drive shaft so that the sheet can be conveyed smoothly.
JP-A-5-97279 JP-A-9-77310

  The two roll bodies are independently connected to the drive shaft via separate one-way clutches. For this reason, when the formation of the loop is completed and the drive of the drive shaft is stopped and the drive of the registration roller pair is stopped, the stop timing of the two roll bodies may be shifted. When the stop timing is deviated, the sheet feed amount differs between the two roll bodies, and the sheet is twisted. If the registration roller pair starts conveying the paper while the paper is twisted, the paper will be wrinkled.

Further, it is necessary to provide as many one-way clutches with high production cost as the number of roll bodies.
The present invention has been made under such a background, and an object of the present invention is to prevent wrinkling of a sheet in a conveying device having a pair of loop forming rollers.
Another object of the present invention is to provide a conveying apparatus with a low manufacturing cost.

  In order to achieve the above object, the invention according to claim 1 is provided on the upstream side of the registration roller pair (12) and the registration roller pair, and conveys the sheet (P) toward the registration roller pair and stops. In a conveying device (5) having a loop forming roller pair (16) for forming a loop (B) on a sheet whose leading edge is received by the registration roller pair therein, at least one of the loop forming roller pair (25) Is a support shaft (27), a plurality of roll bodies (28) surrounding the support shaft, arranged in a predetermined interval in the axial direction, and connected to each other so as to be integrally rotatable. A one-way clutch that is interposed between the shaft and one of the plurality of roll bodies (28b) and rotates the roll body in accordance with the rotation of the support shaft only when the support shaft is rotated in one direction. (30) A transfer device for a.

The alphanumeric characters in parentheses indicate corresponding components in the embodiments described later. The same applies hereinafter.
According to this structure, since each roll body is connected so that integral rotation is mutually possible, it can stop rotation at the same timing. Accordingly, when the driving of the pair of loop forming rollers is stopped and the formation of the loop on the paper is completed, the timing of stopping the rotation of each roll body is made coincident so that the amount of paper fed by each roll body is made coincident. be able to. Therefore, the paper is not twisted. As a result, it is possible to prevent the paper from being wrinkled when the paper is being conveyed by the registration roller pair. Further, only one one-way clutch having a high manufacturing cost is required, and the manufacturing cost can be reduced.

The invention according to claim 2 is characterized in that the adjacent roll bodies of the plurality of roll bodies are connected to each other via a cylindrical joint (29) surrounding the support shaft. It is a transport device.
According to this configuration, the joint can be configured with a simple shape, and the cost can be further reduced. Moreover, a joint can be arrange | positioned between adjacent roll bodies and the sheet | seat of the part between several roll bodies can be received by a joint. Thereby, the bending of the sheet | seat between adjacent roll bodies can be decreased. As a result, it is possible to more reliably prevent the paper from being wrinkled.

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a schematic configuration of a copying machine as an image forming apparatus provided with a conveying device according to an embodiment of the present invention. Note that the present invention may be applied to a conveyance device provided in another image forming apparatus such as a printer or a facsimile.
Referring to FIG. 1, a copying machine 1 is for forming a document image on a sheet P (recording medium) based on the read image data of a document, and includes a document reading unit 2, an image forming unit 3, and the like. It has. Arrows A1 and A2 in FIG. 1 indicate the conveyance direction of the paper P, respectively.

The document reading unit 2 is for reading a document and generating image data of the document. The image forming unit 3 is for forming a document image on the paper P based on the image data generated by the document reading unit 2.
The image forming unit 3 includes a paper storage unit 4, a paper conveyance path L1, a conveyance device 5, a photosensitive drum 6, a developing device 7, a transfer roller 8, a fixing device 9, a discharge roller device 10, And a discharge tray 11.

The image forming on the paper P in the copying machine 1 is performed as follows. That is, at the time of image formation, the paper P stored in the paper storage unit 4 is transported in the paper transport path L 1 and reaches the registration roller pair 12 of the transport device 5. The paper P that has reached the registration roller pair 12 is transported downstream in the transport direction A1 at a predetermined timing, and reaches the transfer position T.
The transfer position T corresponds to a contact portion (nip) between the photosensitive drum 6 and the transfer roller 8. An electrostatic latent image based on the image data generated by the document reading unit 2 is formed on the photosensitive drum 6, and the electrostatic latent image is developed with toner supplied from the developing device 7. Is formed.

  The paper P that has reached the transfer position T is sandwiched between the photosensitive drum 6 and the transfer roller 8, and the toner on the photosensitive drum 6 is transferred by the transfer bias of the transfer roller 8. Of the toner on the photosensitive drum 6, residual toner that has not been transferred to the paper P is removed from the photosensitive drum 6 by the cleaning device 13. The paper P that has passed the transfer position T is transported in the paper transport path L1 and reaches the fixing device 9.

The fixing device 9 includes a heat roller 14 and a pressure roller 15, and the paper P passes between contact portions (nips) between the heat roller 14 and the pressure roller 15. As a result, the paper P is heated and pressurized, and the transferred toner is fixed.
The paper P that has passed through the fixing device 9 is transported in the paper transport path L <b> 1 and reaches the discharge roller device 10. The paper P is discharged to the discharge tray 11 by the discharge roller device 10.

Further, the image forming unit 3 is further provided with a paper transport path L2, and duplex printing is possible. Specifically, when performing duplex printing, the paper P on which an image is formed on one side through the fixing device 9 or the like is sent to the discharge roller device 10 and switched back. As a result, the paper P is sent to the paper transport path L2 and transported along the transport direction A2.
The paper P transported in the paper transport path L2 is returned to the paper transport path L1 again. The paper P returned to the paper transport path L1 is in a state where the front surface and the back surface are reversed, and passes through the transfer position T and the like in the same manner as when an image is formed on the front surface. An image is formed on the sheet and discharged from the discharge roller device 10 to the discharge tray 11.

  FIG. 2 is an enlarged view of the periphery of the photosensitive drum 6 of FIG. 1 and 2, the transport device 5 is for transporting the paper P, which has been transported from the paper storage unit 4 in the paper transport path L1, toward the transfer position T, and is described above. The registration roller pair 12 and the loop forming roller pair 16 disposed on the upstream side of the registration roller pair 12 in the transport direction A1 are provided.

The registration roller pair 12 is for conveying the paper P toward the transfer position T at a predetermined timing, and includes a driving roller 17 and a driven roller 18 driven by driving of the driving roller 17.
The drive roller 17 includes a drive shaft 19 and a roll body 20 that is externally fitted to the drive shaft 19 so as to be integrally rotatable.

The drive shaft 19 extends in the width direction W (the direction orthogonal to the paper surface in FIG. 2) of the paper transport path L1, and is rotatably supported by the housing 21 of the image forming unit 3. The drive shaft 19 is rotationally driven by a motor (not shown).
The driven roller 18 includes a support shaft 22 and a roll body 23 that is externally fitted to the support shaft 22 and is rotatable.

The support shaft 22 is arranged in parallel with the drive shaft 19 and is supported by the housing 21 or the like. The roll body 23 is in contact with the roll body 20 of the drive roller 17.
A spring 24 as an elastic member is placed between the support shaft 22 of the driven roller 18 and the housing 21, and the driven roller 18 is urged toward the drive roller 17 by the urging force of the spring 24. . As a result, the roll body 23 of the driven roller 18 and the roll body 20 of the drive roller 17 are pressed against each other to form a nip N1.

  FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2 and shows a main part of the loop forming roller pair 16. 2 and 3, the loop forming roller pair 16 conveys the paper P toward the registration roller pair 12, and loops B on the paper P whose tip is received by the registration roller pair 12 that is stopped. By forming this, when the leading edge of the paper P is inclined with respect to the width direction W, the correction (oblique correction) is performed.

The loop forming roller pair 16 includes a driving roller 25 (one of the loop forming roller pair 16) and a driven roller 26 driven by driving of the driving roller 25.
The drive roller 25 connects a drive shaft 27 (support shaft), a plurality of (for example, two) roll bodies 28 surrounding the drive shaft 27, and adjacent roll bodies 28 of the plurality of roll bodies 28 so as to be integrally rotatable. And a one-way clutch 30 interposed between the drive shaft 27 and any one of the plurality of roll bodies 28.

The drive shaft 27 extends in the width direction W and is supported rotatably with respect to the housing 21. An output from an output shaft (not shown) of the motor is applied to one end of the drive shaft 27, and the drive shaft 27 is driven to rotate by driving the motor.
Each roll body 28 is externally fitted to an intermediate portion of the drive shaft 27, and one roll body 28 a and the other roll body 28 b are arranged at a predetermined interval in the axial direction of the drive shaft 27. .

Each roll body 28 includes an inner cylinder 31 and an outer cylinder 32. For example, the inner cylinder 31 is formed using a synthetic resin, and the outer cylinder 32 is formed using an elastic body such as rubber or sponge.
The inner peripheral surface of each inner cylinder 31 faces the outer peripheral surface of the drive shaft 27. The inner peripheral surface of the corresponding outer cylinder 32 is fitted on the outer peripheral surface of each inner cylinder 31.

FIG. 4 is a perspective view of the drive roller 25. With reference to FIG. 3 and FIG. 4, the joint 29 is a member that is disposed between one roll body 28 a and the other roll body 28 b and has an outer diameter smaller than the outer diameter of the roll body 28, It has a cylindrical shape surrounding the drive shaft 27.
The outer peripheral surface of the joint 29 faces the paper transport path L1 (see FIG. 2) so that the paper P passing through the paper transport path L1 can be received. The joint 29 is configured by using one or a plurality of members (two in this embodiment).

Specifically, the joint 29 includes a cylindrical first member 33 and a cylindrical second member 34. The first member 33 and the second member 34 are arranged in the axial direction of the drive shaft 27.
FIG. 5 is an exploded perspective view of a main part of the drive roller 25. Referring to FIGS. 3 and 5, the first member 33 is disposed adjacent to one roll body 28a. One end 33a of the first member 33 is partially cut away to form a recess 35.

One or a plurality of the recesses 35 (two in this embodiment) are provided, and are arranged at equal intervals in the circumferential direction of the first member 33. Each recess 35 is formed in a groove shape, and is open to the second member 34 side. A convex portion 36 is formed between one concave portion 35 and the other concave portion 35 of the one end portion 33a. The convex portion 36 protrudes toward the second member 34 side.
The other end portion 33b of the first member 33 is formed with a concave portion 35 and a convex portion 36 similarly to the one end portion 33a (in FIG. 5, only a part of each of the concave portion 35 and the convex portion 36 is illustrated. ). Each recessed part 35 of the other end part 33b is open | released by the one roll body 28a side. The convex part 36 protrudes to the one roll body 28a side.

The position of the convex portion 36 (concave portion 35) of the one end portion 33a and the position of the convex portion 36 (concave portion 35) of the other end portion 33b are a predetermined angle (for example, 90 °) with respect to the circumferential direction of the first member 33. ) Is just off.
The second member 34 has the same configuration as the first member 33. The positions of the first member 33 and the second member 34 in the circumferential direction are aligned.

Each recessed part 35 of the one end part 34a of the 2nd member 34 is open | released at the other roll body 28b side. Each convex part 36 of the one end part 34a of the second member 34 protrudes toward the other roll body 28b.
Each recess 35 of the other end 34b of the second member 34 is open to the first member 33 side. Each convex part 36 of the other end part 34b of the second member 34 protrudes toward the first member 33 side.

The one end portion 33a of the first member 33 and the other end portion 34b of the second member 34 are connected by fitting the concave portions 35 corresponding to the respective convex portions 36.
The connection between the first member 33 and one roll body 28a is as follows. That is, the convex part 37 and the recessed part 38 are formed in the internal peripheral surface 31a of the inner cylinder 31 of one roll body 28a. These convex portions 37 and concave portions 38 are arranged in the circumferential direction of one roll body 28a (in FIG. 5, only a part of the convex portions 37 and the concave portions 38 are shown). A plurality of convex portions 37 are formed corresponding to the concave portions 35 of the other end portion 33b of the first member 33, and are fitted into the concave portions 35 of the other end portion 33b. Similarly, a plurality of concave portions 38 are formed corresponding to the convex portions 36 of the other end portion 33b, and are fitted into the convex portions 36 of the other end portion 33b.

  The connection between the second member 34 and the other roll body 28b is as follows. That is, the convex part 37 and the recessed part 38 are formed in the inner peripheral surface 31a of the inner cylinder 31 of the other roll body 28b similarly to the inner peripheral surface 31a of the inner cylinder 31 of one roll body 28a. The convex portion 37 of the inner peripheral surface 31 a of the other roll body 28 b is fitted in the concave portion 35 of the one end portion 34 a of the second member 34. Similarly, the concave portion 38 of the inner peripheral surface 31 a of the other roll body 28 b is fitted into the convex portion 36 of the one end portion 34 a of the second member 34.

  The one-way clutch 30 is interposed between the drive shaft 27 and the other roll body 28b. More specifically, it is interposed between the outer peripheral surface 27a of the drive shaft 27 and the inner peripheral surface 31a of the inner cylinder 31 of the other roll body 28b. The one-way clutch 30 moves the other roll body 28b (each roll body 28) with the rotation of the drive shaft 27 only when the drive shaft 27 is rotationally driven in one of the circumferential directions (rotation direction R1). It is designed to rotate integrally.

A bearing 39 is interposed between the inner peripheral surface 31 a of the inner cylinder 31 of one roll body 28 a and the outer peripheral surface 27 a of the drive shaft 27, and the one roll body 28 a is relative to the drive shaft 27. It is rotatably supported.
Each roll body 28 and joint 29 of the drive roller 25 are sandwiched between a pair of retaining rings 40 and 41 attached to the drive shaft 27, and movement of the drive shaft 27 in the axial direction is restricted.

2 and 3, the driven roller 26 includes a support shaft 42 and a plurality of roll bodies 43 that are externally fitted to the support shaft 42 and are rotatable.
The support shaft 42 extends in parallel with the drive shaft 27 of the drive roller 25, and both ends thereof are supported by the housing 21 and the like.
For example, two roll bodies 43 are provided corresponding to the number of roll bodies 28 of the drive roller 25. The one roll body 43a and the other roll body 43b are respectively disposed in the middle portion of the support shaft 42, and are arranged at a predetermined interval in the axial direction of the support shaft 42. Each roll body 43 faces the corresponding roll body 28.

A spring 44 as an elastic member is placed between the support shaft 42 of the driven roller 26 and the housing 21, and the driven roller 26 is biased toward the drive roller 25 by the biasing force of the spring 44. . Thereby, each roll body 43 of the driven roller 26 and the corresponding roll body 28 of the driving roller 25 are pressed to form a nip N2.
The transport device 5 having the above configuration operates as follows during image formation. That is, when the paper P is sent out from the paper storage unit to the paper transport path L1, the registration roller pair 12 of the transport device 5 is stopped without being driven. On the other hand, in the loop forming roller pair 16, the drive shaft 27 is rotationally driven in the rotational direction R1, and each roll body 28 rotates integrally with the drive shaft 27 via the one-way clutch 30 or the like. Each roll body 43 of the driven roller 26 rotates with the rotation of.

  When the leading end of the paper P fed out of the paper storage unit reaches the nip N2 of the loop forming roller pair 16, the paper P is conveyed toward the registration roller pair 12 by the loop forming roller pair 16. As a result, the sheet P is received by the nip N1 of the pair of registration rollers 12 whose leading end is stopped, and a loop B is formed on the sheet P. At this time, with respect to the width direction W, the leading edge of the sheet P is in a state of being in contact with the nip N1 of the registration roller pair 12 and the oblique correction of the leading edge of the sheet P is achieved.

  When the loop B is formed on the paper P and the oblique correction is performed, the loop forming roller pair 16 stops driving and stops the conveyance of the paper P. Specifically, driving of the drive shaft 27 is stopped, and rotation of each roll body 28 of the driving roller 25 is stopped. Accordingly, the rotation of each roll body 43 of the driven roller 26 is also stopped. At this time, the one roll body 28 a and the other roll body 28 b of the drive roller 25 are connected via the joint 29, so that they stop at the same timing.

Thereafter, the registration roller pair 12 starts to be driven at a predetermined timing, and the timing at which the toner image formed on the photosensitive drum 6 reaches the transfer position T and the timing at which the paper P reaches the transfer position T are set. The paper P is transported so as to match.
Here, since each roll body 28 of the drive roller 25 of the loop forming roller pair 16 is connected to the drive shaft 27 via the one-way clutch 30, only the roll body 28 is rotationally driven in the rotational direction R1. At that time, the drive shaft 27 is not rotated, and each roll body 28 idles with respect to the drive shaft 27.

  Therefore, when the paper P is conveyed by the registration roller pair 12 and each roll body 28 is rotated by the paper P, the roll body 28 of the driving roller 25 is idled in the rotation direction R1. That is, the paper P conveyed by the registration roller pair 12 is smoothly conveyed without being prevented from being conveyed by the roll members 28 and 43 of the loop forming roller pair 16.

As described above, according to this embodiment, the roll bodies 28 of the driving roller 25 of the loop forming roller pair 16 are connected to each other via the joint 29 so as to be integrally rotatable with each other. Can be stopped.
As a result, when the driving of the loop forming roller pair 16 is stopped and the formation of the loop B on the paper P is completed, the timing of stopping the rotation of each roll body 28 is matched, and the paper P by each roll body 28 is matched. The feed amount can be matched. Therefore, the paper P is not twisted. As a result, it is possible to prevent the paper P from being wrinkled when the paper P is being conveyed by the registration roller pair 12.

Further, only one one-way clutch 30 having a high manufacturing cost may be provided, and the manufacturing cost can be reduced.
Furthermore, by forming the joint 29 in a cylindrical shape, the joint 29 can be configured with a simple shape, and the cost can be further reduced. In addition, the joint 29 is disposed between the adjacent roll bodies 28, and a portion of the paper P between the plurality of roll bodies 28 can be received by the joint 29.

Thereby, the bending of the paper P between the adjacent roll bodies 28 can be reduced. As a result, it is possible to more reliably prevent the paper P from being wrinkled.
The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims. For example, as shown in FIG. 6, with respect to the connection between the first member and the second member of the joint 29, the concave portion 35 is formed in a V-shaped groove, and the convex portion 36 and the corresponding concave portion 35 are formed with a width. A gap (backlash) between the convex portion 36 and the concave portion 35 may be narrowed by providing a spring 45 (biasing means) that biases so as to approach the direction W.

The spring 45 is formed of, for example, a coil spring wound around the drive shaft 27 of the drive roller, and one end is received by the drive shaft 27 and the other end is received by the other roll body 28b. The spring 45 is compressed in the width direction W to generate an elastic repulsive force. The ridge line of the convex portion 36 is formed in an arc shape, for example.
In this case, it is possible to prevent backlash in the circumferential direction between the one roll body 28a and the other roll body 28b, and the connection of the roll bodies 28 can be made stronger.

Moreover, as shown in FIG. 7, the ridgeline of the convex part 36 may be formed in a mountain shape. In this case, the inclination of the ridge line of the convex portion 36 with respect to the axis C of the joint 29 is made larger than the inclination of the ridge line of the concave portion 35 with respect to the axis line C.
Further, as shown in FIG. 8, an elastic member 46 may be provided in the paper conveyance path L <b> 1 between the registration roller pair 12 and the loop forming roller pair 16. Accordingly, when the registration roller pair 12 starts to be driven and the loop B of the paper P is relaxed, the relaxation speed of the loop B can be reduced by the engagement between the paper P and the elastic member 46. As a result, the generation of wrinkles on the paper P can be made more difficult to occur.

Further, the joint 29 may be formed of a single member. Further, each roll body 43 of the driven roller 26 of the loop forming roller pair 16 may be connected by a joint 29, and for example, the one-way clutch 30 may be interposed between one roll body 43a and the support shaft 42.
Furthermore, the present invention can be applied to a conveyance device provided in a sheet-through type document reading device.

1 is a longitudinal sectional view illustrating a schematic configuration of a copying machine as an image forming apparatus including a transport device according to an embodiment of the present invention. FIG. 2 is an enlarged view of the periphery of the photosensitive drum in FIG. 1. It is sectional drawing which follows the AA line of FIG. 2, and has shown the principal part of the loop formation roller pair. It is a perspective view of a drive roller. It is a disassembled perspective view of the principal part of a drive roller. It is an illustration figure which shows the principal part of another embodiment of this invention. It is an illustration figure which shows the principal part of another embodiment of this invention. It is an illustration sectional view showing the important section of another embodiment of this invention.

Explanation of symbols

5 Conveying Device 12 Registration Roller Pair 16 Loop Forming Roller Pair 25 Drive Roller (One Roll Forming Roller Pair)
27 Drive shaft (support shaft) of the drive roller of the loop forming roller pair
28 Roll body (of the driving roller of the loop forming roller pair) 29 Joint 30 One-way clutch B Loop P Paper

Claims (2)

A registration roller pair and a loop forming roller that is provided upstream of the registration roller pair, conveys the sheet toward the registration roller pair, and forms a loop on the sheet whose tip is received by the stopped registration roller pair. A conveying device having a pair,
At least one of the loop forming roller pairs is
A spindle,
A plurality of roll bodies surrounding the support shaft, arranged in a predetermined interval in the axial direction, and connected to each other so as to be integrally rotatable;
A one-way clutch that is interposed between the support shaft and any one of the plurality of roll bodies and rotates the roll body with the rotation of the support shaft only when the support shaft is rotated in one direction;
A transport apparatus comprising:   The transport apparatus according to claim 1, wherein adjacent roll bodies of the plurality of roll bodies are connected via a cylindrical joint surrounding the support shaft.

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