JPH078501Y2 - Paper transport device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is concentrically fixed to a drive roller that is rotationally driven and a driven shaft that is rotatably supported, and forms a pair with the drive roller to roll. A sheet conveying device that has a driven roller in contact with the driven roller and a pressing unit that presses the driven shaft so that the driven roller is in pressure contact with the driving roller, and holds and conveys the sheet between the driving roller and the driven roller. Regarding

[Conventional technology]

In a copying machine, a printer, a facsimile, a printing machine, or the like, in order to convey a document such as an original, recording paper, or printing paper,
It is well known in the art to use a paper transport device of the type described above.

FIG. 6 shows an example of a conventional sheet conveying device. In this apparatus, a drive shaft 1 and a driven shaft 2 extending parallel to each other are rotatably supported by a machine frame (not shown), and a drive roller 3 and a driven roller 4 are fitted and fixed to the shafts 1 and 2, respectively. . The driving roller 3 and the driven roller 4 make rolling contact with each other, and the driving shaft 1 is driven to rotate by a driving device (not shown). It is nipped and conveyed between the rollers 3 and 4. At this time, the driven roller 4 is pressed against the drive roller 3 by the pressing means so that a reliable conveying force is exerted on the paper.

As shown in FIG. 7, the conventional pressurizing means includes a pair of pressurizing pieces 5 and 5 which are fitted into the driven shaft 2 and are in sliding contact, and the pressurizing pieces 5 and 5.
It has a pair of arm members 6 and 6 that are pressed against. These arm members 6 and 6 are supported by a machine frame (not shown) via pins 7 and 7 so as to be rotatable in the arrow A direction. The ends of a tension spring 8 are locked to both arm members 6, 6, and the spring 8
As a result, the arm members 6, 6 press the pressing pieces 5, 5 against the driven shaft 2, so that the driven roller 4 is pressed against the driving roller 3.

[Problems to be solved by the device]

As described above, in the conventional pressing means, the pressing piece 5,
5 is in sliding contact with the driven shaft 2. Therefore, the pressure piece
A large frictional force acts between 5, 5 and the driven shaft 2. This frictional force increases as the force of the spring 8 is increased in order to increase the pressure contact force between the driven roller 4 and the driving roller 3, and the frictional force acts as a load for preventing the rotation of the driven roller 4. To do. When such a load is applied, when the driven roller 4 and the driving roller 3 come into direct contact with each other, the frictional force transmits the rotation of the driving roller 3 to the driven roller 4, and even if the roller 4 is driven to rotate,
Particularly when a wide paper is nipped and conveyed between these rollers 3 and 4, many driving rollers 3 come into contact with the driven roller 4 via the paper having a low friction coefficient, so that the driven roller 4 is It will slip on the paper. If such a slip becomes large, the sheet conveyance speed may fluctuate, and the sheet may be skewed.

An object of the present invention is to provide a paper transporting device that eliminates the above-mentioned conventional drawbacks.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention is a sheet conveying apparatus of the type described at the beginning, in which the pressing means has a pair of pressing units symmetrically arranged with respect to the center of the conveyed sheet in the width direction. The pressurizing unit presses the driven shaft while rollingly contacting the peripheral surface of the driven shaft at different positions in the circumferential direction, and the center axis of the pressurizing unit corresponds to the center axis of the driven shaft. At least two located in parallel
Individual pressure rollers, a common support member that rotatably supports these pressure rollers, a bearing that is assembled to the support members and that has a spherical inner surface, and a spherical inner surface of the bearing A support shaft having a spherical portion that is slidably fitted to the
The support shaft is fixed, and the pressure roller has an arm member pivotally supported in a direction in which the pressure roller is in pressure contact with or separated from the peripheral surface of the driven shaft. ,
There is provided a sheet transporting device, wherein the pressure roller of each pressure unit is connected by a biasing member that rotates and biases each arm member in a direction in which the pressure roller is pressed against the peripheral surface of the driven shaft.

〔Example〕

An embodiment of a sheet conveying device according to the present invention will be described below in detail with reference to the drawings.

In FIGS. 1 and 2, a drive shaft 1 and a driven shaft 2 extending parallel to each other are rotatably supported by a machine frame (not shown), and a drive roller 3 and a driven roller fitted to these shafts 1 and 2 are mounted. Reference numeral 4 is concentrically and integrally fixed to each of the shafts 1 and 2. A plurality of drive rollers 3 and a plurality of driven rollers 4 are provided, and these are paired with each other and are in rolling contact with each other.
The driving roller 3 is rotationally driven in the clockwise direction in FIG. 2 by a driving device (not shown), and the driven roller 4 is driven to rotate in the counterclockwise direction accordingly, and the paper P nipped by the rollers 3 and 4 is rotated. While being guided by the upper and lower guide plates 40, 41,
It is conveyed in the direction of arrow B. The driven rollers 4 and the driving rollers 3 are arranged symmetrically with respect to the center C of the paper P in the width direction, and are configured to exert a uniform conveying force on the paper P over the entire width direction thereof. . The driven roller 4 is preferably made of an elastic material such as rubber.

As described above, the illustrated sheet conveying device has the drive roller 3 which is rotationally driven, and is concentrically fixed to the driven shaft 2 which is rotatably supported, and forms a pair with the drive roller 3. The driven roller 4 is in rolling contact with the driven roller 4, and the paper P is sandwiched between the driving roller 3 and the driven roller 4 to be conveyed. The sheet conveying device further includes a pressing unit that presses the driven shaft 2 so that the driven roller 4 comes into pressure contact with the drive roller 3. The details are as follows.

The pressing means has a pair of pressing units 33 and 133 arranged line-symmetrically with respect to the center C in the width direction of the conveyed paper P as shown in FIG. In this example, since the pressure units 33 and 133 have the same configuration, one pressure unit
Only the structure and operation of 33 will be described. The other pressure unit 13
With respect to 3, the same components as those of the pressure unit 33 on one side are denoted by reference numerals obtained by adding 100 to the reference numerals attached to the unit 33, and description thereof will be omitted.

1 to 4, the pressing unit 33 includes at least two pressing units 33 that press the driven shaft 2 while rollingly contacting the peripheral surface of the driven shaft 2 at different positions in the circumferential direction. It has pressure rollers 12 and 13. In this example, two pressure rollers 12 and 13 are provided, and the center axis of each pressure roller 12 and 13 is positioned parallel to the center axis of the driven shaft 2. The pressure unit 33 has a common support member 14 that rotatably supports the pressure rollers 12 and 13. In this example, the two central shafts 10 and 11 have support members 14 and 13.
Are fitted and supported in the holes 15 and 16 of the
Each pressure roller 12 and 13 is rotatably supported. Two pressure rollers 12 and 13 are located with the support member 14 sandwiched therebetween, and by the stop rings 18 and 19 fitted in the annular grooves 50 and 17 of the central shafts 10 and 11, respectively. Is prevented from exiting.

Further, the pressure unit 33 is assembled to the support member 14, and has a bearing 22 having a spherical inner surface 21, and a spherical portion 24 fitted to the spherical inner surface 21 of the bearing 22 so as to be relatively slidable. The bearing 22 is fitted into the mounting hole 20 formed in the support member 14.

As shown in FIG. 5, the bearing 22 has two half-ring-shaped pieces 22.
a, 22b, which are assembled to match the spherical surface portion 24 of the support shaft 23, then the bearing 22 is fitted into the mounting hole 20 of the support member 14, and the retaining ring 26 is fitted into the groove portion 25 of the bearing 22. Thereby, by the ring 26 and the flange portion 27 of the bearing 22,
The bearing 22 can be assembled to the support member 14.

Further, the pressurizing unit 33 has an arm member 28 to which the support shaft 23 is fixed, and in this example, the support shaft 23 is fixed to the arm member 28 by a screw on the base end side of the support shaft 23. . The arm member 28 is rotatably supported by a base member 29 integrally fixed to the guide plate 40 via a pin 30. As described above, the arm member 28 includes the pressure rollers 12, 13
Is rotatably supported via a pin 30 so as to be pressed against the peripheral surface of the driven shaft 2 or rotatable in a direction away from the driven shaft 2 (a direction substantially perpendicular to the paper surface of FIG. 1).

One pressurizing unit 33 is configured as described above, and the other pressurizing unit 133 is configured similarly to the one pressurizing unit 33 as described above. At that time, each pressurizing unit
The end portions of a tension spring 31, which is an example of a biasing member, are locked to the hook portions 32 and 132 of the arm members 28 and 128 of the 33 and 133, and the hook portions 32 and 132 are pin 3 as can be seen from FIG.
It is a distance L away from the center of 0,130. Therefore, moments of substantially the same magnitude about the pins 30 and 130 act on the arm members 28 and 128, respectively. In this way, a tension spring 31 connecting the two arm members 28, 128 to each other is provided.
Is the pressure roller 12, 13, 112, 113 of each pressure unit 33, 133.
Each arm member in a direction in which is pressed against the peripheral surface of the driven shaft 2.
28 and 128 are urged to rotate. Therefore, each pressure roller 12, 13,
The rollers 112, 113 rotate according to the rotation of the driven shaft 2 while rollingly contacting the driven shaft 2, and pressurize the driven shaft 2. Due to this pressing action, the driven roller 4 is brought into pressure contact with the drive roller 3, the rotation of the drive roller 3 is transmitted to the driven roller 4, and a predetermined conveying force is exerted on the paper P nipped between them. it can.

At that time, the pressure rollers 12, 13, 112, 113 are not in sliding contact with the driven shaft 2 but in rolling contact therewith, and therefore the resistance force acting on the driven shaft 2, that is, the driven roller 4
The load given to can be significantly reduced. As a result, the driven roller 4 is reliably rotated by the rotational force transmitted from the drive roller 3 via the paper P, and slippage between the driven roller 4 and the paper P can be prevented. Therefore, it is possible to effectively suppress the skew of the paper.

In order to reduce the load on the driven shaft 2 more reliably, the pressure rollers 12, 13, 112, 113 are each formed of a ball bearing in the illustrated example.

Further, the pressure rollers 12, 13 and 112, 113 of the pressure unit 33, 133 are
Are pressed against the driven shaft 2 at different points in the circumferential direction of the driven shaft 2, so that each pressure roller can be brought into rolling contact with the driven shaft 2 in a stable state and pressed against the driven shaft 2. Therefore, a stable pressure can always be applied to the paper P, and the skew of the paper P can be suppressed more effectively.

Further, the support member 14 that supports the pressure rollers 12 and 13 has a bearing 22.
And is supported by an arm member 28 via a support shaft 23 having a spherical surface portion 24 fitted to the spherical inner surface 21, and the support member 14 is supported by the support shaft 23 and the support arm 28 together with the pressure rollers 12, 13. On the other hand, it is possible to relatively freely rotate three-dimensionally around the center point 34 of the spherical surface portion 24. That is,
The support member 14 that supports the pressure rollers 12 and 13 is supported by the arm member 28 via the support shaft 23 so as to be swingable around the center point 34. Moreover, arm members
28 is supported by the base member 29 so as to be freely rotatable around the pin 30 as described above.

With such a configuration, even if the assembled state of the driven shaft, that is, the relative position between the base member 29 and the driven shaft 2 is slightly deviated from the predetermined state due to variations in component accuracy or the like, the arm member 28 is responsive to the deviation. Rotates about a pin 30, and the support member 14 and the pressure rollers 12 and 13 rotate about a spherical portion center point 34 of the support shaft 23 relative to the support shaft 23 and the arm member 28. Therefore, the central axes of the pressure rollers 12 and 13 and the central axis of the driven shaft 2 are always maintained in parallel with each other, and the entire widths of the pressure rollers 12 and 13 are always in contact with the peripheral surface of the driven shaft 2 so as to be in close contact with each other. . In this way, the driven shaft 2 can be pressed in a stable state by the pressure rollers 12 and 13, and the paper P
The uniform pressure can be applied to the sheet, and the skew of the sheet can be more reliably prevented.

FIG. 4 explains the situation at this time. That is, as described above, the arm member 28 can be tilted about the pin 30 as shown in FIG. 4 due to the deviation of the relative position between the base member 29 and the driven shaft 2, and at this time, the support member 14 rotates around the center point 34. Is rotated so as to compensate the inclination of the arm member 28, and the pressure rollers 12 and 13 come into contact with the peripheral surface of the driven shaft 2 in a close contact state.

The above-described operation can be obtained in the same manner on the side of the other unit 133.

Also, the pressure rollers 12, 13 and 112, 1 of each pressure unit 33, 133 are
13 presses the driven shaft 2 at a position symmetrical with respect to the widthwise center C of the paper P, and the pressure rollers 12, 13 and 112, 113 are pressed against the driven shaft 2 by the urging action of the tension spring 31. Since almost equal pressure is exerted on the sheet P, even pressure is exerted on the sheet P over its entire width, and the skew is prevented more reliably.

In the embodiment described above, the pressure roller is pressed against the driven shaft at two different positions in the circumferential direction. However, the pressure roller is pressed at three or more positions in the circumferential direction. It is also possible to provide three or more pressure rollers in the circumferential direction of the driven shaft.

Further, in the above-described embodiment, the driven roller is integrally fixed to the driven shaft, but the inner diameter of the driven roller is formed slightly larger than the outer diameter of the driven shaft, and the driven roller is loosely fitted to the driven shaft.
The present invention is also applied to a sheet conveying device in which the driven roller is concentrically fixed to the driven shaft by rotating the driven shaft by the frictional force acting on the inner peripheral surface of the driven roller and the outer peripheral surface of the driven shaft when the driven roller rotates. Can be applied.

[Effect of device]

According to the present invention, since the driven shaft is pressed by the pressure roller that comes into rolling contact with the driven shaft, the load applied to the driven roller can be reduced and the skew of the paper can be suppressed. In addition, the pressure roller of each pressure unit arranged symmetrically with respect to the widthwise center of the sheet acts on the driven shaft by the urging action of the urging member that connects the arm member of each pressure unit. Since a substantially equal pressure is exerted, a uniform pressure is exerted on the sheet over its entire width, and the skew can be more reliably prevented.

Further, since the plurality of pressure rollers of each pressure unit are in pressure contact with the driven shaft at different positions in the circumferential direction of the driven shaft, each pressure roller is in pressure contact with the driven shaft in an extremely stable state. Therefore, a stable pressure can always be applied to the paper, and the skew of the paper can be suppressed more effectively.

In addition, a bearing having a spherical inner surface is assembled to the support member that supports the pressure roller of each pressure unit, and the spherical portion of the support shaft is fitted into the spherical inner surface so as to be relatively slidable. ,
In addition, the arm member to which the support shaft is fixed is pivotally supported so that the pressure roller can rotate in a direction in which the pressure roller is in pressure contact with or away from the peripheral surface of the driven shaft. Even if the state is slightly deviated from the predetermined state, the arm member is rotated according to the deviated state, and the support member and the pressure roller are relatively centered on the spherical portion of the support shaft with respect to the support shaft and the arm member. Rotate around a point. As a result, the central axis of the pressure roller and the central axis of the driven shaft are always maintained in parallel with each other, and the entire width of the pressure roller is always in contact with the peripheral surface of the driven shaft so as to be in close contact therewith. Therefore, the driven shaft can be pressed in a more stable state by the pressure roller, uniform pressure is applied to the paper, and skew of the paper can be more reliably prevented.

[Brief description of drawings]

FIG. 1 is a plan view of a sheet conveying apparatus according to an embodiment of the present invention, in which a guide plate is omitted, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is each pressure roller. FIG. 4 is a plan view showing the supporting shaft and the supporting portion of the arm member in a sectional view, and FIG. 4 is a view corresponding to a sectional view taken along line IV-IV of FIG. 3, showing a state when the arm member is inclined. 5 and 5 are schematic views showing the bearing pieces separated from each other, FIG. 6 is a perspective view of a conventional sheet conveying apparatus, and FIG. 7 is a sectional partial view thereof. 2 ... driven shaft, 3 ... driving roller 4 ... driven roller, 12,112,13,113 ... pressing roller 14,114 ... supporting member, 21 ... inner surface 22,122 ... bearing, 23,123 ... supporting shaft 24 ... spherical part, 28,128 ... arm member 33,133 ... pressurizing Unit C ... Center, P ... Paper

Claims (1)

[Scope of utility model registration request] 1. A driven roller which is rotationally driven, a driven roller which is concentrically fixed to a driven shaft which is rotatably supported, and which makes rolling contact with the driven roller, and the driven roller is a driven roller. In a sheet conveying device that has a pressing unit that presses a driven shaft so as to be in pressure contact, and that conveys a sheet by sandwiching the sheet between a driving roller and a driven roller, A pair of pressurizing units are arranged symmetrically with respect to the center in the width direction, and each pressurizing unit is in rolling contact with the peripheral surface of the driven shaft at different positions in the peripheral direction. , At least two pressure rollers which press the driven shaft and whose central axis is positioned parallel to the central axis of the driven shaft, and a common support member which rotatably supports these pressing rollers, Assembled to the support member The pressure roller comprises a bearing having a spherical inner surface, a support shaft having a spherical portion slidably fitted to the spherical inner surface of the bearing, and the support shaft being fixed. Pressed against the peripheral surface of the driven shaft,
Or an arm member that is rotatably supported so as to be separated from each other, and these arm members are arranged so that the pressure roller of each pressure unit is in pressure contact with the peripheral surface of the driven shaft. A sheet conveying device, wherein the sheet conveying device is connected by an urging member for urging the sheet.