JPH11218153A - Torque limiter, sheet feeding device and image processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque limiter capable of changing the transmission torque value, and provide a sheet feeding device and an image forming device using the torque limiter. SOLUTION: In a torque limiter 37 transmitting a fixed range of torque by hysteresis torque generated by the relative rotation of a permanent magnet 40 and a magnetic substance 44 provided opposedly to the permanent magnet 40, the permanent magnet 40 has a plurality of magnet parts 40a-40c with different magnetic force, and a moving means is provided to change the relative position of the magnetic parts 40a-40c and magnetic substance 44 so that the magnetic substance 44 is selectively opposed to the magnet parts 40a-40c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter for transmitting a predetermined range of torque, a sheet feeding device using the same, and an image processing device.

[0002]

2. Description of the Related Art A torque limiter using a hysteresis torque is used in a sheet feeding device such as a copying machine, a printer, and a facsimile.

FIGS. 7 and 8 show examples of a sheet feeding apparatus. In the figure, a retard roller 100 is pressed against a feed roller 101 at a predetermined pressure, and a sheet bundle sent by a pickup roller (not shown) is sandwiched in a nip portion. The retard roller 100 has
A constant torque T is always applied in the direction of returning the seat 103 via the torque limiter 102. Here, as shown in FIG. 7, when two or more sheets are sandwiched between the feed roller 101 and the retard roller 100, the second and subsequent sheets are separated from the first sheet, and Is returned in the opposite direction.

However, when the feed roller 101 and the retard roller 100 are in direct contact with each other or when only one sheet is sandwiched between the feed roller 101 and the retard roller 100 as shown in FIG. Follow the direction of sending. Therefore, in order to reliably feed the sheets 103 one by one, the sheet conveying force generated by the reverse rotation torque T applied to the retard roller 100 by the torque limiter 102 is larger than the frictional force between the sheets, but the feed roller 101 Must be smaller than the sheet conveyance force. And the torque limiter
Torque T applied to retard roller 100 by 102
And the pressing force for pressing the retard roller 100 against the feed roller 101 depends on the type of sheet to be fed, environmental conditions,
Alternatively, the appropriate value slightly varies depending on the material of the rollers 100 and 101.

As an example of the invention of the torque limiter described above, there is Japanese Patent Application Laid-Open No. Hei 6-221341. According to the present invention, as shown in FIG.
One rotating body 104 has a cylindrical permanent magnet 105 fixed thereto, and the other rotating body 10 has
In FIG. 6, a cylindrical semi-hard magnetic body 107 opposed to the permanent magnet 105 at a certain interval is fixed, so that both rotating bodies are caused by a hysteresis torque generated between the permanent magnet 105 and the semi-hard magnetic body 107. It was common to have a structure that transmits a constant torque between them.

[0006]

In the conventional torque limiter 102 as described above, a permanent magnet 105 and a semi-hard magnetic material are used.
Since the torque of the torque limiter is determined by the distance from the motor 107, a constant idling torque value is obtained. Therefore, although it is advantageous for the life of the feed roller 101 such as an OHT sheet depending on the type of the sheet, when the idling torque value must be set large due to the large frictional resistance between the sheets, or when the special sheet is used. In the case of, the frictional resistance between the sheets is small due to the additives contained in the special sheet member, but the life of the feed roller 101 is hard to last, so the idling torque value must be set small. It was necessary to prepare a torque limiter with an idling torque value suitable for the member.

Further, a torque limiter having a different set torque is required depending on the type of the sheet member to be used or due to a difference in the use environment and the like, so that the assemblability at the time of assembling is poor and the cost is increased. Had become.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a torque limiter capable of changing a transmission torque value, a sheet feeding apparatus and an image forming apparatus using the same. Is provided.

[0009]

A typical configuration according to the present invention for achieving the above object is to rotate a permanent magnet and a magnetic body provided opposite to the permanent magnet relatively. In a torque limiter that transmits a predetermined range of torque by the generated hysteresis torque, the permanent magnet has a plurality of magnets having different magnetic forces, and the magnets and the magnets are arranged so that the magnetic body selectively faces the magnets. It has a moving means for changing a relative position with respect to a body.

In the above configuration, when the relative position between the magnet portion and the magnetic material is changed by the moving means, the magnetic force of the permanent magnet facing the magnetic material changes, and the generated hysteresis torque changes. Thereby, the transmission torque can be changed.

Therefore, by using the torque limiter having the above-described structure in a sheet feeding device, it becomes possible to separate sheets by transmitting appropriate torque to various sheets, and to feed sheets without double feeding. Image processing can be performed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a torque limiter, a sheet feeding device, and an image processing device to which the present invention is applied will now be described with reference to the drawings.

[First Embodiment] A torque limiter and the like according to a first embodiment will be specifically described with reference to FIGS. FIG. 1 shows a torque limiter.
(a) is an external view, and (b) is an explanatory sectional view. 2 and 3 show a state in which the hysteresis torque of the torque limiter is set so as to be changed. FIG. 2A is an external view, and FIG. FIG. 4 is an overall schematic diagram of a copying machine which is an example of an image processing apparatus.
FIG. 6 is an overall schematic diagram of the sheet feeding device, and FIG. 6 is an explanatory diagram of a drive transmission structure to sheet feeding means.

Here, as the order of the description, first, the overall configuration of the copier as the image processing apparatus will be described, and then the sheet feeding apparatus and the torque limiter will be described.

{Overall Configuration of Image Processing Apparatus} As shown in FIG. 4, the image processing apparatus according to the present embodiment has a feeding deck 2 in which a large number of sheets S are stacked and stored on one side of an image processing apparatus main body 1. And a plurality of feed cassettes 3 in which a predetermined amount of sheets S are stacked and stored in the lower portion of the image processing apparatus main body 1.
4 is provided.

The feed deck 2 serving as a feed unit for feeding the sheets S and the installation sites of the respective feed cassettes 3 and 4 are provided in the sheet feeding devices 5, 6 and 7 of the retard separation system, respectively. Is provided. The feeding device will be described later in detail.

When the sheets S in the feeding deck 2 and the feeding cassettes 3 and 4 are fed by the respective sheet feeding devices 5, 6 and 7, first, the sheets S are fed to the registration roller pair 8 which has stopped rotating. Then, the skew state is corrected here.

Next, based on the information optically read by the reading means 21, a pair of registration rollers which rotate at a timing with a latent image formed on the photosensitive drum 9 constituting an image forming unit as a processing means. 8, the photosensitive drum 9
, And the toner image on the photosensitive drum 9 is transferred here.

Thereafter, the sheet S is sent to the fixing device 12 by the transport belt 11, and a fixing process for fixing the transferred toner image on the sheet surface is performed.

The image processing apparatus is provided with a duplex copying mode for performing duplex copying on the sheet S and a multiplex copying mode for performing multiple copying. In the normal copying mode (single-sided copying mode), the sheet S after the fixing process is used. Is discharged onto a discharge tray 15 outside the apparatus by an inner discharge roller pair 13 and an outer discharge roller 14.

In the case of the double-sided copy mode and the multiple copy mode, the pair of inner discharge rollers 13 or the pair of switchback rollers 16 temporarily places the sheet on the intermediate tray 19 via the re-feeding path 17 and the double-sided conveying path 18. It is loaded and stored.

Then, the sheet S stored on the intermediate tray 19 is again conveyed to the registration roller pair 8 for image formation by the re-feeding device 20, and thereafter discharged out of the apparatus through the same process as for one-sided copying. You.

{Sheet Feeding Apparatus} Next, the sheet feeding apparatuses 5, 6, and 7 will be described. Here, the configuration of the feeding device 5 will be described as an example, but it goes without saying that the other feeding devices 6 and 7 may have the same configuration as needed.

The sheet feeder 5 sequentially separates and feeds the sheets one by one toward the above-described image forming section. As shown in FIG. 5, a plurality of sheets S are stacked and stored. Roller 22 that feeds the uppermost sheet S one by one from the feeding deck 2, and a separation roller that conveys the sheet S fed from the feeding deck 2 by the pickup roller 22 into the image processing apparatus main body. Vs. 23,
A registration roller pair 8 for transporting the separated sheet S to the downstream side is provided.

The separation roller pair 23 includes a feed roller 24 that rotates in the direction of conveying the sheet, and a retard roller 25 that rotates in the direction of returning the sheet by contacting the feed roller 24 with a predetermined pressure. Pickup roller 22,
Feed roller 24 and retard roller 25 of separation roller pair 23
The rotational drive from a driving source (not shown) installed in the image processing apparatus main body 1 is transmitted through the power transmission mechanism shown in FIG. That is, the rotational power of the drive source is
Further, the power is transmitted to a roller shaft 28 of the feed roller 24 via an electromagnetic clutch 27.

The rotational power transmitted to the roller shaft 28 of the feed roller 24 is transmitted 1: 1 to the pickup roller shaft 32 of the pickup roller 22 via the pulley 29, the timing belt 30, and the pulley 31. Further, the rotational power from the roller shaft 28 is supplied to the pulley 33, the timing belt 34, and the pulley 35.
And transmitted to a relay shaft 36 of the retard roller 25 via a torque limiter 37 and a coupling 38 described later.

When voltage is applied to the electromagnetic clutch 27, the rotational power of the drive source is transmitted to the roller shaft 28, and the feed roller
Reference numeral 24 rotates in the direction in which the sheet is conveyed (the direction of arrow A).
Further, the pickup roller 22 also rotates via the timing belt 30 in the direction for transporting the sheet (the direction of arrow C). The rotation of the roller shaft 28 is transmitted to the relay shaft 36 via the timing belt 34. Accordingly, the retard roller 25 rotates in a direction (arrow B direction) to return the sheet S in synchronization with the rotation of the feed roller 24. But retard roller 25
When the torque greater than the set value is applied because the rotational power is transmitted through the torque limiter 37, the retard roller 25
Is idle, and is driven to rotate by the feed roller 24.

The sheet fed by the pickup roller 22 to the nip portion of the separation roller pair 23 as described above
When there is only one sheet, the retard roller 25 becomes idle,
The sheet is conveyed downstream by rotating following the feed roller 24. When a plurality of sheets fed by the pickup roller 22 enter, the retard roller 25 rotates in the direction of arrow B, so that the sheets other than the uppermost layer are returned to the retard roller 25 and Only the upper layer is separated and transported downstream.

{Torque Limiter} Next, the structure of the torque limiter 37 will be described with reference to FIGS. As shown in FIG. 1 (b), the torque limiter 37 is a cylindrical member having magnetic forces Ba, Bb, and Bc (not shown), and magnet portions 40a, 40b, and 40c having different magnetic forces connected via a plate member 40d. A drive-side rotating body 41 to which a permanent magnet 40 is fixed,
The driven-side rotator 42 is configured to be relatively rotatable, the driven-side rotator 42 is formed with a hole 42a for penetrating the relay shaft, and the other end is formed with a bearing hole 43a at the center. 43 is fixed to the driven-side rotating body 42. A cylindrical magnetic body 44 that can move in the axial direction is provided on the inner peripheral surface of the driven side rotating body 42, and the magnetic body 44 is provided on a pin 45 fixed to the outer circumference and the driven side rotating body 42. The driven groove 42 rotates integrally with the driven-side rotator 42. A compression spring 47 having one end in contact with the driven-side rotating body 42 and the other end in contact with the cylindrical magnetic body 44 is arranged on the inner peripheral surface of the driven-side rotating body 42. The magnetic body 44 is urged by a compression spring 47 rightward in FIG. The drive-side rotating body 41 and the relay shaft 36
Are connected by a pin 48 and a notch 41a, and are connected to a drive mechanism.

In FIG. 1A, locking grooves 46a and 46b are provided in a groove 46 formed in the driven-side rotating body 42.
The axial width of the cylindrical magnetic body 44 has substantially the same length as the axial width of each of the magnet portions 40a, 40b, and 40c having different magnetic forces of the cylindrical permanent magnet 40.

The cylindrical magnetic body 44 can be moved in the axial direction of the driven-side rotator 42 by means of the pin 45 and the groove 46, as shown in FIG.
In the position shown in FIG. 3, the compression magnet 47 is biased by the compression spring 47 and is located at a position facing the magnet portion 40a of the cylindrical permanent magnet 40. In this case, the magnetic force generated by the cylindrical permanent magnet 40 is Ba, a corresponding hysteresis torque Ta is generated, and the drive from the drive mechanism is transmitted to the retard roller 25 via the coupling 38.

In FIG. 2, the cylindrical magnetic body 44 is a compression spring.
The pin 45 is moved against the urging force of the pin 47 and is engaged with the engaging groove 46a so as to be located at a position facing the magnet portion 40b of the cylindrical permanent magnet 40. In this case, the magnetic force generated by the cylindrical permanent magnet 40 is Ba, and a corresponding hysteresis torque Tb is generated. Similarly, in FIG. 3, the pin 45 is locked in the locking groove 46b, and a hysteresis torque Tc corresponding to the magnetic force Bc is generated.

The relationship between the magnetic force generated by the cylindrical permanent magnet 40 and the hysteresis torque generated thereby is such that the larger the magnetic force, the larger the hysteresis torque. Therefore,
The magnetic force generated by the magnet portions 40a, 40b, 40c is Ba, respectively.
>Bb> Bc, the hysteresis torque is Ta> T
b> Tc.

Therefore, when the set torque value is changed to feed the special sheet, the pin 45 is engaged with the locking groove 46a,
Set without locking to any of 46b. As a result, the sheet S does not double feed because the hysteresis torque that starts to slip is increased (the transmission torque is increased).

On the other hand, when it is difficult to double feed due to the additive contained in the sheet, but it is difficult to extend the life of the roller and it is necessary to set a small torque, the pin 45 is engaged with the locking groove 46.
Set to b. As a result, the hysteresis torque that starts to slip is reduced (the transmission torque is reduced), and the life of the roller is extended.

Thus, the torque of the torque limiter 37 can be changed only by moving the cylindrical magnetic body 44. Further, the movement of the cylindrical magnetic body 44 can be performed without disassembling the torque limiter 37, and can be easily performed even when the torque limiter 37 is incorporated in the machine main body.

Incidentally, the cylindrical permanent magnet 40 is made of a ferrite magnet or a rare earth magnet (both include a sintered magnet and a resin magnet).
However, it is desirable to use a rare earth magnet from the viewpoint of reducing the size of the torque limiter and increasing the torque. Rare earth magnets include Nd-Fe-B magnets, Sm-Fe-N magnets, and Sm-Co magnets.

The cylindrical magnetic body 44 is made of a metal material having a residual magnetic flux density and a certain degree of coercive force (10 to 10,000 e) and a square hysteresis. From the viewpoint, Fe-Co alloy,
It is preferable to use a Fe-Cr-Co alloy or the like.

Although the permanent magnet 40 is arranged in the magnetic body 44 in the present embodiment, the magnetic body may be arranged in the permanent magnet.

[Other Embodiments] In the above-described embodiment, an example in which the magnitude of the torque can be adjusted to three types has been described. However, the present invention is not limited to this.

In the above-described embodiment, the plurality of magnet portions 40a, 40b, and 40c having different magnetic forces are connected to the plate member 40d.
Although the cylindrical permanent magnets 40 are connected through the intermediary, it is apparent that the same effect can be obtained by magnetizing a single magnet with a different magnetic force for each fixed width.

In the above-described embodiment, the magnetic body 44 is moved with respect to the magnet portions 40a, 40b, 40c.
The magnetic body 44 and the magnet units 40a, 40b, 40c may be moved relatively, and the magnet units 40a, 40b, 40c may be moved.

Further, in the above-described embodiment, an example in which the torque limiter is used in the sheet feeding device has been described. However, the torque limiter is preferably used in a device other than the sheet feeding device for changing and transmitting the rotational torque. Can be.

In the above-described embodiment, the case where the sheet feeding device feeds the recording sheet of the copying machine has been described.
This sheet feeding apparatus can also be suitably used for an image reading apparatus or the like that separates and feeds a plurality of set originals one by one and reads the written information of the originals. Therefore, the image processing apparatus may be not only an image forming apparatus such as a copying machine or a printer but also an image reading apparatus such as a scanner.

[0045]

The present invention is constructed as described above.
When the magnetic body is moved by the moving means, the magnetic force of the permanent magnet facing the magnetic body changes, and the generated hysteresis torque changes, so that the transmission torque can be easily changed.

Therefore, by using the torque limiter having the above-described structure in the sheet feeding device, it becomes possible to separate the sheets by transmitting appropriate torque to various sheets, and to feed the sheets without double feeding. Image processing can be performed.

[Brief description of the drawings]

1A and 1B show a torque limiter, wherein FIG. 1A is an external view and FIG. 1B is an explanatory sectional view.

FIGS. 2A and 2B show a state in which the hysteresis torque of the torque limiter is set to be changed, wherein FIG. 2A is an external view and FIG.

FIGS. 3A and 3B show a state in which the hysteresis torque of the torque limiter is set to be changed, wherein FIG. 3A is an external view and FIG.

FIG. 4 is an overall schematic explanatory diagram of a copying machine which is an example of an image processing apparatus.

FIG. 5 is an overall schematic diagram of a sheet feeding device.

FIG. 6 is an explanatory diagram of a drive transmission configuration to a sheet feeding unit.

FIG. 7 is a diagram illustrating a state in which a plurality of sheets are separated and fed by a feed roller and a retard roller.

FIG. 8 is an explanatory diagram illustrating a state in which one sheet is fed by a feed roller and a retard roller.

FIG. 9 is an explanatory cross-sectional view of a configuration of a torque limiter according to a conventional technique.

[Explanation of symbols]

 S: Sheet 1: Image processing apparatus main body 2: Feeding deck 3, 4, Feeding cassette 5, 6, 7 ... Sheet feeding device 8: Registration roller pair 9: Photoconductor drum 10: Transfer charger 11: Conveying belt 12 ... fixing device 13 ... inner discharge roller pair 14 ... outer discharge roller 15 ... discharge tray 16 ... switchback roller pair 17 ... re-feed path 18 ... double-sided conveyance path 19 ... intermediate tray 20 ... re-feed device 21 ... reading means 22 ... pickup roller 23 ... separation roller pair 24 ... feed roller 25 ... retard roller 26 ... drive belt 27 ... electromagnetic clutch 28 ... roller shaft 29 ... pulley 30 ... timing belt 31 ... pulley 32 ... pickup roller shaft 33 ... pulley 34 ... timing Belt 35 ... Pulley 36 ... Relay shaft 37 ... Torque limiter 38 ... Coupling 39 ... Roller shaft 40 ... Cylindrical permanent magnets 40a, 40b, 40c ... Magnet part 40d ... Plate member 4 1 ... drive side rotating body 41a ... notch 42 ... driven side rotating body 42a ... hole 43 ... lid 43a ... bearing hole 44 ... cylindrical magnetic body 45 ... pin 46 ... groove 46a, 46b ... locking groove 47 ... compression Spring 48… pin

Claims (7)

[Claims] 1. A torque limiter for transmitting a predetermined range of torque by a hysteresis torque generated by a relative rotation of a permanent magnet and a magnetic body provided opposite to the permanent magnet, wherein the permanent magnets have different magnetic forces. And a moving unit for changing a relative position between the magnet unit and the magnetic body so that the magnetic body selectively faces the magnet unit. . 2. A torque limiter for transmitting a predetermined range of torque by hysteresis torque, comprising: a permanent magnet having a rotatable cylindrical shape and a plurality of magnet portions having different magnetic forces in a rotation axis direction; A cylindrical magnetic body rotatable about the same central axis as the center, and facing the permanent magnet with a predetermined gap; and selectively selecting the magnetic body with each magnet part of the permanent magnet. And a moving means for moving in the direction of the rotation axis so as to be able to face each other. 3. A method according to claim 1, wherein the predetermined gap is provided between one of the permanent magnet and the magnetic body, and the other is disposed between the inner peripheral surface of one cylindrical shape and the outer peripheral surface of the other cylindrical shape. 3. The torque limiter according to claim 2, wherein: 4. The permanent magnet and the magnetic body are provided so as to be relatively slidable in a rotation axis direction, and the moving means selectively slides the permanent magnet and the magnetic body relative to each other. 3. The torque limiter according to claim 1, wherein a magnet portion and a magnetic body are opposed to each other. 5. The torque according to claim 4, wherein the moving means has a locking portion for restricting the movement in a state where the magnet portion and the magnetic body are selectively opposed to each other. limiter. 6. A sheet feeding device for separating and feeding sheets one by one, comprising: a feeding rotator that rotates in a sheet feeding direction; and a direction in which the sheet is pressed against the feeding rotator and the sheet is returned. A sheet feeder, comprising: a retard rotator that rotates to the rotator; and transmitting torque to the retard rotator via the torque limiter according to any one of claims 1 to 5. apparatus. 7. An image processing apparatus for performing image processing by feeding a sheet, wherein the image processing unit performs image processing on the sheet fed by the sheet feeding apparatus. An image processing apparatus, comprising: