JP2002182449A - Image carrier driving device and speed increasing/ decreasing device for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image carrier driving device by which a high-quality image is obtained by reducing the density irregularity of an output image and the deviation of image position. SOLUTION: This image carrier driving device is used for a tandem type image forming device. The device is equipped with a plurality of image carriers 11, a 1st frictional wheel 21 coupled with the output shaft 12 of each image carrier 11, a 2nd frictional wheel 22 disposed between the adjacent wheels 21 and coming into contact with the outer peripheral surface of the wheel 21, and a wound and laid transmission element 13 transmitting motive power from a driving shaft 16 to the wheel 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image carrier driving apparatus for an image forming apparatus used in a tandem type image forming apparatus, and an increase / decrease speed increase / deceleration suitably used for the image carrier driving apparatus. Speed device.

[0002]

2. Description of the Related Art In a conventionally known image forming apparatus such as a printer and a copying machine, a driving element for transmitting a driving force to an image carrier such as a photoreceptor for holding an image or an intermediate transfer in an image forming process is particularly used. , Gears and toothed belts have been used. Also, in order to drive with higher accuracy,
A DD system for directly driving a driving source and an image carrier has also been used in some high-end machines.

In the prior art using a gear for transmitting the driving force to the image carrier, the meshing accuracy of the gear appears as a transmission error. In addition, gears usually used are often made of resin from the viewpoint of mass productivity and cost, and there is a limit to the accuracy obtained by molding.

Further, in order to obtain high transmission accuracy, it is necessary to increase the meshing ratio of the gears. To do so, it is necessary to increase the number of teeth of the gears. In addition, it becomes more difficult to secure the accuracy, and it becomes difficult to secure the strength for receiving the transmission force.

[0005] Further, the backlash peculiar to the gear cannot be reduced sufficiently in principle. Therefore, when the driven gear is vibrated by meshing, only the backlash play is easily moved. For this reason, in the case of a configuration in which an image carrier such as a photoconductor is connected to and driven by the driven gear, periodic unevenness in density is generated in an output image due to only a small excitation force generated by meshing vibration.

In the case where the driving force is transmitted by using a toothed belt, the meshing vibration that occurs can be somewhat reduced as compared with a gear, but a fundamentally periodic meshing vibration is generated, and a rubber member that is rich in flexibility. Is used, the vibration amplitude related to the transmission force is increased, the total transmission accuracy is not much different from that of the gear, and the disadvantage that periodic density unevenness occurs in the output image cannot be solved.

By the way, as a driving means for transmitting a rotational force, generally, a hand transmitting means such as a gear, a belt or a chain is widely used. In addition to these, transmission mechanisms using friction wheels have been used for some time. The transmission mechanism using the friction wheel has many advantages when the mechanism is simple, low noise, no backlash and the like, high transmission rigidity, and low price, but it has the following problems. (1) Friction wheels, which are transmission elements, are in line contact with each other. To transmit a large amount of force, a large contact pressure proportional to the transmission force is required for the friction wheel and the shaft supporting the friction wheel. A complicated mechanism is required. (2) Although it is structurally easy to construct a simple one-stage speed reducer, if a larger speed reduction ratio (or speed increase ratio) is to be obtained and a plurality of speed reductions (speed increase) are to be performed. ,
The structure becomes complicated.

In the case of a flat belt, a V-belt or the like having the same frictional transmission, to transmit a larger force, a material having a higher rigidity suitable for the transmission load is required, but at the same time, the deformation of the belt due to bending must be large. And generally it is difficult to achieve both.

Further, since a tension corresponding to the transmission load is required, and the belt is inevitably reduced in tension due to stress relaxation, in order to perform stable transmission, an automatic tension correction device is used or an extra tension is required. It is necessary to design with. An automatic tension compensator is expensive, and a design that allows for a reduction in tension hinders compactness.

[0010] In the meshing transmission of gears, toothed belts, chains, and the like, as described above, large noise, vibration, and backlash occur. Some mechanisms have problems such as the need for lubrication.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and has as its object to improve the structure of an image carrier driving device used in an image forming apparatus. An object of the present invention is to provide an image carrier driving device capable of reducing a density unevenness and an image position shift of an output image and obtaining a high-quality image.

Another object of the present invention is to provide an acceleration / deceleration device having low noise, low vibration, and high transmission rigidity.

Another object of the present invention is to provide a high-efficiency accelerating / decelerating device having a small loss at a low load because an axial load proportional to a load is generated.

Still another object of the present invention is to provide an inexpensive and stable device.
An object of the present invention is to provide a maintenance-free speed increasing / decelerating device.

Still another object of the present invention is to provide an acceleration / deceleration device having a plurality of output shafts having the above-mentioned contents.

Still another object of the present invention is to provide an acceleration / deceleration device having a plurality of output shafts having different rotation speeds.

[0017]

According to the present invention, there is provided an image carrier driving apparatus used in a tandem type image forming apparatus in which a plurality of image carriers are arranged in parallel.
A first friction wheel connected to the output shaft of each image bearing member, and a second friction wheel disposed between the adjacent first friction wheels and in contact with the outer peripheral surface of each first friction wheel. And a winding transmission element for transmitting power from a drive shaft to the second friction wheel, whereby the object is achieved.

In one embodiment, a pressure roller is provided to increase the tension of the wrapping element, and presses the second friction wheel against the contact surface of the first friction wheel.

In one embodiment, a flywheel is provided on a rotating shaft of the second friction wheel.

In one embodiment, the outer diameter of the second friction wheel is set to be larger than the shortest distance between the outer peripheral surfaces of the adjacent first friction wheels.

According to the present invention, there is provided an acceleration / deceleration apparatus comprising: a first friction wheel supported by a shaft; a third friction wheel or holding roller disposed at a distance from the first friction wheel; 3 between the friction wheels, or between the first friction wheel and the holding roller, and an outer diameter larger than the shortest distance between the outer peripheral surfaces of both friction wheels or between the first friction wheel and the outer peripheral surface of the holding roller. And a winding transmission element for transmitting a rotational force from a drive shaft to the second friction wheel, whereby the second friction wheel causes the first or second friction wheel to rotate. The frictional wheel 2 is brought into pressure contact with the peripheral surface of the friction wheel 2, thereby achieving the above object.

In one embodiment, the rotation shafts of the first friction wheel and the third friction wheel function as output shafts, and the rotation speeds of the respective output shafts are set to be different from each other.

In one embodiment, one of the first friction wheel and the second friction wheel is made of a magnetic material, and a magnet is attached to the other friction wheel, and a magnetic force is applied between the first and second friction wheels. The contact pressure has been increased.

[0024]

Preferred embodiments of the present invention will be described below. (Embodiment 1 of Image Carrier Driving Device) A photosensitive drum driving device 10 as an image carrier driving device of the present invention is used for an image forming apparatus such as a printer or a copying machine, and is shown in FIG. As described above, the tandem type printer continuously prints each color of black, yellow, magenta, and cyan.

In this tandem type image forming apparatus, image forming units of each color of black, yellow, magenta and cyan (for example, adopting an electrophotographic method) are arranged in parallel, and a portion facing each image forming unit is provided. A belt transport device is provided in which a transport belt is circulated and transported over a plurality of rolls, and a plurality of belts formed by each image forming unit on the transport belt directly or via recording paper (paper or OHP sheet). A transfer roller that is configured to sequentially transfer multiple color toner images (for example, JP-A-6-110390), or a transfer roll that contacts a photosensitive drum for an image carrier is provided for each image forming unit. It includes a device in which a recording paper is conveyed by a photosensitive drum and a transfer roll (for example, Japanese Patent Application Laid-Open No. 7-319254).

The image forming apparatus includes a document table, an image reading unit that optically scans a document placed on the document table, and reads image data from the document, and an image data read by the image reading unit. And an image processing unit that separates the color image data into color image data of each color and performs image processing on the color-separated image data.

As shown in FIG. 13, the image processing section has four photosensitive drums 11 corresponding to respective colors, and a charging device 6, an exposure device 7, and a developing device 8 are provided along the periphery of each photosensitive drum 11. And a transfer device 9.

The four photosensitive drums 11 are arranged so that their rotation axes are aligned with one another.
Is provided along the transfer belt 4, and the toner image developed on the photosensitive drum 11 is transferred to the transfer belt 4.

The power of one drive motor for rotating each photosensitive drum 11 at a constant speed is transmitted to each photosensitive drum 11 by a photosensitive drum driving device 10 described below.

As shown in FIG. 1, output shafts (rotary shafts) 12 of the respective photosensitive drums 11 are arranged in parallel in a horizontal line, and are supported by a pair of frames 14. Each output shaft 12
Is connected to a first friction wheel 21. Adjacent first
A second friction wheel 22 is disposed between the friction wheels 21 and 21. The outer diameter of the second friction wheel 22 is
Is set larger than the shortest distance between the outer peripheral surfaces of the friction wheels 21, 21, and the rotation axis thereof is not fixed to the frame 14, and can be freely moved in the vertical and horizontal directions. Flywheels 23 are fixed to both ends of the rotating shaft 12 of the second friction wheel 22. The belt 13 is wound around the drive pulley 17 connected to the drive shaft 16 of the motor 15 and the second pulleys 22. A pressure roller 19 is provided between the drive pulley 17 and the second friction wheel 22 to secure a winding angle with the drive pulley 17. A tension is applied to the winding element by using a pressure pulley (tension pulley) or by moving a drive pulley, and a contact pressure is applied to the friction wheel by the tension.

The first friction wheel 21 and the second friction wheel 22
A high friction material made of rubber, elastomer, resin (thermoplastic resin such as urethane resin or thermosetting resin) or the like may be provided on at least one outer peripheral surface (contact surface), or fine irregularities may be provided. For example, 10 μm to 5 μm
A metal surface having irregularities of 0 μm may be provided.

Further, at least one contact surface of the friction wheels 21 and 22 may be formed of granular ceramics or a fiber-reinforced thermoplastic resin. Further, a wear-resistant material such as tungsten carbide may be sprayed on the contact surface. Further, magnets may be attached to the friction wheels 21 and 22, and the contact pressure between the friction wheels may be increased by the magnetic force.

Note that a flat belt, V
Belts, toothed belts, round belts and the like can be employed.

According to the acceleration / deceleration device 10 having the above structure, the contact pressure generated between the friction wheels 21 and 22 by the belt 13 and the first
By using the biting force between the second friction wheels 21 and 22, a transmission force can be generated to transmit a rotational driving force. Further, with a simple configuration in which the outer diameter ratio of the two friction wheels 21 and 22 is changed, a larger reduction ratio (or speed increase ratio) can be obtained.

Further, there is no loud noise, generation of vibration, backlash, etc., which are found in the conventional meshing transmission of gears, toothed belts, chains and the like. Further, there is no problem in that there is no rotational displacement between the four photoconductor drums 11 and the images formed on the photoconductor drums 11 are mutually shifted. Therefore, since the mutual displacement of the photosensitive drums 11 is prevented, color shift and color unevenness do not occur in the formed image.

Further, by providing the flywheel 23 on the rotating shaft 12 of the second friction wheel 22, vibration energy is accumulated and released by the flywheel 23, and vibration is effectively suppressed. This flywheel is a friction wheel 2
On the other hand, by rotating at a high speed, a larger amount of inertia can be provided, so that a high effect can be obtained even if the outer diameter of the flywheel is small. Further, since the transmission rigidity between the friction wheels is high, the resonance frequency is high, and low frequency vibrations particularly harmful to an image are not generated. (Second Embodiment) As shown in FIG. 2, a second friction wheel 22 is further disposed between first friction wheels 21 on the center side, and an outer surface of the second friction wheel 22 is provided on the second friction wheel 22. A pressure roller 24 may be provided so as to press the belt 13. The pressure roller 24 is rotatably supported by a bracket 25 in a pair. Also, in this embodiment, each second friction wheel 2
The flywheels 23 are fixed to both ends of each of the two. (Third Embodiment) As shown in FIG.
2, the second pulleys 32 may be fixed respectively. (Fourth Embodiment) As shown in FIG. 4, a second friction wheel 22 is further disposed between first friction wheels 21 on the center side, and a second friction wheel 22 is provided on the second friction wheel 22. 2 pulley 32
And a pressure roller 24 may be provided so as to press the belt 13 against the outer surface of the second pulley 32. The pressure roller 24 is rotatably supported by a bracket 25 in a pair.

Next, an accelerating / decelerating device 10 used in the above-mentioned photosensitive drum driving device or other driving device of the rotating body.
Will be described.

As shown in FIG. 5, a drive-side friction wheel 2 that contacts two rollers (friction wheels) 1 and 3 at a wedge angle α is
Considering the case where the transmission torque T is transmitted to the output shaft while being held between the holding roller 3 and the driven-side friction wheel 1, the following equation is obtained.

2F · cosα = 2N · sinα∵F = N · tanα In order to use a force larger than that, it is sufficient to increase the α angle in order to increase the wedge effect.

The generated transmission force Ft is Ft = μ · N, and in order to transmit power without gross slip, Ft ≧ F∵α ≧ tan ⁻¹ μ must be satisfied.

In FIG. 5, N is the contact pressure of the contact surface, F is the tangential force of the contact surface, μ is the dynamic friction coefficient of the contact surface,
Indicates a pressing force, and α indicates a wedge angle.

The acceleration / deceleration device shown in FIG. 6 shows the most basic configuration. (Embodiment 1 of Acceleration / Deceleration Device) As shown in FIG. 6, a first support plate 41 is fixed to a side surface of the motor 15 on the drive shaft side, and a second support plate is interposed between the first support plate 41 and a gap. 42 is fixed.

The output shaft 12 and the shaft 44 of the holding roller 43 are supported between the first and second support plates 41 and 42. The second drive-side second wheel extends between the first friction wheel 21 fixed to the output shaft 12 and the holding roller 43.
A friction wheel 22 is arranged. A deceleration pulley 44 is fixed to the second friction wheel 22. The belt 13 is wound between the deceleration pulley 44 and the drive pulley 17 fixed to the drive shaft 16 of the motor 15. The outer diameter of the second friction wheel 22 is equal to the final friction wheel 21 and the holding roller 43.
Is set to be larger than the shortest distance between the outer circumferences of the drive wheels, and the driving-side friction wheel 22
1 and the outer peripheral surface of the holding roller 43.

When the driving pulley 17 is rotated by the rotation of the motor 15, the rotational driving force is transmitted to the reduction pulley 44 and the driving-side friction wheel 22 by the belt 13, and the final-stage friction wheel 21 that comes into contact with the friction wheel 22. Is transmitted to

The output shaft 1 will be described in further detail below.
The two first friction wheels 21 attached to 2 are paired. In order to increase the friction coefficient of the surface, a thin rubber layer is provided here. The friction wheel 22 on the driving side has a pulley 44 on which the drive belt 13 is hung at the center, and has friction wheels 22 serving as driving means on both sides thereof. Here, friction wheel 2
(2) In order to increase the friction coefficient of the surface, shot blasting is performed, and the surface is provided with irregularities of 20 to 30 μm, and the surface is hardened by tuftride or hard chrome plating.

To hold the friction wheel 22 in the left-right direction, a hard ball is embedded in the center of the shaft of the driving-side friction wheel 22 with a slight gap provided between the main body frames 41 and 42.
By applying grease, a part is held. A holding roller 43 is provided on the driving-side friction wheel 22, and holds the driving-side friction wheel 22 between the driving-side friction wheel 21 and the deceleration-side friction wheel 21. At this time, the contact angle between the three pairs of friction wheels is set to an angle that produces a sufficient wedge effect.

The belt 13 is wound around a pulley 44 provided on the motor 15 and the driving-side friction wheel 22, and an appropriate tension is generated on the belt 13. As a result, a contact pressure is applied to the friction wheel 22, and a strong driving force can be generated by a synergistic effect with the wedge effect of the friction wheels 21 and 22. (Embodiment 2 of Acceleration / Deceleration Device) As shown in FIG. 7, in this embodiment, the holding roller 43 and the friction wheel 22 on the driving side are used.
Are disposed at two locations, and the belt 13 is wound between the two reduction pulleys 44 and the drive pulley 17 fixed to the drive shaft 16 of the motor 15. (Embodiment 3 of acceleration / deceleration device) FIG. 8 shows still another acceleration / deceleration device. As shown in FIG. 8, a pair of output shafts 12 are arranged on both left and right sides, and a final-stage friction wheel 21 is fixed to each output shaft 12. A drive-side friction wheel 22 is disposed in contact between the two final-stage friction wheels 21, 21, and a belt extends between the reduction pulley 44 and the drive pulley 17 fixed coaxially with the drive-side friction wheel 22. 13 are wound. (Embodiment 4 of Accelerator / Decelerator) As shown in FIG. 9, the rotational speeds of the output shafts 12, 12 may be made different by changing the diameters of the two final-stage friction wheels 21, 21. (Embodiment 5 of Acceleration / Deceleration Device) FIG. 10 shows a speed increasing device. As shown in FIG. 10, the output shaft 12 and the holding roller 43 are respectively arranged on both sides, the output shaft 12 becomes the final-stage friction wheel 21, and the flywheel 47 is fixed to the output shaft 21. A large-diameter drive-side friction wheel 22 is arranged between the final-stage friction wheel 21 and the holding roller 43 in a contact state. A belt 13 is wound therebetween. (Embodiment 6 of acceleration / deceleration device) FIG.
FIG. As shown in FIG. 11, three output shafts 12 are arranged in a line at an interval, and a final-stage friction wheel 21 is fixed to each output shaft 12. A driving-side friction wheel 22 is disposed in contact between the adjacent final-stage friction wheels 21, and the belt 13 is wound around a driving pulley and a deceleration pulley 44 fixed coaxially with the driving-side friction wheel 22. Have been.

A speed reducer or a speed increasing device having four output shafts 12 can be constructed in the same configuration as described above.
For example, it can be configured as shown in FIG.
4 already indicated. (Embodiment 7 of Acceleration / Deceleration Device) The acceleration / deceleration device shown in FIG. 12 has a connecting friction wheel 47 and a backup roller 48 interposed between a pair of left and right final-stage friction wheels 21, 21.

In any of the above configurations, the friction wheel is
Prepare a pair (one friction wheel may be replaced with a roller) and set them so that they contact at a wide angle. The set angle is such that the center friction wheel among the three pairs of friction wheels is put on the friction wheels on both sides in a free state without a bearing portion or the like so as to be supported by the friction wheels on both sides. Belt 1 for central friction wheel
A pulley around which a winding member such as No. 3 is wound is provided coaxially, a winding member is wound around the pulley, and a transmission member such as a drive pulley or a sprocket provided on the motor is wound with an appropriate tension.

The tension may be generated by the expansion and contraction of the transmission member, or may be applied by a spring or the like via a tension pulley or the like. By the tension generated by this winding member,
Contact pressure is generated in three pairs of friction wheels. (The angle is set so that contact pressure is generated.) Also, due to the force generated in the contact pressure direction, the center friction wheel does not need a bearing portion for supporting the friction wheel, and the friction wheels are always connected to each other. Can be contacted.

The three pairs of friction wheels can generate a transmission force commensurate with the load by a wedge effect generated by the friction coefficient and the contact angle of the transmission member of the friction wheel.

In order to further increase the contact pressure of the friction wheel, a friction wheel incorporating a magnetic material and a magnet can be used. Also, as described above, the outer peripheral surface (contact surface) of the friction wheel
May be treated or provided with a friction material to increase the coefficient of friction.

[0053]

According to the image carrier driving device of the image forming apparatus of the present invention, a plurality of image carriers and a first friction wheel connected to the output shaft of each image carrier are connected to the first friction wheel. A second friction wheel disposed between the first friction wheels and in contact with an outer peripheral surface of each of the first friction wheels; a winding transmission element for transmitting power from a drive shaft to the second friction wheels; Is provided, it is possible to prevent the occurrence of rotational displacement between the plurality of image carriers, and to prevent color shift and color unevenness of an image due to mixing of colors.

In particular, by providing the flywheel on the second friction wheel, vibration energy is accumulated and released by the flywheel, and the vibration is more effectively suppressed.

Further, according to the acceleration / deceleration device of the present invention, it is possible to provide an acceleration / deceleration device having low noise, low vibration, and high transmission rigidity. In addition, since an axial load proportional to the load is generated, a loss at a low load is small, and a highly efficient acceleration / deceleration device can be provided. Further, it is possible to provide an inexpensive, stable, maintenance-free accelerating / decelerating device.

Further, it is possible to provide an acceleration / deceleration device having a plurality of output shafts having the above-mentioned advantages or having a plurality of output shafts having different rotation speeds.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a photosensitive drum driving device according to the present invention, wherein 1A is a plan view thereof and 1B is a side view thereof.

FIG. 2 shows another embodiment of the photosensitive drum driving device of the present invention, wherein 2A is a plan view and 2B is a side view.

3A and 3B show still another embodiment of the photosensitive drum driving device of the present invention, in which 3A is a plan view and 3B is a side view.

FIG. 4 shows still another embodiment of the photosensitive drum driving device of the present invention, wherein 4A is a plan view and 4B is a side view.

FIG. 5 is a diagram for explaining the principle of the acceleration / deceleration device of the present invention.

FIG. 6 shows an embodiment of the acceleration / deceleration device of the present invention, and shows 6A.
Is a side view, and 6B is a cutaway side view.

FIG. 7 shows another embodiment of the acceleration / deceleration device of the present invention.
A is a side view thereof, and 7B is a cutaway side view thereof.

FIG. 8 shows a further embodiment of the acceleration / deceleration device of the present invention, wherein 8A is a side view thereof, and 8B is a cutaway side view thereof.

9A and 9B show still another embodiment of the acceleration / deceleration device of the present invention, wherein 9A is a side view thereof, and 9B is a cutaway side view thereof.

FIG. 10 shows a further embodiment of the acceleration / deceleration device of the present invention, wherein 10A is a side view thereof and 10B is a cutaway side view thereof.

11 shows still another embodiment of the acceleration / deceleration device of the present invention, where 11A is a side view thereof and 11B is a cutaway side view thereof.

12 shows still another embodiment of the acceleration / deceleration device of the present invention, in which 12A is a side view thereof, and 12B is a cutaway side view thereof.

FIG. 13 is a schematic view of a main part of the image forming apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 image carrier driving device 11 photoconductor drum 12 output shaft 13 belt 15 motor 16 drive shaft 17 drive pulley 19 pressure roller 21 first friction wheel 22 second friction wheel 23 flywheel 24 pressure roller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16H 7/12 F16H 7/12 A 3J103 7/14 7/14 A 13/04 13/04 C G03G 15 / 00 550 G03G 15/00 550 21/00 350 21/00 350 F-term (reference) 2H030 AA01 AB02 BB02 BB41 BB71 2H035 CA07 CB01 CG03 2H071 CA02 CA05 DA09 DA15 EA18 3J049 AA01 AB03 BA01 BB05 BB08 ABA1A03 BD01 BE03 DA01 EA04 EA06 EB03 EC03 EC08 ED07 ED18 FA10 3J103 AA02 AA12 AA13 AA51 AA66 BA37 BA38 BA43 CA52 DA05 DA06 FA04 FA16 FA18 FA19 FA26 GA02 GA52 HA03 HA04 HA16 HA35 HA48 HA51 HA53 HA54

Claims (7)

[Claims] 1. An image carrier driving device used in a tandem image forming apparatus in which a plurality of image carriers are arranged in parallel, a first friction wheel connected to an output shaft of each image carrier, A second friction wheel disposed between the adjacent first friction wheels and in contact with an outer peripheral surface of each first friction wheel; and a winding for transmitting power from a drive shaft to the second friction wheels. An image carrier driving device, comprising: a transmission element. 2. The image carrier driving device according to claim 1, further comprising a pressure roller for increasing a tension of the winding element, and pressing the second friction wheel against a contact surface of the first friction wheel. 3. The image carrier driving device according to claim 1, wherein a flywheel is provided on a rotation shaft of the second friction wheel. 4. The second friction wheel according to claim 1, wherein an outer diameter of the second friction wheel is set to be larger than a shortest distance between outer peripheral surfaces of the adjacent first friction wheels. Image carrier driving device. 5. A first friction wheel that is pivotally supported, a third friction wheel or holding roller that is spaced apart from the first friction wheel, and between the first and third friction wheels. Or first
A second friction wheel, which is disposed between the friction wheels and the holding rollers, and has an outer diameter larger than the shortest distance between the outer peripheral surfaces of the two friction wheels or the outer peripheral surfaces of the first friction wheel and the holding rollers;
And a winding transmission element for transmitting a rotational force from a drive shaft to the second friction wheel, wherein the second friction wheel makes the first or second friction wheel by the winding element.
A speed increasing / decelerating device adapted to be in pressure contact with the peripheral surface of the friction wheel. 6. The acceleration / deceleration according to claim 5, wherein the rotation shafts of the first friction wheel and the third friction wheel function as output shafts, and the rotation speeds of the respective output shafts are set to be different from each other. apparatus. 7. One of the first friction wheel and the second friction wheel is made of a magnetic material, and a magnet is attached to the other friction wheel, and a contact force between the first and second friction wheels is increased by a magnetic force. The acceleration / deceleration device according to claim 5, wherein