JP2002195374A - Driving mechanism for rotating body and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving mechanism for a rotating body capable of obtaining necessary moment of inertia, even if using a comparatively small-sized flywheel, and secularly stably rotating the rotating body and an image forming device having the mechanism. SOLUTION: This driving mechanism 110 for the rotating body has the rotating body 101 rotating with a shaft 1 as a center, a first flywheel 14 which is disposed on the shaft 1 and rotates together with the rotating body 101, a second flywheel rotated and driven since driving force of the first flywheel 14 is transmitted and a driving force transmitting mechanism 31 for transmitting driving force of the first flywheel 14 to the second flywheel. This image forming device has the driving mechanism 110.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving mechanism for a rotating body such as an image carrier and an image forming apparatus having the same.

[0002]

2. Description of the Related Art Image forming apparatuses such as printers, electrophotographic copying machines, and facsimile machines are provided with a rotating body such as an image carrier. Because it is necessary to maintain high accuracy and constant,
2. Description of the Related Art A driving mechanism of a rotating body using a flywheel that rotates integrally with the rotating body is known. FIG. 5 shows an example of such a mechanism conventionally used. In this example, a photoconductor drum (hereinafter, referred to as a “photoconductor”) 10 as an image carrier is used.
1 is provided as a rotating body. The photoconductor 101 has a pin 2
As a result, it is integrated with the shaft 1 and rotates about the shaft 1. Axis 1
Are the bearings 4 with respect to the support plate 3 at both ends of the photoreceptor 101.
It is rotatably supported via. The shaft 1 is also rotatably supported by a bearing 7 on a motor mounting plate 6 fixed to the outer surface of the support plate 3 for supporting the motor 5.

The shaft 8 of the motor 5 is located between the support plate 3 and the motor mounting plate 6, and a drive pulley 9 is fixed to the shaft 8. A driven pulley 11 is fixed between the support plate 3 and the motor mounting plate 6 of the shaft 1 by a pin 10, and a timing belt 1 is provided between the driven pulley 11 and the driving pulley 9.
2 is wound. A flywheel 14 is fixed to the shaft 1 on the opposite side of the driven pulley 11 across the motor mounting plate 6 by a pin 13. The photoreceptor 101 is driven to rotate by the motor 5. At this time, the flywheel 14 is driven to rotate integrally with the photoreceptor 101, so that the rotation of the photoreceptor 101 is stabilized.

The flywheel stabilizes the rotation by preventing the speed fluctuation of the rotating body by the inertial energy of the rotation. Here, the inertia energy KE can be expressed as KE = 1/2 × Jω ² when the moment of inertia is J and the angular velocity is ω. Further, moment of inertia, and the distance from the axis of rotation of the flywheel to the mass dm of the minute portion and r, is represented by J = ∫ _dm r ² _dm. As described above, since the moment of inertia is proportional to the square of the radius, it is desirable to increase the outer diameter of the flywheel in order to cope with the accuracy of the gears and pulleys of the rotating body drive system and various load fluctuations on the rotating body.

However, when the outer diameter of the flywheel is increased, the size of the apparatus is increased, and the weight of the flywheel itself is increased. Therefore, it is necessary to increase the rigidity of the shaft for supporting the flywheel and the structure around it. ,
There was also a problem with maintainability. As a means for stabilizing the rotation of the rotating body, there has been known a configuration in which a brake material is provided in contact with a gear or the like provided on the surface of the rotating body or a shaft of the rotating body in addition to the flywheel. However, when the brake material is brought into contact, the driving load of the rotating body increases, so it is necessary to increase the size of the driving source of the rotating body, that is, the motor. Become.

In a structure using a flywheel, Japanese Patent Laid-Open Publication No. Hei 10-288915 discloses that a driving force is transmitted to a flywheel to a large-diameter friction wheel disposed on a shaft of a photosensitive drum as a rotating body. There has been proposed a configuration in which a small-diameter friction wheel is brought into contact with and driven to rotate, thereby increasing the rotation speed of the flywheel and obtaining a required moment of inertia even with a relatively small flywheel.

[0007]

However, in such a configuration, when the friction wheel transmitting the driving force to the flywheel is eccentric, rotation stability cannot be obtained, and when the friction wheel wears, the rotation of the friction wheel becomes poor. There is a problem that stability is reduced. As another configuration having a friction wheel that transmits a driving force to the flywheel, as disclosed in Japanese Patent Application Laid-Open No. 4-75065, the rotation of the flywheel is greater than the rotation of the photosensitive drum as a rotating body. There has been proposed a configuration in which a rotating body that transmits a driving force to a flywheel so as to be faster is disposed so as to abut on an end portion of a peripheral surface of a photosensitive drum. However, in this configuration, a friction wheel is still eccentric. There is a problem in that rotation stability cannot be obtained, and when the friction wheel is worn, rotation stability is reduced.

The present invention provides a driving mechanism for a rotating body which can obtain a required moment of inertia even with the use of a relatively small flywheel and can stably rotate the rotating body over time. It is an object to provide an image forming apparatus having this.

[0009]

According to a first aspect of the present invention, there is provided a rotating body rotating about a first axis and a rotating body disposed on the first axis. A first flywheel rotating integrally, a second flywheel rotationally driven by transmitting a driving force of the first flyhole, and transmitting a driving force of the first flywheel to the second flywheel; A driving mechanism for a rotating body having a driving force transmission mechanism.

According to a second aspect of the present invention, in the driving mechanism for a rotating body according to the first aspect, the second flywheel is provided with the first flywheel.
Are arranged on a second axis different from the second axis.

[0011] The invention according to claim 3 is the invention according to claim 1 or 2.
In the driving mechanism for a rotating body described above, the driving force transmission mechanism includes a roller that elastically contacts the outer peripheral surface of the first flywheel at a constant pressure.

According to a fourth aspect of the present invention, in the driving mechanism for a rotating body according to the third aspect, the driving force transmitting mechanism has a supporting member for rotatably supporting the roller, and the supporting member is provided with a first supporting member. It is characterized by being rotatably supported by one shaft.

According to a fifth aspect of the present invention, in the driving mechanism of the rotating body according to the fourth aspect, the roller has a first position at which the driving force of the first flywheel can be transmitted to the second flywheel. The second flywheel is movable between a second position not transmitting the driving force of the first flywheel to the second flywheel, and the second position when the rotation of the first flywheel is stopped. And moves to the first position when the first flywheel starts rotating.

The invention according to claim 6 is the invention according to claims 3 to 5
In the driving mechanism for a rotating body according to any one of the above, the roller is an elastic body.

The invention according to claim 7 is the first to sixth aspects of the present invention.
The driving mechanism for a rotating body according to any one of
Is characterized in that the angular velocity of rotation of the flywheel is greater than the angular velocity of rotation of the first flywheel.

[0016] The invention according to claim 8 is the invention according to claims 1 to 7.
The driving mechanism for a rotating body according to any one of
Is characterized by having a smaller diameter than the first flywheel.

According to the ninth aspect of the present invention, there are provided the first to eighth aspects.
In the driving mechanism for a rotating body according to any one of the above, the rotating body is an image carrier.

According to a tenth aspect of the present invention, there is provided an image forming apparatus having the rotary member driving mechanism according to any one of the first to ninth aspects.

[0019]

FIG. 1 shows an image forming apparatus to which the present invention is applied. The image forming apparatus 100 includes a photoconductor drum (hereinafter, referred to as a “photoconductor”) 101 as an image carrier that is a rotating body that is driven to rotate about the axis 1 in the direction of arrow A, and the photoconductor 1.
And a laser beam 103 for forming a latent image on the charged photoconductor 101.
An exposure device (not shown) as an exposure device for performing optical scanning by emitting light, a developing device 104 as a development device for developing a latent image on the photoconductor 101 after exposure, and a toner on the photoconductor 101 obtained by development. A transfer device 105 as a transfer device for transferring an image onto a sheet P; a cleaning device 106 as a cleaning device for cleaning the surface of the photoreceptor 101 after the transfer; A static eliminator 105 (not shown),
A registration roller 107 that conveys the sheet P at a predetermined timing toward a portion where the photoconductor 101 and the transfer device 104 face each other.
And a guide plate 108 as a guide for guiding the sheet P to which the toner image has been transferred, and the fixing device 1 as a fixing unit for fixing the sheet P guided by the guide plate 108
09.

The charging roller 1 provided in the charging device 102
02a, developing roller 104 provided in developing device 104
a, a transfer roller 105a provided in the transfer device 105,
Fur brush 10 provided in cleaning device 106
6a rotates in the B direction, the C direction, the D direction, and the E direction, respectively. The B direction, the C direction, and the D direction are all
The direction E is the direction of movement in the same direction as the direction A at the position facing the photosensitive member 101, and the direction E is the direction of movement in the direction opposite to the direction A at the position facing the photosensitive member 101.

The cleaning device 106 removes toner and fine paper dust remaining on the surface of the photosensitive member 101 by the fur brush 106a. The fixing device 109 includes a heating roller 10 that is driven to rotate in the F direction.
9a and a pressure roller 10 pressed against and driven by the pressure roller 9a
9b, the toner image on the sheet P is fused and fixed to the sheet P by heating by a heating source (not shown) built in the heating roller 109a and pressing by the pressing roller 109b. .

As shown in FIG. 2, the image forming apparatus 100
Is provided with a rotating body driving mechanism 110 for keeping the rotation of the photoconductor 101 constant with high accuracy. In the driving mechanism 110 for the rotating body, the same configurations as those of the conventional mechanism shown in FIG. 5 are appropriately omitted from illustration or the same reference numerals, and description is omitted. The photoreceptor 101 is integrated with the shaft 1 by a pin 2 and rotates about the shaft 1. A flywheel 14 as a first flywheel is fixed to the shaft 1 by a pin 13. Flywheel 1
An elastic body, specifically, a roller 15 having a rubber layer 16 is in contact with the outer peripheral surface of the roller 4 to increase frictional resistance on the outer peripheral surface. The roller 15 is rotatably supported by a frame 19 having a U-shaped cross section by supporting a shaft 17 of the roller 15 with a bearing 18.

A support member 20 is provided outside the frame 19 so as to surround the frame 19. Support member 20
Is rotatably supported on the shaft 1 via a bearing 21. On each side of the support member 20, long holes 22 and 23 long in the radial direction of the flywheel 14 are formed.
A bearing 18 is slidably fitted in the slot 2, and a guide 24 projecting from the frame 19 is slidably fitted in the elongated hole 23. A pressing spring 25 as an elastic body is disposed between the frame body 19 and the supporting member 20, and the roller 15 is substantially fixed to the outer peripheral surface of the flywheel 14 by the urging force of the pressing spring 25. It is in elastic contact with pressure. A flywheel support 26 extends upward from a side surface of the motor mounting plate 6 that supports the motor 5 that is a DC brushless motor as a driving source, and faces the support member 20.

As shown in FIG. 3, a shaft 27 which is different from the shaft 1 and is non-coaxial with the shaft 1 is provided on a side surface of the flywheel support portion 26, and a bearing 32 is provided on the shaft 27. A flywheel 28 as a second flywheel is rotatably supported through the intermediary of the flywheel 28. The flywheel 28 has a large-diameter main body 29 and a transmitted portion 30 having a small diameter and capable of coming and coming from the roller 15. The main body 29 has a smaller diameter than the flywheel 14. As shown in FIG. 4, when the flywheel 14 is driven to rotate in the direction indicated by the arrow G, the roller 15 rotates in the H direction, and the roller 15 applies the driving force of the flywheel 14 to the transmitted portion 30. With the transmission, the flywheel 28 is driven to rotate in the arrow I direction. The G direction corresponds to the photosensitive member 101 in FIG.
This is the same direction as the direction A, which is the rotation direction of. The roller 15 also elastically contacts the flywheel 28 by the action of the pressing spring 25.

In FIG. 2, the roller 15, the frame 19, the support member 20, the bearing 21, and the pressing spring 25 constitute a driving force transmission mechanism 31 for transmitting the driving force of the flywheel 14 to the flywheel 28. The diameters of the flywheel 14, the roller 15, the body 29 of the flywheel 28, and the transmitted portion 30 are set such that the angular velocity of rotation of the flywheel 28 is greater than the angular velocity of rotation of the flywheel 14. The support member 20 for supporting the roller 15 is rotatably supported by the bearing 21 with respect to the shaft 1. The roller 15 is a first member indicated by a solid line in FIG.
And a second position indicated by a two-dot chain line in FIG.

In a state where the photoconductor 101 is not driven to rotate and the rotation of the flywheel 14 is stopped, the weight of the roller 15, the support member 20, etc.
The second roller 15 is separated from the driven portion 30 and does not transmit the driving force of the flywheel 14 to the flywheel 28.
When the photoconductor 101 is driven to rotate and the flywheel 14 starts rotating, the photosensitive member 101 moves to the first position in accordance with the movement of the outer peripheral surface of the flywheel 14, and the flywheel 28 drives the flywheel 14. To communicate.

As a result, the driving load on the motor 5 at the start of rotation of the photosensitive member 101 is reduced, and the rotation transmission to the flywheel 28 is started with the photosensitive member 101 and the flywheel 14 starting to rotate. By doing so, the load on the motor 5 when the rotation of the flywheel 28 starts is also reduced. When both the flywheel 14 and the flywheel 28 are driven to rotate at a predetermined number of rotations, the moment of inertia of these rotations is large enough to keep the rotation of the photoconductor 101 constant with high accuracy. ing.

The diameters of the flywheel 14, the roller 15, the main body 29 of the flywheel 28, and the transmitted portion 30,
The weight of the flywheel 14 and the flywheel 28 is such that the inertia moment of rotation of the flywheel 14 and the flywheel 28 increases the rotation of the photosensitive member 101 in a state where both the flywheel 14 and the flywheel 28 are rotationally driven at a predetermined rotation speed. It is designed to be large enough to maintain constant accuracy.

Since the image forming apparatus 100 has the above-described configuration, the photosensitive member 101 charged in the charging step by the charging device 102 is rotated in the direction of arrow A to form a latent image in the exposure step by the laser beam 103, and a developing device. 10
After the development step by Step 4, the transfer step by the transfer device 105, the cleaning step by the cleaning device 106, and the charge removal step by the charge removal device, the process returns to the charging step. The toner image transferred onto the sheet P in the transfer process is
The image is fixed on the paper P by the transfer process at 09.
The sheet P on which the toner image has been fixed is discharged outside the apparatus.

In these image forming steps, the moment of inertia of rotation by the flywheel 14 and the flywheel 28 keeps the rotation of the photosensitive member 101 constant with high accuracy.
Since the rotation of the photoconductor 101 is stabilized, high-quality image formation can be performed without causing image displacement or blurring. Further, the roller 15 is elastically provided with the flywheel 14,
Due to the contact with the roller 28, the rotation of the photoconductor 101 is maintained at a high accuracy and constant even if the roller 15 is worn over time.

Although the embodiments of the present invention have been described above, the rotating body is not limited to the photosensitive drum, but a belt-like photosensitive body is wound around, and a driving roller for driving the photosensitive body is used. It is possible to apply a roller that is to be performed.

[0032]

According to the present invention, there are provided a rotating body rotating about a first axis, a first flywheel disposed on the first axis and rotating integrally with the rotating body, and a first flywheel. Since the driving mechanism of the rotating body includes the second flywheel that transmits the driving force of the hole and is driven to rotate, and the driving force transmission mechanism that transmits the driving force of the first flywheel to the second flywheel. The required moment of inertia can be obtained even when a small flywheel is used as compared with the case where only one flywheel is used, and the rotation of the rotating body can be increased while suppressing the enlargement of the mechanism and the driving source. It is possible to provide a driving mechanism for a rotating body that can be stably maintained with high accuracy.

If the second flywheel is provided on a second shaft different from the first shaft, the driving force transmission mechanism can be made relatively simple and the size of the mechanism and the driving source can be increased. It is possible to provide a driving mechanism of the rotating body that can keep the rotation of the rotating body constant and stable with high accuracy while suppressing it.

If the driving force transmission mechanism has a roller that elastically abuts the outer peripheral surface of the first flywheel at a constant pressure, the gear and belt are in comparison with the structure in which the gear and the belt abut on the first flywheel. As a result, the transmission of vibration and speed fluctuations can be reduced, the transmission of driving force can be ensured, and it is not necessary to strictly adjust the position of the first flywheel, so that assembly and maintenance are easy, It is possible to provide a driving mechanism for a rotating body that can maintain the rotation of the rotating body with high accuracy and stably and stably even when deterioration such as wear occurs with time.

If the driving force transmitting mechanism has a supporting member for rotatably supporting the roller, and the supporting member is rotatably supported on the first shaft, the roller is connected to the first shaft. And a driving mechanism for the rotating body that can maintain a contact state with the first flywheel.

A roller has a first position at which the driving force of the first flywheel can be transmitted to the second flywheel and a second position at which the roller does not transmit the driving force of the first flywheel to the second flywheel. Movable between the first position and the first position;
If the flywheel occupies the second position when the rotation of the flywheel is stopped and moves to the first position when the first flywheel starts rotating, the driving source at the time of starting the driving of the rotating body When the rotation load of the second flywheel starts at the start of rotation of the second flywheel by starting the rotation transmission to the second flywheel while the rotating body and the first flywheel have started to rotate, The load on the drive source is also reduced, and a drive mechanism for the rotary body that can keep the rotation of the rotary body after starting up stably with high accuracy and stability while suppressing an increase in the size of the drive source can be provided.

If the roller is made of an elastic body, it is possible to provide a driving mechanism for the rotating body which can secure the transmission of the driving force and can keep the rotation of the rotating body constant with high accuracy and stability. .

The angular velocity of rotation of the second flywheel is
If the rotation speed of the first flywheel is greater than the angular velocity, the diameter of the second flywheel can be reduced to obtain the same inertia force, and the rotation of the rotating body can be controlled with high precision while suppressing an increase in size. Thus, it is possible to provide a driving mechanism for the rotating body that can be kept constant and stable.

If the second flywheel is smaller in diameter than the first flywheel, the rotation of the rotating body can be maintained stably with high precision and high accuracy while suppressing an increase in size. A drive mechanism can be provided.

Assuming that the rotating body is an image carrier, by keeping the rotation of the rotating body constant with high accuracy and stability,
It is possible to provide a rotating body drive mechanism that can contribute to high-quality image formation.

Since the present invention resides in an image forming apparatus having such a rotating body driving mechanism, the rotation of the rotating body can be stably maintained with high accuracy and constant while suppressing an increase in size, and a high-quality image can be obtained. It is possible to provide an image forming apparatus capable of forming and having high user reliability.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an image forming apparatus to which the present invention is applied.

FIG. 2 is a side sectional view of a main part showing a driving mechanism of a rotating body to which the present invention is applied, provided in the image forming apparatus shown in FIG.

FIG. 3 is a side sectional view showing a support mode of a second flywheel.

FIG. 4 is a front view showing a mode of rotation of first and second flywheels and rollers.

FIG. 5 is a side sectional view showing a conventional rotating body driving mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st axis | shaft 14 1st flywheel 15 roller 20 support member 27 2nd axis | shaft 28 2nd flywheel 31 drive force transmission means 100 image forming apparatus 101 rotating body, image carrier 110 rotating body drive mechanism

Claims (10)

[Claims] A rotating body that rotates about a first axis;
A first flywheel disposed on the axis of the first flywheel and rotating integrally with the rotating body, a second flywheel that receives a driving force of the first flyhole and is driven to rotate, and a first flywheel. A driving force transmitting mechanism for transmitting a driving force to the second flywheel. 2. The driving mechanism for a rotating body according to claim 1, wherein the second flywheel is disposed on a second axis different from the first axis. . 3. A driving mechanism for a rotating body according to claim 1, wherein said driving force transmitting mechanism has a roller which elastically abuts on an outer peripheral surface of said first flywheel at a constant pressure. The driving mechanism of the rotating body. 4. A driving mechanism for a rotating body according to claim 3, wherein said driving force transmitting mechanism has a support member for rotatably supporting said roller, said support member being rotatable about a first shaft. A driving mechanism for a rotating body, wherein the driving mechanism is supported by the rotating body. 5. A driving mechanism for a rotating body according to claim 4, wherein said roller has a first position capable of transmitting a driving force of said first flywheel to a second flywheel, and a second flywheel. Movably between the first position and the second position which does not transmit the driving force of the first flywheel, and occupies the second position when the rotation of the first flywheel is stopped. When the flywheel starts rotating, the flywheel moves to a first position. 6. A driving mechanism for a rotating body according to claim 3, wherein said roller is an elastic body. 7. The driving mechanism for a rotating body according to claim 1, wherein an angular velocity of rotation of the second flywheel is greater than an angular velocity of rotation of the first flywheel. The driving mechanism of the rotating body. 8. The driving mechanism for a rotating body according to claim 1, wherein the second flywheel has a smaller diameter than the first flywheel. mechanism. 9. A driving mechanism for a rotating body according to claim 1, wherein said rotating body is an image carrier. 10. An image forming apparatus comprising the rotating body driving mechanism according to claim 1.