JP4049992B2 - Rotation drive device and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotational drive device that rotationally drives a rotating body and an image forming apparatus including the rotational drive device.
[0002]
[Prior art]
In an image forming apparatus such as an electrophotographic laser printer, a copying machine, a facsimile, a composite machine thereof, or a plotter printer, a surface of an image carrier that is one of rotating bodies is irradiated with a laser beam corresponding to image information. Thus, an electrostatic latent image is formed, and the electrostatic latent image is developed and transferred onto a sheet as an example of a transfer material to form an image. In the image forming apparatus, the image carrier is rotated by a rotary drive device that transmits a driving force from a rotary drive source to the image carrier by a drive transmission system. In such a rotary drive device, generally, when resonance occurs due to vibration in the rotation direction of a drive transmission system, a rotary drive source, or an image carrier, the rotational speed fluctuation of the image carrier becomes large. In view of this, the rotation of the rotating body is caused by adjusting the inertia of the rotating system including the rotating body and the torsion spring constant by providing an inertia member such as a dynamic damper or flywheel on the rotating shaft that supports the image carrier. An amplification region is set in a non-frequency region to suppress the rotational speed fluctuation of the image carrier.
[0003]
For example, in Japanese Patent Laid-Open No. 9-222826, rotational driving is performed so that each frequency of speed fluctuation due to eccentricity of a rotational driving device constituted by gears and meshing of gears is within an attenuation region in the frequency response of the rotational driving device. An invention is described in which the inertial mass of the inertia member in the system and the number of rotations and the number of teeth of the gear are set to prevent vibration amplification in the rotary drive device.
Japanese Patent Application Laid-Open No. 10-333385 discloses an image forming apparatus having an image carrier that is branched from a dual-shaft dual-gear motor in a rotary drive device and that is driven by a gear train and a rotary drive device to which an intermediate transfer member is pressed. Describes an invention in which a dynamic damper or a flywheel is provided on a drive shaft of a motor serving as a rotational drive source. According to the present invention, by suppressing the amplification of vibration due to the resonance of the motor by the effect of the dynamic damper or the flywheel, image disturbance occurs in the latent image formed on the surface of the image carrier by suppressing the vibration of the image carrier. Is preventing.
[0004]
[Problems to be solved by the invention]
One of the factors that hinders the high image quality of electrophotography is a phenomenon called jitter and banding. In particular, image quality has been improved by the introduction of digital technology, and the positional accuracy for each line of laser writing is strictly required. One of the factors governing this is the image carrier due to torsional vibration of the rotary drive system. Speed fluctuation. Therefore, the reduction of torsional vibration in this rotational drive system is an important technology for the development of products that can obtain high-quality images.
[0005]
It is said that the visual sensitivity of an image that recognizes the deviation of a line formed on a certain object as a human being is easily noticeable in a certain line pitch range, although there are individual differences. Looking at the relationship between the visible sensitivity and the rotation speed of the image carrier, the visualization spatial frequency for the image carrier can be obtained by dividing the linear velocity (rotation speed) of the image carrier by the line pitch. For example, when the line pitch is in the range of 0.3 to 2.0 line / mm, and the linear velocity (rotational speed) of an image carrier that is generally used at present is divided by this line pitch, the range of the visualization spatial frequency Becomes a wide frequency range of several Hz to several hundred Hz. For this reason, in order to obtain high image quality, it is required to avoid such image shift in a wide frequency range, that is, fluctuation in the rotational speed of the image carrier. Further, as the image forming speed of the image forming apparatus increases, the rotation speed of the image carrier increases, so that vibrations are expected to occur in a higher frequency band than the current state, and in a wider frequency range. It is desirable to reduce vibration generation.
[0006]
An object of the present invention is to provide a rotary drive device that can reduce vibration components that cause fluctuations in rotational speed and can obtain stable rotation of a rotating body.
SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can reduce image deterioration caused by rotational vibration and obtain high image quality.
[0007]
[Means for Solving the Problems]
To achieve the above object, the present invention includes a rotating system that supports a rotating body, a drive system that has a rotation drive source that rotationally drives the rotating system, and a drive transmission system that connects the rotating system and the drive system. The provided rotation drive device is characterized in that a centrifugal pendulum type vibration absorbing means is provided at least in the rotation system.
[0008]
  The centrifugal pendulum type vibration absorbing means has a rotating member provided on a rotating shaft that can rotate integrally with the rotating body, and has a plurality of holes formed therein, and a first pendulum member that is loosely fitted in the plurality of holes, The plurality of holes are characterized in that they are centered at the same distance from the rotation center of the rotating member, are arranged so that the respective radii are equal and at equal angles from the rotation center..
[0012]
The rotational drive device according to the present invention has a center at the same distance from the rotation center on a concentric circle different from the radius from the rotation center to the center of the hole in at least one of the rotation member, inertial body, gear or pulley. It is characterized by having a plurality of holes arranged so as to have the same radius and an equal angle from the center of rotation, and a second pendulum member loosely fitted in each hole.
[0013]
The rotary drive device according to the present invention is characterized by having a member that holds the first pendulum member and / or the second pendulum member in a loosely fitted state in the hole and / or hole.
[0014]
The rotary drive device according to the present invention is characterized in that the surface of the first and / or second pendulum member is an elastic member.
[0020]
An image forming apparatus for forming an image by rotating an image carrier according to the present invention includes any one of rotational drive devices, and rotationally drives the image carrier using any of the rotational drive devices. It is a feature.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
  Figure1 and 2 are perspective views showing a schematic configuration of a rotary drive device to which the present invention is applied. In FIG. 1, the rotation drive device includes a rotation system 60 that rotatably supports the rotating body 1, a drive system 61 having an electric motor 5 as a rotation drive source that rotationally drives the rotation system 60, and a rotation system 60. A drive transmission system 62 that connects the drive system 61 is provided.
[0022]
The rotating system 60 includes a columnar rotating shaft 2 provided so as to be rotatable integrally with the rotating body 1, a flywheel 4 provided so as to be rotatable integrally with the rotating shaft 2, and a centrifugal pendulum type vibration absorbing means 9. Yes. The rotating body 1 includes a pair of flange portions 7 and 7 provided so as to be integrally rotatable with the rotating shaft 2, and a cylindrical portion 1a that is disposed between the flange portions 7 and 7 and integrated with each flange portion. Has been. The flange portions 7 and 7 are circular, and are fixed to the rotary shaft 2 so that the centers thereof coincide with the rotation center of the rotary shaft 2. The flywheel 4 has a disk shape, and a central portion thereof is fixed to one end portion of the rotating shaft 2. The rotary shaft 2 is rotatably supported by a base portion such as a frame (not shown) via a bearing (not shown).
[0023]
The drive transmission system 62 is fixed to the drive shaft 8 of the electric motor 5, and is fixed to the drive gear 6 that can rotate integrally with the drive shaft 8, and the rotary shaft 2 positioned between the flywheel 4 and the flange portion 7. The final stage gear 3 is provided. The drive gear 6 and the final gear 3 are mounted on each shaft so as to mesh with each other.
[0024]
In the rotary drive device, when the electric motor 5 is energized and driven, the drive shaft 8 rotates to rotate the rotary shaft 2 via the drive gear 6 and the final gear 3, and together with the rotary shaft 2, the rotary body 1 and The flywheel 4 and the centrifugal pendulum type vibration absorbing means 9 rotate.
[0025]
The rotational drive device having such a configuration has a plurality of vibration components that change in accordance with the rotational speed. For example, vibration components such as the rotation frequency of the electric motor 5, the rotation frequency of the drive gear 6 and the final gear 3 of the drive transmission system 62, and the rotation frequency of the rotation shaft 2 are transmitted to the rotation body 1 and the surface of the rotation body itself. Affects speed fluctuation.
[0026]
Therefore, in this embodiment, the centrifugal pendulum type vibration absorbing means 9 is provided on the rotating system, that is, the rotating shaft 2 between the flywheel 4 and the final gear 3 so as to reduce the influence of speed fluctuation. In this embodiment, a salomon vibration absorber is used as the centrifugal pendulum vibration absorber 9.
[0027]
The centrifugal pendulum type vibration absorber, which is the basis of the Salomon vibration absorber, will be described using the model shown in FIG. This vibration absorber is formed by a pendulum 290 attached to a rotating member 220 integral with the rotating shaft 200. This pendulum 190 can vibrate in the field of centrifugal force generated there. The mass of the pendulum 290 is m, the rotational speed of the rotary shaft 200 is Ω, R is from the center of the rotary shaft 200 to the swing center of the pendulum 290, l is from the swing center to the center of the pendulum 290, and R >> l. When the pendulum mass shown in FIG.₂The centrifugal force acting on₂RΩ²It is. Therefore, assuming that the force P for returning the pendulum 290 to its radial position is smaller than that of the pendulum 290, the following equation (1) is obtained.
P = m₂RΩ²sinθ ≒ m₂RΩ²θ (1)
However, since the change in mass corresponding to the force P is lθ, the apparent spring constant of the pendulum 290 in the centrifugal force field is expressed by the following equation (2):
c₁₂= M₂RΩ²/ L (2)
The natural frequency is obtained by the following equation (3).
ω_{twenty one}= √ {(m₂RΩ²/ L) (l / m₂)} (3)
As described above, the natural frequency of the centrifugal pendulum absorber is not constant and varies depending on the rotational speed Ω of the rotating shaft 200. Therefore, if the disturbance frequency is proportional to the rotational speed Ω, the centrifugal pendulum absorber is kept in synchronization with the disturbance frequency.
[0028]
The centrifugal pendulum type vibration absorbing means 9 according to the present invention utilizes the above principle. The centrifugal pendulum type vibration absorbing means 9 is provided with a circular rotating member 22 formed with a plurality of holes 28... On the rotating shaft 2, and a metal pin 19. It is a fitted Salomon vibration absorber. As shown in FIG. 2, the plurality of holes 28... Penetrate the rotating member 22 in the axial direction, and as shown in FIG. As shown in FIG. 4, the plurality of holes 28... Are centered on the same distance (radius R) from the rotational center O of the rotating member 22.₁And each radius R as shown in FIG.₁Are equal and each center O around the center of rotation O₁It arrange | positions so that the angle (alpha) between may become equal. As shown in FIG. 6, a through hole for inserting the rotating shaft 2 is formed at the center of the rotating member 22. That is, the rotation center of the rotation member 22 becomes the rotation center O of the rotation shaft 2 by attaching the rotation member 22 to the rotation shaft 2.
[0029]
Each pin 19 has a columnar shape having the same diameter and the same length, and has a length protruding from the end faces 22a and 22b of the rotating member 22 in a state of loosely fitting in each hole 28 as shown in FIG. is doing. As shown in FIG. 5, the radius R of each pin 19₂Is the radius R of each hole 28₁Smaller than its center O₂Is the center O₁It is comprised so that it may be located on the radius l. At both ends of each pin 19, as shown in FIG. 7, a retaining link member 40 that is a member that holds each pin in a loosely fitted state in each hole 28 is mounted.
[0030]
In this embodiment, the rotation shaft 2 is the rotation shaft 200, the pin 19 is the pendulum 290, and the distance R from the rotation center O of the rotation member 22 to the center of the hole 28 is the radius R and the center O in FIG.₁To pin 19 center O₂The distances 1 to 1 correspond to 1 in FIG. That is, the centrifugal pendulum type vibration absorbing means 9 has a radius R of the hole 28.₁And pin radius R₂Difference from (R₁-R₂) Constitutes a centrifugal pendulum with a length equal to.
[0031]
By mounting the centrifugal pendulum type vibration absorbing means 9 having such a configuration on the rotation system of the rotary drive device, the speed fluctuation of the rotating shaft 2 can be suppressed, and the vibration component caused by the speed fluctuation can be reduced. The number of holes 28 formed in the rotating member 22 is not limited, but a larger number is preferable because the vibration absorber itself is less biased with respect to the circumferential direction.
[0032]
In many cases, the rotational drive device has a vibration component proportional to a plurality of rotational speeds. For example, vibrations having various frequencies such as rotational vibrations of the drive motor 5, rotational vibrations of the drive gear 6 and the final gear 3, and rotational vibrations of the rotating body 1 are generated.
In such a case, by providing a plurality of centrifugal pendulum type vibration absorbing means in the rotational drive device, a vibration absorbing effect can be obtained for each vibration frequency, resulting in a device configuration with less vibration.
[0033]
  FigureThe rotational drive device shown in FIG. 8 is obtained by adding a centrifugal pendulum type vibration absorbing means 90 to the rotational drive device shown in FIG. The centrifugal pendulum type vibration absorbing unit 90 includes a rotary member 191 provided with a plurality of holes 28A having a radius different from that of the plurality of holes 28 provided in the centrifugal pendulum type vibration absorbing unit 9 at the same distance from the rotation center O.₁And each radius R₁Are formed so as to be at equal angles from the rotation center O, and the pins 19 are loosely fitted in the respective holes 28A and mounted on the rotary shaft 2. That is, in the rotary drive device shown in FIG. 8, a plurality of centrifugal pendulum type vibration absorbing means 9 and 90 having different vibration absorption characteristics are provided in the same rotating system 60, and the speed fluctuation of the rotating shaft 2 is further suppressed. The vibration component caused by this speed fluctuation can be reduced.
[0034]
  Figure9 is obtained by adding a centrifugal pendulum type vibration absorbing means 190 to the rotation driving device shown in FIG. This centrifugal pendulum type vibration absorbing means 190 is provided with a rotational member 220 mounted on the drive shaft 8 and a plurality of holes 28B provided in the centrifugal pendulum type vibration absorbing means 9 and a plurality of holes 28B having different radii. The shafts 8 are centered at the same distance (radius R) from the rotation center O3, are formed so as to have equal radii R1 and equal angles from the rotation center O3. It is fitted. The radius R2 of each pin 19 is smaller than the radius R1 of each hole 28B, and its center O₂Is the center O₁It is comprised so that it may be located on the radius 1 from (refer FIG. 5). That is, in the rotary drive device shown in FIG. 9, since the centrifugal pendulum type vibration absorbing means 9 and 190 are provided in both the rotary system 60 and the drive system 61, the speed fluctuations of the drive shaft 8 and the rotary shaft 2 are suppressed. Thus, vibration components caused by these two speed fluctuations can be reduced. In the rotary drive device shown in FIG. 9, the centrifugal pendulum type vibration absorbing means 90 and 190 are provided in different systems of the rotary system 60 and the drive system 61, respectively, but only the centrifugal pendulum type vibration absorbing means 90 and 190 are provided only in the drive system 61. The form which mounted | wore one side may be sufficient.
[0035]
  Figure11, a flywheel 4 that is an inertial body itself is configured with a Salomon vibration absorber. As shown in the figure, the flywheel 22 has a bearing flange portion 280 through which the rotary shaft 2 is inserted at the center, and the rotational center of the rotary shaft 2 is attached to the rotary shaft 2 so that the rotational center of the flywheel 22 is its own rotational center. O. The flywheel 4 has a center O at the same distance from the rotation center O in the vicinity of the outer periphery thereof.₁And each radius R₁A plurality of holes 28C are formed and arranged so as to have an equal angle from the rotation center O, and the pins 19 are loosely fitted in the respective holes 28C. Radius R of each pin 19₂Is the radius R of each hole 28B₁Smaller than its center O₂Is positioned on the radius l from the center O1 (see FIG. 5).
[0036]
When the salomon vibration absorber is provided on the flywheel 4 in this way, the flywheel 4 itself becomes a vibration absorber, so that the vibration component caused by the speed fluctuation of the rotating shaft 2 can be reduced. In the case where the flywheel 4 itself is used as a vibration absorber, a configuration in which the flywheel 4 itself is mounted on the rotating shaft 2 may be used, or a configuration in which the centrifugal wheel pendulum vibration absorbing unit 9 is provided may be employed.
[0037]
  FigureReference numeral 12 denotes a Salomon vibration absorber in the final gear 3 itself. As shown in the figure, the final stage gear 3 has a shaft hole 3A through which the rotary shaft 2 is inserted at the center, and when the rotary gear 2 is attached to the rotary shaft 2, the rotation center O of the rotary shaft 2 rotates itself. It becomes the center O. The final stage gear 3 has a center O at the same distance from the rotation center O in the vicinity of its outer periphery.₁And each radius R₁Are equal, and a plurality of holes 28D are formed and arranged at equal angles from the rotation center O, and the pins 19 are loosely fitted in the respective holes 28D. Radius R of each pin 19₂Is the radius R of each hole 28D₁Smaller than its center O₂Is the center O₁It is comprised so that it may be located on the radius 1 from (refer FIG. 5).
[0038]
When the Salomon vibration absorber is provided in the final gear 3 in this way, the final gear 3 itself becomes a vibration absorber, so that the vibration component that causes the speed fluctuation of the rotating body 1 caused by the rotational frequency of the final gear 3 is reduced. can do. In the case where the final gear 3 itself is used as a vibration absorber, it may be configured so as to be mounted alone on the rotating shaft 2 or may be configured in combination with the centrifugal pendulum type vibration absorbing means 9. In this embodiment, the Salomon vibration absorber is provided in the final gear 3, but it may be provided in the drive gear 6 or provided in both gears.
[0039]
  Figure13 shows a configuration of a rotary drive device in which the drive transmission system 162 is constituted by pulleys 70 and 71 provided on the rotary shaft 2 and the drive shaft 8 respectively, and a connecting belt 72 spanned between these pulleys. It is a perspective view. As shown in FIG. 14, the rotary drive device shown in FIG. 14 has a pulley 70 itself configured with a Salomon vibration absorber. As shown in the figure, the pulley 70 has a shaft hole 701 through which the rotation shaft 2 is inserted at the center, and the rotation center O of the rotation shaft 2 is attached to the rotation shaft 2 so that the rotation center O of the pulley 70 is its own rotation center O. It becomes. The pulley 70 has a center O at the same distance from the rotation center O in the vicinity of the outer periphery thereof.₁And each radius R₁Are formed, and a plurality of holes 28E are formed and disposed so as to have an equal angle from the rotation center O, and the pins 19 are loosely fitted in the respective holes 28E. Radius R of each pin 19₂Is the radius R of each hole 28E₁Smaller than its center O₂Is the center O₁It is comprised so that it may be located on the radius 1 from (refer FIG. 5).
[0040]
In this embodiment, the pin 19 has a length that does not protrude from both end faces 70 a and 70 b of the pulley 70. Disc-shaped covers 74 and 75 are mounted on both end faces 70a and 70b as members for holding the pins 19 loosely fitted in the holes 28E so as to close the holes 28E. The ring 40 shown in FIG. Is omitted.
[0041]
When the salomon vibration absorber is provided in the pulley 70 as described above, the pulley 70 serves as a vibration absorber, so that a vibration component proportional to the rotation of the pulley 70 that is a fluctuation in the speed of the rotating body 1 can be reduced. Further, since the holes 28E are closed by the covers 74 and 75, the pins 19 are prevented from falling. The covers 74 and 75 preferably have a shape that does not cause non-uniform inertia in the circumferential direction, and preferably have a disk shape as shown in FIG. When the rotation of the pulley 70 is stopped, the pin 19 located outside the hole 28E due to centrifugal force may drop due to gravity and generate sound. However, by providing the covers 74 and 75, noise leaking to the outside Can be reduced.
[0042]
In the case where the pulley 70 itself is used as a vibration absorber, a configuration in which the pulley 70 itself is mounted on the rotary shaft 2 may be used, or a configuration in which the centrifugal pendulum vibration absorbing means 9 is provided. In this embodiment, the Salomon vibration absorber is provided on the pulley 70, but it may be provided on the pulley 71 or may be provided on both pulleys.
[0043]
Of course, the covers 74 and 75 shown in FIG. 14 may be provided on the rotating member 22, the flywheel 4, and the gears in which the holes for loosely fitting the pins 19 are formed. 19 is used. As shown in FIG. 14, the outer periphery of the metal mass 19A is covered with the elastic member 19B to form the pin 19, so that the generation of sound at the time of dropping can be suppressed and the sound leaking to the outside can be reduced. In order to make the surface of the pin 19 the elastic member 19B, the elastic member 19B may be cylindrical and the mass 19A may be inserted into the inside, or the outer periphery of the mass 19A may be coated with the elastic member 19B. The surface of the pin 19 may be a sound absorbing member instead of the elastic member 19B.
[0044]
  Figure10 is a structure in which two Salomon vibration absorbers are formed on one rotating member to reduce vibration components proportional to a plurality of rotational speeds. The rotating member shown in FIG. 10 is the rotating member 22. The rotating member 22 includes a plurality of holes 28 and a plurality of pins 19 already described, and a center O of the hole 28 from the rotation center O.₁Radius R to_outThe same distance from the center of rotation O on the concentric circles different from (radius R_in) And each radius R_{in - 1}Are provided, and a plurality of holes 138 disposed at equal angles from the rotation center O, and pins 139 as pendulum members that are loosely fitted in the holes 138, respectively. The radius Rin-2 of each pin 139 is equal to the radius R of each hole 138._in-1Has been smaller than. In this embodiment, the radius of each pin 19 is R_out-2The radius of each hole 28 is R_out-1Is displayed.
[0045]
The frequency at which vibration can be reduced is determined by the above equation (3)._out/ (R_out-1-R_out-2) Value and R_in/ (R_in-1-R_in-2) Are configured to have different values, one member can have two vibration absorption functions, and two different frequencies can be reduced in a space-saving manner.
[0046]
In FIG. 10, the hole 138 and the pin 139 are provided in the rotating member 22, but the rotating member 191 shown in FIG. 8, the rotating member 220 shown in FIG. 10, the flywheel 4 shown in FIG. 11, and the final gear shown in FIG. 3 or the drive gear 6 and the pulley 70 or the pulley 71 shown in FIG. Note that the configuration of the pin 19 shown in FIG. 15 may be applied to the pin 139.
[0047]
  NextNext, a mode in which the rotational frequency of the drive motor 5 is focused as a vibration factor affecting the speed fluctuation of the surface of the rotating body 1 will be described. In this embodiment, it is assumed that the rotary drive device provided with the centrifugal pendulum vibration absorbing means 9 shown in FIG. 1 is used as a model.
[0048]
When the rotation frequency of the drive motor 5 is a vibration factor, the vibration can be reduced by making the natural frequency of the centrifugal pendulum type vibration absorbing means 9 coincide with the rotation frequency of the drive motor 5. As shown in FIG. 1, when the centrifugal pendulum type vibration absorbing means 9 is provided on the rotating shaft 2, the rotational angular velocity of the drive motor is expressed as X_motor, The rotational angular velocity of the rotating body 1 is X_drumIn this case, by satisfying the relationship of the following expression (4), the rotational frequency of the drive motor 5 is reduced, and the speed of the surface of the rotating body 1 is stabilized.
X_motor= X_drum√ {R / (R₁-R₂)} (4)
For example, the rotational speed of the drive motor 5 is set to X by the drive transmission system 61._motorAnd X_drumIn the case of a rotary drive device in which the ratio is set to 4: 1,
4 = √ {R / (R₁-R₂)} 16 (R₁-R₂) = R (5)
The relationship of the above formula (5) holds, and R = 32, R that can satisfy this relationship₁= 5, R₂This can be realized by attaching the centrifugal pendulum type vibration absorbing means 9 of = 3. Further, the parameters described above may not be used as long as the relational expression is satisfied.
[0049]
  DrivingWhen a stepping motor is used as the dynamic motor 5, there is a step vibration of the motor as one of vibrations affecting the speed fluctuation of the surface of the rotating body 1. Step vibration is determined by the number of rotations per second of the motor and the number of steps in one revolution of the motor. When the centrifugal pendulum type vibration absorbing means 9 is provided on the rotary shaft 2, the step vibration reducing method is to set the rotational angular velocity of the stepping motor to X_{motor_step}, The step number of the stepping motor is S, and the rotational angular velocity of the rotating body 1 is X_drumIf
    SX_{motor_step}= Xd_rum√ {R / (R₁-R₂)} ... (6)
  By satisfying the relationship of the above equation (6), the step vibration of the stepping motor is reduced, and the speed of the surface of the rotating body 1 is stabilized.
[0050]
  FigureAs shown in FIG. 1, when a gear is used for the drive transmission system 61, one of the vibrations affecting the speed fluctuation of the surface of the rotating body 1 is a gear meshing vibration. This meshing vibration is generated when gear teeth collide with each other when torque is transmitted by the gear, and the frequency at which the vibration is generated is determined by the number of rotations of the gear per second and the number of gear teeth. When the centrifugal pendulum type vibration absorbing means 9 is provided on the rotary shaft 2, the gear meshing vibration is reduced by setting the number of gear teeth to Z and the gear rotation angular velocity to X._gear, The rotational angular velocity of the drive motor 5 is X_moto, The rotational angular velocity of the rotating body 1 is X_drumIf
    ZX_gear= X_drum√ {R / (R₁-R₂)} (7)
  By satisfying the relationship of the above formula (7), the meshing vibration of the gear is reduced, and the speed of the surface of the rotating body 1 is stabilized.
[0051]
  FigureWhen the drive transmission system 162 using the belt 72 and pulleys 71 and 72 as shown in FIG. 13 is used instead of the drive transmission system 62 shown in FIG. 1, it is one of the vibrations that affect the speed fluctuation of the surface of the rotating body 1. There is meshing vibration between the belt 72 and the pulley 71. The meshing vibration is generated when the teeth of the belt 72 and the pulley 71 collide with each other when torque is transmitted to the pulley 71, and the frequency at which the vibration occurs is the number of rotations of the pulley 71 and the number of teeth of the pulley 71 per second. Determined by When the centrifugal pendulum type vibration absorbing means 9 is provided on the rotary shaft 2, the pulley meshing vibration is reduced by the number of teeth of the pulley being P and the rotational angular velocity of the pulley 71 being X._pullley, The rotational angular velocity of the rotating body 2 is X_drumIf
    PX_pullley= X_drum√ {R / (R₁-R₂)} (8)
  By satisfying the relationship of the above equation (8), the meshing vibration of the pulley is reduced, and the speed of the surface of the rotating body 1 is stabilized.
[0052]
Examples of the rotating body that is rotationally driven by the rotational driving apparatus described in each embodiment include a roller member and a belt that convey a recording material, and an image carrier of an image forming apparatus. Examples of the recording material include cards that can record and reproduce information represented by a magnetic card, an IC card, a prepaid card, and the like. When the rotation driving device described in each embodiment is used to rotationally drive such a roller member that conveys cards, fluctuations in the rotation of the roller member can be suppressed, thereby reducing variations in card conveyance. And recording and reproduction of information can be performed satisfactorily.
[0053]
Examples of the recording material include postcards, business cards, envelopes, banknotes, and the like, in addition to paper and OHP sheets used in image forming apparatuses in general. When the rotation driving device described in each embodiment is used to rotationally drive the roller member that conveys these members, the conveyance of the sheet-like member can be stabilized, and various processing for jams and sheet-like members can be favorably performed. It can be carried out.
[0054]
  FigureReference numeral 16 denotes a color copying machine as an image forming apparatus to which the present invention is applied. In FIG. 16, the apparatus main body of the image forming apparatus denoted by reference numeral 10 is slightly to the right of the center in the exterior case 11 and is a drum-shaped photoreceptor (hereinafter referred to as “photoreceptor”) that is an example of a rotating body. 12). Around the photosensitive drum 12, a rotating type developing device 14, an intermediate transfer unit 15, and a cleaning device as developing means are sequentially arranged in the rotational direction (counterclockwise direction) indicated by an arrow from a charger 13 installed thereon. 16, a static eliminator 17 and the like are arranged. Among these, the photosensitive drum 12, the charger 13, the rotary developing device 14, the cleaning device 16, and the static eliminator 17 are detachable from the apparatus main body 10 as one image forming unit 90.
[0055]
On these charger 13, rotary developing device 14, cleaning device 16, and static eliminator 17, an optical writing device as an exposure unit, for example, a laser writing device 18 is installed. The rotary developing device 14 includes developing devices 20A, 20B, 20C, and 20D having developing rollers 21 that store toners of yellow, magenta, cyan, and black, respectively, and rotate around a central axis (not shown). The developing devices 20A, 20B, 20C, and 20D for each color are selectively moved to a developing position that faces the outer periphery of the photosensitive drum 12.
[0056]
In the intermediate transfer unit 15, an endless intermediate transfer member as an image carrier, for example, an intermediate transfer belt 24 is wound around a plurality of rollers 23, and the intermediate transfer belt 24 is brought into contact with the photosensitive drum 12. A transfer device 25 is installed inside the intermediate transfer belt 24, and a transfer device 26 and a cleaning device 27 are installed outside the intermediate transfer belt 24. The cleaning device 27 is provided so as to be able to contact with and separate from the intermediate transfer belt 24.
[0057]
The laser writing device 18 receives an image signal of each color from the image reading device 29 via an image processing unit (not shown), and the laser beam L that is sequentially modulated by the image signal of each color is uniformly charged in the photosensitive drum 12. To expose the photosensitive drum 12 to form an electrostatic latent image on the photosensitive drum 12. The image reading device 29 color-separates and reads the image of the document G set on the document table 30 provided on the upper surface of the apparatus body 10 and converts it into an electrical image signal. The recording material conveyance path 32 conveys the paper P as a sheet-like member from right to left. A registration roller pair 33 is installed in the recording material conveyance path 32 in front of the intermediate transfer unit 15 and the transfer device 26, and a conveyance belt 34, a fixing device 35, and a discharge roller are provided downstream of the intermediate transfer unit 15 and the transfer device 26. 36 is arranged.
[0058]
The apparatus main body 10 is placed on the sheet feeding device 50. A plurality of paper feed cassettes 51 are provided in multiple stages in the paper feed device 50, and any one of the paper feed rollers 52 is selectively driven to feed the paper P from any one of the paper feed cassettes 51. . The sheet P is transported to the recording material transport path 32 through the automatic paper feed path 37 in the apparatus main body 10. A manual feed tray 38 is provided on the right side of the apparatus main body 10 so as to be openable and closable. The paper P inserted from the manual feed tray 38 is conveyed to the recording material conveyance path 32 through a manual paper feed path 39 in the apparatus main body 10. The A paper discharge tray (not shown) is detachably attached to the left side of the apparatus main body 10, and the paper P discharged by the paper discharge roller 36 through the recording material conveyance path 32 is accommodated in the paper discharge tray.
[0059]
In this embodiment, when making a color copy, when the original G is set on the original table 30 and a start switch (not shown) is pressed, the copying operation is started. First, the image reading device 29 separates and reads the image of the document G on the document table 30. At the same time, the paper P is selectively sent out from the paper feeding cassette 51 in the paper feeding device 50 by the paper feeding roller 52, and this paper P hits the registration roller pair 33 through the automatic paper feeding path 37 and the recording material conveyance path 32. Stop.
[0060]
The photosensitive drum 12 rotates counterclockwise, and the intermediate transfer belt 24 rotates clockwise by the rotation of the driving roller 23A among the plurality of rollers 23. The photosensitive drum 12 is uniformly charged by the charger 13 as it rotates, and the laser beam modulated by the first color image signal applied from the image reading device 29 to the laser writing device 18 via the image processing unit. Irradiation from the laser writing device 18 forms an electrostatic latent image.
[0061]
The electrostatic latent image on the photosensitive drum 12 is developed by the first color developing device 20A of the rotary developing device 14 to be a first color image. The first color image on the photosensitive drum 12 is transferred by the transfer device 25. The image is transferred to the intermediate transfer belt 24. The photosensitive drum 12 is cleaned by the cleaning device 16 after the image of the first color is transferred to remove residual toner, and is discharged by the charge eliminator 17.
[0062]
Subsequently, the photosensitive drum 12 is uniformly charged by the charger 13, and laser light modulated by the image signal of the second color applied from the image reading device 29 to the laser writing device 18 through the image processing unit is laser-written. Irradiation from the device 18 forms an electrostatic latent image. The electrostatic latent image on the photosensitive drum 12 is developed by the second color developing device 20B of the rotary developing device 14 to become a second color image, and the second color image on the photosensitive drum 12 is transferred by the transfer device 25. The image is transferred onto the intermediate transfer belt 24 so as to overlap with the first color image. The photosensitive drum 12 is cleaned by the cleaning device 16 after the transfer of the image of the second color, the residual toner is removed, and the charge is removed by the charge eliminator 17.
[0063]
Next, the photosensitive drum 12 is uniformly charged by the charger 13, and laser light modulated by an image signal of the third color applied from the image reading device 29 to the laser writing device 18 through the image processing unit is a laser. Irradiation from the writing device 18 forms an electrostatic latent image. The electrostatic latent image on the photosensitive drum 12 is developed by the third color developing device 20C of the rotary developing device 14 to become a third color image. The third color image on the photosensitive drum 12 is transferred by the transfer device 25. The first color image and the second color image are superimposed and transferred onto the intermediate transfer belt 24. The photosensitive drum 12 is cleaned by the cleaning device 16 after the transfer of the image of the third color to remove the residual toner, and is neutralized by the static eliminator 17.
[0064]
The photosensitive drum 12 is uniformly charged by the charger 13, and the laser beam modulated by the image signal of the fourth color applied from the image reading device 29 to the laser writing device 18 through the image processing unit is applied to the laser writing device 18. To form an electrostatic latent image. The electrostatic latent image on the photosensitive drum 12 is developed by the fourth color developing device 20D of the rotary developing device 14 to become a fourth color image. The fourth color image on the photosensitive drum 12 is transferred by the transfer device 25. A full-color image is formed by transferring the first color image, the second color image, and the third color image on the intermediate transfer belt 24 in an overlapping manner. The photosensitive drum 12 is cleaned by the cleaning device 16 after the transfer of the image of the fourth color to remove the residual toner, and is neutralized by the static eliminator 17.
[0065]
The registration roller pair 33 rotates at the timing to feed the paper P, and the full color image on the intermediate transfer belt 24 is transferred to the paper P by the transfer device 26. The sheet P is conveyed by the conveying belt 34, the full color image is fixed by the fixing device 35, and is discharged to the discharge tray by the discharge roller 36. Further, the intermediate transfer belt 24 is cleaned by the cleaning device 27 after the transfer of the full color image to remove the residual toner.
[0066]
The operation for forming a four-color superimposed image has been described above. In the case of forming a three-color superimposed image, three different single-color images are sequentially formed on the photosensitive drum 12 and transferred onto the intermediate transfer belt 24. After that, when the two-color superimposed image is formed by batch transfer onto the paper P, two different single-color images are sequentially formed on the photosensitive drum 12 and transferred onto the intermediate transfer belt 24 in an overlapping manner. Later, it is transferred to the paper P at once. When a single color image is formed, one single color image is formed on the photosensitive drum 12 and transferred onto the intermediate transfer belt 24 and then transferred onto the paper P.
[0067]
In such a color copying machine, the rotational fluctuations of the photosensitive drum 12 and the intermediate transfer belt 24 that are image carriers greatly affect the quality of the final image. Therefore, the photosensitive drum 12 and the intermediate transfer belt 24 with higher accuracy are used. Rotational drive For this reason, in the color copying machine of this embodiment, at least the photosensitive drum 12 is rotationally driven using any one of the rotational driving devices in the first to eleventh embodiments. In this case, the final gear 3 shown in FIG. 1 is fixed to the rotary shaft 81 that supports the photosensitive drum 12, and the drive gear 6 fixed to the drive shaft 8 of the electric motor 5 is engaged with the gear 3. What is necessary is just to comprise so that the photoreceptor drum 12 may be rotationally driven. The flywheel 4 in FIG. 1 may be attached to the rotating shaft 81 as necessary.
[0068]
When it is necessary to reduce the rotational fluctuation of the intermediate transfer belt 24, the final gear 3 shown in FIG. 1 is attached to the shaft 23B that supports the driving roller 23A among the plurality of rollers 23 around which the intermediate transfer belt 24 is stretched. And the gear 3 is engaged with the drive gear 6 fixed to the drive shaft 8 of the electric motor 5 to rotate the intermediate transfer belt 24. What is necessary is just to mount the flywheel 4 to the rotating shaft 23B as needed.
[0069]
In this embodiment, the drum-shaped photoconductor 12 is exemplified as the image carrier, but a belt-shaped photoconductor may be used. In the present embodiment, the image forming apparatus including one photosensitive drum is illustrated. However, it goes without saying that the rotation driving device may be applied to an image forming apparatus in which a plurality of photosensitive drums are arranged in the conveyance direction of the recording paper P. Absent.
[0070]
【The invention's effect】
  BookAccording to the invention, since the centrifugal pendulum type vibration absorbing means is provided to support the rotating body and is driven to rotate by the driving system, vibration generated in the rotating system is reduced, and the rotating speed of the rotating body is stabilized.
[0071]
  BookAccording to the invention, the rotating member in which a plurality of holes are formed is provided on the rotating shaft that can rotate integrally with the rotating body, and the plurality of holes are centered at the same distance from the rotation center of the rotating member, and the respective radii are Since the centrifugal pendulum-type vibration absorbing means is configured by arranging the pendulum members loosely in the holes at equal angles from the center of rotation, the frequency of vibration absorption by the centrifugal pendulum-type vibration absorbing means according to the rotational speed The components fluctuate in proportion, and the vibration generated in the rotating system is reduced and the rotation speed of the rotating body is stabilized.
[0076]
  BookAccording to the invention, the rotating partMaterialA plurality of holes are formed on concentric circles different from the radius from the center of rotation to the center of the hole at the same distance from the center of rotation of each member so that the respective radii are equal and at equal angles from the center of rotation. Since the pendulum member is formed and arranged and loosely fitted in each hole, a single member can provide a vibration absorbing effect for multiple frequencies, saving space compared to the case where a plurality of centrifugal pendulum type vibration absorbing means are provided. Cost reduction can be achieved.
[0077]
  BookAccording to the invention, each pendulum member loosely fitted into the hole and / or hole is held in the hole and / or hole loosely by the holding member, so that the pendulum member can be prevented from falling and absorbing. The hand effect is stable and the rotational speed of the rotating body is more stable. In the case where the holding member is a hole and / or a cover that covers the hole, leakage of sound that occurs with the movement of the pendulum member can be suppressed, leading to a reduction in noise of the apparatus.
[0078]
  BookAccording to the invention, since the surface of the pendulum member is an elastic member, the sound generated with the movement of the pendulum member is reduced, leading to a reduction in noise of the apparatus.
[0084]
  According to the present invention, the aboveSince the image carrier is rotated by the rotation driving device, the rotational vibration to the image carrier is effectively reduced, and the image quality can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a configuration of a rotary drive device including a centrifugal pendulum type vibration absorbing unit according to a first embodiment.
FIG. 2 is a partial cross-sectional view showing a configuration of a rotary drive device and a centrifugal pendulum type vibration absorbing means.
FIG. 3 is a model diagram for explaining the principle of a centrifugal pendulum type vibration absorbing means.
FIG. 4 is an enlarged view showing a configuration of a centrifugal pendulum type vibration absorbing means.
FIG. 5 is an enlarged view of a broken line ◯ portion in FIG. 4;
FIG. 6 is a perspective view of the centrifugal pendulum type vibration absorbing unit alone according to the first embodiment.
FIG. 7 is an enlarged sectional view showing a holding state of the pendulum member.
FIG. 8 is a partial cross-sectional view showing a configuration of a rotary drive device provided with two centrifugal pendulum type vibration absorbing means according to a second embodiment in the same system.
FIG. 9 is a partial cross-sectional view showing a configuration of a rotary drive device provided with a centrifugal pendulum type vibration absorbing means according to a third embodiment in a different system.
FIG. 10 is a perspective view showing a configuration of a centrifugal pendulum type vibration absorbing means having a plurality of different vibration absorption characteristics according to a seventh embodiment.
FIG. 11 is a partial cross-sectional view showing a configuration of a rotary drive device having a centrifugal pendulum type vibration absorbing means integrated with an inertial body according to a fourth embodiment.
FIG. 12 is a perspective view showing a configuration of a centrifugal pendulum type vibration absorbing unit integrated with a gear according to a fifth embodiment.
FIG. 13 is a partial cross-sectional view showing a configuration of a rotary drive device having centrifugal pendulum type vibration absorbing means integrated with a pulley according to a sixth embodiment.
FIG. 14 is an enlarged cross-sectional view showing a configuration of a centrifugal pendulum type vibration absorber integrated with a pulley.
FIG. 15 is a partially broken enlarged sectional view showing a configuration of a pendulum member.
FIG. 16 is an overall configuration diagram illustrating an embodiment of an image forming apparatus having a rotation driving device.
[Explanation of symbols]
1 Rotating body
2 Rotating shaft
3,6 Multiple gears
4 Inertial body
5 Rotation drive source
9, 90, 190 Centrifugal pendulum type vibration absorbing means
12, 24 Image carrier
19 First pendulum member
22,191,220 Rotating member
28, 28A-28E Multiple holes
40 Member to hold
60 Rotation system
61 Drive system
62 Drive transmission system
70, 71 first and second pulleys
72 Connecting belt
74,75 Holding member
138 multiple holes
139 Second pendulum member
α Equal angle from the center of rotation
O Rotation center of rotating member
O₁                           Hole center
O₂                           The center of the first pendulum member
O_Three                           Gear rotation center
R, R_out, R_in              Same distance (radius)
R₁                           Hole radius
R₂                           Radius of the first pendulum member
R_in-1                       Hole radius
R_in-2                       Radius of the second pendulum member

Claims (4)

In a rotary drive device comprising: a rotary system that supports a rotary body; a drive system having a rotary drive source that rotationally drives the rotary system; and a drive transmission system that connects the rotary system and the drive system;
Set the centrifugal pendulum vibration absorbing means at least in the rotation system,
The centrifugal pendulum type vibration absorbing means includes a rotating member provided on a rotating shaft that can rotate integrally with the rotating body, a plurality of holes formed therein, and a first pendulum member that is loosely fitted into the plurality of holes. The plurality of holes are arranged at the same distance from the center of rotation of the rotating member, the radii thereof being equal, and arranged at equal angles from the center of rotation.
The rotating member has a center at the same distance from the rotation center on a concentric circle different from the radius from the rotation center to the center of the hole, and the respective radii are equal and have an equal angle from the rotation center. A rotation driving device having a plurality of holes arranged and a second pendulum member loosely fitted in each hole . The rotary drive device according to claim 1, wherein
A rotary drive device having a member that holds the first pendulum member and / or the second pendulum member in a state of loosely fitting into the hole and / or hole . The rotary drive device according to claim 1 or 2,
A rotary drive device in which the surface of the first and / or second pendulum member is an elastic member . An image forming apparatus that forms an image by rotating an image carrier,
An image forming apparatus comprising the rotation drive device according to claim 1, wherein the image carrier is rotationally driven using any rotation drive device .

Images