JPH0742773A - Damping device of rotating drum - Google Patents

Abstract

PURPOSE:To control any variation in revolution of a rotating drum to be produced in the case where rotational unevenness and disturbing vibration in loath drive source and driving force transmission systems act on this drum, by providing a cling device of this rotating drum in an electrophotographic color printer or the like. CONSTITUTION:Silicone oil 7 is held in a clearance where a side face 1a of a rotating drum 1 and a fixed plate 4 are opposed to each other with two O-rings 10 and 11, thereby having a damper braking function provided therein, while a torsion elastic part 12 made up of reducing its torsional rigidity is installed at the driving torque impressing side of a tuning shaft 2. High frequency rotational unevenness or the like produced in both drive source and driving force transmission systems is damped by a mechanical buffer function of the torsion elastic part 12, whereby a constant speed rotational characteristic of this rotating drum 1 is improved in addition to the damper braking function. Especially, since it is applied to a rotating drum mechanism of a color printer, the promotion of high quality in a record image will cane to fruition in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary drum braking device, and is applied to a rotary drum mechanism in an electrophotographic color printer or the like. The present invention relates to a braking device that suppresses fluctuations in rotational speed that occur when mechanical vibration acts and maintains constant-speed rotation of a rotating drum.

[0002]

2. Description of the Related Art Conventionally, a structure as shown in FIG. 6 has been adopted in an electrophotographic color printer, and a rotary drum 51 around which a photosensitive paper is wound is mounted on a stepping motor via a speed reducing mechanism 52 such as a harmonic gear. It is rotationally driven by (hereinafter referred to as “STEP motor”) 53, and an electrophotographic printing process is executed in the orbiting process.

Then, the photosensitive paper 54a supplied from the photosensitive paper roll 54 is wound around the rotating drum 51 in close contact, and the surface of the photosensitive paper 54a is charged by the corona discharge of the charger 55 in the course of its winding. Laser emitting section 56
While scanning the laser beam output from the polygon mirror 57 through the optical system (lens, mirror) 58, the photosensitive paper 54a
To form an electrostatic latent image by exposing the surface of the photosensitive paper 54a with a pre-wetting device 59, and then develop with toner developer 60, and squeeze 61 to roughly remove the toner developer 60. After that, the surface of the photosensitive paper 54a is dried by the heater 62 to fix the dye of the toner, and the charge removal lamp 63
Then, a series of processes for removing the charged electric charge is executed. In a color printer, the above process is repeated for each toner developer of yellow (Y) → magenta (M) → cyan (C) → black (B), and finally a color image is printed on the photosensitive material. The paper 54a will be ejected.

In the above color printer, in order to improve the quality of the color image, it is an essential condition that the rotary drum 51 can be rotated with high accuracy. In that case, in the development by the electrophotographic method, the development time is mainly determined by the power of the laser and the scanning resolution, and when the semiconductor laser is used as the light source, the rotating drum 51 cannot be rotated at a very high speed.
The rotation is controlled for several tens of seconds per one rotation.

For this reason, in this type of color printer, the STEP motor 53 having excellent controllability is used as a drive source, and the reduction mechanism 52 has a large reduction ratio to ensure effective utilization of the drive torque and high resolution. Has been realized, and high quality image printing is possible. A timing belt or a gear is used as a driving force transmission mechanism from the STEP motor 53, and the driving system in which the reduction mechanism 52 is interposed is described in the above example, but the STEP motor 53 is rotated depending on the color printer. There is also a method in which the rotary drum 51 is directly connected to the drum 51 and is rotated by microstep drive.

By the way, when the rotation control of the rotary drum 51 is performed by using the STEP motor 53 as a drive source,
Rotational unevenness peculiar to the driving force transmission mechanism including the EP motor 53 and the speed reduction mechanism 52 occurs. In addition, other mechanisms that are driven at the same time also generate mechanical vibrations, and the installation location of the color printer often receives vibrations from the outside. Then, the rotation unevenness and the vibration described above act on the rotating drum 51 in a manner in which they are superposed, and when actually measuring the rotating speed of the rotating drum 51, a minute fluctuation of the rotating speed at a high frequency due to the influence is caused. It is demonstrated that is continuously occurring.

On the other hand, in the electrophotographic color printer, the laser beam is scanned on the assumption that the rotary drum 51 is rotated at a constant speed, and in the color printer having a high resolution, the fluctuation of the rotary speed of the rotary drum 51 is small. However, a fine shade or color shift is generated in the recorded image, resulting in deterioration of the quality of the recorded image. Further, not only in the field of image recording such as a color printer, but also in a device that generally controls a rotating drum with high accuracy at a constant speed, it is often the case that a minute fluctuation in the rotating speed due to various factors must be suppressed. Absent.

Therefore, the inventor of the present application, in the previous patent application (Japanese Patent Application No. 5-47239), states that "the side surface of the rotary drum and the gap between the fixed plate facing the side surface, or the outer periphery of the side surface of the rotary drum. Of the rotating drum, which is characterized in that the viscous fluid is retained in the gap between the surface and the outer peripheral surface of the fixed ring that is fitted onto the outer surface of the fixed drum, and is rotated by the damper function using the shearing force of the viscous fluid. We have succeeded in greatly improving the constant speed rotation characteristics of the rotating drum by a method that suppresses fluctuations in speed.

Specifically, as shown in FIG. 7, a fixed plate fixed to the support frame 3 with respect to the side surface 1a of the rotary drum 1.
4 are opposed to each other, and the rotary shaft 2 of the rotary drum 1 is axially supported by the fixed plate 4 via the radial bearing 5, and two shafts are concentrically formed around the rotary shaft 2 in the gap 6 between the facing surfaces. The ring-shaped grooves 8a, 8b, 9 are formed in the side surface 1a of the rotary drum 1 and the inner side surface 4a of the fixed plate 4 in order to load and hold the O-rings 10, 11 of the stationary ring 4 in a pressed state.
O-rings 10 and 11 that make up a and 9b, and are in the loaded / loaded state
A viscous fluid 7 such as high-viscosity silicone oil is filled in between the O-rings 10 and 11, and the shearing force proportional to the rotation speed of the rotary drum 1 is maintained in the state where the viscous fluid 7 is held between the O-rings 10 and 11. By utilizing the damper function generated, fluctuations in the rotational speed of the high frequency generated in the rotary drum 1 are effectively suppressed.

Further, as shown in FIG. 8, a ring-shaped portion 22 formed on the fixed plate 21 is fitted onto the outer peripheral surface of the side portion of the rotary drum 1 so that the ring-shaped portion 22 of the rotary drum 1 and the above-mentioned ring-shaped portion 22 can be fitted. Two circumferential grooves 23a, 23b, 24a, 2 on the circumferential facing surfaces 23, 24 respectively
4b are formed, and 2 are formed in each circumferential groove 23a, 23b, 24a, 24b.
The O-rings 25 and 26 of the book are fitted to each other, and the above-mentioned circumferential facing surfaces 23,
The same function can be exerted also by a method in which the gap between the O-rings 25 and 26 is filled with the silicone oil 7 while the pressure is applied between 24. still,
In each of the above-mentioned methods, means for increasing the damper characteristics by making the gap in the intervening region of the viscous fluid meander, and means for holding the viscous fluid as a magnetic fluid by an annular magnet can be adopted.

[0011]

However, in order to realize a sufficient braking function in the above-mentioned rotary drum braking device, a method of using highly viscous silicone oil, a method of increasing the effective area of the facing surface, and Although the method of narrowing the gap is effective, a larger rotational driving force is required accordingly. In addition to the normal recording process, it is required to increase the rotation speed in order to improve the time efficiency, but it becomes difficult when a large reverse rotation torque is generated by the damper braking function. Therefore, when the above-mentioned braking device is applied, it is necessary to use a drive source having a high driving ability in any case, and it is also necessary to use parts having a high load tolerance for the drive force transmission system and the speed reduction mechanism. As a result, it becomes a problem in developing a small and inexpensive device.

On the other hand, since it is the highest priority to achieve high image quality in a color printer, even if a drive source and a transmission / deceleration mechanism with high efficiency and high load tolerance are used, In many cases, it is required to further improve the uneven rotation.

Therefore, the present invention provides a device provided with a braking function for attenuating the rotation unevenness of the high frequency component by using the conventional braking device together and paying attention to the rotating shaft portion, and solves the above problems. At the same time, it was created for the purpose of realizing a printer capable of obtaining higher quality recorded images.

[0014]

According to the present invention, there is provided a gap between a side surface of a rotary drum and a fixed plate facing the side surface, or a side outer peripheral surface of the rotary drum and a fixed ring externally fitted to the side outer peripheral surface. In a rotary drum mechanism in which a viscous fluid is retained in a body gap, the torsional rigidity of a part of a driving force transmission shaft for the rotating drum or a connecting shaft portion of the driving force transmission shaft and a rotary drive system is smaller than that of other portions. The present invention relates to a braking device for a rotating drum.

[0015]

According to the present invention, the torsional rigidity is set small in a part of the driving force transmitting shaft or in the connecting shaft portion of the driving force transmitting shaft and the rotary drive system, so that the mechanical buffer function of the portion is improved. Based on this, it is possible to absorb the rotation unevenness in the high frequency range. Further, the buffer function merely has a buffering function, and does not increase the load torque unlike the damper function by the viscous fluid.

Therefore, it is possible to preliminarily attenuate or remove the fluctuation component of the high frequency contained in the rotation torque acting on the rotary drum from the drive source, and in addition to the damper function by viscous fluid, Further, it is possible to realize excellent constant speed rotation of the rotating drum.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a braking device for a rotary drum of the present invention will be described in detail below with reference to FIGS. First, Fig. 1
FIG. 8 is a cross-sectional view showing a rotary drum mechanism of the color printer according to the embodiment, and the structure of the support mechanism portion thereof is the same as the structure of FIG. 7 which is a conventional technique. That is, 1 is a rotary drum, 2 is a rotary shaft fixed to the rotary drum 1, 3 is a support frame,
4 is a fixed plate attached to the support frame 3,
Reference numeral 2 is pivotally supported in a hole of a fixed plate 4 via a radial bearing 5. Further, the side surface 1a of the rotary drum 1 and the inner side surface 4a of the fixed plate 4 are opposed to each other, and the silicone oil 7 having a large viscosity coefficient is interposed in the gap 6 between the opposed surfaces 1a and 4a. And as a means for holding the silicone oil 7,
Two annular grooves 8a, 8b, 9a, 9b are formed facing each other on a concentric circle centered on the rotation axis 2 in each of the facing surfaces 1a, 4a, and two annular grooves 8a, 8b, 9a, 9b are provided. The O-rings 10 and 11 are fitted, and the O-rings 10 and 11 are pressed between the facing surfaces 1a and 4a, and the silicone oil 7 is filled between the O-rings 10 and 11 in the gap 6. It has been configured.

Therefore, the silicon oil 7 is filled in a thin annular disk space in a sealed state, the flat area of the space is S, the viscosity coefficient of the silicon oil 7 is μ, and the rotary drum is
When the rotation speed of 1 is U and the space of the gap 6 is Y, the shearing force of the silicone oil 7 against the rotating drum 1 is T = S ・ μ ・ (U / Y)
And exerting a damper function for the rotary drum 1, it is possible to prevent minute fluctuations in the rotation speed of the rotary drum 1 due to uneven rotation of the drive source / driving force transmission system or disturbance vibration.

Further, in the rotating state of the rotary drum 1,
The O-rings 10 and 11 are concentrically attached to the rotary shaft 2 and slide in a manner that a lubricating layer of silicon oil 7 is formed between the O-rings 10 and 11 and the annular grooves 8a, 8b, 9a and 9b. A large load torque is not generated due to the pressure-holding / holding structure of the rings 10 and 11.

By the way, in the above structure, T = S · μ ·
As shown in the formula (U / Y), the flat area of the annular disc space is increased, the viscosity coefficient of the silicone oil 7 is increased, and the spacing of the gap 6 is decreased, the above braking performance is improved. However, the drive torque for the rotary drum 1 must be increased accordingly. In particular, in an operation process other than the process operation state of the color printer, it is necessary to increase the rotation speed of the rotary drum 1 to improve time efficiency.
In order to generate a reverse torque proportional to the rotation speed while always acting during 1 rotation, use a STEP motor that is a drive source with a large drive torque, or increase the reduction ratio of the reduction mechanism to increase the STEP motor speed. It is necessary to take measures such as increasing the rotation speed. Therefore, if a measure is taken to suppress the rotation unevenness even if the damper braking performance is lowered to some extent, the reverse torque can be reduced to increase the rotation speed of the rotary drum 1 to the required speed. It becomes possible, and it is not necessary to take the above measures. Further, if another rotation unevenness suppressing unit is provided while maintaining the damper braking performance, it is possible to obtain a higher quality printed image.

Therefore, in this embodiment, as another rotation unevenness suppressing means, as shown in FIG. 1, a torsion elastic portion 12 having a reduced shaft diameter is formed on a part of the driving force transmitting side of the rotary shaft 2. In this configuration, a twist angle proportional to the load torque is intentionally generated. That is, the torsional torque for the round bar
The relationship between (T) and the relative twist angle (θ) at both ends of the member is T = G * Ip * θ / Lp (where G: lateral elastic coefficient of member, Ip: second polar moment of area of member, lp: indicated by member length), also in round bar ^{Ip = π * D 4/32} ( where, D: although given as the diameter of the member), torsion elastic part
By making the diameter D at 12 small, the torsional rigidity (G * Ip) at that portion is made small. The torsional rigidity (G * Ip) of the torsional elastic portion 12 is set to be much smaller than the torsional rigidity of other elements of the rotary shaft 2 and each element of the rotary drive system. Elements other than 12 can be assumed to be completely rigid with respect to driving torque.

Further, the torsion elastic portion 12 does not necessarily have to be formed on the rotary shaft 2, and as shown in FIG. 2A, a connecting shaft portion which is a connecting component of the rotary shaft 2 and the rotary drive system. 13 may be formed. Further, in order to reduce the torsional rigidity (G * Ip), a method of reducing the lateral elastic modulus (G) of the member can be adopted, as shown in FIG. 2 (B). As described above, when the rotating shaft 2 is made of steel or stainless steel, the member of the connecting shaft portion 14 may be made of aluminum or synthetic resin, and the shaft diameter of the connecting shaft portion 14 may be designed to be equal to that of the rotating shaft 2. It is possible.

Next, the principle of suppressing the rotation unevenness of the rotary drum 1 when the torsion elastic portion 12 is formed on the rotary shaft 2 or when the connecting shaft portions 13 and 14 are applied will be described. First, if the mechanical system of the rotary drum mechanism of FIG. 1 is converted into an electrical system, it can be replaced with an equivalent circuit as shown in FIG. In that case, with C as the capacity, 1 / C is the torsional rigidity (G * Ip) of the torsional elastic portion 12, the reactance L is the rotational moment of inertia of the rotary drum 1, and the resistance R is the braking torque based on the damper braking function. , The voltage Vo is the drive torque applied to the rotary shaft 2, the current Io is the rotational angular velocity of the rotary shaft 2 on the drive torque application side, and the current Ia is the rotary drum 1.
Current Ib corresponds to the torsional angular velocity of the torsional elastic portion 12, and the cause of the uneven rotation of the rotary drum 1 is due to the STEP motor or the reduction mechanism that is the drive source. It can be assumed that the DC output of the current circuit 15 contains the weak AC component of the AC generation circuit 16.

At this point, the STEP motor is activated and the rotary shaft 2
When a drive torque is applied to (when the switch 17 is turned on), a transient twist occurs in the twist elastic portion 12 (charge is charged to C), but when the steady state is entered, the rotating drum 1 The rotary shaft 2 rotates at an angular velocity equivalent to the rotational angular velocity on the drive torque application side (the current Ia flowing in the L-R series circuit becomes constant, and Ia = Io).

If the rotational angular velocity on the drive torque application side of the rotary shaft 2 fluctuates after the shift to the steady state, Io can be regarded as an alternating current for analysis, and the fluctuation component is the rotational component. The rotational angular velocity (Ia) of the drum 1 and the torsional angular velocity (Ib) of the torsion elastic portion 12 are distributed. In this state, the condition of Io = Ia + Ib ... Vo = (R + ωjL) * Ia = Ib / (ωjC) (where ω is the angular velocity of the fluctuation component on the drive torque applying side of the rotating shaft 2) is satisfied, and Eliminating Ib with and yields: Ia = Io / [ωjC (R + ωjL) +1] = Io / (1-ω * ωjLC + ωjCR) ...

Therefore, as is clear from the equation, Ia
Has a tendency to be attenuated in inverse proportion to the square of ω, and the coefficient is given by LC. Therefore, when ω is large, Ia can be greatly attenuated as the capacitance value C increases. In other words, when the variation of the torque applied to the rotating shaft 2 occurs at a high frequency, if the torsional rigidity (G * Ip) of the torsional elastic portion 12 corresponding to 1 / C is reduced, Rotating drum with mechanical buffer function
The fluctuation component of the rotational angular velocity of 1 can be greatly attenuated.

By the way, as described above, in this embodiment, the Ip in the torsion elastic portion 12 [FIG. 1] and the connecting shaft portion 13 [FIG. 2 (A)] is increased.
By making the value smaller, the torsional rigidity (G * Ip) of that part is set smaller. Further, in the connecting shaft portion 14 [FIG. 2 (B)], the torsional rigidity (G * Ip) of the portion can be set to be small by reducing G from the viewpoint of the material. Therefore, the fluctuation of the torque applied to the rotary shaft 2 generated by the STEP motor or the speed reduction mechanism is damped by the above-described principle based on the interposition of the torsion elastic portion 12 and the connecting shaft portions 13 and 14, and the damper braking by the silicon oil 7 is performed. In addition to the function, it becomes possible to more effectively suppress the uneven rotation of the rotary drum 1. Also,
Even when the damper braking performance of the silicon oil 7 is lowered to some extent and the rotation speed of the rotating drum 1 is increased during operations other than the recording process operation, the function of suppressing uneven rotation can be complemented by the mechanical buffer function.
It is possible to ensure high-quality image printing without providing the driving system with a large driving force.

As an experimental example, the rotating drum supporting mechanism shown in FIG. 1 was used, and a torque was supplied to the rotating shaft 2 by a STEP motor through a speed reducing mechanism, and the torsion elastic portion 12 was not provided. It was decided to measure and compare the rotation speed of the rotating drum 1 in the cases. In this experiment, the STEP motor was rotated by microstep drive (1/256),
1/25 using a two-stage timing belt for the reduction mechanism
The rotation speed of the rotating drum 1 is 1 revolution /
The measurement data of the rotation unevenness was obtained at 60 seconds.
Further, since a resonance system is configured depending on the setting of the torsional rigidity (G * Ip) of the torsional elastic portion 12 with respect to the rotational moment of inertia of the rotary drum 1, the cross-sectional diameter of the torsional elastic portion 12 is defined by the above formula. Is selected so that ω >> √ (1 / LC).

As a result, when the torsion elastic portion 12 is not provided, measurement data relating to the fluctuation of the rotational angular velocity as shown in FIG. 4 is obtained, and when the torsion elastic portion 12 is provided, it is shown in FIG. Such measurement data was obtained. However, in this measurement result, the variation of the rotational angular velocity is shown with respect to the time along the horizontal axis [scale is every 5 seconds] and the rotational angular velocity is along the vertical axis [scale is every 0.077 (° / sec)]. As is clear from the comparison of the drawings, the fluctuation in the rotation speed is attenuated by about 40% on average in the case where the torsion elastic portion 12 is provided, compared with the case where the torsion elastic portion 12 is not provided. It can be understood that the occurrence of is greatly suppressed.

As described above, in this embodiment, the torsional elastic portion 12 [FIG. 1] and the connecting shaft portions 13, 1 are attached to the support mechanism portion of the rotary drum of FIG. 7.
The case where 4 [Fig. 2] is applied has been described, but naturally, Fig. 8 is used.
Similar results can be obtained by applying it to the supporting mechanism portion of the rotating drum shown in FIG. In addition, as a method of supporting the rotating drum, there is a method in which the rotating drum is attached to a fixed shaft via a radial bearing, and the rotating drum is directly rotated by a gear transmission mechanism or a timing belt. The same effect can be obtained by interposing a portion having a small torsional rigidity (G * Ip) on the driving force transmission shaft incorporated in these mechanisms.

According to the above equation, the damping efficiency of the rotation unevenness can be increased by increasing the value of LC.
If the torsional rigidity (G * Ip) of the torsional elastic portion 12 and the connecting shaft portions 13 and 14 corresponding to / C is reduced, bending deformation tends to occur in that portion, and conversely, uneven feeding due to load fluctuation on the rotating drum 1 side. And position reproducibility may be deteriorated. Therefore, the torsional rigidity (G * Ip) needs to be set in consideration of the balance with the rotational inertia moment (L) of the rotary drum 1 and the damper braking performance (R).

[0032]

The braking device for a rotary drum according to the present invention has the following effects due to the above-mentioned configuration. In contrast to the conventional rotary drum mechanism with a damper braking function, the shaft of the drive force transmission system to the rotary drum such as the rotary shaft is provided with a portion with a small torsional rigidity, and in addition to the damper braking function, a mechanical Since the rotation unevenness is attenuated by the buffer function, the constant speed rotation characteristic of the rotary drum can be further improved. In particular, by applying it to the rotary drum mechanism of an electrophotographic color printer, fine light and shade and color misregistration are eliminated, and high quality of a recorded image is realized. In addition, the conventional damper braking function is an obstacle to increasing the rotation speed in order to generate the reverse torque proportional to the rotation speed of the rotary drum. However, by using the mechanical buffer function of the present invention together, the damper braking function It becomes possible to keep the uneven rotation small while reducing the performance and increasing the rotation speed. This eliminates the need to use a drive source with a high drive capacity and parts with a high load tolerance for the drive force transmission system and reduction mechanism, and also allows a wider selection range for parts such as timing belts. Therefore, there is an advantage that a small-sized and inexpensive rotary drum driving device can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing a rotary drum mechanism of a color printer to which a rotary drum braking device of the present invention is applied.

FIG. 2 is a side view of a partial cross-section of a supporting mechanism of a rotating drum and a connecting shaft portion [(A) shows a case where a second polar moment of area is small, (B) shows a case where a lateral elastic modulus (G) of a member is small. ].

FIG. 3 is an equivalent circuit diagram in which a mechanical system of a rotary drum mechanism is converted into an electrical system.

FIG. 4 is a graph showing a change in rotational angular velocity in the case where no torsion elastic portion is provided in an experimental example.

FIG. 5 is a graph showing fluctuations in rotational angular velocity when a torsion elastic portion is provided in an experimental example.

FIG. 6 is a schematic configuration diagram centering on a rotating drum in an electrophotographic color printer.

FIG. 7 is a sectional view of a rotary drum mechanism to which a conventional braking device is applied.

FIG. 8 is a sectional view of a rotary drum mechanism to which a conventional braking device is applied.

[Explanation of symbols]

1, 51 ... Rotating drum, 1a, 4a, 23, 24 ... Opposing surfaces (1a is a side surface of the rotating drum 1, 23 is a side outer peripheral surface of the rotating drum 1), 2 ... Rotating shaft, 3 ... Support frame, 4, 21 ... Fixing plate, 5 ... Radial bearing, 6 ... Gap, 7 ... Silicon oil (viscous fluid), 8a, 8
b, 9a, 9b ... Annular groove, 10, 11, 25, 26 ... O-ring, 12 ... Torsional elastic part, 13, 14 ... Connection shaft part, 15 ... Constant current circuit, 16 ... AC generation circuit, 17 ... Switch, 22 ... Ring part of fixed plate, 23a, 23
b, 24a, 24b ... Circumferential groove, 51 ... Rotating drum, 52 ... Reduction mechanism, 53 ... STEP motor (stepping motor), 54 ... Photosensitive paper roll, 54a ... Photosensitive paper, 55 ... Charger, 56 ... Laser emitting section , 57 ... Polygon mirror, 58 ... Optical system, 59 ... Pre-wet device, 60 ... Toner developing solution, 61 ... Squeeze, 62 ... Heater, 63 ... Static elimination lamp, C ... Capacity, Io, Ia, Ib ... Current,
L ... Reactance, R ... Resistance, Vo ... Voltage.

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[Procedure amendment]

[Submission date] September 22, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

Next, the principle of suppressing the rotation unevenness of the rotary drum 1 when the torsion elastic portion 12 is formed on the rotary shaft 2 or when the connecting shaft portions 13 and 14 are applied will be described. First, if the mechanical system of the rotary drum mechanism of FIG. 1 is converted into an electrical system, it can be replaced with an equivalent circuit as shown in FIG. In that case, with C as the capacity, 1 / C is the torsional rigidity (G * Ip) of the torsional elastic portion 12, the reactance L is the rotational moment of inertia of the rotary drum 1, and the resistance R is the coefficient of braking based on the damper braking function. The voltage Vo is the drive torque applied to the rotary shaft 2, the current Io is the rotational angular velocity of the rotary shaft 2 on the drive torque application side, and the current Ia is the rotary drum 1.
Current Ib corresponds to the torsional angular velocity of the torsional elastic portion 12, and the cause of the uneven rotation of the rotary drum 1 is due to the STEP motor or the reduction mechanism that is the drive source. It can be assumed that the DC output of the current circuit 15 contains the weak AC component of the AC generation circuit 16.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

If the rotational angular velocity on the drive torque application side of the rotary shaft 2 fluctuates after the shift to the steady state, Io can be regarded as an alternating current for analysis, and the fluctuation component is the rotational component. The rotational angular velocity (Ia) of the drum 1 and the torsional angular velocity (Ib) of the torsion elastic portion 12 are distributed. In this state, the condition of Io = Ia + Ib ... Vo = (R + ωjL) * Ia = Ib / (ωjC) (where ω is the angular velocity of the fluctuation component on the drive torque applying side of the rotating shaft 2) is satisfied, and Eliminating Ib with and yields: Ia = Io / [ωjC (R + ωjL) +1] = Io / (1-ω * ωL C + ωjCR) ...

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

As an experimental example, the rotating drum supporting mechanism shown in FIG. 1 was used, and a torque was supplied to the rotating shaft 2 by a STEP motor through a speed reducing mechanism, and the torsion elastic portion 12 was not provided. It was decided to measure and compare the rotation speed of the rotating drum 1 in the cases. In this experiment, the STEP motor was rotated by microstep drive (1/256),
1/25 using a two-stage timing belt for the reduction mechanism
The rotation speed of the rotating drum 1 is 1 revolution /
The measurement data of the rotation unevenness was obtained at 60 seconds.
Also, the rotational moment of inertia of the rotary drum 1 and the torsional elastic portion 1
For two of the torsional rigidity (G * Ip), depending on how the setting of the damping factor R for resonance system from being configured, R represents ten
It is set to have a sufficient braking effect.

Claims (1)

[Claims] 1. A viscous fluid is retained in a gap between a side surface of a rotary drum and a fixed plate facing the side surface, or in a clearance between a side outer peripheral surface of a rotary drum and a fixed ring body externally fitted on the side outer peripheral surface. In the rotating drum mechanism described above, the torsional rigidity of a part of the driving force transmitting shaft for the rotating drum or a connecting shaft portion of the driving force transmitting shaft and the rotary drive system is made smaller than other portions. Braking system.