JP2007212806A - Rotary drive device, apparatus with rotary drive device as driving source and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary drive device where the body to be rotated is made removable from a driving source, and, when the body to be rotated is mounted on the side of the driving source, the mounting can be performed in a state where, regarding the axis of rotation in the driving source and the axis of rotation in the body to be rotated, an axial center deviation and declination are minute, and driving transmission at high precision is made possible. <P>SOLUTION: An output shaft 11 is inserted into a cylindrical member 13a. A slight gap is provided between bearings 11a, 11b to form into the bearings of the output shaft 11. The gap generates a deviation in the axes of rotation between an output gear 16 and a fixed gear 14, but, an epicyclic gear has an action of adjusting the axes of rotation between the output gear 16 and the fixed gear 14 simultaneously with driving force transmission. In the case three epicyclic gears are present, while the output gear 16 is supported at three points in accordance with the position of the fixed gear 14, an action of deviating the position of the output gear 16 to a direction for adjusting the axes of rotation is brought out for transmitting driving force. In this way, the high precision rotation of the output shaft can be achieved by adjusting the axes of rotation even if the slight gap is present. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rotation driving device, and more particularly to a rotation driving device for driving a photosensitive drum, a transfer belt driving roller, a paper conveying roller, and the like of an image forming apparatus.

  In an image forming apparatus, there is a demand for stability of rotational body drive speed. That is, a rotating body in the image forming apparatus, for example, a drum-shaped photoconductor, a roller member that drives and conveys a transfer belt, a roller member that conveys a transfer material, and the like are required to have high rotation accuracy (stability of rotational angular velocity). The This is because these fluctuations in the rotational angular velocity cause errors in the image forming position on the photosensitive member, intermediate transfer member, and transfer material, and cause deterioration of the output image.

  Further, there is a demand for downsizing the image forming apparatus. In recent years, image forming apparatuses are not only ink-jet type but also electrophotographic type apparatuses are often installed on personal desks, and downsizing of the apparatus is required. In such an image forming apparatus, it is necessary not only to reduce the size of components but also to reduce the size of the rotating body drive mechanism in the image forming apparatus.

  Further, the image forming apparatus has a demand for maintenance. That is, the photoconductor, transfer belt, transfer material conveyance belt, and transfer material conveyance roller used in the image forming apparatus are composed of all or a part of an elastic body, and the life (durability) of the apparatus body There are many short ones. These parts alone or a unit including the parts must be detachable and replaceable from the apparatus main body to realize maintainability.

  Here, an outline of the rotating body driving device will be described. The structure of the rotating body driving device includes a motor that is a driving source, a speed reducing device that reduces the rotational speed of the motor to a desired speed range of the rotating body (generally a speed reducing device that uses a toothed wheel train), Coupling connected to the rotation axis of the body, and the rotated body. With such an apparatus configuration, a configuration that satisfies the above three requirements (rotation accuracy, miniaturization, maintenance) is required.

  A direct drive motor is a conventional example that achieves high-precision rotation and miniaturization. That is, as a configuration for realizing a reduction in size of the drive device, there is a removal of the reduction gear. This may be any configuration as long as the motor has a desired torque within a desired speed range of the rotated body and rotates with high accuracy. As such a motor, there is a motor disclosed in Patent Document 1. The motor proposed in Patent Document 1 is an outer rotor type equipped with a rotation sensor and can rotate with high precision (Patent Document 1, FIG. 20 describes an embodiment applied to an image forming apparatus. ) By using such a motor, it is possible to reduce the size without a reduction gear.

  As a conventional example that achieves high-precision rotation and miniaturization, there is a planetary differential gear reducer. As a configuration that realizes downsizing of the driving device, there is one that uses a small speed reduction device. In the field of image forming apparatuses, as a mechanism for transmitting a rotational force from a driving source such as a motor through a speed reducing means, a mechanism using a toothed wheel train, a mechanism using a worm gear, a mechanism using a belt speed reducing mechanism, etc. are generally used. Is used. Examples of the rotating body in the image forming apparatus include an image bearing member such as a photosensitive member and an intermediate transfer member, a recording material conveying member that conveys a recording material, and a fixing roller. Rotate at rpm. On the other hand, the rotational speed of a motor used as a drive source for transmitting rotational force to a rotating body is generally several thousand rpm. In order to use a low-cost small-sized motor in a rotational speed range where energy conversion efficiency is high, a speed reduction means having a reduction ratio of about 1/10 to 1/30 is required to obtain the rotational speed required for the rotating body. Is required. As described above, the rotational accuracy of the rotating body in the image forming apparatus has a great influence on the image quality. However, in the conventional means using the tooth wheel train, the drive source is used for reasons such as part processing accuracy and assembly accuracy. It was difficult to transmit a highly accurate constant speed rotational force to the rotating body.

  In order to realize high-accuracy constant-speed rotational force transmission within a range where there is no practical problem in the image forming apparatus, for example, the transmission angular velocity fluctuation (hereinafter referred to as “angular velocity fluctuation” as appropriate) is reduced by reducing the number of deceleration stages. A method for reducing the number of occurrence points is mentioned. According to this method, effects such as cost reduction by reducing the number of parts, suppression of reduction in transmission efficiency, and noise reduction by meshing of gears can be expected as compared with multi-stage deceleration by a multi-tooth wheel train. As a reduction gear having a large reduction ratio and a small number of reduction stages, there is a planetary differential gear reduction device disclosed in Patent Document 2.

  Patent Document 2 proposes a planetary differential gear reduction device in which the number of teeth of the fixed gear and the output gear is small even when a large reduction ratio is obtained. This device has an output gear fixed to an output shaft connected to a drive target, and has a smaller number of teeth than the output gear, is arranged coaxially with the output gear, and is fixed so as not to rotate. And a fixed gear. Further, this device is a planetary gear that is supported by a planetary gear shaft that is driven to rotate around the outer periphery of an output gear and a fixed gear by a rotational force from a drive source, and rotates planetarily while meshing with both the output gear and the fixed gear. It has. In this planetary gear, the fixed gear meshing portion meshing with the fixed gear and the output gear meshing portion meshing with the output gear have the same number of teeth, the output gear, the fixed gear, the planetary gear meshing portion and the planetary gear output. At least one of the gear meshing portions is constituted by a shift gear.

  In this device, since the number of teeth of the fixed gear and the output gear are different from each other, smooth rotation drive cannot be realized just by meshing these gears with a single planetary gear as it is. Rotation drive is possible. And the reduction ratio obtained by this device is obtained based on the number of teeth of the fixed gear and the output gear regardless of the number of teeth of the planetary gear. The number of teeth of the fixed gear and the output gear can be small. Therefore, it is possible to reduce the size of the apparatus.

  In Patent Literature 3, in the planetary differential gear reduction device proposed in Patent Literature 1, a planetary differential gear reduction device capable of suppressing angular velocity fluctuations generated at a frequency according to the number of planetary gears and an image are disclosed. A forming apparatus has been proposed. The planetary image gear reduction device includes at least one tooth portion among an output gear, a fixed gear, a fixed gear meshing portion of the planetary gear, and an output gear meshing portion of the planetary gear constituting the planetary differential gear reduction device. Is formed of an elastic member that can be deformed by contact pressure generated by meshing while the drive target is rotationally driven.

By using such a planetary differential gear reduction device having a small reduction ratio and a high reduction ratio, the entire image forming apparatus can be reduced in size. Further, by having the configuration of Patent Document 3, high-precision component processing and assembly are possible. Without performing attachment or the like, the rotational accuracy of the driven object is increased, and high-precision image formation is possible. As an example of downsizing, if the planetary differential gear speed reduction device of Patent Document 3 is employed in a drum driving device of an image forming apparatus, particularly a driving device in a tandem type image forming apparatus, a driving source is provided on the extension of the photosensitive drum shaft. Compared to the case where a pair of toothed wheels having the same reduction ratio is used, the image forming portion (engine portion) is made smaller by comparing the motor and the speed reducer arranged in series. be able to.
JP 2004-282990 A JP 2003-42238 A Japanese Patent Laid-Open No. 2004-232834

  First, there is a reduction in the axial direction of the drive device. Many photoreceptor drums use organic materials and are treated as consumables due to wear deterioration over time. In the case of the photosensitive drum, since the replacement is performed several times during the product life of the image forming apparatus, a coupling portion (coupling) is provided between the photosensitive drum shaft and the output shaft of the speed reducer. A configuration in which the body drum is detachable from the image forming apparatus is employed. This coupling increases the axial space.

  There is also a drive transmission error due to coupling. If the coupling is installed between the output shaft of the speed reducer and the photosensitive drum shaft, a rotation transmission error (angular velocity fluctuation) newly occurs in the rotation of the photosensitive drum shaft. This occurs due to axial misalignment and declination between the photosensitive drum shaft and the speed reducer output shaft when the photosensitive drum is assembled to the image forming apparatus.

  Improving the rotation accuracy of the rotated body is also a problem. The rotational angular velocity fluctuations of the rotated body cannot be completely eliminated by suppressing it with parts processing and assembly accuracy. In actual use conditions, load fluctuations occur due to the cleaning member and the transfer member that are in contact with the photosensitive drum. For this reason, the torsion in the reduction gear, the coupling member, and the angular velocity fluctuation of the motor itself are generated and cannot be suppressed.

  That is, the problem to be solved by the present invention is to reduce the space occupied in the axial direction of the object to be driven (photosensitive drum, transfer belt driving roller, etc.).

  Another object of the present invention is that a driving object (photosensitive drum, transfer belt driving roller) can be attached to and detached from a speed reduction device or a motor fixed to the image forming apparatus main body without using a coupling member (coupling). It is to be.

  Yet another object of the present invention is to suppress fluctuations in the angular velocity of the driven object and to realize a stable rotational angular velocity with high accuracy.

  According to a first aspect of the present invention, there is provided a rotary body drive device including a drive source rotatably provided so that an axis of a hollow cylindrical member fixed to the device body is a rotation center in the rotary body drive device, and the drive source. A first gear provided on a cylindrical member or a disk member that rotates integrally with the rotating member, and a second gear fixed on the rotating shaft of the rotated body that receives rotational driving, and the rotating shaft of the rotated body Is inserted into the hollow cylindrical member so that the transmission force of the first gear is transmitted to the second gear directly or via another gear. The rotating shaft of the body and the second gear are detachable from the hollow cylindrical member including the drive source.

  That is, a rotating shaft (rotating cylindrical member or rotating disk) of a driving source such as a motor is configured with the hollow cylindrical member as a reference, and a driving target is inserted and supported inside the hollow cylindrical member. It becomes the structure which the to-be-driven body which is a drive object can be attached or detached. In addition, when the rotating body is mounted on the drive source side, the rotation axis of the driving source and the rotation axis of the rotating body, which cause a rotation transmission error to the rotating body side, are mounted with a slight misalignment and declination. And high-precision drive transmission.

  According to a second aspect of the present invention, there is provided a rotating body drive device according to the first aspect, further comprising a planetary differential gear reduction device for transmitting the rotational force of the drive source to the rotating shaft of the rotated body. The planetary differential gear reduction device has an output gear that is the second gear fixed to the rotating shaft of the rotating body, and has a smaller number of teeth than the output gear, and is coaxial with the output gear. And a fixed gear fixed in a non-rotatable manner and a planetary gear shaft that is driven to rotate around the output gear and the outer periphery of the fixed gear by the rotational force from the drive source, and the output gear and the A planetary gear that rotates in a planetary manner while meshing with both of the fixed gears, and a fixed gear meshing portion that meshes with the fixed gear in the planetary gear and an output gear meshing portion that meshes with the output gear have the same number of teeth, Output gear, Serial fixed wheel, at least one of the engagement portion of the output gear of the planetary gear of the fixing gear for meshing portions and the planetary gear, characterized by being constituted by a profile shifted gear.

  That is, even when the same reduction gear ratio is obtained as compared with the conventional tooth wheel train, the number of teeth of the fixed gear and the output gear can be reduced, and the number of teeth of the planetary gear can be arbitrarily set. Can be reduced. Further, by providing a plurality of planetary gears, in the transmission of rotational force, the load is distributed and the gears can be further reduced in size, and a highly accurate constant speed rotational force can be transmitted.

  The rotating body drive device according to claim 3 of the present invention is the rotating body drive device according to claim 2 or 3, wherein the planetary gear of the planetary differential gear reduction device is formed of a helical tooth, The helical teeth of the meshing portion and the meshing portion for the output gear are configured such that their twist directions are different from each other.

  Since the thrust force generated between the fixed gear and the output gear and the planetary gear can be canceled, the rotational force from the drive source can be stably transmitted to the drive target. Further, a force is always applied in the direction in which the output shaft inserted by utilizing this thrust force does not come out of the hollow cylindrical member.

  The rotating body drive device according to claim 4 of the present invention is the rotating body drive device according to any one of claims 2 to 4, wherein the planetary gear of the planetary differential gear speed reducer includes the fixed gear and the output gear. Three or more rotation shafts are arranged at equiangular intervals.

  Since the rotation balance when the planetary gear rotates on the planetary plane can be maintained and the gear load can be distributed, the vibration can be reduced. Further, since the output gear is supported by the three planetary gears, the output shaft inserted into the hollow cylindrical member and the shaft center of the output gear are supported in a direction that coincides with the shaft center of the fixed gear.

  The rotating body drive device according to claim 5 of the present invention is the rotating body drive device according to any one of claims 2 to 4, wherein the rotating body drive device includes the drive device with the speed reduction mechanism, the drive source is an outer rotor motor, The planetary gear is installed in the outer rotor portion of the outer rotor motor.

  A part of the outer rotor can be used as a rotating member. The outer rotor also serves as a case for protecting the inside of the motor. Therefore, the number of parts can be reduced, the structure can be simplified and the cost can be reduced, and the inertia is high, so the rotational stability is high. Assembly error factors can be reduced. Further, the apparatus can be thinned.

  According to a sixth aspect of the present invention, there is provided the rotary body drive device according to the first aspect, wherein the first gear is formed in a coupling shape, and the second gear is the first gear. It is formed in a coupling shape that can be fitted to the first gear, and is configured to rotate integrally with the first gear in the fitted state.

  By adopting a coupling using a fitting member, a state in which many teeth are engaged at the same time can be realized regardless of an axial mounting error, so that it is possible to transmit a rotational force resistant to load fluctuations.

  According to a seventh aspect of the present invention, in the rotary driving device according to the sixth aspect, involute teeth that mesh with each other are formed on the fitting surfaces of the first gear and the second gear, respectively. It is characterized by being.

  That is, since it is formed by a gear involute curve, a rotation transmission error due to an attachment error due to a shaft center deviation or the like is small.

  According to an eighth aspect of the present invention, in the rotary driving device according to the sixth aspect, trapezoidal teeth that mesh with each other are formed on the fitting surfaces of the first gear and the second gear, respectively. It is characterized by being.

  That is, the manufacturing cost and the inspection time of the product can be reduced due to the simple shape of the trapezoid.

  The rotating body drive device according to claim 9 of the present invention is the rotational drive device according to claims 6 to 8, wherein the second gear installed on the rotating shaft of the rotated body cannot move in the circumferential direction and Axial movement is supported, and an urging member is provided so as to be press-fitted to the first gear.

  Since the coupling member as the second gear escapes in the axial direction and is in pressure contact with the first gear, the tooth tip portion of the involute tooth repeatedly comes into contact with the tooth tip portion of the tooth. It is possible to prevent damage such as spillage and to realize a fitted state.

  The rotating body drive device according to a tenth aspect of the present invention is the rotary drive device according to any one of the first to ninth aspects, wherein a tip of the rotating shaft of the rotated body is formed in a tapered shape. .

  In other words, the tip of the rotating shaft inserted into the hollow cylindrical member is tapered so that the shaft can be easily mounted.

  According to an eleventh aspect of the present invention, in the rotary driving device according to any one of the first to tenth aspects, at least one of the second gear and the tooth tip portion of the second gear is tapered. It is formed.

  Even when the meshing of the two gears shifts in the circumferential direction and interferes with each other (collision) when the rotating shaft of the rotated body is mounted, one of them easily rotates and the mutual interference between them is eliminated. . Accordingly, quick mounting is possible, and the tooth tip portions are repeatedly brought into contact with each other, thereby preventing the tooth tip portions from being damaged such as tooth spills.

  According to a twelfth aspect of the present invention, in the rotary drive device according to any one of the first to eleventh aspects, the second gear is installed inside the cylindrical body to be rotated. Features.

  By installing the second gear inside the drum, the second gear can be protected by the drum in a state where the drum is extracted from the motor side. In addition, a part of the driving device at the time of mounting on the motor side is inserted into the drum, thereby realizing a reduction in the size of the rotation axis.

  According to a thirteenth aspect of the present invention, there is provided a rotary body drive device according to any one of the first to twelfth aspects of the present invention, comprising: a rotational speed detection means for detecting a rotational speed of the rotated body; and the rotational speed detection means. And a controller for controlling the rotation speed of the motor so that the rotation speed of the rotated body becomes a set speed based on a detection result.

  That is, by detecting the rotational angular velocity of the rotated body and adjusting the motor rotational speed, the rotation transmission error of the rotated body due to the machining accuracy of the parts is compensated, and stable driving at a desired rotational speed is realized.

  According to a fourteenth aspect of the present invention, in the rotary driving device according to the thirteenth aspect, the output rotational speed detecting means is arranged in a circumferential direction around the rotational axis of the rotated body N ( N is an integer greater than or equal to 2), and the controller detects the detected reduction gear output rotation speed based on the signals of the N sensors.

  By installing a plurality of rotation detection sensors (two in the embodiments described later), the mounting eccentricity of the magnetic ring is corrected to detect and control the rotational angular velocity of the rotating shaft of the rotated body.

  According to a fifteenth aspect of the present invention, there is provided the rotating body drive device according to the thirteenth or fourteenth aspect, wherein the detected board and the detection sensor constituting the rotational speed detecting means of the rotated body are respectively the rotated target device. It is installed in the case which protects a body and the said drive source.

  According to a sixteenth aspect of the present invention, in the rotary driving device according to the thirteenth or fourteenth aspect, the detected board and the detection sensor constituting the rotational speed detecting means of the rotated body are respectively the rotated body. And a housing that supports the drive source.

  A rotating body drive device according to a seventeenth aspect of the present invention is the rotary drive device according to any one of the thirteenth to sixteenth aspects, comprising the planetary differential gear reduction device, wherein the rotation detecting means outputs per one rotation. The number of signals is equal to or more than K × N × 4 from the reduction ratio K of the planetary differential gear reduction device and the planetary gear number N of the planetary differential gear reduction device.

  That is, it is possible to detect the rotational angular velocity fluctuation of the rotated body that occurs in the frequency cycle of the product of the motor rotational frequency and the number of planetary gears.

  The rotating body drive device according to claim 18 of the present invention is the rotational drive device according to claim 17, wherein the controller is a rotational angular velocity fluctuation of the rotated body that is generated at a frequency cycle of the product of the drive source rotational frequency and the number of planetary gears. The correction numerical value is calculated by detecting the amplitude and the phase.

  This makes it possible to correct and control rotational angular velocity fluctuations that are problematic when using the planetary differential gear reduction device described above.

  According to a nineteenth aspect of the present invention, there is provided a rotary drive device according to any one of the first to eighteenth aspects as a drive source.

  An image forming apparatus according to a twentieth aspect of the present invention includes the rotary drive device according to any one of the first to eighteenth aspects as a drive source for a cylindrical drum.

  An image forming apparatus according to a twenty-first aspect of the present invention is the image forming apparatus according to the twentieth aspect, wherein the cylindrical drum which is the rotated body is a photosensitive drum.

  That is, it is possible to obtain a high-quality image by driving the photosensitive drum with high accuracy.

  The present invention has a configuration in which a rotating body such as a drum to be driven can be attached to and detached from a driving source, and can be mounted in a state in which a rotation transmission error to the rotating body is very small. Drive transmission is possible.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  An electrophotographic color copier (hereinafter referred to as “copier”), which is an image forming apparatus that is an object of the present invention, will be described. The copying machine of this example is a so-called tandem image forming apparatus and employs a dry two-component developing system using a dry two-component developer, but the present invention is not limited to this.

  FIG. 1 is a schematic configuration diagram of the entire image forming unit in an example of a copying machine. This copying machine receives image data as image information from an image reading unit (not shown) and performs image forming processing. In this copying machine, as shown in the drawing, yellow (hereinafter abbreviated as “Y”), magenta (hereinafter abbreviated as “M”), cyan (hereinafter abbreviated as “C”). , Black (hereinafter abbreviated as “Bk”), photosensitive drums 1Y, 1M, 1C, and 1Bk, which are latent image carriers as four rotating bodies for each color, are arranged in parallel. These photosensitive drums 1Y, 1M, 1C, and 1Bk are arranged along the belt moving direction so as to contact the endless belt-shaped intermediate transfer belt 5 supported by a plurality of rotatable rollers including a driving roller. Has been placed. Around the photosensitive drums 1Y, 1M, 1C, and 1Bk, chargers 2Y, 2M, 2C, and 2Bk, developing devices 9Y, 9M, 9C, and 9Bk corresponding to the respective colors, cleaning devices 4Y, 4M, 4C, Electrophotographic process members such as 4Bk, static elimination lamps 3Y, 3M, 3C, and 3Bk are arranged in the order of processes.

  When a full-color image is formed by the copying machine of this example, first, as shown in FIG. 2, the photosensitive drum 1Y is rotated and driven in the direction of the arrow by a photosensitive member driving device to be described later with the charger 2Y. After being charged, a light beam LY from an optical writing device (not shown) is irradiated to form a Y electrostatic latent image on the photosensitive drum 1Y. This Y electrostatic latent image is developed with Y toner in the developer by the developing device 9Y. During development, a predetermined developing bias is applied between the developing roller and the photosensitive drum 1Y, and the Y toner on the developing roller is electrostatically attracted to the Y electrostatic latent image portion on the photosensitive drum 1Y.

  The Y toner image developed and formed in this way is conveyed to a primary transfer position where the photosensitive drum 1Y and the intermediate transfer belt 5 come into contact with the rotation of the photosensitive drum 1Y. At the primary transfer position, a predetermined bias voltage is applied to the back surface of the intermediate transfer belt 5 by the primary transfer roller 6Y. The Y toner image on the photosensitive drum 1Y is drawn toward the intermediate transfer belt 5 by the primary transfer electric field generated by this bias application, and is primarily transferred onto the intermediate transfer belt 5. Thereafter, similarly, the M toner image, the C toner image, and the Bk toner image are also primarily transferred so as to sequentially overlap the Y toner image on the intermediate transfer belt 5.

  Then, the toner images having the four colors superimposed on the intermediate transfer belt 5 are conveyed to a secondary transfer position facing the secondary transfer roller 7 as the intermediate transfer belt 5 rotates. Further, the transfer paper is conveyed to the secondary transfer position at a predetermined timing by a registration roller (not shown). At this secondary transfer position, a predetermined bias voltage is applied to the back surface of the transfer paper by the secondary transfer roller 7, and due to the secondary transfer electric field generated by the bias application and the contact pressure at the secondary transfer position, The toner image on the intermediate transfer belt 5 is secondarily transferred onto the transfer paper at once. Thereafter, the transfer paper on which the toner image is secondarily transferred is subjected to fixing processing by the fixing roller pair 8 and then discharged outside the apparatus.

  Next, a photosensitive member driving device which is a driving device with a speed reduction mechanism as a driving means including a planetary differential gear speed reduction device as a speed reduction means, which is a characteristic part of the present invention, will be described. Since each of the photosensitive drums 1Y, 1M, 1C, and 1Bk is driven to rotate by the photosensitive member driving device having the same configuration, the photosensitive member driving device for the photosensitive drum 1Y will be described below.

First, an overview of the rotating body driving device will be described.
FIG. 2 is a partial cross-sectional view of the photosensitive member driving device installed outside one end in the axial direction of the photosensitive drum 1 according to the first exemplary embodiment. Disk-shaped drum flanges 1 a are fixed to both ends of the photosensitive drum 1 in the axial direction so as to close the end surfaces of the photosensitive drum 1 in the axial direction. The center of the disk of the drum flange 1a is fixed to the end of the output shaft 11 of the photoconductor driving device 10, and is configured to transmit the rotational force from the output shaft 11. Further, the output shaft 11 is rotatably supported and supported by a bearing 100a of the side plate 100 constituting the internal casing of the copying machine according to the first embodiment so that smooth rotation is possible.

  The photoconductor driving device 10 is positioned on the photoconductor drum 1 side with respect to the side plate 100 and is fixed to the surface of the side plate 100. An output gear 16 to be described later is fixed to the output shaft 11, and the output shaft 11 is arranged in the photosensitive drum axis direction indicated by an arrow in the drawing, together with the fixed photosensitive drum 1 and the output gear 16, and the photosensitive member driving device 10. It is detachable from. Further, a magnetic ring 40 made by magnetizing NS poles fixed to the side surface of the photosensitive drum 1 and the photosensitive drum flange 1a at equal intervals and an MR sensor fixed to the side surface of the photosensitive member driving device 10 41, a speed detection mechanism is configured when the photosensitive drum is mounted on the photosensitive drum driving device 10, the rotational speed of the magnetic ring 40, that is, the photosensitive drum 1, is detected, and the detection result is driven by a motor. Sent to the controller.

  As a modification, FIG. 3 shows a partial cross-sectional view of a photosensitive drum driving device installed inside a cylindrical photosensitive drum 1. The drum flange 1a is fixed inside the photosensitive drum. An output gear 16 is fixed to the inside of the photosensitive drum on the output shaft 11 like the drum flange 1a. When the photoconductor drum is mounted on the photoconductor drive device 10, the photoconductor drive device is inserted into the photoconductor drum. In this case, there is a problem that heat generated when the motor rotates is trapped in the photosensitive drum. Therefore, a rotating fan (not shown) fixed to the output shaft 11 is attached in the vicinity of the drum flange 1a so that air is circulated from one end of the photosensitive drum to the other end, thereby causing a partial expansion of the drum due to heat generation. And other problems can be prevented.

  Next, the planetary differential gear reduction device will be described. FIG. 4 is a cross-sectional view showing the internal configuration of the photoreceptor driving device 10. FIG. 5 is a perspective view of the inside of the photoconductor driving device 10. The outer surface of the photosensitive member driving device 10 includes a cylindrical case 12 having openings at both ends and a disc-shaped lid member 13 that closes one opening of the case 12. The output shaft 11 is inserted through the center of the cylindrical member 13 a at the center of the disc of the lid member 13 and penetrates the photoconductor driving device 10. The tip of the output shaft 11 is processed into a taper so that it can be easily inserted. The lid member 13 and the cylindrical member 13 a are fixed with screws 24. Both members may be formed by a method such as integral molding or cylindrical caulking.

  Further, the lid member 13 may also serve as a side plate constituting the internal casing of the copying machine as shown in FIG. Here, considering the ease of assembly of the speed reducer, a method of fixing the end of the lid member 13 to the casing side plate was adopted. The other opening of the case 12 has a size that allows the output shaft 11 and the output gear 16 fixed to the output shaft 11 to pass therethrough. The cylindrical member 13a has a bearing 11b that rotatably supports the output shaft 11. In the vicinity of one of the bearings 11b of the cylindrical member 13a, there is a fixed gear 14 fixed to the cylindrical member 13a by press fitting. In this way, two places of the output shaft 11 penetrating the photoreceptor driving device 10 are rotatably supported. Here, in order to rotate the output shaft 11 smoothly, each of the bearings 11a and 11b needs to have a high degree of coaxiality. However, since the bearing 11a and 11b are fixed to the cylindrical member 13a, the assembly accuracy can be easily increased. .

  Further, inside the case 12 of the photosensitive member driving device 10, an output gear 16 that is firmly fixed to the output shaft 11 by a method such as press-fitting, and a disk member 17a are rotatable with respect to the cylindrical member 13a. A rotating disk 17 or the like as a power input member attached is provided. A cylindrical member 13a and an outer rotor 18 that rotates about the output shaft 11 are firmly fixed to the rotating disk 17 by caulking, press-fitting, an adhesive, or the like. Inside the outer rotor 18, a magnet 19 as a rotational force transmitting member is fixedly disposed on an inner peripheral surface parallel to the output shaft 11. Further, in the space between the inner peripheral surface and the output shaft 11, there are two stator cores 20 as drive sources in a flat stator holder 27 fixed to the lid member 13, and these stator cores 20 are magnets. 19 is arranged at a symmetrical position with respect to the output shaft 11 so as to have an optimal positional relationship with the output shaft 11.

  A planetary gear shaft 22 of a planetary gear 21 having a fixed gear 14 and an output gear 16 as sun gears is fixed to the rotating disk 17 by a method such as press fitting. A planetary gear 21 composed of a spur gear is rotatably attached to the planetary gear shaft 22. Three planetary gear shafts 22 are installed on the rotary disk 17 so as to be parallel to the output shaft 11 and to be equiangular about the output shaft 11. Further, the planetary gear shaft 22 is arranged such that the inter-axis distance with the output shaft 11 is an optimum distance for the planetary gear 21, the fixed gear 14, and the output gear 16 to mesh with each other. In order to maintain the positional relationship when the planetary gear 21 does not jump out of the planetary gear shaft 22 during rotation and the planetary gear 21, the fixed gear 14, and the output gear 16 mesh with each other, It is held on the planetary gear shaft 22 by a shaft retaining ring 23 or the like.

  When the outer rotor 18 rotates, the rotary disk 17 rotates about the output shaft 11. As a result, the planetary gear 21 rotates around the fixed gear 14 while rotating around the planet (revolution). Since the planetary gear 21 is also meshed with the output gear 16, the output gear 16 rotates by a difference in the number of teeth from the fixed gear 14. Here, at least one gear of the fixed gear 14 or the output gear 16 is set so that the actual meshing pitch circles of the gears 14 and 16 when the fixed gear 14 and the output gear 16 mesh with the planetary gear 21 are the same. It is configured as a shift gear. As a result, the planetary gear 21 can properly mesh with the fixed gear 14 and the output gear 16 having different numbers of teeth.

  FIG. 6 is a front view of the photoconductor driving device 10 as viewed from the axial direction of the output shaft 11. As illustrated, the fixed gear 14 and the output gear 16 are both arranged coaxially with the output shaft 11. The three planetary gears 21 rotate (revolve) in a planetary manner while maintaining an equal angle with respect to the central axis of the planetary rotation. Here, when the difference in the number of teeth between the fixed gear 14 and the output gear 16 is a multiple of 3, the planetary gear 21 is engaged with the fixed gear 14 and the output gear 16 as shown in FIG. The gear meshing portion has the same structure. On the other hand, when the difference in the number of teeth between the fixed gear 14 and the output gear 16 is other than a multiple of 3, the planetary gear 21 meshes with the fixed gear meshing portion 21a meshing with the fixed gear 14 and the output gear 16 as shown in FIG. One of the output gear engagement portions 21b has a structure that is shifted by 1/3 pitch with respect to the other. As a method of shifting the 1/3 pitch in this way, for example, when the planetary gear 21 is gear-cut with metal, it can be configured as an integral gear by press-fitting or caulking. Further, when the planetary gear 21 is a molded part, it can be easily manufactured by using a two-part mold. The phase difference between the fixed gear meshing portion 21a and the output gear meshing portion 21b can be corrected by shifting the pitch by 1/3.

  The reduction gear can be configured with one or more planetary gears. However, it is desirable to install three or more for the reasons described below. In the present embodiment, the output shaft 11 is configured to be inserted into the cylindrical member 13a, and the bearings 11a and 11b serving as the bearings of the output shaft 11 and the output shaft 11 are considered in consideration of the detachability of the output shaft. Some clearance is provided. This gap causes a rotational axis misalignment between the output gear 16 and the fixed gear 14. However, the planetary gear has the effect of aligning the axis of the output gear 16 and the fixed gear 14 simultaneously with the transmission of the driving force. This is because when there are three planetary gears, the position of the output gear 16 is shifted in the direction of aligning the axes to transmit the rotational force while supporting the output gear 16 at three points according to the position of the fixed gear 14. Work. For this reason, even if there is a slight gap as described above, it is possible to achieve high-accuracy rotation of the output shaft by aligning the shaft centers.

  The tooth tips of the output gear 16 and the three planetary gears 21 are formed into a taper shape or processed. When the photosensitive drum and the output gear 16 are mounted in the speed reducer, the tooth tip portion of the output gear 16 and the tooth tip portion of the planetary gear 21 are displaced in the circumferential direction from the original meshing position and collide with each other. There is. At this time, the photosensitive drum shaft 11 and the output gear 16 or the planetary gear 21 and the rotary disk 17 are easily rotated by the tapered surface of the tooth tip portion, and mutual interference between them is eliminated. Therefore, it becomes easy to mount the photosensitive drum, and it is possible to prevent the output gear 16 and the planetary gear 21 from being damaged such as tooth spillage.

  FIG. 9 is a partial cross-sectional view of the photoreceptor driving device 10 in which an inner rotor type DC motor is applied instead of the outer rotor motor as the second embodiment. Similar to the outer rotor type, on the output shaft 11, a rotating disk 17 serving as a motor rotating shaft of the inner rotor type DC motor is rotatably attached. An inner rotor 118 is fixed to the rotating disk 17. Has been. A magnet 119 is attached to the outer periphery of the inner rotor. A stator core 120 is fixed to the motor case 112 of the inner rotor 118. A planetary gear shaft 22 is fixed to the rotating disk 17 by press fitting or the like, and the planetary gear 21 is rotatably attached to the planetary gear shaft 22 in the same manner as described above. Although a DC motor is used here, a stepping motor, an AC motor, or the like can be similarly applied.

  FIG. 10 is a cross-sectional view of a direct drive system that directly transmits a motor driving force to the photosensitive drum 301 that is a rotation in Embodiment 3 of the present invention without using the reduction gear. An outer rotor type synchronous reactance motor as a drive motor is provided on one end side in the axial direction of the photosensitive drum 301. This motor includes a stator, and the stator core 320 has a shaft hole formed in the shaft center portion thereof, and a plurality of teeth projecting radially from the outer periphery of the stator core 320 about the shaft center of the shaft hole. Yes. A gap formed between the teeth around the axial center of the shaft hole becomes a slot, and the winding is wound around the two slots.

  In addition, a flat plate-shaped stator housing 313 serving as a base that extends in a direction orthogonal to the axial direction is integrally provided at one end of the stator in the axial direction so as to be separated from the end of the stator core 320. The stator housing 313 is fixed to a housing that supports a photosensitive drum and the like in the image forming apparatus, similarly to the lid member 13 of FIG. The stator housing may also serve as a part of the housing.

  On the other hand, a rotor 318 is provided outside the stator in the radial direction. The rotor 318 includes a rotor core 319. The rotor core 319 is formed in a substantially cylindrical shape as a whole by laminating, in the axial direction, an annular thin plate formed by punching a high magnetic permeability magnetic plate material such as a thin silicon steel plate. In the rotor core 319, a plurality of slit groups (not shown) penetrating in the axial direction are formed at equal intervals along the circumferential direction. This slit group forms a flux barrier in the rotor core 319. On the other hand, an arc-shaped portion made of a high permeability material left between the slits in the rotor core 319 forms a divided magnetic path.

  The rotor 318 is formed in a bottomed cylindrical shape (cup shape) with an axial hole, the inner diameter thereof corresponds to the outer diameter of the rotor core 319, and the depth (height inside the peripheral wall) is the axial dimension of the rotor core 319. It is considered to be slightly larger than. The rotor 318 has four screw holes provided at the bottom thereof corresponding to the mounting holes of the rotor core 319. The rotor 318 in which the rotor core 319 is accommodated is fixed in a state in which the end surface on one end side in the axial direction is in contact with the bottom of the rotor housing 317 serving as the output shaft of the motor.

  Further, a boss having an input side joint shaft hole is provided in the shaft center portion of the rotor housing 317, and the input side joint 330 can be integrally rotated by press-fitting or fitting into the input side joint shaft hole of the boss. It is connected. The input side joint 330 is rotatably supported by a bearing 317a as a bearing disposed in the vicinity of both ends of the hollow cylindrical member 313a in a state of rotating integrally with the rotor housing 317. The case 312 serves as a fixing member in the axial direction of the rotor housing 317 at the same time as a cover for holding the entire motor.

  On the other hand, an output side joint 331 is installed on the rotation shaft 311 of the photosensitive drum 301. The rotating shaft 311 of the photosensitive drum 301 is inserted so as to penetrate through the center of the hollow cylindrical member 313a, and is rotatably supported by a bearing 311a as a bearing provided in the hollow cylindrical member 313a. The input side joint 330 fixed to the motor side and the output side joint 331 fixed to the photosensitive drum shaft side are fitted together with the insertion of the rotating shaft 311. In this way, the motor rotation is transmitted to the photosensitive drum shaft.

  Here, as described above, the output side joint 331 as the first joint member is supported on the photosensitive drum shaft 311 so that the circumferential movement is impossible and the axial movement is possible. As an example, a groove is formed along the axial direction on the outer peripheral surface of the photosensitive drum shaft 311, and a pin (protrusion) to be inserted into the groove is formed in the shaft core portion of the output side joint 331. As a result, “the circumferential movement is impossible and the axial movement is supported”. On the other hand, an input side joint 330 as a second joint member is fixed to the motor side rotor housing 317.

  Both the output side joint 331 and the input side joint 330 are formed in a coupling shape, and the input side joint 330 is connected to the output side joint 331 by mounting the photosensitive drum to an image forming apparatus including a motor drive device. It is designed to be fitted. The fitting relationship is set so that the input side joint 330 is on the outside and the output side joint 331 is on the inside.

The output side joint 331 has a bottomed cylindrical shape and includes a bottom portion and a peripheral wall portion. As shown in FIG. 11 (A), involute teeth are formed on the outer peripheral surface of the peripheral wall portion, and the tip of the involute teeth is a tapered surface to ensure the ease of mounting the tray. A compression coil spring 332 is wound around the photosensitive drum shaft 311. One end of the compression coil spring 332 is abutted and locked to the casing 333, and the other end is abutted and locked to the bottom of the input side joint 330. Therefore, the compression coil spring 332 always presses and biases the output side joint 331 in a direction in which the output side joint 331 is separated from the casing 333.
The output side joint 331 is inserted and fitted into the input side joint 330 while absorbing the impact at the time of fitting the joint portion by the pressing bias consisting of the compression coil spring 332 and the casing 333. This makes it possible to prevent damage to the involute teeth of the joint portion. Here, the pressing force may be omitted depending on the number of times the photosensitive drum is attached and detached and the material of the joint portion. That is, the compression coil spring 332 may be removed, and the output side joint 331 may be fixed to the photosensitive drum shaft 311.

  On the other hand, the input side joint 330 has a bottomed cylindrical shape that is slightly larger than the output side joint 331, and includes a bottom portion and a peripheral wall portion. As shown in FIG. 11B, involute teeth that mesh with the involute teeth of the output side joint 331 are formed on the inner peripheral surface of the peripheral wall portion. Furthermore, the tip of the involute teeth is a tapered surface to ensure the ease of mounting the tray.

  Also in the direct drive system, as described with reference to FIGS. 2 and 3, it is possible to install a drive unit mainly composed of a motor outside the end of the photosensitive drum 1 or inside the photosensitive drum 1. is there. It is also possible to control the rotation speed of the photosensitive drum using a speed detection mechanism.

  Here, the speed detection mechanism will be described. Two MR sensors 41 fixed to the side surface of the lid member 13 of the photosensitive member driving device of FIG. 3 and a magnetic ring 40 having NS poles magnetized at equal intervals on the inner periphery of the side surface of the photosensitive drum 1. Have. The two MR sensors 41 are arranged at opposing positions. Each member constituting these speed detection mechanisms may be disposed on the inner surface of the drum 1. With this configuration, the rotational speed of the photosensitive drum 1 is detected, and the detection result is sent to the controller.

  As shown in FIG. 12, the controller 50 is a control circuit configured to output a motor drive signal composed of a CPU or the like, and based on the detection output from the MR sensor 41, the output rotation speed becomes a desired set value. Is a circuit for outputting a motor drive signal. The motor drive device 51 is a device for driving the motor 10 based on a motor drive signal from the controller 50.

  The controller 50 detects the rotational peripheral speed of the magnetic ring 40 that rotates integrally with the photosensitive drum by the two MR sensors 41, receives a signal (for example, a pulse train) from the MR sensor 41, and sets the target rotational speed. Is operated so as to reduce the phase difference between the signal (eg, a clock based on crystal oscillation) and the output signal of the MR sensor 41, and is configured by a general PLL circuit. Specifically, each detection pulse signal from the two MR sensors 41 and a pulse signal corresponding to the target set value are input to the controller 50, and the controller 50 detects the average position (average rising edge) of the phase of each detection pulse. Edge or average falling edge) and the phase of the pulse corresponding to the target set value are detected, and a signal is output so that these phase differences become zero.

  Here, the controller 50 can cancel the geometric detection error around the rotation axis of the magnetic ring 40 attached to the photosensitive drum portion by performing processing based on the pulse signals from the two MR sensors 41. .

  In this way, the rotational angular velocity of the photosensitive drum is detected as a pulse signal by the magnetic ring 40 and the MR sensor 41, and this pulse signal is input to the controller 50. In the controller 50, as described above, the phase difference between the rotational speed detection pulse obtained by the two MR sensors 41 and the reference pulse is detected, and a motor drive signal that eliminates this phase difference is input to the motor drive device 51. Is done. Then, the rotational speed of the motor is increased or decreased by a drive signal from the motor drive device 51.

When the planetary differential gear speed reducer as in the embodiment described above is used, it is desirable to set the number of NS poles magnetized on the magnetic ring 40 to be larger than a predetermined number. As described in Patent Document 3, even in the planetary differential gear speed reduction device according to the embodiment of the present invention, the rotational angular velocity of the output shaft at a frequency that is several times the number of planetary gears per motor rotation according to the number of planetary gears. Variations occur. For example, when the reduction ratio is 20, the number of planetary gears is 3, and the output shaft is rotated at 1 Hz, the rotational angular speed fluctuation of the output shaft occurs at a cycle of 20 × 3 = 60 Hz. Therefore, this rotational angular velocity fluctuation is detected, and the rotational speed of the motor is controlled so as to cancel the fluctuation. In this case, a detection signal that is at least four times the periodic variation is required. That is, 20 × 3 × 4 = 240 (number) NS poles, that is, a configuration in which a signal of 240 pulses per output shaft circumference is output from the MR sensor 41 is necessary. From such an output signal, the controller 50 recognizes the amplitude and phase of the rotational fluctuation component generated in three cycles per motor, and gives a command to cancel the motor driving device. As a result, the rotational angular velocity at the time of output becomes stable with high accuracy.

Schematic configuration diagram of the entire image forming unit in an example of a copying machine FIG. 2 is a partial cross-sectional view of a photosensitive member driving device installed outside one axial end portion of the photosensitive drum in Embodiment 1. Partial sectional view of a photosensitive drum driving device installed inside a cylindrical photosensitive drum Sectional drawing which shows the internal structure of a photoreceptor drive device using a planetary differential gear speed reducer Perspective view of the inside of the photosensitive member driving device Front view of the photoconductor drive device viewed from the axial direction of the output shaft Cross section of planetary gear Cross section of planetary gear Partial sectional view of Example 2 Sectional drawing of Example 3 of this invention Perspective view of output side joint and input side joint Block diagram showing control circuit configuration

Explanation of symbols

1Y, 1M, 1C, 1Bk Photosensitive drum 1a Drum flange 2Y, 2M, 2C, 2Bk Charger 3Y, 3M, 3C, 3Bk Static elimination lamp 4Y, 4M, 4C, 4Bk Cleaning device 5 Intermediate transfer belt 7 Secondary transfer roller 8 Fixing roller pair 9Y, 9M, 9C, 9Bk Developing device 10 Photoconductor driving device 11 Output shaft 11b Bearing 12 Case 13 Cover member 13a Cylindrical member 14 Fixed gear 16 Output gear 17 Rotating disk 17a Disk bearing 18 Outer rotor 19 Magnet 20 Stator core 21 planetary gear 21a meshing part for fixed gear 21b meshing part for output gear 22 planetary gear shaft 23 shaft retaining ring 24 screw 27 stator holder 40 magnetic ring 41 MR sensor 50 controller 51 motor drive device 100 side plate 100a bearing 112 motor Scan 118 the inner rotor 119 magnet 120 stator 301 photoreceptor drum 311 rotating shaft 313 a stator housing 313a hollow cylindrical member 317 rotor housing 317a bearing 318 rotor 319 rotor core 320 stator 330 input side joint 331 output side joint 311a bearing 332 compression coil spring 333 casing

Claims (21)

In the rotating body drive device,
A drive source that is rotatably provided so that the axis of the hollow cylindrical member fixed to the apparatus main body is the rotation center;
A first gear provided on a cylindrical member or a disk member that rotates integrally with the drive source;
A second gear fixed on the rotating shaft of the rotated body that receives rotational driving,
By inserting the rotating shaft of the rotated body into the hollow cylindrical member, the transmission force of the first gear is transmitted to the second gear directly or via another gear. And
The rotating body drive device characterized in that the rotating shaft of the rotated body and the second gear are detachable from the hollow cylindrical member including the drive source. The rotating body drive device according to claim 1, further comprising a planetary differential gear reduction device for transmitting the rotational force of the drive source to the rotation shaft of the rotated body,
The planetary differential gear speed reducer is
An output gear which is the second gear fixed to the rotating shaft of the rotated body;
A fixed gear having a smaller number of teeth than the output gear, arranged coaxially with the output gear, and fixed non-rotatably;
A planetary gear that is supported by a planetary gear shaft that is driven to rotate around the outer periphery of the output gear and the fixed gear by a rotational force from the drive source, and that rotates planetarily while meshing with both the output gear and the fixed gear. And
The fixed gear meshing portion that meshes with the fixed gear and the output gear meshing portion that meshes with the output gear in the planetary gear have the same number of teeth, and the output gear, the fixed gear, the fixed gear meshing portion of the planetary gear, and the A rotating body drive device characterized in that at least one of meshing portions for an output gear of a planetary gear is constituted by a shift gear. The rotary body drive device according to claim 2 or 3,
The planetary gear of the planetary differential gear reduction device is composed of helical teeth;
2. A rotating body drive device according to claim 1, wherein the helical gears of the fixed gear meshing portion and the output gear meshing portion are configured such that their twist directions are different from each other. In the rotary body drive device in any one of Claim 2 to 4,
3 or more of the planetary gears of the planetary differential gear speed reducer are arranged at equiangular intervals with respect to the rotation shafts of the fixed gear and the output gear. In the rotary body drive device in any one of Claim 2 to 4,
While including the drive unit with the speed reduction mechanism, the drive source is an outer rotor motor,
The planetary gear is installed in an outer rotor portion of the outer rotor motor, and is a rotation drive device. The rotary body drive device according to claim 1,
Forming the first gear into a coupling shape;
The second gear is formed in a coupling shape that can be fitted to the first gear, and is configured to rotate integrally with the first gear in the fitted state. Rotation drive device. In the rotation drive device of Claim 6,
An involute tooth that meshes with each other is formed on a fitting surface between the first gear and the second gear, respectively. In the rotation drive device of Claim 6,
The rotary drive device characterized in that trapezoidal teeth meshing with each other are formed on the fitting surfaces of the first gear and the second gear. In the rotation drive device of Claim 6 to 8,
The second gear installed on the rotating shaft of the rotated body is supported so that it cannot move in the circumferential direction but can move in the axial direction, and is urged so as to be press-fitted to the first gear. A rotary drive device comprising a member. The rotary drive device according to any one of claims 1 to 9,
The rotation drive device characterized in that the tip of the rotating shaft of the rotated body is tapered. In the rotation drive device in any one of Claim 1 to 10,
At least one of the second gear and the tooth tip portion of the second gear is formed in a taper shape. In the rotation drive device in any one of Claim 1 to 11,
The rotation drive device, wherein the second gear is installed inside the cylindrical body to be rotated. The rotary drive device according to any one of claims 1 to 12,
A rotational speed detecting means for detecting the rotational speed of the rotated body;
A controller for controlling the rotation speed of the motor so that the rotation speed of the rotated body becomes a set speed based on the detection result of the rotation speed detection means;
A rotary drive device comprising: The rotary drive device according to claim 13,
The output rotation speed detecting means has N (N is an integer of 2 or more) sensors arranged in a circumferential direction around the rotation axis of the rotated body,
The controller detects a reduction gear output rotation speed detected based on signals from the N sensors. The rotary drive device according to claim 13 or 14,
The rotation drive device according to claim 1, wherein the detection board and the detection sensor constituting the rotation speed detection means of the rotation object are installed in a case protecting the rotation object and the drive source, respectively. The rotary drive device according to claim 13 or 14,
The rotation drive device according to claim 1, wherein the detection board and the detection sensor constituting the rotation speed detection means of the rotation object are installed in a housing that supports the rotation object and the drive source, respectively. The rotary drive device according to any one of claims 13 to 16,
Having the planetary differential gear reducer,
The number of signals output per rotation by the rotation detecting means is not less than K × N × 4 from the reduction ratio K of the planetary differential gear reduction device and the planetary gear number N of the planetary differential gear reduction device. Rotational drive device characterized. The rotary drive device according to claim 17,
The controller detects an amplitude and a phase of a rotational angular velocity fluctuation of a rotating body generated at a frequency cycle of a product of a driving source rotational frequency and the number of planetary gears, and calculates a correction numerical value. An apparatus comprising the rotary drive device according to claim 1 as a drive source. An image forming apparatus comprising the rotary drive device according to claim 1 as a drive source of a cylindrical drum. The image forming apparatus according to claim 20, wherein
An image forming apparatus, wherein the cylindrical drum as the rotating body is a photosensitive drum.