JP2000088066A - Rotating device for rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotating device which rotates a rotor by transmitting thereto the driving force of a driving means using a gear transmission means and stops the rotor in the specified stop position, wherein stopping is generated accurately with dislocation prevented likely resulting from a backlash of the gears gear transmission means. SOLUTION: A rotating device includes a rotor 4a rotating round a rotary shaft, a driving means to rotate the rotor, and a gear transmission means to transmit the driving force of the driving means 60 to the rotor through a driving gear 62 and a follower gear 55, whereby the rotor is rotated and stopped in the specified position, and the arrangement further includes an aux. follower gear 56 supported by the rotary shaft rotatably and an energizing means 58 installed on the follower gear for energizing this aux. follower gear in the rotating direction of the follower gear, wherein the teeth of the driving gear are meshed upon pinching between the upstream flanks in rotating direction of the teeth of the follower gear and the downstream flanks in rotating direction of the teeth of the aux. follower gear energized in the rotating direction by the energizing means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating body rotating device having a stopping means for stopping a rotating body rotating about a rotating shaft at a predetermined stop position by driving means rotating by a gear transmission means.

[0002]

2. Description of the Related Art Conventionally, there is a rotating body rotating device that rotates a rotating body by a driving means and stops at a predetermined stop position, and uses a gear transmission means to transmit a driving force from the driving means to the rotating body. . However, when using the gear transmission means,
Due to the backlash of the gears, that is, the play between the tooth surfaces when the gears mesh with each other, even if the driving of the driving means is stopped, the rotating body may be displaced from a predetermined stop position and may not stop accurately at the stop position. In addition, there is a possibility that the stopped rotating body may deviate from the stop position and cause a position change. A rotary developing device of an image forming apparatus such as a copying machine, a facsimile, a printer, or the like is also known as the rotating body rotating device described above. In a revolver developing device as a rotary developing device, a driving unit rotates a developing unit having a plurality of developing units via a power transmission unit, stops the developing unit at a predetermined developing position, and performs development. I have. Generally, a stepping motor is used as the driving means because of its rotation angle controllability, and a gear connection as a gear transmission means is used as the power transmission means because of its high transmission force and high-precision rotation angle transmission. Have been. When the gear coupling is used, even if the stepping motor is stopped, the developing device of the developing device unit shifts from the developing position due to gear backlash, and does not stop accurately at the developing position, or the stopped developing device is moved to the developing position. , And may fluctuate from the developing position. As described above, when the developing device of the developing device unit does not stop accurately at the developing position or the developing device fluctuates from the developing position, the developing roller of the developing device shifts from a predetermined developing position facing the photoconductor. For example, the developing conditions such as the developing gap (distance between the photosensitive member and the developing roller) change due to the fluctuation or fluctuation. Therefore, an abnormal image such as uneven image density may occur. The gear backlash described above can be eliminated by making the distance between the gear and the connecting shaft according to the theoretical value, but it is impossible to eliminate the backlash for mass-produced gears in terms of cost.
Therefore, apart from the stepping motor, a stopper mechanism that operates in synchronization with the rotation of the developing unit is provided, assists in stopping the rotation of the developing unit at the developing position of the developing unit, and reduces the play of the drive system. I have.

[0003]

However, the vibration of the stopper mechanism engaging and disengaging the developing unit with the developing unit affects the machine, and causes the occurrence of abnormal images such as misalignment and banding. It has become. The present invention has been made in view of the above background, and the first object is to
A rotating body rotating device that transmits a driving force of a driving means to a rotating body by a gear transmission means to rotate the rotating body and stops the rotating body at a predetermined stop position. The rotating body stopping position due to backlash of a gear of the gear transmission means. It is an object of the present invention to provide a rotating body rotating device capable of preventing the rotating body from stopping at the stop position accurately. A second object of the present invention is to provide a rotating body rotating apparatus capable of holding a rotating body at a stop position by preventing a position change of the rotating body at a stop position due to a backlash of a gear of a gear transmission means in the above rotating body rotating device. It is to provide a device. Further, a third object is to provide a rotary developing device in which a driving force of a driving unit is transmitted to a supporting member that supports a plurality of developing units by a gear transmission unit to rotate, and an arbitrary developing unit is stopped at a developing position to perform development. In the device, without using a stopper mechanism to stop and hold the developing device at the developing position, it is possible to prevent the developing device from shifting to the developing position due to backlash of the gear of the gear transmission means, and to accurately develop the developing device. An object of the present invention is to provide a rotary developing device that can stop at a position and suppress occurrence of an abnormal image such as uneven image density and banding. A fourth object of the present invention is to prevent the fluctuation in the developing position of the developing device due to the backlash of the gear of the gear transmission means in the above-described rotary developing device, thereby preventing the occurrence of abnormal images such as uneven image density and banding. An object of the present invention is to provide a rotary developing device capable of suppressing the rotation.

[0004]

In order to achieve the first object, a first aspect of the present invention provides a rotating body which rotates about a rotating shaft, a driving means for rotating the rotating body, A gear transmitting means for transmitting a driving force from the driving means to the rotating body via a driving gear and a driven gear; and transmitting the driving force to the rotating body by the gear transmitting means to rotate. In a rotating body rotating device for stopping a rotating body at a predetermined stop position, a sub driven gear rotatably supported on a rotating shaft of the rotating body, and a biasing of the sub driven gear in a rotation direction of the driven gear. And a biasing means provided on the driven gear,
The teeth of the drive gear are sandwiched between the rotation-direction upstream tooth surfaces of the driven gear teeth and the rotation direction downstream tooth surfaces of the auxiliary driven gears that are urged in the rotation direction by the urging means. It is characterized by being engaged with.

In this rotating body rotating device, when the rotating body of the rotating body rotating device reaches a predetermined stop position and stops driving the driving means, the driven gear is driven downstream by the tooth surface of the driving gear in the rotation direction. The secondary driven gear is urged in the rotational direction by the urging means so that the upstream tooth flank in the rotational direction of the tooth contacts the rotating gear, and the downstream tooth flank in the rotational direction of the tooth of the secondary driven gear is rotated by the rotation of the tooth of the drive gear. In the direction upstream. Thereby, the teeth of the driving gear are sandwiched between the upstream tooth surface in the rotation direction of the teeth of the driven gear and the downstream tooth surface in the rotation direction of the teeth of the sub driven gear, and the rotation of the rotating body from the stop position due to the backlash of the gears. Displacement can be prevented.

According to a second aspect of the present invention, there is provided a rotating body rotating device according to the first aspect, wherein the driving means includes a rotating means for holding the rotating body at a predetermined stop position. It is characterized by using an electric device that generates a stopping force.

In this rotating body rotating device, even if the rotating body stopped at a predetermined stop position is displaced from the stop position, the displacement due to gear backlash is prevented, and the rotation stopping force of the driving means is reduced. Is transmitted to the rotating body via the drive gear, the driven gear, and the sub driven gear urged in the rotational direction by the urging means.

In order to achieve the third object, a third aspect of the present invention provides a plurality of developing devices for accommodating a developer, and the plurality of developing devices are integrally supported around a rotation shaft. A supporting member; a driving unit for rotating the supporting member about the rotation axis; and a gear transmission unit for transmitting a driving force of the driving unit to the supporting member via a driving gear and a driven gear. In the rotary developing device, the driving force is transmitted to the support member by the gear transmission means and rotated, and any of the plurality of developing devices is stopped at a developing position to perform development. An auxiliary driven gear rotatably supported,
Biasing means provided on the driven gear for biasing the sub driven gear in the rotation direction of the driven gear, wherein the teeth of the drive gear are provided on the upstream side in the rotational direction of the teeth of the driven gear; The auxiliary driven gear urged in the rotational direction by the urging means is interposed and meshed with the tooth surface on the downstream side in the rotational direction of the tooth of the sub driven gear.

In this rotary developing device, when the developing device of the rotary developing device reaches the developing position and stops the stepping motor, the rotation of the teeth of the driven gear in the direction of rotation of the teeth of the driving gear is performed. Driven auxiliary gear is urged in the rotational direction by urging means so that the upstream tooth surface of the drive gear contacts the downstream tooth surface of the drive gear tooth in the rotational direction of the tooth of the driven gear. Press on the surface. Thereby, the teeth of the driving gear are sandwiched between the upstream tooth surface in the rotation direction of the teeth of the driven gear and the downstream tooth surface in the rotation direction of the teeth of the sub driven gear, and the rotation of the rotating body from the stop position due to the backlash of the gears. Displacement can be prevented.

According to a fourth aspect of the present invention, there is provided a rotary developing device according to the third aspect, wherein the driving means comprises a rotation stopping force for holding the developing unit at a developing position. Characterized by using a stepping motor that generates

[0011] In this rotary developing device, even if the developing device stopped at the developing position is deviated from the developing position, the positional deviation due to gear backlash is prevented, and the rotation stopping force of the stepping motor is reduced. A drive gear,
The power is transmitted to the supporting member of the rotating body via the driven gear and the sub driven gear urged in the rotation direction by the urging means.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a color electrophotographic printer (hereinafter, referred to as a printer) as an image forming apparatus will be described below. First, the configuration and operation of the entire printer will be described. FIG. 1 is a schematic configuration diagram of a main part of the printer according to the present embodiment. A photosensitive drum 1 serving as a latent image carrier is driven to rotate in the direction of arrow A, and a charging charger 2 serving as a uniform charging means.
After being uniformly charged, the surface is scanned and exposed by the laser beam 3 from the laser optical device based on image information to form an electrostatic latent image on the surface. Here, the image information to be exposed is monochromatic image information obtained by decomposing a desired full-color image into yellow, magenta, cyan, and black color information. The electrostatic latent image formed on the photosensitive drum 1 is developed by a revolver developing device 4 as a rotary developing device with black toner, cyan toner, magenta toner, and yellow toner as predetermined developers, respectively. Thereby, each color image is formed on the photosensitive drum 1.

The toner images of respective colors formed on the photosensitive drum 1 are transferred to an intermediate transfer belt 5 rotating in the direction of arrow B in FIG. 1 in synchronization with the photosensitive drum 1 to form a black toner image, a cyan toner image, and a magenta toner image. , And the yellow toner image are superimposed and transferred by the primary transfer charger 6 to be synthesized into a full-color image as a synthesized image. On the other hand, the transfer sheet is conveyed from a sheet cassette (not shown) to a transfer section via a sheet roller (not shown) and a registration roller 9 while being synchronized with the rotation of the intermediate transfer belt 5. Then, the yellow, magenta, cyan, and black toner images superimposed on the intermediate transfer belt 5 are collectively transferred onto transfer paper by the secondary transfer charger 11 of the transfer section. After the transfer is completed, the toner image is fixed on the transfer paper by a fixing device (not shown), and the transfer paper is discharged outside the apparatus as a full-color print.

The toner on the photosensitive drum 1 that has not been transferred onto the intermediate transfer belt 5 is removed by the photosensitive cleaner 13.
As a result, the toner on the intermediate transfer belt 5 that has been removed from the photosensitive drum 1 and has not been transferred onto the transfer paper is removed from the intermediate transfer belt 5 by the intermediate transfer belt cleaner 14.

Next, a revolver developing device 4 as a rotary developing device according to the present embodiment will be described. FIG.
2A is a cross-sectional view illustrating the internal structure of a developing unit of the revolver developing device, and FIG. 2B is a cross-sectional view illustrating the internal structure of the toner container unit 4b of the revolver developing device. The developing device unit 4a as a rotating body of the revolver developing device 4 has an outer housing 4d as a substantially cylindrical support member which is rotatably mounted around a central axis in the printer main body. In the outer housing 4d, developing devices 41Bk, 41Y, and 4Y each using toner of each color of black, yellow, magenta, and cyan, respectively, are provided.
1M and 41C are formed. Further, the toner container unit 4b of the revolver developing device 4 is attached so as to be substantially coaxial with the developing unit 4a in front of the developing unit 4a in the rotation axis direction. It is designed to rotate integrally with the camera.

The above-mentioned developing units 41Bk, 41Y, 41
Since M and 41C have the same internal structure, the black developing device 41Bk at the developing position will be described. A developing roller 42Bk as a developer carrier and first and second stirring screws 43Bk and 44Bk substantially parallel to the developing roller 42Bk are provided in the black developing device 41Bk. Second stirring screw 43Bk, 44
Bk transports the developer in the developing device 41Bk in the axial direction opposite to each other while stirring the developer. The toner container unit 4b includes four toner hoppers 45Bk and 45Bk.
Y, 45M, 45C, and corresponding toner cartridges 48Bk, 48Y, 48M, 48C, and the like. The above toner hoppers 45Bk, 45Y, 45M,
45C has the same internal structure, so the toner hopper 45Bk for black toner will be described. The toner hopper 45Bk corresponds to the developing device 41Bk, and supplies toner to the developing device 41Bk. The toner hopper 45Bk is provided with a toner supply pipe 46Bk toward the developing device 41Bk, and a toner conveying screw 47Bk is provided in the toner supply pipe 46Bk. The toner transport screw 47Bk transports the toner in the toner hopper 45Bk to the developing device 41Bk.

A toner cartridge 48Bk is attached to the toner receiving port of the toner hopper 45Bk so as to be connected to the toner discharge port, and the toner is supplied from the toner cartridge 48Bk to the toner hopper 45Bk. .

FIG. 3 is a schematic sectional view showing a developing unit, a stepping motor, a connecting gear for connecting the stepping motor and the developing unit according to the present embodiment, and the like. FIG. 4A is a rear view of the sub revolver gear connected to the revolver gear by a spring and the drive gear as viewed from the stepping motor side. Note that the right side in FIG. 3 shows the back side of the apparatus, and the left side in FIG. 3 shows the front side of the apparatus. The developing unit 4a is held between the front side plate 50 of the revolver and the rear side plate 51 of the revolver.
And a revolver gear 55 as a driven gear are fixed coaxially with the developing unit 4a. The revolver gear 55 includes a gear portion 55a and a boss portion 55b.
Stats 55c, 55c, 55c
Is protruding. The developing device unit 4a has a center shaft 52 on the front plate 54 of the main body and a bearing 53, and a boss 55b of the revolver gear 55 has a bearing 54 on the rear plate 57 of the main body.
And are rotatable.

A sub revolver gear gear 56 as a sub driven gear is fitted in the boss 55b of the revolver gear 55. The sub revolver gear 56 has the same tooth profile dimensions as the revolver gear 55, such as a module and the number of teeth. The sub revolver gear 56 has an oval hole 56.
a, 56a, 56a are provided, and these holes 56
a, 56a, a stat 56 on the upstream side in the rotational direction of 56a.
b, 56b, 56b are protruded. The sub-revolver gear 56 has oval holes 56a, 56a, 56a
Stats 55c and 5 of the gear portion 55a of the revolver gear 55
The free ends of 5c and 55c protrude and are inserted, and the sub revolver gear 56 is rotatable within a predetermined range with respect to the revolver gear 55. The above stats 55c, 55
c, 55c and the stats 56b, 56b, 56b are connected by a tension spring 58, and the sub revolver gear 56
Is pulled in the rotation direction of the revolver gear 55 by a tension spring 58. On the other hand, a stepping motor 60 as a driving means is provided behind the rear plate 57 of the main body, and a driving gear 62 is fixed to a driving shaft 61 of the stepping motor 60. The drive gear 62 is meshed with a gear portion 55a of the revolver gear 55 with a predetermined backlash. Note that the revolver developing device 4 includes:
Developing unit 4a, revolver gear 55, sub revolver gear 56, stepping motor 60, and drive gear 62
And so on.

Next, the meshing of the drive gear according to this embodiment with the revolver gear and the sub-revolver gear based on the above configuration will be described. FIG. 4B shows a driving gear,
It is the enlarged view which expanded the engagement part with a revolver gear and a sub revolver gear. When the developing unit of the developing unit 4a is in the developing position and the rotation of the stepping motor 60 is stopped, a smaller current is supplied to the stepping motor 60 to excite a predetermined phase to rotate the stepping motor 60. Generates static torque as a stopping force. The static torque is transmitted from the drive shaft 61 to the developing unit 4a via the drive gear 62, the revolver gear 55, and the sub-revolver gear 56. At this time, the teeth of the driving gear 62 are sandwiched between the teeth of the revolver gear 55 and the teeth of the sub-revolver gear 56, and the tooth surface of the driving gear 62 on the downstream side in the rotation direction is the revolver gear 5.
5 is in contact with the upstream tooth surface in the rotation direction of the tooth 5, and the upstream tooth surface in the rotation direction of the teeth of the sub-revolver gear 56 is brought into contact with the upstream tooth surface in the rotation direction of the teeth of the drive gear 62 by the spring force of the spring 58. It is pressed and in contact. As a result, even if the developing device of the developing device unit 4a attempts to change from the developing position, the change is prevented.

When the stepping motor 60 is rotating to move the developing unit of the developing unit 4a to the developing position, a larger current is supplied to the stepping motor 60 while the stepping motor 60 is stopped, and the switched phase is changed. It is sequentially excited to generate a rotational torque as a driving force. The rotation torque of the stepping motor 60 is transmitted from the drive shaft 61 to the developing unit 4a via the drive gear 62, the revolver gear 55, and the sub revolver gear 56. With the rotation of the drive shaft 61 of the stepping motor 60, the drive gear 62 rotates in the direction of the arrow in the figure, and the tooth surface of the drive gear 62 on the downstream side in the rotational direction presses the tooth surface on the upstream side in the rotational direction of the revolver gear 55. Then, the revolver gear 55 is rotated in the rotation direction.
At this time, the tooth surface of the sub revolver gear 56 on the downstream side in the rotational direction presses the tooth surface of the drive gear 62 on the upstream side in the rotational direction with the spring force of the spring 58. Thereby, the driving gear 6
2 rotates the revolver gear 55 and the sub revolver gear 56 in the rotation direction, and the rotation of the revolver gear 55 causes the developing unit 4a to rotate. And the developing unit 4
When the developing device of FIG. 4A is close to the developing position and the stepping motor 60 is decelerated, the rotation of the drive gear 62 is reduced, but the developing device unit 4a tries to continue rotating in the rotational direction due to its inertia. The rotation-direction upstream tooth surfaces of the 56 teeth abut against and press the rotation-direction upstream tooth surfaces of the drive gear 62 teeth. However, the upstream tooth surface in the rotation direction of the teeth of the drive gear 62 presses the upstream tooth surface in the rotation direction of the teeth of the sub-revolver gear 56, and the rotation of the developing unit 4a in the rotation direction is suppressed.

Next, when the developing unit of the developing unit 4a reaches the developing position, a smaller current is supplied to the stepping motor 60 during rotation, and a predetermined phase is excited to generate a static torque. The static torque of the stepping motor 60 is transmitted from the drive shaft 61 to the drive gear 62, the revolver gear 5
5 and to the developing unit 4a via the sub-revolver gear 56. At this time, the stepping motor 60
When the rotation of the drive gear 62 is stopped along with the rotation stop of the drive shaft 61, the upstream tooth surface in the rotation direction of the teeth of the drive gear 62 stops pressing the upstream tooth surface in the rotation direction of the teeth of the sub-revolver gear 56, and the developing device The rotation of the unit 4a in the rotation direction is stopped, and the rotation-side upstream tooth surface of the revolver gear 55 is brought into contact with the rotation-side downstream tooth surface of the drive gear 62 in the rotation direction. Thus, in a state where the developing unit of the developing unit 4a is stopped at the developing position, the developing unit develops the electrostatic latent image on the photosensitive drum 1 with the toner. According to the above-described embodiment, when the rotation of the stepping motor 60 is stopped and the developing device of the developing device unit 4a is stopped at the developing position, the tooth surface of the sub revolver gear 56 on the downstream side in the rotation direction is caused by the spring force. The drive gear 62 presses the upstream tooth surface of the revolver gear 55 in the rotational direction, and stops with the downstream tooth surface of the drive gear 62 in the rotational direction abutting on the upstream tooth surface in the rotational direction of the tooth of the revolver gear 55. . As a result, the shift of the gear to the stop position due to gear backlash is prevented, the developing device of the developing device unit 4a can be stopped accurately at the developing position, and occurrence of abnormal images such as uneven density can be suppressed. Further, in the above-described embodiment, the case of the revolver developing device of the printer as the rotary developing device of the image forming apparatus has been described, but the present invention is not limited to this, and the rotating body that rotates about the rotating shaft is driven. Any means may be used as long as the rotating means rotates through the gear of the gear transmission means and stops at a predetermined stop position.

[0023]

According to the first aspect of the present invention, when the rotating body of the rotating body rotating device reaches a predetermined stop position and stops driving the driving means, the tooth surface of the driving gear tooth in the rotational direction downstream side. So that the tooth surface on the upstream side in the rotational direction of the tooth of the driven gear abuts,
The auxiliary driven gear is urged in the rotational direction by the urging means, and the downstream tooth surface in the rotation direction of the teeth of the auxiliary driven gear is pressed against the upstream tooth surface in the rotation direction of the teeth of the drive gear. Thereby, the teeth of the driving gear are sandwiched between the upstream tooth surface in the rotation direction of the teeth of the driven gear and the downstream tooth surface in the rotation direction of the teeth of the sub driven gear, and the rotation of the rotating body from the stop position due to the backlash of the gears. Since the displacement can be prevented, there is an effect that the rotating body can be accurately stopped at a predetermined stop position. Further, since the effect of stopping the rotating body at the predetermined stop position can be expected without being influenced by the finished dimensions of the individual gears, there is also an effect that the cost for increasing the precision of parts does not increase.

According to the second aspect of the present invention, even if the rotating body stopped at the predetermined stop position shifts from the stop position, the position shift due to the backlash of the gear is prevented, and the rotation of the driving means is stopped. Since the force is transmitted to the rotating body via the driving gear, the driven gear and the sub driven gear urged in the rotating direction by the urging means, there is an effect that the rotating body is held at the stop position.

According to the third aspect of the present invention, when the developing device of the rotary developing device reaches the developing position and stops the stepping motor, the tooth of the driven gear is driven downstream of the tooth of the driving gear in the rotation direction. The auxiliary driven gear is urged in the rotational direction by the urging means such that the upstream tooth surface in the rotational direction abuts, and the downstream tooth surface in the rotational direction of the teeth of the auxiliary driven gear is located upstream in the rotational direction of the teeth of the drive gear. Press on the tooth surface. Thereby, the teeth of the driving gear are sandwiched between the upstream tooth surface in the rotation direction of the teeth of the driven gear and the downstream tooth surface in the rotation direction of the teeth of the sub driven gear, and the rotation of the rotating body from the stop position due to the backlash of the gears. Because it can prevent displacement,
The developing device of the rotary developing device can be accurately stopped at the developing position without using a stopper mechanism for stopping and holding the developing device at the developing position. Therefore, there is an effect that occurrence of an abnormal image such as banding and density unevenness is suppressed.

According to the fourth aspect of the present invention, even if the developing device stopped at the developing position attempts to deviate from the developing position, the positional shift due to gear backlash is prevented, and the rotation stopping force of the stepping motor is reduced. Is transmitted to the support member of the rotating body via the driving gear, the driven gear, and the sub driven gear urged in the rotational direction by the urging means. Thereby, the developing device is held at the developing position, and the developing conditions such as the distance between the developer carrier and the latent image carrier are not changed, so that the occurrence of abnormal images such as uneven image density is suppressed. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of an electrophotographic printer according to an embodiment.

FIG. 2A is a cross-sectional view showing an internal structure of a developing unit of the revolver developing device of the printer. (B) Sectional drawing which shows the internal structure of the toner container unit of the revolver developing device.

FIG. 3 is a schematic cross-sectional view showing the developing unit, a stepping motor, and a connection gear for connecting the stepping motor to the developing unit.

FIG. 4A is a rear view of a gear connected to the revolver gear by a tension spring and a drive gear as viewed from a stepping motor side. (B) An enlarged view in which the driving gear and a meshing portion with the gear are enlarged.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2 Charger 3 Laser beam 4 Revolver developing device 4a Developing unit 4b Toner container unit 4d Outer case 5 Intermediate transfer belt 6 Primary transfer charger 9 Registration roller 11 Secondary transfer charger 13 Photoconductor cleaner 14 Intermediate transfer Belt cleaner 55 Revolver gear 55a Gear part 55b Boss part 56 Gear 58 Tension spring 60 Stepping motor 62 Drive gear

Claims (4)

[Claims] A rotating body that rotates about a rotating shaft; a driving unit for rotating the rotating body; and a driving force transmitted from the driving unit to the rotating body via a driving gear and a driven gear. A rotating body rotating device having a gear transmitting means, wherein the driving force is transmitted to the rotating body by the gear transmitting means, the rotating body is rotated, and the rotating body is stopped at a predetermined stop position. A secondary driven gear rotatably supported on the driven gear; and biasing means provided on the driven gear to bias the secondary driven gear in the rotation direction of the driven gear. The toothed surface of the driven gear is sandwiched and meshed between the tooth surface of the driven gear on the upstream side in the rotational direction and the tooth surface of the auxiliary driven gear on the downstream side in the rotational direction urged in the rotational direction by the urging means. Rotating body rotating device. 2. The rotating body rotating device according to claim 1, wherein an electric device for generating a rotation stopping force for holding said rotating body at a predetermined stop position is used as said driving means. Body rotation device. A plurality of developing devices for accommodating a developer; a support member for integrally supporting the plurality of developing devices around a rotation axis; and rotating the support member about the rotation shaft. And a gear transmitting means for transmitting the driving force of the driving means to the supporting member via a driving gear and a driven gear, and transmitting the driving force to the supporting member by the gear transmitting means. In the rotary developing device that rotates and stops an arbitrary developing device of the plurality of developing devices at a developing position and performs development, a sub driven gear rotatably supported on the rotating shaft; and the sub driven gear. An urging means provided on the driven gear to urge the driven gear in the rotation direction, wherein the teeth of the drive gear are formed by the tooth surface of the driven gear in the rotational direction upstream tooth surface and the urging means. The rotation direction downstream of the teeth of the sub driven gear urged in the rotation direction A rotating body rotating device characterized by being sandwiched between and meshed with a side tooth surface. 4. The rotary developing device according to claim 3, wherein a stepping motor for generating a rotation stopping force for holding said developing unit at a developing position is used as said driving means. apparatus.