JP4410340B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly to an image forming apparatus having a multi-color developing unit positioning mechanism that rotates to develop a predetermined color.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an image forming apparatus capable of color copying includes an intermediate transfer member to which toner images of a plurality of colors are sequentially transferred from a photosensitive member (image carrier). In such an image forming apparatus, the toner images of a plurality of colors are sequentially transferred from the photosensitive member to the intermediate transfer member and superimposed, and then the overlapping toner image of the intermediate transfer member is transferred to the transfer unit by the rotation of the intermediate transfer member. And transferred to the transfer material conveyed to the transfer portion.
[0003]
In order to form a toner image of a plurality of colors on a photoconductor, a rotary developing unit (hereinafter sometimes referred to as a “multicolor developing unit”) having developing devices for each color such as cyan, magenta, and yellow. The developer is rotated and a predetermined color developer is set at the development position. For example, before the leading end of the cyan latent image formed on the photosensitive member reaches the developing position, the cyan developing device is opposed to the photosensitive member by the rotation of the rotary developing unit, and the leading end of the cyan latent image is also detected. When the portion reaches the developing position, rotation of the developing sleeve of the cyan developing unit is started, and the cyan latent image on the photosensitive member is developed with cyan toner.
[0004]
In such an image forming process, it is necessary to accurately position the developing device of a predetermined color at a developing position facing the photoreceptor. Conventionally, for such positioning, for example, a stepping motor is used as the rotational power of the multicolor developing unit, and the rotational power is turned off by a predetermined number of steps, and the detent claw is placed on a predetermined portion of the multicolor developing unit. Is done by setting.
[0005]
[Problems to be solved by the invention]
However, when the multi-color developing unit is rotated by the stepping motor and the developing device is positioned at the developing position, there is a problem that a slight deviation may occur and accurate positioning cannot be performed. In addition, when a stepping motor is used, a dedicated driver, a pulse generator (pulse generator), and the like are required, and there is a problem that the configuration becomes complicated.
[0006]
SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of accurately positioning a developing device of a multicolor developing unit with respect to a developing position with a simple configuration.
[0007]
[Means for Solving the Problems]
  According to the first aspect of the present invention, one of a plurality of different developers for each color is moved to a predetermined development position by a DC brushless motor, whereby a predetermined color is formed on the image carrier carrying the electrostatic latent image. An image forming apparatus including a multi-color developing unit that visualizes the electrostatic latent image by supplying the toner, and input means provided in each of the developing devices, and is connectable to the input means and Output means positioned corresponding to the developing position; position correcting means provided at a connecting portion between the output means and the input means; control means for controlling driving of the DC brushless motor; and the DC brushless A load torque generating means for applying a load to drive the motor; and a load detecting means for detecting a load on the DC brushless motor, wherein the output means includes an output shaft and an output member fixed around the output shaft. The input means includes an input shaft coupled to the output shaft and an input member fixed around the input shaft, and the position correcting means is formed at an input side end of the output shaft. A convex or concave spherical shape, and a concave or convex spherical shape that is formed at an output side end portion of the input shaft and fits with an end portion of the output shaft, and the control means includes:When one of the developing devices is stopped at the predetermined developing position, a load is generated by the load torque generating means, and a load generated by the load torque generating means is detected by the load detecting means,The supply of power to the DC brushless motor is stopped by the detection signal from the load detection means, and the positioning of each developing device at the development position is determined by the spherical shape of the output shaft and the spherical shape of the input shaft. And the transmission of the driving force to each developing device is a member / part different from the positioning, and a recess or a claw part formed in the output member, and the input member It is formed by fitting with the claw part or the recessed part which fits the recessed part or the claw part of the output member.
[0008]
  In the first aspect of the invention, the multicolor developing unit is rotated by the DC brushless motor so that one of the developing devices is positioned at the developing position, and the input means provided in the developing device is By connecting the output means positioned at the development position, it is not necessary to separately provide a dedicated driver, a pulse generator or the like as in the case of using a stepping motor, so that the configuration is simple. At this time, the positioning of each developing device to the developing position is performed by fitting and connecting the spherical shapes of the end portions of the output shaft and the input shaft, which are position correction means, so that the positioning configuration is simple, Absorption of corners is possible, accurate positioning can be performed, and displacement of transferred images can be prevented..
  MaWhen stopping the rotational movement of the multi-color development unit,By control by control meansThe load torque generating means applies a load to the DC brushless motor, and the control means stops driving the DC brushless motor by stopping power supply to the DC brushless motor by a detection signal from the load detecting means that detects the load. Therefore, the rotational movement of the multicolor developing unit can be stopped reliably.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 and 2 are configuration diagrams schematically showing an image forming apparatus to which the present invention is applied.
[0019]
The image forming apparatus 40 is a color electrostatic image forming apparatus provided with an intermediate transfer belt 10 as an intermediate transfer body, and is a color that reads and separates an original image into color image data that is an electrical signal. It has a scanner and a laser writing unit 5 as exposure means.
[0020]
The writing unit 5 includes a laser light emitting means (laser diode) (not shown), a light emission control drive unit (not shown) for controlling light emission (laser light 5D) of the laser light emitting means, a polygon mirror 5B, and a rotation of the polygon mirror 5B. Motor 5A, f / θ lens 5C, and reflecting mirror 5F. With this configuration, the writing unit 5 converts the color image data from the color scanner into an optical signal, performs optical writing with the laser beam 5D corresponding to the document image, and forms a belt-like photoconductor as an image carrier. An electrostatic latent image is formed on the surface of 1. That is, the light from the laser emitting means is scanned by the polygon mirror 5B that is rotationally driven by the motor 5A, passes through the f / θ lens 5C, the reflection mirror 5F, and the like, reaches the photosensitive member 1, and on the charged photosensitive member 1. To form a latent image corresponding to the written information.
[0021]
The photosensitive member 1 is rotatably supported by rotating rollers 2 and 3 and rotates clockwise as indicated by an arrow A in the drawing, for example. Around the photoconductor 1, a photoconductor cleaning device 15 having a cleaning blade 15A and a waste toner collecting container 15B, a static elimination lamp L, and a charging device 4 are arranged.
[0022]
A writing unit 5 that irradiates a laser beam 5D is provided at a position downstream of the charging device 4. At a position downstream of the optical writing unit, a selected developing device (cyan developing device C in the figure) of a rotary developing unit 6 (hereinafter also referred to as a multicolor developing unit) as developing means. A black developing unit 7 containing black toner and an intermediate transfer belt 10 are disposed.
[0023]
The rotary developing unit 6 includes a cyan developing device C, a magenta developing device M, and a yellow developing device Y. The rotary developing unit 6 is rotated (moved) by 120 degrees by driving a DC brushless motor 90 described later, and one of the developing devices C, M, and Y is moved to the developing position. Each of the developing units C, M, and Y draws up the developing sleeve and the developing sleeve that rotate by bringing the ears of the developer into contact with the surface of the photosensitive member 1 in order to visualize the electrostatic latent image on the photosensitive member 1. And a developing paddle that rotates for stirring.
[0024]
In the present embodiment, any one of the developing device and the developing units 7, C, M, and Y moves to a developable position in synchronization with the development timing of the corresponding color. In this case, when the developing devices C, M, and Y are operated, the black developing unit 7 is moved to a position separated from the photoreceptor 1. This movement is controlled by the rotation of the cam 45.
[0025]
The intermediate transfer belt 10 is rotatably supported by rotating rollers 11 and 12. A bias unit 13 is provided on the back surface of the intermediate transfer belt 10, and the toner image on the photoreceptor 1 is transferred to the surface of the intermediate transfer belt 10 by the bias unit 13. A cleaning device 16 for cleaning the surface of the intermediate transfer belt 10 is provided in the vicinity of the rotary roller 11 that supports the intermediate transfer belt 10. The cleaning blade 16 </ b> A of the cleaning device 16 can be brought into and out of contact with the intermediate transfer belt 10 via a contact / separation arm (not shown).
[0026]
The cleaning blade 16A is separated from the intermediate transfer belt 10 when a toner image is transferred from the photoreceptor 1 to the intermediate transfer belt 10, and the transfer material (recording medium such as paper or plastic) 17A is separated from the intermediate transfer belt 10. After the toner image is transferred, the toner contacts with the intermediate transfer belt 10 and scrapes the residual toner on the intermediate transfer belt 10.
[0027]
The transfer material 17A onto which the toner image is transferred is fed from a paper feeding device (paper feeding cassette) 17 via a paper feeding roller 18 and a conveying roller pair 19, and is transferred at a predetermined timing by the registration roller pair 20 to the intermediate transfer belt 10. And the transfer roller 14. On the other hand, in the stage before the transfer material 17A is conveyed, toner images of predetermined colors are sequentially formed on the photosensitive member 1, and the toner images of the respective colors are sequentially transferred to the same position on the intermediate transfer belt 10 each time. (Every time the intermediate transfer belt 10 rotates, one color is transferred).
[0028]
In this case, the photoreceptor 1 is cleaned for each color to prepare for the formation of the next color. The toner images of a plurality of colors that are sequentially transferred and superimposed on the intermediate transfer belt 10 are collectively applied to the transfer agent 17 </ b> A sent to the nip portion between the intermediate transfer belt 10 and the transfer roller 14 by the action of the transfer roller 14. Transcribed. The transfer material 17A on which the toner images of a plurality of colors are collectively transferred is then sent to the fixing device 50 where the toner image is fixed, and a discharge roller 51 is provided on the upper portion of the frame 9 of the apparatus main body. The paper is discharged to the paper stack unit 52.
[0029]
The waste toner scraped off from the photoreceptor 1 and the intermediate transfer belt 10 by the cleaning blades 15A and 16A is stored in a waste toner collection container 15B. In this case, an auger and conveying means (not shown) provided inside the cleaning devices 15 and 16 convey waste toner scraped off by the cleaning blades 15A and 16A and send it to the collection container 15B. The collection container 15 is appropriately replaced according to the amount of waste toner stored.
[0030]
As shown in FIG. 2, the unitized process cartridge 31 integrally incorporates the photosensitive member 1, the charging device 4, the intermediate transfer belt 10, the cleaning devices 15 and 16, a conveyance guide that forms a transfer material conveyance path, and the like. It has a configuration that can be exchanged for the lifetime. Further, in order to facilitate the replacement of the process cartridge 31, the multi-color developing device 6, the black developing device 7 and the like and the jam processing, a part of the front frame 8 of the apparatus main body is rotated about the support shaft 9A to be the apparatus. It is designed to release the body.
[0031]
  In the main body of the device,SystemThe control device E is stored. Above the electric transmission / control device E, a fan F is provided for releasing heat to the outside in order to prevent an overtemperature in the machine. Further, another relatively small paper feeding device MF is provided in the apparatus main body on the right side in the drawing. In the figure, OP is an operation panel.
[0032]
FIG. 3 shows the multicolor developing unit 6. As shown in the figure, the multi-color developing unit 6 has cyan, magenta, and yellow developing devices C, M, and Y, and a gear 61 provided on the outer periphery of the end thereof is supplied from the DC brushless motor 90. By engaging with a driving gear 63 that rotates by obtaining a driving force, it rotates (moves) about the rotating shaft 62. Further, the multi-color developing unit 6 has a powder brake 95 that is a load torque generating means, and a power source 96 that supplies electric power to the powder brake 95. The multicolor developing unit 6 has a toner hopper 60 for each color.
[0033]
A clock (pulse generation source) 91 is built in the DC brushless motor 90, and the clock 91 generates a pulse corresponding to the rotational speed of the DC brushless motor 90. The DC brushless motor 90 is rotationally controlled by a control unit 92 described later, and rotationally drives the multicolor developing unit 6 to a predetermined position before creating a latent image on the photoreceptor 1.
[0034]
By using the DC brushless motor 90, it is not necessary to separately provide a dedicated driver, a pulse generator, or the like as in the case of using a stepping motor, for example, so that the configuration is simple.
[0035]
When the power is supplied from the power source 96, the powder brake 95 fixes the gear portion 95a and the rotating shaft 95b with powder, and applies a load to the rotation of the gear 61 (the brake is applied). ing). The operation of the powder brake 95 is also controlled by the control means 92.
[0036]
The control unit 92 controls the DC brushless motor 90 by so-called PLL control (phase synchronization control), and sends a motor start signal to the DC brushless motor 90 to supply power 93 before the latent image of the photoreceptor 1 is created. The DC brushless motor 90 is rotationally driven by supplying electric power from.
[0037]
A pulse corresponding to the rotational speed of the DC brushless motor 90 is input to the control unit 92 in advance, and when this pulse and the pulse of the DC brushless motor 90 coincide (when in a locked state), DC When the power is supplied to the brushless motor 90 and they do not match (when in a lock error state), the power supply to the DC brushless motor 90 is stopped (cut).
[0038]
The control unit 92 includes a load detection unit 94, and stops power supply to the DC brushless motor 90 in response to a signal from the load detection unit 94. The load detection means 94 compares the pulse from the clock 91 built in the DC brushless motor 90 with the pulse input in advance to the control means 92, and when these pulses do not match, the control means A signal to that effect is sent to 92.
[0039]
Specifically, when the multicolor developing unit 6 is rotated 120 degrees (when one of the developing devices C, M, and Y is located at the developing position), the control unit 92 supplies power from the power source 96 to the powder brake 95. Thus, a load torque is applied from the powder brake 95 to the gear 61 (the brake is applied). When a load torque is applied to the gear 61 (a load is applied to the driving of the DC brushless motor 90), the pulse from the clock 91 of the DC brushless motor 90 and the pulse previously input to the control means 92 do not match ( The load detection means 94 that has detected this sends a detection signal to this effect to the control means 92. Upon receiving a signal from the load detection means 94, the control means 92 stops the power supply to the DC brushless motor 90, and thereby the rotational drive of the DC brushless motor 90 is stopped.
[0040]
Since the control unit 92 stops the power supply to the DC brushless motor 90 and thereby stops the driving of the DC brushless motor 90, the multicolor developing unit 6 can be stopped reliably.
[0041]
FIG. 4 shows a driving unit 64 that drives the developing devices C, M, and Y of the multicolor developing unit 6. The driving unit 64 includes an input unit 65 provided in the developing device C and an output unit 66 that can be connected to the input unit 65. Although the developing devices M and Y are also provided with input means, the configuration thereof is the same as the input means 65 of the developing device C. Therefore, only the input means 65 of the developing device C will be described, and the developing devices M and Y will be described. Description of the input means is omitted.
[0042]
The input means 65 has an input shaft 70 connected to the developing device C, and the rotational force from the output means 66 is transmitted to the input shaft 70 so that the developing device C is rotationally driven. It has become. The end portion 70a of the input shaft 70 has a convex spherical shape that is a position correcting means that protrudes toward the output shaft 73 side.
[0043]
An input member 71 is fixed around the input shaft 70. On the end surface of the input member 71 on the output means 66 side, a claw 71a that fits into a concave portion 72a of the output member described later protrudes. In addition, in this Embodiment, although the nail | claw 71a has comprised the column shape, it is not limited to this, For example, a triangular pyramid shape and a square pillar shape may be sufficient.
[0044]
The output means 66 is positioned corresponding to the developing position, and has an output shaft 73 connected to the input shaft 70 and an output member 72 connected to the input member 71. The output shaft 73 extends so as to penetrate the frame 9 of the apparatus main body. An end 73a on the input shaft 70 side of the output shaft 73 has a concave spherical shape that is a position correcting means for fitting with the convex spherical surface of the end of the input shaft 70. The output shaft 73 and the input shaft 70 are These spherical surfaces are connected by fitting.
[0045]
The output member 72 is fixed around the output shaft 73 so as to face the input member 71. The end surface of the output member 72 on the input member 71 side is formed with a recess 72a at a position facing the claw 71a of the input member 71, and the claw 71a of the input member 71 is fitted into the recess 72a. . The output shaft 73 is rotatably supported by the frame 9 via a bearing 98.
[0046]
A gear portion 72 b is formed on the outer peripheral surface of the base end portion of the output member 72. The gear portion 72b meshes with a driving gear (not shown) that rotates by obtaining a driving force from a motor (not shown) of the apparatus main body. Therefore, when the output member 72 rotates by driving the motor of the apparatus main body, the output shaft 73 rotates accordingly.
[0047]
The transmission of the driving force from the output shaft 73 to the input shaft 70 is performed by the contact / separation mechanism 67 that detachably engages the output member 72 with the input member 71. The contact / separation mechanism 67 is disposed between the cam 75 fixed to the end of the output shaft 73 that protrudes outward through the frame 9, and the output member 72 is connected to the input member 71. A spring 74 that is always urged in a direction away from the lever, a lever 77 that is rotatably attached to a support shaft 78 supported on the apparatus body side, and that can come into contact with the cam 75; and an end of the lever 77; In addition, a plunger 84 that rotates the lever 77 about the support shaft 78 and a solenoid 80 that pushes and pulls the plunger 84 are configured.
[0048]
  In the contact / separation mechanism 67 having such a configuration, when the plunger 84 is moved in the direction C in the drawing by the suction action of the solenoid 80, the lever 77 rotates around the support shaft 78 in the direction D in the drawing and the cam 75 Is moved in the direction opposite to the C direction against the biasing force of the spring 74. Thereby, the output member 72 together with the output shaft 73 is connected to the cam 75.sameThe recess 72a of the output member 72 is engaged with the claw 71a of the input member 71 (the output member 72 and the input member 71 are surface-engaged). Accordingly, the rotational drive of the output shaft 73 is input (transmitted) to the input shaft 70.
[0049]
By providing the output member 72 and the input member 71 that are in surface engagement with each other, for example, between the output shaft 73 and the input shaft 70, a transmission member (for example, a shaft) that transmits the drive of the output shaft 73 to the input shaft 70 is provided. And the like, and the like.
[0050]
Moreover, what is necessary is just to turn OFF the solenoid 80, when canceling | transmitting transmission of rotational force. Thereby, the output shaft 73 (cam 75) is pushed back by the restoring force of the spring 74, and the surface engagement between the output member 72 and the input member 71 is released. In this configuration, the lever 77 is in contact with the small diameter portion of the cam 75 in the non-transmitting state shown in FIG. 4, but when the lever 77 is rotated by the plunger 84 (when the rotational force is transmitted), The cam 75 is pressed in contact with the large diameter portion.
[0051]
Next, the operation of the present embodiment will be described based on the configuration described above. The DC brushless motor 90 is driven by the motor start signal from the control means 92, and the multicolor developing unit 6 is rotated. When the cyan developing device C reaches the developing position, the powder brake 95 applies a load to the drive of the DC brushless motor 90, resulting in a lock error (when the control unit 92 receives a signal from the load detection unit 94), the DC The power supply to the brushless motor 90 is stopped, and the rotation of the multicolor developing unit 6 is stopped.
[0052]
  When the rotation of the multicolor developing unit 6 is stopped, the developing device C is positioned at the developing position as shown in FIG. An input shaft 70 provided in the developing device CInOn the other hand, the output shaft 73 positioned at the developing position by the contact / separation mechanism 67 is connected. At this time, even if the developing device C is displaced from the developing position, the concave spherical surface of the output shaft 73 is fitted along the inclined surface of the convex spherical surface of the input shaft 70, so that the developing device C is accurately positioned at the developing position. Is done. Then, the developing device C is driven by the input shaft 70 to which the drive of the output shaft 73 is transmitted, and a cyan toner image is formed on the photoreceptor 1.
[0053]
In this way, the output shaft in which the input shaft 70 of the developing device C is positioned corresponding to the development position via the concave and convex spherical shapes of the input and output shaft ends 70a and 73a, which are position correction means. By connecting to 73, the developing device C can be accurately positioned. Further, since the connecting portion of the output shaft 73 and the input shaft 70 is connected by fitting the concave and convex spherical surfaces, it is possible to absorb the declination.
[0054]
  On the other hand, when the developing unit C is positioned at the developing position only by the DC brushless motor 90, when the multi-color developing unit 6 is rotated and the developing unit C is stopped at the developing position, a slight deviation occurs. However, in this embodiment, the output shaft 73 positioned at the developing position is connected to the developing device C.ofSince it is connected to the input shaft 70, accurate positioning can be performed and displacement of the transferred image can be prevented.
[0055]
After the cyan toner image is formed on the photosensitive member 1, the magenta developing device M and the yellow developing device Y are sequentially positioned at the developing position in the same process as described above, and the respective color toner images are formed on the photosensitive member 1. A plurality of color toner images are formed on the photoconductor 1 by sequentially superposing them. The multiple color toner images are transferred to the intermediate transfer belt 10, and the multiple color toner images on the intermediate transfer belt 10 are transferred to the transfer material 17 </ b> A from the paper feeding device 17. Thereafter, the toner images of a plurality of colors transferred to the transfer material 17 </ b> A are fixed by the fixing device 50 and discharged to the discharge stack unit 52.
[0056]
  The present inventionA reference example will be described.For example, in the present embodiment, spherical end portions 70a and 73a of the input and output shafts are used as the position correcting means.As an example, inputas well asoutputPosition correction means may be provided at the connecting portion of the members 71 and 72. That is, as shown in FIG. 5, an inclined surface (position correcting means) 72c is provided in the recess 72a of the output member 72 so that the claw portion 71a of the input member 71 fits into the recess 72a along the inclined surface 72c. In this case, even if the position of the developing device C is shifted, the claw portion 71a of the input member 71 is fitted into the recess 72a, so that the developing device C can be accurately positioned.
[0057]
In this embodiment, the output member 72 is provided with a recess 72a and the input member 71 is provided with a claw 71a. However, the output member 72 is provided with a claw, and a recess that can be fitted to the claw is formed in the input member. You may do it.
[0058]
Furthermore, in the present embodiment, the end portion 70a of the input shaft 70 has a convex spherical shape and the end portion 73a of the output shaft 73 has a concave spherical shape. However, the end portion 70a of the input shaft 70 has a concave spherical shape and is output. The end 73a of the shaft 73 may have a convex spherical shape.
[0059]
In the present embodiment, the powder brake 95 is provided on the gear 61, but may be provided on the drive gear 93, for example. Although the powder brake 95 is used as the load torque generating means, the present invention is not limited to this. For example, a load is applied by providing a contact / separation member that can contact / separate the gear 61 and bringing the contact / separation member into contact with the gear 61. It suffices that the DC brushless motor 90 is driven.
[0060]
【The invention's effect】
  According to the first aspect of the present invention, a dedicated driver, a pulse generator, and the like are separately provided as in the case of using a stepping motor by positioning one of the developing devices at the developing position using a DC brushless motor. Since there is no need to provide it, the configuration is simple and the positioning of each developer unit to the development position is performed by fitting and connecting the spherical shapes of the output and input shaft ends, so the positioning configuration is simple. Yes, this makes it possible to absorb declination, perform accurate positioning, and prevent transfer image displacement..
  MaWhen stopping the rotational movement of the multi-color development unit,The load torque generating means applies a load to the DC brushless motor by the control by the control means,Based on the detection signal from the load detection means, the control means stops the power supply to the DC brushless motor, thereby stopping the drive of the DC brushless motor, so that the rotational movement of the multicolor developing unit is reliably stopped. Can be made.
[Brief description of the drawings]
FIG. 1 is a configuration diagram schematically showing an image forming apparatus to which the present invention is applied.
FIG. 2 is a diagram illustrating a state in which a unitized process cartridge is removed from the image forming apparatus of FIG. 1;
FIG. 3 is a perspective view of a multicolor developing unit.
FIG. 4 is a cross-sectional view schematically showing a driving unit that drives each developing device of the multicolor developing unit.
[Figure 5]Reference exampleIt is sectional drawing which expands and shows the connection part vicinity of the input and output member concerning.
[Explanation of symbols]
1 Photoconductor (image carrier)
6 Multicolor development unit
40 Image forming apparatus
65 Input means
66 Output means
70 input shaft
70a Convex spherical end of input shaft (position correcting means)
71 Input member
72 Output member
73 Output shaft
73a Concave spherical end of output shaft (position correcting means)
90 DC brushless motor
92 Control means
94 Load detection means
95 Powder brake (load torque generating means)

Claims (1)

By moving one of a plurality of different developing devices for each color to a predetermined development position by a DC brushless motor, toner of a predetermined color is supplied onto the image carrier carrying the electrostatic latent image, and electrostatic latent An image forming apparatus including a multicolor developing unit for visualizing an image,
Provided in an input means provided in each of the developing devices, an output means that can be connected to the input means and positioned corresponding to the development position, and a connecting portion between the output means and the input means Position correcting means, control means for controlling the driving of the DC brushless motor, load torque generating means for applying a load to the driving of the DC brushless motor, and load detecting means for detecting the load on the DC brushless motor. Have
The output means includes an output shaft and an output member fixed around the output shaft, and the input means includes an input shaft coupled to the output shaft, and an input member fixed around the input shaft. With
The position correcting means is formed at a convex or concave spherical shape formed at an input side end portion of the output shaft, and is formed at an output side end portion of the input shaft and fits with an end portion of the output shaft. With a concave or convex spherical shape,
The control means generates a load by the load torque generating means when stopping one of the developing devices at the predetermined developing position, and the load generated by the load torque generating means is applied to the load detecting means. Detection, and stop the power supply to the DC brushless motor by the detection signal from the load detection means,
Each developing device is positioned at the developing position by fitting and connecting the spherical shape of the output shaft and the spherical shape of the input shaft, and driving force is transmitted to each developing device. , A member / part that is different from the positioning, and a recess or a claw formed in the output member, and a claw or a claw formed in the input member that fits into the recess or the claw of the output member An image forming apparatus, which is performed by fitting with a recess.

Images