JPH0411030B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention can be suitably used generally in color recording devices constituting the output section of color electrophotographic copying machines and computers and facsimile machines, and in particular, The present invention relates to a color image forming apparatus in which a plurality of developing units are mounted on a movable support, and a desired developing unit is moved to a position facing a developing object, which is a latent image carrier, to perform development.

A developing device suitable for the present invention may be a rotary developing device in which the movable support is a rotating body and each developing unit is given a rotational motion, or the movable support can be moved, for example, in an elliptical motion or in a parallel vertical motion. It is also possible to use a type of developing device that performs non-rotational movement. Furthermore, both a dry type and a wet type developing device can be used.

Furthermore, the color image forming apparatus according to the present invention includes:
The above-mentioned color electrophotographic copying machine, color recording apparatus, etc. are not limited to full-color machines, but may be monochrome machines with two or three or more colors, so-called multi-color machines.

BACKGROUND OF THE INVENTION Recently, the demand for color copying has increased rapidly not only in specialized fields but also in general office work, and there is a desire for a color copying machine that can be used not only by professionals but by anyone. Currently, full-color electrophotographic copying machines that utilize electrophotographic technology are generally widely used as color copying machines.

Full-color electronic copying machines still have various problems that need to be solved or improved, but one of them is how to visualize the electrostatic latent images of each color formed on the object to be developed, that is, the photoreceptor. The problem lies in how the developing device is configured.

Conventionally, various means have been proposed as developing devices for color electrophotographic copying machines, but they can be broadly classified into two types. One of them is a side-by-side developing device, in which a plurality of developing units each having a developer of each color are arranged in parallel along the surface of a photoreceptor, and is currently most commonly used. In a commercially available electrophotographic copying machine, the photoreceptor is usually a cylindrical drum, so the developing units of the developing device are arranged close to the surface of the photoreceptor drum and arranged in parallel along the circumferential direction of the photoreceptor drum. Placed.

The second developing device is a so-called rotary developing device in which a rotating wheel is provided adjacent to the photoreceptor and a plurality of developing units are arranged around the wheel, as disclosed in, for example, Japanese Patent Application Laid-Open No. 47-131. It is a device.

Problems to be Solved by the Invention As mentioned above, side-by-side developing devices are currently widely used, and according to these developing devices, developing units having a plurality of different color developers are simply placed around the photosensitive drum one after another. It seems that the structure is simple because all you have to do is to line up the developing units, but in reality, while one developing unit is operating, the remaining developing units need to be inactive. Therefore, it is necessary to control the rotation of the magnetic brush roller in the developing unit or to move the developing unit itself away from the surface of the photosensitive drum, and in the end, the side-by-side developing device also requires a complicated structure and complicated operation control. Forced.

Furthermore, according to this type of developing device, since a plurality of developing units are sequentially arranged around the photosensitive drum, the diameter of the photosensitive drum inevitably becomes large, which makes it difficult to downsize the electrophotographic copying machine. It is extremely difficult. Furthermore, although the position where the latent image of each color is formed on the photosensitive drum is constant, the developing position of each color by the developing unit is different, and therefore the time required for the latent image of each color to be developed is different. Correction of the time decay of the latent image is required. Such correction work is not technically simple and complicates the control of the developing device and the copying machine as a whole.

On the other hand, rotary developing devices carry out development by placing only the developing unit of the desired color in opposition to the latent image on the photosensitive drum. It has the advantage that it can be made smaller and does not require correction of the time decay of latent images of each color. However, a concrete and practical structure for how to efficiently drive each rotatably moving developing unit to perform a developing operation has not yet been proposed.

The developing device described in Japanese Patent Application Laid-Open No. 47-131 has four developing units installed between two rotatably mounted wheels on the machine base, and each developing unit is moved horizontally by a planetary gear system. Although the developing device is configured to rotate, the developing roller of the developing device only contacts the object to be developed and is rotated by the movement of the object to be developed. In other words, the developing device is not provided with a driving device. Although such a system can be applied to a wet type developing device, it does not disclose or suggest any means for solving the technical problems of a dry type developing device using a magnetic brush roller or the like.

OBJECTS OF THE INVENTION Accordingly, the main object of the present invention is to provide a color image forming apparatus which has a plurality of developing units and which moves the required developing units to one common developing position for each color. It is an object of the present invention to provide a color image forming apparatus equipped with a driving means that is connected extremely smoothly and does not damage a developing unit driving section.

Another object of the present invention is to provide a driving means that can suitably mesh with the input gear portions of any developing unit and transmit driving force even if the input gear portions of each developing unit are slightly shifted in position. An object of the present invention is to provide a color image forming apparatus with the following features.

Still another object of the present invention is to provide a color image forming apparatus equipped with a drive means that can be suitably applied even when the developing device performs not only rotational movement but also other elliptical movement or parallel vertical movement. It is to provide.

Still another object of the present invention is to provide a color image forming apparatus equipped with a driving means that does not require a driving device for each developing unit, thereby simplifying the structure of the developing unit and developing device and facilitating maintenance management. It is to provide.

Means for Solving the Problems The above objects are achieved by a color image forming apparatus according to the present invention.

The color image forming apparatus of the present invention includes an image carrier;
A latent image forming means for forming an electrostatic latent image corresponding to each color image on the image carrier; a developer carrying member for carrying and conveying developer and applying it to the image carrier; and a drive for driving this developer carrying member. a plurality of developing units each having a drive input gear that receives a force, each of which applies a developer of a different color to the image carrier; a movable support movable along a predetermined path so as to move the developing unit to one developing position common to each color; a movable support that engages with and drives a drive input gear of the developing unit that has been moved to the developing position; A drive means having a drive gear for transmitting force, the drive means being swingably provided on a pivot fixed at a predetermined position along the movement path of the movable support, and a swinging member supporting the drive gear; , an elastic member that biases the swinging member so that the drive gear enters the movement locus of the drive input gear of the developing unit as the movable support moves; a first regulating member that locks the swinging member when not engaged with the drive input gear to regulate the amount of entry of the drive gear into the drive input gear movement locus; Each of the developing units has a second regulating member that locks the swinging member when the drive input gear and the drive gear are engaged to regulate the distance between the centers of the two gears. It is an image forming apparatus. According to a preferred embodiment, the drive means includes an electric motor, and a clutch rotatable in only one direction is provided in the drive transmission path from the electric motor to the drive gear, or a clutch for connecting and disconnecting the drive force is provided. A clutch is provided.

Embodiment Next, a color image forming apparatus according to the present invention will be described in detail with reference to drawings illustrating one embodiment thereof.

The color image forming apparatus according to the present invention can use various developing devices, but in this embodiment, a dry rotary developing device is used in a full color electrophotographic copying machine.

Further, full-color electrophotographic copying machines perform various electrostatic latent image forming processes, such as primary charging-secondary charging/
Color separation exposure - so-called NP, including various processes of full-surface exposure
Although other methods may be used, this embodiment describes an electrophotographic copying machine to which the Carlson process is applied.

FIG. 2 shows a full-color electrophotographic copying machine in a schematic cross-sectional view.

First, to explain the overall structure of a full-color electrophotographic copying machine, approximately in the center of the copying machine is a photosensitive drum 1 having an electrophotographic photosensitive layer formed on its surface.
is placed. The photosensitive drum 1 is rotatably and removably attached to a rotary support shaft 2 in a well-known manner. In this embodiment, it is assumed that the photosensitive drum 1 rotates in the direction of arrow 3, that is, counterclockwise in FIG.

A primary charger 4 is located approximately directly above the photosensitive drum 1.
A rotary developing device 100 is arranged on the left side of the photosensitive drum 1 in FIG. 2, a transfer drum 5 is arranged approximately directly below the photosensitive drum 1, and a cleaning device 6 is arranged on the right side of the photosensitive drum 1 in FIG. .

Further, an optical system 10 is disposed in the upper part of the electrophotographic copying machine, and the image of the original O on the platen 7 is transferred to the exposure section 8 located between the primary charger 4 and the rotary developing device 100. It is configured to project onto the photosensitive drum 1. Although any optical system can be used as the optical system 10, in this embodiment, the first scanning mirror 1
1. It is composed of second and third scanning mirrors 12 and 13 that move in the same direction at half the speed of the first scanning mirror 11, an imaging lens 14, and a fourth fixed mirror 15. The optical system 10 is a slit exposure type optical system well known to those skilled in the art, and further explanation of its operating principle is unnecessary. Further, the document irradiation light source 16 is configured to move together with the first scanning mirror 11, and the color separation filter 17 is arranged between the fourth fixed mirror 15 and the exposure section 8.

Therefore, the first, second and third scanning mirrors 11,
The reflected light image of the original O scanned by 12 and 13 passes through the lens 14, passes through the fourth fixed mirror 15, is color separated by the color separation filter 17, passes through the dustproof glass 18, and is exposed to light at the exposure section 8. An image is formed on the drum 1.

A fixing device 20 and a paper feed device 30 are arranged on the right side of the full-color electrophotographic copying machine in FIG. Further, the transfer drum 5 and the fixing device 20
Transfer material conveying systems 25 and 35 are disposed between the recording medium and the paper feeding device 30, respectively.

The operation of the full-color electrophotographic copying machine configured as described above will be briefly explained.

The photosensitive drum 1 begins to rotate in the direction of the arrow 3 at the start of operation, and is charged by the primary charger 4 .
The charged photosensitive drum 1 further rotates, and an optical image is slit-exposed in the exposure section 8 by the action of the optical system 10 described above, and electrostatic latent images of each color are formed on the photosensitive drum 1. The latent image on the photosensitive drum 1 is then brought by rotation of the photosensitive drum 1 to a developing area 40 in which a rotary developing device 100 is arranged. In the developing area 50, the electrostatic latent image on the photosensitive drum 1 is visualized as a toner image by one developing unit in the rotary developing device 100 disposed at the developing position.

As will be described in detail later, the rotary developing device 100 has a rotary body 300 rotatably attached to a rotary shaft 320, and a plurality of developing units 101, four in this embodiment, are mounted on the rotary body 300. ，
102, 103 and 104 are detachably attached. Of course, in the case of a red and black multicolor electrophotographic copier, two developer units would be sufficient.

In the full color electrophotographic copying machine shown in this embodiment, developing units 101, 102, 103
and 104 are a yellow developing unit, a magenta developing unit, a cyan developing unit, and a black developing unit, respectively. The black developing unit 104 may be omitted in some cases.

In the full color electrophotographic copier process,
The normal color image formation sequence is a yellow image, a magenta image, a cyan image, and finally a black image. Therefore, in the image forming process shown in FIG. 2, a blue filter is used as the color separation filter 11 to form an electrostatic latent image, and a yellow developing unit 101 is provided in the developing area 50.

The developing unit 101 is driven by a drive device 430 adapted to the present invention to perform a developing operation.

When the yellow image is developed in the developing unit 101, the photosensitive drum 1 carrying the yellow image is rotated to a transfer area where the transfer drum 5 is arranged.

The transfer drum 5 has grippers 51 on its circumferential surface. The gripper 51 is moved to a transfer material grip position 5 by a gripper cam 52 provided inside the transfer drum 5.
3, and is fed to the grip position 53 via the transfer material conveyance system 35 from, for example, one of the transfer material cassettes 31 and 32 arranged in the paper feeder 30. Grip the leading end of the transfer material P. Although the transfer material P can be made of any material, it is usually paper, so it will be referred to as transfer paper hereinafter. The transfer paper P is gripped by the gripper 51 and moves together with the transfer drum 5 in the direction of an arrow 54, clockwise in FIG. 2. At this time, the transfer paper P is held in close contact with the circumferential surface of the transfer drum 5 by the action of an adsorption charger 55 provided inside the transfer drum 5 and a presser roller 56 that is in contact with the circumferential surface of the transfer drum 5 . When the transfer paper P held on the transfer drum 5 in this manner is transferred to the transfer area 50, the yellow image formed on the photosensitive drum 1 in the manner described above is transferred to the transfer paper P. A transfer charger 57 is provided inside the transfer drum 1 .

After the yellow image has been transferred, the photosensitive drum 1
After the static electricity is removed by the static eliminator 61, the photosensitive drum 1 is cleaned by a cleaning device 6 having an elastic blade.
The residual toner on the top is removed. This completes the process of forming the yellow image of FIG. 2, and subsequently magenta, cyan, and black images are formed in the same manner as described above. However, when forming a magenta image, the green filter of the color separation filter 11 is used to irradiate the photosensitive drum 1 with a light image, and the magenta developing unit 102 is used for development. In other words, the developing device 1
00 indicates that after the previous yellow image development, the rotating body 300 rotates in the direction of arrow 105, counterclockwise in FIG.
A magenta developer unit 102 is located in development zone 40 and configured to develop the magenta electrostatic latent image. Similarly, when forming a cyan image, a red filter is used as the color separation filter 11, and a cyan developing unit 103 is used for development. When forming a black image, the color separation filter 11 is not used, but the black developing unit 104 is used.

The transfer drum 5 is passed through the transfer area 50 for each image formation while gripping the transfer paper P with the gripper 51, and the toner images of each color are transferred to the same transfer paper P.

After the final image has been transferred, the photosensitive drum 1 has its residual potential after transfer removed by a static eliminator 61, and then its surface is cleaned by a cleaning device, and then the photosensitive drum 1 is stopped or starts the next copying process.

On the other hand, when the transfer drum 5 finishes transferring the final black image onto the transfer paper P, the gripper 51 operates the gripper cam 58 provided in the transfer drum 5 to release the transfer paper P from the gripper 51. The released transfer paper P is separated from the transfer drum 5 by the separation claw 65 and sent to the transfer material conveyance system 25.
The transfer material conveyance system 25 may be any device that conveys the transfer paper P while sucking it, and usually includes a conveyance belt 26 and a suction means 27 . The transfer material P is fed to the fixing device 20 by a transfer material conveying system 25. The fixing device 20 includes a pair of fixing rollers 21 and 22.
The toner image on the transfer paper P is fixed onto the transfer paper by the pressure and heating action of the pair of fixing rollers 21 and 22. After that, the transfer paper P is placed in the tray 23.
is discharged upwards.

Next, the rotary developing device 100 will be explained.
As best illustrated in FIGS. 3 to 5, the rotary developing device 100 includes a rotating body 300 rotatably supported by a copying machine via a rotating shaft 320, and a rotary body 300 that is detachably attached to the rotating body 300. A plurality of developing units 101 to 104 are provided. Each developing unit basically has the same structure and shape, and its external appearance is shown in FIG. 5, and its cross section is shown in FIG. 6. Further, in FIG. 3, only the yellow developing unit 101 is illustrated, and the other developing units 1
02, 103 and 104 are shown removed, and FIG. 4 shows the rotating body 300 after all developing units have been removed.

First, the developing unit will be explained. Since each developing unit basically has the same structure and function as described above, only the yellow developing unit 101 will be described.

Rotary developing device 100, that is, each developing unit 1
01 to 104 use a two-component developer consisting of a toner based on a polyester resin containing dyes or pigments of each color and a carrier made of magnetic powder.

As can be seen with reference to FIGS. 6 and 7, the developer unit 101 includes a lower housing 112 defining a developer chamber 111 containing a developer D containing carrier and toner;
12 and an upper housing 114 defining a toner chamber 113 that stores replenishment toner for supplying toner consumed in the developing chamber 111. Lower housing 11
The upper housing 114 has a generally U-shaped cross section and an elongated shape extending in the width direction of the photosensitive drum 1, and the upper housing 114 has a generally mouth-shaped cross section.
Extends the same as 12. Both housings 112 and 114 are integrally stacked and have end members 115 and 116 at each end, as shown in FIG.
is installed.

The developing chamber 111 is divided into two chambers by a partition plate 117, that is, a first developing chamber 111a and a second developing chamber 1.
11b, each developing chamber 111a and 111
Developer stirring screws 118 and 119 are rotatably provided in b in a well-known manner. Also, partition plate 1
17, as best illustrated in FIG.
16, but a communication path 120 between both developing chambers 111a and 111b (the communication path on the end member 116 side, that is, on the back side of the developing chamber 111 is not shown) is formed. When the stirring screws 118 and 119 are driven in the manner described later, the developer D in the first developing chamber 111a is transferred from the back side of the developing chamber to the front side in the direction of arrow 121, and the developer D in the second developing chamber 111b is transferred. D is transported in the direction of arrow 122 from the front side to the rear side of the developing chamber. Front end screw 118 of stirring screw 118
a spirals in the opposite direction to the remaining screw, and the rear end screw (not shown) of the stirring screw 119 also spirals in the opposite direction to the remaining screw. Therefore, the developer D transferred to the front side of the first developing chamber 111a is continuously supplied to the second developing chamber 111b through the communication path 120, and is also transferred to the back side of the second developing chamber 111b. The developer D is also continuously supplied to the first developing chamber 111a in the same manner. That is, with the above configuration, the developer D in the developing chamber 111 is continuously circulated in the directions of arrows 121 and 122 through the first developing chamber 111a and the second developing chamber 111b. Due to such circulation movement, the toner and carrier in the developing chamber 111 are uniformly stirred and mixed, thereby eliminating variations in the concentration of the developer D in the developing chamber 111.

A developer carrying member, that is, a developing roller 130 in this embodiment, is arranged above the developing chamber 111, that is, the second developing chamber 111b in this embodiment. The developing roller 130 includes a magnet roller 131 rotatably disposed in the developing unit 101, and a non-magnetic sleeve roller 132 surrounding the magnet roller 131 and rotatably provided. Both rollers 131 and 132 are rotated in opposite directions; in this embodiment, sleeve roller 132 is configured to rotate clockwise as viewed in FIG. 6, and magnet roller 131 is configured to rotate counterclockwise. .

The developer D moving in the developing chamber 111, that is, the second developing chamber 111b, is pulled up toward the developing roller 130 by the magnetic force of the developing roller 130.
A so-called magnetic brush is formed on the circumferential surface of the sleeve roller 132. The developer attracted to the circumferential surface of the sleeve roller 132 moves clockwise while rotating as the sleeve roller 132 rotates, and the amount of spikes of the magnetic brush is regulated to a predetermined amount by the doctor blade 133, and the developer is developed. Toner is supplied onto the photosensitive drum 1 in area 40 (FIG. 2). The developer that supplied toner to the photosensitive drum 1 is supplied to the developing roller 13.
By the rotation of the developing roller 130 while being sucked into the developing chamber 111, that is, the second developing chamber 111.
b, and is scraped off from the circumferential surface of the sleeve roller 132 by the scraping blade 135. Opening amount 1 of the developing roller 130 to the developing area 40
34 is regulated by opening regulating plates 136 and 137. Further, the magnet roller 131 of the developing roller 130 is connected to the opening 1 of the developing roller 130, as described in Japanese Patent Publication No. 55-20579 filed by the present applicant.
34 is directed downward, a sufficient magnetic field is formed between the developing roller 130 and the opening regulating plates 136 and 137 so that the developer in the developing chamber 111 does not fall from the opening 134. Ru.

As described above, the toner chamber 113 is formed above the developing chamber 111, and stores toner for replenishment. From the toner chamber 113, an amount of toner equal to that consumed from the developing chamber 111 for development is supplied to the developing chamber 111 via a toner supply means 140.
In this embodiment, it is supplied to the first developing chamber 111a. Therefore, the developer D in the developing chamber 111
The concentration of is always kept constant.

Next, the overall structure of the rotary developing device 100, which is constructed by mounting a plurality of developing units, four in this embodiment, having the above-described structure will be described.

FIG. 3 shows a rotating body 300 carrying one developing unit 101, and FIG. 4 shows the rotating body alone. The rotating body 300 has a front plate 301 located on the front side when mounted on the copying machine main body.
and a rear side plate 302 located on the back side when attached to the copying machine main body. The front side plate 301 is
A center plate 303 having a roughly square shape in the center, and arms 305 protruding outward from the corners of the center plate 303.
It consists of A notch 306 is formed on each outer side of the center plate 303 for the purpose described later. Further, the outer end of each arm 305 is a head 307 expanded into a generally conical shape, and the outer periphery of the head 307 of each arm 305 is formed to form one virtual circle 308. Notches 307a and 307b are also provided on the sides of each head 307.

The rear plate 302 has the same shape as the front plate 301 and includes a center plate 313, arms 315, and arm heads 317, but notches 306 and 307 formed in the center plate 313 and arm heads 317 of the front plate 301.
There is no equivalent to a, 307b.

The front side plate 301 and the rear side plate 302 have a rotating shaft 320 disposed at the center and extending slightly protruding outward from the center plates 303 and 313 of both side plates;
They are integrally connected by four stay-like rails 321 arranged between the arm heads of both side plates. With this configuration, the rotating body has developing unit storage chambers 325a, 325b, 32 that can accommodate the four developing units 101, 102, 103, and 104.
5c and 325d are defined.

On both sides of each rail 321, there are guide grooves 32 connected to the notches 307a and 307b of the front side plate 301.
1a, 321b, 321c and 321d are formed, but these notches and guide grooves are formed by pins 210 and 211 (fifth
6) and guide the developing unit to each storage chamber of the rotating body 300.

A driving gear 330 is integrally fixed to the rear side plate 302, and as shown in FIG.
0 is inserted into the copying machine main body and the rotary shaft 320 is rotatably supported by the copying machine main body bearing (not shown), the rotating body driving means 400 appropriately provided in the copying machine main body is activated. configured to engage.

The rotational drive means 400 has an electric motor M1, and the rotational output of the electric motor M1 is transmitted from the motor output shaft gear 402 to the gears 403, 404, and 405.
is transmitted to the rotational drive gear 330 via. A rotary encoder 401 is directly connected to the electric motor M1, detects the rotational speed and amount of rotation of the rotating body 300, and controls the speed of each developing unit using a driver circuit (not shown).

Rear plate 302 of rotating body 300 and drive gear 33
0 or adjacent to these members, a developing unit driving means 430 for supplying driving force to the developing unit disposed at the developing position of the rotating body positioning device 420;
A means 450 connected to the developing unit for detecting various information in the developing unit, such as the developer concentration information and toner remaining amount information, and a driving force for sliding the shutter plate 142 of the toner supply means 140. Means 470 and rotating body 300 for
Means 380 and the like are provided for detecting the stop position of the motor.

As clearly shown in FIG. 8, the rotating body 300 has a positioning device 420 attached to a stopper member 331 fixed to the rear plate 302 or the drive gear 330.
The positioning pin 427 is engaged to determine the position. The stopper member 331 is an integral annular ring as shown in FIG. 8, and is engaged with the stopper pin 427 as necessary at a position corresponding to the stop position of the rotary body 300 along the arc of the rotary body 300. It can be configured to have an engagement groove 332 for doing so. Stoppa pin 42
7 is released by attracting the solenoid 425 against the spring 424.

Next, a developing drive device 430 suitable for the present invention will be described.

FIG. 1 shows the developing drive device 430 shown in FIG.
is an enlarged view of the developing unit 1 in the developing position.
01 drive input gear 221 and main drive device 430
The drive gear 461 shown in FIG.

The structure of the developing drive device 430 will be explained in more detail. This device 430 has side plates 460a and 4
60b and a connecting plate 460c connecting the side plates 460a and 460b, the housing 460 has a generally U-shaped cross section. The housing 460
is swingably mounted around a pivot shaft 456 fixed to the main body of the copying machine (not shown). A gear 457 is rotatably provided on the pivot shaft 456.

A shaft 458 is rotatably provided in the housing 460 at a position spaced apart from the pivot shaft 456 . A gear 459 and the aforementioned drive gear 461 are fixed to the shaft 458, and the gear 459 is engaged with the gear 457, and the gear 461 is engaged with the drive input gear 221 of the developing unit as described above. Therefore, it will be understood that gear 459 and gear 457 are in the relationship of a planetary gear and a sun gear.

Although the housing 460 is biased by the action of the spring 463 so that the drive gear 461 moves toward the input gear 221, the amount of rocking of the housing 460 is restricted by the side plate 456 coming into contact with the pin 462. That is, before the drive gear 461 meshes with the input gear 221 of the developing unit 101, the side plate 456 is in contact with the pin 462, and the housing 46 is in contact with the pin 462.
0 is stationary in this state. Also, drive gear 461
When the input gear 221 and the input gear 221 are engaged, the side plate 460b of the housing comes into contact with the rollers 223 rotatably provided on the shaft 224 of the input gear 221, and both gears 46
The center-to-center distance between 1 and 221 is maintained at an appropriate amount.

Further, the developing drive device 430 includes a gear 4 rotatably provided on a shaft 453 fixed to the main body of the copying machine.
55, and a belt pulley 454 is integrally connected to the gear 455. The belt pulley 4
54 and a belt pulley 451b attached to the output shaft 451a of the drive motor M2, a timing belt 452 is stretched, and the output rotation of the drive motor M2 is transmitted via the timing belt 452 to the pulley 454→gear 455→ Gear 457 → Gear 459
and 461, and then to the developing unit 10.
It is transmitted to the drive input gear 221 of No. 1. The rotational force of the drive input gear 221 is transmitted through the gears 222, 225 and 2.
26 to drive the developing roller 130 or to drive the stirring screws 118 and 119.

At this time, since the motor M2 is in the direction of arrow A, the rotation directions of the drive gear 461 and input gear 221 are in the direction of arrows B and C, and therefore both middle drive gears 4
A rotational moment acts on the gears 61 and 221 in the biting direction about the pivot shaft 456, so that the gear 461 does not disengage from the input gear 221 during driving.

Furthermore, a one-way clutch 451c is interposed between the output shaft 451a of the drive motor M2 and the belt pulley 451b. The one-way clutch 451c connects the output shaft 451a and the belt pulley 4 when the output shaft 451a rotates in the direction of arrow A.
51b rotate together and can freely rotate in the opposite direction.

The center of rotation of the rotary developing device is located at point O as schematically shown in FIG. state). The developing drive device 430 is connected to the developing unit 1 as described above.
Before meshing with the input gear 221 of 01,
The housing 460 is positioned in contact with the stopper pin 462, and therefore the position of the drive gear 461 is slightly closer to the center O than when it is engaged with the developing unit. When the developing unit 101 rotates in the direction of arrow D, the input gear 221 first contacts the waiting drive gear 461 from the lower left side in FIG. 1, and rotates the drive gear 461 in the direction of arrow B to the developing position. Coming in. At this time, since the one-way clutch 451c is present, the rotor and gear head of the motor M2 are not rotated, and the belt pulley 451c is not rotated.
Since the drive gear 461 rotates around the motor output shaft 451a, the drive gear 461 can rotate with the input gear 221 of the developing unit. The one-way clutch 451c is connected to the developing unit 10.
Although it is also possible to insert it between the one input gear 221 and the input shaft 224, it is necessary to provide it for each developing unit. Further, the clutch 451c is connected to the shaft 45
However, in this embodiment, the clutch 451c is placed on the upstream side of the drive transmission path to prevent biting caused by the meshing of the gear 221 and the gear 461 from being caused by backlash from the gear 455 to the gear 461. This is to release it.

Although the clutch 451c described above is a so-called one-way clutch that allows rotation in only one direction, the clutch 451c may be electrically or mechanically controlled as desired to prevent rotation between the electric motor M2 and the drive gear 461. It can be a clutch that can disconnect or connect the driving force.

When one developing process is completed, the rotary developing device is rotated in the direction of arrow D to perform another developing process.
As a result, the developing unit 101 rotates in the direction of arrow D, and the gear 221 is disengaged from the drive gear 461.

Effects of the Invention According to the present invention, there is provided a color image forming apparatus in which required developing units are moved to one developing position common to each color, and the driving means is also provided as one common developing position for each developing unit. Since the driving force is applied only at the developing unit, the structure of the developing unit can be simplified and the structure of the device can be downsized, and each developing unit can be smoothly engaged with the driving means when it reaches the developing position. Therefore, damage to the device can be prevented and the developer carrying member can be driven smoothly, contributing to improved image quality. Further, even if the position of the drive input gear varies slightly due to variations in the precision of parts of each developing unit, this can be absorbed.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a developing drive device adapted to the present invention. FIG. 2 is a schematic cross-sectional view of a full-color electrophotographic copying machine showing an embodiment of the present invention.
FIG. 3 is a perspective view of the rotary developing device. FIG. 4 is a perspective view of the rotating body. FIG. 5 is a perspective view of the developing unit. FIG. 6 is a sectional view of the developing unit of FIG. 5. 7 is a partial schematic perspective view showing the inside of the developing unit shown in FIG. 5. FIG. FIG. 8 is a perspective view of the rotary developing device viewed from the rear side plate. FIG. 9 is a schematic explanatory diagram showing the configuration of the developing drive device shown in FIG. 1. 100: Rotary developing device, 101, 102, 10
3,104: Developing unit, 221: Drive input gear, 430: Developing drive device, 451a: Motor output shaft, 451c: One-way clutch, 460:
Housing, 461: Drive gear.

Claims (1)

[Scope of Claims] 1. An image carrier; a latent image forming means for forming an electrostatic latent image corresponding to each color image on the image carrier; and a developer for carrying and conveying a developer and applying it to the image carrier. A plurality of developing units each having a developer carrying member and a drive input gear that receives a driving force for driving the developer carrying member, each of which applies developer of a different color to an image carrier. a movable support that supports the plurality of developing units and is movable along a predetermined path so as to move the required developing units to one developing position common to each color; A drive means having a drive gear that engages with a drive input gear of a developing unit to transmit a driving force, the drive means being swingably provided on a pivot fixed at a predetermined position along the movement path of the movable support. a swinging member that supports the drive gear;
an elastic member that urges the swinging member so that the drive gear enters the movement locus of the drive input gear of the developing unit as the movable support moves;
a first regulating member that locks the swinging member when the drive input gear of each developing unit is not engaged with the drive input gear to regulate the amount of entry of the drive gear into the drive input gear movement locus; a driving means having;
Each of the developing units has a second regulating member that locks the swinging member when the drive input gear and the drive gear are engaged to regulate the distance between the centers of the two gears. A color image forming device. 2. The device according to claim 1, wherein the drive means includes an electric motor, and a one-way clutch rotatable in only one direction is provided in the drive transmission path from the electric motor to the drive gear. 3. The device according to claim 1, wherein the drive means includes an electric motor, and a clutch for connecting and disconnecting the drive force in the drive transmission path from the electric motor to the drive gear.