JP2002328503A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary type developing device where a plurality of developing units are mounted in the peripheral direction of a rotating body, and where toner is sufficiently and uniformly electrified, sufficient density is maintained and a fogging phenomenon caused by insufficient electrification is prevented from occurring by actuating the developer stirring and carrying member of the developing unit when the developing unit does not exist at an ordinary developing position. SOLUTION: In this developing device, a plurality of developing units in which two-component developer is stored are disposed in the peripheral direction of the rotating body, and the rotating body is rotated so that the desired developing unit is moved to a developing position opposed to an image carrier and develops an electrostatic latent image formed on the image carrier. Each developing unit is equipped with the developer stirring and carrying means for carrying the two-component developer while stirring it, and is constituted so that the developer stirring and carrying means can be driven at a position other than the developing position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used for an image forming apparatus such as an electrophotographic copying machine or a printer, and more particularly to a developing device using a two-component developer.

[0002]

2. Description of the Related Art Conventionally, as a developing device used in an image forming apparatus such as an electrophotographic copying machine or a printer of this type, a developing device using a one-component developer consisting only of toner and a magnetic particle are used. Some use a two-component developer composed of a carrier and a toner. In a developing device using such a two-component developer, it is necessary to sufficiently frictionally charge the toner by transporting the carrier and the toner while sufficiently stirring the toner inside the developing device.

In a developing apparatus using the above-described two-component developer, a technique for sufficiently agitating the developer to eliminate uneven toner concentration and insufficient charging is disclosed in Japanese Patent Application Laid-Open No. 2-18583.
Some are already disclosed in Japanese Patent Publication No. The developing device disclosed in Japanese Patent Application Laid-Open No. 2-18583 is a developing device in which a two-component developer is subjected to development on the way while being stirred and transported in a circulation path. It is configured to have control means for continuing the movement of the section.

[0004]

However, the prior art described above has the following problems. That is, in the case of the developing device disclosed in Japanese Patent Application Laid-Open No. 2-18583, in a developing device which performs development while stirring and transporting a two-component developer in a circulation path, the developing operation is performed for a predetermined time at the end of the developing operation. Although it is configured to include a control unit that continues the movement of the transport unit at a lower speed, in the case of a rotary developing device equipped with a plurality of developing units along the circumferential direction of the rotating body, Since the developing device is configured to be rotationally driven only at the developing position, the developing device cannot be operated at the end of the developing operation, and the toner is insufficiently charged to generate a toner cloud, There is a problem that a sufficient development density cannot be obtained.

[0005] In the case of a rotary developing device having a plurality of developing devices mounted along the circumferential direction of the rotating body as described above, each developing device is configured to be driven to rotate only at the developing position. Therefore, there is a problem in that the history of the development nip generated in the previous development process is generated in the next development process as streaky density unevenness at the leading end on the copy.

More specifically, in the case of the rotary type developing device, since each developing device is configured to be rotationally driven only at the developing position, the developing process is completed and the developing device is moved to the developing position. , The rotation of the developing roll is immediately stopped. Therefore, at the end of the development process,
In particular, in the case where a high-density image is developed, in the developing nip portion where the photosensitive drum and the developing roll face each other, the toner density on the developing roll extremely decreases. Then, in the next development step, since the developing roll in which the toner concentration has decreased faces the development nip area, the development history in which the toner concentration has decreased appears as streak-like density unevenness at the leading end on the copy. Had the problem that

In order to solve such a problem, the development history is not changed until the switching of the developing device is completed during the inter-image time and the electrostatic latent image on the photosensitive drum reaches the developing position. It is sufficient if the developing sleeve can be rotated to such an extent that the development can be eliminated.However, when the process speed of the image forming apparatus is increased, sufficient time for rotating the developing sleeve cannot be taken until the development history can be eliminated. It has been difficult to reliably prevent development history from occurring.

Accordingly, the present applicant uses a swinging pendulum gear as a gear for rotationally driving the developing sleeve, and transmits a driving force to the developing sleeve from just before the developing position to start rotation of the developing sleeve. The configured technology has already been proposed in Japanese Patent Application Laid-Open No. 6-195069.

However, in the case of the technique disclosed in Japanese Patent Application Laid-Open No. 6-195069, the gear for driving the developing sleeve to rotate needs to be a swinging pendulum gear, which complicates the structure and causes the mounting. In addition to increasing the space, if the switching speed of the developing device is set high, the relative position change of the developing device side gear (driven gear) with respect to the driving side gear of the developing sleeve is fast, and the rotation of the driving side gear can follow. Therefore, there is a problem that the rotation drive may not be transmitted, and the development history may not be able to be surely eliminated.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a rotary system in which a plurality of developing units are mounted along a circumferential direction of a rotating body. In the developing device of (1), when the developing device is not in the normal developing position, by operating the developer stirring and conveying member of the developing device, the toner can be charged sufficiently and uniformly, and a sufficient density can be maintained. It is another object of the present invention to provide a developing device which can perform a fogging phenomenon due to insufficient charging while preventing fogging.

Another object of the present invention is to provide a rotary type developing apparatus having a plurality of developing units mounted along a circumferential direction of a rotating body, in which a developing history is generated with a simple configuration. An object of the present invention is to provide a developing device capable of reliably preventing the developing device.

[0012]

According to a first aspect of the present invention, there is provided an image forming apparatus comprising: a plurality of developing devices accommodating a two-component developer disposed along a circumferential direction of a rotating body; And
A developing device that rotates the rotator to move a desired developing device to a developing position facing the image carrier, and develops the electrostatic latent image formed on the image carrier by the desired developing device. Each of the developing devices includes a developer stirring and conveying unit that conveys the two-component developer while stirring, and each of the developing devices is configured to be able to drive the developer stirring and conveying unit at a position other than the developing position. Is a developing device.

Further, the invention described in claim 2 is the developing device according to claim 1, wherein each of the developing devices does not drive the developer carrier at a position other than the developing position.

Further, in the invention described in claim 3, the position of each of the developing devices other than the developing position is substantially one distance from the developing position.
3. The developing device according to claim 1, wherein the developing device is at a position rotated by 80 degrees.

[0015] Still further, the invention described in claim 4 is:
A plurality of developing devices containing a two-component developer are disposed along the circumferential direction of the rotating body, and the rotating body is rotated to move a desired developing device to a developing position facing the image carrier, In a developing device for developing an electrostatic latent image formed on an image carrier with a two-component developer carried on a developer carrier of a desired developing device, the developer carrier of each of the developing devices is rotated. A driven gear for driving, and a gear for preliminary rotation that meshes with a driven gear for rotationally driving the developer carrier at a position immediately before the rotating body rotates and the developing device reaches the developing position. When the developing device is moved to the developing position, a driven gear for rotationally driving the developer carrier is meshed with a gear for preliminary rotation in a fixed state, so that the developer carrier is moved by a predetermined amount. Development characterized by pre-rotation only It is the location.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a sectional view showing a rotary type developing device as a developing device according to Embodiment 1 of the present invention.

This rotary type developing device 1 is shown in FIG.
As shown in FIG. 4, four developing units 2Y, 2M, 2C, and 2K of yellow (Y), magenta (M), cyan (C), and black (K) containing a two-component developer are arranged around the rotating body 3. The developing unit 2Y, 2M, 2C, 2K is moved to a developing position facing a photosensitive drum 4 as an image carrier by rotating the rotating body 3; The electrostatic latent image formed on the photosensitive drum 4 is developed by a desired developing device. The rotary type developing device 1 includes a rotating body 3 that can rotate clockwise around a rotating shaft 5 located at the center thereof. The rotating body 3 includes a central portion 6 to which the rotating shaft 5 is attached, and four arm portions 7 extending substantially radially from the central portion 6 and provided at an angle of 90 degrees with each other. ing. Four developing units 2Y, 2M, 2C, 2K for yellow (Y), magenta (M), cyan (C), and black (K) are attached to the arm unit 7 of the rotating body 3 by mounting means (not shown). Has been implemented.

These developing units 2Y, 2M, 2C, 2K
Are all configured in the same way,
In the following description, the yellow (Y) developing device 2Y located at the developing position will be described as an example.

As shown in FIGS. 1 and 2, a predetermined amount of a two-component developer 13 composed of a carrier and a toner is accommodated in the main body 8 of the developing device. Further, inside the developing device main body 8, a developer carrier as a developer carrier disposed along a length in a direction perpendicular to the paper surface so as to partially expose the outer peripheral surface of the rotating body 3. A developing roll 9 and two developer agitating / conveying augers 10 and 11 as developer agitating / conveying members located on the back side of the developing roll 9 and extending parallel to the developing roll 9 are provided. Inside the developing roll 9, a magnet roll 12 having a magnetic pole of a predetermined polarity disposed at a predetermined position is fixedly disposed. Here, when the developing roll 9 rotates, as shown in FIG. 3, the developer stirring and conveying auger 11 conveys the developer 13 contained in the developing device main body 8 while stirring in one direction. is there. The other developer agitating / conveying auger 10 conveys the developer 13 while stirring it in a direction opposite to the conveying direction of the developer agitating / conveying auger 11, and uniformly supplies the developer 13 to the developing roll 9. Is what you do. A developer accommodating section 14 for accommodating the developer 13 is provided below the developer agitating and conveying auger 10 inside the developing device main body 8. The developer accommodating portion 14 is accommodated in the developing device main body 8 by reducing the size of the developing device 2 and increasing the amount of the developer 13 accommodated in the developing device main body 8 to some extent. This is for making the concentration of the developer 13 more uniform and stable. However, when the developing device 2 is located at the developing position, as shown in FIG.
The developer 3 is not agitated and transported by the developer agitation transporter 10 and does not directly contribute to development.

The developing roll 9 magnetically attracts the carrier contained in the developer 13 by means of a magnet roll 12 disposed inside the developing roll 9, and the developer 1 is applied to the surface of the developing roll 9.
The magnetic brush of No. 3 is formed, and the toner adsorbed on the carrier is conveyed to a developing area facing the photosensitive drum 4. The electrostatic latent image formed on the photoconductor drum 4 is visualized by a magnetic brush of a developer 13 formed of a carrier and toner formed on the surface of the developing roll 9.

Inside the developing device main body 8, a cylindrical casing 15 provided above one developer agitating and conveying auger 11 and a spiral auger 16 provided inside the casing 15 are provided. A new developer is supplied at a predetermined timing from a developer cartridge (not shown) provided outside the developing device 1. The cylindrical casing 15 is provided at an upper portion on the back side of the developing device 2. In the casing 15,
A spiral auger 16 is provided, and the new developer 13 supplied from a developer cartridge (not shown) is guided by the spiral auger 16 to a supply port (not shown) provided on the upper surface on the rear side of the developing device 2. Then, it is supplied into the developing device main body 8. At the outlet located at the lower end of the supply port of the developing device main body 8, a flap (not shown) is provided so as to be openable and closable, and is open when the developing device 2Y is at the developing position D in FIG. On the other hand, the flap is
When Y is at the position F or the position G in FIG. 1, it is closed by its own weight.

In the developing device 2, a part of the developer 13 contained in the developing device main body 8 is recovered at a predetermined timing, and a new developer is supplied, so that the developer can be made longer. You may comprise so that life may be extended.

In the rotary developing device 1 having the developing devices 2M, 2C, and 2K configured similarly to the developing device 2Y configured as described above, the developing device 2 is located at a developing position where the developing device 2 faces the photosensitive drum 4. At the position D, the flap (not shown) has its supply port opened by its own weight, and the spiral auger 16 is driven to rotate so that the new developer 13 is replenished into the developing device 2 as needed. You. Then, the development of the electrostatic latent image on the photosensitive drum 4 by the developing device 2 is completed,
When the rotating body 3 rotates clockwise and the developing device 2 moves from the position D to the position E at the lower right, the flap (not shown) is opened halfway, the recovery port faces upward, and is conveyed by a discharge pipe (not shown). The old developer does not flow back into the developing device 2 but flows toward a collection passage (not shown). The deteriorated developer is recovered to a deteriorated developer recovery section (not shown) through the recovery path until the developing device 2 reaches the lower left F position to the upper left G position.

On the other hand, while the developing device 2 is moving from the upper left position G to the right side developing position D again, the developer auger (not shown) is fed by a spiral auger 16 in the casing 15 to a supply port (not shown). It is led.
At this time, since the flap has opened the supply port again, the new developer 13 is supplied into the developing device main body 8 through the supply port.

In this embodiment, each of the developing devices includes a developer agitating / conveying means for conveying the two-component developer while agitating the two-component developer, and each of the developing devices is provided at a position other than the developing position. The agent stirring and conveying means is configured to be drivable.

In this embodiment, each of the developing devices is configured not to drive the developer carrier at a position other than the developing position.

Further, in this embodiment, the position other than the developing position of each of the developing units is configured to be a position rotated by about 180 degrees from the developing position.

4 and 5, reference numeral 20 denotes a frame of the main body of the image forming apparatus (for example, a copying machine).
A developing device driving clutch 22 is attached to a bracket 21 of the apparatus main body frame 20.
The driving force is transmitted via a belt 23 from a main drive motor that drives the photosensitive drum 4 and the cleaner. In the clutch 23, the drive shaft 2 supported by the bearing 24 on the apparatus body frame 20 is provided.
The driving force is transmitted to the driving shaft 25 by turning on and off the clutch 23. Drive shaft 2
5, a developing device driving gear G0 for driving the developing device 2 located at the developing position is fixedly attached. The developing device driving gear G0 has a driven gear G3.
Are configured to be meshable. The driven gear G3 is supported by a support shaft 27 via a bearing 26,
7 is fixed to a bracket 28 attached to the rotating body 7.

In FIG. 3, a mechanism for driving the developing device in the non-development position, which is a component of the present invention, is omitted for easy understanding.

The rotation of the third driven gear G3 is performed by the driven gear G4, the developing roll driving gear G5, the driven gear G6,
An auger drive gear G7 for developer stirring and conveyance, a driven gear G8,
The developer agitating and conveying auger drive gear G9 is transmitted in this order,
By the rotation of these gears, the developing roll 9 and the two developer agitating and conveying augers 10 and 11 in FIG. 1 can be rotated.

FIG. 6 is a diagram for explaining the operation timing of the rotary developing device having the above configuration, and FIG. 7 is a schematic diagram for explaining the operation. When the drive motor of the rotating body 7 is turned on / off in FIG. 5, the rotating body 7 moves the predetermined developing device 2 to the developing position and stops as shown in FIG. 5, and after the development is completed, moves the next developing device 2 to the developing position. Repeat the movement. At this time, the developing device driving clutch 22 is turned on at y2 immediately before the rotating body 7 rotates and the developing device 2 reaches the developing position, and x2 immediately after the next rotational movement from the developing position. To turn it off.

When the developing device driving clutch 22 is turned on, as shown in FIG. 7, the developing device driving gear G0 starts to rotate, and the developing device driving gear G0 causes a rotational force to be applied to the driven gear G3. The driving force is transmitted to the developing device 2 via the third driven gear G3, and the developing roller 9 and the two developer agitating and conveying augers 10 and 11 are rotationally driven to perform the developing operation. Will be

In this embodiment, as shown in FIG. 3, the developing units 2Y, 2M, 2C, and 2K are set at positions other than the developing position, that is, at F different from the developing position D by 180 degrees.
In the position (1), the developer agitating / conveying augers 10 and 11 of the developing units 2Y, 2M, 2C and 2K can be driven to rotate by a predetermined amount.

At a position F which is different from the developing position D by 180 degrees, as shown in FIG. 8, a mechanism similar to a mechanism for rotating and driving a developing roll or the like at the developing position is provided. Thus, the developer agitating and conveying augers 10 and 11 of each developing device are configured to be rotationally driven.

That is, at a position F which is different from the developing position D by 180 degrees, as shown in FIG. 8 and FIG. A driving force is transmitted to the clutch 32 via a belt 33 from a main drive motor that drives the photosensitive drum 4 and the cleaner. In the clutch 32, a drive shaft 35 supported by a bearing 34 on the apparatus body frame 20 is provided.
The driving force is transmitted to the driving shaft 35 by turning on and off the clutch 32. Drive shaft 35
A fixedly attached developing device drive gear G10 for driving the developing device 2 located at the developing position is attached to the leading end of the developing device drive gear G10.
13 are configured to be meshable. Driven gear G13
Is supported by a support shaft 37 via a bearing 36, and the support shaft 37 is attached to a bracket 38 attached to the rotating body 7.
It is fixed to.

The rotation of the thirteenth driven gear G13 is opposite to the developing position, and the developer agitating / conveying auger driving gear G9, the driven gear G8, the developer agitating / conveying auger driving gear G7, the driven gear G6, The development roller drive gears G5 are transmitted in this order, and the rotation of these gears allows the two developer agitating and conveying augers 10 and 11 of FIG. 1 to be rotatable at a non-development position for a desired time.

At this time, a one-way clutch (not shown) is interposed in the developing roll driving gear G5 for rotatingly driving the developing roll 9, and at a developing position where the driving force is transmitted from the driven gear G4 to the developing roll 9, The developing roller 9 is configured to be rotationally driven in a predetermined direction, and conversely, to inhibit the rotation of the developing roller 9 in a non-developing position where the driving force is transmitted from the driven gear G6 to the developing roller 9. ing. With this configuration, the developer roll 9 is unintentionally rotated at the non-development position, and the developer 1
3 can be prevented from being accelerated.

In the above-described configuration, the developing device according to this embodiment is a rotary type developing device in which a plurality of developing devices are mounted along the circumferential direction of the rotating body as described below. By operating the developer agitating and conveying member of the developing device when the developing device is not at the developing position,
The toner can be charged sufficiently and uniformly, a sufficient density can be maintained, and a fogging phenomenon due to insufficient charging can be prevented.

That is, in the developing device 1 according to this embodiment, as shown in FIG. 8, at a position F which is different from the developing position D by 180 degrees via the second developing device driving clutch 32 at a predetermined timing. Then, the driving shaft 35 is rotationally driven by the belt 33, and the developing device driving gear G10 attached to the driving shaft 35 is rotationally driven. Then, as shown in FIG. 9, a thirteenth driven gear G13 provided on the rotating body 7 meshes with the developing device driving gear G10 at a position F different from the developing position D by 180 degrees, as shown in FIG. The torque of the tenth drive gear G10 is transmitted to the thirteenth driven gear G13. And the first
As shown in FIG. 8, the driven gear G13 of the developing device 1
, The driven gear G8, the developer agitated and transported auger drive gear G7, and the driven gear G6 through the developer agitated and transported auger drive gear G9. , Developing roll drive gear G
5, the rotation driving force is sequentially transmitted, and the rotation of these gears causes the two developer agitating / conveying augers 10, 1 in FIG.
1 is driven to rotate for a desired time in the non-development position.

As a result, when the developing device 2 is not in the normal developing position, the developer agitating and conveying auger 1
By rotating 0 and 11, the toner can be charged sufficiently and uniformly, and a sufficient density can be maintained, and the fogging phenomenon due to insufficient charging can be prevented. It is possible.

As described above, in the above-described embodiment, as shown in FIG.
When the developer unit 2 is on the opposite side of 0 degrees, the developer 13 is in a state of being turned upside down, so that the developer 13 that could not be agitated and transported by the developer agitating and transporting augers 10 and 11 at the developing position is
The developer is moved to an area where the developer can be stirred and conveyed by the augers 10 and 11 for stirring and conveying. The position at which the developing device 2 is rotationally driven in the non-development position is not limited to the side opposite to the development position by 180 degrees, but may be another position.

In this state, the developer agitating and conveying auger 1
By operating 0 and 11, at the developing position in the developing device 2, the developer 13 that cannot be stirred and transported by the developer agitating and transporting augers 10 and 11 is mixed. As a result, the toner concentration difference in the axial direction of the developing device between the developer on the developing roll 9 and the developer 13 agitated and transported by the developer agitating and transporting augers 10 and 11 immediately after the development is completed is reduced. Is done. In addition, this operation can prevent non-uniform charging of the toner.

FIGS. 10 and 11 show the difference between the toner density of IN / OUT of the developing device at the non-developing position when continuous printing of an image with 70% area coverage is performed on A4 size paper. FIG. 10 is a graph showing experimental results when the developer agitating / conveying augers 10 and 11 were operated for 0.9 seconds to execute the agitation mode, and when the agitation mode was not implemented.

As is clear from these graphs, when the stirring mode is performed, the IN / OU of the developing device is used.
The difference in the toner concentration of T is substantially constant at about 0.05 to 0.08, but when the stirring mode is not performed, the IN / IN of the developing device increases as the number of prints increases. It can be seen that the density difference of the toner density of OUT gradually increases and rises to about 0.25 to 0.23.

Second Embodiment FIG. 12 shows a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals and described. A plurality of developing devices containing the two-component developer are arranged along the circumferential direction of the rotating body,
By rotating the rotator, a desired developing device is moved to a developing position facing the image carrier, and the electrostatic latent image formed on the image carrier is placed on the developer carrier of the desired developing device. In a developing device for developing with a two-component developer carried, a driven gear for rotationally driving a developer carrying member of each of the developing devices is provided, and immediately before the rotating member rotates and the developing device reaches a developing position. At a position, a gear for preliminary rotation is provided which meshes with a driven gear for rotationally driving the developer carrier, and for rotating the developer carrier when the developing device moves to the developing position. Is engaged with a gear for preliminary rotation in a fixed state, so that the developer carrier is preliminarily rotated by a predetermined amount.

FIG. 12 is a schematic configuration diagram showing a developing device according to the second embodiment of the present invention. The developing device according to the second embodiment has basically the same configuration as the developing device according to the first embodiment. However, in FIG. Is shown partially differently.

A developing roll driving gear G5 for rotating and driving the developing roll 9 of each developing unit 2 is attached to the rotating body 7 of the developing device 1, and the developing roll driving gear G5 is necessary. Accordingly, the driven gear G4 is meshed. A drive gear G0 for driving the developing device 2 is attached to the frame 20 on the apparatus main body side, and a driven gear G0 also attached to the frame 20 on the apparatus main body side is attached to the drive gear G0. G1 is configured to mesh with each other. The driven gear attached to the frame 20 on the apparatus main body side is configured to perform a pendulum motion over a predetermined angle.

In order to configure the driven gear attached to the frame 20 on the apparatus main body side to perform a pendulum motion over a predetermined angle, for example, the following means is adopted.

Referring to FIGS. 13 and 14, a developing device driving clutch 22 is mounted on a bracket 21 of the apparatus main body frame 20, and a main driving motor for driving the photosensitive drum 4 and a cleaner is attached to the clutch 22. The driving force is transmitted via the belt 23. In the clutch 23, a bearing 24 is mounted on a device (eg, copying machine) body frame 20.
The drive shaft 25 supported by is inserted.
The driving force is transmitted to the drive shaft 25 by turning on and off the clutch 23. A developing device drive gear G0 is fixed to the tip of the drive shaft 25. A first driven gear G1 meshes with the developing device drive gear G0.
The first driven gear G2 meshes with the first driven gear G1, and the third driven gear G3 can mesh with the second driven gear G2.

These driven gears G1, G2, G3 are respectively mounted on bearings 43, 44,
It is rotatably supported via 45. One end of the support shaft 40 of the first driven gear G1 is fixed to the apparatus body frame 20, and a bracket 46 is swingably fitted to the other end of the support shaft 40. The support shaft 41 of the second driven gear G2 is fixed to the bracket 46, and a gap setting spacer 47 is fixed to the other end of the support shaft 41. The support shaft 42 of the third driven gear G3 is fixed to a bracket 48 attached to the rotating body 7, and an end of the bracket 48 can be brought into contact with a gap setting spacer 47. The rotation of the third driven gear G3 is performed by the driven gear G4, the developing roll driving gear G5, the driven gear G6, the developer stirring / conveying auger driving gear G7, the driven gear G8, and the developer stirring / conveying auger driving gear G9. The rotation of these gears makes it possible to rotate the developing roll 9 and the two developer agitating and conveying augers 10 and 11 in FIG.

FIG. 15 is a diagram for explaining the operation timing of the rotary developing device having the above configuration, and FIG. 16 is a schematic diagram for explaining the operation. When the drive motor of the rotating body 7 is turned on and off in FIG. 15, the rotating body 7 moves the predetermined developing device 2 to the developing position and stops as shown in FIG. 15, and after the development is completed, moves the next developing device 2 to the developing position. Repeat the movement. At this time, the developing device driving clutch 22 is turned on at y2 immediately before the rotating body 7 rotates and the developing device 2 reaches the developing position, and x2 immediately after the next rotational movement from the developing position. To turn it off.

The above operation will be described in detail with reference to the drawings. In FIGS. 14 and 16A, a bracket 46 supporting the second driven gear G2 is swingably supported by a support shaft 46 of the first driven gear G1, and the bracket 46 includes:
A pin 49 on the device body frame 20 side and a spring 50 suspended on the support shaft 40 urge the device clockwise in the figure.

As shown in FIG. 16A, when the rotating body 7 rotates in the direction indicated by arrow A, the third driven gear G3 for driving the developing device 2 rotates about the center P of the rotating body 7. Immediately before reaching the developing position (the dotted circle in the figure),
The driven gear G3 is engaged with the second driven gear G2, and the developing device driving clutch 22 is turned on, and the driving force is transmitted to the developing device 2 via the developing device driving gear G0 and the driven gears G1, G2, G3. You. At this time, the second driven gear G2
When the driven gear G3 is driven, the gap setting spacer 47 mounted coaxially with the second driven gear G2 comes into contact with the bracket 48 supporting the third driven gear G3 to transmit the driving force.

Next, as shown in FIG.
When the driven gear G3 rotates to reach the developing position, the second driven gear G2 supported by the bracket 46 swings around the support shaft 40 in the direction indicated by arrow B against the spring 50. As shown in FIG. 16 (C), the meshing between the third driven gear G3 and the second driven gear G2 is maintained until immediately after the third driven gear G3 rotates and leaves the developing position. . When the third driven gear G3 and the second driven gear G2 are disengaged from each other, the second driven gear G2 returns to the original position by the bias of the spring 50.

As shown in FIG. 12A, the driven gears G1 and G2 on the side of the apparatus main body frame 20 move when the developing devices 2 are moved to a position immediately before the developing position by a predetermined angle. It is arranged so as to mesh with the driven gear G3 on the developing device 2 side. Then, the frame 20 on the apparatus body side
The driven gears G1 and G2 on the side rotate when the rotating body 7 to which the developing device 2 is attached rotates in the clockwise direction and the developing device 2 moves to a position immediately before the developing position by a predetermined angle. The outer periphery of the driven gear G2 on the side of the apparatus main body frame 20 in a stopped state meshed with the driven gear G3 on the developing device 2 side,
When the driven gear G3 on the developing device 2 rotates, the driven gear G3 on the developing device 2 rotates by a predetermined amount. At this time, the driven gear G2 on the apparatus body frame 20 side is configured to swing as shown in FIG.

In this state, the apparatus body frame 20
The drive gear G0 on the side is in a state where the developing device driving clutch 22 is in an off state and is not driven, and is stopped. Therefore, the driving gear G0 and the driven gears G1 and G2 meshing with the driving gear G0 are connected to the developing device driving clutch 22.
The stop state is maintained by the holding force of the stop state possessed by.

The driving gear G0 on the side of the apparatus main body frame 20 includes a belt 23 and a developing device driving clutch 22.
Instead of being driven to rotate by transmitting a driving force via the motor, the motor may be directly driven to rotate by a drive motor.

In any case, in this embodiment, the holding torque when the developing device driving clutch 22 is stopped and the holding torque when the driving motor is stopped are controlled by the developing roll 9 of the developing device 2 and the developer stirring and conveying. The driving torque for rotating the augers 10 and 11 is set to be larger than the driving torque, and the torque for driving the rotating body 7 is set to have a sufficient margin. As a result, the developing device drive clutch 22 and the drive motor (not shown) are in a state where the drive gear G0 driven by the developer drive clutch 22 and the drive motor (not shown) is stopped until the drive is started. The driven gears G1 and G2 meshing with the drive gear G0 are
Even when the driven gear G3 meshes with the driven gear G0, the driven gears G1 and G2 meshed with the driven gear G0 remain stopped without rotating even when the driven gear G3 of the developing device 2 is being moved to the developing position.
In addition, the driven gear G3 of the developing device 2 meshing with the driven gears G1 and G2 can be rotated by a predetermined amount.

In the above-described configuration, the developing device according to the second embodiment has a simple configuration in a rotary developing device in which a plurality of developing devices are mounted along the circumferential direction of the rotating body as follows. Thus, it is possible to reliably prevent the development history from occurring.

That is, in the developing device according to the second embodiment, as shown in FIG. 12 (a), for example, the developing device 2K for black (K) starts moving to the developing position, and this black (K) When the developing device 2K moves to a predetermined position just before the developing position, as shown in FIG. 12B, the driven gear G3 provided in the black (K) developing device 2K
Is a driven gear G2 provided on the apparatus body frame 20 side.
And become in a state of being engaged. In this state, since the drive gear G0 on the apparatus body frame 20 side is not driven,
Driven gears G2, G1 meshing with the drive gear G0
Is also stopped.

Then, the black (K) developing device 2K
12 is engaged with the driven gear G2 provided on the apparatus body frame 20 side.
As shown in (c), the rotation of the rotating body 7 causes the developing device 2 to rotate.
When K further rotates toward the developing position, the driven gear G
Reference numeral 3 is rotated by an angle corresponding to the number of meshed teeth, like a satellite gear orbiting around the driven gear G2 on the apparatus body frame 2 side. As a result, the developing roll driving gear G5 of the developing device 2 which meshes with the driven gear G3 also rotates by a predetermined amount, and the developing roll 9 attached to the developing roll driving gear G5 moves by a predetermined amount before moving to the developing position. Will only rotate. The amount of rotation of the developing roll 9 is desirably, for example, about one rotation, but is set at least to such an extent that the previous development history can be eliminated.

As described above, in the above embodiment, the gear G3 for driving the developing roll 9 of the developing device 2 is engaged with the gear G2 on the apparatus main body immediately before the developing device 2 moves to the developing position. , The rotating body 7
In the rotary developing device 1 in which a plurality of developing devices 2 are mounted along the circumferential direction, it is possible to reliably prevent the occurrence of a development history with a simple configuration.

In the above embodiment, when the developing device moves to the developing position, the driven gear for rotating the developer carrier is engaged with the developing device as a fixed preliminary rotation gear. The above description has been made on the case where the driven gear for rotating the drive is used. However, the preliminary rotation gear is not limited to this, and is provided in a fixed state immediately before moving to the developing position as shown in FIG. As a matter of course, a circular gear 50 provided, or an internal gear 51 provided on an arc-shaped inner surface fixed and provided immediately before moving to the developing position as shown in FIG. 18 may be used.

[0065]

As described above, according to the present invention, when a developing device is not at a normal developing position in a rotary developing device having a plurality of developing devices mounted along the circumferential direction of a rotating body. By operating the developer stirring / conveying member of the developing device, the toner can be charged sufficiently and uniformly, a sufficient density can be maintained, and a fog phenomenon due to insufficient charging occurs. It is possible to provide a developing device capable of preventing the development.

Further, according to the present invention, it is possible to reliably prevent the development history from being generated with a simple configuration in a rotary type developing device having a plurality of developing units mounted along the circumferential direction of the rotating body. Can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram illustrating a rotary developing device as a developing device according to a first embodiment of the present invention.

FIG. 2 is a sectional configuration diagram showing a developing device of a rotary developing device as a developing device according to the first embodiment of the present invention.

FIG. 3 is a sectional configuration diagram showing a developing device of a rotary developing device as a developing device according to the first embodiment of the present invention.

FIG. 4 is a rear configuration diagram showing a rotary developing device as a developing device according to the first embodiment of the present invention.

FIG. 5 is a configuration diagram showing a drive system of the developing device according to the first embodiment of the present invention.

FIG. 6 is a timing chart showing the operation of the rotary developing device as the developing device according to the first embodiment of the present invention.

FIG. 7 is an illustration showing the operation of a rotary developing device as the developing device according to the first embodiment of the present invention.

FIG. 8 is a rear configuration diagram showing a rotary developing device as the developing device according to the first embodiment of the present invention.

FIG. 9 is a configuration diagram showing a drive system of the developing device according to the first embodiment of the present invention.

FIG. 10 is a graph showing experimental results.

FIG. 11 is a graph showing experimental results.

FIG. 12 is a configuration diagram showing a rotary developing device as a developing device according to a second embodiment of the present invention.

FIG. 13 is a rear configuration diagram showing a rotary developing device as a developing device according to a second embodiment of the present invention.

FIG. 14 is a configuration diagram showing a drive system of a developing device according to Embodiment 2 of the present invention.

FIG. 15 is a timing chart showing the operation of a rotary developing device as a developing device according to Embodiment 2 of the present invention.

FIG. 16 is an explanatory diagram showing an operation of a rotary developing device as a developing device according to a second embodiment of the present invention.

FIG. 17 is an explanatory diagram showing another example of the developing device according to the second embodiment of the present invention.

FIG. 18 is an explanatory diagram showing another example of the developing device according to the second embodiment of the present invention.

[Explanation of symbols]

1: rotary type developing device, 2Y, 2M, 2C, 2
K: developing unit, 7: rotating body, 9: developing roll, 10, 1
1: auger for agitating and transporting developer, 13: two-component developer, 2
0: apparatus body frame, 21: bracket, 22: clutch, 23: belt, G0: developing device drive gear, G1, G
2, G3: driven gear, G4: driven gear, G5: developing roll driving gear, G6: driven gear, G7: developer agitating and conveying auger driving gear, G8: driven agitating gear, G9: developer stirring and conveying auger driving gear , G10: second developing device drive gear,
G13: driven gear.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/08 507 G03G 15/08 507H (72) Inventor Ryuji Hattori 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox (72) Inventor Shigemi Murata 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Hirohisa Kono 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. Shino 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. F-term (reference) 2H030 AA05 AD02 AD17 BB24 BB33 BB71 2H071 BA03 BA14 BA32 CA01 CA02 CA05 CA09 DA08 DA15 DA26 DA31 EA18 2H077 AB02 AB14 AB15 AB18 AC02 AD02 AD06 DB14 DB18 DB21 EA01 GA13

Claims (4)

[Claims] 1. A developing position in which a plurality of developing devices accommodating a two-component developer are arranged along a circumferential direction of a rotating body, and the rotating body is rotated so that a desired developing device faces an image carrier. In a developing device for developing the electrostatic latent image formed on the image carrier by a desired developing device, each developing device transports the two-component developer while stirring the developer. A developing unit, wherein each of the developing units is configured to be able to drive the developer stirring and conveying unit at a position other than the developing position. 2. The developing device according to claim 1, wherein each of the developing devices does not drive the developer carrier at a position other than the developing position. 3. A position other than a developing position of each of said developing units,
The developing device according to claim 1, wherein the developing device is at a position rotated by about 180 degrees from the developing position. 4. A developing position in which a plurality of developing devices accommodating a two-component developer are arranged along a circumferential direction of a rotating body, and the rotating body is rotated so that a desired developing device faces an image carrier. And developing the electrostatic latent image formed on the image carrier with a two-component developer carried on a developer carrier of a desired developing device. A driven gear for rotationally driving the developer carrier, and a preliminary gear engaged with a driven gear for rotationally driving the developer carrier at a position immediately before the rotary body rotates and the developing device reaches the developing position. A rotating gear is provided, and when the developing device is moved to the developing position, a driven gear for rotationally driving the developer carrier is engaged with a fixed preliminary rotating gear so that the developer is rotated. The pre-rotation of the carrier by a predetermined amount is Developing device.