JPH11109739A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of coping with high speed operation without raising cost and complicating device constitution by coupling a movable developing unit and a movable replenishing unit which can move with the developing unit in a state where they have a given degree of freedom in a moving direction each other. SOLUTION: The developing unit 4a and a toner storing unit 4b functioning as the replenishing unit are coupled in a state where they have the specified degree of freedom in a turning direction each other. Thus, the behavior of the unit 4a is different from that of the unit 4b when the developing device is rotated, so that load imposed on a revolver motor 101 is lightened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an image forming apparatus such as a copying machine, a facsimile, and a printer.

[0002]

2. Description of the Related Art Conventionally, a color separation light image is exposed to a latent image carrier, and each formed latent image is developed with a toner of a complementary color of the color separation light. 2. Description of the Related Art A developing device including a plurality of developing devices used in a full-color image forming apparatus of a type in which image data is transferred by being superimposed on an image is known. As such a developing device, from the viewpoint of space saving and effective use of space, a developing unit having a plurality of developing devices disposed around the rotation center line is rotated around the rotation center line to perform arbitrary development. It is advantageous to use a rotary developing device in which the developing device is sequentially moved to a developing position opposed to the latent image carrier to develop the latent image on the latent image carrier with each color toner.

Further, a toner replenishing section for storing replenishing toner and replenishing the toner to each developing device is constituted by the developing devices in view of simplicity of the mechanism and effective use of space. It is advantageous to use a toner container unit having a plurality of detachable toner containers that are detachable from each of the developing units of the developing unit and that are configured to be rotatable together with the developing unit.

[0004]

In the rotary type developing apparatus employing the toner container unit having the above-mentioned structure, it is necessary to mount a considerable amount of both developer and toner in order to cope with high-speed image formation. Therefore, it is necessary to rotate an object having a large weight and a large size and a large moment of inertia at a high speed. Generally, a stepping motor is used as the revolver drive motor because rotation stop position accuracy is required. However, those that support high load and high speed rotation as described above are not versatile and are very expensive, or require the use of an AC power supply as an input power supply, which complicates the configuration. For this reason,
It is sometimes difficult to mount it on office equipment such as a copying machine or a printer, and there is a problem that it is difficult to increase the speed due to such restrictions on the motor side.

[0005] The above problem is caused by a rotary developing device in which an arbitrary developing unit is sequentially moved to a developing position facing a latent image carrier by rotation to develop a latent image on the latent image carrier with toner of each color. In addition to the above, a plurality of developing units that move to a predetermined developing position to perform a developing operation are provided. The developing unit is configured to be movable. A plurality of toner replenishing devices for replenishing the toner, and a replenishing unit configured to be movable together with the developing device unit. By moving the developing device unit, a desired developing device is moved to the predetermined developing position. This can occur in a developing device that performs a developing operation by displacing the developing device.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a developing apparatus capable of coping with high speed without increasing the cost or complicating the apparatus configuration. is there.

[0007]

According to a first aspect of the present invention, there is provided a developing unit having a plurality of developing units, the developing unit being configured to be movable and a plurality of developing units being provided. A plurality of toner replenishing devices provided to supply toner to each of the developing units, and a replenishing unit configured to be movable together with the developing unit. A developing device that performs a developing operation by displacing the developing device to a predetermined developing position, wherein the developing device unit and the replenishing unit are connected with a predetermined degree of freedom in the moving direction. It is assumed that.

In this developing device, since the developing unit and the replenishing unit have a predetermined degree of freedom with respect to the moving direction of the developing unit, one of the developing unit and the replenishing unit is provided. Is moved, the other acts as a load later than the one acts as a load, and the load is dispersed. Thereby, compared to the case where the developing unit and the replenishing unit simultaneously act as loads at the start of the movement,
The load decreases.

According to a second aspect of the present invention, in the developing device according to the first aspect, the developing unit and the replenishing unit are connected to each other.
It is characterized by being connected via an elastic body having elasticity in the moving direction.

In this developing device, since the developing unit and the replenishing unit are connected via an elastic body having elasticity in the moving direction, the degree of freedom in the moving direction is increased. State. Thus, when one of the developing unit and the replenishing unit is moved, the other acts as a load later than the one acts as a load, and the load is dispersed. Therefore, the load is reduced as compared with the case where the developing unit and the replenishing unit simultaneously act as loads at the start of the movement.

[0011]

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

The revolver developing device 4 includes a plurality of developing devices rotatable around a central axis, in the illustrated example, four developing devices.
A developing unit for performing a developing operation by moving a desired developing device to a predetermined developing position facing the photosensitive drum 1 by rotation about the central axis, and a plurality of toners corresponding to the developing devices; It has a container and has a toner container unit that rotates similarly to the developing unit. Specifically, for example, developing units 41Bk and 41 for four colors of black, cyan, magenta, and yellow, respectively, are internally provided.
C, 41M, and 41Y are formed, and the developing device unit has a substantially cylindrical outer periphery which is rotatably mounted around the central axis line in the printer body. Black, cyan, and magenta correspond to each developing device in a one-to-one correspondence. Holding four toner cartridges (not shown) as a toner container containing yellow toner, and being mounted so as to be substantially coaxial with the developing device unit in front of the developing device unit in the direction of the center axis thereof, and being mounted around the center axis. The image forming apparatus includes a toner container unit (not shown) that rotates together with the developing unit.
The revolver developing device 4 is driven to rotate in a direction indicated by an arrow C by a revolver motor (not shown), which will be described later, and performs a developing operation by positioning any one of the developing devices used for development at a developing position.

Each color image formed on the photosensitive drum 1 is placed on an intermediate transfer belt 5 rotating in the direction of arrow B in FIG. 1 in synchronization with the photosensitive drum 1 for each of yellow, magenta, cyan and black. Are sequentially superimposed and transferred by the primary transfer charger 6. The yellow, magenta, cyan, and black images superimposed on the intermediate transfer belt 5 are fed from a not-shown double-sided copying / automatic paper feed cassette or a not-shown manual paper feed tray to a not-shown paper feed roller and registration rollers 9. Are collectively transferred by the secondary transfer charger 11 onto the transfer paper conveyed to the transfer section via After completion of the transfer, the transfer paper is fixed with a toner image by a fixing device (not shown) and is discharged out of the apparatus as a full-color print.

The toner on the photosensitive drum 1 that has not been transferred onto the intermediate transfer belt 5 is removed by the photosensitive cleaner 13.
Is removed from the photosensitive drum 1 by the
The toner on the intermediate transfer belt 5 that has not been transferred onto
It is removed from the intermediate transfer belt 5 by the intermediate transfer belt cleaner 14.

FIG. 5A is a sectional view showing the internal structure of the developing unit 4a of the revolver developing device 4, and FIG.
FIG. 4 is a cross-sectional view illustrating an internal structure of a toner container unit 4b of the revolver developing device. In FIG. 5A, as described above, four developing units 41Bk, 41C, 41M, and 41 having substantially the same shape in the circumferential direction are provided in the developing unit 4a.
Y is formed. In each developing unit, a two-component developer (hereinafter, referred to as a carrier) as a developer and a toner of each color is used.
Developer). In the illustrated example, the black developing device 41Bk containing the black toner and the carrier is located at the developing position facing the photoconductor drum 1, and the yellow developing device 41Y containing the yellow toner and the carrier in the counterclockwise order in the drawing. A magenta developing device 41M containing magenta toner and carrier, and a cyan developing device 41C containing cyan toner and carrier are provided.

Here, the four developing units 41Bk, 41Y,
Since the internal structures of 41M and 41C are exactly the same,
Hereinafter, the internal structure will be described taking the black developing device 41Bk at the developing position as an example, and the description of the internal structure of the other developing devices will be omitted. The developing device is provided with a developing roller 42Bk as a developer carrier, and is disposed in parallel with the developing roller 42Bk. The developer is stirred while the developer in the developing device is stirred.
It has first and second stirring screws 43Bk and 44Bk that convey in opposite directions in the axial direction. Among the two stirring screws, the first stirring screw 43Bk is disposed at a position closer to the developing roller 42Bk. The developing roller 42Bk includes a fixed magnet roller and a rotatable sleeve provided on the outer periphery thereof.

By rotating the developing unit 4a of the revolver developing device 4 having the above-described configuration in steps of 90 ° in the direction of arrow C, each developing unit is sequentially moved to the developing position facing the photosensitive drum 1, and The electrostatic latent image on the photosensitive drum 1 is visualized.

Although not shown, on the rear side of the rear plate of the revolver, which is the rear plate of the developing unit 4a, a developing input gear of the developing unit 4a which meshes with a developing drive gear (not shown) of the main body is turned. It is provided movably. Further, an idle gear for transmitting the rotation of the development input gear is provided on a gear fixed to the shaft end of the developing roller or the first and second stirring screws. On the rear plate of the main body, a revolver driving gear driven by a revolver motor described later for rotating and driving the developing unit 4a is provided at a position where the revolver gear is fixed to the revolver rear plate. Further, the developing drive gear driven by a developing drive motor for driving a developing roller and the like in the developing unit 32 is provided with the developing input gear for a developing device located at a developing position facing the photosensitive drum 1. It is installed at the position where it meshes with the gear.

The toner container unit 4b as a replenishing unit is constituted by four toner replenishing units as toner replenishing devices for replenishing toner to the four developing units, respectively. The toner supply unit includes a toner cartridge and a toner hopper. In FIG. 5B, a total of four toner hoppers 45 are provided in the toner container unit 4b so as to correspond to the respective developing units on a one-to-one basis.
Bk, 45Y, 45M, and 45C are attached.
The toner hoppers 45Bk, 45Y, 45M, 45C
This is for receiving toner from each toner cartridge. Toner supply pipes 46Bk, 46Y, 46M, 46C as toner supply paths for supplying toner are provided from the respective toner hoppers toward the developing devices. The toner supply pipes 46Bk, 46Y, 46
Inside each of M and 46C, there are provided toner conveying screws 47Bk, 47Y, 47M and 47C for conveying the toner in the toner hopper toward the respective developing devices, and extend into the toner hopper. . These toner conveying screws 47Bk, 47Y, 47M, 47C
Are set such that when the corresponding developing device is located at the developing position, the toner transport screw 47 is located almost directly above the extending portion of the second stirring screw 44 in the corresponding developing device. . The state shown in FIG.
FIG. 3A is a cross-sectional view of the toner container unit when the black developing device is located at the developing position as set in FIG.

The above four toner hoppers 45Bk, 45
Y, 45M, and 45C all have the same shape. That is, a peripheral wall portion surrounding the toner transport screw 47 and having a toner receiving port formed at a position above the toner transport screw 47 when the corresponding developing device is located at the developing position. Around the toner cartridge 48 of the same shape for each color containing toner.
Bk, 48Y, 48M, and 48C are formed with a toner cartridge mounting portion that is mounted so that the toner discharge ports thereof face downward and coincide with the toner receiving ports.

Although not shown, the shaft of the toner conveying screw 47 protrudes toward the developing unit 32, and a gear (not shown) is fixed to an end of the shaft. A supply input gear for driving input is provided so as to mesh with the gear. Of the supply input gears provided for each toner transport screw 47, the toner transport screw 47 corresponding to the developing device at the developing position
Is engaged with a gear driven by a supply motor mounted on the rear plate of the main body. This allows
The toner conveying screw 47 can be driven to rotate by a supply motor.

FIG. 1 shows a revolver developing device 4 of the printer.
It is a longitudinal cross-sectional view of the vicinity. The left side in the figure shows the apparatus rear side, and the right side in the figure shows the apparatus front side. For simplicity, only the toner cartridge 48 and the toner hopper 45 for one color are shown in the toner container unit 4b. The developing unit 4a is held between the front plate 50 of the revolver and the rear plate 51 of the revolver. On the front side of the revolver front side plate 50, a ring 52 having a protruding portion 52a protruding toward the toner container unit 4b at the center is provided.
It is provided coaxially with the developing unit 4a, is positioned on the main body front side plate 54 via a bearing 53, and is rotatably supported. Further, a revolver gear 55 is fixed to the rear side of the revolver rear side plate 51 in the apparatus. The central portion of the revolver gear 55 projects axially to the rear side of the device, and the projecting portion 55a is connected to the main body rear plate 5 via a bearing 56.
7 is positioned. With the above configuration, the developing device unit 4a is rotatably held with respect to the main body device.

The toner container unit 4b is mounted closer to the apparatus than the developing unit 4a, and a toner hopper holding plate 49 integrally supports a toner cartridge 48 and a toner hopper 45 for four colors.

From the toner hopper 45, the above-described toner supply pipe 46 is provided toward the developing device.
The toner in the toner cartridge 48 and the toner hopper 45 is transported toward the developing device by the toner transport screw 47 therein. At one end of the toner supply pipe 46 on the developing device side, a pipe opening 46a for discharging toner in the pipe 46 is provided, and at a portion corresponding to the pipe opening 46a of the developing device, Developing device opening 4 for receiving toner from toner supply pipe 46
1a is provided. With such a configuration, the toner supply pipe 46 and the developing device 41 communicate with each other. Then, the toner conveyed from the toner hopper 45 by the toner conveying screw 47 through the pipe opening 46a and the developing device opening 41a is used for the developing device 41.
Will be replenished inside. The toner supply pipe 46
A seal 60 made of an elastic member such as polyurethane foam is provided around the communicating portion between the developing device 41 and the toner to prevent toner scattering.

In the present embodiment, the developing unit 4a and the toner container unit 4b are
A configuration is adopted in which the components are connected in a state of having a predetermined degree of freedom in the moving direction. Hereinafter, this configuration and operation will be described in detail. In the illustrated apparatus, the toner hopper holding plate 49 is provided at the center of rotation with the developing unit 4a.
Is slidably fitted to the projection 52a of the ring 52.
As shown in FIG. 2, the toner hopper holding plate 49 has three long holes 49a along the rotation direction, and each of the long holes 49a slides in the rotation direction with a stepped screw 70. It is attached to the ring 52 as possible. In addition, one of the stepped screws 70 in the figure omits the stepped portion of the stepped screw 70 and shows only the shaft portion. With such a configuration, the toner container unit 4b is connected to the developing unit 4a with a predetermined degree of freedom in the rotation direction.

The developing unit 4a includes the revolver motor 1
01 is driven via the revolver gear 101a. When the developing unit 4a is driven to rotate, the toner container unit 4b also rotates in conjunction with the developing unit 4a. At this time, since the toner container unit 4b is connected to the developing unit 4a with a predetermined degree of freedom, it behaves differently from the developing unit 4a. As a result, the load torque applied to the revolver motor 101 is different from the case where the toner container unit 4b is almost completely fixed without any degree of freedom in the rotation direction. This difference will be described with reference to FIG. FIG. 3 shows the developing unit 4
The rotation speed of the revolver motor when a rotates by 90 °, that is, the number of rotations, and the load torque applied to the revolver motor,
FIG. 4 is an explanatory diagram shown along a time axis. FIG. 3A shows the rotational speed and the load torque of the developing device according to the present embodiment, whereas FIG. 3B shows a developing unit 4a and a toner container unit 4b as comparative examples. The above shows the rotational speed and the load torque of a developing device in which the rotational speed and the rotational direction of the developing device are almost completely fixed without any degree of freedom. First, at the start of rotation, the load torque is the largest in both FIGS. 3 (a) and 3 (b). Here, in the case of the developing device according to the comparative example, since the developing device unit 4a and the toner container unit 4b are fixed and integrated, the entire load is applied to the motor at a stretch. In the case of the developing device, the load of the toner container unit 4b acts with a delay with respect to the load of the developing unit 4a because of the degree of freedom, and the load is dispersed. As a result, as can be seen from FIGS. 3A and 3B, the load torque of the developing device according to the present embodiment is more
The load torque is smaller than the load torque of the developing device according to the comparative example. Thereafter, both FIGS. 3A and 3B show that the load torque fluctuates with a certain amplitude. This fluctuation is a type of vibration caused by driving, which appears in the load torque, and is caused by the moment of inertia of the load, friction torque, driving pattern (maximum speed, acceleration / deceleration, time, etc.). In the developing device according to the present embodiment, the toner container unit 4
By giving b a degree of freedom, the behaviors of the two are different. Then, the amplitude of the vibration is reduced by a kind of damper effect as compared with the developing device according to the comparative example,
That is, the load torque and the fluctuation range thereof are smaller than those of the developing device according to the comparative example. From the above, since the load on the revolver motor 101 can be reduced, it is possible to cope with a high speed without increasing the cost and complicating the device configuration. (Hereinafter, margin)

By changing the degree of freedom, the load torque characteristic also changes. In the illustrated device, the characteristics of the load torque change by changing the length of the long hole 49a of the toner hopper holding plate 49. This degree of freedom is desirably set according to characteristics of the load itself, such as the moment of inertia and friction torque, which are related to the load torque.

FIG. 6 is an explanatory view showing another example of the developing device according to the present embodiment. The apparatus shown in FIG. 6 employs a configuration in which the developing unit 4a and the toner container unit 4b are connected via an elastic body having elasticity in the rotation direction. Specifically, the developing unit 4a is provided on the front side of the revolver front side plate 50 with a coaxial shape with the developing unit 4a, and a ring 52 positioned on the main body front side plate 54 via a bearing 53 is provided. The toner hopper holding plate 49 of the toner container unit 4b is fixed to the other end of the joint 71 by welding. Thus, the developing unit 4a and the toner container unit 4b are connected with a degree of freedom. Therefore, as in the case of the developing device of FIG. 1, the behavior of the developing device unit 4a and the behavior of the toner container unit 4b are different when the developing device rotates, and the revolver motor 10
1 can be reduced. Therefore, it is possible to cope with a high speed without increasing the cost or complicating the device configuration.

In the example shown in FIG.
The characteristics of the load torque can be changed by changing the rubber hardness and thickness of the rubber. Further, as a material of the joint 71, a spring material, a resin, or the like may be used in addition to the rubber material.

In the above embodiment, an example in which the present invention is applied to a developing device using a two-component developer has been described. However, the present invention may be applied to a developing device using a one-component developer. .

[0031]

According to the first and second aspects of the present invention, there is an excellent effect that it is possible to respond to a high speed without increasing the cost and complicating the configuration of the apparatus.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a revolver developing device according to an embodiment.

FIG. 2 is an explanatory diagram of a toner hopper holding plate of the revolver developing device.

FIGS. 3A and 3B show a case where the developing unit 4a is 9
The figure which showed the rotation speed of the revolver motor at the time of 0 degree rotation, and the load torque applied to the revolver motor along a time axis.

FIG. 4 is a schematic configuration diagram of a main part of an electrophotographic printer including the revolver developing device.

FIG. 5A is a cross-sectional view illustrating an internal structure of a developing unit of the revolver developing device. FIG. 2B is a cross-sectional view illustrating an internal structure of a toner container unit of the revolver developing device.

FIG. 6 is an explanatory diagram of a revolver developing device according to a modification.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2 Charger 3 Laser beam 4 Revolver developing device 4a Developing unit 4b Toner container unit 5 Intermediate transfer belt 6 Primary transfer charger 9 Registration roller 11 Secondary transfer charger 13 Photoconductor cleaner 14 Intermediate transfer belt cleaner 49 Toner hopper holding plate 49a Long hole 55 Revolver gear 70 Stepped screw 71 Joint 101 Revolver motor 101a Revolver drive gear

Claims (2)

[Claims] A developing device unit having a plurality of developing devices and configured to be movable; and a plurality of toner replenishing devices provided for the respective developing devices and supplying toner to the respective developing devices. And a replenishing unit configured to be movable together with the developing device unit, wherein the developing device performs a developing operation by displacing a desired developing device to a predetermined developing position by moving the developing device unit. A developing device wherein the developing unit and the replenishing unit are connected with a predetermined degree of freedom in the moving direction. 2. The developing device according to claim 1, wherein said developing unit and said replenishing unit are connected via an elastic body having elasticity in said moving direction.