JPH0980888A - Development device - Google Patents

Abstract

(57) Abstract: In a developing device having a toner recycling mechanism, the number of revolutions of a toner agitator and the number of revolutions of a recycled toner conveying unit are respectively increased without increasing the size and cost of a drive source. To provide a developing device capable of controlling with an optimum value. A support case (2) having an opening formed toward a photosensitive member (1), and a developing sleeve as a developer carrying member having a part exposed from the opening and carrying a developer on the surface thereof. Four
And a toner agitator 32A rotatably supported in the support case, the cleaning device cleaning the residual toner on the photoconductor, and the cleaning device. And a recycle transport unit for recycling the toner into the developing device, a recycle toner transport member 40 made of a spiral wire is coaxially arranged on the toner agitator shaft 32 of the toner agitator. -The rotation of the conveying member and the rotation of the toner agitator shaft can be driven independently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device having a toner recycling mechanism, and more particularly, in a two-component developing device used in an image forming apparatus utilizing an electrophotographic process, a recycled toner conveying device and a toner agitator are provided. The present invention relates to a developing device that eliminates a problem that occurs when being driven by the same drive source.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a facsimile, a printer, etc., which utilizes an electrophotographic process, it is well known that optical image information such as reflected light of an original is uniformly charged in advance. An electrostatic latent image is formed by irradiating the body, and the toner image obtained by developing the electrostatic latent image with toner supplied from a developing device is transferred and fixed on a transfer paper to form an image. Is going. Further, the toner remaining on the surface of the photoconductor that has completed the transfer is removed by the cleaning device before moving to the next step. In the image forming unit provided with the toner recycling mechanism, the toner collected from the cleaning device is returned to the toner replenishing unit of the developing device through a predetermined collecting path so that the toner can be recycled. A conventional developing device having a toner recycling mechanism is composed of a developing tank portion, a toner hopper portion for accommodating a toner, and a recycling toner conveying member. The toner hopper portion supplies the toner into the developing tank. It consists of a toner replenishing roller and a toner agitator. In the developing device of this type, the recycling toner is fed from the cleaning device to the toner hopper portion by the recycling toner conveying member, so that the device becomes complicated and the cost is increased. In addition, it has a problem that it cannot be miniaturized.

[0003]

In a conventional developing device having a recycling mechanism, a toner agitator for stirring toner and carrier in the developing device and a toner agitator provided coaxially with the toner agitator shaft are provided. The recycle toner transporting member that feeds the recycle toner that has been transported from the cleaning device to the toner hopper section is driven by the same drive source and is configured to rotate the same. There is. However, since the toner agitator function and the recycling / conveying function are different from each other, if the toner agitator and the recycling toner conveying member are rotated in the same direction, either one or both functions may not be sufficiently exhibited. appear. That is, for example, when the number of revolutions of the recycled toner conveying member is set to a value most suitable for conveying the recycled toner, the number of revolutions of the toner agitator becomes too fast, resulting in excessive toner in the toner hopper. Is supplied to generate an abnormal image due to excess toner. Conversely, if the optimum rotation speed of the toner agitator is set in order to obtain the optimum supply amount to the toner hopper section, the toner carrying capacity of the recycled toner carrying section is deteriorated, and the toner is clogged in the cleaning device or the carrying path.
Solidification occurs. However, if the rotation speed is set to an intermediate value between the optimum rotation speeds of both, the supply capability of the toner to the toner hopper portion and the transport capability of the recycled toner are hindered. Further, if different drive sources are used to set the respective rotation speeds to the optimum values, the size of the apparatus and the cost are increased, which is a problem. The present invention controls the rotation speed of the toner agitator and the rotation speed of the recycled toner transport unit at the optimum values in the developing device having the toner recycling mechanism without increasing the size and cost by increasing the drive source. It is an object of the present invention to provide a developing device that makes it possible.

[0004]

In order to achieve the above-mentioned object, the invention of claim 1 is a support case having an opening formed toward the photosensitive member, and a part of the case is exposed from the opening. A developing device having a developing sleeve as a developer carrying member for carrying a developer on a surface thereof, and a toner agitator rotatably supported in a supporting case, the residual toner on a photosensitive member. A cleaning device for cleaning the toner and a toner recycling mechanism for recycling the toner cleaned by the cleaning device into the developing device, wherein the toner agitator shaft of the toner agitator is made of a spiral wire. The recycle toner transfer member is coaxially arranged, and the recycle toner transfer member and the toner agitator shaft can be independently driven to rotate. The invention of claim 2 is characterized in that only one end of the recycled toner conveying member provided coaxially with the toner-agitator shaft is in sliding contact with the toner-agitator shaft.

According to a third aspect of the present invention, the recycled toner carrying section for carrying the recycled toner from the cleaning device to the developing device has the other end rotatable around the cleaning device side end. With
From the recycled toner transport section to the recycled toner
It is configured to obtain a driving force to the conveying member, and the connection between the recycling toner conveying unit and the recycling toner conveying member is disconnected when the other end of the recycling toner conveying unit is rotated in the separating direction. To do. A fourth aspect of the present invention is characterized in that a part of the recycled toner transport unit and the recycled toner transport member are made of resin having an integral structure.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on an embodiment in which it is applied to a developing device used in an electrophotographic copying machine (hereinafter referred to as "copying machine") as an example of an image forming apparatus. FIG. 1 is a partial cross-sectional view showing a schematic configuration of the developing device according to this embodiment. This developing device is disposed laterally of a cylindrical photosensitive drum 1 which is a latent image carrier used in an image forming apparatus, and a support case 2 having an opening formed toward the photosensitive drum 1. , A part of which is exposed from the opening and toner and magnetic particles (hereinafter referred to as “carrier”).
A developing sleeve 4 as a developer carrying member for carrying the developer 3 on the surface thereof, and a magnet roller 5 comprising a fixed magnet group as a magnetic field generating means fixedly arranged inside the developing sleeve 4. , A doctor 6 as a developer regulating member for regulating the amount of the developer carried and conveyed on the developing sleeve 4, and a space for accommodating the developer staying above the developing sleeve 4 are formed. The doctor's front desk 7 and a toner hopper 8 as a toner accommodating portion are provided. Inside the developing sleeve 4 in FIG. 1, a magnet roller 5 is provided.
The polarity of the magnetic poles on the surface is illustrated.

[0007] Of the above-mentioned doctor's front desk 7, the developing sleeve
The end portion 7a of the sleeve 4 on the upstream side in the rotational direction extends along the developing sleeve 4 with a predetermined space between the developing sleeve 4 and the developing sleeve 4 and the outer surface of the developing sleeve 4. In the meantime, a developer accumulating portion A is formed in which the developer, which is not supplied to the developing position in the portion facing the photosensitive drum 1 and whose movement is blocked by the doctor 6, is accumulated. A developing sleeve facing the developer accumulating portion A.
A magnetic pole 5 a of a magnet roller 5 is arranged inside the bush 4. The toner hopper 8 is adjacent to the upstream side of the developer accumulating portion A in the developer conveying direction and is adjacent to the developing sleeve.
The toner replenishing opening 8 is provided to face the surface of the blade 4, and the toner 3a is sent to the space adjacent to the toner replenishing opening 8 while being stirred toward the toner replenishing opening 8a. A toner agitator 9 is provided.

Next, FIG. 2 shows a schematic view of an example of an image forming section having a toner recycling mechanism. The toner recycling mechanism 20 has a recycling toner transport unit (transport belt) 23 that connects the cleaning device 21 and the developing device 22. Protrusions 23a are provided on the outer peripheral surface of the conveyor belt 23 at predetermined intervals so that the recycled toner can be reliably held and conveyed. The conveyor belt 23 is stretched around shafts located at the axial center portions of gears 42a and 42b described later. The toner collected by the cleaning device 21 (hereinafter referred to as a recycled toner) is sent into the developing device 22 from a recycled toner carrying portion (carrying belt).

As shown in FIG. 3, the developing device 22 includes a side plate 3
0, 31 and the shaft 4a of the developing sleeve 4 between the side plates.
Is pivotally supported. One end of an agitator shaft 32 is rotatably supported by a side plate 31 at a position adjacent to the developing sleeve 4, and a gear 33 has its shaft center fixed to one end of the agitator shaft 32. The gear 33 meshes with a gear 34 fixed to one end of the shaft 4a of the developing sleeve. Therefore, the agitator shaft 32 is driven via the gear 34 of the developing sleeve. The other end of the agitator shaft 32 is loosely fitted in the support hole provided at the end of the drive gear 36 that is rotatably supported by the other side wall 35.
Is rotatably supported by the side plate 31 and the drive gear 36.

One end of a recycle toner conveying member (screw = spiral wire) 40 is fixed to the inner end surface of the gear 36 constituting the toner recycling mechanism 20, and the recycle toner conveying member 40 has an outer periphery of the agitator shaft 32. Is coaxially wound in a non-contact manner, and only the other end is in sliding contact with the agitator shaft 32. Therefore, the agitator shaft 3
2 and the recycle toner transfer member 40 are rotated relative to each other. The drive gear 36 meshes with a gear 42 b that is integrated with the shaft 41 of the recycled toner transport unit (transport belt) 23, and is driven by the force that drives the transport belt 23. If the drive gear 36 and the conveying screw 40 that form the toner recycling mechanism 20 are integrally made of resin, for example, a dedicated bearing for the toner-agitator shaft is not required, and the cost can be reduced.

As shown in FIG. 2, the conveyor belt 23 is wound around a shaft fixed to the gear 42a on the cleaning device 21 side and a shaft 41 fixed to the gear 42b on the developing device side, and at the same time, the toner recycling mechanism 20. Allows the other gear 42b to move up and down in the arrow direction around the gear 42a. Therefore, when it is necessary to remove the developing device from the main body of the device for maintenance or the like, the gear 42
By rotating b in the direction of separating from the drive gear 36 (separation direction), the developing device can be easily attached and detached. The conveyor belt 23 conveys the recycled toner toward the front side in the direction orthogonal to the paper surface of FIG. 3, and the conveyed toner is fed into the developing device through the opening 45, and the recycled toner is fed.
It is further fed in the direction of the arrow by the transport member (screw) 40, and is agitated and transported by the agitator 32A.
As described above, the recycle toner transfer member (screw) 40 is driven by the driving force for the toner recycle mechanism 20 via the drive gear 36, and the agitator shaft 32 is driven by the gear 3.
It is driven by the driving force for the developing roller via 4, 33.

The rotation speed of the drive motor in the recycling toner transportation must be set to such a speed that the toner is not accumulated in the recycling transportation portion (transport belt 23) and blocking is not caused. On the other hand, the toner agitator 32A in the developing tank has a role of supplying the toner to the developing roller, and when the rotation speed is too fast, the toner is excessively supplied, so that the toner agitator shaft 32 is supplied. And the recycle toner transfer member 40 can be independently driven.

[0013]

According to the developing device of claim 1, the toner is
Since the recycle toner transfer member (screw) 40 is provided coaxially with the agitator shaft 32 so that it can be independently driven to rotate, downsizing can be achieved, and the optimum rotation speed and recycling of the agitator can be achieved. Since the optimum number of rotations of the toner conveying member can be selected, there is an excellent effect that it is possible to provide a developing device having a highly reliable recycling mechanism without trouble. In the developing device of claim 2, toner-agitator
Recycle toner-conveying member 4 provided coaxially with the rotary shaft
Since only one end of 0 is in contact with the toner-agitator shaft,
Even if the number of rotations of the recycling conveying member increases, the contact area with the toner-agitator shaft is small, so that heat generation can be minimized. Therefore, there is an effect that the toner does not aggregate due to heat.

In the developing device of the third aspect, the recycled toner carrying part for carrying from the cleaning device to the developing device is rotatable around the end part on the cleaning device side, and the recycled toner carrying part is carried from this carrying part. Since it is configured to drive the members, while maintaining the miniaturization of recycling,
The developing device can be easily taken out from the main body. In the developing device according to the fourth aspect, since the drive gear of the toner recycling mechanism and the conveying screw are integrally made of resin, a dedicated bearing for the toner-agitator shaft is not required and the cost can be reduced. .

[Brief description of drawings]

FIG. 1 is a sectional view of a developing device to which the present invention is applied.

FIG. 2 is a schematic configuration explanatory view of the device of the present invention.

FIG. 3 is a sectional view of a main part of the device of the present invention.

[Explanation of symbols]

1 photoconductor drum, 2 support case, 3 developer, 4
Development sleeve, 5 magnet roller, 6 doctor, 7
Doctor's front desk, 8 toner hopper, 20 toner recycling mechanism, 21 cleaning device, 22 developing device, 23 recycled toner transport unit (transport belt), 3
0, 31, 35 Side plate, 32 Agitator shaft, 33, 3
4, 36 gears, 40 recycle toner conveying member (screw = spiral wire)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03G 21/10 G03G 21/00 326 (72) Inventor Yasushi Akiba 1-3, Nakamagome, Ota-ku, Tokyo No. 6 in Ricoh Co., Ltd.

Claims (4)

[Claims] 1. A support case having an opening formed toward the photosensitive member, and a developing sleeve as a developer carrying member, a part of which is exposed from the opening and carrying a developer on the surface. A developing device having a toner agitator rotatably supported in a support case, wherein the toner remaining on the photoconductor is
And a toner recycle mechanism having a recycle toner transport unit for recycling the toner cleaned by the cleaning device into the developing device, the toner agitator shaft of the toner agitator A recycle toner conveying member made of a spiral wire is coaxially arranged in the apparatus, and the recycle toner conveying member and the toner agitator shaft are configured to be independently rotatable and driven. apparatus. 2. The recycle toner conveying member provided coaxially with the toner agitator shaft has only one end slidably contacting the toner agitator shaft. The developing device described. 3. The recycled toner carrying portion has a structure in which the other end portion is rotatable around the cleaning device side end portion, and a driving force from the recycled toner carrying portion to the recycled toner carrying member. The connection between the recycled toner carrying section and the recycled toner carrying member is cut off when the other end of the recycled toner carrying section is rotated in the separating direction. Developing device. 4. The developing device according to claim 1, wherein a part of the toner recycling mechanism and the recycled toner conveying member are made of a resin having an integral structure.