JPH09146352A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the supply amount of developer to a developing sleeve uniform and to prevent the developer from falling from a developer tank. SOLUTION: This developing device 20 is provided with a 1st stirring member 3 constituted by fixing a spiral stirring blade 3b on a stirring shaft 3a, a 2nd stirring member 4 arranged in parallel with the member 3 by interposing a partitioning member 5 in between and having the same shape as the member 3, and a developer carrier 6 arranged proximately in parallel with the member 4. While the developer is circularly carried by the members 3 and 4, it is supplied to the carrier 6. In such a case, the diameter of the stirring shaft 3a of the member 3 is different from that of the stirring shaft 4a of the member 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in copying machines, printers, facsimiles, etc., and stirs and conveys a developer and toner, and puts the developer on the developer carrier to deposit a latent image on the image carrier. And a developing device for making the image visible.

[0002]

2. Description of the Related Art In a conventional developing apparatus, as shown in FIGS. 3 and 4, a developer tank 10 for holding a developer composed of toner and carrier has two developers with a partition member 5 interposed therebetween. Transport units 1 and 2 are formed. In the developer transport unit 1, a first stirring member 11 having a large number of transport blades 11b apparently fixed to a shaft 11a in a spiral shape is arranged in the developer transport unit 1. Similarly, the developer transport unit 2 includes the shaft 12a in the transport path 2a. A large number of conveying blades 12b apparently fixed in a spiral shape to the second
The stirring member 12 of is arranged. As shown in FIG.
Each of the transport blades 11b and 12b is partially cut out so that the developer can be stirred. The developer transport units 1 and 2 are formed parallel to the developer tank 10, and the shafts 11a and 12a are also arranged parallel to each other. Shaft 11a
One end of the developer tank 10 projects from the developer tank 10
Casing 3 of toner replenishing device (not shown)
0, and is rotatably supported by this casing 30. A spiral blade 11c for toner transportation is provided in a portion of the shaft 11a inside the casing 30, and toner supplied from the toner replenishing device connected to the casing 30 is supplied to the developer transportation unit 1.

[0003]

However, in the above-described conventional developing device, as shown in FIG. 3, the developer is conveyed from the developer conveying section 1 to the same conveying section 2 by the first stirring blade 11. In the developer transport unit 2, the amount of the developer is too small in the 2U unit and too much in the 2L unit because the developer is transported from the upstream 2U unit to the downstream 2L unit of the second stirring blade 12. As a result, there is a problem in that the developer is unevenly applied to the developing sleeve 6 and causes a defective image. Further, in the developer transport unit 2, there is a problem that the developer becomes excessive in the 2L portion and the developer drops from the developer tank 10. Therefore, the present invention has a simple structure in which the above-mentioned conventional problems are solved, the amount of the developer supplied to the developing sleeve is not biased, and the developer can be prevented from dropping from the developer tank. An object is to provide a developing device.

[0004]

The gist of the present invention resides in that, in claim 1, the first stirring member comprises a stirring shaft and spiral stirring blades fixed to the stirring shaft, and both end portions have communicating portions. A second stirring member having a shape similar to that of the first stirring member and a second stirring member arranged in parallel with the first stirring member with a partition member interposed therebetween, and arranged in parallel with the second stirring member in close proximity to the second stirring member. A developing agent carrier, the developer is circulated and conveyed by the first stirring member and the second stirring member while being supplied to the developer carrier. The stirring shaft diameter and the stirring shaft diameter of the second stirring member are different, and in claim 2, the stirring shaft diameter of the second stirring member is smaller than the stirring shaft diameter of the first stirring member. is there. In claim 3, the thickness of the stirring blade of the first stirring member is different from the thickness of the stirring blade of the second stirring member, and in claim 4, the thickness of the stirring blade of the second stirring member. Is smaller than the thickness of the stirring blade of the first stirring member.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, a developing device 20 includes a developer tank 10 for holding a developer composed of toner and carrier,
It is composed of two parallel developer carrying sections 1, a developer carrying section 2, and a developing sleeve 6 which is a developer carrying member and arranged in parallel therewith.

Developer transport unit 1 (hereinafter referred to as transport unit 1)
The first stirring member 3 apparently spirally fixed to the shaft 3a, which is a stirring shaft rotatably supported on the inner wall of the developer tank 10, is apparently arranged in a spiral shape. In the developer transport unit 2 (hereinafter referred to as the transport unit 2), a large number of transport blades 4b are apparently attached to a shaft 4a axially supported by the inner wall of the developer tank 10, and the second stirring member 4 is fixed in a spiral shape. Are arranged. As shown in FIG. 2, each of the transport blades 3b and 4b has a shape in which a portion is cut away so that the developer can be stirred, and a space is provided between the first stirring member 3 and the second stirring member 4. The partition member 5 is arranged. Further, a doctor blade 7 for controlling the amount of the developer is provided close to the developing sleeve 6.
Is arranged.

The shafts 3a and 4a are different from each other in axial diameter and the shaft 4a is thinner than the shaft 3a, and they are arranged in parallel with each other. Although the shafts 3a and 4a are all made of resin, they may be formed by passing a cored bar through the center. The transport blades 3b and 4b are
Although the cross-sectional shape is the same, as shown in FIG. 1, there is a difference in the thickness, and the conveying blade 4b is the conveying blade 3 more.
It is thinner than b. One end of the shaft 3a projects from the developer tank 10 and extends into a communication pipe 10a to a toner replenishing device (not shown) that communicates with the developer tank 10. The shaft 3a is rotatably supported by the communication pipe 10a. ing.
A spiral blade 3c for toner conveyance is provided in a portion of the shaft 3a inside the communication pipe 10a, and conveys the toner supplied from the toner replenishing device to the conveyance unit 1.

In this structure, the flow of the developer is conveyed in the direction of arrow A by the first stirring member 3 and in the direction of arrow B by the second stirring member 4, as in the conventional machine. The sizes of the transport sections 1 and 2 and the transport blades 3b and 4b of the developer tank 10 are the same as those of the conventional machine shown in FIG. 3, and the cross-sectional shape and pitch of the transport blades 3b and 4b are also those of the conventional machine. However, since the developer transport speed depends on these, the developer transport speed does not change between the first stirring member 3 and the second stirring member 4 as in the conventional machine.

However, the amount of the developer is the second stirring member 4 having the thin shaft 4b and the thin conveying blade 4b.
Since the carrying capacity of the second stirring member 4 is relatively increased, the carrying volume of the second stirring member 4 is larger. Therefore, as in the conventional machine, the downstream side 2U is more
The L portion has a larger amount of developer, but since the carrying portion 2 has a larger volume than the carrying portion 1, the second agitating member 4 becomes less so that the developer does not get on the developing sleeve 6. There is no difference in the amount of developer in the longitudinal direction of
It is possible to avoid an excessive amount of the developer in the 2L part.

In this embodiment, the thickness of the transport blade 3b is thicker than that of the transport blade 4b and the thickness of the shaft 3a is thicker than that of the shaft 4a. However, by changing the pitch of the transport blades 3b and 4b. Since the developer carrying speed can be changed, the reverse of this embodiment, the carrying blade 4b.
Can be thicker than the conveying blade 3b and the shaft 4a can be thicker than the shaft 3a.

[0011]

As described above, according to the first and second aspects, the stirring shaft diameter of the first stirring member and the stirring shaft diameter of the second stirring member are different, and the stirring shaft of the second stirring member is different. Since the diameter is smaller than the diameter of the stirring shaft of the first stirring member, the amount of the developer stirred and conveyed by the second stirring member is larger than that of the first stirring member, and the amount of the developer is larger than that of the upstream side of the second stirring member. Due to the buffer effect of softening the difference in the amount of developer from the downstream side, the circulation of the developer is balanced, and it is possible to avoid the problem that the developer does not get on the developer carrier due to insufficient developer as in the past. In addition, it is possible to prevent an abnormal image caused by the bias of the developer and the developer from dropping from the developer tank. According to claims 3 and 4, the plate thickness of the stirring blade of the first stirring member is different from the plate thickness of the stirring blade of the second stirring member, and the plate thickness of the stirring blade of the second stirring member is Since it is thinner than the plate thickness of the stirring blade of the first stirring member, the same effects as those of claims 1 and 2 can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic plan sectional view of a developing device showing an embodiment of the present invention.

FIG. 2 is a schematic view showing a Y-Y section of the developing device of FIG.

FIG. 3 is a schematic plan sectional view showing a conventional developing device.

FIG. 4 is a schematic view showing an X-X cross section of the developing device of FIG.

[Explanation of symbols]

 3 1st stirring member 3a, 4a Stirring shaft 3b, 4b Stirring blade 4 2nd stirring member 5 Partition member 6 Developer image carrier 20 Developing device

Claims (4)

[Claims] 1. A first stirring member formed by fixing a spiral stirring blade to a stirring shaft and a partition member having a communicating portion at both ends thereof are arranged in parallel with the first stirring member. , A second stirring member having a shape similar to that of the first stirring member, and a developer carrying member arranged in parallel with the second stirring member in proximity to the second stirring member. In the developing device that supplies the developer to the developer carrier while circulating and conveying the second stirring member, the stirring shaft diameter of the first stirring member and the stirring shaft diameter of the second stirring member are different from each other. Characteristic developing device. 2. The developing device according to claim 1, wherein the stirring shaft diameter of the second stirring member is smaller than the stirring shaft diameter of the first stirring member. 3. The developing device according to claim 1, wherein the thickness of the stirring blade of the first stirring member is different from the thickness of the stirring blade of the second stirring member. 4. The thickness of the stirring blade of the second stirring member is
The developing device according to claim 3, wherein the stirring blade of the first stirring member is thinner than the thickness of the stirring blade.