JPH056192B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a developing device used in a dry electrophotographic apparatus.

(Prior art) A developing device using radial conveying blades a as shown in FIG. 1 as a developing device using a two-component developer has the advantage of simplifying the device and reducing costs. Since the stirring action is mainly limited to the circumferential direction, there are problems such as poor ability to charge the supplied toner and background smearing.Additionally, separate cross mixing is required to stir the developer in the lateral direction. Since mechanism b is required, there is a problem in that the device becomes larger.

On the other hand, the device disclosed in Japanese Patent Application Laid-Open No. 54-119934 is for agitating the replenished toner while transferring it from one side to the other using an axial transfer mechanism provided in a conveying impeller. However, in this device, since the developer stored in the storage layer cannot be transported in the axial direction, there is a problem in that the image density may vary in some areas.

(Purpose) The present invention has been made in view of the above problems, and its purpose is to provide a developing device with a simple structure that has not only a circumferential stirring function but also an axial circulation and stirring function. It is about providing.

(Means for Achieving the Object) That is, the present invention provides a dry developing device for achieving the above object, in which a developer is applied to a developing roller on the periphery of a hollow rotating shaft that is disposed in parallel and close to a developing roller. A radial blade is formed to supply the developer to the roller, and a transport blade is provided on the outer periphery of the blade to transport the developer in the axial direction. The inlet and outlet openings for the developer are provided at intervals, and a rotary transfer member for transferring the developer in a direction opposite to the transfer direction of the transfer member is disposed within the rotating shaft.

(Example) The details of the present invention will be described below based on illustrated examples.

2 and 3 show an embodiment of the present invention, in which reference numeral 1 denotes an agitation impeller disposed in parallel and close to the developing roller 10, around a sleeve-shaped shaft 2. is integrally formed with radial impellers 5 that agitate and supply the developer in the storage tank 12 to the developing roller 10, and on the outer periphery of the impeller 1 are spiral blades extending from one end to the other. It is surrounded by a developer axially transporting blade 6 having a shape. 7 is
The conveyance screw transports the developer in the direction opposite to the conveyance blades 6 within the sleeve shaft 2 of the conveyance impeller 1 described above. A blade 9 is provided and is configured to send out the developer flowing in from the inlet 3 provided at one end of the sleeve shaft 2 and the toner replenished here toward the outlet 4 at the other end.

In the figure, reference numeral 11 indicates a doctor blade for aligning the ears of the magnetic brush formed on the developing roller 10 to a certain height, 13 indicates a toner tank, 14 indicates a toner replenishment roller, and 15 indicates an inlet for recycled toner. It shows.

In the embodiment described above, when the transport impeller 1 rotates in the direction of the arrow in the figure, the blades 5 draw up the developer in the storage tank 12 and supply it to the developing roller 10 while stirring it in the circumferential direction. On the other hand, with this rotation, the spiral transfer blade 6 surrounding the outer periphery of the impeller 1 transfers the developer in the developer tank 12 from right to left in the figure.
At the end of the sleeve shaft 2, the developer is guided into the shaft 2 from the inlet 3 in cooperation with the conveying blades 5.

In this embodiment, a toner tank 13 is provided above the inlet 3, and toner is supplied to the inlet 3 from a toner supply roller 14 provided at the opening end of the toner tank 13 in accordance with an output signal from a toner concentration sensor. Because of this structure, the conveying screw 7 rotating within the sleeve shaft 2 stirs and mixes the developer that has flowed into the inflow port 3 and the replenished toner while moving the developer in the opposite direction to the conveying direction by the conveying blades 6. In other words, the developer is conveyed toward the outlet 4 that is open at the right end in the figure, and thereafter the developer is circulated in the axial direction one by one from left to right and from right to left by the conveying blades 6 and the conveying screw 7. while supplying it to the developing roller 10.

Although the above description is for a type of device in which toner is replenished to one end of the storage tank 12, similar agitation and mixing can be performed in a device in which toner is replenished over almost the entire width of the storage tank 12. can be set.

(Effects) As explained above, according to the present invention, since the blades for transporting the developer in the axial direction are provided on the outer periphery of the impeller for supplying the developer, the blades for transporting the developer in the radial direction are provided in the outer periphery near the developing roller. By mixing the developer in the axial direction, it is possible to efficiently stir and supply the charged developer to the developing roller.

Moreover, since the developer inflow and outflow openings are provided at intervals on the circumference of the rotating shaft where the radial blades are provided, the developer is moved between the radial blades by the transfer blades in the axial direction. While transporting the developer, it is possible to efficiently feed the developer one after another into the inflow opening without being affected by the rotation of the rotating shaft. The rotating body itself does not cause problems such as creating a pool of developer near the inlet opening, which obstructs the rotation of the rotating body, or fatigues the developer. As a result, the developer can be smoothly circulated in the axial direction and efficiently stirred and mixed. What is more noteworthy is that the stirring, mixing, and circulation can be performed only by the impeller, so that the developing device can be significantly downsized.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of a conventional device;
FIG. 2 is a configuration diagram of an apparatus showing an embodiment of the present invention, and FIG. 3 is a side view of a conveying impeller. 1... Conveyance impeller, 2... Sleeve shaft, 3...
Inflow port, 4... Outlet port, 5... Conveyance blade, 6...
Transfer blade, 7...Transfer screw, 10...Developing roller.

Claims (1)

[Claims] 1. Radial blades are formed on the periphery of a hollow rotating shaft that is disposed close to and parallel to the developing roller to supply the developer to the developing roller, and the developer is further transferred in the axial direction on the outer periphery of the blade. In addition to providing a transfer blade, an inflow opening and an outflow opening for the developer are provided at intervals in the transfer direction of the transfer blade and on the circumference of the rotating shaft on which the radial blades are formed, and A dry type developing device further comprising a rotary transfer member for transferring developer in a direction opposite to the transfer direction of the transfer member.