JPH0247747B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device such as an electrophotographic copying machine, and more particularly to a two-component developing device that is provided with a developer stirring means in a developer reservoir to mainly supply toner to the developer reservoir. The present invention relates to an improvement in a developing device using a developing agent.

In the conventional developing device as described above, the replenished toner is supplied to the magnetic brush developing means without being sufficiently mixed with the developer in the developer reservoir, and as a result, development is not performed clearly and fogging may occur. This may cause dirt inside the machine.

The present invention has been made in order to provide a developing device that prevents the above-mentioned problems from occurring, and includes a developer stirring means having a cylindrical member in a developer reservoir, and a developer stirring means having a cylindrical member inside the cylindrical member. In a developing device using a two-component developer configured to replenish toner,
A developer reflux path is formed between the inside and outside of the cylindrical member, and the cylindrical member is arranged coaxially with the cylindrical member and outside the cylindrical member. The developer on the outside of the cylindrical member is conveyed in the opposite direction to the direction in which the developer on the outer periphery of the cylindrical member is conveyed near the entrance of the cylindrical member into which the developer is fed inside. The developing device is characterized in that it is provided with an auxiliary means for feeding it inside.

That is, in the developing device of the present invention, a developer reflux path is formed between the inside and outside of the cylindrical member, and toner is replenished into the inside of the cylindrical member, so that the supplied toner is This prevents the developer from being supplied to the magnetic brush developing means without being mixed with the developer in the developer reservoir, thereby preventing unclear development, fogging, and dirt inside the machine. There is.

Hereinafter, the present invention will be explained based on the drawings.

Fig. 1 is a schematic sectional view in the direction perpendicular to the axis showing an example of the developing device of the present invention, Fig. 2 is a partial sectional view in the direction parallel to the axis, and Figs. FIG. 3 is a partial side view showing an example of a rotating member.

In FIGS. 1 and 2, 1 is the casing of the developing device, and 2 is a magnet body 3 that rotates in the direction of the arrow inside.
4 is a developer removing member that removes developer from the surface of the magnetic brush sleeve 2, and 5 is a developer removing member that is attached to the surface of the magnetic brush sleeve 2 and rotates in the direction of the arrow. A developer regulating member 6 that regulates the amount of developer to be conveyed has spiral reflux promoting blades 6a on its outer periphery and developer reflux assisting means 6b on its shaft, and rotates in the direction of the arrow. A cylindrical member provided in the developer reservoir 1a at the lower part of the casing 1, 7 a screw-propelling rotating member fitted inside the cylindrical member 6 and provided to rotate in the direction of the arrow, 8 a screw-propelling member Hollow portion 7a of shaft of rotary member 7
This is a screw conveyor fitted with a screw conveyor.

In the developing device of the present invention as described above, the developer in the developer reservoir 1a is moved inside the cylindrical member 6 by rotating the cylindrical member 6 and the screw-propelled rotating member 7 in the directions of the arrows. The water flows from left to right in Figure 2, and then flows back to the outside from right to left. Then, the developer flowing on the outside adheres to the surface of the magnetic brush sleeve 2 between the developer removing member 4 and the developer regulating member 5, passes through the developer regulating member 5, and reaches the surface of the image carrier Z. By rubbing, the electrostatic image on the Z surface of the image carrier is developed. On the other hand, the toner to be replenished is carried from left to right inside the hollow part 7a of the shaft of the screw propelling rotating member 7 by the rotation of the screw conveyor 8 in the direction of the arrow, and is provided at the dead end part of the hollow part 7a. It is fed into the inside of the cylindrical member 6 through the opening 7b. Therefore, the replenishment toner is supplied to the cylindrical member 6.
It merges with the developer flowing inside the cylindrical member 6 and is sent by the screw propulsion type rotating member 7, and when it leaves the inner right end of the cylindrical member 6, it is sufficiently mixed with the developer. It is no longer supplied to the brush sleeve 2. In addition, the cylindrical member 6 of FIG. 2 of the screw propulsion type rotating member 7
The propelling blade portion 7c protruding outward from the left end serves as an auxiliary means for refluxing the developer in the developer reservoir 1a to the inside of the cylindrical member 6. Together with the auxiliary means 6b, reflux is ensured smoothly. In addition, in the cross-sectional view of FIG. 1, the support member that supports and fixes the cylindrical member 6 to the shaft part so that the cylindrical member 6 rotates with the rotation of the shaft part is shown. It is omitted because it is sufficient that the member 6 is supported by its shaft. The cross-sectional view of FIG. 2 shows a cross-sectional shape including the support member. That is, the figure shows support members that support the cylindrical member 6 on its shaft at both axial ends of the cylindrical member 6. This support member is
Of course, it is sufficient to support and fix the cylindrical member 6 and the shaft as described above, and the axially both ends of the cylindrical member 6 are open except for the part where the support member is provided. Of course, the structure is such that a section is formed. For example, although the details are not shown in the drawings, in FIG. 2, there are openings at the left end and right end of the cylindrical member 6, which serve as inlets through which the developer outside the cylindrical member 6 is fed into the inside. and an opening serving as an outlet through which the developer inside is sent out to the outside, and a developer reflux path is configured such that the developer passes through these openings. Further, the reflux auxiliary means 6b shown in FIG. 2 is composed of spiral blades arranged in the same direction as the reflux promoting blades 6a on the outer periphery of the cylindrical member 6, but it may be replaced with, for example, a radial plate including a shaft. Also, instead of the propelling blade portion 7c protruding outward from the left end of the cylindrical member 6, the outer part of the radial plate including the shaft scrapes the developer into the center. A reflux smoothing effect can also be obtained by providing a scraping plate having a curved shape as shown in FIG. Furthermore, various shapes and structures as shown in FIGS. 3 to 5 can be used for the propulsion stirring blades of the screw-propelled rotating member 7 or the reflux promoting blades 6a on the outer periphery of the cylindrical member 6. can. When the shape and structure shown in FIG. 4 and FIG. 5 are used, the stirring action is increased more than when the shape and structure shown in FIG. 3 are used.

In the present invention, a propelling vane having a spiral direction opposite to that of the reflux promoting vanes on the outer periphery is provided inside the rotating cylindrical member 6, and the screw propulsion type rotating member 7
It is also possible to omit the replenishment toner, or even if the replenishment toner is sent to the vicinity of the filling opening at the inner entrance of the cylindrical member 6, it can be expected that the toner will be reliably fed inside. Then, the rotating cylindrical member 6
Needless to say, the shape and structure shown in FIGS. 3 to 5 can also be used for the propulsion blades provided inside the propeller. In addition, in the case where the screw propulsion type rotating member 7 is provided, the cylindrical member is fixed,
A conveyance means such as a screw conveyor may be provided around the developer for causing the developer to flow from right to left in FIG. A developing device in which a propelling blade is also provided inside the rotating cylindrical member 6 and the screw propelling type rotating member 7 is omitted has the advantage that the device can be made compact.

As is clear from the above description, according to the present invention, the replenished toner is sufficiently mixed with the developer before being supplied to the magnetic brush device, so that clear fog-free development can be performed. This reduces the occurrence of dirt inside the machine, and also prevents the developer from stagnation near the area where the developer is fed from the outside to the inside of the cylindrical member, allowing the developer to flow back in one direction. Since there is no collision of flows, there is little deterioration of the developer even if the reflux speed is increased.
Therefore, in order to improve image quality, conventional developing devices use developers with small particle sizes (for example, carrier particles with an average particle size of 10 to 20 μm, and toner particles with an average particle size of several μm), which are prone to insufficient mixing and deterioration. A number of excellent effects can be obtained, such as the fact that the device can be made more compact and can also be used effectively.

Example: Magnetic brush sleeve 2 outer diameter 30φ, rotation speed
100 rpm, the number of magnetic poles of the magnet body 3 is 8, the magnetic flux density of the magnetic poles is 1000 Gauss, the rotation speed is 1500 rpm, the developer removal member 4 is made of a magnetic stainless steel bar with a diameter of 5φ, and the gap with the magnetic brush sleeve 2 is 0.1 mm, developer regulation. The member 5 is made of a magnetic stainless steel rod with a diameter of 8φ, and the gap with the magnetic brush sleeve 2 is 0.5 mm.The reflux promoting blade 6a of the cylindrical member 6 is a screw blade as shown in FIG. 3, and the rotation speed is 100 rpm. The screw blades of the rotary member 7 are screw blades as shown in Figure 3, and the developing device shown in Figures 1 and 2 has a rotation speed of 200 rpm, and a ferrite carrier with an average particle size of 15μ and a screw blade with an average particle size of Development was carried out using a developer consisting of 5 μm of toner while replenishing the toner with the screw conveyor 8. The amount of developer in the developer reservoir 1a was controlled to be approximately at the level of the developer removing member 4 when the developer was stationary.

The development results were excellent, such as providing clear recorded images with excellent resolution and no fogging, and causing little staining inside the machine.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view in the direction perpendicular to the axis showing an example of the developing device of the present invention, Fig. 2 is a partial sectional view in the direction parallel to the axis, and Figs. FIG. 3 is a partial side view showing an example of a rotating member. 1...Casing, 2...Magnetic brush sleeve, 3
... Magnet, 4... Developer removing member, 5... Developer regulating member, 6... Cylindrical member, 7... Screw propulsion type rotating member, 8... Screw conveyor.

Claims (1)

[Claims] 1. In a developing device using a two-component developer, which is equipped with a developer agitating means having a cylindrical member in a developer reservoir and is adapted to replenish toner inside the cylindrical member, the inner side of the cylindrical member and the outside thereof, and the developer is arranged coaxially with the cylindrical member and on the outside of the cylindrical member, so that the developer on the outside of the cylindrical member flows inside the cylindrical member. An auxiliary means near the entrance of the cylindrical member into which the developer on the outside of the cylindrical member is conveyed in a direction opposite to the direction in which the developer on the outer periphery of the cylindrical member is conveyed. A developing device characterized by being provided with.