JPS5916935Y2 - magnetic brush developing device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a magnetic brush developing device.

In a magnetic brush developing device, a two-component developer consisting of toner and carrier is sucked onto the surface of a magnetic roll to form a brush, and this is brought into contact with the electrostatic latent image forming surface to visualize the developer. Since it is necessary to mix the toner and carrier inside and make the concentration uniform, a dynamic stirring method using a rotating screw (Utility Model Application Publication No. 50-6645, Japanese Patent Application Publication No. 49-198) was developed.
No. 06331) and a static stirring method in which the end of the scraping plate is shaped like a comb to change the fall time of the developer (Utility Model No. 5).
1-60253) has been proposed.

However, the former dynamic agitation method has a complicated structure as it requires a power transmission member and a screw member, and fatigue of the developer due to forced agitation affects the image, reducing the frequency of developer replacement. It has many disadvantages.

On the other hand, the latter static stirring method has a simple structure and does not cause fatigue of the developer, but the comb-shaped notches cannot make much difference in falling time, and the stirring effect is poor, resulting in poor mixing and It has the disadvantage of not being able to achieve uniform density.

The present invention aims to eliminate the above-mentioned drawbacks by providing a device that has a simple structure, adopts a static stirring method that does not cause fatigue of the developer, and provides a large stirring action. .

Hereinafter, the present invention will be explained with reference to illustrated embodiments.

FIG. 1 shows an embodiment of the present invention, and reference numeral 3 in the figure refers to a magnet holder 2 that rotates on the circumference of a magnet holder 2 in response to a driving force from an external drive source, and a magnetic This is a developing sleeve that brings the brush tip into sliding contact with the surface of the photoreceptor drum 9 to visualize the latent image formed on the drum 9. On the falling side, there is a cross-sectional funnel equipped with a receiver part 51 that catches the entire amount of the developer that falls, and a discharge port 52 that allows only a smaller amount of developer to be discharged than the amount that flows into the receiver part 51. An overflow member 5 having a shape extends along the axial direction of the developing sleeve 3.

In the embodiment described above, the developed developer that has fallen from the developing sleeve 3 is transferred to the receiving portion 51 of the overflow member 5.
However, a part of these fluids gradually descends inside the member 5 and falls from the discharge port 52, whereas the remainder that exceeds the discharge amount flows directly down from the receiving portion 51. There is a large difference in falling time between the two, and any partial excess or deficiency of developer that occurs during the development supply stage or the development stage is uniformly leveled out by this static stirring.

In the embodiment shown in FIG. 2, guide plates 53 are provided on both sides of the overflow member 5. According to this, the overflowing developer flows out from the discharge port 52 before development and is mixed with the guide plate 53. This can further encourage

In the embodiment shown in FIG. 3, the upper edge of one or both sides is formed into a comb shape 54, and the teeth of the comb shape 54 provide an agitation effect that distributes the overflowing developer to the left and right.

In yet another embodiment shown in FIG.
1 is partitioned by providing gaps 55 in the longitudinal direction, and according to this, stirring can be performed not only in the left-right direction but also in the front-back direction.

As described above, according to the present invention, the overflow member is provided in the developer falling flow path from the magnetic brush forming member, so that the amount of discharge is less than the amount of inflow. It is possible to create a large difference in falling time between the developer that descends inside and is discharged from the discharge port and the developer that falls directly from the upper edge of the overflow member, ensuring that agitation is carried out reliably. be exposed.

Moreover, since static agitation is performed by the falling of the developer itself rather than forcible agitation using driving force, the device is simple, there is no fatigue of the developer agent, and there is no effect on images even after long-term use. It has excellent effects as a magnetic brush developing device, such as no adverse effects.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the device of the present invention, Fig. 2 is a sectional view showing the main parts of another embodiment, and Figs. 3 and 4 are perspective views showing the main parts of still another embodiment. It is. 1...Magnetic brush developing device, 5...Overflow member, 52...Discharge port.

Claims (1)

[Scope of utility model registration request] In the falling path of the developed developer, there is a receiver part that catches the entire amount of the falling developer, and the receiver part has a funnel-shaped cross-section with a discharge port that discharges a smaller amount of developer than the amount that flows into the part. A magnetic brush developing device comprising an overflow member extending in the developing width direction.