JPS6347871Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a dry developing device such as an electrophotographic copying machine.

A general example of a dry type developing device for an electrostatic latent image formed on a latent image carrier such as a photoreceptor drum through a predetermined process in an electrophotographic copying machine etc. is explained with reference to FIG. A magnet 3 having a plurality of magnetic poles is provided inside a non-magnetic cylindrical sleeve 2 which is rotatably arranged with a small gap with respect to the body 1, and is formed along the circumferential surface of the sleeve 2. The magnetic developer 5 is supplied from the hopper 4 to the sleeve 2, and is attracted to the surface by the magnetic force of the magnet 3.The thickness of the developer layer is regulated by the developer amount regulating plate (doctor) 6, and the sleeve 2 is moved in the direction indicated by the arrow. By the rotation, the developer is supplied to the latent image carrier 1, and developed by being attracted to the electrostatic latent image formed thereon. The developer that did not contribute to development returns to the hopper 4 while being adsorbed by the sleeve 2, and is uniformly stirred and mixed with the developer in the hopper by the stirring member 8, thereby regulating the amount of developer. It circulates repeatedly through member 6. When the developer in the hopper 4 is consumed by development, it is successively replenished by its own weight from, for example, a cartridge type developer replenishing container 7, which is detachably provided in contact with the hopper 4.

Replenishment of developer from the replenishment container 7 and supply to the developer carrier 2, which is generally used in a dry developing device, is as follows:
Since this is done by powder flow, in order to improve the fluidity, the bottom of the supply container 7 and the hopper 4 are
The inner wall 9 constituting the bottom surface of the sleeve 2 is made of a smooth material and is moderately sloped downward toward the sleeve 2. As a result, as the amount of developer in the hopper 4 decreases, the developer in the replenishment container 7 flows down into the hopper 4 from the replenishment port 7a as shown by arrow b in the figure, and is carried by the sleeve 2. The developer is stirred and mixed by the stirring member 8 with the developer that has returned from the developing section into the hopper 4 along the arrow a.

The inner wall 9 of the hopper 4 has a developer remaining amount detection means 1.
0 is provided, and a supply container 7 and a hopper 4 are provided.
If the developer in the container runs out, it is detected and displayed, and the developer supply container 7 is brought to the position 7' indicated by the chain line in the figure and replaced with a container filled with developer. When the replenishment container full of developer is returned to the set position shown by the solid line, a considerable amount of the developer in the container is thrown out by its inertia into the hopper 4 from the replenishment port 7a as shown by arrow C, and is thrown onto the hopper inner wall 9. Due to the acceleration due to its inertia and the strong magnetic attraction force of the magnet 3 inside the sleeve 2, it rapidly slides down the slope of the hopper inner wall 9 and is supplied onto the sleeve all at once, or the hopper inner wall 9 The developer may overflow from the gap 11 between the lower end of the sleeve 2 and the like, fall and scatter into the machine, or adhere to the image forming surface of the latent image carrier 1, resulting in an abnormal image.

This invention eliminates the above-mentioned drawbacks of conventional developing devices of this type. During development, the supply of developer to the sleeve is not obstructed, and when the developer supply container is replaced, a large amount of developer is dropped from the supply container onto the inner wall of the hopper. An object of the present invention is to provide a developing device in which there is no risk of developer overflowing from a hopper and falling into the machine and causing abnormal development.

Hereinafter, the present invention will be explained in detail based on drawings showing embodiments thereof.

FIG. 2 is a diagram showing an embodiment in which the present invention is applied to the conventional developing device explained in FIG. A means is provided for reducing acceleration due to inertial force during developer replenishment over the entire width in the axial direction. In this embodiment, as a means for this purpose, a sheet 12 in which loop-shaped fibers used for the female tape of commercially available magic tape are implanted is pasted to the inner surface of the inner wall 9.

Since this device is constructed as described above, in a steady state during copying, the developer is contained in the hopper 4 to a certain level or more, so the loop-shaped fiber sheet 12 attached to the upper surface of the inner wall 9 The fiber loops are completely covered with the developer, and the gaps between the fiber loops are filled with developer without any gaps, creating a clogging condition. The upper surface of the inner wall 9 rises by the thickness of the loop-shaped fiber sheet 12. This can be done smoothly and stably without any inconvenience.

However, the developer in the supply container 7 runs out, the developer in the hopper 4 gradually decreases, and by the time the developer remaining amount detection means 10 is activated, the fiber loops of the loop fiber sheet 12 are clogged. Since the developer is also sucked toward the sleeve 2 and disappears, the gap between the fiber loops is no longer clogged.
Therefore, when the developer replenishment container 7 is replaced, even if a large amount of developer falls from the replenishment port 7a of the new replenishment container onto the inner wall 9 with a considerable inertial force, the developer will be distributed between the fiber loops. The acceleration due to inertial forces entering the sleeve 2 in the direction of the sleeve 2 is reduced by the fiber loop. As a result, the developer that has fallen onto the hopper inner wall 9 is prevented from sliding down at high speed due to the inertial force at the time of falling and the magnetic attraction force of the magnet 3, and the overflowing phenomenon of the developer from the hopper 4 can be prevented. I can do it.

In the above embodiment, as a means for reducing the acceleration of the developer falling onto the inner wall of the hopper when replacing the developer supply container, a sheet in which loop-shaped fibers used in magic tape are implanted is attached to the inner wall surface. In addition, as shown in FIG. 3, a similar effect can be obtained by attaching a flocked brush 13 in which bristles with appropriate density and elasticity are implanted to the hopper inner wall 9, and as shown in FIG. As shown,
This objective can also be achieved by providing protrusions 14 at appropriate intervals on the inclined inner wall surface and having a height corresponding to the thickness of the developer layer that is intended to prevent sliding down, in a direction perpendicular to the direction in which the inner wall 9 is inclined. be done.

As described above, according to the present invention, with a simple configuration,
This prevents developer from overflowing from the hopper when replacing the developer replenishment container without interfering with the smooth supply of developer to the developer holding means during development. This is effective in preventing contamination caused by falling and scattering and the occurrence of abnormal images.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a conventional developing device.
FIG. 2 is a cross-sectional view showing an embodiment in which the present invention is applied to the above-mentioned developing device, and FIGS. 3 and 4 are cross-sectional views showing other embodiments of the acceleration reducing means of the present invention, respectively. DESCRIPTION OF SYMBOLS 1...Latent image carrier, 2...Developer holding means (sleeve), 3...Magnet generator (magnet), 4...Developer supply means (hopper), 7...Developer supply container, 9... ...Hopper inner wall, 12, 13, 14...
Acceleration reduction means.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A developer holding means that includes a magnetic field generating device and is rotatably disposed with a small gap with respect to the latent image carrier, and this developer holding means The developer supplying means receives and stores the developer from the developer supply container, and the stored developer is transferred to the developer holding means by its own weight and the magnetic field. In a developing device configured as a hopper having an inclined inner wall that allows the developer to flow down toward the developer, the developer supplying hopper has an inclined inner wall surface that reduces the acceleration of the developer having a predetermined thickness on the wall surface. A developing device characterized by being provided with means. (2) A utility model characterized in that the means for reducing the acceleration of the developer described above is comprised of a sheet in which loop-shaped fibers with a height corresponding to the layer thickness of the developer are attached to the inclined inner wall surface. A developing device according to claim 1. (3) The developer acceleration reducing means is characterized in that a flocked brush having bristles of a height corresponding to the layer thickness of the developer is provided on the inclined inner wall surface. A developing device according to claim 1 of the patent registration claim. (4) The developer acceleration reducing means is provided with protrusions having a height corresponding to the layer thickness of the developer at appropriate intervals on the inclined inner wall surface in a direction perpendicular to the direction of inclination thereof. A developing device according to claim 1 of the utility model registration claim, characterized in that the developing device comprises: