JPS58166369A - Developing device - Google Patents

Abstract

PURPOSE:To collapse the lump (floc) of a magnetic toner and to prevent the generation of the lump by providing a comblike plate on the upper stream side of a plate for regulating the thickness of a developer layer. CONSTITUTION:A one-component magnetic toner 10 is contained in a hopper 5, and is conveyed to a developing region by the rotating magnetic force of a magnet roll 2 which rotates in a sleeve 1. A regulating plate 6 which regulates the amt. of earing (amt. of holding) of the toner is provided between the developing region and the hopper at a spacing A from the sleeve 1, and a comblike plate 8 which is formed of an elastic member such as a resin, and of which one end contacts the surface of the sleeve and the other end is mounted to one side wall forming the hopper 5 is provided on the upper stream of the plate 6. When the toner passes through the plate 8, the toner is agitated spirally and the toner in a flocculated state is collapsed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device for visualizing an electrostatic latent image formed on a photoreceptor in an electrophotographic copying machine, and in particular to a developing device made of a magnetic one-component toner. The present invention relates to a developing device that performs development using a developer.

The developing device of an electrophotographic copying machine uses a two-component developer consisting of a colored pigment toner and a magnetic carrier such as iron powder.The toner is charged electrostatically on the photoreceptor by frictional charging between the toner and the carrier. One type uses a method in which the toner is charged to the opposite polarity to the latent image and adheres to the electrostatic latent image, and the other uses a one-component developer in which the toner itself has magnetic properties. There is a method in which toner is electrostatically attracted to an electrostatic latent image by applying dielectric polarization or the like. A magnetic brush development method is widely used as a developing means for conveying the two-component or -component developer to the development area of the photoreceptor on which the electrostatic latent image is formed and attaching toner. . This development method has advantages over the cascade development method, such as a simpler structure and smaller size. The magnetic brush development method generally uses a developing roller consisting of a cylindrical sleeve made of a non-magnetic material and a magnet roller rotatably installed inside the ribbed sleeve. A developing device having the above-mentioned structure has a structure in which the carrier or magnetic toner is attracted onto the sleeve by magnetic force through rotation, and the developer is conveyed to the developing area.
In those using a two-component developer, a means for stirring the developer is required in addition to the developing roller in order to triboelectrically charge the toner. However, those using a -component type developer do not need to provide stirring means for triboelectrically charging the toner, and can be more compact than two-component type developing devices.

Here, a problem with a magnetic brush type developing device that uses a -component type developer (hereinafter referred to as toner) is the agglomeration of the toner. That is, the fluidity (angle of repose) of -component magnetic toner varies depending on the content of magnetic powder, the type of resin, etc., but since it is a fine particle, it clumps when passing through a narrow area. Further, the toner particles may be frictionally charged with each other or between the toner particles and the sleeve, and may be electrostatically aggregated, or the toner particles may be magnetized and aggregated by the magnetic force of the magnet roller.

This makes it impossible to obtain a good image. Normally, a regulating means is provided to regulate the amount of toner held on the sleeve of the developing roller, and this regulating means, the path for conveying the toner to the developing roller, and the developing area are very narrow, and the above-mentioned toner clumps are likely to occur. Moreover, it was difficult to prevent this.

In view of the above-mentioned drawbacks, the present invention provides a developing device in which toner does not clump, and achieves the object with a simple structure.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing a specific example of a developing device according to the present invention. In the figure, 1 is a non-magnetic cylindrical sleeve;
Reference numeral 2 denotes a magnet roller which is rotatably provided within the sleeve and whose outer circumferential magnetic poles are sequentially magnetized, and these constitute a developing roller. Reference numeral 3 denotes one-component magnetic toner held on the sleeve 1 by the magnetic force of the magnet roller 2;
and a photosensitive drum on which an electrostatic latent image is formed. The toner 3 is stored in a replenishment hopper 5, and the toner 3 is stored in an opening 10 at the bottom of the hopper 5.
It had a sloped surface with an angle R provided at . It flows through the inclined plate 9 and is sequentially supplied onto the sleeve l by the magnetic force of the magnet row 22. On the other hand, a developing area facing the photoreceptor drum 4 and a hopper 5
A regulating plate 6 is arranged at a distance A from the sleeve 1 to regulate the amount of spikes (holding amount) of the toner 8 supplied onto the sleeve 1 . The regulating plate 6 controls the amount of toner 8 held on the sleeve 1 in order to always convey a constant amount of toner to the development area where the toner 8 contacts the surface of the photoreceptor drum 4 . Before the regulating plate 6 regulates the amount of toner 3 held, that is, at the rear of the hopper 5, a plate 8 is provided to prevent the toner 8 from clumping in the present invention. This plate 8 is made of an elastic member such as resin, and has one end in contact with the three 3=1, and the other end is a support plate 7 fixed to one side wall 11 forming the hopper 5.
is supported by

Further, as an example of the plate 8 is shown in FIG. 2, the distal end portion in contact with the sleeve 1 is formed into a comb shape with notches having a width D and a length B at a constant pitch. In the figure, C is the width of the convex portion in contact with the sleeve 1.

The comb-shaped plate 8 has one end fixed to one side wall of the hopper 5 via the support plate 7, but it can be placed anywhere as long as it is between the regulation plate 6 and the hopper 5. You can.

The operation of the device configured as described above will be explained for the purpose of understanding the present invention.

The toner 8 in the toner supply hopper 5 now flows due to the inclination angle R of the inclined plate 9 and the fluidity (angle of repose) of the toner 3.
It is supplied onto the sleeve 1 by the magnetic force of the magnet roller 2, and as the sleeve 1 rotates in the direction of arrow V, it is conveyed to the developing area. At this point, the toner 8 passes through the regulating plate 6 and the developing area, making it easy to clump. This depends on the content of magnetic material in toner 3, the type of resin, etc., and the fluidity (
Although the angle of repose) is different, the toner 3 is frictionally charged with each other or the toner 8 and the sleeve 1 and aggregated electrostatically, or the toner 3 is magnetized and aggregated by the magnetic force of the magnet roller 2. However, in the present invention, a comb-shaped plate 8 is provided between the regulation plate 6 and the hopper 5.
is provided to break up the agglomeration of toner generated by passing the toner through the comb-shaped plate 8 and to prevent the toner from forming. In this case, the bundled toner particles are swirled while passing through the comb-shaped plate 8, and the aggregated toner particles are broken down. This resolved toner 8 is smoothly conveyed to the development area as a fixed amount of toner via the regulating plate 6. Therefore,
In the development area, the toner 3 is subjected to development in a stable state without clumping or agglomeration.

As an example, the distance A between the toner regulating plate 6 and the sleeve 1 is 0.2 to 1.0, and the weight ratio of iron oxide powder and styrene resin is 5:5 or 6:4, and the particle size is 5 to 80 μm. Using a toner 8 with an angle of 40 to 45 degrees, a magnetic roller 2 of 1000 Gauss, and a comb-shaped plate 8 of 100 μm thick made of polyester resin, B=5fi, C=2.
When the processed toner with W and D = 2 ml and 1 ml was used, no clumping of toner 3 was observed, and the toner was smoothly conveyed, resulting in a good image. Although the specific example of the present invention shown in FIG. 1 uses a magnet-fixed sleeve rotating system, the present invention may also be implemented with a magnet-rotating sleeve fixed or a magnet sleeve rotating in reverse.

As explained above, according to the developing device of the present invention, toner clumping that occurs in the path for conveying toner to the developing area is prevented, toner conveyance is performed smoothly, and the amount of toner conveyance can be accurately controlled. It can always provide clear images.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a specific example of the developing device according to the present invention.
FIG. 2 is a plan view showing a specific example of the comb-shaped plate of the present invention in FIG. 1. 1 Ni sleeve, 2: Magnet row 9-. 3: magnetic toner, 4: photoreceptor, 5: hopper, 6: regulating plate, 7: supporting plate, 8: comb-shaped plate, 11: one side wall forming the hopper.

Claims (1)

[Claims] 1. Using a developing roller configured by rotatably providing a magnetic roller inside a cylindrical sleeve made of a non-magnetic material, by rotating the sleeve and the magnetic roller relative to each other, magnetism is developed. In a developing device that holds a one-component developer on a sleeve and transports it to a developing area facing a photoreceptor on which an electrostatic latent image is formed, the amount of developer held on the sleeve of the developing roller is regulated. A developing device characterized in that a comb-shaped plate is provided between a regulating plate for storing the developer and a hopper for accommodating the developer, and facing the developing roller. 2. The developing device according to claim 1, wherein a comb-shaped plate is provided on one side wall of the hopper.