JPS6232301Y2 - - Google Patents

Description

[Detailed description of the invention] The invention relates to a developing device of an electrophotographic copying machine.
In particular, the present invention relates to improvements in a developing device using a one-component developer.

Generally, the developing means of an electrophotographic copying machine is as follows:
Cascade, magnetic brush, etc. are the mainstream and have been commercialized. In the former cascade developing means, the device itself tends to be large in size, and there are many disadvantages such as surrounding dirt due to scattering of toner particles and poor image quality in reproducing halftones. On the other hand, developing means using a magnetic brush is advantageous in high-speed copying machines because the device itself is compact, the reproducibility of halftones is good, and there is little scattering of toner particles. Based on these advantages, they are rapidly becoming popular these days, but the mainstream is a developer composed of two components: a carrier made of iron powder and a colored toner that is charged by friction when it slides on the carrier. is doing.

However, a developer composed of two components has poor durability of the carrier itself, and has a large influence on images due to physical or chemical deterioration phenomena.
Therefore, it is necessary to periodically replace the entire surface of the developer. Furthermore, unless a developer can be constructed that has a density distribution by uniformly supplying a certain amount of colored toner and by uniform stirring, it will not be possible to obtain uniform density over the entire surface even if images are freely produced. Especially in high-speed copying machines, the consumption of colored toner varies depending on the type of document, so for example, during large-volume copying, when there is overtoning, fogging occurs, and conversely, when the amount of colored toner decreases, the density decreases and blurred images become noticeable. .

The present invention provides a developing device that eliminates the above-mentioned drawbacks and obtains good copied images by using a one-component magnetic toner (hereinafter referred to as toner) as a developer, which is constructed by integrating the carrier and colored toner. It is something. This invention can be used as a developing roller of a developing device.
It consists of a rotatable multi-polar permanent magnet whose circumferential surface is covered with a non-magnetic sleeve.The magnetic force of the permanent magnet holds the toner on the sleeve surface, and the rotation of the permanent magnet transports the toner. This is an improvement on this device.

The problem here is toner clumping. That is, one-component magnetic toner has different fluidity (angle of repose) depending on the content of the magnetic substance, the type of resin, etc., and since it is a fine particle, it clumps when passing through a narrow area. This poses a problem in toner conveyance, making it impossible to supply sufficient toner to the developing roller. Furthermore, the toner clumps up, making development impossible and making it impossible to obtain a good image. Normally, a regulating means is provided for regulating toner adhesion in excess of the amount of toner that adheres to the sleeve of the developing roller. However, the above-mentioned toner clumps are likely to occur, and this cannot be prevented.

In view of the above drawbacks, the present invention provides a developing device that does not cause toner clumping, and achieves its purpose with a simple structure.

The present invention will be described in detail below with reference to the drawings.
The figure is a sectional view showing an example of the developing device according to the present invention. In the figure, 1 is a cylindrical sleeve made of a non-magnetic material, and 2 is a magnet roller which is rotatably provided within the sleeve and whose outer circumferential magnetic poles are sequentially magnetized with different magnetic poles, and these constitute a developing roller. . Reference numeral 3 designates a one-component magnetic toner that is attracted onto the sleeve by the magnetic force of a magnet roller. Reference numeral 4 designates a photoreceptor drum located at a distance equal to or less than the amount of adhering toner from the sleeve 1, on which an electrostatic latent image is formed.

The toner 3 is stored in a replenishment hopper 5, flows through an inclined plate 7 having an inclined surface with an angle R provided in an opening 6 at the bottom of the hopper 5,
and is sent to the conveying plate 8, which is connected at one end to the conveyor plate 8. The conveying plate 8 has a tip extending to the developing roller portion and being folded back, and one end is fixed to the inclined plate 7 so as to be able to move up and down freely. The tip of a toner adhesion amount regulating plate 9 whose other end is fixed to the side wall of the hopper 5 is located between the conveying plate 8 and the sleeve 1. Further, a magnetic body 10 is fixed to the back surface of the conveyance plate 8, which is located during the action of the rotating magnetic field of the magnet roller 2 and causes the conveyance plate 8 to vibrate.

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

Now, the toner 3 in the toner supply hopper 5 is determined by the inclination angle R of the inclined plate 6 and the fluidity (angle of repose) of the toner 3.
As a result, it flows from the A position of the opening 6 to the B position of the transport plate 8. Therefore, as the magnet roller 2 of the developing roller rotates in the direction of arrow V, the toner 3 passes through the folded portion of the conveying plate 8 from position B and is attracted onto the sleeve 1 via the regulating plate 9.
At this time, the toner 3 rotates on the sleeve 1 in the direction opposite to the rotational direction of the magnet roller 2 and is transported to the developing area of the photosensitive drum 1, and the amount of toner 3 adsorbed to the sleeve 1 is determined by the tip of the regulating plate 9. is regulated. Here, when the toner 3 passes through the conveyance path C between the conveyance plate 8 and the regulation plate 9, the toner 3 adheres to the regulation plate 9 and tends to clump. This is because the fluidity of the toner differs depending on the content of the magnetic substance in the toner 3, the type of resin, etc. However, in the present invention, the magnetic body 1 located in the rotating magnetic field of the magnet roller 2
0 causes the conveying plate to vibrate in the direction of arrow E. This vibration breaks up the toner clumps that tend to occur,
It also prevents the formation of lumps. In this case, the amplitude of vibration is large when the rotation of the magnet roller 2 starts, and becomes a slight vibration when the rotation becomes steady. Therefore, the vibration of the conveying plate 8 can break up toner clumps and prevent the formation of clumps, and the toner 3 can be smoothly conveyed, and the regulating plate 9 can correctly regulate the amount of toner adsorbed onto the sleeve 1.

As one example, the distance between the toner regulating plate 9 and the conveying plate 8 is 2.0 to 3.0 mm, the distance between the toner regulating plate 9 and the sleeve 1 is 0.5 to 2.0 mm, and iron oxide powder and iron oxide powder are set in the toner composition. Ratio of low molecular weight polyethylene resin is 100:100 or 100:50, particle size is 5-40μ
m, and the toner 3 has an angle of repose of 40 degrees, and when a 1000 glass magnet roller 2 and a 300 glass permanent magnet are used for the magnetic body 10, no clumping of the toner 3 is observed and smooth toner transport and control is achieved. I was able to do that.

As explained above, according to the developing device of the present invention,
By providing a conveying plate on the toner conveying path from the hopper to the developing roller and vibrating the conveying plate, it is possible to prevent the toner from clumping, including during conveyance of the toner that is attracted to the developing roller. In this case, a magnetic material is provided on the back surface of the conveyor plate, and the conveyor plate can be vibrated by the rotating magnetic field of the developing roller, which can effectively prevent toner from clumping without causing any problems in conveying the toner, and can absorb the amount of toner. The amount can also be accurately regulated using a regulating plate, making it possible to always provide clear images.

[Brief explanation of the drawing]

The figure is a sectional view showing a specific example of the developing device according to the present invention. 1: sleeve, 2: magnet roller, 3: toner, 4: photoreceptor, 5: hopper, 8: conveyance plate,
9: Regulating plate, 10: Magnetic material.

Claims (1)

[Claims for Utility Model Registration] 1. A one-component developer containing a magnetic material in a resin using a developing roller having a rotatable magnet roller inside a sleeve made of a non-magnetic material; A hopper that accommodates the developer and a developing roller are used in a device that performs development by adsorbing the developer onto the sleeve and conveying the developer to a developing area facing the photoreceptor on which an electrostatic latent image is formed. a developer conveying plate movably provided between the developer conveying plate and the developing roller; a regulating plate positioned between the developer conveying plate and the developing roller and regulating the amount of developer attached on the sleeve of the developing roller; A plate is provided on a non-conveying surface opposite to a conveying surface of the developer conveying plate for conveying the developer, and is provided under the action of the rotating magnetic field of the magnet roller, and the developer is conveyed by the rotating magnetic field of the magnet roller. A developing device comprising a magnetic material that vibrates a plate. 2. The developing device according to claim 1, wherein the magnetic material is a magnet.