JPS6398680A - Developing device for electronic copying machine - Google Patents

Abstract

PURPOSE:To improve the conveying ability for and the electrostatic charging performance of toner and to prevent toner from falling and scattering by putting a particle agitating material which is larger in particle size than toner in a toner hopper. CONSTITUTION:The particle agitating material 10 which is larger in particle size than the toner is put in the toner hopper 8. The particle agitating material 10 has >=100mum particle size and is much larger than the toner 9, so it is cut off by an elastic blade 5 and not conveyed to a developing roller 2. The particle agitating material 10 can charges toner 9 being agitated electrostatically and preliminarily, and the toner is charged electrostatically to some extent before being carried by the developing roller 2. Consequently, the quantity of electrostatic charging of the toner conveyed to the developing roller 2 increases sufficiently and the falling and scattering of the toner are reduced.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an improvement in a developing device for electronic copying, and more specifically, an electronic copying machine with improved toner transportability and charging performance. The present invention relates to a developing device.

(Prior Art) Generally, a developing device for electronic copying is formed as shown in FIG.

That is, in FIG. 4, a toner layer holding member (developing roller) 2 whose surface has been roughened by sandblasting etc.
An elastic blade 5 held by a holding member 6 is in contact with the electrostatic latent image formed on the electrostatic holding member (photosensitive drum) 1 facing the toner layer holding member 2, as shown in the figure. Visualization is achieved by supplying a developing bias from a developing bias power source that is not used.

The conditions at this time are, for example, latent image potential = 600 volts, interval between toner layer holding member 2 and electrostatic holding member 2: 250 microns, DC voltage of developing bias: 200 volts, AC voltage: 2. OKV, a weight voltage with a frequency of 3 KHz is used.

Further, the residual toner on the toner layer holding member 2 passes through the collection blade 7 and is collected into the toner hopper 8 .

Furthermore, the toner electrostatically adhered to the toner layer holding member 2 is scraped off by a scraping roller 3 and returned into the toner hopper 8.

Specifically, this development method uses a high-resistance non-polar component toner, and the toner is charged by I! between the toner and the toner layer holding member 2 and the toner and the elastic blade 5. This is done by frictional charging.

Further, the toner 9 is stirred and conveyed by the stirring row 54 and the scraping roller 3, and the stirred toner 9 is conveyed to the vicinity of the toner layer holding member 2.

The surface of the toner layer holding member 2 is sandblasted to improve the conveyance of the toner 9 by sandblasting or the like.
The surface is roughened to a roughness of about 0μ1llR2.

Therefore, unlike two-component development or magnetic-component development, this type of developing device does not require magnetic conveyance of toner, and can perform development using high-resistance non-magnetic component toner. It has a simple structure, is small and lightweight, and is not only economically advantageous, but also is non-magnetic, so it can be said to be the most suitable developing method for multicolor development.

(Problems to be Solved by the Invention) However, in the conventional developing device shown in FIG. The used toner could not be used effectively and was uneconomical.

Further, since the toner is charged only by the elastic blade 5, the amount of charge is insufficient, and there is a fear that fogging and toner scattering may occur.

The present invention was achieved as a result of studies aimed at solving the problems of the conventional developing device described above.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device for an electronic copying machine that improves toner transportability and charging performance and effectively prevents toner from falling off or scattering.

[Structure of the Invention] (Means for Solving the Problems) That is, the present invention conveys toner in a toner hopper onto a toner layer holding member, brings an elastic blade into contact with the toner layer, and forms a monocomponent toner layer. In a developing device that visualizes an electrostatic latent image formed on an electrostatic holding member facing the toner layer holding member, a granular stirring material having a particle size larger than the toner particle size is contained in the toner hopper. The gist of the invention is a developing device for an electronic copying machine, which is characterized by having a built-in.

(Function of the Invention) The developing device of the electronic copying machine of the present invention incorporates the granular stirring material having a particle size larger than the toner particle size in the toner hopper. By scraping off the adhered toner, it becomes possible to use the toner effectively, and the amount of charge of the toner is increased, making it possible to effectively prevent the toner from falling off or scattering.

(Description of Embodiments) Hereinafter, one embodiment of the developing device for an electronic copying machine of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side cross-sectional explanatory view showing an electronic copying machine to which the developing device of the present invention is applied, FIG. 2 is a cross-sectional explanatory view of the developing device of the present invention, and FIG. 3 is a cross-sectional explanatory view of the elastic blade portion. .

In FIG. 1, an electronic copying machine incorporating a developing device 14 of the present invention operates as follows.

That is, first, the electrostatic holding member (photosensitive drum) 1 is charged with the charging charger 12, and then the optical system 13 is used to illuminate a document (not shown) placed on the document table 22. The light forms an electrostatic latent image on the photoreceptor drum 1 by the imaging lens eye 23, which is then formed as a visible image on the photoreceptor drum 1 by the developing device 14 of the present invention.

On the other hand, the visible image is transferred to the copy paper (not shown) conveyed from the paper feed cassette 15 or the manual feed tray 16 by the transfer device 17, and the image is further fixed to the copy paper by the fixing device 18. The paper is discharged to the paper discharge tray 19.

The toner remaining on the photoreceptor drum 1 after transfer is cleaned by a cleaning device 20, and the charge remaining on the photoreceptor drum 1 is further removed by a discharge lamp 21.

The developing device 14 of the present invention described above has the same overall structure as the conventional developing device shown in FIG. 4, but as shown in FIGS. 2 and 3, This embodiment is different from the conventional example described above in that the toner hopper 8 contains a granular stirring material 10 having a larger particle diameter than the toner and being more granular.

The granular stirring material 10 used in the present invention has a particle size of 10
Since it is 0 μm or more, which is sufficiently large compared to the toner 9, it is blocked by the elastic blade 5 as shown in FIG.
It is not conveyed to the developing roller 2.゛The developing roller 2 is a cylindrical roller made of aluminum or the like with a mirror finish, and the surface is roughened by sandblasting or the like, and the surface roughness of the roughened portion is 0.5. A range of 10.0 μm RZ is suitable. The most suitable developing roller 2 is one whose surface is roughened and then further protected by electroless nickel plating or the like.

A metallic elastic blade 5 made of stainless steel or the like is in contact with the developing roller 2, and the toner 9 is charged by friction with the developing roller 2 and the elastic blade 5, and is deposited on the developing roller 2. A toner layer (electrostatic latent image forming area) is formed.

However, in the developing device of the present invention, in the toner hopper 8, the toner 9 is stirred together with the granular stirring material 10 by the stirring roller 4, so that the toner adhering to the inner wall of the toner hopper 8 is mixed with the stirring material 10. Since the toner is scraped off by the toner, stirred and conveyed together with the replenishment toner, the toner can be used effectively and is extremely economical.

Further, the granular stirring material 10 can preliminarily charge the toner 9 being stirred, and the toner 9 can be charged by the elastic blade 5.
Since the toner is already charged to some extent before it is charged by the developing roller 2, the amount of charge on the toner conveyed to the developing roller 2 is sufficiently high, which not only reduces toner falling off and scattering, but also provides stable copy image quality. becomes possible.

As described above, the granular stirring material 10 has a particle diameter of 100μ1 or more, which is sufficiently large compared to the toner 9, so that it is always contained in a constant amount in the toner hopper 8 without passing through the elastic blade 5. Ru. Therefore, there is no need to replenish the granular stirring material 1o, and its stirring performance can also be kept constant.

[Effects of the Invention] As explained above, the developing device of the electronic copying machine of the present invention incorporates the granular stirring material having a particle diameter larger than the toner particle diameter in the toner hopper. The toner scrapes off the toner adhering to the inner wall of the toner hopper, making it possible to use the toner effectively.Moreover, the stirring and conveying effects are enhanced, and the amount of charge on the toner is improved.

Therefore, toner falling off and scattering can be effectively prevented.
Not only is there no occurrence of defective copies such as stains on the copy paper, but it is also possible to obtain excellent copy image quality.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional explanatory view showing an electronic copying machine to which the developing device of the present invention is applied, FIG. 2 is a cross-sectional explanatory view of the developing device of the present invention, and FIG. 3 is a cross-sectional explanatory view of the elastic blade portion. , FIG. 4 is a cross-sectional explanatory view of a developing device of a conventional electronic copying machine. 1... Electrostatic holding member (photosensitive drum) 2... Toner layer holding member (developing roller) 3... Scraping roller 4... Stirring roller 5... Elastic blade 6... Elastic blade Holding material 7... Collection blade 8... Toner hopper 9... Toner 10... Granular stirring material 14... Developing device

Claims (3)

[Claims] (1) The toner in the toner hopper is conveyed onto the toner layer holding member, an elastic plate is brought into contact with the toner layer to form a monocomponent toner layer, and an electrostatic plate is formed on the electrostatic holding member facing the toner layer holding member. 1. A developing device for an electronic copying machine that visualizes an electrostatic latent image, characterized in that a granular stirring material having a particle diameter larger than that of toner is built into the toner hopper. (2) A developing device for an electronic copying machine according to claim (1), wherein the granular stirring material is regulated by an elastic blade and is not conveyed onto the toner layer holding member. (3) Claims (1) and (2) characterized in that the particle diameter of the granular stirring material is 100 μm or more.
) A developing device for an electronic copying machine according to item 1.