JPS58115450A - Developing method of electrostatic image - Google Patents

Abstract

PURPOSE:To obtain a picture having high density and high contrast, and having no ground fog, on a photosensitive body, by ununiformly providing a magnetic body on a rotating developing sleeve, and varying a magnetic field formed by a permanent magnet which is in the inside of the sleeve. CONSTITUTION:When an electrostatic latent image part of an electrophotographic photosensitive drum 1 reaches a position of a developing part 3 of a developing device 2, it is carried by a developing sleeve 4 having a magnetic body 5 which has been provided discontinuously on its surface, and is developed and made visible by a developer 11 for forming a brush, in the developing part 3. In this case, a magnetic field formed by a fixed developing permanent magnet 6 is disturbed by the magnetic body 5 provided discontinuously on the developing sleeve 4, and the magnetic field is varied by rotation of the developing sleeve 4, therefore, disturbance is generated in a developer of the developing part 3, an opportunity for contacting with a toner is expanded, the toner adheres enough to a picture part, and a picture of high density is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic MAW method in an electrostatic recording device, and more particularly to an electrostatic image developing method in which a magnetic brush developing method is improved to improve image quality.

In electrostatic recording devices such as dry type electrophotographic copying machines, after forming electrostatic latent scratches on an electrostatic image carrier such as an electrophotographic photoreceptor,
There is a technique that visualizes this using colored powder called toner. Electrostatic images widely used in this technology
As one of our methods, the magnetic brush method is known. This magnetic brush current method has an internal Km stone and a developer supporting and conveying means such as a cylindrical sleeve on the outside.
A two-component type III agent prepared by mixing a toner with a t4-material (carrier) such as iron powder, or a one-component one-component agent containing ferromagnetic fine powder is applied. Such @image side adheres to the surface of the developer supporting and conveying means due to the attraction force, and as the developer supporting and conveying means or the internal foundation stone is rotated,
The image is transported toward an electrostatic image carrier carrying an electrostatic image.

Next, in the developing section, the developer is developed by a so-called magnetic brush formed with brush-like ears by the action of the magnetic pole inside the cartridge support and transport means.

In the above-mentioned magnetic brush shallowing method, for example, when the amount of #lis agent supplied toward the cylindrical sleeve is increased, the length of the magnetic brush increases, and the density of background fog in the developed l1iI image increases, and the magnet inside the sleeve increases. Increasing the magnetic energy causes poor reproduction of fine line images.

Furthermore, by increasing the conveyance force, the force for scraping off the toner image on the photoreceptor increases, and force scratches of 1 meter may occur in some cases.

As a method of obtaining a high-quality image with high density, high contrast, and no blurring by magnetic brush development, the method described in 'F' has been implemented, in which the image quality is improved by imparting vibration to the developing section.

(11. A method of applying a negative electric field to the developing sleeve and the acid carrier.

(21) Rotate the internal magnet to remove the external non-magnetic barrier.

J? 4 A method of moving a sleeve and an implosion magnet relative to each other.

There is. These methods agitate the developer to improve contact between the latent image area on the electrostatic image carrier and the developer, resulting in high-quality lIk.
1gI! However, it has the following drawbacks: In the method (1), several hundred to a 1
Since a bias voltage of 0,000 V is applied, dielectric breakdown is likely to occur in the electrophotographic photosensitive layer, which may easily cause problems in the durability of the photoreceptor. Moreover, it requires a power source and is not economical.

In the method (2), it is necessary to rotate the magnets in the fltm sleeve simultaneously at high speed, which results in a large mechanical load and the problem of scratching noise. Furthermore, there are limitations when trying to apply it to speed copying.

The purpose of the present invention is to obtain a high-density, smooth, and high-contrast image on an electrostatic image carrier, and also to obtain a two-component developer that is stable against fluctuations in toner density. By obtaining high contrast images, even more KI [!
The purpose is to provide a developing method that can withstand high copying speeds, and uses a method to impart oscillation to the @* area to improve image quality. By arranging the conveying means and the magnet in this order and relatively moving the agent coat supporting conveying means and the magnet, the #4 containing the magnetic material is placed on the am agent supporting conveying means.
In the electrostatic method for moving the developer, the developer supporting and conveying means is provided with a magnetic material non-uniformly;
The present invention provides an electrostatic image developing method characterized by forming a varying magnetic field at a developing position.

That is, the present invention provides appropriate magnetic fluctuations to the developer and temporarily reduces the binding force of the developer by varying the magnetic field formed by the permanent stone inside the developer supporting and conveying means. This increases the chance of the toner in the developer coming into contact with the electrostatic image on the carrier, and the chance of the toner adhering to the electrostatic image. The toner scattering effect caused by the developing brush that is formed is alleviated, thereby making it possible to obtain a 1% density and high contrast double-sided image.

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

Figure 1 shows a schematic diagram of a developing section using a magnetic fits sleeve improved according to the present invention. In Figure 97, 1 is an electrostatic image carrier such as an electrophotographic photosensitive layer or an electrostatic recording medium. It is formed on the circumferential surface of the drum and moves counterclockwise. Reference numeral 2 denotes a developing device, and when the electrostatic latent part of the electrostatic image carrier 1 comes to the position of the developing section 3 of the m-imaging device 2, a developing device having magnetic bodies 5 discontinuously disposed on the surface thereof is provided. The developer is further transported to the developer supporting and transporting means 4, and dusted by the developer 11 forming a brush in the fA section 3, where it is visualized. At this time, the magnetic body 5 discontinuously provided on the developing sleeve 4 disturbs the magnetic field formed by the fixed developing permanent magnet 6, and the rotation of the developing sleeve 4 causes the magnetic field to fluctuate. This causes agitation in the developer No. 3, which increases the replenishment of toner to the electrostatic residue area on the electrostatic carrier 1, increasing opportunities for toner contact, and ensuring that toner is sufficiently attached to the image area. A high-density image can be obtained. On the other hand, the toner scraping action is relaxed, and a high-quality image with high abrasiveness and fewer scratches caused by the magnetic brush can be obtained.

In development g3, in order to fluctuate the magnetic field formed by the permanent magnet 6 built into the developing sleeve 4, which is a developer supporting and conveying means, K is provided with a non-uniform magnetic material on the rotating viewing sleeve. It becomes possible. Next, various examples in which the magnetic material is provided non-uniformly on the VC developing sleeve will be explained.

ill A developer supporting and conveying means that contains magnetic particles in its base, which has a cylindrical base made of metal such as aluminum, stainless steel, or brass, plastic, or rubber, and contains iron, nickel, or cobalt. , containing particles of ferromagnetic material such as ferrite. Second
Figure (a) is a schematic diagram of the development sleeve, in which numeral 11 represents a base and 12 represents a magnetic material. As a manufacturing method, for example, ferrite particles and aluminum powder are melted and extruded, or nickel particles are mixed with polycarbonate (111'J) resin, pressed, and molded.

It is necessary that the magnetic material 12 is uniformly dispersed in the base Kll, and if the distribution ratio of the a-column 12 particles in the base Kll exceeds a certain limit, the fluctuation of the magnetic field will actually decrease. The magnetic particles are small pieces with a diameter of about 3 m or less, and can be molded without sticking.

Of course, you can still get the full effect even if it is still molded.

In the case of permanent magnets, if they are magnetized after molding, the fluctuations in the magnetic field will further increase. %gl in this example is extremely easy to manufacture. Father, because the surface is smooth, photosensitive method surface and dust removal support conveyance means! It is possible to obtain distance accuracy with the surface and further improve image quality.

(2) A layer containing magnetic particles is provided on the base of the developer supporting and conveying means.
Figure 2 (cl is a schematic diagram of a cross section of a developing sleeve provided with a layer containing IK spider particles within the base body. In the figure, 21 is a cylindrical shape made of metal or plastic such as aluminum, stainless steel, or brass. Basically, ?2#'i ferromagnetic particles such as iron, nickel, cobalt, ferrite, etc.
The medium is 23Fi rubber or Plasti 9 resin. As a specific manufacturing method, as shown in FIG. To make it possible to apply K, Nyackel particles ρ and conductive carbon black are mixed and dispersed in the Frethane rubber 23 and provided on the Al<x-cum substrate 21. Alternatively, an endless belt made of brass made by electroforming is used as the base 21, and after mixing and stirring nickel particles, thermosetting acrylic resin, and conductive carbon black, this is spray coated.
Therefore, it can be obtained. As is clear from the manufacturing method of this embodiment, the manufacturing method is simple, and it is suitable for use as a thin-walled developing sleeve.

(3) Magnetic particles were adhered onto the M5 plate 1 of the developer supporting and conveying means, and FIG. 2 1dl shows a schematic cross-sectional view of this developing sleeve. In the figure, 31 is a base, and 32 is a magnetic particle adhered to the surface of the base 31. For example, magnetic stainless steel powder or chromium powder is thermally sprayed onto an aluminum cylinder, and after the spraying, the periphery of the cylinder is polished. Depending on the size K of the magnetic powder to be thermally sprayed, polishing may not be necessary. By irradiating the magnetic material while rotating the cylinder at an appropriate circumferential speed, it is possible to cause the magnetic field to fluctuate at the same rate on the platform on the circumferential surface.

In this method of forming a magnetic layer on a substrate by thermal spraying, for example, by thermally spraying a mixture of magnetic stainless steel powder and non-magnetic stainless steel powder, an average magnetic layer can be effectively formed.

(4) A challenging agent supporting and conveying means having a discontinuous magnetic layer, as shown in FIGS. Magnetic floor 42
The manufacturing method is 1.For example, a thin nickel film is created all around the non-magnetic stainless steel sleeve by the electro-111 method, and then a discontinuous nickel layer in a mope-shaped or striped shape is formed by etching f&. or to form discontinuous nickel J- on the brass sleeve by electroforming. When a discontinuous magnetic layer 42 is provided on the outside of the base 41, slight unevenness occurs on the circumferential surface, but it can be made smooth by further providing a thin plastic layer on top.

(51) The developer supporting and conveying means is provided with a large number of good magnetic layers with different thicknesses, as shown in Fig. 2 (gl (hl)
lit Fi shows a schematic diagram of a cross-section of this viewing sleeve.

In the figure, 51 is a substrate, and 52 is a magnetic layer of different thickness. For example, after dispersing iron powder in natural rubber and lining it on an aluminum base, a slotting machine is used to create many grooves parallel to the sleeve axis, and then nickel powder is mixed and melted into plastic. It can be made into a cylindrical shape with a grooved layer or by extrusion molding.

This method can be easily manufactured by extrusion molding, and by providing grooves on the surface, in addition to the above-mentioned fluctuation of the magnetic field, it is possible to greatly improve the conveyance of the developer. Obtainable.

(6) The surface is magnetized to many different inertias.

The developer supporting and conveying means has a permanent magnetic layer having a magnetic layer with a magnetic body 61 as shown in FIG. For example, a permanent rubber magnet is disposed on an aluminum sleeve and magnetized discontinuously, and permanent magnet powder is dispersed in a thermosetting acrylic resin on an endless Nijikel electroformed belt. It is manufactured by applying poutine ink and discontinuously magnetizing it after drying and heat treatment.

Although various types of real NIA91 have been explained above, the above real m
It goes without saying that the present invention is not limited to this example, and that there are other similar embodiments. 1+ Although the illustrated developer supporting and conveying means are all sleeve-shaped, they may also be belt-shaped. Although the non-uniformity of the magnetic material is currently provided in the rotation direction of the sleeve, it may also be provided in the same rotation axis direction. It is preferable that the number of non-uniform pitches provided in the rotating direction of the magnetic material is at least two or more within the width of the developing section 3. When the thickness of the magnetic layer of the developer supporting and conveying means is thick, the current of the internal permanent magnet 6 is 1 mm5.
ea magnetic layer maximum thickness f13111 where the magnetic force becomes weaker
The following is desirable. The thickness of the cicada particles varies depending on how they are used in the above example, but IOpm~3
A spherical or needle-shaped material within the range of m is used.

Rounding to confirm the effect of the present invention is the following experiment 1th line (T.

Ivy.

The ms sleeve according to the present invention is produced by the following manufacturing method (Al
~(Fl (F) 6 II Terrorism 4 m 84 f
a Su') :l;' (G) II) (I) ノ38
1 is a rounded value for comparison, and this 3J* does not cause any fluctuation in the magnetic field.

(Al Aluminum powder and ferrite powder are mixed and melted and extruded (B) Nickel powder and conductive carbon black are mixed and dispersed in Fretan rubber and placed on an aluminum sleeve.

(C) Magnetic Suanless powder is sprayed onto the surface of the Fulmi sleeve and polished after spraying.

(I)l Electroforming method on stainless steel sleeve 92≠
Create a Kel film and use the etching method to create discontinuous nickel,
Forms a layer.

(A nickel layer (100p Jl) is formed discontinuously on the El k steel sleeve by electroforming.

(F) Aluminum powder and nickel powder are melted in a mixed bath and extruded into a groove shape.

(G) Sleeve with smooth surface @ Non-magnetic stainless steel powder is thermally sprayed on Arimi sleeve (Il Sleeve made of polycarbonate resin and conductive carbon black.

Konishiroku Photo Industry (closed) product u-uix30 as an experimental machine
00 was used, and the following 4 sides were used as the developer.

Two-component @ 11 agents Conductive Insulating-component magnetic toner The developing section of the above experimental machine was
b* image density is obtained, and the reflection density is 1.3.
When we conducted a development experiment with a black original of
G) ~ (Compared to the case of using a developing sleeve of Il, it is possible to obtain a high-quality image with no background blur and no blemishes at one density.Especially in the two-component visual imaging method, there is no rubbing pattern caused by the carrier.・It is extremely effective in preventing the development of S-grain, and also almost eliminates the occurrence of scratches on the photoreceptor due to copying a large number of sheets.The main experimental results are as follows.

As can be seen from the above examples, the effect of the method of the present invention is excellent in two-component visual imaging using a two-component developer gIII\IK insulating developer.

As is well known, a two-component developer consists of a carrier and a toner, but the conductive developer uses crushed and classified iron powder as a carrier.

In addition, for the insulating #44a agent, a coated carrier made of a spherical iron material covered with resin (styrene/acrylic resin) is used.

Although various resins are conventionally known as carrier materials for the insulating #4 agent, carriers tested with any of these known resins can be used in the method of the present invention.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, and FIG. 2 is a sectional view of a viewing sleeve according to the present invention.

Claims (1)

[Scope of Claims] (1) By arranging the developer supporting and conveying means on the electrostatic image carrier and the magnet in this order and moving the developer supporting and conveying means and the magnet relatively, A machine that moves the developer containing magnetic material on the developer supporting and conveying means.
4. An electrostatic image developing method, characterized in that a varying magnetic field is formed at a developing position by non-uniformly disposing a magnetic material on the #4 agent carrier carrying means. (2) The electrostatic image developing method according to claim 1, wherein the developer supporting and transporting means has a layer containing magnetic particles. (3) The electrostatic image developing method according to claim 1, characterized in that magnetic particles are adhered to the surface of the developer supporting and conveying means. (4) Electrostatic II according to Item 1 of the Patent Claim, characterized in that a developer supporting and conveying means having a discontinuous magnetic layer is provided! Block image method. (I) An electrostatic image developing method as set forth in claim 1, item 6, characterized in that a developer supporting and conveying means for holding a large number of magnetic layers having different thicknesses is provided. (6) Electrostatic image development according to claim 1, characterized in that a developer having a permanent magnet layer having a plurality of regions magnetized with different polarities on its surface, and a supporting conveyance means are provided. Method.