JPS61186973A - Toner applying method - Google Patents

Abstract

PURPOSE:To form a uniform thin layer by providing a circulation control member of a magnetic brush, and two carrying members for carrying alternately the magnetic brush, in a system in which the magnetic brush executes a circulating movement, and using that which has performed a specified treatment, as a toner applying use magnetic particle. CONSTITUTION:A circulating control member of a magnetic brush and two carrying members for carrying alternately the magnetic brush are provided in a system in which the magnetic brush executes a circulating movement, and a thin layer of a toner is formed on a toner carrying body. A treatment for satisfying the expression is performed to a toner applying use magnetic particle. In this way, a uniform thin layer of a toner can be formed on the toner carrying body, and a clear color image of a high quality, which is free from an uneven development, a ghost image and a fog is obtained.

Description

Detailed Description of the Invention [Technical Field to which the Invention Pertains] The present invention relates to a toner application method for developing an electrostatic latent image formed by electrophotography using a substantially non-magnetic toner. Regarding. More particularly, the present invention relates to a method of forming a uniform thin layer of a substantially non-magnetic toner and magnetic toner particles.

[Description of prior art]

For electrophotography, U.S. Patent No. 2, 297.691
Specification, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 4
Various methods are described in Publication No. 3-24748, etc., but all of these methods apply electrostatic charge to the surface of a photoreceptor having a photoconductive layer by means such as corona discharge, A photoconductive layer is irradiated with a light image corresponding to the original to completely form an electrostatic latent image, and then colored fine powder called toner having the opposite polarity is deposited on the electrostatic latent image. After developing the electrostatic latent image and transferring the entire toner image to a transfer material such as paper if necessary, it is fixed by heat, pressure, solvent vapor, etc. to obtain a copy.

The process of developing the electrostatic latent image involves attracting toner particles charged with a polarity opposite to that of the latent image by electrostatic attraction and making them adhere to the electrostatic latent image. Methods for developing images using toner can be roughly divided into:
There is a method using a so-called two-component developer in which a small amount of toner is dispersed in a medium called a carrier, and a method using a so-called one-component developer in which the toner is used alone without using a carrier.

Methods using two-component developers charge the toner and carrier with different polarities by stirring and friction, and include the cascade method using glass peas and kumquats as the carrier, and the magnetic brush method using iron powder as the carrier. etc. In either case, the toner in the developer maintains its charged state during the development process and is gradually consumed during image formation, so if the toner content falls below the optimum content, the image density will decrease and the image will become faint and faded. In addition, the carrier may adhere to the photoreceptor or the shallow grooves of the paper, causing various defects. In addition, if an excessive amount of toner is contained, the amount of toner adhesion increases and the image density increases; In addition, electrostatic repulsion between excess toner particles tends to cause scattering and contamination inside the device.Therefore, it is necessary to replenish toner during development to maintain the content in the developer within a certain range. be.

In order to eliminate these problems with two-component developers, development methods using various one-component developers have been proposed and put into practical use. However, in either method, it is difficult to form a uniform thin layer of toner using a -component developer, and therefore a relatively thick layer of toner is often formed. Nowadays, there is a need to improve the clarity and resolution of developed images, and there is an urgent need to develop a method and apparatus for forming a uniform thin layer of toner.

As a conventionally known method for forming a thin layer of toner, there is a method described in JP-A-54-43037 using a -component developer, and this method has also been put into practical use. . This method uses a magnetic developer (so-called magnetic toner) as a developer and forms a thin layer with a magnetic brush, but in order to make magnetic toner magnetic, a magnetic substance must be added to the toner. .

Magnetic materials generally have a black or blackish-brown color, so
If a submagnetic toner is used with this internally added, it is difficult to obtain a clear color image, and this causes the problem of poor color in color electrophotography. Further, the internal addition of a magnetic substance has a problem in that it has an adverse effect on the fixing performance when the toner image after development is transferred onto a transfer paper and is thermally fixed, resulting in insufficient fixing performance.

In order to avoid these problems, various methods have been proposed in which a thin layer is formed using nonmagnetic toner. for example,
A cylindrical brush made of soft bristles like beaver hair,
There are methods such as applying the toner by adhering it to the toner, and applying the toner to a developing roller whose surface is made of fibers such as velvet using a doctor blade or the like. However, when an elastic blade is used as a doctor blade in the fiber brush,
Although it is possible to regulate the amount of toner, uniform application is difficult.
Simply rubbing the fiber brush on the developing roller does not sufficiently charge the toner existing between the fibers of the brush by frictional charging, which poses a problem in that ghosts and the like are likely to occur. Furthermore, in systems using these non-magnetic toners, it is difficult to prevent developer from leaking from the device.

The present inventor has previously proposed a new toner coating method and apparatus using magnetic particles for toner coating, which solves the problems of the conventional methods described above (Japanese Patent Application No. 58-151028, etc.) The invention of the prior application is a toner application method in which substantially non-magnetic toner and magnetic particles for toner application are used all around the area, and in detail, at least the toner and the magnetic particles for toner application are stored in the developing device. a toner carrier that conveys toner to a latent image carrier, and a magnet that forms a magnetic brush made of toner application magnetic particles that contacts the toner carrier on an upstream side of a toner outlet of the developer container. and a toner coating method and apparatus for forming a thin layer of toner on the toner carrier.

However, in the toner application method disclosed in the above-mentioned Japanese Patent Application No. 151,028/1984, it is difficult to make multiple copies when the copying device is installed tilted for a long time, or when a document with an area narrower than the developable area is used. In such cases, differences in image quality may occur in the longitudinal direction of the toner carrier during subsequent copying. This occurs because the amount of toner coating magnetic particles, the mixing ratio of toner coating magnetic particles and toner, etc. are unevenly distributed or changed in the longitudinal direction of the toner carrier.

[Purpose of the invention]

The main object of the present invention is to provide a novel toner coating method that overcomes the problems of the toner coating method using the above-mentioned substantially non-magnetic toner and toner coating magnetic particles. .

Another object of the present invention is to provide a toner application method in which toner is formed as a uniform thin layer on a toner carrier.

Still another object of the present invention is to provide a method for imparting sufficient triboelectric charging to toner and applying a sufficient but not excessive amount of toner for development onto a toner carrier.

Still another object of the present invention is to obtain a good developed image that does not cause problems such as capri and a decrease in image density.

Another object of the present invention is to provide a longitudinal direction of the toner carrier during subsequent copying, such as when a copying machine is installed tilted for a long time or when a large number of copies are made using an original with an area narrower than the developable area. The goal is to prevent differences in image quality.

Yet another object of the present invention is to obtain sharp color images using substantially non-magnetic toner.

Another object of the present invention is to prevent developer from leaking out of the developing device.

[Structure of the invention]

The above-mentioned object of the present invention is to alternately convey the circulation regulating member of the magnetic brush and the magnetic brush in the system in which the magnetic brush of the above-mentioned toner application method disclosed in Japanese Patent Application No. 58-151028 etc. circulates. This is achieved by further arranging two conveyance members and using specially treated magnetic particles for toner application.

That is, the toner application method of the present invention includes at least a developer container for storing toner and toner application magnetic particles in a developing device, a toner carrier for conveying the toner to a latent image carrier, and the developer container. A magnet forming a magnetic brush made of toner application magnetic particles that contacts the toner carrier on the upstream side of the toner outlet, and a circulation regulating member of the magnetic brush and a magnetic brush arranged alternately in a system in which the magnetic brush circulates. two conveying members are disposed to form a thin layer of toner on the toner carrier, and the magnetic particles for toner application are subjected to a treatment satisfying the following formula (I) e. This toner application method is characterized in that:

0.01≦′1/,≦0.7・・・・・・・・・(I)
(However, % iI represents the current value of the magnetic particles for toner application before processing, and 12 represents the current value of the magnetic particles for toner application after processing.) As the latent image carrier used in the present invention, the photoreceptor It is a drum-shaped or belt-shaped member with an insulating layer, and the magnetic pole is a magnet roller with magnetic poles of the same or different polarity magnetized in the axial direction, or a plurality of rod-shaped magnets fixedly supported. It can be used that is glued onto a member. Furthermore, as the rotating toner carrier, it is possible to use a sleeve made of a non-magnetic metal such as aluminum, copper, stainless steel, or brass, or a synthetic resin material, or an endless belt made of resin or metal. Alternatively, a roughened surface or an uneven pattern may be provided to improve charging characteristics. Further, as the circulation regulating member used in the present invention, a blade plate or wall made of a magnetic material such as iron or a non-magnetic material such as aluminum, copper, or resin may be used, and as the conveying member, a screw conveyor may be used.

The coating method of the present invention will be specifically described below using an example of a developing device to which the coating method of the present invention can be applied.

Figure 1 is a cross-sectional view of one example of the developing device, and Figure 2 is a cross-sectional view of one example of the developing device.
FIG. 3 is a diagram for explaining the movement of the magnetic brush when the developing device shown in the figure is used, and FIG. FIG.

In FIG. 1, 1 is a photosensitive main drum which is a latent image holder.
It holds a latent image formed by a latent image forming means (not shown), and rotates in the direction of arrow a and passes through the development position shown. A non-magnetic sleeve 3, which is a toner carrier carrying toner, faces the photosensitive drum 1 with a predetermined gap therebetween, and the sleeve 3 rotates in the direction indicated by the arrow. At the top of this sleeve 3, there is a toner hopper part 5 made of non-magnetic material such as resin or aluminum, and a developer container 2 having a mixing part 4 for toner and toner application magnetic particles below the toner hopper part 5. located this container 2
A magnetic blade 9 and a circulation regulating member 8 are installed downstream in the rotational direction of the sleeve, and screw conveyors 6.7, which are two conveying members for alternately conveying the magnetic brushes, are disposed within the mixing section 4.

On the other hand, a magnet carrier (not shown) is provided inside the sleeve 3. The mounting position of the magnet in the sleeve is determined by the relationship between the position of the magnetic pole and the magnetic blade 9, but it is preferable to provide the magnetic pole slightly upstream of the position of the magnetic blade 9. Due to the action of the magnetic field thus formed, the magnetic particles for toner application are transferred to the magnetic blade 9 and the circulation regulating member 8.
Even better results can be obtained in terms of the effect of preventing the toner from flowing out onto the sleeve 3 through the toner and the effect of forming a uniform thin layer of toner on the sleeve 3.

Next, using FIG. 2, what is the principle of the toner application method of the present invention? explain. Arrow 10 in FIG. 2 indicates the movement of a magnetic brush containing a mixture of toner application magnetic particles and toner.

In the present invention, in the above configuration, the toner applying magnetic particles form a magnetic brush due to the magnetic field generated between the magnet inside the sleeve and the magnetic blade 9. and,
As the sleeve 3 rotates, the magnetic particles for applying toner are mixed with the toner while being formed on the magnetic brush. In this state, on the magnetic blade 9 side, due to the presence of the magnetic blade 9 and the above-mentioned circulation regulating member 8, the movement of the mixture of toner application magnetic particles and toner is prevented, and the movement of the mixture of the toner coating magnetic particles and toner is prevented. circular motion in the direction. The toner in the mixing section 4 is triboelectrically charged by the sleeve 3 or the toner coating magnetic particles while the toner is mixed with the toner coating magnetic particles and circulated. The charged toner is uniformly and thinly applied to the surface of the sleeve 3 by mirror force by a magnetic brush formed near the magnetic blade 9, and reaches a position facing the photoreceptor drum 1.

On the other hand, the magnetic particles for toner application that make up the magnetic brush are
By setting the restraining force due to the magnetic field of the magnet inside the sleeve to be stronger than the conveying force caused by frictional force, it is prevented from flowing out onto the sleeve 3 through the magnetic blade 9. If there is toner within the area of the magnetic brush, the ratio of the toner of the magnetic brush to the magnetic particles for applying toner is maintained at a substantially constant value by the rotation of the sleeve 3. As a result, even if the toner on the sleeve 3 is consumed during development, the toner is automatically supplied to the area of the magnetic brush, making it possible to always supply a constant amount of toner onto the sleeve 3.

The screw conveyors 6, 7, which are the conveying members for the magnetic brushes in the present invention, are arranged above and below the mixing section 4, in which the magnetic brushes circulate, with rotational directions as shown in FIG. It plays the role of alternately conveying magnetic brushes containing a mixture of magnetic particles and toner as shown by arrows 11 and 12.

As shown in FIG. 2, in the present invention, the above-mentioned two upper and lower screw conveyors are each rotated in the direction of rotation.
The magnetic brush is installed so as to match the flow direction of the magnetic brush indicated by the arrow 10 shown in the figure. The upper screw conveyor 6 is installed near the position where the magnetic brush lifted by the rotating sleeve 3 is pushed back by the circulation regulating member 8 and then falls by gravity. The magnetic brush near 6 is sleeve 3
It receives almost no force from Further, the lower screw conveyor 7 is provided near the position where the falling magnetic brush is attracted again to the rotating sleeve 3, and similarly, the magnetic brush near the screw conveyor 7 is not affected by the force from the upper screw conveyor 6. I hardly get it. With this configuration, it is achieved that the magnetic brush is transported without being subjected to additional forces. The two screw conveyors use their agitation ability to prevent the developer from being generated when the copying machine is tilted or when a large number of copies are made using an original that is narrower than the developable area. It is possible to eliminate inclination and bias, and to solve the problem of poor image quality that often occurs in subsequent copying in these cases. In the present invention, the pitch, diameter, and upper and lower rotational speed ratios of the screws of the screw conveyor are respectively adjusted to a pitch of 2.5 to 20, a screw diameter (when the shaft diameter is 966 mm), a diameter of 8 to V, a height of 14, Preferable results can be obtained by setting the vertical rotation ratio (/) in the range of 0.5 to 2.0.

As is clear from the above description of the coating method of the present invention, the function of the toner coating magnetic particles used in the toner coating method of the present invention is important in order to achieve all the objects of the present invention. That is, the magnetic particles for toner application used in the present invention form a magnetic brush in a system where a large amount of toner is present, and do not pass through a magnetic blade, but can be applied while having an appropriate restraining force generated by a magnetic field. It has many functions such as supplying a predetermined amount of toner onto the toner carrier and supplying toner while circulating in the system, as well as charging the toner by smoothly circulating it in the system. must be maintained. Furthermore, in order to fully exhibit the effect of the screw conveyor 6.7, which is the two conveying members provided to prevent the inclination and deviation bt of the magnetic brush in the present invention, it is necessary to use the magnetic brush for toner application used in the present invention. The particles must have the ability to properly control the entire circulation of the magnetic brush in the longitudinal direction of the sleeve 3.

That is, in order to have these functions, the magnetic brush formed of the magnetic particles for toner application must have an appropriate restraining force generated by the magnetic field and appropriate circulation. must be used selectively. Also,
In order to enable uniform toner application, it is necessary to select and use toner application magnetic particles such that the magnetic brush formed by the toner application magnetic particles has appropriate hardness and density. For example, if the formed magnetic brush is a comparative fishing line, it will prevent uncontrolled streaks from forming on the toner carrier, and conversely, if the formed magnetic brush is relatively dense, it will prevent the formation of uncontrolled streaks on the toner carrier. The thickness of the layer is made very thin, and in both cases, favorable results are not obtained.

In addition, if the circulation of the formed magnetic brush is too good, the coated layer may become thicker, causing capri on the image.
The magnetic brush gets caught in the screw conveyor of books, and the screw conveyor's effect of preventing the magnetic brush from tilting or shifting is not fully demonstrated. Furthermore, if the formed magnetic brush has poor circulation, ghosts are likely to appear on the image, or the magnetic brush may not be conveyed in the longitudinal direction of the toner carrier.

The electrical properties of the magnetic particles for toner coating are
The experimental results of the present inventors have revealed the fact that the magnetic field of the magnetic brush formed by the above-mentioned magnetic particles for applying toner has a large effect on the binding force and circulation, and on the density and density of the formed magnetic plan. .

In other words, when the current value of the magnetic particles for toner application used is very large, the charge of the toner tends to leak and the formed magnetic brush becomes relatively linear, so that the toner is smoothly supplied from the hopper to the toner carrier. However, the circulation of the magnetic brush becomes poor, making it difficult to convey the magnetic brush in the longitudinal direction of the toner carrier. On the other hand, if the current value of the magnetic particles for toner application used is very small, the toner charge will not easily leak, and the magnetic brush formed will be too dense, causing the toner to be supplied from the hopper to the toner carrier. Moreover, even if a magnetic brush conveying member is used, the amount of magnetic brush in the longitudinal direction of the toner carrier is not stabilized sufficiently.

Based on the above findings, we investigated the current value of the magnetic particles for toner coating used in the present invention in order to fulfill the required functions, and found that the magnetic particles for toner coating are processed to have a specific current value. It has become clear that the object of the present invention can be achieved by doing so.

That is, the magnetic particles for toner application have the following formula (I)
It has been processed to satisfy e.

0.01≦4≦0.7 (I) (where s il represents the current value of the magnetic particles for toner application before treatment, and 12 represents the current value of the magnetic particles for toner application after treatment. The method for measuring the current value of magnetic particles for toner application in the present invention will be described in detail with reference to the drawings.

FIG. 4 is an explanatory diagram of a device used in the present invention for measuring a current value using a magnetic brush. In the figure, 14 represents a developing box, and inside the developing box 14 is a sleeve 1 having a magnetic brush made of magnetic particles for applying toner.
5 and the aluminum drum 16, the distance between them is 4.
．． It will be set up so that there will be five cabinets. First, as shown in FIG. 4, a resistor of IMΩ, a resistor of IOKΩ, and a developing box 14 filled with magnetic particles 13 are arranged in series.

Next, while rotating the sleeve 15, apply a DC 200Vk load, and read the voltage drop across the 10Ω resistance. From this voltage value, determine the current value flowing through the main circuit using the following calculation.

Measurement example: Voltage drop 100XIOV (V=IR)
100 x 10 V= I x 10 x 1
031 = 1o x 10' (A) However, the measurement conditions are 23°C and 60% RH.

As the magnetic particles for toner application before treatment used in the present invention, known magnetic particles can be used as long as their surfaces are not treated with organic or inorganic substances.

Examples include surface-oxidized or unoxidized metals such as iron, nickel, cobalt, manganese, chromium, rare earths, and alloys or oxides thereof. However, the present invention is not limited to these, and other materials may also be used.

Friend, there are no particular restrictions on the method for producing the magnetic particles for toner application before treatment used in the present invention.

In addition, as a method for treating magnetic particles for toner coating that satisfies the above conditions, a resin, a facial cleanser, a charge control agent, a fluidity control agent, etc. may be applied singly or in combination to the surface of the magnetic particles for toner coating before treatment. (Hereinafter referred to as "treatment agent.") A method of fixation is adopted. The fixing method is to mix the processing agent in a powder state with the magnetic particles for toner application, heat it to melt or soften the processing agent, and then fix it to the magnetic particles for toner application, or to dissolve or suspend the processing agent in a solvent. Conventionally known methods include a method in which the processing agent is made cloudy and then applied to the magnetic particles for toner application and then fixed thereon, or a method in which the processing agent is simply mixed in powder form with the magnetic particles for toner application and the processing agent is fixed to the magnetic particles for toner application. Both are applicable.

The substance that adheres to the surface of the magnetic particles used in the present invention varies depending on the toner material used in the present invention, but examples include polytetrafluoroethylene, monochlorotrifluoroethylene combination, polyvinylidene fluoride-silicone resin, polyester resin t-ditarsia, etc. A metal complex of ligtylsalicylic acid, styrene resin to acrylic resin, jellyamide, polypynylphtyral to nigrosine A aminoacrylate resin, 1 basic dye and its lake, 1 fine silica powder, 1 fine alumina powder, etc. are used singly or in combination. is suitable, but is not necessarily limited to this.

The amount of the above-mentioned compound to be treated may be appropriately determined so that the magnetic particles satisfy the above conditions, but in general, the total amount is 0.1 to 30% by weight (preferably 0.5 to 20% by weight) based on the magnetic particles of the present invention. weight i percent) is desirable.

The toner used in the present invention contains at least a binder resin and a colorant, and examples of the binder resin in the toner used in the present invention include styrene such as polystyrene, polyp-chlorostyrene, and polyvinyltoluene. Substituted homopolymers; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene -Ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer Polymer, styrene-acrylic-aminoacrylic copolymer, styrene-aminoacrylic copolymer, styrene-alpha chloromethyl methacrylate copolymer, styrene/-
Acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinylethyl ether copolymer, styrene-vinyl methyl keto y copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile -indene copolymer,
Styrenic copolymers such as styrene-maleic acid copolymers and styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, Epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin,
Chlorinated paraffin, paraffin wax, etc. can be used alone or in combination.

Any suitable pigment or dye can be used as the colorant for the toner used in the present invention. For example, carbon black, iron black, phthalocyanine blue, ultramarine, quinacridone,
There are known dyes and pigments such as Pe/Jijin Yeku.

The toner used in the present invention also contains an amine compound, a quaternary ammonium compound, an organic dye, and a charge control agent.
In particular, basic dyes and their salts, benzyldimethyl-hexadecyl ammonium chloride, decyl-trimethylammonium chloride, nigrosine base, nigrosine hydrochloride, safranin γ and crystal violet, metal-containing dyes, salicylic acid-containing compounds, etc. may be added. . Furthermore, magnetic powder may be added to an extent that does not impede the effects of the present invention.

The toner used in the present invention may be a toner produced by a commonly used mixing-pulverization method, or a toner in the form of microcapsules.

〔Example〕

The present invention will be explained in more detail below using Example 1.2 and Comparative Examples 1 to 3. The parts given in the examples are parts by weight.

On each side, the developing apparatus of FIG. 1 was used.

In FIG. 1, the photosensitive drum 1 is moved 100 mm in the direction of the arrow.
It rotates at a circumferential speed of 1+Il+I/sec. 3 is a group with an outer diameter of 20.1 that rotates at a circumferential speed of 100 mm/sec in the direction of arrow 6,
The sleeve is made of stainless steel (SUS 30.4) with a thickness of 0.8 mm, and its surface is subjected to amorphous sandblasting '2 using Alundum abrasive grains of ≠600, and the roughness of the circumferential surface is 0.8 μm. (Rz = ).

On the other hand, a sintered ferrite type magnet is completely fixed inside the rotating sleeve 3, and the N pole of the first magnetic pole is connected to the magnetic blade 9 from a line connecting the center O of the sleeve 3 and the tip of the blade. It is set at a 30 degree angle.

The magnetic blade 9 is made of iron, and its surface is nickel plated to prevent rust. This blade 9 was set at a distance 'i of 200 μm from the surface of the sleeve 3.

Further, the screw conveyor 6.7, which is a conveying member, has pitches of 10 pitches and 15 pitches, screw diameters of 10 pitches and 12 mm (shaft diameter 6 mm), and an upper and lower rotation ratio of 1.

A mixture of Example 1 was kneaded and melted, cooled, and then classified to obtain particles with an average particle size of 12 μm. 0.5% by weight of colloidal silica was externally added to the particles to prepare a toner.

On the other hand, thermosetting acrylic resin was adhered to amorphous iron powder having an average particle size of about 75 to 100 microns at the ratios shown in Table 1, and then treated. When the current values before and after the treatment of the iron powder were measured, the magnetic particles B1C and D as shown in Table 1 below satisfied the conditions of formula (I).

Table 1 After thoroughly mixing 10 parts by weight of the above toner and 50 parts by weight of magnetic particles for toner coating using magnetic particles B in Table 1, the mixture is placed in the mixing section 4 of the developing device shown in FIG. Next, toner-20
Put the 0M amount into the toner hopper 5, and add it little by little to the mixing part 4.
A stirrer was set up to add on top. The mixture of the toner and the magnetic particles for toner application in the mixing section 4 is particularly characterized by the fact that the magnetic particles for toner application slip and slide under a magnetic field.
and two screws 6.7.
It was clearly observed that the material was transported in the longitudinal direction.

In the developing device having the above configuration, a thin layer made only of toner could be formed on the surface of the sleeve 3 as the sleeve rotated 30 times. On the surface of the photosensitive drum 1 facing the sleeve 3, a charge pattern of +600 V in the dark part and +150 V in the bright part was formed as an electrostatic latent image, and the distance from the sleeve surface was set to 300 μm. When a voltage with a frequency of 800 Hz, a peak-to-peak value of 1.4 KV, and a center value of +300 cm was applied to the sleeve using power source E, a high-quality clear image was obtained with no uneven development, no ghost images, and no fogging. A blue developed image can be obtained, and this state will continue until the toner runs out.

In addition, good images were obtained even under special environments of high temperature and high humidity, and low temperature and low humidity.

Further, regarding the mixture in the mixing section 4, the magnetic particles for toner application were hardly consumed, and only the toner was consumed for the purpose of development. Further, the developing function remained stable until most of the toner was consumed. After consuming the above developer, remove the developing device from the main body and remove the sleeve 2.
When I looked at the bottom of the toner, not only were there magnetic particles for toner application, but there was almost no leakage of toner.

I also tried copying with the entire device tilted by 5 degrees, but the magnetic brush did not become biased and good images continued to be produced. Furthermore,
The same procedure as in the case of using the magnetic particles B in Table 1 except that the magnetic particles C and Dt in Table 1 were used resulted in the same good results as in the case of using the magnetic particles Bt as the magnetic particles for toner application. This was the result.

Comparative Example 1 The same procedure as in the case of using the magnetic particles B in Table 1 except that the magnetic particles Af in Table 1 were used as the magnetic particles for toner application, the movement of the magnetic brush was extremely poor, and the movement of the magnetic brush to the sleeve 3 was The state of toner application was extremely uneven, and the magnetic brush could not be stabilized in the longitudinal direction of the sleeve 3 by the screws 6 and 7.

In addition, when the same procedure was used as when magnetic particles B in Table 1 were used except that two of the magnetic particles E in Table 1 were used as the magnetic particles for toner application, the magnetic brush was too densely clogged, resulting in poor image density. It became thinner. Further, when the entire apparatus was tilted by only 2 degrees, the magnetic brush was biased downward, causing uneven image density in the longitudinal direction of the sleeve.

A toner was prepared in the same manner as in Example 1 except that the mixture of Example 2 was used.

On the other hand, butyl acrylate-styrene copolymer was fixed to the same amorphous iron powder as in Example] at the ratios shown in Table 2, and the treated syllables were prepared. When the current values before and after the treatment of the iron powder were measured, the results were as shown in Table 2 below, and the magnetic particles G and H1■ satisfied all the conditions of formula (I).

Table 2 Magnetic particles G%H11 in Table 2 as magnetic particles for toner application
When image formation was carried out in the same manner as in Example 1 using each of i, the results were similar to those in Example 1 when magnetic particles B, C, D'& of Table 1 were used as magnetic particles for toner application. The results were good.

Comparative Example 2 Image formation was performed in the same manner as in Example 1 except that the magnetic particles Fft shown in Table 2 were used as the magnetic particles for toner application, but the movement of the magnetic brush was extremely poor and the state of toner application on the sleeve was poor. There was severe unevenness, and stabilization of the brush in the longitudinal direction of the sleeve by the screw was not achieved.

In addition, magnetic particles J in Table 2 are used as magnetic particles for toner coating.
When images were produced in the same manner as in Example 1 except for the holes used in E, the magnetic brushes were too densely clogged, resulting in poor image density. Furthermore, when the entire apparatus was tilted by just 2 degrees, the magnetic brush was biased downward, causing uneven image density in the longitudinal direction of the sleeve.

[Summary of effects of the invention]

According to the present invention, as described above, a specific toner application means is combined with specific toner application magnetic particles, that is, toner application magnetic particles treated so that the ratio of the current value before and after the treatment is within a specific range. By using this method, it is possible to form a uniform thin layer of toner on the toner carrier, thereby making it possible to obtain high-quality, clear color images without uneven development, ghost images, or capri. , the good image lasts until the toner runs out. Further, in the present invention, since the toner coating magnetic particles are prevented from flowing onto the sleeve, the toner coating magnetic particles are hardly consumed, and development can be continued only by replenishing toner.

Further, according to the present invention, when the copying machine is installed tilted for a long time or when making multiple copies using an original in an area narrower than the developing area, the longitudinal direction of the toner carrier is There is no difference in image quality between the

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an example of a developing device used to carry out the coating method of the present invention, FIG. 2 is a diagram illustrating the movement of the magnetic brush when the developing device of FIG. 1 is used, and FIG. FIG. 4 is a perspective view showing the movement of the circulation regulating member of the present invention, the screw conveyor which is the conveying member, and the magnetic brush caused by these, and is a diagram for explaining the method of measuring the current value of magnetic particles of the present invention. In the figure, 1 is a photoreceptor drum, 2 is a developer container, 3 is a rotating sleeve, 4 is a mixing section for toner coating magnetic particles and toner, 5 is toner, 6 is an upper screw conveyor, and 7 is a lower screw conveyor. , 8 indicates a circulation regulating member, 9 indicates a magnetic blade, arrows 10 to 12 indicate movement of the magnetic brush, 13 indicates a magnetic brush formed of magnetic particles for applying toner, 14 indicates an aluminum drum, and 5 indicates a sleeve. Figure 2

Claims (1)

[Scope of Claims] A developing device includes at least a developer container that stores toner and magnetic particles for toner application, a toner carrier that conveys the toner to a latent image carrier, and a toner outlet of the developer container. A magnet forming a magnetic brush made of toner applying magnetic particles that contacts the toner carrier on the upstream side, and two magnets that alternately convey a magnetic brush circulation regulating member and the magnetic brush within a system in which the magnetic brush circulates. A conveying member is arranged,
A toner coating method for forming a thin layer of toner on the toner carrier, wherein the toner coating magnetic particles are subjected to a treatment satisfying the following formula (I). Method. 0.01≦i_2/i_1≦…………(I) (However,
i_1 represents the current value of the toner application magnetic particles before treatment, and i_2 represents the current value of the toner application magnetic particles after treatment. )