JPS61151552A - Method for applying toner to toner carrier - Google Patents

Abstract

PURPOSE:To apply a uniform toner thin layer to a toner carrier by combining a specific toner applying means using toner applying magnetic particles and a specific shape of magnetic particles. CONSTITUTION:Toner applying magnetic particles form a magnetic brush by the magnetic field generated between a magnet in a sleeve 3 and a magnetic blade 9. Rotation directions of two, upper and lower screws 6 and 7 are so determined that they are matched to magnetic brush flowing directions of arrows 10. If the toner exists in the area of the magnetic brush, a ratio of magnetic particles of the magnetic brush to the toner is held at an approximately certain value by the rotation of the sleeve 3. This toner shape of magnetic particles, and this shape satisfies conditions that (a), (b), and (c) of a rectangular parallelepiped circumscribed to the particle meet a>b>c, a>b=c, or a=b>c and the average value of b/a is 0.4-1.0 and that of c/a is 0.05-0.5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a toner application method for developing an electrostatic latent image formed by electrophotography using a substantially non-magnetic toner. More particularly, the present invention relates to a method of applying a substantially non-magnetic toner and magnetic particles for applying the toner in a uniform thin layer.

[Description of prior art]

As the electrophotographic method, US Pat.
Various methods are described in Japanese Patent Application Publication No. 24748, etc., but all of these methods involve applying electrostatic charge to the surface of a photoreceptor, in which a photoconductive layer is provided on a conductive layer, by means such as corona discharge, An electrostatic latent image is formed by irradiating this charged photoconductive layer with a light image corresponding to the original, and then colored fine powder called toner having a polarity opposite to that of the electrostatic latent image is applied to the electrostatic latent image. It includes the step of depositing on the electrostatic latent image and developing the latent image.

Conventionally, as a method for developing such an electrostatic latent image using toner, a uniform coating layer of toner is formed on a toner carrier,
A method is used in which when the toner layer faces the electrostatic latent image, the toner is uniformly separated from the toner carrier, transferred and attached to the latent image, and various methods and devices for this purpose have been proposed. ing. However, in any of the developing methods, it is difficult to form a uniform thin layer of toner, and for this reason, in most cases, a single relatively thick layer of toner is formed. Nowadays, there is a need to improve the sharpness and resolution of developed images, and it is essential to develop a method and apparatus for forming a uniform thin layer of toner.

A conventionally known method for forming a thin layer of toner is disclosed in Japanese Patent Application Laid-Open No. 54-43037 using a dry-component developer.
There is a method described in Japanese Patent Publications, etc., 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 the magnetic developer magnetic, a magnetic substance must be added to the toner. First, there is a problem of poor color in color electrophotography due to the internal addition of a dark-colored magnetic substance. Further, the internal addition of a magnetic material has a problem in that it has an adverse effect on the fixing performance when a developed toner image is transferred to a transfer paper such as paper and then thermally fixed, resulting in poor fixing performance.

In order to avoid these problems, various methods have been proposed in which a thin layer is formed using a non-magnetic developer (ie, non-magnetic toner). for example,? - A method of applying toner by using a cylindrical brush with soft bristles like bar hair,
There is a method of applying it 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 on the fiber brush, it is possible to control the amount of toner, but uniform application cannot be achieved, and simply rubbing the fiber brush on the developing roller cannot control the amount of toner. Since the toner present between the fibers is not sufficiently charged by frictional charging, there is a problem in that ghosts and the like are likely to occur. Furthermore, in the systems using these non-magnetic developers, it is difficult to prevent the developer from leaking from the device.

Therefore, in order to solve these problems, the present inventors have already proposed a new developing method and device for forming a magnetic brush using toner, magnetic particles for toner application, and a toner carrier. Application No. 58-151028), in the method disclosed therein, magnetic particles The amount of magnetic particles and the mixing ratio of magnetic particles and toner may be unevenly distributed or change in the longitudinal direction of the toner carrier, resulting in a difference in image quality in the longitudinal direction.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner application method that eliminates the problems of the conventional methods described above and forms a uniform thin layer of toner on the surface of a toner carrier.

Another object of the present invention is to impart sufficient triboelectric charging to the toner;
It is an object of the present invention to provide a toner application method for applying an amount of toner sufficient for development onto a toner carrier.

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

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

Still another object of the present invention is to
This is a toner application method that is further improved from the method proposed in the No. 1028 application, that is, good images can be obtained even when the copying machine is installed at an angle or after copying many originals in an area narrower than the developable area. An object of the present invention is to provide a toner application method.

[Structure of the invention]

The above objects are achieved by using the following toner application method.

That is, the present invention uses a toner and magnetic particles for toner application as a developer, a developer container for storing at least the toner and magnetic particles for toner application in a developing device, and a developer container for storing at least the toner and magnetic particles for toner application in an electrostatic latent image holder. a toner carrier for conveying the toner; a magnet for forming a magnetic brush made of toner application magnetic particles that contacts the toner carrier on the upstream side of the toner outlet of the developer container; and a circulation regulating member within the magnetic brush. and two conveyance members that alternately convey the magnetic brushes to form a thin layer of toner on the toner carrier, wherein the toner coating magnetic particles include the magnetic particles. If we imagine a rectangular parallelepiped circumscribing the rectangular parallelepiped, then define each side of the rectangular parallelepiped as a>b>c or a) b=c and 1ja=b>c, then b/ It is characterized by using magnetic particles having a shape such that the average of a is 0.4 to 1.0 and the average of c/a is 0.05 to 0.5.

The electrostatic latent image carrier used in the present invention is a drum-shaped or belt-shaped member having a photoreceptor and an insulating layer, and magnetic poles of the same or different polarity are attached in the axial direction of a magnetic roller. A magnetized one or a plurality of bar-shaped magnets glued onto a fixed support member are used. Further, as the rotating toner carrier, a sleeve made of non-magnetic metal such as aluminum, copper, stainless steel, brass, etc., a synthetic resin material, or an endless belt made of these metals or resin materials is used, and the circumferential surface thereof is The surface can be roughened or provided with an uneven pattern in order to improve toner transportability and charge imparting properties.

Furthermore, if necessary, a regulating member provided on the outlet side of the developer container may be made of magnetic material such as iron, aluminum, copper, etc.
Blade plates and walls made of non-magnetic material such as resin are used.

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

FIG. 1 is a sectional view of a developing device for explaining the phenomenon principle to which the toner application method of the present invention is applied. In the drawing, reference numeral 1 denotes an electrophotographic photosensitive drum, which holds a latent image formed by a latent image forming means (not shown) and rotates in the direction of the shown arrow. A developing sleeve 3, which is a toner carrier, faces the photosensitive drum 1 with a predetermined gap therebetween, and the sleeve 3 rotates in the direction indicated by the arrow in the figure. A fixed magnet is provided inside this sleeve 3. 2 is a developing device, 4 is a mixing part for toner and magnetic particles for toner application, 5 is a part of the toner hopper, 6 is an upper screw, 7 is a lower screw, 8 is a circulation regulation of the mixed layer of magnetic particles for toner application and toner. The member 9 represents a magnetic blade.

The mounting position of the magnet in the developing sleeve 3, which is a toner carrier, is determined by the relationship between the position of the magnetic pole and the magnetic blade 9.In reality, the magnetic pole is installed slightly upstream of the position of the magnetic blade 9. Due to the effect of the magnetic field thus formed, even better results can be obtained in terms of preventing the magnetic particles from flowing out and uniformly applying the toner.

In FIG. 2, the movement of the mixed magnetic brush of toner and toner application magnetic particles is indicated by arrows. That is, in the configuration shown in FIG. 1, the magnetic particles for toner application are generated by the magnetic field generated between the magnet inside the sleeve 3 and the magnetic blade 9, thereby forming a magnetic brush. As the sleeve 3 rotates, the toner and the toner application magnetic particles are stirred and mixed while holding the magnetic brush. In this state, on the magnetic grade 9 side, due to the presence of the circulation regulating member 8 on the blade 9, the mixture of toner and toner coating magnetic particles is prevented from moving, moves upward, and circulates in the direction of the arrow 10. As a result, the toner is triboelectrically charged by the sleeve 3 or the magnetic particles by stirring and mixing with the magnetic particles for toner application. 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 grade 9, and reaches a position facing the photoreceptor drum having an electrostatic latent image. on the other hand,
The two screws 6.7, which are conveying members, are arranged at the top and bottom, respectively, with the rotational directions as shown in FIG. ．． The feature is that they are transported alternately as shown in 12.

In Fig. 2, the upper and lower two screws are respectively placed in the magnetic brush flow direction as shown by the arrow 10 in the figure.
The rotation direction of the upper screw 6 is determined to match the respective flow directions, and after the magnetic brush lifted by the rotating sleeve 3 is pushed back by the circulation regulating member 8, it falls due to gravity. The magnetic brush is placed nearby and receives almost no force from the sleeve 3.

The lower screw 7 is provided in the vicinity where the fallen magnetic brush is attracted again to the rotating sleeve 3, and similarly the magnetic brush receives almost no force from the screw.

That is, by doing so, it is achieved that the magnetic brush is transported without being subjected to any additional force.

This agitation ability of the screws, which are the two conveying members, eliminates the tilting of the developer that may occur when the copying machine is installed at an angle, and it also eliminates the problem of inclination of the developer, which is thought to occur when the copying machine is installed at an angle. This makes it possible to eliminate defects in image quality that may occur after copying. In this case, the screw has a pitch of 2.5 to 20 mm and a screw diameter (when the shaft diameter is φ6 rts) to φ8 to 14+.
m, vertical rotation speed ratio (V top, /V bottom) 0.5 to 2.0
It is preferable that

In order to prevent the magnetic particles from flowing onto the sleeve 3, the restraining force of the magnetic particles constituting the magnetic brush due to the magnetic field of the magnet is set to be larger than the conveying force caused by the frictional force. achieved.

Further, if there is toner within the area of the magnetic brush, the ratio of the magnetic particles of the magnetic brush to the toner remains approximately constant t1 as the sleeve 3 rotates. 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, so that a constant amount of toner is always supplied and coated on the sleeve 3. .

As is clear from the above description, magnetic particles are particularly important as components in the present invention. The magnetic particles have the function of primarily imparting a charge to the toner, whereas the magnetic particles had the function of a carrier material, which was conventionally used in two-component developers by being mixed with the toner in a much larger amount than the toner. Rather than performing the function of controlling the charge t by applying the toner to the toner carrier 3, it is necessary to form a magnetic brush in a system in which a large amount of toner exists, and perform the function of controlling the amount of toner by applying the toner onto the toner carrier 3. It is something.

At the same time, the magnetic particles must also have the function of supplying toner while circulating, and furthermore, it is not preferable for the magnetic particles to pass through the regulating member 8. Furthermore, in the present invention, in order to fully utilize the effect of the two screws 6.7 for preventing inclination and deviation of the magnetic brush, it is necessary to circulate the magnetic brush in the longitudinal direction of the sleeve 3, which is the toner carrier. Appropriate control is also an important factor.

In order to fulfill these functions, the magnetic brush must have an appropriate restraining force generated by the magnetic field, and also exhibit appropriate circulation, and the brush state of the formed magnetic brush must be uniform and thin. It must have suitable hardness and density to enable layer application. For example, a relatively sparse plan tends to produce poorly defined streaks on the toner carrier, and conversely, a dense brush tends to result in an extremely thin coating layer on the toner carrier. , neither case is preferable.

Furthermore, for example, if the circulation of the magnetic brush is too good (the toner coating layer becomes thick and fogging occurs on the image), if the circulation is poor, ghosts are likely to occur, etc. In addition, from the perspective of the effectiveness of the two screws, if the circulation of the magnetic brush is too good, it will be difficult for the magnetic brush to catch on the two screws, and the magnetic brush will tilt. .

Conversely, if the circulation of the magnetic bluff is poor, the magnetic brush may not be conveyed in the longitudinal direction of the toner carrier.

As a result of examining the requirements for the magnetic particles used in the present invention to fulfill the various functions required, the present inventors have determined that the particle size, particle size distribution, and magnetic properties of the magnetic particles as well as We found that the shape has a big influence.

In other words, when the shape of the magnetic particles is close to a spherical shape, although the circulation of the formed magnetic brush is fast, the brush is too densely packed and the toner is not smoothly supplied from the hopper onto the toner carrier. Furthermore, it is difficult to stabilize the amount of magnetic brush in the longitudinal direction of the toner carrier by the magnetic brush conveying member. On the other hand, if the shape of the magnetic particles is extremely flat, the brush filling state of the formed magnetic brush will be relatively linear, and the toner will be smoothly supplied from the hopper to the toner carrier, but the magnetic Plan circulation is poor,
It is also difficult to transport the magnetic brush in the longitudinal direction of the toner carrier.

As a result of studies based on the above knowledge, it has been found that a combination of the toner application means used in the present invention with the following specific magnetic particle shapes produces good effects.

The shape of the magnetic particles for toner application in the present invention is defined as follows.

First, magnetic particles are examined using an SZ (scanning electron microscope) at an appropriate magnification.
Take photos with vC. At this time, for the same particle, take several screens in which the electron beam hits the sample stage on which the magnetic particle is perpendicular, and several screens in which it hits as horizontally as possible, and draw a rectangular parallelepiped circumscribing one particle from these.

Furthermore, each side 1a) b) c or a of this rectangular parallelepiped
) b = c or a = b) a so that c.

Set b and c and actually measure a + bHC.

Randomly perform the above operations for at least the minimum amount of particles added b/
Find the average of a and c.

In the present invention, the average b/a is 0.4 to 1.0 and c
Magnetic particles having a shape with an average of /a in the range of 0.05 to 0.5 are used, preferably /fib/a is 0.5.
~1.0, c/a is preferably in the range of 0.1 to 0.4.

Furthermore, the present inventors have found that it is preferable to control the apparent density of the magnetic particles used in order to ensure an appropriate degree of filling and appropriate softness of the magnetic brush formed. In the present invention, the apparent density of the magnetic particles is preferably 3.5f7cm3 or less. However, the measurement of apparent density is based on JIS Z 250.
The test was carried out in accordance with 4.

As the magnetic particles for toner application used in the present invention, for example, surface-oxidized or non-oxidized metals such as iron, nickel, cobalt, manganese, chromium, rare earths, and their alloys or oxides can be used. The surface may be coated with a resin or a suitable treatment agent. Moreover, there are no special restrictions on the manufacturing method.

The processing agent used to treat the surface of the magnetic particles for toner coating described above is determined depending on the toner material, the material and shape of the toner carrier, and the material and shape of the magnetic particles. Polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin,
Metal complexes of ditertiary glutyl salicylic acid, styrene resins, acrylic resins, polyamides, polyvinyl butyral, nigrosine, aminoacrylate resins, basic dyes and their lakes, silica fine powder, alumina fine powder, etc. can be used singly or in combination. Suitable, but not necessarily limiting. The total amount of these processing agents is desirably 0.1 to 30 weight/'-cent (preferably 0.5 to 20 weight percent) based on the magnetic particles of the present invention.

Next, the toner used in the present invention will be explained.

The binder resin of the toner used in the present invention includes polystyrene, monopolymers of styrene and its substituted products such as XI) p-chlorostyrene, and 4+) vinyltoluene; styrene-p-chlorostyrene copolymers, and -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, styrene-acrylic-aminoacrylic copolymer, styrene-
Aminoacrylic copolymer, styrene-α-methyl chloromethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer,
Styrene-vinylethyl ether copolymer, styrene-
Styrenic compounds such as vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-imprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer Copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, chilled 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 a colorant in the toner. For example, there are known facial cleansers such as carbon black, iron black, phthalocyanine blue, gunse, quinacridone, and benzidine yellow.

In addition, as a charge control agent, amine compounds, quaternary ammonium compounds, organic dyes, especially basic dyes and their salts,
Benzyldimethyl-hexadecyl ammonium chloride, derutrimethylammonium chloride, nigrosine base, nigrosine hydrochloride, safranin γ and crystal violet, alloy metal dyes, salicylic acid-containing metal compounds, and the like may be added.

Furthermore, magnetic powder may be added to an extent that does not impede the effects of the present invention.

The toner structure described above may be used in a developer produced by a commonly used mixing-pulverization method, or may be used as a wall material or a core material, or both, of a microcapsule developer.

〔Example〕

Hereinafter, the present invention will be explained in more detail according to Examples 1 to 3, but the present invention is not limited thereto. All parts shown in each example are parts by weight. Also,
In each example, a developing device shown in FIG. 1 was used.

The apparatus used will be described in more detail below.

That is, the photosensitive drum 1 is rotated in the direction of the arrow at a circumferential speed of 100 cm/sec, and the toner carrier 3 is a sleeve made of stainless steel (SUS304) with an outer diameter of 20 mm and a thickness of 0.8 mm. The surface is subjected to irregular sandblasting using +600 Alundum abrasive grains, and the roughness of the circumferential surface is reduced to 0.
．． Using 8 μm, 100wn in the direction of the arrow.
It was rotated at a circumferential speed of /sec. A sintered ferrite type magnet is fixedly arranged inside the rotating sleeve 3, and the first
The north pole of the magnetic pole was set with respect to the magnetic blade 9 by varying the angle from the line connecting the center of the sleeve 3 and the tip of the magnetic blade. The magnetic blade 9 was made of iron, the surface of which was plated with nickel to prevent rust, and was set at an interval of 200 μm from the surface of the sleeve 30. Also, each screw 6.7 has a pitch diameter of 1)01E% 1
A 5M1rs screw with a screw diameter of 10 mm and a weight of 12 g (shaft diameter of 6 mm) was used, and the rotation ratio of the upper and lower screws was set to 1.

Example 1 The above materials were mixed, melted and kneaded, cooled, pulverized and classified to obtain particles with an average particle size of 12 μm. To 100 parts of these particles, 0.5 part of colloidal silica was added externally to form a toner. .

On the other hand, as magnetic particles for toner application, b/a=0.8
, c/a = 0.2, apparent density 2.8 t/crn
Iron powder having a particle size of 150 to 200 mesh was prepared.

After 10 parts of the above toner and the toner coating magnetic particle blade were thoroughly mixed, they were placed in the mixing section 4 of the developing device. Next, put 200 parts of toner into the hopper 5 of the developing device, and add it little by little.
The stirring device was adjusted so that it was added above the mixing section 4.

The mixture of toner and toner-applying magnetic particles in the mixing section 4 is produced in particular by the fact that the magnetic particles are conveyed by the sleeve 3 under a magnetic field and by the two screws 6.7 in the longitudinal direction of the sleeve. It was observed that the particles were transported, indicating good circulatory movement. As the sleeve 3 of the developing device rotated, a uniform thin layer made only of toner was formed on the surface of the sleeve.

On the surface of the photosensitive drum 1 facing the sleeve 3, an electrostatic latent image with a charge pattern of 600V in the dark and -150V in the light was formed, and the distance 'i from the sleeve surface was set to 300 μm. When a voltage with a frequency of 800V and a peak-to-peak value of 1.4KV and a center value of -300V was applied to the above sleeve using power supply E, high quality was obtained without uneven development, ghost images, and fog. A clear blue developed image could be obtained, and this state continued until the toner ran 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, only the toner was consumed for development, with almost no magnetic particles being consumed.

Further, the developing function remained stable until almost all of the toner was consumed. After the developer was consumed, I took out the developing device from the main body and looked at the lower part of the sleeve 2, and found that not only were there no magnetic particles, but almost no toner had leaked there.

Furthermore, when copying was performed with the entire apparatus tilted, the magnetic brush did not become biased and good images continued to be produced.

Comparative Example 1 As magnetic particles for toner application, b/a=0.7, c/a
=0.6, apparent density is 3.8 f 7cm3, particle size is 15
The same procedure as in Example 1 was carried out except that iron powder having a mesh size between 0 and 200 was used.

As a result, the brushes of the magnetic brushes formed were too densely packed, resulting in poor image density.

Furthermore, by tilting the entire apparatus by just 2° C., the magnetic brush was biased downward, causing unevenness in image density in the longitudinal direction of the sleeve.

Comparative Example 2 As magnetic particles for toner application, b/a=0.3c/a=
0.03, apparent density 2.217m3, particle size 150~2
The same procedure as in Example 1 was carried out except that iron powder having a mesh size of 0.00 to 0.00 was used.

As a result, the movement of the formed magnetic brush was extremely poor, the state of toner application on the sleeve was extremely uneven, and it was difficult to stabilize the magnetic brush in the longitudinal direction of the sleeve using the screw.

Example 2 As magnetic particles for toner application, b/a=0.9, c/a
= 0.15, apparent density 2.5 f/cm', grain size 15
The same procedure as in Example 1 was performed except that iron powder having a mesh size of 0 to 200 was used, and the same good results as in Example 1 were obtained.

Example 3 The above materials were mixed, melt-kneaded, crushed, and classified to obtain an average particle size of 1.
) μ particles were obtained, and 0.6 part of colloidal silica was externally added to 100 parts of the particles to prepare a toner.

On the other hand, as magnetic particles for toner application, b/a=0.6,
c/a=0.4, apparent density 3.497cm3, particle size -
For 100 parts of iron powder between 150 and 200 mesh,
Is the surface coated with a portion of silicone resin?
Using.

This toner and magnetic particles for toner application were put into a developing device in the same manner as in Example 1, and an electrostatic latent image was formed on the photoreceptor drum with a dark area of +500 V and a bright area of 1100 V, a frequency of 1300 Hz for the sleeve, and peak-to-peak. The value is 1.4KV,
Development was carried out in the same manner as in Example 1 except that a voltage with a center value of +200 V was applied, and the same good results as in Example 1 were obtained.

[Summary of effects of the invention]

According to the present invention, by combining a specific toner coating means using magnetic particles for toner coating and a specific shape of the magnetic particles as described above, a uniform thin layer of toner is coated on a toner carrier. As a result, a developed Raya Ghost image and a fog-free, high-quality, clear copy image can be obtained, and the good image lasts until the toner runs out. Further, the magnetic PIE particles for toner application are prevented from flowing onto the sleeve, and the magnetic particles are hardly consumed during development, and development can be continued only by replenishing toner. Furthermore, according to the present invention, even when the copying machine is installed tilted, it is possible to obtain copies of excellent images.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts of a developing device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the state of developer conveyance in the developing device of FIG. 1, and FIG. It is a perspective view showing the movement of developer near the screw. 1... Photosensitive drum 2... Developing device 3... Developing sleeve 4... Mixing section 5 for toner and magnetic particles for toner application.
・Toner hot spots 6... Upper screw 7... Lower screw 8... Circulation regulating member 9... Magnetic blade 10, 1), 12... Mixture of toner and magnetic particles for toner application In other words, the arrows indicate the movement of the magnetic brush.

Claims (2)

[Claims] (1) A developer container that stores at least toner and magnetic particles for toner application in a developing device, a toner carrier that conveys the toner to an electrostatic charge holder, and the developer container (a).
a magnet forming a magnetic brush made of toner coating magnetic particles that contacts the toner carrier (b) on the upstream side of the toner outlet; a circulation regulating member and a magnetic brush that are alternately conveyed within the magnetic brush; In the toner application method in which a thin layer of toner is formed on the toner carrier by arranging a book conveying member, when the magnetic particles are assumed to be rectangular parallelepipeds circumscribing the magnetic particles, each side of the rectangular parallelepiped is a>b
>c or a>b=c or a=b>c, then a
, b, and c, the average of b/a is 0.4 to 1.
0 and an average c/a of 0.05 to 0.5. (2) The toner coating method according to claim 1, wherein the apparent density of the magnetic particles is 3.5 g/cm^3 or less.