JPS61130962A - Developing method - Google Patents

Abstract

PURPOSE:To obtain an image having high fidelity by disposing an electrostatic image holding body which holds an electrostatic latent image on the surface and a toner carrying body apart at a specified space from each other and using a non-magnetic toner having prescribed characteristics to execute development. CONSTITUTION:The cylindrical electrostatic image holding body 1 is formed thereon with the electrostatic latent image by, for example, a Carlson method which is a known electrophotographic method and is developed by a toner 5 coated by a coating means 4 which coats the insulating toner 5 in a toner supplying means, i.e., a hopper 3 on the toner carrying body 2 by controlling the thickness of the toner layer. The body 1 which holds the electrostatic image on the surface and the body 2 which carries the toner on the surface are dis posed apart at the specified space from each other in the developing part. The substantially non-magnetic toner having 10-20mu volume average grain size in which 5.04-2.02mu of the volume distribution is >=50% and having >=1.2 true specific gravity is used as the toner. The development is executed by depositing such toner on the body 2 to the thickness smaller than the space between the body 2 and the body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for developing an electrostatic latent image formed on the surface of a latent image carrier, particularly a method for developing a thin and uniform layer of insulating toner on a toner carrier. It is related to.

Conventionally, the following methods are known as developing methods using -component non-magnetic or weakly magnetic toners.

For example, in an electrostatic image development method in which an electrostatic image on the surface of a latent image holder is developed by placing developer carriers holding developer on their surfaces facing each other, the developer is stored in a developer storage means. When the developer under the developer carrier is pumped up onto the developer carrier, vibration is applied to the developer in the pumped-up portion to activate it, and a predetermined thickness of developer is deposited on the surface of the developer carrier. There is a development method in which a layer is formed and then developed.

Also, a rotatable magnetic roller that adsorbs a magnetic carrier for charging the -component non-magnetic toner particles to form a magnetic brush, and a rotatable magnetic roller that transfers the toner particles of the roller, p,!
It has a developing roller for developing the electrostatic image on the electrostatic image holder, and maintains a gap between the electrostatic image holder and the developing roller in the developing section, and the gap length is equal to the toner coating layer on the developing roller. There is a method of developing an electrostatic image by increasing the thickness of the image.

The movable developer carrying means carries and conveys the developer and supplies it to the latent image holder, the developer replenishing means, and the movable developer carrying means receives the developer from the developer replenishing means. A movable application means for applying the developer is used to carry the developer on the surface #l! The above-mentioned movable coating means has a fiber brush, and moves at high speed in the same direction as the movable developer carrying means at the abutting portion by contacting the movable developer carrying means. There is a method in which the toner is uniformly applied to the surface of the movable developer carrying means and the applied layer is brought close to the electrostatic latent image area.

Compared to conventional developing methods using one-component toner, these methods require a lot of pressure when applying the toner to the toner carrier, so the amount of triboelectric charge on the toner tends to be high, and the development time is short. At the same time, the amount of triboelectric charge increases, and as a result, the image density of the resulting copy changes over time, resulting in the problem that the quality of the copy cannot be kept constant.

In addition, these methods are methods in which insulating non-magnetic or weakly magnetic toner is supported on a carrier mainly by non-magnetic force in the developing section and developed. Electrostatic attraction and physical adhesion are the dominant forces that cause the toner to be supported on the carrier, and in contrast, conventional insulating magnetic materials that support the toner on the carrier by magnetic force, electrostatic force, etc. Various problems arise compared to developing methods using toner. For example, a phenomenon occurs that many toners are not applied relatively thinly and uniformly on the carrier.

Furthermore, for example, relatively uniformly! Even if the toner is covered with a cloth, toner adheres to the non-image area, resulting in so-called soil blurring. Furthermore, even if the toner is applied thinly and uniformly, the amount of toner adhering to the image area is insufficient, resulting in an image with low density. Sara<
Many toners, even when applied thinly and evenly, can produce very poor images with low fidelity and low resolution. Additionally, many toners can be used repeatedly and over time, resulting in decreased image density and poor quality images. In addition, toners with high performance have the problem that they sometimes cause a decrease in image density when exposed to environmental changes such as high temperatures, high temperatures, low temperatures and low humidity, and other times cause blurring. Ta.

Furthermore, since the toner cannot be restrained by magnetic force, the toner often scatters, spills, etc. and contaminates the imager and the device.

In addition, a developing method using a component magnetic toner (because the magnetic toner particles contain a large amount of magnetic powder)
This is not expensive compared to non-magnetic or weakly magnetic toners, and it has been difficult to produce beautiful colors.

An object of the present invention is to provide a new developing method using an insulating non-magnetic or weakly magnetic toner that eliminates the above-mentioned problems. That is, an object of the present invention is to provide a current method with high fidelity and stable image quality. A further objective is to provide a developing method that eliminates the blurring phenomenon and provides a uniform and high-resolution image in the image area in just one shot.

Another object of the present invention is to provide a developing method using an insulating non-magnetic toner that has excellent durability such as delayed use characteristics.

Another object of the present invention is to provide a developing method using an insulating nonmagnetic toner that is stable against environmental changes such as high temperature and high humidity, and low temperature and low humidity.

Another object of the present invention is to provide a developing method that provides an image with sharp hues.

A further object of the present invention is to provide a developing method with extremely low toner scattering and spillage. , the toner is placed on the surface (the toner carrying member is placed with a certain gap in the developing section, and the volume average particle diameter is 10 to 2 μm), and the volume distribution is 5.04 to 2.
0.2 μm is 50% or more and the true specific gravity of the roll is 1.2) A large, substantially non-magnetic toner is supported on the toner carrier to a thin thickness in the gap, and the toner is pressed into the developing section button. The present invention provides a developing method in which the electrostatic image carrier is transferred to the electrostatic image holder and developed.

In the developing method of the present invention, if necessary, an alternating current and/or
Alternatively, it is preferable to apply a DC bias.

The inventors of the present invention have investigated various developing methods using conventionally known non-magnetic or weakly magnetic toners, and found that in order to solve the above-mentioned problems, compared to developing methods using magnetic toners, We have discovered that it is important to precisely control the amount of electrostatic charge and fluidity of the toner on the toner carrier in the developing section. For example, if the amount of charge is low, a phenomenon occurs in which the toner is not evenly applied on the toner carrier, and uniform 1C development is not possible, and even if the charge t is increased to create a condition where the 1C is evenly applied, the value is not appropriate. delk
(If the value is too high, the electrostatic attraction between the toner carrier and the toner carrier is too strong, making it difficult for the toner to transfer to the electrostatic image carrier. , resulting in a decrease in image density and the appearance of low-quality images.

In addition, if the fluidity is poor, uniform coating is required, and even if uniform coating is achieved, smooth development will not be possible. Therefore, in order to uniformly apply a non-magnetic or weakly magnetic toner onto a toner carrier in a state where sufficient development is possible, it is necessary to precisely control the amount of electrostatic charge and fluidity of the toner. They concluded that it is necessary to appropriately adjust the particle size distribution of the toner. It goes without saying that, in general, the amount of electrostatic charge and fluidity of a toner largely depend on its particle size distribution.

In addition, in order to prevent toner from scattering and spilling, the particle size distribution is properly controlled and a relatively heavy toner is used.The present invention uses a relatively heavy toner that is non-magnetic or weakly magnetic, and is applied mainly to non-magnetic forces in the developing section. The above-mentioned requirements due to the method of supporting and developing the toner on a wedge carrier are achieved by adjusting the particle size distribution of the toner.

In the present invention, weak magnetism means that an external magnetic field of 500
It refers to a state that can be considered to be substantially non-magnetic, with a saturation magnetization + Oemu/q or less.

The non-magnetic or weakly magnetic toner having the particle size distribution of the present invention was uniformly coated on the carrier and showed good development even by various coating methods as described below. Furthermore, this remained unchanged even under high temperature and high humidity environments, low temperature and low humidity environments, and after long-term image production.

Furthermore, toner scattering and spillage are almost eliminated, and the image device is no longer stained.

The particle size distribution of the toner can be measured using a generally commercially available particle size distribution measuring device, such as a particle size distribution analyzer (Particle Data Co., Ltd.), a Viatsuk automatic particle size distribution analyzer (Biatsuku Royco Co., Ltd.), and a laser granulometer (C
Engineering LAS), Micro Trunk (LEIDS &
N0RTHI (UP), Micron Photosizer (
Seishin Enterprise), Luzex (Japan Regulator), Fu! It can be measured using any equipment such as a letter counter (Coulter Electronics).

As the binder resin for the toner, monopolymers of styrene and its substituted products such as polystyrene, poly p-chlorostyrene, and polyvinyltoluene; styrene-p-chlorostyrene copolymers, styrene-propylene copolymers, and styrene-p-chlorostyrene copolymers are used.
Vinifretoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-acrylic ethyl copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer , styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene/-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene- Vinyl methyl ether copolymer, styrene-vinylethyl ether copolymer, styrene/-vinyl methyl ketone copolymer, styrene/-butadiene copolymer, styrene-isobre/copolymer, styrene μy-7 cyclonitrile Styrenic copolymers such as indene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer; polymethyl methacrylate,
Polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane/polyamide, epoxy resin, polyvinyl butyl, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic Or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin,
Paraffin wax and the like can be used alone or in combination.

As the coloring material used in the toner, conventionally known carbon black, dye, pigment, etc. can be used.
+ means a negative charge control agent can be used in the present invention.

In order to make the toner supplementally retain magnetism, magnetic powder may be included. Such magnetic powder is a substance that is magnetized when placed in a magnetic field, and includes powders of ferromagnetic metals such as iron, cobalt, and nickel, and alloys and compounds such as magnetite, hemartite, and ferrite. The content of this magnetic powder is preferably 15% by weight or less based on the weight of the toner.

The toner is optionally mixed with carrier particles such as iron powder, glass beads, nickel powder, ferrite powder, etc.
Used as a developer for electrical latent images.

The toner used in the present invention may be produced by any method, for example, by kneading, pulverizing, and classifying as known in the art, or by dispersing it in a liquid phase or gas phase and granulating it. Things, etc. Alternatively, it may be microencapsulated.

) Hereinafter, the present invention will be explained in detail based on embodiment examples using the drawings.

FIG. 1 shows an example of an embodiment of an electrostatic latent image developing method and a developing device using an insulating toner. In the figure, reference numeral 1 denotes a cylindrical electrostatic image holder, on which an electrostatic latent image is formed by, for example, a known electrophotographic method such as the Carlson method or the NP method. The toner 5 is developed by applying the toner 5 onto the toner carrier 2 by controlling the thickness of each toner layer. The toner carrier 2 is a cylindrical developing roller 2 made of stainless steel.
It is. The developing roller may be made of aluminum or other metals. Alternatively, a metal roller coated with resin or the like may be used in order to frictionally charge the toner to a desired polarity. Additionally, the developer roller may be made of an electrically conductive non-metallic material. Although the ends of the toner carrier 2 are not shown, spacer rollers made of high-density polyethylene are inserted into the shaft thereof.

By abutting this spacer roller on both sides 1'A K of the electrostatic image carrier 1 and fixing the developing device, the electrostatic image carrier 1
The distance between the toner carrier 2 and the toner carrier 2 is set and maintained to be greater than the thickness of one layer of toner applied on the toner carrier 2. This interval is for example 100μ to sooμ, preferably +soμ to 3o
It is oμ. If this distance is too large, the electrostatic force exerted by the electrostatic latent image on the image carrier 1 on the non-magnetic toner coated on the toner carrier 2 will be weak, and the image quality will deteriorate, especially for fine lines. Visualization by development becomes difficult. If the distance between the toner and the electrostatic image carrier 1 is too large, there is a high risk that the toner applied on the toner carrier 2 will be compressed and aggregated between the toner carrier 2 and the electrostatic image carrier 1. , 6 is a developing bias power source, which can apply a voltage between the toner carrier 2 and the back electrode of the electrostatic image carrier 1. This developing bias voltage is a developing bias voltage as described in Japanese Patent Publication No. 58-32375.

FIG. 2 is a diagram showing another example of the embodiment.

In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier,
5 is toner, 3 is hopper, 9 is cleaning blade,
10 indicates a toner supply member.

16 is a photographing member, 17 is a photographing generating means, 16a is a permanent magnet, +61) is a support spring, 17a is an iron core, and +7'b is a winding. Winding 171) By applying K alternating current, the vibration member 16
is vibrated with an appropriate amplitude and number of images to form a uniform toner coating layer on the toner carrier 2 rotating at a constant speed, and the toner carrier 2 and the electrostatic image holder 1 are separated from each other in the toner coating layer. The non-magnetic toner is caused to fly onto the electrostatic image and developed by maintaining a gap larger than the thickness. The vibration of the vibrating member 16 may be at any level as long as it does not come into direct contact with the toner carrier 2, but it is better to control the frequency and amplitude so that the toner coating layer has a uniform thickness of about 5 to 100 μm. Furthermore, it is also possible to apply an AC and/or DC developing bias voltage between the toner carrier 2 and the electrostatic image holder 1.

FIG. 3 is a diagram showing another example of the embodiment.

In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, and 3 is a toner carrier.
5 is a developing container, 5 is a toner, 6 is a developing bias power source, 9 is a toner cleaning member, 35 is a coating roller, 56 is a fiber brush fixed to the surface thereof, and 40 is a coating bias power source.

The toner 5 is uniformly applied onto the toner carrier 2 by rotating the application roller 35 and conveyed by the brush 36, and is caused to fly onto the electrostatic image on the electrostatic image holder 1 for development. One gap between the toner carrier 2 and the application roller 55 is 5 to
Adjustments may be made to form a uniform toner layer of about 100 μm, and a bias voltage may be applied by a coating bias power source 40 for uniform toner application. The gap may be made larger than the thickness of the toner, and a developing bias (from the developing bias power source 6) may be applied when the developing button is pressed.

Diagram M4 is a diagram showing another example of the embodiment.

In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, and 5 is a toner carrier.
49 is the toner, 45 is the developer container, and 4B is the magnetic roller.
50 is a magnet, 52 is a magnetic brush, and 53 is a one-component toner or a two-component developer in which toner and magnetic particles are mixed. Magnetic particles are held on the non-magnetic sleeve 49 by magnetic force to form a brush, and the non-magnetic sleeve 49
By rotating the developer 53, the developer 53 is drawn up by the carrier brush and applied onto the toner carrier 2 in contact with the developer 53, thereby forming a uniform toner layer 5. At this time, since the carrier is held on the magnetic roller 48 by magnetic force, it does not move onto the toner carrier 2.

Next, the toner is developed by flying from the toner carrier 2 onto the electrostatic image holder 1. The gap between the magnetic roller 48 and the toner carrier 20 is adjusted so that the thickness of one layer of toner on the toner carrier 2 is about 5 to 100 μm. The gap between the toner carrier 2 and the electrostatic image holder 1 may be made larger than the thickness of the toner, and a developing bias voltage may be applied to the toner carrier 2.

FIG. 5 is a diagram showing still another example of the embodiment. In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, 3 is a hopper, 6 is an fA image M bias power supply, 51't, )ner, 5o is a fixed magnet, 52 is a magnetic particle, and magnetism due to the toner mixture Brush, 5th shows a toner-4 regulating blade.

The magnetic brush 52 formed with VC is formed on the toner carrier 2 by rotating the toner carrier 2 to form a ring, and the hopper 3
The toner inside is poured in and coated in a uniform thin layer on the toner carrier 2. The toner carrier 2 and the electrostatic image carrier 1 are placed in opposition with a larger gap than the thickness of the toner, and the one-component non-magnetic toner on the toner carrier 2 and =5 are placed on the electrostatic charge image on the electrostatic image carrier 1. Let's develop the image. The charge amount and thickness of the toner layer are controlled by the size of the magnetic pusher 52, the degree of circulation of the brush, etc. 6. The gap between the electrostatic image carrier 1 and the toner carrier 2 is set to be larger than the toner layer thickness. .

A developing bias may be applied to the developing bias power supply 6.

FIG. 6 is a diagram showing still another example of the embodiment of the present invention. In Figure 6, 1 is a cylindrical electrophotographic photoreceptor)
Move in the direction of arrow a. A non-magnetic sleeve 2, which is a toner carrier, is provided with a gap between the photoreceptor IK and the photoreceptor IK. This sleeve 2 rotates in the direction of the arrow as the photoreceptor 1 moves. A fixed magnet 50 is provided within the sleeve 2 as a magnetic field generating means. Reference numeral 3 denotes a hopper serving as a developer supply container, which accommodates a developer mixture containing toner 5 and magnetic particles 60 together with the sleeve 2.

A magnetic brush made of magnetic particles 60 is formed near the surface of the sleeve 2 corresponding to the magnetic pole 621C of the magnet 50. When the sleeve 2 is rotated in the direction indicated by the arrow, by appropriately selecting the arrangement position of the magnetic pole 62 and the fluidity and magnetic properties of the magnetic particles 60, the magnetic brush circulates in the direction of the arrow C near the magnetic pole 62. Form layer 66.

On the other hand, the magnetic pole 62) also has a point 68 on the downstream side in the rotational direction of the sleeve.
At the position shown in FIG.
The sleeve 2 is tilted downstream in the direction of sleeve movement with an angle δ formed between the normal line n of the sleeve 2 at position 8 and the center line l of the blade. The magnetic particles 60 are restrained at a point 68 on the surface of the sleeve 2 due to a balance between the restraining force based on gravity, magnetic force, and the effect of the presence of the magnetic blade 64 and the conveying force in the direction of movement of the sleeve 2, and are restrained at a point 68 on the surface of the sleeve 2, and do not move to some extent. A stationary layer 65 is formed which is obtained but is almost immobile. This circulation layer 66
A magnetic particle layer consisting of a static IfI65 and a stationary IfI65 is a sleeve 20.
formed on the surface. The magnetic particle layer contains toner 5'5r), and the magnetic particles of the stationary layer 65 are restrained on the sleeve surface by the balance between the restraining force and the conveying force described above, but the toner is substantially non-magnetic. When the sleeve is rounded, it is not restrained by the magnetic field of the magnetic pole 62, and is uniformly and thinly coated on the sleeve surface by the mirroring force, and is conveyed as the sleeve rotates and is exposed to the surface of the photoreceptor 10 for development.

In the circulation layer 66, the magnetic brush circulates as shown by arrow C due to the magnetic force and friction force due to gravity and magnetic poles, and the fluidity (viscosity) K of the magnetic particles. The toner 5 is taken in from the developer layer 67 and returned to the lower part of the hopper 3, and this cycle is repeated thereafter.The magnetic blade 64 is not directly involved in this cycle.

The developing method used here is Special Publication No. 5-3257
The method described in 5 is preferred. A bias power supply 6 is connected between the electrophotographic photoreceptor 1 and the toner carrier 2! :, D voltage is applied. The bias power supply 6 may be alternating current or direct current, but
It is preferable to superimpose direct current on alternating current. The developer supplied (for development) is supplied to the toner carrier 2 from the circulating layer 66, and the shortage in the circulating layer 66 is compensated for by the above-mentioned product term motion.
It is supplied from developer M67.

〔Example〕

After thoroughly mixing the above materials in a blender, they were kneaded with two rolls heated to 150 υ. After allowing the mixed material to cool naturally, it is coarsely pulverized with a cutter mill, then pulverized with a jet air flow using a nine-fine pulverizer, and further classified using a wind classifier. After death, colloidal silica is 0.3% by weight When added externally, the volume average particle size is 12.8 μm, and 5.04 to 20.2 μm is 8
A toner of 5% was obtained (measurement was carried out using a Coulter Counter τA-IK manufactured by Coulter Electronics Co., Ltd. The same applies to the following examples). The true specific gravity is 1.24.

On the other hand, a mixture consisting of 100 parts by weight of zinc oxide, 20 parts by weight of styrene-butadiene copolymer, 40 parts by weight of n-butyl methacrylate, 120 parts by weight of toluene, and 4 parts by weight of Rose Bengal 1-thimethanol solution was dispersed in a ball mill for 6 hours. Mixed. This was applied to a 0.05 m thick aluminum plate with a dry coating thickness of 40 μm using a wire bar, the solvent was evaporated with hot air, a zinc oxide binder type photoreceptor was produced, and the film was bound in a drum shape.

This photoreceptor was subjected to corona discharge of 1 cm and 6 kV to uniformly charge the entire surface, and then an original image was irradiated to form an n-electronic latent image.

When the toner was put into a developing device as shown in FIG. 1, a uniform coating was obtained, and the electrostatic latent image formed above was developed. In this case, the toner carrier 2 is outside fi.
A 50B stainless steel cylindrical sleeve was used, and the distance between the photosensitive drum surface and the sleeve surface was set to 00251IjlIVC, and the sleeve was connected to an AC of 400Hz + 0OOV and -+
50 Vf) DC bias was applied.

Next, the powder bond was transferred while irradiating the back side of the transfer paper with a direct current corona of 5-7 kV to obtain a copied image.

For fixing, use a commercially available plain paper copying machine (product name: NP-saao
, manufactured by Canon].

The resulting pale blue transferred image had a sufficiently high density of 1.21, no fogging, no toner scattering around the image, and was a good image with high resolution. Durability was continuously tested using the above-mentioned toner, and the transferred images after 9 too many sheets were found to be completely dull in color compared to the initial images.

When the environmental conditions are 35 and 85%, the image density is 1.20, which is almost the same as normal temperature and humidity, and a clear color image with no fogging or scattering is obtained. There was almost no change in durability up to 10,000 sheets. Next! c.
When I obtained a transferred image using the 10-inch low temperature and low humidity button, the image density was as high as 1.27, and solid black areas were developed and transferred extremely smoothly, resulting in an excellent image with no splatters or hollow spots. . Durability tests were conducted under these environmental conditions in continuous and -listening modes, and the density fluctuation was ±0.2 up to 10,000 sheets, which was sufficient for practical use. Furthermore, there was almost no toner scattering or spillage.

[Comparative Example 1] The pulverization conditions and classification conditions of the toner of Example 1 were changed so that the volume average particle diameter was 8 μm, and 48% was 5.04 to 20.2 μm. When this was applied onto the holder in the same manner as in Example 1, the coating was uniform but rather thick, and good development was not possible. Also, since there are many fine toners,
There was a lot of toner scattering.

[Comparative Example 2] The toner of Example 1 was prepared by changing the pulverization conditions and classification conditions so that the volume average particle diameter was 23 μm and 36% was 5.04 to 20.2 μm. This was done in the same manner as in Example 1, and the V
C@ When I applied it to a cloth, I was unable to apply it uniformly, and even after developing it, I was only able to obtain an image with a lot of fog. Also, there was a lot of toner spilling from the developing device.

[Example 2] The toner of Example 1 was put into the apparatus shown in FIG. 2, and the vibrating member 16 was vibrated at a frequency of 50 Hz and a vibration rate of 0.2.
When the toner carrier 2 is rotated at a circumferential speed of 120 B/ssc, a uniform toner coating layer with a thickness of about 50 μm is formed on the toner carrier, and the toner carrier 2 and the electrostatic image holder 1 are rotated at a circumferential speed of about 30 μm.
Maximum surface potential -6007 when facing each other with a gap of μ
Toner carrier 21C frequency 100~
Several kilometers H2, minus peak value -660 to -1200V
Similar good results were obtained by applying a bias alternating current electric field with a plus peak value of +400 to +8007.

On the other hand, when the toners of Comparative Examples 1 and 2 were developed as described above, the defects described in Comparative Examples 1 and 2 were noticeable.

[Example 3] Consisting of volume average 17.3 μm, 5.04 to 20
．． A toner with 58% 2 μm was obtained. True specific gravity was 1.30.

This toner 7 is put into the developing device shown in FIG. 5, in which the gap between the toner holder 2 and the application roller 350 is set to about 2 mm, and the length of the fiber brush 36 is set to about 3 mm. Keeping the gap at 300μ, a single layer of toner of approximately 50μ is formed on the developing roller, and an AC waveform is applied at a frequency of 20μ.
0H2 voltage peak value ±450v and DC component 250Vt
- In addition, similar good results were obtained when a peak voltage of +700v and -200v was applied and development was carried out using a Canon NP-200J photoreceptor.

[Example 4] The toner 2Of of Example 3 had a particle size of 2ao-so.

The mixture is mixed with the ferrite particles 40f between the meshes and placed in the developing device shown in FIG. 4, which is set so that the gap between the toner carrier 2 and the magnetic roller 48 is approximately 2 waL, and the maximum density of the magnetic brush 52 is 311iE. When developed in the same manner as in Example 3, similar good results were obtained.

[Example 5] The toner 20F of Example 1 was mixed in advance with iron powder 20f having a particle size of 150 to 300 mesh, and the mixture was mixed so that the gap between the regulating blade 58 and the toner carrier 2 was about 250 μ. When the sample was placed in the developing device shown in FIG. 5 and developed in the same manner as in Example 1, the same good results were obtained.

[Example 6] 20 ft of toner of Example 1 - Particle size 150-250 in advance
Mixed with iron powder 501F between meshes, regulating blade 6
When the sample was placed in the developing device shown in FIG. 6, which was set so that the gap between the toner carrier 4 and the toner carrier 2 was approximately 300 μm, and development was carried out in the same manner as in Example 1, similar good results were obtained.

[Brief explanation of drawings]

No figure 1! FIG. 6 is a sectional view showing a developing method according to the present invention and a developing device of a different form used for carrying out the method. DESCRIPTION OF SYMBOLS 1... Electrostatic image holding member 2... Toner carrying member 3... Hotsuno f-4... Toner application means 5... -component non-magnetic toner 6... Development bias power supply 9... Toner cleaning grade 10...Toner supply member 16...Photographing member 17...Photographing generating means
) 55... Application roller 56... Fiber brush 40... Bias power supply for application 4 days... Magnetic roller 49... Non-magnetic sleeve 50... Permanent magnet 52... Magnetic brush 55... -Non-component non-magnetic toner or a mixture of it and magnetic particles 92-component developer 58...Regulation blade

Claims (1)

[Claims] An electrostatic image carrier that holds an electrostatic image on its surface and a toner carrier that carries toner on its surface are arranged with a certain gap in the developing section, and have a volume average particle diameter of 10 to 20 μm and a volumetric A toner having a distribution of 5.04 to 20.2 μm of 50% or more, a true specific gravity greater than 1.2, and substantially non-magnetic is supported on a toner carrier to a thickness thinner than the gap. . A developing method, characterized in that the toner is transferred to the electrostatic image holder in a developing section and developed.