JP2541935B2 - Image forming method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an image forming method for forming a brush with a small amount of magnetic particles on a toner holding member using a dry developer and supplying the brush for development.

[Conventional technology]

Conventionally, various methods have been proposed and put into practical use as a dry developing method. For example, in a developing method using a two-component developer, when the image portion of the latent image is developed by the developer applied on the developing roller, the toner in the developer contains the toner of the developer applied on the developing roller. Of these, less than a few percent are used. This is extremely inefficient considering the developing device configuration. This is because it is necessary to apply a large amount of developer on the developing roller with a constant amount and uniform toner concentration each time the developing roller rotates in order to obtain a predetermined sufficient developing concentration. For this reason, the structure of the developing device has become large and complicated. Of course, in this type of developing system, attempts have been made to improve the developing efficiency. For example, JP-A-55-32060 and JP-A-55-133058.
In JP-A-56-70560, a useful developing method is proposed and put to practical use.

According to this, the development density can be increased and the development efficiency can be improved, but almost 100% in the image area.
However, this type of developing method has room for improvement. In terms of improving development efficiency, 1
The component development method is superior to the two component development method.
Among them, particularly in the developing method described in JP-A-54-43037, a toner thin layer having a thickness of 200 μm or less is formed on the developing roller, and the toner applied on the sleeve is almost always present in the image area.
The development efficiency is close to 100%. For this reason, the developing device has been put into practical use while being downsized and simplified.

This was achieved because a thin layer of 200 μm or less could be formed on the developing roller. However, it is extremely difficult to form a thin layer of the dry developer in any of the developing methods, and the developing device is configured by forming a relatively thick layer in the one-component development for this purpose. However, from the viewpoint of image quality, nowadays, it is required to improve the sharpness and resolution of a developed image, and it is essential to develop a method and apparatus for forming a thin layer of a dry developer.

However, the above method relates to the formation of a thin layer of magnetic toner. In order to impart magnetic properties to magnetic toner, it is necessary to internally add a magnetic substance to the toner. This is because of poor fixability when thermally fixing a developed image transferred onto transfer paper, and the magnetic substance is internally added to the toner itself. In order to do so (the magnetic substance is usually black), there is a problem such as poor color when reproducing the color.

For this reason, as a method for forming a thin layer of non-magnetic toner, a method in which soft bristles such as beaver's bristles are made into a cylindrical brush and toner is adhered and applied thereto, or a developing roller whose surface is made of fiber such as velvet is used. There has been proposed a method of coating with a doctor blade or the like.

However, when an elastic blade is used as a doctor blade in the fiber brush, it is possible to regulate the amount of toner, or uniform application is not performed, and the fiber of the brush is simply rubbed by rubbing the fiber brush on the developing roller. Since triboelectrification charges are not applied to the toner existing between them, there is a problem that fogging or the like is likely to occur.

Further, magnetic toners can easily prevent toner scattering by utilizing magnetic force, but non-magnetic toners cannot utilize magnetic force and toners are easily scattered inside the machine. The inconveniences described above occur not only during copying, but also when vibration or shock is applied during transportation of the apparatus.

The applicant of the present application uses a non-magnetic toner and magnetic particles as a developing device which is completely different from the above-mentioned conventional method, provides a magnetic particle restraining member facing the toner carrying member, and restrains the magnetic particle with respect to the moving direction of the surface of the holding member. A method has been proposed in which a magnetic brush of magnetic particles is formed upstream of the member by the magnetic force of the magnetic field generating means, the magnetic brush is restricted by the magnetic particle restriction member, and a thin layer of nonmagnetic toner is formed on the toner holding member. (See JP-A-58-143360) By this method,
A method of obtaining a non-magnetic toner developed image on the surface of the latent image carrier by setting an interval between the latent image carrier and the toner carrier in the developing member to be wider than the toner layer thickness and applying an alternating electric field has been put into practical use. As a result, it is possible to obtain a color developed image with a developing device having a very small developing efficiency and a very simple developing efficiency. In particular, a rubbing mark generated in a solid image portion during rubbing development with a two-component magnetic brush was bad, and a good quality solid image was obtained. However, further improvement in development image quality,
For example, it has been desired to develop a developing method that further improves gradation.

The present invention has been made in view of the above-mentioned conventional circumstances, and an object thereof is to provide a compact and lightweight color developing system which has a very high developing efficiency and can obtain a developed image which is not inferior to the conventional developing system. .

Another object of the present invention is to provide a clear color image forming method which is free from fluctuations in image density and fog even after repeated use.

Another object of the present invention is to provide a highly durable color image forming method which does not damage the surface of the photoconductor even for an OPC photoreceptor having a relatively soft surface.

That is, according to the present invention, an alternating electric field is provided between the latent image carrier and the latent image carrier for holding the electrostatic latent image and the developing region of the developer carrier opposite to the latent image carrier. In an image forming method of developing an electrostatic latent image with a non-magnetic toner containing at least a binder resin and a pigment while applying the non-magnetic toner, the non-magnetic toner is mixed with the general formula before being mixed with the binder resin. (1) (In the formula, R ₁ , R ₂ and R ₃ each represent a hydrogen atom, a substituted or unsubstituted hydrocarbon group, and n represents an integer of 1 or more. Provided that R ₁ and R ₂ are simultaneously hydrogen atoms. It contains an organic pigment or a surfactant treated with a polymer synthesized from a monomer represented by the formula (1) and an organic pigment treated with the polymer, and has a true specific gravity of 6 g / cm ³ or less, In addition, by using magnetic particles coated with an electrically insulating resin, a developing area of the developer carrier, a magnetic brush is formed so that the amount of the magnetic particles present is 5 to 100 mg / cm ^2, and And developing the latent image while reciprocating non-magnetic toner between the latent image holder and the surface of the developer bearing member and the surface of the magnetic brush while bringing the latent image holder and the magnetic brush into contact with each other. Image forming method.

The hydrocarbon group is preferably an alkyl group, an aryl group or an aralkyl group. Further, R ₁ and R ₂ may be a group which together forms an alkylene group and is bonded to an N atom to form a ring.

The substituted or unsubstituted hydrocarbon group is preferably a group having 1 to 10 carbon atoms. In particular, R ₃ is a hydrogen atom,
It is preferably a methyl group or an ethyl group, and R ₁ , R
₂ is preferably a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a cyclohexyl group or a phenyl group.

The polymer may be not only a homopolymer of the monomer represented by the general formula (1) but also a copolymer of the monomer represented by the general formula (1) and a monomer or a polymer copolymerizable therewith. .

As a result of earnest studies on the improvement of the developing method disclosed in Japanese Patent Laid-Open No. 58-143360, the inventors of the present invention formed a clear developing magnetic pole in the developing section to carry out locally concentrated development, and one-component system development. In the method, since the triboelectrification is imparted to the toner mainly between the sleeve surface,
By substantially increasing the sleeve surface area, it is possible to stabilize the triboelectricity of the toner, stabilize the toner supply on the sleeve, and improve the image quality such as gradation and uniformity. I found it. Further, the flight development from the toner carrying pair and the magnetic particles, which are the features of the main development method used in the present invention, are smoothly performed.
It has been found that an extremely vivid color image can be stably formed even after repeated development for a long period of time.

That is, in the main developing method, a good image can be obtained without providing a complicated stirring mechanism of toner and magnetic particles and a precise toner concentration control mechanism like the conventional two-component magnetic brush developing, It is necessary to utilize the surfaces of both the toner carrier and the magnetic particles forming the magnetic brush to take in the toner, perform triboelectrification, and sequentially perform flight development. A non-magnetic toner containing an organic pigment treated with a polymer synthesized from a monomer represented by the general formula (1) used in the present invention or a surfactant and the organic pigment treated with a polymer, and a true specific gravity of 6 g / cm. ^It has been found that the combination with the magnetic particles having a particle diameter of ³ or less and coated with an electrically insulating resin can achieve them extremely well.

Hereinafter, the main developing method will be described with reference to Examples. FIG. 1 shows an embodiment according to the present invention. In FIG. 1, 1 is a latent image holding member, 21 is a toner supply container, 22 is a non-magnetic sleeve, 23 is a fixed magnet, 24 is a non-magnetic blade, 26 is a magnetic particle circulation region limiting member, 27 is magnetic particles, 28 Is non-magnetic toner, 29
Is a developer collection container part, 30 is a scattering prevention member, 31 is a magnetic member, 32 is a developing region (about 10 mm width in the sleeve circumferential direction centering on the closest part of the latent image holder and the developer carrier), 34 indicates a bias power supply. The sleeve 22 rotates in the b direction, and the magnetic particles 27 circulate in the C direction accordingly. Then, as described later, it is preferable that the upper limit of the circulation area of the magnetic particles 27 is restricted by the magnetic particle circulation area limiting member 26 installed in the toner supply container 21. This causes contact and rubbing between the sleeve surface and the magnetic particle layer, and a nonmagnetic toner layer is formed on the sleeve surface. While the magnetic particles circulate in the C direction, a part of the magnetic particles is regulated to a predetermined amount by the gap between the nonmagnetic blade 24 and the sleeve 22, and is applied onto the nonmagnetic toner layer. That is, the non-magnetic toner is applied on both the surface of the sleeve and the surface of the magnetic particles, and the effect equivalent to that of substantially increasing the surface area of the sleeve is exhibited. The coating amount of the magnetic particles in a non-magnetic blade 24 downstream sleeve surface in the present invention, in order to sufficiently utilize both the magnetic brush and the sleeve 22 surface of magnetic particles is ^{5mg / cm 2 ~100mg / cm 2} , It is preferable that the amount is as small as 10 to 80 mg / cm ² .

In the developing area 32, one of the magnetic poles of the fixed magnet 23 is opposed to the latent image surface to form a clear developing pole,
Toner is fly-developed on the sleeve and from the magnetic particles by an alternating electric field. After development, the magnetic particles and the undeveloped toner are collected in the developing container as the sleeve rotates. Sleeve 22
May be a paper cylinder or a synthetic resin cylinder, but can be used as a developing electrode roller if the surface of these cylinders is subjected to a conductive treatment or is made of a conductor such as aluminum, brass, stainless steel or steel. The gap distance d between the tip of the non-magnetic blade 24 and the surface of the developing sleeve 22 is 50 to 500 μ, preferably 100 to 400 μ. If the distance d is less than 50 μm, the magnetic particles are likely to be clogged and the sleeve is easily damaged. On the other hand, if it is larger than 500 μm, a large amount of non-magnetic toner and magnetic particles are likely to leak out, and it is difficult to form a thin layer.

In FIG. 1, reference numeral 26 is a magnetic particle circulation region limiting member whose lower surface is in contact with the upper surface side of the non-magnetic blade 24 and whose front end surface is an undercut surface.

Denoted at 27 and 28 are magnetic particles and non-magnetic toner that are sequentially accommodated in the toner supply container 21.

The bottom plate of the toner supply container 21 is extended below the developing sleeve 22, which is a toner holding member, to prevent the toner from leaking to the outside. Further, in order to further prevent the leakage of this toner to the outside, the leakage toner repair container portions 29 and C for receiving and restraining the leakage toner are scattered on the upper surface of the extension bottom plate, and scattered along the length of the leading edge of the extension bottom plate. Prevention member
30 are arranged. A voltage described later is applied to this member 30.

The magnetic particles 27 generally have an average particle size of 30 to 100μ, preferably 40 to 80μ. Each magnetic particle may be composed of only a magnetic material, a combination of a magnetic material and a non-magnetic material, or a mixture of two or more kinds of magnetic particles. Then, by first inserting the magnetic particles 27 into the toner supply container 21, the magnetic particles 27 from the toner supply container 21 in which the magnetic particles 27 face the inside of the container 21, that is, the sleeve 22 are arranged. Or, the sleeve 22 is provided at each part of the sleeve surface area from the magnetic member 31 for preventing toner leakage to the tip of the non-magnetic blade 24 serving as a magnetic particle restraining member.
A magnetic particle layer is adsorbed and held by the magnetic field of the magnet 23 inside, and the sleeve surface region is entirely covered as a magnetic particle layer. The non-magnetic toner 28 is charged into the container 21 after the magnetic particles 27 are charged therein, so that a large amount of the non-magnetic toner 28 is stored outside the magnetic particle layer as the first layer with respect to the sleeve 22 and exists as the second layer.

It is preferable that the magnetic particles 27 to be initially charged contain about 2 to 70% (weight) of the non-magnetic toner 28 based on the magnetic particles, but the magnetic particles may be magnetic particles only. Further, once the magnetic particles 27 are adsorbed and held as a magnetic particle layer on the sleeve surface area, they do not substantially flow to one side even if the apparatus is vibrated or the apparatus is tilted to a large extent. The overall covered state is retained.

Thus, in the state where the magnetic particles 27 and the non-magnetic toner 28 are sequentially charged and contained in the container 21 as described above, the magnetic pole of the magnet 23 is
A magnetic brush of magnetic particles is formed in the magnetic particle layer portion near the surface of the sleeve corresponding to the S ₂ position by a strong magnetic field of the magnetic pole.

Further, the magnetic particle layer portion near the tip of the non-magnetic blade 24, which is a magnetic particle regulating member, is regulated based on the effect of gravity and magnetic force and the presence of the non-magnetic blade 24 even if the sleeve 22 is driven to rotate in the direction of arrow b. Due to the balance between the force and the conveying force in the moving direction of the sleeve 22, it accumulates at the point 25 on the surface of the sleeve 22 and forms a stationary layer which can move a little but dwell.

When the sleeve 22 is rotated in the direction of arrow b, the magnetic brush circulates in the direction of arrow c in the vicinity of the magnetic pole S ₂ by appropriately selecting the position of the magnetic pole and the fluidity and magnetic characteristics of the magnetic particles 27. , Forming a circulation layer. In the circulation layer, the magnetic particles that are relatively close to the sleeve 22 rise up from the vicinity of the magnetic pole S ₂ onto the stationary layer on the downstream side of the rotation of the sleeve by the rotation of the sleeve 22. That is, it receives the force of pushing it up. The magnetic particles pushed up, the magnetic particle circulation region limiting member 26 provided on the upper portion of the non-magnetic blade 24, because the upper limit of the circulation region is determined, without riding on the non-magnetic blade 24, It falls due to gravity and returns to near the magnetic pole S ₂ again. In this case, the magnetic particles having a small push-up force, such as being located far from the sleeve surface, may fall before reaching the magnetic particle circulation region limiting member 26. That is, in the circulation layer, the magnetic brush circulates the magnetic particles as indicated by an arrow c due to the magnetic force and the frictional force due to the gravity and the magnetic poles and the fluidity (viscosity) of the magnetic particles.
During this circulation, the magnetic brush successively takes in the non-magnetic toner 28 from the toner layer above the magnetic particle layer and returns to the lower portion inside the developer supply container 21, and thereafter this circulation is repeated with the rotational drive of the sleeve 22. .

As the developing bias voltage 34, an alternating voltage having the same peak voltage on the positive side and the negative side or a DC voltage superimposed on this alternating voltage can be used. For example, with respect to an electrostatic latent image having a dark portion latent image potential of −600 V and a bright portion latent image potential of −200 V, for example, a DC voltage −300 V is superimposed on the sleeve 22 and a peak voltage Vp of a waveform is obtained.
An alternating voltage selected in the range of p300 to 20000 V and frequency 200 to 3000 Hz is applied to hold the photosensitive drum 3 at the ground potential.

Generally, the electric resistance of a magnetic brush is relatively high (10 ⁸ Ωcm
Therefore, the peak voltage width Vpp of the developing bias is preferably high (for example, 800 V or higher), and the frequency is 600 Hz or higher, preferably 800 Hz or higher, and more preferably 1 kHz or higher, which provides sufficient image quality with sufficient density. It was Even if only Vpp is high, if the frequency is low, the density is low and it is difficult to obtain good image quality. In any case, the upper limit of Vpp is determined by the gap discharge limit value of the developing section, and the lower limit is determined by the flight limit value of toner on the sleeve and magnetic particles. With a relatively high resistance developing brush, the peak value of the alternating electric field can be set so that the gap voltage does not reach the discharge start voltage by properly selecting the frequency of the alternating electric field to be applied and the time constant of the developing brush itself. preferable.

The magnetic particles and the resistance value of the magnetic brush described in the present invention are the magnetic brush of about 50 mg / cm ² magnetic particles formed on the developing sleeve 22 by the developing device shown in FIG. It is calculated from the current value flowing when a DC voltage of 200 V is applied to a circuit in which a developing sleeve and a metal drum maintaining a gap of about 300 μm are provided, and a resistance of about 1 MΩ is connected in series with them.

The development in the developing section 32 will be described below regarding the developing method according to the present invention.

2 and 3 are enlarged explanatory views of the developing section in the developing method according to the present invention. 50 is the latent image charge in the dark area on the latent image carrier. 28 is a non-magnetic toner. 34 is an alternating power source on which a DC component is superimposed. 2 shows the case where a plus waveform component of the alternating voltage is added to the sleeve 22, and FIG. 3 shows the case where a minus waveform component of the alternating voltage is added. The polarity of the latent image charge is shown as negative and the polarity of the developer is shown as positive.

Since the resistance of the developing brush 51 is relatively large (greater than about 10 ⁸ Ωcm), the developing brush 51 depends on the charging / discharging time constant of the charge due to the material of the developing brush 51 itself, etc. Alternatively, there is a charge injected by the mirror charge, the latent image electric field on the latent image carrier 3 and the alternating electric field between the latent image carrier 3 and the sleeve 22.

When the electric field due to the latent image charge 50 in the dark portion on the latent image carrier 3 and the electric field due to the alternating electric field coincide with each other, the developing brush 51 is in the maximum sagging state in the sleeve 22 direction.

When the direction of the electric field due to the latent image charge on the latent image carrier 3 and the direction of the electric field due to the alternating electric field do not match, the yielding of the developing brush 51 becomes small.

In any case, as described above, the developing brush is generated by the alternating electric field.
51 is in a fine but violent vibration state, and the fog toner excessively attached to the latent image holding member is rubbed by the developing brush, removed from the latent image holding member 3, and pulled back onto the brush. Further, due to the vibration of the brush, the toner is easily separated from the brush 51 and is easily supplied to the latent image holding member 3, so that the image density is also improved. Also brush 51
The above-mentioned vibration loosens the toner in the brush 51, which contributes to improvement of image density and prevention of ghost. further,
When this vibration state is severe, a part of the magnetic brush separates from the brush or the sleeve, and a reciprocating motion is generated between the latent image carrier and the sleeve surface. The kinetic energy of this reciprocating brush is large and efficient, and the effect of the above-mentioned vibration is expected. The above-described behavior of the magnetic particles in the developing section is the observed development as a result of high-speed photography of 8000 frames per second with a high-speed camera.

 Next, the compound of the general formula (1) will be described.

Specific preferred examples of the compound represented by the general formula (1) include Etc.

The organic pigment used in the present invention, BET specific surface area by nitrogen adsorption method 0.1m ² / g~300m ² / g, preferably 1.0m ² / g~100m ² / g, a known Pigments such as anthraquinone type, quinacridone type, phthalocyanine type,
Various organic pigments such as perylene type, perinone type and azo type can be used.

A specific treatment method of the organic pigment used in the present invention is, for example, the general formula (1) in an aqueous solution containing a surfactant.
A method in which a polymer emulsion obtained by adding the monomer represented by and emulsion-polymerizing is added to an aqueous slurry of an organic pigment, and heat-treated. Alternatively, the organic pigment, the monomer represented by the general formula (1), and the monomer are dissolved,
Various methods such as a method of dispersing a solvent system in which the polymer is insoluble by a ball mill or the like and then precipitating the polymer on the surface of the organic pigment using a polymerization initiator or the like can be mentioned. In the present invention, the former method using a polymer emulsion has obtained particularly preferable results.

The content of the polymer in the organic pigment thus treated is 1 to 80% by weight, preferably 2 to 50% by weight, and particularly 3 to 30% by weight, based on the amount of the organic pigment.

The treated organic pigment is contained in the toner in an amount of 0.2 to 80% by weight, preferably 0.5 to 70% by weight, and particularly 1 to 50% by weight.

As the surfactant for treating the organic pigment in the present invention, conventionally known nonionic surfactants, ionic surfactants,
An amphoteric surfactant is used, and examples of the nonionic surfactant include polyoxyethylene ethers of various fatty acids, polyoxyethylene ethers of higher alcohols,
Alkylphenol polyoxyethylene ethers, sorbitan ester polyoxyethylene ethers, polyoxypropylene polyoxyethylene ethers,
Examples include castor oil polyoxyalkylene ethers and various fatty acid alkylolamides.

The nonionic surfactant used in the present invention also includes a cationic nonionic surfactant that is soluble in an acidic solution such as an amine, or an anionic nonionic surfactant that is soluble in a basic solution such as a carboxyl group. It is preferable.

Further, as the ionic surfactant, aliphatic amine salts,
Quaternary ammonium salts, alkylpyridinium salts,
Higher fatty acid salts, higher alcohol sulfate ester salts, liquid fatty oil sulfate ester salts, salts of aliphatic amines and aliphatic amides, aliphatic alcohol phosphate ester salts, sulfone salts of dibasic fatty acid esters, fatty acid amide sulfonates, Examples thereof include alkyl allyl sulfonates and formalin-condensed naphthalene sulfonates.
Examples of the amphoteric surfactant include those having both an atomic group capable of dissociating into an anion and an atomic group capable of dissociating into a cation in the same molecule, and examples thereof include an alkylamino acid. In the present invention, a nonionic surfactant is used. Particularly preferable results were obtained when using.

The content of these surfactants in the organic pigment varies depending on the shape, size, properties, etc. of the organic pigment, but in the present invention, 0.005 to 30% by weight, preferably 0.01 to 10% by weight, Especially, it was good in the range of 0.05 to 2% by weight. If the content of the surfactant is too small, it is difficult to secure the stability and uniformity of the triboelectric charge quantity, and if it is too large, it becomes easy to absorb moisture, especially when storing or using for a long period of time because various moisture is absorbed. It tends to cause deterioration of physical properties.

As the polymer for treating the organic pigment of the present invention, conventionally known polymers may be used alone or in combination, or as a copolymer. As an example, polystyrene, poly-p-chlorostyrene, polyvinyltoluene,
Polymers of styrene and its derivatives such as polychloromethylstyrene; Polymers of acrylic acid and acrylates such as polymethacrylic acid, polymethylmethacrylate, polyethylmethacrylate and polybutylmethacrylate;
Examples thereof include polyacrylonitrile, polybutadiene, polypropylene, polyethylene, polyester, polyamide, polyimide, epoxy resin, polyvinyl butyral, polyvinyl pyridine, rosin, modified rosin, terpene resin, phenol resin and chlorinated paraffin.

A polymer that is capable of treating the organic pigment and a resin that is compatible with the binder resin are preferable. In this sense, the polymer and the binder resin have the same or similar structure, or various polymers that are a measure of compatibility. It is preferable that the parameters are the same or similar.

The content of these polymers in the organic pigment is 1 to 80% by weight, preferably 2 to 50% by weight, particularly 3 to 30% by weight, based on the amount of the organic pigment.

The organic pigment used in the present invention, BET specific surface area by nitrogen adsorption method 0.1m ² / g~300m ² / g, conventionally known pigments and preferably 1.0m ² / g~100m ² / g For example, various organic pigments such as anthraquinone type, quinacridone type, phthalocyanine type, perylene type, perinone type, and azo type pigments can be used. The addition amount of these treated organic pigments varies depending on the properties and purpose of each compound, but is 0.2 to 80% by weight, preferably 0.5 to 70% by weight, particularly preferably 0.5 to 70% by weight in the toner as an organic pigment containing a surfactant and a polymer. 1-50% by weight is good.

As a specific treatment method of an organic pigment containing a polymer and a surfactant used in the present invention, a polymer emulsion obtained by emulsion-polymerizing a corresponding monomer in an aqueous solution containing a surfactant is used as fine particles. The method of adding to the aqueous slurry and heat treating. Alternatively, the pigment may be suspended in an aqueous solution of a surfactant, heated and stirred to produce a pigment containing a surfactant, and then a polymerization initiator may be used as a core substance to carry out polymerization to obtain a surfactant. , And a method of obtaining a pigment containing a polymer, etc. In the present invention, the former method using a polymer emulsion has obtained preferable results.

As the magnetic particles for toner coating used in the present invention, for example, surface-oxidized or unoxidized metals such as iron, nickel, cobalt, manganese, chromium, rare earths, and alloys or oxides thereof can be used. Further, there is no particular limitation as a manufacturing method thereof.

Further, as a method of coating the surface of the magnetic particles with a resin or the like, a method of dissolving or suspending a coating agent of a resin or the like in a solvent and applying it to a carrier, simply mixing with a powder, etc. Any known method can be applied.

The adhesive substance that adheres to the surface of the carrier varies depending on the toner material. For example, polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, styrene resin, epoxy resin, acrylic resin, polyamide , Polyvinyl butyral, amino acrylate resin and the like are suitable, but not limited thereto.

The amount of the above compound to be treated may be appropriately determined so that the carrier satisfies the above conditions, but generally, the total amount is preferably 0.1 to 30% by weight (preferably 0.5 to 20% by weight) based on the carrier of the present invention. .

On the other hand, as the binder resin for the toner used in the present invention, a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like, or a substituted polymer thereof;
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 Coalesce, styrene-butyl methacrylate copolymer,
Styrene-acrylic-amino acrylic copolymer, styrene-amino acrylic copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene- Vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-
Styrene-based copolymers such as maleic acid copolymers and styten-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, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. can be used alone or in combination. .

In the toner, any suitable pigment or dye can be used as a colorant. For example, there are known dyes and pigments such as carbon black, iron black, phthalocyanine blue, ultramarine blue, quinacridone, and benzidine yellow.

Further, as a charge control agent, an amino compound, a quaternary ammonium compound and an organic dye, particularly a basic dye and a salt thereof, benzyldimethyl-hexadecyl ammonium chloride, decyl-trimethyl ammonium chloride,
Nigrosine base, nigrosine hydrchloride, safranine γ and crystal violet, metal-containing dyes, salicylic acid-containing compounds may be added. Further, magnetic powder may be added to the extent that the effects of the present invention are not impaired.

The above-described toner composition is generally used for mixing-
It may be used for the toner by the pulverization method, and it is particularly preferable because it can be used for the wall material and / or the core material of the microcapsule toner.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples. Parts shown in the examples are parts by weight.

 As the developing device, the one shown in FIG. 1 was used.

In the apparatus of the embodiment, the N-type OPC photosensitive drum 3 having a diameter of 80 mm rotates in the direction of arrow a at a peripheral speed of 210 mm / sec. 22 is an outer diameter of 32 mm that rotates at a peripheral speed of 210 mm / sec in the direction of arrow b, and a thickness
A 0.8 mm sleeve made of stainless steel (SUS304), the surface of which was subjected to irregular sandblasting using # 600 alundum abrasive grains to make the surface roughness in the circumferential direction 0.8 μm (Rz =).

On the other hand, a ferrite sintered type magnet 23 is fixedly arranged in the rotating sleeve 22, and the magnetic pole arrangement is such that the maximum value of the surface magnetic flux density is about 900 gauss as shown in FIG. The non-magnetic blade 24 was made of non-magnetic stainless steel having a thickness of 1.2 mm.
The blade-sleeve gap was 400μ.

On the surface of the photosensitive drum 3 facing the sleeve 22,
As an electrostatic latent image, a charge pattern of -150 V in the dark part and -150 V in the light part was formed, and the distance from the sleeve surface was set to 300 μm. Then, a frequency of 1800 Hz is generated by the power source 34 for the sleeve,
Development was carried out by applying a voltage having a peak-to-peak value of 1.4 KV and a center value of -300V.

Example 1 (A) To a flask equipped with a stirrer, a thermometer, a dropping funnel, a Dimroth condenser, and an Ar introduction tube, 150 parts by weight of a 5% aqueous solution of a nonionic surfactant having an HLB of 20 was added and heated to 80 ° C. Then, 100 parts by weight of dimethylaminoethyl methacrylate (the above compound (b)) and 100 parts by weight of a 1% aqueous solution of potassium persulfate were added dropwise from separate dropping funnels while passing Ar gas. After the dropwise addition was completed, heating was continued for 60 minutes and then cooled to room temperature to obtain a milky-white polymer emulsion.

(B) Commercially available copper-phthalocyanine pigment (CIPigment
After adding 100 parts of blue 15) to HCl aqueous solution of pH = 4,
5 parts of nonionic polymer emulsion synthesized in (A) was added and heated to 80 ° C. with vigorous stirring, and further NaOH was added to adjust pH =
After setting to 11, repeated filtration and washing with water to obtain a treated product.

(C) The toner treatment method was the copper-phthalocyanine pigment obtained in (B) 5 parts by weight styrene-diethylaminoethyl methacrylate copolymer 60 parts by weight styrene-butadiene copolymer 40 parts by weight, and a mixture containing these components was roll-milled. At 150
The mixture was heated and kneaded at 15 ° C. for 15 minutes, cooled, coarsely crushed with a hammer mill, and then finely pulverized with a fine pulverizer by an air jet system. Further, air classification was performed to obtain blue particles having an average particle size of 13 μ, and 1% by weight of colloidal silica was added to obtain a positively chargeable toner.

(D) Magnetic particles were obtained by coating the surface of 100 parts by weight of ferrite particles having a true specific gravity of 6 g / cm ³ or less between particle sizes of 200 to 300 mesh with 1.5 parts of styrene-butyl acrylate copolymer.

(E) Next, 12 parts by weight of the above toner and 100 parts by weight of magnetic particles were mixed and charged into the developing device shown in FIG. 1. As a result, a moist and uniform image having a high image density and a good image free from fog were obtained. Was given. When this development state was photographed with a high-speed camera, it was observed that the flight development was smoothly performed on both the sleeve and the magnetic brush.

When the image was continuously developed 1000 times, the image was as clear as the initial one.

Example 2 (A) Example 1 (A) except that 100 parts by weight of diethylaminoethyl methacrylate (the above compound example (C)) was used instead of 100 parts by weight of dimethylaminoethyl methacrylate in Example 1 (A). A nonionic polymer emulsion was obtained in the same manner as in.

(B) The same method as in Example 1 except that 100 parts by weight of the copper-phthalocyanine pigment (CIPigment blue 15) in Example 1 (B) was replaced with 100 parts of another copper-phthalocyanine pigment (CIPigment Green 7). The polymer emulsion obtained in (A) was treated.

(C) Example 1 (D) except that the toner treatment method is CI Pigment Green 7 5 parts by weight obtained in (B) styrene-diethylaminoethylmethacrylate copolymer 70 parts by weight styrene-butadiene copolymer 30 parts by weight When it was performed in the same manner as in (E) and (E), similarly good results were obtained.

Example 3 (A) In Example 1 (A), 100 parts by weight of dimethylaminoethyl methacrylate was used instead of di-n-propylaminoethyl methacrylate (Compound Example (d)) 40.
A nonionic polymer emulsion was obtained in the same manner as in Example 1 (A) except that the amount was 60 parts by weight and the amount of methyl methacrylate was 60 parts by weight.

(B) Same as Example 1 (B) except that 100 parts by weight of the copper-phthalocyanine pigment (CIPigment blue 15) in Example 1 (B) is used as 100 parts by weight of the monoazo pigment (CIPigment Red 170). The polymer emulsion obtained in (A) was treated.

(C) CI Pigment Red 170 obtained by the method of (B) 2 parts by weight Styrene-maleic acid copolymer 100 parts by weight 3,5-di-tert-butyl salicylic acid chromium complex 1
Good results were obtained in the same manner as in (D) and (E) of Example 1 except that the weight part was used.

Example 4 (A) A polymer emulsion was obtained in the same manner as in Example 1 (A).

(B) A treated pigment was obtained in the same manner as in Example (B).

(C) Toner formulation: 3 parts by weight of the copper phthalocyanine pigment obtained in (B) and 100 parts by weight of polyethylene wax were sufficiently kneaded and then granulated to obtain a spherical state having an average particle size of 14 μ. Next, diethylaminoethyl methacrylate-styrene copolymer (copolymerization weight ratio 10:90) was added to the spherical particles as D.
A microcapsule toner was obtained by coating the MF solution by a phase separation method and further adding 1% by weight of colloidal silica.

(D) Magnetic particles were obtained in the same manner as in Example 1 (D).

(E) Next, 15 parts by weight of the microcapsule toner and 100 parts by weight of magnetic particles were mixed, and the same procedure as in Example 1 was carried out, and good results were obtained.

Example 5 (a) To a flask equipped with a stirrer, a thermometer, a dropping funnel, a condenser, and an Ar introduction tube, 150 parts by weight of a 5% aqueous solution of polyoxyethylene sorbitan trioleate was added and heated to 80 ° C. Thereafter, the mixture was stirred while passing Ar gas, and 70 parts by weight of styrene, 30 parts by weight of methyl methacrylate, and 100 parts by weight of a 2% aqueous solution of potassium persulfate were dropped from separate dropping funnels. After the dropwise addition was completed, the mixture was heated and stirred for 30 minutes and then cooled to room temperature to obtain a polymer emulsion containing polyoxyethylene sorbitan trioleate.

(B) Commercially available copper-phthalocyanine pigment (CIPigment
blue 15) After adding 100 parts by weight of HCl = 5 aqueous solution, 20 parts by weight of the polymer emulsion synthesized in (a) was added and the temperature was raised to 50 ° C. with stirring, and NaOH was further added to adjust pH = 10.
After that, filtration and washing with water were repeated to obtain a copper-phthalocyanine pigment containing polyoxyethylene sorbitan trioleate and styrene-methyl methacrylate.

(C) As a toner processing method, the copper-phthalocyanine pigment obtained in (b) 5 parts by weight Styrene-butyl acrylate resin 80 parts by weight Styrene-butadiene resin 20 parts by weight Dimethylaminoethyl methacrylate resin 2 parts by weight Polypropylene resin 4 parts by weight is roll-milled. After heating and kneading at 160 ° C for 15 minutes, the mixture was cooled, coarsely crushed with a hammer mill, and then finely pulverized with a fine pulverizer by an air jet system. Further, air classification was performed to obtain yellow particles having an average particle diameter of 12μ, and 1% by weight of colloidal silica was added to obtain a positively charged toner.

(D) 100 parts by weight of ferrite particles having a true specific gravity of 6 g / cm ³ or less between particle sizes of 200 to 300 mesh were coated with 1.5 parts by weight of a styrene-butyl acrylate copolymer to obtain magnetic particles.

(E) Next, 15 parts by weight of the above toner and 100 parts by weight of magnetic particles were mixed and charged into the developing device shown in FIG. 1. As a result, a moist and uniform image having high image density and a good image free from fog were obtained. Was given. When this development state was photographed with a high-speed camera, it was observed that the flight development was smoothly performed on both the sleeve and the magnetic brush.

Example 6 (a) In Example 5 (a), 150 parts by weight of a 5% aqueous solution of polyoxyethylene sorbitan trioleate was used as 150 parts by weight of a 10% aqueous solution of triethanolamine stearate, and 70 parts by weight of styrene and methyl were used. A polymer emulsion containing triethanolamine stearate was obtained in the same manner as in Example 5 (a) except that 30 parts by weight of methacrylate was 90 parts by weight of styrene and 10 parts by weight of 2-ethylhexyl methacrylate.

(B) Triethanolamine stearate and styrene-2 were prepared in the same manner as in Example 1 (b) except that 100 parts by weight of the copper-phthalocyanine pigment was changed to 150 parts by weight of the monoazo red pigment in Example 5 (b). A monoazo red pigment containing ethylhexyl methacrylate was obtained.

(C) Implemented except that the toner treatment method is 70 parts by weight of styrene-n-butyl acrylate resin 30 parts by weight of styrene-butadiene resin 4 parts by weight of diisopropylaminoethyl methacrylate resin 70 parts by weight of the monoazo red pigment obtained in (b) When performed in the same manner as in (d) and (e) of Example 5, similarly good results were obtained.

〔effect〕

As described above, according to the present invention, in the developing device using magnetic particles, the general formula (1) (In the formula, R ₁ , R ₂ and R ₃ each represent a hydrogen atom, a substituted or unsubstituted hydrocarbon group, and n represents an integer of 1 or more. Provided that R ₁ and R ₂ are simultaneously hydrogen atoms. By using a non-magnetic toner containing an organic pigment treated with a polymer synthesized from a monomer represented by the formula (3) or a surfactant and an organic pigment treated with a polymer, a high image density and no fog can be obtained. It was possible to obtain good image quality with good tonality and no negative characteristics. Further, by effectively distributing the toner that contributes to the development on the sleeve and the magnetic particles and performing the flight development from both of them, it was possible to achieve a development efficiency of nearly 100% in an alternating electric field. This makes it possible to reduce the size, weight and simplification of the developing device configuration. Further, the brush of magnetic particles according to the present invention was able to remove the ground fog toner adhering to the latent image carrier by contacting and vibrating the latent image carrier by at least an alternating electric field.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a developing device according to the developing method according to the present invention, and FIGS. 2 and 3 are enlarged explanatory views of a developing unit according to the developing method according to the present invention. 3 ... Latent image holding member, 21 ... Developer supply container, 22 ... Non-magnetic sleeve, 23 ... Fixed magnet, 24 ... Non-magnetic blade, 26 ... Magnetic particle circulation region limiting member, 27 ... Magnetic Particles, 28 ... Non-magnetic toner, 29 ... Developer collection container part, 30 ... Scatter prevention member, 31 ... Magnetic member, 32 ... Development area, 34 ... Bias power supply, 50 ... Electrostatic latent Image, 51 …… Magnetic brush.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03G 15/09 G03G 9/10

Claims (1)

(57) [Claims] 1. An alternating electric field is applied between a latent image carrier and a latent image carrier for holding an electrostatic latent image, and a developing region of the developer carrier opposite to the latent image carrier. However, in the image forming method in which the electrostatic latent image is developed with the non-magnetic toner containing at least the binder resin and the pigment, the non-magnetic toner is mixed with the general formula ( 1) (In the formula, R ₁ , R ₂ and R ₃ each represent a hydrogen atom, a substituted or unsubstituted hydrocarbon group, and n represents an integer of 1 or more. Provided that R ₁ and R ₂ are simultaneously hydrogen atoms. It contains an organic pigment or a surfactant treated with a polymer synthesized from a monomer represented by the formula (1) and an organic pigment treated with the polymer, and has a true specific gravity of 6 g / cm ³ or less, In addition, by using magnetic particles coated with an electrically insulating resin, a developing area of the developer carrier, a magnetic brush is formed so that the amount of the magnetic particles present is 5 to 100 mg / cm ^2, and And developing the latent image while reciprocating non-magnetic toner between the latent image holder and the surface of the developer bearing member and the surface of the magnetic brush while bringing the latent image holder and the magnetic brush into contact with each other. Image forming method.