JPH0473659A - Developer and image forming method - Google Patents

Abstract

PURPOSE:To maintain uniform developing property independently of temp. and humidity by combining a toner contg. a binding resin having a specified acid value and contg. units of a polymerizable monomer having a specified acid group, magnetic particles having a specified bulk density and a metallic complex salt type monoazo dye having a hydrophilic group with inorg. fine powder. CONSTITUTION:This developer contains a toner contg. a binding resin having 1-70 acid value, magnetic particles having >=0.35g/cm<3> bulk density and a metallic complex salt type monoazo dye having a hydrophilic group and inorg. fine powder treated with silicone oil or silicone varnish. The binding resin contains units of a polymerizable monomer having a carboxyl group or the acid anhydride thereof as an acid group by 2-30pts.wt. per 100pts.wt. of the resin. This developer maintains uniform developing property independently of temp. and humidity in a simplified developing device, does not scratch the surface of a coated sleeve in repeated developing operations and can prolong the service life of the sleeve.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is utilized in the field of technology for developing electrostatic latent images with a developer, and in particular, image formation in which development is performed by restraining the developer with magnetic force. The present invention relates to a method and a developer used therein.

[Prior art j Conventionally, as an electrophotographic method, U.S. Patent No. 2.297,69
A number of methods are known as described in Japanese Patent Publication No. 1, Japanese Patent Publication No. 42-23910, Japanese Patent Publication No. 43-24748, etc., but generally, they utilize photoconductive substances,
An electrical latent image is formed on the photoreceptor by various means, then the latent image is developed using toner, and if necessary, the toner image is transferred to a transfer material such as paper, followed by heating, pressure, or heating. The toner is fixed by pressure or solvent vapor to obtain a copy, and the toner remaining on the photoreceptor without being transferred is cleaned by various methods, and the above-mentioned steps are repeated.

In recent years, such copying devices have begun to be used not only as office copy machines for copying original documents, but also as printers for output from computers, and as personal copies for individuals. There are a wide variety of methods.

Therefore, smaller size, lighter weight, higher speed, and higher reliability are being strictly pursued, and machines are being constructed from simpler elements in various respects. As a result, by simplifying and downsizing the developing device configuration, the performance required of the toner of the one-component developer becomes more advanced, and if the performance of the toner of the developer cannot be improved, the performance will become even higher. The old machines are no longer viable.

In particular, for -component magnetic toner, the fact that the toner itself has magnetic force is used to feed the toner onto the toner carrier and transport the toner to the development site on the toner carrier using a stirring bar. By eliminating physical means such as mechanical means and magnetic carriers and replacing the force with the magnetic force of the toner itself and the repulsive force of the magnet installed on or inside the toner carrier, we have achieved the ultimate goal. There are many examples of simplification of equipment.

However, -component type developers generally have little chance of being charged due to friction, and since the toner particles of the developer contain magnetic powder, their charge retention is weak.

Therefore, in systems that do not include mechanical or physical developer conveyance means, as described above, there are problems such as difficulty in uniformly charging the toner or difficulty in uniformly coating the toner on the developer carrier. It had

In particular, in a developing device that uses a cylindrical rotating developer carrier known for boat fishing, almost no developer conveying force is generated in the direction parallel to the rotation axis, so the toner is not uniformly charged. , it is extremely difficult to uniformly apply the developer onto the developer carrier, and efforts have been made to find magnetic particles, charge control agents, etc. that should be added to the developer.
I haven't reached the point where I'm fully satisfied.

In addition, a developing device that visualizes a latent image formed on the surface of a photosensitive drum as an electrostatic latent image carrier using a magnetic toner as a one-component developer uses friction between magnetic toner particles and a developer carrier. The friction between the sleeve and the magnetic toner particles gives the magnetic toner particles an electric charge of opposite polarity to the electrostatic image charge formed on the photosensitive drum, and the magnetic toner is applied thinly onto the sleeve to form a bond between the photosensitive drum and the sleeve. The magnetic toner is conveyed to the developing area formed by the photosensitive drum, and in the developing area, the magnetic toner is caused to fly by the action of the magnetic field generated by the magnet fixed in the sleeve, and the static 1! A device that visualizes a latent image is known.

However, in all of the above-mentioned developing devices, it is necessary to form a relatively thin and uniform toner layer on the sleeve, but it depends on the environmental conditions, toner physical properties, sleeve surface condition, etc. This often results in unevenness, especially in low-humidity environments.

In addition, as the developer is repeatedly rubbed against the sleeve as copies are made, non-developing substances such as additives to improve toner fluidity and carriers in two-component toners may accumulate on the sleeve, or during development. The surface condition of the sleeve changes because the binder resin in the agent forms a film on the sleeve, making the developing performance of the developer unstable or the conveyance of the developer to the electrostatic latent image surface unstable. There was a problem of becoming

In addition, if fine powder is present in the toner, the fine powder toner will selectively accumulate near the surface of the sleeve due to the difference in developability, and the original toner will form a layer on top of it, which will cause the appropriate wtFL required for development. There has been a problem that it becomes difficult to obtain a sufficient amount of powder, and a difference in concentration occurs between the part where the fine powder layer is formed and the normal part, which is called sleeve memory.

Here, the sleeve memory will be explained using FIG. 1. When the original shown in Fig. 1(B) is developed after 100 sheets of the original shown in Fig. 1(A) are developed in succession, the toner on the sleeve corresponding to the white background other than area X of the original shown in Fig. 1(A) Portion C of area Y in FIG. 1(B), which has been developed, has a lower image density than other image areas. The development in which an image like this portion C is formed is called sleeve memory.

In order to prevent such changes in the surface condition of the sleeve,
For example, one that forms a film containing an inorganic polymeric carbon fluoride (Japanese Patent Laid-Open No. 57-66443), and one that forms a resin with good mold release properties in which silica is dispersed (Japanese Patent Laid-Open No. 58-66443).
178380), organic silicone polymers, aliphatic fluorine-containing compounds, styrene resins, and polyphenylene oxides, and a metal complex having di- to hexadentate ligands. (Japanese Unexamined Patent Publication No. 57-76558) has been proposed in which changes in the surface condition are prevented by coating the sleeve surface with a substance having particularly high mold releasability. However, these proposals have not been able to solve the problems of conventional sleeve memories and the like mentioned above.

Further, a coated sleeve in which a synthetic resin or the like is coated on the sleeve surface is clearly relatively softer than a conventionally used sleeve made of aluminum or 5LIS. Therefore, during repeated development operations, the developer is pressed against the surface of the developer carrier, which is particularly noticeable in the case of magnetic developers containing magnetic materials, and the surface of the developer carrier may be unevenly polished or scratched. There has been a problem in that the inherent performance of the coat sleeve tends to deteriorate due to sticking or some of the developer adhering to the coat sleeve.

[Problems to be Solved by the Invention] It is an object of the present invention to solve the above-mentioned drawbacks, and to solve the above-mentioned problems without sleeve memory, without damaging the coat sleeve, without causing developer to stick, and even in the direction parallel to the rotation axis. The present invention provides a developer that can be uniformly carried on the surface of a sleeve, and an image forming method using the developer.

A further object of the present invention is to provide a developer and an image forming method that are not dependent on the environment and that do not impair uniform developability even with changes in temperature and humidity.

[Means and effects for solving the problem, that is, according to the present invention, the above object is to contact the developer in the developer storage chamber and carry the developer on the surface, so that the static 1! In an image forming method using a developing device in which a coating layer containing conductive fine particles is formed on the surface of a developer carrier conveyed to a development area formed between the developer and the latent image carrier, the developer is ■A polymerizable monomer unit containing an acid group consisting of a carboxyl group or its acid anhydride is added to the binder resin 10
It contains 2 to 30 parts by weight in 0 parts by weight, and has an acid value of 1 to 70.
a toner containing at least a binder resin, magnetic particles having a bulk density of 0.35 g/cm" or more, and a metal complex type monoazo dye having a hydrophilic group; and an inorganic fine powder treated with silicone oil or silicone varnish. This is achieved by a developer and an image forming method characterized by containing a body.

The present inventors have discovered that in order to achieve uniform developing performance in a simplified developing device, and to extend the life of the coated sleeve without damaging the surface even during repeated developing operations, As a result of intensive investigation into what kind of composition would be preferable for the agent, the following assumptions were reached, although the cause has not yet been fully elucidated. That is, in order to achieve uniform developability, the slipperiness, fluidity, high developing power, speed and ease of triboelectrification of the developer are likely to be important factors; In order to obtain a toner with good slipperiness and fluidity, it seems preferable to use magnetic particles with high bulk density and a metal complex type monoazo dye as a charge control agent, and also add a small amount of polyalkylene. It has been found that this is more preferable, and that by using a resin containing an acid group as the resin that binds them, the speed and ease of contact charging can be improved. In addition, as an external additive for the toner, in order not to impair the following characteristics and to prevent uneven polishing or damage to the surface of the coat sleeve, inorganic fine powder whose surface has been treated with silicone oil or silicone varnish may be used. It has also been found that it is more preferable to use the body.

Hereinafter, a developing device used in the present invention will be explained based on the accompanying drawings.

FIG. 2 is a sectional view of an example of the developing device of the present invention.

1 in the figure is a static image that carries an electrostatic latent image and rotates in the direction of arrow A. E. A photosensitive drum as a latent image carrier, which can be used with or without an insulating layer on its surface, and of course is not limited to a drum shape, but can also be sheet-shaped or belt-shaped.

Reference numeral 2 denotes a sleeve as a developer carrier that carries toner 5 on its surface and rotates in the direction of arrow B. A multipolar permanent magnet 3 is fixed inside the sleeve 2 so as not to rotate. Further, on the surface of the sleeve 2, a coating layer 10 containing conductive fine particles, which will be described later, has a thickness of approximately 0.5 μm to 30 A1.
It is formed to a thickness of . Reference numeral 4 denotes a developer storage chamber that stores the toner 5 and brings the toner 5 into contact with the surface of the sleeve 2 . Reference numeral 6 denotes a doctor blade as a member that regulates the layer of toner 5 on the surface of the sleeve 2 carried in the developer storage chamber 4 to a predetermined thickness, and the gap between the surface of the sleeve 2 and the doctor blade 6 is about 50 μm. ~500 μm.

When the developing device configured as described above is started and the sleeve 2 rotates in the direction of arrow B, the toner 5 in the developer storage chamber 4 or the surface of the sleeve 2 and the toner 5 contact friction causes the photosensitive drum to be rotated. A toner 5 is charged with a polarity opposite to that of the electrostatic latent image on the toner 1 and applied to the surface of the sleeve 2. The toner layer applied to the sleeve surface is further coated into a uniform and thin layer (
The layer thickness is regulated to be approximately 30 μm to 300 μm), and the photosensitive drum 1 and the sleeve 2 are conveyed to a developing area.

Furthermore, by applying an AC bias between the sleeve 2 and the surface of the photosensitive drum 1 in the development area, the toner 5 on the sleeve 2 may be caused to fly toward the photosensitive drum.

Here, the coating 10 formed on the sleeve surface will be explained.

The film 10 used is one in which the film-forming polymeric material contains conductive fine particles.

As the conductive fine particles, carbon fine particles, carbon fine particles and crystalline graphite, or crystalline graphite are preferable.

The crystalline graphite used in the present invention can be roughly divided into natural graphite and artificial graphite. Artificial graphite is produced by solidifying pitch coke with tar pitch, etc., firing it once at about 1200℃, putting it into a graphitization furnace, and treating it at a high temperature of about 2300℃, which causes carbon crystals to grow and turn into graphite. . Natural graphite is produced from underground after being completely graphitized by natural geothermal heat and high underground pressure over a long period of time. These graphites have various excellent properties and therefore have a wide range of industrial uses. Graphite is
A very soft and slippery crystalline mineral with a dark gray or black luster. It is used in pencils, etc., and is heat resistant and chemically stable, so it is used as powder, solid, and paint for lubricants, fire resistance, electrical materials, etc. It is used in the form of The crystal structure includes hexagonal crystals and rhombohedral crystal structures, and has a completely layered structure. Regarding electrical properties, free electrons exist between carbon and carbon bonds, making it a good conductor of electricity. Note that the graphite used in the present invention may be either natural or artificial.

Furthermore, the graphite used in the present invention has a particle size of 0.5 μm.
~10 μm is preferred.

Examples of film-forming polymeric materials include thermoplastic resins such as styrene resins, vinyl resins, polyethersulfone resins, polycarbonate resins, polyphenylene oxide resins, polyamide resins, fluororesins, cellulose resins, and acrylic resins, and epoxy resins. Thermosetting resins or photocurable resins such as resins, polyester resins, alkyd resins, phenol resins, melamine resins, polyurethane resins, urea resins, silicone resins, and polyimide resins can be used. Among them, those with mold release properties such as silicone resins and fluororesins, or those with excellent mechanical properties such as polyether sulfone, polycarbonate, polyphenylene oxide, polyamide, phenol, polyester, polyurethane, and styrene resins are more preferable. .

Conductive amorphous carbon is defined as ``an aggregate of crystallites formed by burning or thermally decomposing a hydrocarbon or carbon-containing compound in an insufficient supply of air.'' In particular, it has excellent electrical conductivity, and is widely used because it can be filled into polymeric materials to impart electrical conductivity, and it is possible to obtain a desired electrical conductivity to some extent by controlling the amount added. The particle diameter of the conductive amorphous carbon used in the present invention is preferably 10 μm to 80 μm, more preferably 15 μm to 40 μm.

Next, the developer used in the above-mentioned developing device will be explained.

Various resins can be used as the binder resin having acid groups according to the present invention, but the molecular weight distribution of the THE soluble portion by GPC is
A resin that satisfies n)≧5, has a peak in the molecular weight range of 2,000 to 10,000, and has a peak or shoulder in the molecular weight range of 1,500 to 100,000 is preferable. This is T
HF-soluble components with a molecular weight of 10,000 or less mainly affect blocking properties, adhesion to photoreceptors, and filming properties, and THF-soluble components with a molecular weight of 10,000 or more mainly affect This is based on the fact that it affects fixability.

Further, a copolymer containing an acid group consisting of a carboxyl group or its acid anhydride group may be included in either or both of the molecular weight distribution regions.

In the present invention, the molecular weight of the peak and/or shoulder of a chromatogram by GPC (gel permeation chromatography) is measured under the following conditions.

That is, the column was stabilized in a heat chamber at 40°C, and THF was added to the column at this temperature as a solvent.
(Tetrahydrofuran) is flowed at a flow rate of 1 mρ per minute, and a THF sample solution of the resin adjusted to a sample concentration of 0.05 to 0.6% by weight is injected at 50 to 200 iL°C for measurement. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithm value and the count number of a calibration curve prepared using several types of monodisperse polystyrene standard samples. Standard polystyrene samples for creating a calibration curve include, for example, polystyrene samples manufactured by Pressure Chemical Co.
l0"4X1031.75X10'5, lXl
0', 1. lXl0', 3. 9X10'
8.6X10', 2X10', 4.48×
It is appropriate to use at least 10 standard polystyrene samples. Further, an RI (refractive index) detector is used as a detector.

In addition, as a column, in order to accurately measure the molecular weight range of 10'' to 4×106, it is recommended to combine multiple commercially available polystyrene gel columns (for example, μmstyragel 500, 10310' manufactured by Waters).
10' combination, 5hodexK manufactured by Showa Denko
F-80M, KF-802, 803゜804.8
05 combination or TSKgelG manufactured by Toyo Soda
IOOOH,G 2000H,G 2500H,G
3000H, G4000H, G5000H, G6000
A combination of H, G7000H, and GMH is preferred.

The weight percent based on the binder resin with a molecular weight of 10,000 or less of the present invention is the molecular weight 1' of the chromatogram by GPC.
Cut out a portion with a molecular weight of less than 5,000, calculate the weight ratio with the cutout with a molecular weight of 10.000 or more, and use the weight percent of the THF-insoluble content described above to calculate the weight percent with respect to the entire binder resin.

Examples of the acid group-containing polymerizable monomer that can be used in the present invention include the following.

α, β-unsaturated carboxylic acids such as acrylic acid and methacrylic acid; α, β-unsaturated carboxylic acids such as maleic acid, butyl maleate, octyl maleate, fumaric acid, and butyl fumarate.
Unsaturated dicarboxylic acids or half esters thereof; n
Examples include alkenyldicarboxylic acids such as -butenylsuccinic acid, n-octenylsuccinic acid, butyl n-butenylsuccinate, n-butenylmalonic acid, n-butenyladipic acid, and half esters thereof. Preferred are anhydrizable dicarboxylic acids and derivatives thereof.

In this case, the amount of the polymerizable monomer containing acid groups is preferably 2 to 30 parts by weight based on the total amount of the binder resin, and the acid value of the entire binder resin is preferably 1 to 70, more preferably 5 to 50. .

The method for measuring acid value used in the present invention is shown below.

The acid value is measured according to JIS K-0670.

Weigh 2 to 10 g of the sample into a 200 to 300 mA Erlenmeyer flask, and add about 50 mj2 of a mixed solvent of ethanol:benzene = 1:2 to dissolve the resin. If the solubility is poor, a small amount of acetone may be added. Pre-standardized N/1 using phenolphthalein indicator
Titrate with 0-potassium to ethanol solution, and calculate the acid value from the consumed amount of alcoholic potassium solution using the following formula (3).

Acid value = KOH (mg, number) X N Examples include things like.

For example, styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p
-Phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-
Butylstyrene, pn-hexylstyrene, pn-
Octylstyrene, pn-nonylstyrene, pn-
Styrene and its derivatives such as decylstyrene and p-n-dodecylstyrene; Ethylenically unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; Unsaturated polyenes such as butadiene; Vinyl chloride, vinylidene chloride, vinyl bromide , vinyl halides such as vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylate n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate,
α-methylene aliphatic monocarboxylic acid esters such as phenyl methacrylate, dimethylamine ethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acrylic acid n
- Acrylic acid esters such as octyl, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether;
Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinylindole, and N-vinyl pyrrolidone;
Vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide; single or double vinyl monomers
Used for more than one person.

Among these, combinations of monomers that result in styrene copolymers and styrene-acrylic copolymers are preferred.

Further, as the crosslinkable monomer, a monomer having two or more polymerizable double bonds is mainly used.

The vinyl copolymer used in the present invention is preferably a polymer crosslinked with a crosslinkable monomer as exemplified below.

Aromatic divinyl compounds, such as divinylbenzene, divinylnaphthalene, etc.; diacrylate compounds linked with an alkyl chain, such as ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1
, 4-butanediol diacrylate, 1,5-bentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and the above compounds in which the acrylate is replaced with methacrylate; containing an ether bond Diacrylate compounds linked with alkyl chains, such as diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate,
Polyethylene glycol #400 diacrylate, polyethylene glycol #600 diacrylate, dipropylene glycol diacrylate, and the above compounds in which the acrylate is replaced with methacrylate; diacrylate compounds connected by a chain containing an aromatic group and an ether linkage such as polyoxyethylene (2)-2,2-
Bis(4-hydroxyphenyl)propane diacrylate, polyoxyethylene (4)-2,2-bis(4-hydroxyphenyl)propane diacrylate, and the above compounds in which the acrylate is replaced with methacrylate: and , polyester type diacrylate compounds, for example, the trade name MANDA (Nippon Kayaku). Examples of polyfunctional crosslinking agents include pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, oligoester acrylate, and compounds in which the acrylate of the above compounds is replaced with methacrylate; allyl cyanurate,
and triallyl trimellitate.

These crosslinking agents are preferably used in an amount of about 0.01 to 5 parts (more preferably about 0.03 to 3 parts) per 100 parts of other monomer components.

Among these crosslinking monomers, aromatic divinyl compounds (particularly divinylbenzene),
Mention may be made of chain diacrylate compounds containing aromatic groups and ether linkages.

The method for synthesizing the binder resin used in the present invention is basically preferably a method of synthesizing two or more types of polymers.

That is, it is a method in which a first polymer that is soluble in THF and soluble in a polymerization monomer is dissolved in a polymerization monomer, and the monomer is polymerized to obtain a resin composition. In this case, a composition is formed in which the former and latter polymers are uniformly mixed.

The first polymer soluble in THF is preferably subjected to solution polymerization or ionic polymerization, and the second polymer for producing a component insoluble in THF is prepared under the conditions in which the first polymer is dissolved. It is preferable to synthesize by suspension polymerization or bulk polymerization in the presence of a crosslinking monomer. The first polymer is preferably used in an amount of 10 to 120 parts by weight (preferably 20 to ioo parts by weight) based on 100 parts by weight of the polymerizable monomer for producing the second polymer.

Solvents used in solution polymerization include xylene, toluene,
Cumene, cellosolve, isopropyl alcohol, benzene, etc. are used. In the case of the styrene monomer, xylene, toluene or cumene is appropriately selected depending on the desired polymer to be produced by zero polymerization. Further, the initiator is di-tert-butyl peroxide, tert-butyl peroxybenzoate, benzoyl peroxide, 2,
2゛-azobisisobutyronitrile, 2.2°-azobis(2,4 dimethylbaret nitrile), etc. are monomers 10
0 parts by weight. 1 part by weight or more (preferably 0.
(4 to 15 parts by weight). The reaction temperature varies depending on the solvent, initiator, and polymer to be polymerized, but is preferably carried out at 70°C to 180°C. In solution polymerization, 30 parts by weight of monomer per 100 parts by weight of solvent is used.
It is preferable to use 400 parts by weight to 400 parts by weight.

It should be noted that when solution polymerization is carried out using α, β-unsaturated dicarboxylic acids or half esters thereof, it has been found that cyclization due to anhydration occurs to some extent when the temperature is raised after the reaction is completed and the reaction solvent is evaporated. This was also confirmed by IR in the present invention.

When this copolymer containing an acid anhydride group is used as the first polymer and suspension polymerization is performed in an aqueous solution, the acid anhydride group opens to form a dicarboxylic acid.

In the present invention, the binder resin may be composed only of the resin containing acid groups as described above, but the binder resin may also be a mixture with other resins. Specific examples include styrene-acrylic copolymer resin, polyester resin, polyether resin, polyurethane resin, rosin-modified phenol resin, cellulose resin, and epoxy resin. However, in this case, in order to fulfill the purpose of the present invention, it is preferable that the resin containing acid groups is contained in an amount of 50% by weight or more based on the total binder resin.

The magnetic particles according to the present invention have a bulk density of 0.35
g/cm" or more is preferable.

The present inventors believe that the reason why the toner according to the present invention exhibits the above effects is due to the uniform dispersion of magnetic particles in the toner. If uniform dispersion is not achieved, each toner particle will have an uneven specific gravity distribution and charge distribution, which will lead to poor slipperiness and fluidity, resulting in decreased developability and non-uniformity. It is estimated that this will happen.

The bulk density of the magnetic material can be understood to indirectly indicate the amount of aggregates of magnetic particles, that is, the dispersibility.

If the bulk density of the magnetic material is less than 0.35 g/cm,
A large number of aggregates exist in the magnetic material, making it difficult to obtain sufficient dispersibility in the developer binding resin. This is thought to cause uneven distribution of the magnetic material.

In order to obtain good dispersion of the magnetic material in the toner, it is essential to use magnetic particles with a bulk density of 0.35 g/cm" or more, preferably 0.5 g/cm" or more. It is the body.

In the present invention, the bulk density of a magnetic material refers to a value measured according to JIS (Japanese Industrial Standard) K-5101.

The magnetic material contained in the toner according to the present invention is 10,000
Under a magnetic field of 0e, the coercive force (He
), more preferably 80
It is 0e or less. In magnetic particles, the coercive force is dominated by magnetocrystalline anisotropy and shape anisotropy, and can be understood to indirectly define the surface shape. That is,
When a magnetic material becomes crystalline, its coercive force increases and the magnetic particles begin to have sharp edges on their surfaces.

When a toner containing magnetic particles having such edge portions on the surface is used in the present invention, local charges may concentrate on the edge portions, and the shape of the toner itself tends to become distorted. Since this may impede the slipperiness, fluidity, etc. of the toner, it is preferable for the magnetic material to have a low coercive force and a substantially curved surface.

However, the coercive force may show a value of 1000e or less even when the magnetic particles form an aggregate, so even in this case, the bulk density needs to be 0.35 g/cm'' or more.

Furthermore, the magnetic substance contained in the toner according to the present invention is 10
10e mu/g under a magnetic field of 0000e
Hereinafter, it is preferable to use magnetic particles having a residual magnetization (σr) of preferably 7 emu/g or less.

When the residual magnetization of the magnetic material is greater than 10 emu/g,
This is not preferable because the magnetic agglomeration of the magnetic particles becomes thick (thick) and tends to exist as aggregates in the toner, and uneven distribution of the magnetic particles causes non-uniformity of the toner as described above.

The magnetic properties of the magnetic material are, for example, V manufactured by Toei Kogyo Co., Ltd.
This refers to the value measured by SMP-1.

The magnetic toner according to the present invention has a triboelectric charge and is therefore substantially electrically insulating. Specifically, 3.0Kg/c
It is preferable that the magnetic material according to the present invention has a resistance value of 1014 Ω·cm or more when a voltage of 100 V is applied under a pressure of 100 V. 150 parts by weight (preferably 45 to 100 parts by weight)
(parts by weight). If it is less than 30 parts by weight, the conveyance of the magnetic toner on a toner carrier such as a sleeve will be insufficient. If it exceeds 150 parts by weight, the insulation properties and heat fixing properties of the magnetic toner will deteriorate.

The magnetic material according to the present invention is preferably produced by a wet method using ferrous sulfate as a raw material, and is magnetite or ferrite containing 0.1 to 10% by weight of a divalent metal compound such as manganese or zinc. Preferably, it is formed from.

It is preferable that the magnetic material contained in the toner of the present invention be subjected to a crushing treatment if necessary. Mechanical crusher equipped with high speed rotor for crushing,
A pressure dispersing machine equipped with a weighted roller for dispersing or crushing powder is exemplified.

When crushing aggregates of magnetic particles using a mechanical crusher, the impact force from the rotor is likely to be excessively applied to the primary particles of the magnetic particles (the primary particles themselves may be destroyed). Therefore, when a magnetic material that has been crushed by a mechanical crusher is used as a toner raw material, if there is a large amount of fine magnetic particles, the fine magnetic particles will be generated. The proportion exposed to the surface of the developer increases, and as a result, the abrasive effect of the developer itself is enhanced, and the characteristics originally sought are no longer met.

On the other hand, a pressure dispersing machine equipped with a weighted roller such as a fret mill is preferable in terms of efficiency in disintegrating magnetic particle aggregates and suppressing the production of fine powder magnetic particles.

As the metal complex monoazo dye having a hydrophilic group according to the present invention, a metal complex monoazo dye known as a charge control agent for negative toners can be used as appropriate.

As the monoazo dye, a metal complex type monoazo dye having a coupling product of a phenol or naphthol derivative as a ligand and having the following structural formula (I) or (II) is preferably used.

(Left below) The hydrophilic group referred to here refers to a polar atomic group that has a strong interaction with water. The main hydrophilic groups are -So, H, -
So, M, -COOM.

-NR, X, -COOH, -NHg, -CN.

-OH, -NHCONHl, -X, -No, etc. (where R: alkyl group, M: alkali metal or -
NH,,X: halogen). In the present invention, halogen (-X) is used as a hydrophilic group.

Carboxyl (-COOH), Hydroxyl (-OH)
, nitro (-Noff), sulfone (-SO,H)
, sulfonamino (-3o.

NH4) groups are preferably used.

Such a monoazo dye having a hydrophilic group preferably has a benzene nucleus or a naphthalene nucleus in the ligand, and preferably has a 0,0°-dioxyazo structure.

The above-mentioned hydrophilic group is preferably directly bonded to a monocyclic or polycyclic hydrocarbon group (eg, benzene nucleus, naphthalene nucleus) in the structural formula.

Furthermore, in order to fully exhibit the effect of adding the metal complex compound to the toner, the metal atoms in the metal complex must be Cr.
is preferable in order to improve the charging property of the toner,
In addition, the particle size is preferably smaller in order to improve dispersibility in the resin, and a specific value is a volume average particle diameter (dv) of 9.0.
The number average particle diameter (dn) is preferably 5.0 μm or less.

More specifically, a complex compound having the following structure is particularly preferably used as the metal complex compound.

(Left below) The amount of the metal complex compound mentioned above is 10 O of the binder resin.
0.5-10 for NNRIZ. O! The iXi part is preferred, and is 1.0 to 6. O! More preferably, the amount added is less than 2 parts, and the toner tends to lack the slipperiness and fluidity that are the objects of the present invention. Furthermore, if the amount of addition (2) exceeds the above range, the frictional charging power of the toner tends to decrease, perhaps because the opportunities for contact between the metal complex compounds increase and prevent them from charging each other.

The developer of the present invention contains silicone oil or fine powder treated with silicone oil, and preferably has a form in which the fine powder is dispersed on the surface of the developer.

Since the developer according to the present invention has the above-described structure, it is possible to further prevent adhesion to the surface of the developer carrier and film-like contamination, and to always form good images. That is, the developer according to the present invention is a developer that matches extremely well with the image forming apparatus according to the present invention and allows the image forming apparatus to be fully utilized, and the developer according to the present invention and the image forming apparatus are compatible. An image forming method that can provide good images has been established.

The present inventors believe that the reason for this is that the fine particles present on the surface of the developer serve as a lubricant between the developer and the device components, but it is particularly important to treat the fine particles with silicone oil or silicone face. It is presumed that this may also soften the impact of contact between fine particles and device members.

The particle size of the fine powder used in the present invention is 0.001 to 2μ
It is preferably in the range of 0.005 to 0.2μ, especially
0 The material of the fine powder used in the present invention is preferably an inorganic compound 0 For example, silicic acid, alumina, titanium oxide, etc.
Metal oxides of Group 3 and Group 4 are preferred.

Particularly preferred is silicic acid fine powder, and as silicic acid fine powder,
Both the so-called dry process or fumed silica produced by vapor phase oxidation of a silicon halide compound, and the so-called wet process silica produced from water glass etc. can be used; There are fewer silyl groups in Na, O, So, "-
It is preferable to use dry silica which does not leave any residue after production.

In addition, in the manufacturing process of dry silica, for example,
It is also possible to obtain a composite fine powder of silica and other metal oxides by using other metal halide compounds such as aluminum chloride or titanium chloride together with a silicon halide compound, and these are also included.

In the silicone oil treatment of fine powder used in the present invention, silicone oil is applied to the surface of the fine powder to completely cover the silanol groups and remove debris.
Moisture resistance is dramatically improved.

The silicone oil or silicone face solid content used in the present invention is generally represented by the following formula: R: C1-C3 alkyl group Ro: alkyl, halogen-modified alkyl.

Silicone oil modified group R'' such as phenyl, modified phenyl, etc.: C, to C3 alkyl group or alkoxy group For example, dimethyl silicone oil, alkyl modified silicone oil, α-methylstyrene modified silicone oil, chlorphenyl silicone oil, fluorine modified silicone In addition, the above-mentioned silicone oil preferably has a viscosity of approximately 50 to 1000 centistokes at 25°C.A silicone oil whose molecular weight is too low may generate volatile components when subjected to heat treatment, etc. Also, if the molecular weight is too high, the viscosity will be too high, making processing difficult.

Known techniques are used for the silicone oil treatment; for example, fine powder and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or silicone oil may be jetted onto the base fine powder. Also good. Alternatively, it may be produced by forming it into a festival shape, mixing it with the base fine powder, and then removing the solvent.

Further, it is more preferable that the fine powder used in the present invention is first treated with a silane coupling agent and then treated with silicone oil or silicone face.

In general, with silicone oil treatment alone, a large amount of silicone oil is needed to cover the surface of the fine powder, making it easy for fine powder aggregates to form during the treatment, and when applied to a developer, the fluidity of the developer may deteriorate. , it is necessary to be very careful about the silicone oil treatment process. Therefore, in order to remove aggregates of fine powder while maintaining good moisture resistance, it is better to treat the fine powder with a silane coupling agent and then with silicone oil to fully demonstrate the treatment effect of silicone oil. That's true.

The silane coupling agent used in the present invention is represented by the general formula % R: alkoxy group, or chlorine atom m: an integer of 1 to 3 n: an integer of 3 to 1, and is typically represented by dimethyl dichloride. Silane, trimethylchlorosilane, allyldimethylchlorosilane, hexamethyldisilazane, allyl phenyldichlorosilane, benzyldimethylchlorosilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinylchlorosilane , dimethylvinylchlorosilane, etc.

The above fine powder is treated with a silane coupling agent by a dry process in which the fine powder is made into a cloud shape by stirring or the like and reacted with a vaporized silane coupling agent, or by dispersing the fine powder in a solvent and dropping the silane coupling agent. The treatment can be carried out by a generally known method such as a wet reaction method.

The silane coupling agent is used for 100 parts by weight of fine powder.
It is preferable to use 1 to 50 parts by weight, more preferably 5 to 40 parts by weight.

The processing amount of silicone oil or silicone varnish solid content in the present invention is preferably 1 to 35 parts by weight, more preferably 2 to 30 parts by weight, based on 100 parts by weight of the fine powder. The reason for limiting the above processing amount is that if the silicone oil processing amount is too small, the result will be the same as silane coupling agent treatment alone, and the moisture resistance will not improve and the fine powder will absorb moisture under high humidity, resulting in high quality copies. In addition, if too much silicone oil is processed, the above-mentioned fine powder agglomerates are likely to form (or free silicone oil may be formed), so do not apply it to the developer. In this case, disadvantages arise such as the inability to improve fluidity.The applied amount of these treated fine powders to the developer is 0.01 to 20 parts by weight per 100 parts by weight of the developer (toner). More preferably, it is 0.1 to 3 parts by weight.

In addition to the above, the toner of the present invention may contain dispersed additives such as a colorant such as a pigment or a dye, and further additives such as a lubricant or a fixing aid, if necessary.

In particular, by appropriately selecting the release agent, etc., which are generally added to improve offset resistance, the toner of the present invention can be used without reducing the developing power or hindering the ease of charging. It was found that the slip properties, fluidity, etc., can be improved.

That is, low molecular weight polyalkylenes are suitable as the mold release agent used in the present invention, and in particular polyalkylenes with multiple peaks in molecular weight distribution, specifically those with at least two chromatograms in gel permeation chromatography. The molecular weight corresponding to the main maximum value is in the range of 2.000 to so, ooo, and has at least one other maximum value on the lower molecular weight side than the main maximum value. It's good to be there. Preferably 1/30-1/5 of the molecular weight of the main maximum value, more preferably 1/5
It is good to have another maximum value at a position of 20 to 1/10.

Further, the low molecular weight polyalkylene used in the present invention is preferably a propylene-ethylene copolymer, and more preferably, the ethylene unit is 1 to 10 fi% by weight of the low molecular weight polyalkylene.
Preferably, it is included.

It is presumed that by adopting the above configuration, dispersion in the toner is improved, and the uniform developability of the toner is further improved or not impaired.

The toner of the present invention can be manufactured by a conventional method. That is, fine magnetic powder is added to the binder resin described above.
After mixing the charge control agent or other additives and dispersing the mixture using, for example, a Henschel mixer, hot melt kneading is performed using a hot melt kneading device such as a twin screw extruder, and after cooling, the obtained lump is pulverized to form the desired mixture. The toner of the present invention is obtained by extracting toner particles having a particle size range by air classification.

[Example] The method of the present invention will be specifically described below based on Examples. However, this does not limit the embodiments of the present invention in any way. The numbers in the production examples and examples are parts by weight.

Synthesis Example 1 200 parts of cumene was placed in a reactor, and the temperature was raised to reflux temperature. To this were added 85 parts of styrene monomer, 10 parts of acrylic acid monomer and 8.5 parts of di-tert-butyl peroxide.
Part of the mixture was mixed. Furthermore, under cumene reflux (146°C to 156°C)
Solution polymerization was completed and the temperature was raised to remove cumene. 30 parts of the obtained styrene-acrylic acid copolymer was dissolved in the following monomer mixture to prepare a mixed solution.

It was made into a dispersion. The above suspension dispersion was added to a reactor containing 15 parts of water and purged with nitrogen, and suspension polymerization was carried out for 6 hours at a reaction temperature of 70 to 95°C. After completion of 8 reactions, it was filtered, dehydrated, dried, and copolymerized. A combined composition was obtained.

The composition includes a styrene-acrylic acid copolymer, a styrene-
The acrylic acid-n-butyl acrylate copolymer was uniformly mixed.

Further, the acid value of this copolymer was 25.0.

200 parts of cumene was placed in the main reactor and heated to reflux temperature. The following mixture was subjected to solution polymerization under refluxing of cumene, and after the reaction was completed, the temperature was raised to remove the polyvinyl alcohol moiety from the mixed solution.

Add 170 parts of water in which 0.1 part of compound was dissolved and suspend
The above styrene-maleic acid. 30 parts of -buty,...,-tester copolymer was dissolved in the following -414 substance mixture to form a mixture, and the same procedure as in Synthesis Example 1 was carried out to obtain styrene-n-butyl maleate half ester copolymer and styrene-acrylic acid. A composition of n-butyl-n-butyl maleate half ester copolymer was obtained.

The acid value of this copolymer was 20.6.

Synthesis example 3 200 parts of cumene was placed in a reactor and the temperature was raised to reflux temperature.

To this was added a mixture of 78 parts of styrene monomer, 15 parts of n-butyl acrylate monomer, 7 parts of n-butyl maleate half ester, 0.3 part of divinylbenzene, and 1.0 part of di-tert-butyl peroxide under refluxing of cumene. 4
The mixture was added dropwise over a period of time, and the polymerization reaction was further carried out for 4 hours. Thereafter, the solvent was removed by ordinary vacuum distillation to obtain a conjugate.

The acid value of this copolymer was 19.5.

Synthesis Example 3 was carried out in the same manner as in Synthesis Example 3, except that 82 parts of styrene monomer, 18 parts of n-butyl acrylate monomer, and 0 part of n-butyl maleate half ester were used.

The acid value of this copolymer was 0.4.

Production Example 1 The above mixture was melt-kneaded with a twin-screw extruder heated to 140°C, the cooled kneaded product was coarsely pulverized with a hammer mill, and the coarsely pulverized product was pulverized with a jet mill to obtain a finely pulverized product. The powder was further precisely classified and removed at the same time to remove ultrafine powder and coarse powder using a multi-division classifier using the Coanda effect (Elbowjet classifier manufactured by Nittetsu Kogyo Co., Ltd.) to obtain a magnetic toner (I) having an average particle size of 12 μm.

The above mixture was treated in the same manner as in Production Example 1 to obtain a magnetic toner (11) having an average particle size of 11.5 μm.

Manufacturing example 3 A magnetic toner (III) was obtained.

Production Example 4 A magnetic toner (rV) having an average particle size of 11 μm was obtained using the same ingredients as in Production Example 1.

Ethylene-propylene copolymer used in the above production examples■
Table 1 shows the molecular weights at the peak positions in the GPC chart of ~■.

Table 1: The above mixture was prepared in the same manner as in Production Example 1 to obtain an average of 12 μm C1
1 Silicic acid fine powder Aerosil #2 with a specific surface area of 200 m'/g
00 (manufactured by Nippon Aerosil Co., Ltd.) was treated with 20 parts of hexamethyldisilazane (HMDS), and then treated with 10 parts of dimethyl silicone oil KF-96100cS (manufactured by Shin-Etsu Chemical) diluted with a solvent. After drying, heat treatment was performed at 250°C to obtain fine silicic acid powder treated with hexamethyldisilazane and dimethyl silicone oil, and 0.6 part was externally added to 1100 parts of magnetic toner to obtain a developer. Ta.

This developer and a commercially available laser beam printer (L
B P-8II, manufactured by Canon) was modified, and the surface of the developer carrier was coated with a synthetic resin containing conductive graphite particles at a ratio of 1/1 to phenol resin (film thickness: 7 μm). Image output evaluation was performed using the changed version. Note that the developing bias is an AC bias Vpp of 1600 V.

The frequency was set to 1800Hz.

As a result, normal temperature (20℃/60%Rh), high temperature (32.5℃/85%Rh), low temperature and low humidity (15℃/1
Even in an environment of 0% Rh), it was possible to obtain a good image with no environmental dependence, uniform development, and no sleeve memory.

Furthermore, while replenishing the toner, an evaluation of image quality was performed on 5,000 sheets, and it was possible to obtain uniform and good images without any problems. Also, toner adhesion to the surface of the developer carrier,
And no scratches were observed.

The silicic acid fine powder of Example 1 was mixed with α-alumina (specific surface area: 10
A similar treatment was carried out to obtain a treated fine powder, and 0.8 parts of the powder was externally added to 11,100 parts of magnetic toner to obtain a developer, and images were produced.

As a result, compared to Example 1, 3000
Although the image density was slightly low after the first sheet, it was at a level without any problem, and as in Example 1, the image was uniform and good without sleeve memory.

No adhesion of developer or occurrence of scratches was observed on the surface of the developer carrier after 3000 images were printed.

The fine silicic acid powder of Example 1 was mixed with dimethyl silicone oil KF.
-9610 parts diluted with a solvent, subjected to IA treatment, dried and heat treated at approximately 280°C to obtain dimethyl silicone oil treated silica, which was externally added in an amount of 0.4 part to 100 parts of magnetic toner II+. A developer was obtained. When image printing was carried out in the same manner as in Example 1, it was possible to obtain uniform and good images without sleeve memory up to 4,000 sheets.

Further, although some developer was observed to adhere to the surface of the developer carrier, it was at a level that did not affect the image.

Comparative Example 1 Silicic acid fine powder Aerosil #1 with a specific surface area of 130 m2/g
30 (manufactured by Nippon Aerosil Co., Ltd.), 100 copies were added to HMDS20.
Obtain HMDS-treated silicic acid fine powder treated in
A developer was obtained by externally adding 0.9 parts to the rvt oo portion of the magnetic toner. Using this developer, we performed the same image output evaluation as in Example 1, and found that after several 10 sheets of image output,
Image unevenness has occurred. Furthermore, even though images were printed up to 200 images, the image unevenness did not recover. In addition, a large number of streaks were generated on the surface of the developer carrier, and several white streaks were generated on the image.

Fire Gohan 1 The surface of the developer carrier of Example 1 was coated with a synthetic resin containing conductive graphite particles and phenol resin at a ratio of 1:1.5 (film thickness: 6.5 mm). 5μm)
In Example 1, using the same developer as in Example 1 instead of
I created the same image.

As a result, it was possible to obtain uniform and good images without sleeve memory up to 5,000 sheets.

Further, no scratches or adhesion of developer were observed on the surface of the developer carrier.

[Effects of the Invention] As explained above, by using the developer and image forming method according to the configuration of the present invention, a cylindrical rotary developer can be used in a simplified developing device without sleeve memory. It is possible to uniformly support the carrier in a direction parallel to the rotation axis of the carrier. This allows you to obtain a uniform image,
Moreover, it has become possible to obtain a developer and an image forming method that do not damage the coat sleeve or cause the developer to stick.

[Brief explanation of the drawing]

FIGS. 1A to 1C are diagrams for explaining the outline of a sleeve memory, and FIG. 2 is a sectional view of the developing device of the present invention. 1... Electrostatic latent image carrier (photosensitive drum) 2... Developer carrier (sleeve) 3... Multipolar permanent magnet 4... Developer storage chamber 6... Doctor blade 10...・Coating

Claims (2)

[Claims] (1) Contains conductive fine particles on the surface of the developer carrier that contacts the developer in the developer storage chamber, carries it on its surface, and transports it to the development area formed between it and the electrostatic latent image carrier. A developer containing a toner used in a developing device having a coating layer formed thereon, the developer comprising: (1) a polymerizable monomer unit containing an acid group consisting of a carboxyl group or an acid anhydride thereof; A binder resin containing 2 to 30 parts by weight in 100 parts by weight of the binder resin and having an acid value of 1 to 70, magnetic particles having a bulk density of 0.35 g/cm^3 or more, and a hydrophilic group. A developer comprising: a toner containing at least a metal complex salt type monoazo dye; and (2) an inorganic fine powder treated with silicone oil or silicone varnish. (2) Contains conductive fine particles on the surface of the developer carrier that contacts the developer in the developer storage chamber, carries it on its surface, and transports it to the development area formed between it and the electrostatic latent image carrier. In an image forming method using a developing device having a coating layer formed thereon, the developer comprises (1) a polymerizable monomer unit containing an acid group consisting of a carboxyl group or an acid anhydride thereof, and 100 parts by weight of a binder resin. contains 2 to 30 parts by weight, and has an acid value of 1 to 30 parts by weight.
70, magnetic particles having a bulk density of 0.35 g/cm^3 or more, and a metal complex type monoazo dye having a hydrophilic group; (2) treated with silicone oil or silicone varnish; 1. An image forming method comprising: