JP3210201B2 - Image forming method and magnetic toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for developing an electrostatic latent image formed by a method such as electrophotography or electrostatic printing, and a magnetic toner for use in the image forming method. .

[0002]

2. Description of the Related Art An electrophotographic method is disclosed in U.S. Pat.
A number of methods are known as described in Japanese Patent Publication No. 7,691, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 43-24748, but generally, a photoconductive substance is used, An electric latent image is formed on the photoreceptor by various means, then the latent image is developed using toner, and if necessary, a toner image is transferred to a transfer material such as paper.
The toner is fixed by pressure, heat and pressure, or a solvent vapor to obtain a copy, and the remaining toner which has not been transferred onto the photoreceptor is cleaned by various methods, and the above steps are repeated.

As a developing method, a one-component developing method is preferably used from the viewpoint of miniaturization, weight reduction, and maintenance-free of the apparatus.

[0004] Among them, a toner carrier and an electrostatic latent image carrier are arranged at a certain gap, and a thin layer of magnetic toner which does not contact the latent image carrier is formed on the toner carrier. A jumping developing method (Japanese Patent Publication No. 58-3) in which an alternating electric field is applied between the carrier and the latent image carrier to perform development.
No. 2375) is preferably used.

This method increases the chance of contact between the sleeve and the toner by applying the magnetic toner on the sleeve in a very thin manner, enables sufficient triboelectric charging, supports the magnetic toner by a magnetic force, An excellent image can be obtained by relatively moving the toner to prevent the toner particles from agglomerating with each other and sufficiently rubbing with the sleeve.

Further, since the thin toner layer of the toner carrier is not in contact with the latent image carrier, even when an organic photoconductor which is inexpensive and easily mass-produced is used, its life is long and it can be adapted to high speed. Can be.

A developer carrier used in the dry developing method has been proposed in, for example, Japanese Patent Application Laid-Open No. Sho 57-66455. It is known that a metal or alloy compound such as aluminum, nickel, and stainless steel is formed into a cylindrical shape, and the surface thereof is treated to a predetermined surface roughness by means such as electrolysis, blasting, and sanding. I have.

While the above-described developer carrier is inexpensive and relatively stably provides a high-quality image, the use of a one-component type developer which is charged by the developer carrier is not sufficient. Although it is difficult to adjust the charge, and various measures have been taken with the developer, the problem relating to the non-uniformity of the charge has not been completely solved.

As disclosed in JP-A-61-180267, the surface of a developer carrying member is coated with a conductive film containing a texturing agent, or the developer carrying member is made of the same material as the film. It has been proposed to.

However, even in these methods,
It has not been sufficiently solved for a one-component magnetic developer.

The reason for this is that the developer contains a substance such as a magnetic substance having a relatively low resistance in the developer, and the charge easily escapes, the charge tends to be nonuniform, and the high hardness magnetic substance is contained in the developer. It contains such an inorganic substance, and it is difficult to stabilize the image quality due to accelerated wear of the coating.

The above phenomenon is described in Japanese Patent Application Laid-Open No. 52-119.
As shown in Japanese Patent No. 651, JP-A No. 651 is particularly remarkable in a production method in which a coating layer is formed with a liquid or paste-like paint.

In the case of a liquid or a paste, there is a period when the pigment can move inside the coating (touch dry period), and the surface of the developer carrying member tends to be smooth due to surface tension and compatibility of the material. Is due.

In JP-A-60-80876,
It has been proposed that the surface of the developer carrier is coated with a conductive film agent or that the developer carrier is made of the same material as the film agent.

However, even in these methods, the image quality is not sufficiently stabilized with respect to the number of endurable sheets. As the durability test proceeded, it was recognized that the image density rose (increased) or fell (decreased) and the image density was unstable.

It is considered that this is because the protruding state of the pigment having conductivity on the surface of the coating layer changes.

In the initial state of the developer carrier, the protrusion of the pigment is relatively small due to the surface tension of the material and the compatibility of the material. However, as the durability test proceeds, the surface layer of the developer carrier is scraped by the developer, It is considered that a proper surface is formed. On the other hand, it is recognized that the above phenomenon can be reduced by using a material having friability such as graphite as a pigment. This is considered to be because the surface state is quickly stabilized by the friability of the substance.

However, when graphite is added, the following problems occur.

(1) Since graphite is usually in the form of flakes, even a material having an average particle size of several μm has a width of several tens of μ in the direction of the major axis (break surface). ing. Even when the ratio between the conductive surface (pigment surface) and the insulating surface (resin surface) is stable when viewed macroscopically on the developer carrying ground surface, microscopically (developer size level) It is non-uniform, and the ability of the developer carrier to impart charge to the toner becomes non-uniform. As a result, the thickness of the toner coat layer locally changes, and the density changes.

(2) Since the surface of the broken surface is flat, the toner sticking phenomenon is likely to occur.

The above phenomenon is caused by the fact that the coating layer is formed as described in JP-A-52-11.
This is particularly noticeable in a production method in which a liquid or paste-like paint is used in the method described in Japanese Patent No. 9651.

In these methods, there is a period during which the pigment in the liquid or paste-like paint can move inside the coating (touch drying time), and the surface of the developer carrying member depends on the surface tension and the compatibility of the material. This is because the surface of the binder resin is likely to appear.

As for the fixing step, the most common method at present is a heat compression method using a heat roller. The heat-compression bonding method using a heat roller performs fixing by allowing the toner image surface of a sheet to be fixed to pass through the surface of a heat roller having a surface formed of a material having releasability with respect to the toner while pressing the surface under pressure. . In this method, since the surface of the heat roller and the toner image of the non-fixed sheet come into contact with each other under pressure, the thermal efficiency when fixing the toner image on the sheet to be fixed is extremely good, and the fixing can be performed quickly.
It is very effective in high-speed electrophotographic copying machines.

In recent years, such copying apparatuses have been strictly sought for smaller size, lighter weight, higher speed, lower energy, and higher reliability, and as a result, the performance required for the toner has also become higher. It is getting more advanced.

For example, in response to a demand for low energy, most of the power consumption is used for the heat source of the fixing device.
The heat compression bonding method using a heat roller is disadvantageous. To overcome this, it is necessary to lower the temperature of the heat roller as much as possible, and it is necessary to improve the melting characteristics of the toner.

A problem with the conventional low-energy toner that can be melted is that when toner on a transfer material such as paper comes into contact with the heat roller, the toner adheres to the surface of the heat roller and stains the image. Latitude narrows.

[0027] Toner fluidity decreases, and in extreme cases, blocking occurs.

Contamination of the toner carrier and the electrostatic latent image carrier.

The deterioration of the charging characteristics and the image caused by the above.

[0030] Efficiency is reduced during the production of toner.

Specifically, conventionally, for the purpose of preventing the toner from adhering to the surface of the fixing roller, a method of adding a wax such as low molecular weight polyethylene or polypropylene which sufficiently melts when heated in order to increase the releasability as a toner has also been used. Although this method is effective for preventing offset, it tends to increase the cohesiveness of the toner, destabilize the charging characteristics, and reduce the durability. Therefore, various attempts have been made to improve the binder resin as another method.

For example, a method is known in which the glass transition temperature (Tg) and the molecular weight of the binder resin in the toner are increased to improve the melt viscoelasticity of the toner. However, in such a method, when the offset phenomenon is improved, the fixing property becomes insufficient, and the fixing property at a low temperature required for high-speed development and energy saving, that is, the low-temperature fixing property is inferior. .

In general, in order to improve the low-temperature fixability of a toner, it is necessary to lower the viscosity of the toner at the time of melting to increase the contact area with the fixing base material. Is required to be low.

That is, since the low-temperature fixing property and the offset preventing property have contradictory aspects, it is very difficult to develop a toner that simultaneously satisfies these functions.

In order to solve this problem, for example, Japanese Patent Publication No. 51-233354 discloses a toner comprising a suitably crosslinked vinyl polymer by adding a crosslinking agent and a molecular weight modifier. Japanese Patent Application Laid-Open No. 6805 discloses a toner having a wide molecular weight distribution such that the ratio of the weight average molecular weight to the number average molecular weight using α, β unsaturated ethylenic monomer as a constituent unit is 3.5 to 4.0. Further, a blend-type toner or the like in which Tg, molecular weight, gel content, and the like of a vinyl polymer are combined has been proposed.

Certainly, the toner according to these proposals has a lower fixing temperature (the lowest temperature at which fixing is possible) and an offset temperature (a temperature at which offset starts to occur), compared to a toner made of a single resin having a narrow molecular weight distribution. Although the temperature range that can be fixed is widened, if sufficient anti-offset performance is given, the fixing temperature cannot be lowered sufficiently. There was the problem of becoming.

In place of these vinyl resins, there is also a toner obtained by crosslinking a polyester resin which is considered to be essentially superior to a vinyl resin in terms of low-temperature fixability, and further adding an offset preventing agent. JP-A-57-2085
No. 59 is proposed. This is excellent in both low-temperature fixability and offset prevention, but has a problem in productivity (pulverizability) as a toner.

Further, in JP-A-56-116043, a vinyl monomer is polymerized in the presence of a reactive polyester resin, and a polymer is formed through a crosslinking reaction, an addition reaction, and a grafting reaction in the polymerization process. Although a toner using a modified resin has been proposed and is improved in terms of pulverizability, the functions of the resins cannot be sufficiently utilized in terms of low-temperature fixability and offset prevention.

Further, a toner simply using a resin obtained by blending two types of vinyl resins (gelling degree of 80% or more and gelling degree of less than 10%) different from a polyester resin and a gel content is disclosed in Japanese Patent Publication No. 1-15063. Although this is proposed in the gazette, it has good low-temperature fixability, but is not yet sufficient in terms of anti-offset properties and pulverizability. Even if the ratio of the vinyl resin having a gelation degree of 80% or more is increased for the purpose of improving the offset resistance, the anti-offset property is improved, but the low-temperature fixability is significantly reduced. Gelation degree 1
Sufficient pulverizability cannot be satisfied only by containing less than 0% of a vinyl resin.

On the other hand, for the physical properties required for the toner as described above, crosslinking is carried out by reacting a polymer having a carboxylic acid with a metal compound in a binder resin (Japanese Patent Application Laid-Open No. 178249, 57-
No. 178250), or a polyvalent metal compound is reacted with a binder having a vinyl resin monomer and a more specific monoester compound as essential constitutional units, and crosslinked via a metal (Japanese Unexamined Patent Publication No. 61-1986). No. 110155, 61-1
No. 10156).

Further, JP-A-63-214760, JP-A-63-217362, and JP-A-63-21736.
In JP-A Nos. 3 and 63-217364, a carboxylic acid group having a molecular weight distribution divided into two groups, a low molecular weight and a high molecular weight, is reacted with a polyvalent metal ion to crosslink ( A dispersion of a metal compound is added to a solution obtained by solution polymerization, and the mixture is heated and reacted), but in any method, the reaction between the binder and the metal compound or the addition of the metal compound to the binder is carried out. The dispersion of the metal compound is not sufficient, and the physical properties required for the toner, particularly the fixing property and the offset resistance, have not yet been satisfied. In addition, since it is necessary to mix a large amount of the metal compound with the binder resin, the compounded metal compound exhibits a catalytic action on the binder resin depending on the condition, and the binder resin is easily gelled. It is difficult to determine the manufacturing conditions for obtaining the desired toner by blending, and for example, even if the manufacturing conditions can be determined, there is a problem that reproducibility is hardly obtained.

Further, in the adjustment of the acid amount in these proposals, the charging characteristics (rise), environmental characteristics (leaving characteristics under high humidity), and image characteristics (fog and density characteristics) of the toner are still insufficient.

Further, JP-A-2-168264, JP-A-2-23569, JP-A-5-173363,
In JP-A-5-173366 and JP-A-5-241371, the molecular weight, the mixing ratio, the acid value and the ratio of the low molecular weight component and the high molecular weight component in the binder resin are controlled, and the fixing property, non-offset property, image Properties and blocking resistance,
Although a binder composition for toner and a toner having improved charging start-up characteristics and the like have been proposed, their degree of perfection is still low.

In particular, in the adjustment of the acid value in the above publication, poor dispersibility of a coloring agent such as magnetic iron oxide, a charge control agent (charge control agent), and other additives occurs, and a developer or carrier such as a carrier or a sleeve is loaded. Image deterioration such as fog and density reduction due to contamination on the body surface occurs.

Further, the fixing at a lower temperature is insufficient.

In Japanese Patent Application Laid-Open No. 62-9256,
A binder composition for a toner in which two kinds of vinyl resins having different molecular weights and resin acid values are blended is disclosed. However, when using such a binder resin,
In order to improve the compatibility and dispersibility of the toner components, kneading conditions must be strengthened, and the resin of the binder is affected by cutting of molecules and the like, and exhibits desired performance such as offset resistance. It will be difficult to do. If kneading is performed to the extent that molecular breakage does not occur, poor dispersion of other additives will occur immediately, promoting contamination of the surface of the developer carrier such as carriers and sleeves, and fogging and scattering of developability. Cause serious problems. In particular, when a polymer having a weight average molecular weight of 1,000,000 or more is used, these phenomena become apparent.

Incidentally, JP-A-3-72505 discloses a vinyl-based toner binder having a molecular weight of 300,000 or more using a polyfunctional initiator. Although satisfactory, in addition to the above-described problems, the performance of the developer is deteriorated when left at high temperatures. Although the cause of this phenomenon is not clear, according to our investigation, only the molecular cleavage of the binder resin was promoted during the formation of the toner, so that the proportion of the resin component having a sufficient molecular weight in the toner composition was reduced. It is estimated that it became lower and became weaker to thermal shock.

Further, the various properties required for the above-mentioned toners are often reciprocal to each other, and it is more and more desirable in recent years to satisfy both of them with high performance. Research has been conducted on comprehensive responses that include characteristics, but there is still not enough.

In recent years, with the demand for higher speed of the apparatus, the toner is required to have further low-temperature fixing property, toughness of the toner which can be cut off at high speed development, and charging stability which can withstand long-term durability. I have.

However, it is difficult to achieve both the low-temperature fixability described above and the toughness of the toner at the same time, and at present there is no satisfactory structure in the above-mentioned prior art.

In the magnetic toner used for jumping development, a considerable amount of a fine powdered magnetic material is mixed and dispersed, and a part of the magnetic material is exposed on the surface of the toner particles. Affects the fluidity and triboelectricity of the magnetic toner, and as a result, the development characteristics of the magnetic toner,
There is an unstable factor that causes fluctuation or deterioration of various characteristics required for magnetic toner such as durability.

More specifically, in a conventional jumping development method using a magnetic toner containing a magnetic substance, if a long-term repeated development process (for example, copying) is continued, the developer containing the magnetic toner is removed. Liquidity worsens,
Normal frictional electrification cannot be obtained, the electrification tends to be non-uniform, and fog development tends to occur in a low-temperature and low-humidity environment, which tends to be a major problem on toner images. Also,
When the adhesiveness between the binder resin constituting the magnetic toner particles and the magnetic material is weak, the magnetic material tends to be removed from the surface of the magnetic toner by a repetitive development process, which has a negative effect such as a decrease in toner image density. is there.

When the dispersion of the magnetic substance in the magnetic toner particles is not uniform, small magnetic toner particles containing a large amount of the magnetic substance accumulate on the sleeve, resulting in a decrease in image density and a reduction in sleeve ghost. In some cases, the occurrence of so-called shading unevenness is observed.

Therefore, in order to make use of the excellent characteristics of each of the toner constituent components, it is necessary to select a material having good compatibility and physical mixing of each component in the toner design.
Further, it is required to find an image forming system that brings out the excellent characteristics of the toner and an appropriate image forming condition.

[0055]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming method and a magnetic toner which greatly improve the problems of the prior art.

That is, an object of the present invention is to provide an image forming method and a magnetic toner capable of obtaining a stable toner charging property over a long period of time.

It is a further object of the present invention to provide an image forming method and a magnetic toner in which the temperature and humidity are less affected by the environment and stable toner charging is obtained.

It is a further object of the present invention to provide an image forming method and a magnetic toner with less contamination of the developer carrying member.

It is a further object of the present invention to provide an image forming method and a magnetic toner which improve the fixing property and the anti-offset property and realize a high quality image.

[0060]

According to the present invention, a layer of magnetic toner is formed on a developer carrier which is arranged with a gap from the electrostatic latent image carrier, and the layer is formed on the developer carrier. An image forming method comprising a step of developing an electrostatic latent image on an electrostatic latent image carrier with the magnetic toner while applying an alternating current, wherein the developer carrier has at least a substrate and a coating layer, The surface is coated with the coating layer, the coating layer comprising: (i) a solid lubricant or a conductive agent, or a mixture of a solid lubricant and a conductive agent; The magnetic toner is formed of a coating material containing 3 to 30 μm spherical particles and (iii) a binder resin, and the magnetic toner is formed of a composition containing at least a vinyl resin, a magnetic material, and a charge control agent. And the polymer component in the magnetic toner is 1 mgKOH / g or more. Has an acid value, the polymer component in the magnetic toner, a) containing substantially no THF-insoluble matter, b) in the GPC chromatogram of the THF-soluble matter of the polymer components, the molecular weight 3 × 10 ^A main peak in a region of ^{3 to} 3 × 10 ⁴ and a subpeak or shoulder in a region of a molecular weight of 1 × 10 ^{5 to} 3 × 10 ⁶ c) a low molecular weight polymer component (in the GPC chromatogram, in 5 × 10 component of less than ⁴ area) acid value of (a _VL) and high molecular weight polymer component (GPC chromatogram, the molecular weight 5 × 10 ⁴ or more components of the regions) the acid value of (a _VH) and the following The present invention relates to an image forming method characterized by satisfying a relation A _VL > A _VH . Further, the present invention provides a method for forming a layer of magnetic toner on a developer carrying member arranged with a gap from the electrostatic latent image carrying member, and applying the magnetic current to the developer carrying member while applying an alternating current to the developer carrying member. An image forming method comprising a step of developing an electrostatic latent image on an electrostatic latent image carrier with a toner, wherein the developer carrier has at least a substrate and a coating layer, and the surface of the substrate is coated with the coating layer. The coating layer comprises: (i) a solid lubricant or a conductive agent, or a mixture of a solid lubricant and a conductive agent;
i) spherical particles having a number average particle diameter of 0.3 to 30 μm;
i) In a magnetic toner used in an image forming method formed by a coating agent containing a binder resin, the magnetic toner is formed of a composition containing at least a vinyl resin, a magnetic substance, and a charge control agent. Wherein the polymer component in the magnetic toner has an acid value of 1 mg KOH / g or more, and the polymer component in the magnetic toner is: a) substantially free of THF-insoluble components; b) polymer In the GPC chromatogram of the THF soluble component of the component, a main peak is present in a region of a molecular weight of 3 × 10 ^{3 to} 3 × 10 ⁴ , and a sub-peak or a shoulder is present in a region of a molecular weight of 1 × 10 ^{5 to} 3 × 10 ^6. C) the acid value (A _VL ) of the low molecular weight polymer component (the component in the region having a molecular weight of less than 5 × 10 ⁴ in the GPC chromatogram) and the high molecular weight polymer component (the molecular weight of 5 × 10 ⁴ in the GPC chromatogram); A magnetic toner characterized in that the acid value (A _VH ) of the ^four or more regions satisfies the following relationship: A _VL > A _VH .

According to the present invention, the polymer in the magnetic toner can be used in a long-term durability test in a high-temperature, high-humidity (about 35 ° C./90%) environment in which a general toner easily causes contamination of the developer carrying member. By using a toner having an acid value of 1 mgKOH / g or more (more preferably 2 mgKOH / g or more) as a component, developer carrier contamination is reduced. In addition, even under the above-mentioned severe conditions where the charge amount of the toner is apt to drop, the use of the developer carrier stabilizes the charge applying force and makes the charge amount of the toner uniform and a desired value.

That is, according to the present invention, by adopting the above constitution, the developer carrying member is prevented from being contaminated while improving the fixing property and the anti-offset property, and the charge imparting property to the toner, the toner conveying property and the abrasion resistance are improved. To achieve a synergistic effect.

Further, according to the present invention, the polymer component of the magnetic toner is a) substantially free of a THF-insoluble component, and b) the GPC chromatogram of the THF-soluble component of the polymer component has a molecular weight of 3 × 10 ^3. A main peak in the region of ３3 × 10 ⁴ and a subpeak or shoulder in the region of 1 × 10 ^{5 to} 3 × 10 ⁶ , c) a low molecular weight polymer component (in the GPC chromatogram, a molecular weight of 5 × 10 in acid value (a _VL) and high molecular weight polymer component (GPC chromatogram of components of less than ⁴ area), molecular weight 5 × 10 ⁴ or more components of the regions) the acid value of (a _VH) and satisfies the following relationship It is preferable that A _VL > A _VH be satisfied.

Further, according to the present invention, the low molecular weight polymer component has an acid value (A _VL ) of 21 to 35 mg KOH / g, and the high molecular weight polymer component has an acid value (A _VH ) of 0.5 to 11 mK.
gKOH / g, and the difference (A _VL −A _VH ) is 1
Preferably it is 0 to 27 mgKOH / g.

Further, in the present invention, the vinyl resin contains a vinyl low molecular weight polymer and a vinyl high molecular weight polymer, and the glass transition point (Tg) of the vinyl resin is 5 or less.
0-70 are ° C., and the glass transition point of the vinyl-based low molecular weight polymer (Tg _L) and the glass transition point of the vinyl-based high molecular weight polymer (Tg _H) and satisfies the following relationship Tg _L ≧ Tg _H -5 Is preferably satisfied.

Further, according to the present invention, the vinyl resin contains a vinyl low molecular weight polymer and a vinyl high molecular weight polymer, and the glass transition point (Tg) of the vinyl resin is 5 or less.
Is 5 to 65 ° C., and the glass transition point of the vinyl-based low molecular weight polymer (Tg _L) and the glass transition point of the vinyl-based high molecular weight polymer (Tg _H) and satisfies the following relationship Tg _L ≧ Tg _H Is preferred.

Further, in the present invention, the polymer component in the magnetic toner preferably satisfies the following relationship.

[0068]

[Outside 4]

Further, in the present invention, it is preferable that both the vinyl-based low molecular weight polymer and the vinyl-based high molecular weight polymer contain at least 65 parts by weight of a styrene monomer component unit.

Further, in the present invention, it is preferable that the vinyl high molecular weight polymer component is a polymer obtained by polymerization using a polyfunctional polymerization initiator.

Further, in the present invention, the vinyl high molecular weight polymer is preferably a polymer obtained by polymerizing at least a polyfunctional polymerization initiator and a monofunctional polymerization initiator in combination.

Further, according to the present invention, a GPC chromatogram measured by a THF-soluble component of the polymer component in the magnetic toner contains 3% or more of a polymer component having a molecular weight of 1,000,000 or more. preferable.

Further, in the present invention, the solid lubricant is preferably graphite.

Further, in the present invention, the conductive agent is preferably carbon black.

In the present invention, the spherical particles are preferably a methyl methacrylate resin (PMMA).

The developer carrier used in the present invention is used as a developing sleeve in a developing device. The developer carrier used in the present invention has a substrate such as cylindrical aluminum and a coating layer covering the surface of the substrate. The coating layer comprises 0.3 g of a solid lubricant, a conductive agent or a mixture of a solid lubricant and a conductive agent.
It contains at least a spherical substance having a number average particle size of ３０30 μm and a binder resin.

The developer carrier will be described. In FIG. 1, the development carrier 1 has a base 5 and a coating layer 6. The coating layer 6 of the development carrier is formed of the spherical particles 2, the binder resin 3, and the solid lubricant 4.

The solid lubricant used in the present invention is preferably graphite.

The conductive agent used in the present invention is preferably carbon black.

The spherical particles used in the present invention have a particle size of 0.3 to 0.3.
It has a number average particle size of 30μ.

The spherical particles are added to prevent, for example, the broken surface of graphite from becoming smooth. In particular, even when the coating layer of the developer carrying member is worn, a uniform surface is obtained. It is added to maintain the roughness. If the number average particle diameter of the spherical particles is less than 0.3 μm, there is no effect of surface roughness, and if the number average particle diameter exceeds 30 μm, the spherical particles protrude from the coating, and undesired development tends to occur only at that portion, which is not preferable. In the present invention, the term "spherical" means that the ratio of the major axis / minor axis of the particles is 1.0 to 1.5 (preferably 1.0 to 1.0.
2) is preferred. Particularly, true spherical particles are preferable.

Although the reason for the charging polarity of the spherical particles is not clear at present, a positively charging substance is preferable from the viewpoint of image density. Examples of the positively charged substance include resin compounds such as phenol resin, methyl methacrylate resin (PMMA), styrene-butadiene copolymer, and nitrogen-containing resin; and metal oxides such as alumina and zinc oxide. Methacrylate resins (PMMA) are preferred.

The positive chargeability is measured by a usual charge measuring method.

For example, the determination is made by mixing the spherical particles and a metal powder such as iron powder, and measuring the triboelectric charge of the spherical particles by a blow-off method.

Examples of the binder resin used for the coating layer on the developer carrier of the present invention include resins such as phenolic resins, epoxy resins and polycarbonate resins. Generally, a resin that imparts triboelectric charge to the toner in a positive polarity can be preferably used as the binder resin.

Among them, the thermosetting resin is more preferable in terms of production and durability. A phenol resin is most preferably used in view of the charging stability of the toner. The phenolic resin includes a pure phenolic resin produced from phenol and formaldehyde, and a modified phenolic resin obtained by combining an ester gum and a pure phenolic resin, and any of them can be used. Phenol resins are preferably used because they form a dense three-dimensional crosslinked structure by a thermosetting reaction, and can form a coating film that is very hard compared to other thermosetting resins (polyurethane, polyamide, etc.).

As the base of the developer carrier used in the present invention, metals and alloy compounds can be preferably used. In addition, non-metallic materials can be used.

However, in the structure of the present invention, since the developer carrying member (developing sleeve) is used as an electrode, it is necessary to provide a structure in which a current can be supplied when a nonmetallic substance, for example, a plastic molded product is used. For example, a metal is adsorbed on the surface of the developer carrying member by vapor deposition, or a conductive resin is used.

As the graphite used in the present invention, any of natural products and artificial products can be used.

As described above, the particle size of graphite is scale-like and cannot be specified unconditionally. As will be described later, it is difficult to indicate the range of the particle size of graphite due to a change in shape when dispersed by a stirring means such as a sand mill. It is preferable that the width in the plane direction is 100 μm or less.

As the measuring method, a method of directly observing a sample with a microscope is the most preferable method. As a simple method, there is a method in which measurement is performed with a usual particle size distribution meter (electric resistance type, sedimentation type, centrifugal type, laser scattering type, etc.) to obtain the maximum value.

The degree of graphitization of graphite is 60%
It is preferable that this is the case. Graphitization is a characteristic that affects the susceptibility to breakage of the crevice.
This is because the characteristics are considered to affect the difference from the durability state.

There are various methods for measuring the degree of crystallinity, but evaluation by X-ray diffraction is common and reproducibility is good.

As the carbon black used in the present invention, any of a furnace type and a channel type can be used. Among them, a substance having a low resistance is preferable in consideration of the characteristics of the film, and a carbon black having a resistance value of 0.5 Ω · cm or less under a pressure of 120 kg / cm ^{2 is} particularly preferable.

The amount W of carbon black to be added is expressed by the formula W = [{100 / (carbon black oil absorption)} × 10 with respect to 100 parts by weight of the binder resin.
0] × a.

[However, the carbon black oil absorption was measured for sample 1
Oil absorption of dibutyl phthalate per 100 g [cc / 1
00g] (ASTM No. D-2414-79), and the coefficient -a indicates 0.3 to 3. It is also possible to use several types of carbon black in combination, and in that case, the oil absorption is determined by actually measuring the mixture.

If the coefficient -a is less than 0.3, the effect of adding carbon black is not recognized, and if the coefficient -a exceeds 3, the coating hardness is undesirably reduced.

The addition amount of carbon black is more preferably such that the coefficient -a satisfies 0.5 to 2.

Next, a method for producing the developer carrier of the present invention will be described.

The coating agent used in the present invention is a solvent soluble in a binder resin, for example, a raw material of the coating agent so as to have a solid content of 5 to 50 wt% in an alcoholic solvent such as methanol or propyl alcohol for a phenol resin. And the pigment content is dispersed with a stirrer such as a sand mill, a ball mill, and an attritor to obtain a stock solution of a coating agent. A solvent is added to this coating agent stock solution to adjust to a solid content suitable for the production method to obtain a coating solution. This coating solution is applied on a developer carrier base and dried by touch, and then the coating layer is cured by heating or exposure to produce a developer carrier. As a coating method, a spray method, a dipping method, a roller coating method, a bar coating method, and an electrostatic coating method are used.

Next, the composition ratio of each component used in the present invention will be described. The following are particularly preferred ranges.

In the present invention, a particularly preferable result is obtained when the weight ratio of (graphite) / (binder resin) is in the range of 2/1 to 1/3. When the ratio is more than 2/1, a decrease in the film strength is observed, and when the ratio is less than 1/3, there is a high possibility that an illegal coating of the developer due to the influence of the binder resin occurs.

In the present invention, a particularly preferable result is obtained when the addition amount of the spherical particles is in the range of 1 to 20% by weight based on the weight of the binder resin. If it is less than 1%, the effect of adding the spherical particles is small, and if it exceeds 20%, the developing characteristics may be adversely affected.

In the present invention, the following additional substances may be added to the coating. A conductive substance may be added to adjust the resistance of the coating. As the conductive material, conductive carbon such as acetylene black and oil black; iron,
Metal powders such as lead and tin; and metal oxides such as tin oxide and antimony oxide. The amount of the additive can be used in the range of the additive substance / binder resin ratio of 12/1 to 1/3.

In order to further stabilize the charge of the toner, a charge control agent used for the toner may be added to the film. For example, nigrosine, a quaternary ammonium salt, a boric acid compound, and a phosphoric acid compound can be mentioned. In any case, by adding the spherical particles having a particle diameter of 0.3 to 30 .mu.m in the present invention, a stable developer-carrying member surface can be maintained.

The surface roughness of the developer-carrying member in the present invention is in the range of 0.2 to 5.0 (preferably 0.3 to 3) μ in terms of area average value (hereinafter referred to as Ra), Of the surface roughness (after endurance / initial) according to 0.5 to 2.
It is in the range of 0. If the surface roughness is less than 0.2 μm, the carrying capacity is reduced, which is not preferable. If it exceeds 5.0 μm, the developer coating layer becomes thick, and scattering and illegal development become unfavorable. The rate of change of the roughness is measured to confirm that the change in the surface roughness due to the durability achieved by the present invention is small.

On the surface of the developer carrying member, the relationship between the average pitch of roughness (Sm), which is the average interval of the irregularities on the surface of the coating film, and the average particle size (d) of the toner of the developer is Sm / d = 1. / 10 to 10, preferably 1/5 to 5, and the surface roughness (Ra) of the coating is preferably 0.3 to 3 μm, and more preferably 0.5 to 3 μm.

Length direction (Sm value) and height direction (Ra value)
Were used as representative values of the surface state. Here, when the Sm / d value is smaller than 1/10, the roughening effect does not appear. When the Sm / d value is more than 10, the surface becomes close to a smooth surface with respect to the toner size.

In the present invention, the center line average roughness (Ra)
Is measured based on JIS surface roughness (BO601) using a surface roughness measuring device (Surfcoder SE-30H, Kosaka Laboratory Co., Ltd.). Specifically, the center line average roughness (Ra) is obtained by extracting a portion having a measured length of 12.5 mm from the roughness curve in the direction of the center line, setting the center line of the extracted portion to the X axis and the direction of the vertical magnification. Is the Y axis, and the roughness curve is y = f
When expressed by (x), the value obtained by the following equation is expressed in micrometers (μm).

[0110]

[Outside 3]

In the present invention, the average interval (S
m) is Sm = L / n (where L is a reference length,
2.5 mm, and n indicates the number of peaks). As shown in the figure, the peak number n is provided with two peak count levels (± 0.21 μm) parallel to the center line of the roughness curve, and between the two points where the curve crosses the lower peak count level and the upper point, When the point where the curve intersects with the peak count level is present one or more times, it is regarded as one peak, and the number n of peaks is obtained between the reference lengths (2.5 mm).

In order to promote the release of the developer from the surface of the developer carrier, a substance having a low surface energy may be added.

For example, fluorine compounds, boron nitride, graphite and the like can be mentioned.

In the present invention, the polymer component constituting the toner particles contains substantially no THF-insoluble components. Specifically, the content is 5% by weight or less, preferably 3% by weight or less based on the polymer component.

The THF-insoluble content in the present invention means the weight ratio of the polymer component (substantially crosslinked polymer) insoluble in the THF solvent in the polymer component in the toner.
It can be used as a parameter indicating the degree of crosslinking of the polymer component containing the crosslinking component. The THF-insoluble matter is defined by a value measured as follows.

That is, 0.5 to 1.0 g of a toner sample was weighed (w ₁ g), and a cylindrical filter paper (No.
86R), subjected to a Soxhlet extractor, extracted with 100 to 200 ml of THF as a solvent for 6 hours, and evaporated the soluble components extracted by the solvent.
After vacuum drying at 100 ° C. for several hours, the amount of the THF-soluble resin component is weighed (w ₂ g). The weight of a component other than the resin component such as a magnetic substance or a pigment in the toner is defined as (w ₃ g). TH
The F-insoluble content is obtained from the following equation.

THF insoluble matter (%) = [｛(w ₁ − (w ₃
+ W ₂ )｝ / (w ₁ -w ₃ )] × 100

When the content of the THF-insoluble component exceeds 5% by weight, not only the fixing property is deteriorated, but also a problem occurs in matching with the heat fixing device used in the embodiment of the present invention.

TH of polymer component in magnetic toner of the present invention
The chromatogram of GPC measured by F-soluble matter is
Molecular weight 3 × 10 ^{3 to} 3 × 10 ⁴ (more preferably 5 × 10 ³
10 ^{3 to} 2 × 10 ⁴ ), and has a molecular weight of 1 × 10 ^{5 to} 3 × 10 ⁶ (more preferably,
It has a sub-peak or shoulder in the region of 5 × 10 ⁵ to 1 × 10 ⁶ ). In particular, when a main peak has a molecular weight of 3 × 10 ⁴ or more, scratches are likely to occur on a sleeve or a drum in a long-term durability test.

Further, in the chromatogram of the GPC, a polymer component having a molecular weight of 1,000,000 or more was found to have an area ratio of 3 to 10%.
Preferably, it is present at 10% or more. The presence of 3 to 10% of a THF-soluble component having a molecular weight of 1,000,000 or more improves the offset resistance without inhibiting low-temperature fixing and at the same time improves the storage stability of the developer under high-temperature storage. Can also be increased.

In the present invention, the molecular weight distribution of the polymer component in the magnetic toner is measured by GPC (gel permeation chromatography) under the following conditions.

<Conditions for GPC Measurement of Toner Composition and Resin> Apparatus: GPC-150C (manufactured by Waters) Column: KF801-7 (manufactured by Shodex Co.) Temperature: 40 ° C. Solvent: THF (tetrahydrofuran) Flow rate: 1.0 ml / min. Sample: 0.1 m of a sample having a concentration of 0.05 to 0.6% by weight
l injection

The polymer component according to the present invention comprises an acid value (A _VL ) of a low molecular weight polymer component (a component having a molecular weight of less than 5 × 10 ⁴ in a GPC chromatogram) and a high molecular weight polymer component (A _VL ). In the GPC chromatogram, the acid value (A _VH ) of the component having a molecular weight of 5 × 10 ⁴ or more satisfies the following relationship: A _VL > A _VH , and more preferably the low molecular weight polymer component ( In the GPC chromatogram, the acid value (A _VL ) of the component having a molecular weight of less than 5 × 10 ⁴ ) is 2
The acid value (A _VH ) of the high-molecular-weight polymer component (the component having a molecular weight of 5 × 10 ⁴ or more in the GPC chromatogram) is 0.5 to 11 mgKOH / g.
OH / g and the difference (A _VL −A _VH ) is 10 to
27 mgKOH / g.

The present inventors have conducted intensive studies and as a result, it has been found that, in a polymer component composed of a low molecular weight polymer component and a high molecular weight polymer component, each of the polymer components has the above-mentioned acid value and has a low-temperature fixing property. It has been found that it is most effective for improving the offset resistance and the developing property.

The low-temperature fixability is determined by the Tg of the low molecular weight polymer component.
And the molecular weight distribution is dominant, but the acid component is contained in this component, and furthermore, the acid value is higher than the acid value of the high molecular weight polymer component by 1%.
By increasing it by 0 mgKOH / g or more, the same Tg,
It has been found that the viscosity can be made lower than that of a resin composition having an acid value having the same molecular weight distribution outside the above range.

This is because the acid value of the high molecular weight polymer component is set at least 10 mg KOH / g lower than the acid value of the low molecular weight polymer component (acid value 0.5 to 11 mg KOH / g), whereby the low molecular weight polymer component is obtained. It is considered that the entanglement of the molecular chains of the high molecular weight component and the high molecular weight component is suppressed to some extent, so that the viscosity is reduced on the low temperature side and the elasticity is maintained on the high temperature side. This also leads to low-temperature fixing and improvement in developing characteristics.

On the other hand, the difference in the acid value (A _VL −A _VH ) is 27
If it exceeds mgKOH / g, the mixing property between the low-molecular-weight polymer component and the high-molecular-weight polymer component becomes defective, and the durability offset property and the developability deteriorate.

Further, the acid value of the low molecular weight polymer component is 21
It has been clarified that the rising property of charging becomes better at mgKOH / g or more.

On the other hand, the acid value of the low molecular weight polymer component is 35 m
If it exceeds gKOH / g, the environmental properties, especially the developability under high humidity, will be impaired.

The acid value of the high molecular weight polymer component is 0.5
If it is less than 1, the low molecular weight polymer component (acid value 21 to 35)
mgKOH / g), resulting in poor developability,
In particular, fog characteristics deteriorate.

[0131] Further, the polymer component in the magnetic toner of the present invention, in relation to the low molecular weight polymer component and a high molecular weight polymer component with respect to the mixing _{ratio, W L: W H = 50} : 50~90: 10 must be satisfied. The reason is that if the ratio of the low molecular weight polymer component to the high molecular weight polymer component is out of this range, the fixability and the anti-offset property become inadequate. That is, if the low molecular weight polymer component is less than 50% by weight, the fixing property is reduced, while if the high molecular weight polymer component is less than 10% by weight, the high temperature offset resistance is reduced.

Further, the relationship between the mixing amount and the acid value is as follows.

[0133]

[Outside 4] Is preferably satisfied. The reason is that the mixing amount of the low molecular weight polymer component and the high molecular weight polymer component and their respective acid values do not satisfy the relationship of the above formula, that is,

[0134]

[Outside 5] When the acid value of the low-molecular-weight polymer component in the entire resin is lower than four times the acid value of the high-molecular resin, the mixing property between the low-molecular-weight polymer component and the high-molecular-weight polymer component increases,
This is because the low viscosity on the low temperature side and the high elasticity on the high temperature side cannot be emphasized more.

In addition,

[0136]

[Outside 6] Is less than 11, the rising characteristics of charging are deteriorated. On the other hand, when it is more than 30, the phenomena under high humidity is reduced.

In the present invention, the acid value (JIS acid value) of the low molecular weight polymer component and the high molecular weight polymer component is determined by the following method.

<Separation of each component> [Apparatus configuration] LC-908 (manufactured by Nippon Kagaku Kogyo Co., Ltd.) JRS-86 (company; repeat injector) JAR-2 (company; autosampler) FC-201 (Gilson; Hula cushion collector) [Column configuration] JAIGEL-1H to 5H (20φ × 600 mm: preparative column) [Measurement conditions] Temperature: 40 ° C. Solvent: THF Flow rate: 5 ml / min. Detector: The RI sample is preliminarily separated from additives other than the polymer component. As a preparative method, an elution time at which the molecular weight becomes 5 × 10 ⁴ is measured in advance, and before and after the elution time, a low molecular polymer component and a high molecular polymer component are separated. The solvent is removed from the sampled sample to obtain a sample for acid value measurement.

<Measurement of Acid Value (JIS Acid Value)> 1) A crushed sample of 0.1 to 0.2 g is precisely weighed, and its weight is defined as W (g). 2) The sample is placed in a 20 cc Erlenmeyer flask, and 10 cc of a mixed solution of toluene / ethanol (2: 1) is added and dissolved. 3) Add a few drops of phenolphthalein alcohol solution as indicator. 4) Using an alcohol solution of 0.1 N KOH, titrate the solution in the flask with a burette.

At this time, the amount of the KOH solution used was S (ml).
And At the same time, a blank test is performed, and the amount of the KOH solution at this time is defined as B (ml). 5) Calculate the acid value by the following equation.

[0141]

[Outside 7] The measurement of the total acid value in the present invention is performed as follows.

<Measurement of Total Acid Value> 1) A sample is used after removing additives other than the polymer component in advance. Approximately 2 g of a crushed sample is precisely weighed, and the weight is
(G). 2) The sample is placed in a 200 cc Erlenmeyer flask, and 30 cc of 1,4-dioxane, 10 cc of pyridine and 20 mg of 4-dimethylaminopyridine are added and dissolved for 1 hour. 3) Add 3.5 cc of ion-exchanged water and reflux for 4 hours. Then cool. 4) Add a few drops of phenolphthalein alcohol solution as indicator. 5) Titrate the solution in the flask using a 0.1N KOH THF solution using a burette. KO at this time
Let the amount of H solution be S '(ml). At the same time, a blank test is performed, and the amount of the KOH solution at this time is defined as B ′ (ml). 6) Measure the total acid value according to the following equation.

[0143]

[Outside 8]

As the KOH THF solution, KOH6.
6 g was dissolved by adding 20 cc of ion-exchanged water.
720 cc, 100 cc of ion-exchanged water are added, and then methanol is added while stirring until the mixture becomes transparent.

Examples of the monomer for adjusting the acid value of the polymer component include acrylic acid such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid and the like.
Alternatively, there are β-alkyl derivatives, unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid and monoester derivatives thereof, and maleic anhydride. These monomers may be used alone or in combination with other monomers. By polymerizing, a desired polymer can be produced. Among them, it is particularly preferable to use a monoester derivative of an unsaturated dicarboxylic acid.

More specifically, for example, monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monoallyl maleate,
Monoesters of α, β-unsaturated dicarboxylic acids such as monophenyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monophenyl fumarate, etc .; monobutyl n-butenylsuccinate, monomethyl n-octenyl succinate, Monoesters of alkenyl dicarboxylic acids such as monoethyl n-butenylmalonate, monomethyl n-dodecenylglutarate, monobutyl n-butenyladipate, etc .; monomethyl phthalate, monoethyl phthalate, monobutyl phthalate, etc. And monoesters of aromatic dicarboxylic acids such as:

The carboxy group-containing monomer as described above may be added in an amount of 1 to 20% by weight, preferably 3 to 15% by weight, based on all monomers constituting the polymer side of the binder resin.

The reason that the monoester monomer of dicarboxylic acid is selected as described above is that it is not appropriate to use the acid monomer having high solubility in the aqueous suspension in the suspension polymerization. This is because it is preferable to use the compound in the form of an ester having low solubility.

In the present invention, the carboxylic acid groups and carboxylic acid ester sites in the copolymer obtained by the above method can be saponified by alkali treatment. That is, it is preferable that the carboxylic acid group or the carboxylic acid ester moiety is changed to a polar functional group by reacting with a cation component of an alkali. This is because, even if the polymer side component of the binder resin contains a carboxyl group that reacts with the metal-containing compound, if the carboxyl group is dehydrated, that is, the ring is closed, the efficiency of the cross-linking reaction decreases.

This alkali treatment may be carried out after the production of the binder resin, by introducing it as an aqueous solution into the solvent used during the polymerization and stirring. Examples of the alkali that can be used in the present invention include hydroxides of alkali metals and alkaline earth metals such as Na, K, Ca, Li, Mg, and Ba;
hydroxides of transition metals such as n, Ag, Pb, and Ni; hydroxides of quaternary ammonium salts such as ammonium salts, alkylammonium salts, and pyridium salts. Particularly preferred examples include NaOH and KOH. .

In the present invention, the saponification reaction does not need to be carried out over all of the carboxylic acid groups and carboxylic acid ester sites in the copolymer. I just need to change.

The amount of the alkali used in the saponification reaction is difficult to determine unconditionally depending on the type of the polar group in the binder resin, the dispersion method, the type of the constituent monomers, and the like. What is necessary is just 02-5 times equivalent. When the amount is less than 0.02 equivalent, the saponification reaction is not sufficient, and the number of polar functional groups generated by the reaction is reduced, and as a result, the subsequent crosslinking reaction becomes insufficient. On the other hand, when the amount exceeds 5 times equivalent, the functional group such as a carboxylic acid ester site is adversely affected by hydrolysis of the ester, generation of a salt by a saponification reaction, and the like.

When an alkali treatment of 0.02 to 5 times equivalent of the acid value is applied, the residual cation concentration after the treatment is 5 to 1 times.
It is contained between 000 ppm and can be preferably used to regulate the amount of alkali.

The vinyl resin according to the present invention has a glass transition temperature (Tg) of 50 to 70 ° C., preferably 55 to 65 ° C., from the viewpoint of storage stability. This may cause deterioration of the developer and offset at the time of fixing. On the other hand, when Tg exceeds 70 ° C., it adversely affects the entire fixing property.

The glass transition temperature (Tg _L ) of the vinyl low molecular weight polymer of the vinyl resin according to the present invention and the (Tg _H ) of the vinyl high molecular weight polymer have the following relationship: Tg _L ≧ Tg _H −5 (° C.) ) it is preferred to satisfy the, if Tg _L is less than Tg _H -5, there is a tendency that developing property is deteriorated. More preferably Tg
_L ≧ Tg _H is good.

As a method for producing a vinyl resin as a binder resin according to the present invention, a vinyl high molecular weight polymer and a vinyl low molecular weight polymer are separately synthesized by a solution polymerization method and then mixed in a solution state. Then, a solvent blending method in which the solvent is removed, a dry blending method in which the mixture is melt-kneaded by an extruder or the like, and a monomer constituting the vinyl-based high-molecular weight polymer obtained by the solution-based polymerization method and the like. , Suspension polymerization, washed with water and dried,
A two-stage polymerization method for obtaining a binder resin is exemplified. But,
The dry blending method has problems in terms of uniform dispersion and compatibility, and the two-stage polymerization method has many advantages in uniform dispersibility, but it is possible to increase a low molecular weight component to a high molecular weight component or more. In the presence of a low molecular weight component, not only is it very difficult to synthesize a desired high molecular weight component desired in the present invention, but also there are disadvantages such as unnecessary low molecular weight components being by-produced,
The solution blending method is most suitable for application to the present invention.

As a polymerization method which can be used in the present invention as a method for synthesizing the vinyl high molecular weight polymer according to the present invention, there are a solution polymerization method, an emulsion polymerization method and a suspension polymerization method.

Among them, the emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier, and polymerization is carried out using a water-soluble polymerization initiator. . In this method, the reaction heat can be easily adjusted, and the phase in which the polymerization is performed (oil phase composed of a polymer and a monomer)
And the aqueous phase are separate, so that the termination reaction rate is low, resulting in a high polymerization rate and a high degree of polymerization. Further, due to the relatively simple polymerization process and the fact that the polymerization product is fine particles, in the production of toner,
It is advantageous as a method for producing a binder resin for a toner, because it can be easily mixed with a colorant, a charge control agent and other additives.

However, the resulting polymer tends to be impure due to the added emulsifier, and it is necessary to perform an operation such as salting out to remove the polymer. To avoid this inconvenience, suspension polymerization is advantageous.

In the suspension polymerization, 100 parts by weight or less of the monomer (preferably 1 part by weight) is added to 100 parts by weight of the aqueous solvent.
(0 to 90 parts by weight). Examples of usable dispersants include polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, and the like. There is an appropriate amount in terms of the amount of a monomer relative to an aqueous solvent, and generally 0.05 to 1 based on 100 parts by weight of an aqueous solvent. Used in parts by weight. The polymerization temperature is suitably from 50 to 95 ° C, but should be appropriately selected depending on the initiator used and the intended polymer.

The vinyl high molecular weight polymer used in the present invention may be used alone or in combination with a monofunctional polymerization initiator as exemplified below in order to achieve the object of the present invention.

Specific examples of the polyfunctional polymerization initiator having a polyfunctional structure include 1,1-di-t-butylperoxy-
3,3,5-trimethylcyclohexane, 1,3-bis- (t-butylperoxyisopropyl) benzene,
2,5-dimethyl-2,5- (t-butylperoxy)
Hexane, 2,5-dimethyl-2,5-di- (t-butylperoxy) hexyne-3, tris- (t-butylperoxy) triazine, 1,1-di-t-butylperoxycyclohexane, , 2-Di-tert-butylperoxybutane, 4,4-di-tert-butylperoxyvaleric acid-n-butyl ester, di-tert-butylperoxyhexahydroterephthalate, di-tert-butylperoxy Azelate, di-t-butylperoxytrimethyl adipate, 2,2-bis- (4,4-di-t-
Butylperoxycyclohexyl) propane, 2,2-
a polyfunctional polymerization initiator having a functional group having a polymerization initiation function such as two or more peroxide groups in one molecule such as t-butylperoxyoctane and various polymer oxides, and diallyl peroxydicarbonate; In one molecule such as butylperoxymaleic acid, t-butylperoxyallyl carbonate and t-butylperoxyisopropyl fumarate, both a functional group having a polymerization initiation function such as a peroxide group and a polymerizable unsaturated group are contained. Selected from polyfunctional polymerization initiators having

Of these, preferred are 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-t-butylperoxycyclohexane, di-t-butyl Peroxyhexahydroterephthalate, di-t-butylperoxyazelate and 2,2-bis- (4,4-di-t-butylperoxycyclohexyl) propane, and t-butylperoxyallyl carbonate.

These polyfunctional polymerization initiators are preferably used in combination with a monofunctional polymerization initiator in order to satisfy various performances required as a binder for a toner.
Particularly, it is preferable to use the polyfunctional polymerization initiator together with a polymerization initiator having a decomposition temperature lower than the decomposition temperature for obtaining a half-life of 10 hours.

Specifically, benzoyl peroxide,
1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-di (t
-Butylperoxy) valerate, dicumyl peroxide, α, α'-bis (t-butylperoxydiisopropyl) benzene, t-butylperoxycumene, di-t
Organic peroxides such as -butyl peroxide and azo and diazo compounds such as azobisisobutyronitrile and diazoaminoazobenzene can be used.

These monofunctional polymerization initiators may be added to the monomer at the same time as the above-mentioned polyfunctional polymerization initiator. However, in order to maintain the initiator efficiency of the polyfunctional polymerization initiator properly, It is preferable to add the compound after the half-life of the polyfunctional polymerization initiator has elapsed under any polymerization conditions.

These initiators are used in 0.05 to 2 parts by weight per 100 parts by weight of the monomer.

The vinyl high molecular weight polymer used in the present invention contains a crosslinkable monomer as exemplified below in order to achieve the object of the present invention.

As the crosslinkable monomer, a monomer having two or more polymerizable double bonds is mainly used. Specific examples thereof include aromatic divinyl compounds, for example, divinylbenzene, divinylnaphthalene, etc .; Diacrylate compounds; for example, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate,
1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and acrylates of the above compounds replaced with methacrylates; diacrylate compounds linked by an alkyl chain containing an ether bond , Such as diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and acrylates of the above compounds instead of methacrylate Diacrylate compounds linked by a chain containing an aromatic group and an ether bond, for example, polyoxyethylene (2) -2,2-bis ( - hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,
2-bis (4-hydroxyphenyl) propane diacrylate and those obtained by replacing the acrylates of the above compounds with methacrylates; further, polyester-type diacrylate compounds, for example, trade name MANDA (Nippon Kayaku) . As multifunctional crosslinking agents, pentaerythritol acrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolpropane triacrylate, tetramethylolmethanetetraacrylate, oligoester acrylate, and acrylates of the above compounds to methacrylate Alternatives; triallyl cyanurate, triallyl trimellitate; and the like.

[0170] These cross-linking agents may be used in combination with other monomer components 10
1% by weight or less, preferably 0.00% with respect to 0% by weight
It is preferable to use it in the range of 1 to 0.05% by weight.

Of these crosslinkable monomers, those which are preferably used for the developer resin from the viewpoint of fixability and anti-offset properties include an aromatic divinyl compound (particularly divinylbenzene), an aromatic group and an ether bond. And diacrylate compounds linked by a chain containing the same.

The vinyl high molecular weight polymer according to the present invention is preliminarily mixed with a low molecular weight wax, so that phase separation in a micro region is alleviated, and the high molecular weight component is not re-aggregated.
A good dispersion state with the low molecular weight polymer is obtained.

Examples of the low molecular weight wax applicable to the present invention include polypropylene, polyethylene, microcrystalline wax, carnauba wax, sasol wax, paraffin wax, higher alcohol wax,
Examples include waxy substances such as ester waxes, and oxides and graft-modified products thereof.

The weight average molecular weight of these low molecular weight waxes is 30,000 or less, preferably 10,000 or less.
The addition amount is preferably about 1 to 20 parts by weight based on 100 parts by weight of the binder polymer component.

It is preferable that these low molecular weight waxes are added to and mixed with a vinyl resin in advance in producing a toner. In particular, a method in which the low-molecular-weight wax and the vinyl-based high-molecular-weight polymer are preliminarily dissolved in a solvent during the production of the vinyl-based resin, and then mixed with a vinyl-based low-molecular-weight polymer solution.

The solid concentration of such a polymer solution depends on the dispersion efficiency,
In consideration of prevention of deterioration of the resin at the time of stirring, operability, etc., 5 to 70
% Or less, and the preliminary solution of the vinyl polymer and the polyolefin polymer is 5 to 60% by weight.
Hereinafter, the content of the vinyl-based low-molecular polymer solution is preferably 5 to 70% by weight or less.

The method of dissolving or dispersing the vinyl polymer and the polyolefin polymer is carried out by stirring and mixing, and may be a batch system or a continuous system.

The method of mixing the low-molecular-weight polymer solution is to add 10 to 1000 polymerization parts of the low-molecular-weight polymer solution to the solid content of the preliminary solution and to carry out stirring and mixing. But it can be a continuous type.

Examples of the organic solvent used for mixing the solution for producing the vinyl resin according to the present invention include benzene, toluene, xylol, solvent naphtha No. 1,
Solvent Naphtha 2, Solvent Naphtha 3, cyclohexane, ethylbenzene, Solvesso 100, Solvesso 150, hydrocarbon solvents such as mineral spirits,
Alcohol solvents such as methanol, ethanol, iso-propyl alcohol, n-butyl alcohol, n-butyl alcohol, sec-butyl alcohol, iso-butyl alcohol, amyl alcohol, and cyclohexanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; Ester solvents such as ethyl acetate, n-butyl acetate, and cellosolve acetate; ether solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and methyl carbitol;
Among these, aromatic, ketone-based and ester-based solvents are preferred. They may be used in combination.

The method for removing the organic solvent is to heat the organic solvent solution of the polymer, remove 10 to 80% by weight of the organic solvent under normal pressure, and remove the remaining solvent under reduced pressure. At this time, the organic solvent solution has a boiling point of at least the boiling point of the used organic solvent,
It is necessary to keep the temperature below 0 ° C. Below the boiling point of the organic solvent, not only is the efficiency at the time of solvent distillation low, but also unnecessary shearing force is applied to the polymer in the organic solvent, and the redispersion of each constituent polymer is promoted, and in a micro state, Causes phase separation.
If the temperature exceeds 200 ° C., the depolymerization of the polymer proceeds, and not only oligomer formation due to molecular cleavage, but also incorporation of residual monomers into the product resin due to monomer generation, which is unsuitable as an electrophotographic toner binder Becomes

On the other hand, as a method for synthesizing the vinyl-based low molecular weight polymer according to the present invention, a known method can be used. However, in the bulk polymerization method, a polymer having a low molecular weight can be obtained by increasing the termination reaction rate by polymerizing at a high temperature, but there is a problem that the reaction is difficult to control.
In that regard, in the solution polymerization method, a low molecular weight polymer can be easily obtained under mild conditions by utilizing the difference in radical chain transfer depending on the solvent, and by adjusting the amount of the initiator and the reaction temperature, It is preferable to obtain a low molecular weight compound in the resin composition used in the present invention. In particular, minimize the amount of initiator used,
In order to minimize the influence of the initiator residue, a solution polymerization method under a pressurized condition is also effective.

Examples of the comonomer for obtaining a vinyl-based high molecular weight polymer and the monomer for obtaining a vinyl-based low molecular weight polymer used in the developing side of the present invention include the following.

For example, styrene, o-methylstyrene, m
-Methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene,
2,4-dimethylstyrene, pn-butylstyrene,
Styrene such as p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene and derivatives thereof; ethylene Ethylenically unsaturated monoolefins such as propylene, butylene and isobutylene; unsaturated polyenes such as butadiene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl acetate, vinyl propionate, Vinyl esters such as vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Stearyl, methacrylic Α-methylene aliphatic monocarboxylic esters such as phenyl, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, and n-acrylate Acrylates 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 Vinyl ketones such as methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyls such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone Vinyl compounds such as vinyl compounds, vinyl naphthalenes, and acrylic or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide;

Of these, a combination of monomers that results in a styrene-based copolymer and a styrene-acrylic copolymer is preferred.

It is preferable that both the vinyl-based low molecular weight polymer and the vinyl-based high molecular weight polymer contain at least 65 parts by weight of a styrene-based polymer component. By containing 65 parts by weight or more of each of the styrene components, the mixing property is improved.

The magnetic oxide particles used in the present invention preferably contain silicon. This improves the fluidity of the magnetic iron oxide particles and the fluidity of the magnetic toner.

The magnetic iron oxide particles of the present invention preferably have a silicon content of 0.1 to 0.2% by weight based on the iron element.

The magnetic iron oxide particles used in the present invention preferably have 0.01 to 1.00% by weight of silicon oxide in terms of SiO _{2 on the} surface.

Furthermore, the magnetic iron oxide particles used in the present invention may be treated with aluminum hydroxide.

The magnetic iron oxide particles used in the magnetic toner of the present invention are preferably used in an amount of 20 parts by weight to 200 parts by weight based on 100 parts by weight of the binder resin. It is more preferable to use 30 to 150 parts by weight.

In some cases, the magnetic iron oxide particles used in the magnetic toner of the present invention may be treated with a silane coupling agent, a titanium coupling agent, titanate, aminosilane, an organosilicon compound, or the like.

Examples of the silane coupling agent used for the surface treatment of the magnetic iron oxide particles used in the present invention include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane. Silane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-
Chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilane mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3
-Divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and the like.

Examples of the titanium coupling agent include isopropoxytitanium triisostearate, isopropoxytitanium dimethacrylate / isostearate,
Isopropoxy titanium tridodecyl benzene sulfonate, isopropoxy titanium tris dioctyl phosphate, isopropoxy titanium tri N-ethylaminoethyl aminato, titanium bis dioctyl pyrophosphate oxy acetate, bis dioctyl phosphate ethylene dioctyl phosphite, di-n-butoxy Bistriethanol aminato titanium and the like can be mentioned.

Examples of the organosilicon compound include silicone oil. Preferred silicone oils are those having a viscosity of about 30 to 1,000 centistokes at 25 ° C., such as dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil. Silicone oil and the like are preferred.

In the electrostatic image developing toner according to the present invention, conventionally known pigments or dyes such as carbon black and copper phthalocyanine can be used as coloring materials that can be added.

In the case of a negatively chargeable toner, the charge control agent of the toner for developing an electrostatic image used in the present invention may be a metal complex salt of a monoazo dye, a metal complex salt of salicylic acid, an alkyl salicylic acid, a dialkyl salicylic acid or a naphthoic acid. A negative charge control agent is preferably used.

For example, as the negative charge control agent,

[0198]

[Outside 9] The following three types are more effective as negative charge control agents combined with the magnetic iron oxide used in the present invention.

[0199]

[Outside 10] [Wherein X ₁ , X ₂ ; hydrogen atom, lower alkyl group, lower alkoxy group, nitro group, halogen atom m, m ′; 1-3 integers Y ₁ , Y ₃ ; hydrogen atom, C ₁ -C ₁₈ alkyl, alkenyl, sulfonamide, mesyl, sulfonic acid, carboxy ester, hydroxy, C ₁ -C ₁₈ alkoxy, acetylamino, benzoyl, amino group, a halogen atom n, n '; 1 to 3 integer Y _2, Y _4; Hydrogen atom, nitro group (X ₁ and X ₂ , m and m ′, Y ₁ and Y ₃ , n and n ′, and Y ₂ and Y ₄ may be the same or different)

[0200]

[Outside 11] Monoazo iron complex represented by

[0201]

[Outside 12]

Compound of aromatic hydroxycarboxylic acid, aromatic diol or aromatic dicarboxylic acid derivative having the above general formula and iron atom

[0203]

[Outside 13] [Wherein, Y ¹ , Y ² ; phenyl group, naphthyl group, anthryl group R ¹ , R ² ; halogen atom, nitro group, sulfonic acid group,
Carboxyl group, carboxylic ester group, cyano group, carbonyl group and alkyl group, alkoxy group, amino group R ³ , R ⁴ ; hydrogen atom, alkyl group, alkoxy group, phenyl group which may have a substituent, substituent An aralkyl group and an amino group R ⁵ , R ⁶ which may have: a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms k, j; an integer of 0 to 3 (not simultaneously 0), m, n; 1 or 2 (The above Y ¹ and Y ² , R ¹ and R ² , R ³ and R ⁴ , R ⁵ and R ⁶ , k and j, and m and n may be the same or different.)

NN'-bisarylurea derivative having the above general formula

[0205]

[Outside 14] Are preferred.

Although the details are not clear, the use of the above-mentioned negative charge control agent and the polymer component having an adjusted acid value used in the present invention tends to improve the image quality, particularly the fog. That has been confirmed.

Specific examples of the positive charge control agent include, for example,
Modified products such as nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and oniums such as phosphonium salts which are analogs thereof Salts and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (phosphorotungstic acid, phosphomolybdic acid, phosphomolybdic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferricyanide) Metal salts of higher fatty acids, acetylacetone metal complexes; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate;
And diorganotin borates such as dioctyltin borate and dicyclohexyl tin borate. These can be used alone or in combination of two or more.

The amount of the charge control agent to be used is 0.1 to 100 parts by weight of the binder resin in terms of the charge amount of the toner.
5.0 parts by weight are preferred.

The toner for developing an electrostatic image of the present invention is preferably mixed with an inorganic fine powder or a hydrophobic inorganic fine powder. For example, it is preferable to use silica fine powder or titanium oxide fine powder alone or in combination.

The fine silica powder used in the present invention includes both a so-called dry method produced by vapor phase oxidation of a silicon halide and a so-called fumed silica and a so-called wet silica produced from water glass. Although it can be used, fumed silica having few silanol groups on the surface and inside and having no production residue is preferable.

[0211] Further, the silica fine powder used in the present invention is preferably subjected to a hydrophobic treatment. To make it hydrophobic,
It is provided by chemically treating with an organic silicon compound or the like which reacts with or physically adsorbs silica fine powder. A preferred method is to treat the dry silica fine powder produced by the vapor phase oxidation of the silicon halide compound with a silane coupling agent or simultaneously with the silane coupling agent and an organic silicon compound such as silicone oil. Is mentioned.

Examples of the silane coupling agent used in the hydrophobic treatment include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, and allylphenyl. Dichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane,
Chloromethyldimethylchlorosilane, triorganosilane mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldi Siloxane and 1,3-diphenyltetramethyldisiloxane.

Examples of the organosilicon compound include silicone oil. Preferred silicone oils are those having a viscosity of about 30 to 1,000 centistokes at 25 ° C., such as dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil. Silicone oil and the like are preferred.

[0214] As a method of treating the silicone oil, for example, the silica fine powder treated with the silane coupling agent and the silicone oil may be directly mixed by using a mixer such as a Henschel mixer, or the silicone oil may be added to the base silica. May be injected. Alternatively, it may be prepared by dissolving or dispersing a silicone oil in an appropriate solvent, mixing with a base silica fine powder, and removing the solvent.

Further, a preferred system for hydrophobizing silica fine powder used in the present invention is a method of preparing by treating with dimethyldichlorosilane, then with hexamethyldisilazane, and then with silicone oil. No.

As described above, it is preferable to treat the silica fine powder with two or more silane coupling agents and then treat the oil with oil, since the degree of hydrophobicity can be effectively increased.

The silica fine powder subjected to the hydrophobic treatment and further to the oil treatment of the titanium oxide fine powder can be used in the present invention, and is preferably used in the same manner as the silica type.

If necessary, an external additive other than the silica fine powder may be added to the toner for developing an electrostatic image in the present invention.

For example, a charge auxiliary agent, a conductivity-imparting agent, a fluidity-imparting agent, an anti-caking agent, a release agent for hot roll fixing,
These are resin fine particles and inorganic fine particles that function as a lubricant, an abrasive and the like.

The fine resin particles have an average particle size of 0.1.
The polymerizable monomer constituting the resin is preferably styrene / o-methylstyrene / m-methylstyrene / p-methylstyrene / p-methoxystyrene / p-ethylstyrene. Styrene monomers, methacrylic acids such as acrylic acid and methacrylic acid,
Methyl acrylate / ethyl acrylate / acrylic acid n-
Butyl, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate
Acrylic esters such as 2-chloroethyl acrylate / phenyl acrylate, methyl methacrylate / ethyl methacrylate / n-propyl methacrylate / n-butyl methacrylate / isobutyl methacrylate / n-methacrylic acid
-Octyl / dodecyl methacrylate / methacrylic acid 2-
Methacrylates such as ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and other acrylonitrile, methacrylonitrile,
And monomers such as acrylamide.

The polymerization method includes suspension polymerization, emulsion polymerization,
Soap-free polymerization and the like can be used, but more preferably particles obtained by soap-free polymerization are preferred.

In particular, it has been confirmed that resin fine particles having the above-described characteristics have a great effect on drum fusion in a contact charging system such as a roller, brush or blade as a primary charging device.

As other fine particles, for example, a lubricant such as Teflon, zinc stearate, and polyvinylidene fluoride, among which polyvinylidene fluoride is preferable. Alternatively, abrasives such as cerium oxide, silicon carbide, and strontium titanate, among which strontium titanate is preferable. Alternatively, for example, a fluidity imparting agent such as titanium oxide and aluminum oxide, particularly a hydrophobic agent is preferable. A small amount of a caking preventing agent or a conductivity-imparting agent such as carbon black, zinc oxide, antimony oxide, and tin oxide, or white and black fine particles of opposite polarity can also be used as a developability improver.

The resin fine particles, inorganic fine powder, or hydrophobic inorganic fine powder mixed with the toner may be used as the magnetic toner 100.
0.1 to 5 parts by weight (preferably 0.1 to 5 parts by weight)
To 3 parts by weight).

To prepare an electrostatic image developing toner for developing an electrostatic image according to the present invention, the polymer component of the present invention and a pigment, dye or magnetic material as a colorant, a charge controlling agent, and the like. After thoroughly mixing the additives and the like with a mixer such as a ball mill, melting, kneading and kneading using a hot kneader such as a heating roll, kneader, extruder and the like, while the resins are mutually compatible. The toner for developing an electrostatic image according to the present invention can be obtained by dispersing or dissolving a pigment or dye, solidifying it by cooling, pulverizing and strictly classifying.

Further, as another method for obtaining the toner for developing an electrostatic image according to the present invention, the toner can be produced by a polymerization method. This suspension polymerization method toner is a polymerizable monomer and the charge control agent of the present invention, a pigment or a dye,
After uniformly dissolving or dispersing the magnetic iron oxide and the polymerization initiator (and, if necessary, a crosslinking agent and other additives) into a monomer composition, the monomer composition or the monomer A composition obtained by polymerizing the composition in advance is dispersed in a continuous phase (for example, water) containing a dispersion stabilizer using a suitable stirrer, and simultaneously subjected to a polymerization reaction to obtain toner particles having a desired particle size. is there. When the magnetic iron oxide used in the present invention is used in the polymerization method, it is preferable to perform a hydrophobic treatment in advance.

The magnetic iron oxide having a silicon element according to the present invention is produced, for example, by the following method.

Ferrous salt aqueous solution and Fe ²⁺ in the first aqueous solution
An oxygen-containing gas is passed through an aqueous ferrous salt reaction solution containing a ferrous hydroxide colloid obtained by reacting 0.90 to 0.99 equivalents of an aqueous alkali hydroxide solution with respect to In the formation, the water-soluble silicate is previously contained in either the aqueous alkali hydroxide solution or the ferrous salt containing the ferrous hydroxide colloid in terms of the silicon element with respect to the iron element, and the total content (0. 4 ~
2.0 to 100% by weight, and 85 to 100 ° C.
The magnetic iron oxide particles containing a silicon element are generated from the ferrous hydroxide colloid by passing an oxygen-containing gas and performing an oxidation reaction while heating in the temperature range described above.
Thereafter, 1.00 equivalent or more of an aqueous alkali hydroxide solution and the remaining water-soluble silicate relative to Fe ²⁺ remaining in the suspension after the oxidation reaction, that is, the total content (0.4 to
2.0% by weight) and then 85 to 85%
An oxidation reaction is performed while heating in a temperature range of 100 ° C. to generate magnetic iron oxide particles containing silicon element.

Next, in the case of treatment with an aluminum hydroxide, a water-soluble aluminum salt is added to the formed particles in an alkaline suspension in which the magnetic iron oxide particles containing the silicon element are formed in terms of aluminum element. After being added to be 0.01 to 2.0% by weight, the pH is adjusted to a range of 6 to 8, and aluminum hydroxide is precipitated on the surface of the magnetic iron oxide. Then, it is filtered, washed with water, dried and crushed to obtain the magnetic iron oxide of the present invention. Further, as a method of adjusting the smoothness and the specific surface area to the preferable ranges of the present invention, it is preferable to perform compression, shearing and spatula using a mix muller or a grinder.

Examples of the silicate compound to be added to the magnetic iron oxide used in the present invention include commercially available silicates such as sodium silicate and silicic acids such as sol silicic acid generated by hydrolysis or the like.

As the water-soluble aluminum salt to be added, aluminum sulfate and the like are exemplified.

As the ferrous salt, iron sulfate generally produced as a by-product in the production of titanium sulfate, iron sulfate produced as a by-product of cleaning the surface of a steel sheet, and iron chloride and the like can be used. .

An example of the image forming apparatus is schematically shown in FIG. 1, and an image forming method will be described based on the schematic.

Reference numeral 1 denotes a rotating drum-shaped electrostatic latent image carrier, around which a primary charging device 2, an exposure optical system 3, a developing device 4 having a toner carrier 5, a transfer device 9, and a cleaning device 11 are provided. Are located.

In this image forming apparatus, the surface of the electrostatic latent image carrier 1, which is a photosensitive member, is uniformly charged by the primary charging device 2, and the surface of the electrostatic latent image carrier is exposed by the exposure optical system 3. An electrostatic latent image is formed on the surface of the image forming apparatus 1.

Next, a toner coat layer is formed on the surface of the toner carrier 5 containing the magnet by the toner layer thickness regulating member 6 based on the constitution of the present invention, and the conductive portion of the electrostatic latent image carrier 1 is developed in the developing section. The electrostatic latent image formed on the electrostatic latent image carrier 1 is developed while applying an alternating bias, a pulse bias, and / or a DC bias by the bias applying means 8 between the conductive substrate and the toner carrier 5.

The developed toner image is conveyed to the transfer paper P, and is transferred to the transfer paper P electrostatically by applying a charge having a polarity opposite to that of the toner from the back surface of the transfer paper P by the transfer device 9 and the voltage applying means 10. .

The fixed image is obtained by passing the transfer paper P on which the toner has been transferred through the heating and pressurizing roller fixing device 12.

The magnetic toner remaining on the latent image carrier after the transfer step is removed by the cleaning device 11, and the steps following primary charging are repeated again.

[0240]

EXAMPLES The present invention will be described below with reference to specific examples, but the present invention is not limited to these examples.

(Production of resin composition ) Synthesis of low molecular weight polymer (L-1) 300 parts by weight of xylene was charged into a four-necked flask, and the inside of the vessel was sufficiently purged with nitrogen while stirring, and then the mixture was heated. Warm to reflux.

Under reflux, a mixture of 75 parts by weight of styrene, 18 parts by weight of n-butyl acrylate, 7 parts by weight of monobutyl maleate and 2 parts by weight of di-tert-butyl peroxide was added dropwise over 4 hours. Thereafter, the mixture was held for 2 hours to complete the polymerization, thereby obtaining a low molecular weight polymer (L-1) solution.

A portion of this polymer solution was sampled,
The polymer was dried under reduced pressure, and the obtained low molecular weight polymer (L-1) was obtained.
Was measured for GPC and glass transition point (Tg), as a result, weight average molecular weight (Mw) = 9,600, number average molecular weight (Mn) = 6,000, and peak molecular weight (PMw) =
8,500, Tg = 62 ° C., acid value (A ′ _VL ) = 25 mg
KOH / g.

The conversion of the polymer at this time was 97%.

Synthesis of High Molecular Weight Polymer (H-1) 180 parts by weight of degassed water and 20 parts by weight of a 2% by weight aqueous solution of polyvinyl alcohol were charged into a four-necked flask, and then 70 parts by weight of styrene and acrylic acid 25 parts by weight of n-butyl, 5 parts by weight of monobutyl maleate, 0.005 parts by weight of divinylbenzene, and 2,2-bis (4,4-di-t
A mixture of 0.1 parts by weight of tert-butylperoxycyclohexyl) propane (half-life 10 hours, temperature: 92 ° C.) was added, and stirred to form a suspension.

After sufficiently replacing the inside of the flask with nitrogen, 8
The temperature was raised to 5 ° C. to initiate polymerization. After maintaining at the same temperature for 24 hours, 0.1 part by weight of benzoyl peroxide (half-life of 10 hours; temperature of 72 ° C.) was additionally added. Furthermore,
The polymerization was completed by holding for 12 hours.

To the suspension after the completion of the reaction, an aqueous NaOH solution equivalent to six times the acid value (AV = 7.8) of the obtained high molecular weight polymer (H-1) was added, and the mixture was stirred for 2 hours. Was.

The high molecular weight polymer (H-1) was separated by filtration, washed with water, dried, and analyzed.
Mw = 1.2 million, Tg = 62 ° C., acid value (A ′ _VH ) = 6 m
gKOH / g.

Preparation of Binder In a four-necked flask, 100 parts by weight of xylene, 25 parts by weight of the high molecular weight polymer (H-1), and 4 parts by weight of polypropylene (Mw = 6,000) were charged, and the temperature was raised. Then, the mixture is stirred under reflux to perform preliminary dissolution. After maintaining in this state for 12 hours, a uniform pre-dissolved solution (Y-1) of the polymer (H-1) and the polypropylene was obtained.

A part of the pre-dissolved solution was sampled,
The solid was dried under reduced pressure and the glass transition point of the obtained solid was measured.

On the other hand, the low molecular weight polymer (L-
300 parts by weight of the homogeneous solution of 1) is introduced and refluxed.

After the above pre-dissolved solution (Y-1) and the low molecular weight polymer (L-1) solution were mixed under reflux, the organic solvent was distilled off, and the obtained resin was cooled, solidified and pulverized. Resin 1 for toner was obtained.

When the resin 1 was analyzed, PMw = 11
The area ratio in the molecular weight distribution of GPC of the resin composition having a molecular weight of 100,000 and 1,000,000 or more is 9.2%, Tg = 62.5 ° C.,
The THF insoluble content was 2.1% by weight.

Similarly, the amounts of monobutyl maleate, styrene, n-butyl acrylate and the amount of initiator were adjusted to obtain resins 2 to 8 and comparative resin 1 shown in Table 1.

[0255]

[Table 1]

(Production of Magnetic Iron Oxide Particles) An aqueous solution of ferrous sulfate was mixed with an aqueous solution of sodium hydroxide in an amount of 0.95 equivalent to Fe ²⁺ , and then mixed with an aqueous solution of ferrous iron containing Fe (OH) _2. An aqueous salt solution was produced.

Thereafter, sodium silicate was added so as to be 1.0% in terms of silicon element with respect to iron element. Next, air was passed through the aqueous ferrous salt solution containing Fe (OH) ₂ at a temperature of 90 ° C. to cause an oxidation reaction, thereby producing magnetic iron oxide particles containing a silicon element.

Further, 0.1% of sodium silicate was added to this suspension.
1.05 equivalents of an aqueous solution of sodium hydroxide in which (silicon element conversion with respect to iron element) is dissolved with respect to the remaining Fe ²⁺ , and while further heating at a temperature of 90 ° C., oxidize and contain silicon element Magnetic iron oxide particles were produced.

The produced magnetic iron oxide particles are washed, filtered, and dried by a conventional method, and then the aggregated magnetic iron oxide particles are subjected to crushing treatment (consolidation crushing treatment using a mix muller).
Magnetic iron oxide particles 1 were obtained. The particle size was 0.21 μm, the content of silicon element was 1.09%, and the amount of surface SiO _{2 was} 0.19%.
Met.

(Production of Toner) Resin 1 100 parts by weight Magnetic iron oxide 1 100 parts by weight Negative charge control agent (following formula) 2 parts by weight

[0261]

[Outside 15]

The above mixture was melt-kneaded with a biaxial extruder heated to 140 ° C., the cooled kneaded material was coarsely pulverized by a hammer mill, and the coarsely pulverized material was finely pulverized by a jet mill. Was classified with a fixed wall type air classifier to produce a classified powder. Furthermore, the ultrafine powder and coarse powder were simultaneously strictly classified and removed by a multi-segment classification device (Elbow Jet Classifier manufactured by Nippon Steel Mining Co., Ltd.) utilizing the Coanda effect to obtain a weight average particle size (D4) 6. 0.8 μm (particle size 12.7 μ
(m content of magnetic toner particles: 0.2%).

100 parts by weight of this magnetic toner, 1.2 parts by weight of hydrophobic silica fine powder (BET 300 m ² / g) treated with dimethyldichlorosilane, treated with hexamethyldisilazane, and then treated with dimethylsilicone oil. And styrene-acrylic fine particles (average particle diameter: 0.05 μm) obtained by soap-free polymerization were mixed with a Henschel mixer to prepare a magnetic developer (toner No. 1).

Toners 2 to 8 and Comparative Toner 1 were prepared in the same manner except that the kind of resin used was changed. Table 2 shows the correspondence between the toner and the resin used, and the physical properties of the resin components when the toner was formed. Table 3 shows the acid value of the toner.

[0265]

[Table 2]

[0266]

[Table 3] [Production of developing sleeve] Production example-A graphite (manufactured by Showa Denko KK, UFG-10, degree of graphitization 100%, major axis diameter 5μ, thickness 0.5μ or less) 100
Parts by weight resol type phenol resin 100 parts by weight PMMA resin particles (positive chargeability, average particle size 2μ) 4
Parts by weight

The above coating material was added to 76 parts of butyl alcohol, mixed, and then dispersed in a ball mill containing 200 μm diameter balls as media particles for 10 hours. Thereafter, the balls were separated using a 64 mesh screen to obtain a stock solution (solid content: 24 wt%). This stock solution is referred to as stock solution-A.

Production Example-B A stock solution (solid content: 24 wt%) was obtained in the same manner as in Production Example-A, except that among the materials in Production Example-A, graphite was changed to zinc stearate. This stock solution is referred to as stock solution-B.

Production Example-C graphite (manufactured by Showa Denko KK, UFG-10, major axis diameter 5)
μ) 100 parts by weight Epoxy resin 100 parts by weight Spherical alumina particles (positive chargeability, number average particle size 0.3
μ, sphericity 1.0) 5 parts by weight

The above material was replaced with normal propyl alcohol 7
After adding to 5 parts and mixing, the mixture was dispersed by a sand mill filled with steel balls having a diameter of 1 mm, and after the dispersion, the steel balls were removed to obtain a stock solution (solid content: 25 wt%). This stock solution is referred to as stock solution-C.

Preparation Example of Sleeve- Stock solution A-20 parts of butyl alcohol was added to A to prepare a coating solution (solid content 20 wt%). This coating solution was coated on an Al carrier substrate (aluminum cylinder) having a diameter of 20 mm by a dipping method to form a 10 μm film, and then heated and cured at 150 ° C. for 30 minutes in a hot air drying furnace to prepare a developing sleeve A.

The surface roughness (Ra) of the formed coating layer on the aluminum substrate was 2.5 μm.

[0273] except that the stock solution -A stock solution -B Production Example -B Preparation -A of the sleeve was adjusted developing sleeve B in the same manner as in Production Example -A.

Preparation Example of Sleeve-C A developing sleeve C was prepared in the same manner as in Preparation Example-A, except that the stock solution C was applied as it was by a spray method and cured by ultraviolet rays.

Comparative Production Example-a The surface was roughened by sandblasting on an aluminum carrier substrate having a diameter of 20 mm to provide the same surface roughness (Ra = 2.5 μ) as in Example-A.

Comparative Production Example-b A coating liquid was prepared in the same manner as in Production Example-A, except that the number average particle diameter of PMMA resin particles was changed to 40 μm among the materials in Production Example-A. The coating was performed according to -A to prepare a developing sleeve b.

Comparative Example Production-C A coating liquid was prepared in the same manner as in Production Example-C except that among the materials in Production Example-C, the particle size of the spherical alumina particles was changed to 0.02 μm. -C was applied to prepare a developing sleeve c.

Example 1 Using a toner 1 and a developing sleeve a, image evaluation was performed using a laser beam printer LBP-A309GII made by Canon under a high temperature and high humidity (35 ° C./90%) environment and a normal temperature and normal humidity environment. Was.

(1) Image density Ordinary copy paper (75 g / m ² ) in a high temperature and high humidity environment
5mm square solid black

[Outside]

Prints nine images (three rows and three rows) and a solid image over the entire surface, and uses a "Macbeth reflection densitometer" (manufactured by Macbeth) to determine the relative density of the white background portion of the printed image with a document density of 0.00. Was measured.

(2) Image Quality Roughness, fine line reproducibility, bitter dust, etc. were visually evaluated.

◎: Excellent ○: Good △: Practical possible ×: Practical impossible

(3) Fixability Under an ordinary temperature and normal humidity environment, 5
100 images of 9 mm square solid black (3 rows, 3 rows)
Using the printed sample, the fixed image was rubbed with a soft thin paper under a load of 50 g / cm ² , and the worst value of the decrease in image density before and after rubbing was evaluated as follows.

◎ (excellent): less than 5% ○ (good): 5% to less than 10% Δ (acceptable): 10% to less than 20% × (impossible): 20% or more

(4) Offset Resistance The offset resistance was evaluated by printing out a sample image having an image area ratio of about 5% and evaluating the degree of stain on the image.

◎ (excellent): not generated.） (Good): generated very slightly.

Δ (OK): Slightly occurs.

X (impossible): Stain on the image is remarkably generated.

On the other hand, after completion of the printout test, the state of fixation of the residual toner on the surface of the developing sleeve and the influence on the printout image were visually evaluated.

◎: Very good (not generated) ：: Good (almost no occurrence) △: Practical (there is sticking, but there is little influence on the image) △: Practical (there is sticking and image unevenness X: Not practical (many sticks and image unevenness)

Table 3 shows the above results.

Examples 2 to 10 Evaluations were made in the same manner as in Example 1 except that the toner carrier and the toner were changed as shown in Table 4.

Table 4 summarizes the results.

The results of Examples 1 to 10 were all excellent in fixing property, anti-offset sleeve stain, excellent image quality, and excellent in density durability in a high temperature and high humidity environment.

Comparative Examples 1-4 As shown in Table 4, the evaluation was performed in the same manner as in Example 1 except that the toner carrier and the toner were changed.

Table 4 summarizes the results.

The results of Comparative Examples 1 to 4 all show the fixing property,
At least one item of the offset resistance, sleeve contamination, density durability under high temperature and high humidity environment, and image quality were insufficient.

[0297]

[Table 4]

[0298]

As described above, according to the present invention, even in an environment in which the developer carrying member is contaminated and the charge amount of the toner is apt to decrease, the toner having an acid value is used to provide excellent fixability and anti-offset property. The effect of reducing the contamination of the developer carrying member and stabilizing the charging ability to the toner by using the developer carrying member is obtained, and a high-quality image excellent in long-term durability and environmental stability is obtained. It is possible to obtain.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an example of an image forming apparatus used in an image forming method of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 latent image carrier 2 primary charging device 3 exposure optical system 4 developing device 5 toner carrier 6 toner layer thickness regulating member 7 toner stirring means 8 developing bias power supply 9 transfer device 10 transfer current generator 11 cleaning means 12 fixing device 13 Magnetic toner

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI G03G 9/08 384 (72) Inventor Naohuni Kobori 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-7-13417 (JP, A) JP-A-3-200986 (JP, A) JP-A-6-202455 (JP, A) JP-A-4-181263 (JP, A) JP-A-60 -45261 (JP, A) JP-A-2-251862 (JP, A) JP-A-5-249735 (JP, A) JP-A-5-333595 (JP, A) (58) Fields investigated (Int. . ^7, DB name) G03G 13/08 - 13/095 G03G 15/08 - 15/095 G03G 9/08 - 9/097

Claims (24)

(57) [Claims] 1. A method for forming a layer of a magnetic toner on a developer carrier, which is arranged with a gap from an electrostatic latent image carrier, and applying an alternating current to the developer carrier, the image forming method having the step of developing the electrostatic latent image of the electrostatic latent image bearing member, said developer carrying member has at least a substrate and a coating layer, and said substrate surface is coated with the coating layer The coating layer
(I) a solid lubricant or a conductive agent, or a mixture of a solid lubricant and a conductive agent, and (ii) a number average particle size of 0.3.
The magnetic toner is formed of a composition containing at least a vinyl-based resin , a magnetic substance, and a charge controlling agent. The coating material contains spherical particles of about 30 μm and (iii) a binder resin. , the magnetic toner
Polymer component in over will have a 1 mgKOH / g or more acid number
And the polymer component in the magnetic toner, a) containing substantially no THF-insoluble matter, b) GPC chromatogram of the THF-soluble matter of the polymer component
In the region of molecular weight 3 × 10 ^{3 to} 3 × 10 ⁴
Has Npiku, and the molecular weight 1 × 10 ⁵ ~3 × 10 ⁶ of
Has a sub-peak or shoulder in the region, c) low molecular weight polymer component (GPC chromatogram smell
Value of the component having a molecular weight of less than 5 × 10 ⁴ )
(A _VL ) and high molecular weight polymer component (GPC chromatogram)
, The acid value of the component having a molecular weight of 5 × 10 ⁴ or more)
(A _VH ) satisfying the following relationship: A _VL > A _VH . 2. A low molecular weight polymer component of acid value (A _VL) is 21~35mgKOH / g, and the high molecular weight polymer component of acid value (A _VH) is in 0.5~11mgKOH / g And the difference (A _VL −A _VH ) is 10 to 27 mgK
2. The image forming method according to claim 1 , wherein the ratio is OH / g . 3. The vinyl resin has a low molecular weight of vinyl.
And contain coalescence and vinyl high-molecular weight polymer, the bi
The vinyl- based resin has a glass transition point (Tg) of 50 to 70 ° C., and the vinyl-based low molecular weight polymer has a glass transition point ( Tg).
g _L) and 該Bi sulfonyl-based high-molecular weight polymer glass transition point (T
g _H) and the image forming method according to claim 1 or 2 satisfies the following relationship Tg _L ≧ Tg _H -5. 4. The vinyl resin has a low molecular weight of vinyl.
And contain coalescence and vinyl high-molecular weight polymer, the bi
The glass transition point of the sulfonyl resin (Tg) is the 55 to 65 ° C., and the glass transition point of the vinyl-based low molecular weight polymer (T
g _L ) and the glass transition point of the vinyl high molecular weight polymer ( T
g _H) and the image forming method according to claim 1 or 2 satisfies the following relationship Tg _L ≧ Tg _H. 5. A related polymer component in the magnetic toner of the following
The image forming method according to any one of claims 1 to 4 are satisfied therewith. [Outside 1] 6. The vinyl-based low molecular weight polymer and the vinyl
Both systems high molecular weight polymer is 3 to Claim contains at least a styrene monomer component unit 65 parts by weight or more
5. The image forming method according to any one of 5 . 7. A 2 through claim wherein the vinyl high-molecular weight polymer is a polymer produced using a polyfunctional polymerization initiator
7. The image forming method according to any one of 6 . 8. The vinyl-based high molecular weight polymer, according to any one of claims 2 to 6 is a polyfunctional polymerization initiator and a monofunctional polymerization initiator at least in combination with polymer produced Image forming method. 9. The chromatogram of GPC measured by the THF-soluble matter of the polymer component in the magnetic toner chromatography, 1 to claim polymer component showing a molecular weight of 1,000,000 or more is contained more than 3% 9. The image forming method according to any one of items 8 . 10. The image forming method according to any one of claims 1 to 9 solid lubricant is graphite. 11. The image forming method according to any one of claims 1 to 10 conductive agent is carbon black. 12. The image forming method according to any one of claims 1 to 11 wherein the spherical particles are methacrylate-based resin (PMMA). Claim 13 Arrange the gap with respect to the electrostatic latent image carrier.
Forming a layer of magnetic toner on the placed developer carrier,
While applying an alternating current to the developer carrier, the magnetic toner
Developing the electrostatic latent image on the electrostatic latent image carrier by
Image forming method, The developer carrier has at least a substrate and a coating layer,
A substrate surface is coated with the coating layer, and the coating layer comprises:
(I) Solid lubricant or conductive agent or solid lubrication
A mixture of a good and a conductive agent, and (ii) a number average particle size of 0.3.
球状 30 μm spherical particles and (iii) a binder resin
Magnets used in image forming methods formed with a coating agent
In the toner, The magnetic toner includes at least a vinyl resin, a magnetic material and a belt.
The magnetic toner formed of a composition containing an electric control agent;
-The polymer component in has an acid value of 1 mgKOH / g or more
And The polymer component in the magnetic toner, a) substantially free of THF insolubles; b) GPC chromatogram of THF-soluble component of polymer component
At a molecular weight of 3 × 10 ^Three  ~ 3 × 10 ^Four  May area
And a molecular weight of 1 × 10 ^Five  ~ 3 × 10 ⁶  of
Have sub-peaks or shoulders in the region, c) Low molecular weight polymer component (in GPC chromatogram
And a molecular weight of 5 × 10 ^Four Acid value of the component)
(A _VL ) And high molecular weight polymer component (GPC chromatogram)
At a molecular weight of 5 × 10 ^Four  Acid value of the above components)
(A _VH ) And the following relationship A _VL > A _VH A magnetic toner characterized by satisfying the following. 14. An acid value (A) of the low molecular weight polymer component. _VL )
Is 21 to 35 mgKOH / g, and the high molecular weight
Acid value (A _VH ) Is 0.5 to 11 mgKOH / g
And the difference (A _VL -A _VH ) Is 10 to 27 mg
14. The magnetic toner according to claim 13, which is KOH / g. 15. The vinyl resin has a vinyl low molecular weight.
Containing a polymer and a vinyl high molecular weight polymer,
When the glass transition point (Tg) of the vinyl resin is 50 to 70 ° C
And the glass transition point of the vinyl-based low molecular weight polymer
(Tg _L  ) And the glass transition point of the vinyl high molecular weight polymer
(Tg _H  ) And the following relationship Tg _L  ≧ Tg _H  -5 The magnetic toner according to claim 13 or 14, which satisfies the following.
- 16. The vinyl resin has a vinyl low molecular weight.
Containing a polymer and a vinyl high molecular weight polymer,
When the glass transition point (Tg) of the vinyl resin is 55 to 65 ° C.
And the glass transition point of the vinyl-based low molecular weight polymer
(Tg _L  ) And the glass transition point of the vinyl high molecular weight polymer
(Tg _H  ) And the following relationship Tg _L  ≧ Tg _H The magnetic toner according to claim 13 or 14, which satisfies the following.
- 17. The polymer component in the magnetic toner according to the following:
Claim 13 which satisfies the relationship.
On the magnetic toner. [Outside 2] 18. The vinyl-based low molecular weight polymer and the vinyl
High molecular weight polymer Are both styrene-based
16. A polymer composition containing at least 65 parts by weight of a monomer component unit.
18. The magnetic toner according to any one of the above items. 19. The vinyl high molecular weight polymer is polyfunctional.
15. A polymer obtained by polymerization using a polymerization initiator.
19. The magnetic toner according to any one of the above items. 20. The vinyl-based high molecular weight polymer is polyfunctional.
At least a combination of a functional polymerization initiator and a monofunctional polymerization initiator.
19. The polymer according to claim 14, which is a polymer obtained by polymerization.
A magnetic toner according to any one of the above. 21. THF of a polymer component in the magnetic toner
GPC chromatogram measured by solubles
Contains 3% or more of a polymer component having a molecular weight of 1,000,000 or more.
21. The magnet according to any one of claims 13 to 20, wherein
toner. 22. A method according to claim 1, wherein said solid lubricant is graphite.
22. The magnetic toner according to any one of claims 13 to 21. 23. A method according to claim 1, wherein the conductive agent is carbon black.
23. The magnetic toner according to any one of claims 13 to 22. 24. The method according to claim 1, wherein the spherical particles are of a methyl methacrylate type.
24. The resin according to claim 13, which is a resin (PMMA).
3. The magnetic toner according to item 1.