JPH08220805A - Magnetic toner - Google Patents

Abstract

PURPOSE: To provide a magnetic toner which is low in toner consumption, contributes to formation of sharp images, has improved low-temp. fixability and offset resistance, does not fog in long-term durability and has stable electrostatic charge performance. CONSTITUTION: This magnetic toner has magnetic toner particles contg. a polymer component, a magnetic material and charge control agent and inorg. fine powder. The magnetic toner has the grain size distribution satisfying the conditions -5X+35<=Y<=-25X+180 and 3.5<=X<=6.5 when the weight average diameter (D4 ) of the magnetic toner is defined as X (μm) and the ratio of the toner particles of a grain size <=3.17μm in the number distribution of the magnetic toner as Y (number %). The polymer component does not substantially contain a THF insoluble content. The polymer component has a main peak in a region of mol.wt. 3×10<3> to 3×10<4> and has a sub-peak or shoulder in a region of mol.wt. 1×10<5> to 3×10<6> . The acid value of the low-mol.wt. polymer is higher than the acid value of the high-mol.wt. polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic toner used in electrophotography, electrostatic printing, magnetic recording and the like.

[0002]

2. Description of the Related Art Conventionally, a number of electrophotographic methods are known, but generally, a photoconductive material is used to form an electric latent image on a photoconductor by various means, and then the electrophotographic image is formed. The latent image is developed with toner to make it a visible image. If necessary, the toner image is transferred to a transfer material such as paper, and then the toner image is fixed on the transfer material by heat or pressure to obtain a copy. It is a thing.

In recent years, in addition to conventional copying machines, a large number of devices using electrophotography have been used, such as printers and facsimiles. Particularly in printers and facsimiles, a developing device using one-component toner is often used because it is necessary to make the copying device small.

Unlike the two-component system, the one-component developing system does not require carrier particles such as glass beads and iron powder, so that the developing device itself can be made compact and lightweight. Further, since the two-component developing system needs to keep the toner concentration in the carrier constant, a device for detecting the toner concentration and supplying a required amount of toner is required. Therefore, also in this case, the developing device becomes large and heavy. Such a device is not necessary in the one-component developing system, and it is preferable because it can be made small and light.

Further, in copying machines, there is always a demand for higher speed and stabilization. Especially for medium speed machines and high speed machines, the two-component development method is the mainstream. This is because, with such a relatively large machine, the stability for long-term use at high speed becomes more important than the problem of the size and weight of the developing device. Generally, the toner of the two-component toner is colored with carbon black or the like, and the rest is composed of a polymer. For this reason, the toner particles are light and have no force other than electrostatic force to adhere to the carrier particles. Therefore, especially at high-speed development, the toner is scattered, and the lens, the original glass, the transport section, etc. are contaminated over a long period of time, which may cause image deterioration. May impair stability. Therefore, a two-component toner has been put into practical use in which a magnetic substance is contained in the toner to make the toner heavy, and at the same time, magnetic particles are attached to the magnetic carrier particles by magnetic force as well as electrostatic force to prevent scattering.

As described above, the toner containing the magnetic material is becoming more and more important.

In addition, LED and LBP printers have become the mainstream of the market in recent years as the printer device, and the direction of technology is higher resolution, that is, 400, 600, 800 or 1200d instead of 240, 300 dpi.
It has become pi. Therefore, the developing system is also required to have higher definition. Further, the copiers are also becoming more sophisticated, and as a result, they are moving toward digitalization. In this direction, the method of forming an electrostatic charge image by a laser is mainly used, and therefore, it is also advancing toward high resolution, and here also, as in the case of a printer, a high resolution / high definition developing method is required. . For this reason, the particle size of the toner is being reduced, and Japanese Patent Application Laid-Open No. 1-112253, Japanese Patent Application Laid-Open No. 1-191156, and Japanese Patent Application Laid-Open No. 2-214 have been developed.
No. 156, JP-A-2-284158, JP-A-3-181952, and JP-A-4-162048 propose toners having a specific particle size distribution and a small particle size.

Further, with the increasing awareness of resource saving, it is required to further reduce the toner consumption amount (the amount of toner used for forming one image),
The above-mentioned proposal regarding the fine particle size toner has not been sufficient.

By the way, in the one-component magnetic development system, since the toner is developed in a chain (generally called "brush") at the time of development, the resolution in the horizontal direction of the image is worse than that in the vertical direction. In addition, the toner tends to be overlaid on the line as compared with the solid black image, and the toner consumption amount is likely to increase. In the non-image area in the latter half of the developed image, the tailing phenomenon due to the protrusion of the ears is apt to occur, and a rough image tends to occur as compared with the two-component developing method. In addition, the amount of toner on the line having a width of about 400 μm may reach almost twice.

Therefore, as a method of further improving the image reproducibility, it is possible to make the ears of the magnetic toner shorter and denser. The relationship between the magnetic strength of the magnetic toner and the shape of the spikes is also qualitatively understood as follows. That is, when the magnetic toner has a large magnetization intensity, a strong attractive force along the magnetic field direction and a strong repulsive force in the direction perpendicular to the magnetic field are generated between the magnetic toner particles. Therefore, when the magnetization intensity is high, the ears formed by the magnetic toner are long, and the ears on the toner carrier have a low density, and the individual ears are thin. On the other hand, when the magnetic toner has a low magnetization strength, the ears are short and the ears on the toner carrier become dense, but the individual ears are thick because the binding between the magnetic toner particles is not broken. It becomes shorter and becomes aggregated. In this case, the magnetic toner particles existing inside the ears are less likely to come into contact with the surface of the toner carrier, resulting in poor charging. Such poorly charged magnetic toner particles cause fog on the image and deteriorate the image quality. That is, as the content of the magnetic material is the same, the finer the toner, the shorter and denser the ears. Furthermore, as the toner particle size becomes smaller, the amount of fine powder with a high charge amount increases, and it is expected that the latent image electric field can be easily filled with a small amount of toner. A large amount of toner tends to have an insufficient image density.

Further, when the toner is in the form of fine particles, there is a problem in that the fluidity is not so good, and charge-up occurs in the charging process, making charging unstable. Further, in the production process, over-pulverization is likely to occur in the pulverizing step, and it is difficult to obtain a desired particle size distribution. That is, the amount of fine powder smaller than the desired average particle size increases, which is not preferable in terms of production efficiency. Further, there is a problem in that the fog on the image is deteriorated due to the large amount of fine powder.

On the other hand, various methods and apparatuses have been developed for the process of fixing the toner image on a sheet such as paper.
The most popular method at present is the hot pressing method using a hot roller. The heat-pressing method using a heat roller is a method in which fixing is carried out by passing the toner image surface of a fixing target sheet under pressure while contacting the surface of a heat roller having a surface formed of a material having releasability for toner. . In this method, the surface of the heat roller and the toner image on the sheet to be fixed come into contact with each other under pressure, so that the thermal efficiency at the time of fixing the toner image on the sheet to be fixed is extremely good and quick fixing can be performed, It is very effective in high speed electrophotographic copying machines.

However, in the above-described heat roller fixing which has been frequently used, there is a so-called wait time (1) an image forming operation inhibition time until the heat roller reaches a predetermined temperature.

(2) The optimum temperature of the heating roller to prevent fixing failure and transfer of toner to the heating roller due to the temperature of the heating roller fluctuating due to passage of a recording material or other external factors. Therefore, it is necessary to increase the heat capacity of the heating roller or the heating body for this purpose, which requires a large amount of electric power and causes a temperature rise inside the image forming apparatus.

(3) Since the roller has a low temperature, when the recording material passes through the heating roller and is discharged, the recording material and the toner on the recording material are cooled slowly, so that the toner has a high adhesiveness. Therefore, offset or a paper jam due to the winding of the recording material may occur due to the curvature of the roller. Such problems have not been solved fundamentally.

However, in order to realize a fixing method that has a short wait time and low power consumption while achieving excellent fixability of a toner image on a recording material and prevention of offset, etc., the above-described fixing device is used. In addition to this, the characteristics of the toner are very important.

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 is sufficiently melted when heated to increase the releasability of the toner has been used. ,
While it is effective in preventing offset, it tends to cause deterioration in durability due to increased toner cohesiveness, unstable charging characteristics. Therefore, as other methods, various attempts have been made to improve the binder resin.

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 fixability becomes insufficient, and there arises a problem that the fixability at a low temperature required for high-speed development and energy saving, that is, the low-temperature fixability is deteriorated. .

Generally, in order to improve the low-temperature fixing property of the toner, it is necessary to reduce the viscosity of the toner at the time of melting to increase the adhesion area with the fixing substrate. For this reason, the Tg and the molecular weight of the binder resin used for this purpose are required. Is required to be low.

That is, since the low-temperature fixing property and the offset preventing property have opposite sides, it is very difficult to develop a toner satisfying these functions at the same time.

In order to solve this problem, for example, JP-B-51-23354 discloses a toner made of a vinyl polymer which is appropriately cross-linked by adding a cross-linking agent and a molecular weight modifier. 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 of an α, β unsaturated ethylenic monomer as a constituent unit is 3.5 to 4.0. Further, there have been proposed blend type toners in which Tg, molecular weight, gel content and the like are combined in a vinyl polymer.

Certainly, the toners proposed by these proposals have a lower fixing temperature (the lowest temperature at which fixing is possible) and an offset temperature (a temperature at which offset begins to occur), as compared with a toner made of a single resin having a narrow molecular weight distribution. However, if sufficient offset prevention performance is given, the fixing temperature cannot be lowered sufficiently, and if low temperature fixability is emphasized, the offset prevention performance will be insufficient. There was the problem of becoming.

Further, in place of these vinyl resins, a toner obtained by crosslinking a polyester resin which is essentially superior to vinyl resins in terms of low-temperature fixability and further adding an offset preventive agent is also special. Kaisho 57-20855
No. 9 publication. This product is excellent in both low-temperature fixing property and anti-offset property, but it has a problem in productivity as a toner (grindability).

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

Further, simply, two types of gel content different from the polyester resin (gelation degree of 80% or more and gelation degree of 1
A toner using a resin blended with a vinyl-based resin (less than 0%) is proposed in Japanese Examined Patent Publication No. 1-15063. Although this toner has good low-temperature fixability, it has offset resistance and pulverizability. Not enough yet. If the proportion of the vinyl resin having a gelation degree of 80% or more is increased for the purpose of improving the offset resistance, the offset prevention property is improved, but the low temperature fixing property is remarkably lowered. Also, gelation degree 1
Sufficient grindability cannot be satisfied only by containing less than 0% of vinyl resin.

On the other hand, with respect to 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 (JP-A-57-57). 178249, 57-17
No. 8250), or a binder containing a vinyl-based resin monomer and a more specific monoester compound as an essential constituent unit and a polyvalent metal compound, and crosslinks via a metal (Japanese Patent Laid-Open No. 61- 110155, 61-110
No. 156) is introduced. further,
JP-A-63-214760 and 63-217362.
No. 63-217363 and No. 63-217364, a carboxylic acid group and a polyvalent metal ion which have a molecular weight distribution divided into two groups, a low molecular weight and a high molecular weight, are contained on the low molecular weight side. It is disclosed that the reaction is carried out by allowing the binder and the metal compound to react with each other by adding a dispersion of the metal compound to a solution obtained by solution polymerization and heating to cause the reaction. The metal compound is not sufficiently dispersed therein, and the physical properties required for the toner, particularly the fixability and the offset resistance have not been satisfied. Moreover, since it is necessary to mix a large amount of the metal compound with the binder resin, the mixed metal compound exhibits a catalytic action on the binder resin depending on the conditions, and the binder resin easily gels. As a result, the metal compound is mixed. Therefore, it is difficult to determine the manufacturing conditions for obtaining the desired toner, and even if the manufacturing conditions can be determined, it is difficult to obtain reproducibility.

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

Further, JP-A-2-168264, JP-A-2-235069, JP-A-5-173363,
In JP-A-5-173366 and JP-A-5-241371, the molecular weights, mixing ratios, acid values and ratios of the low molecular weight component and the high molecular weight component in the binder resin are controlled to fix, fix, offset and image. Although a binder composition for a toner and a toner having improved properties, blocking resistance, charging rising property, and the like have been proposed, the degree of completion is still low.

Particularly, in the adjustment of the acid value described in the above-mentioned publication, the dispersibility of a coloring agent such as magnetic iron oxide, a charge control agent (charge control agent), and other additives is poor, and a carrier such as a carrier or a sleeve carries a developer. Image deterioration such as fogging and reduced density due to contamination on the body surface occurs.

Further, further low temperature fixing is insufficient.

Further, in Japanese Patent Laid-Open No. 62-9256,
It discloses a binder composition for toner in which two kinds of vinyl resins having different molecular weights and resin acid values are blended. However, when such a binder resin is used,
To improve the compatibility and dispersibility of the toner constituent components, the kneading conditions must be strengthened, and the resin of the binder is affected by the cleavage of molecules and exhibits desired performance such as offset resistance. Will be difficult to do. Also, if kneading is carried out to such an extent that molecular cutting does not occur, dispersion of other additives will immediately occur, promoting contamination of the carrier of the carrier such as carrier and sleeve to the surface of the developer carrier, and fogging and scattering of the developing property. Will 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.

By the way, Japanese Patent Laid-Open No. 3-72505 discloses a vinyl-based toner binder having a molecular weight of 300,000 or more using a polyfunctional initiator. When such a resin is used, the fixability is to some extent. Although satisfactory, in addition to the above-mentioned problems, the performance of the developer deteriorates when left at high temperature. The cause of this phenomenon is not clear, but in our study, only the molecular breakage of the binder resin was promoted during toner formation, so that the proportion of the resin component having a sufficient molecular weight in the toner composition was It is supposed to be low and weak against thermal shock.

Further, the various performances required for the toners mentioned above are often reciprocal with each other, and it has been increasingly desired in recent years to satisfy both of them with high performance. Research has been conducted on comprehensive responses that also include characteristics, but there is still insufficient research.

Further, in order to increase the speed of the apparatus which has been required in recent years, the toner is required to have the toughness of a toner having a further low temperature fixing property and capable of withstanding high-speed development, and the charging stability capable of withstanding long-term durability. There is.

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

On the other hand, US Pat. No. 3,909,258 proposes a developing method using an electrically conductive magnetic toner. In this method, a conductive magnetic toner is supported on a cylindrical conductive sleeve having magnetism inside, and the conductive magnetic toner is brought into contact with an electrostatic image for development. At this time, in the developing section, a conductive path is formed by the toner particles between the surface of the recording medium and the sleeve surface, and the electric charge is introduced from the sleeve to the toner particles through the conductive path, and the conductive path is formed between the image area of the electrostatic image. The toner particles adhere to the image area and are developed by the cloning force. The developing method using this conductive magnetic toner is an excellent method that avoids the problems associated with the conventional two-component developing method, but on the other hand, since the toner is conductive, the developed image can be transferred from a recording medium to plain paper or the like. There is a problem that it is difficult to electrostatically transfer to the final support member.

As a developing method using a high-resistance magnetic toner capable of electrostatically transferring, there is a developing method utilizing dielectric polarization of toner particles. However, such a method has problems that the developing speed is inherently slow and the density of the developed image is not sufficiently obtained, and is practically difficult.

As another developing method using a high resistance insulating magnetic toner, the toner particles are triboelectrically charged by friction between the toner particles, friction between the toner particles and the sleeve, etc., and this is used as an electrostatic image holding member. A method of contacting and developing is known. However, these methods have problems that the number of contact between the toner particles and the friction member is small and triboelectric charging is apt to be insufficient, and the cloned force between the charged toner particles and the sleeve is increased and the charged toner particles are easily aggregated on the sleeve. It had, and was practically difficult.

However, in JP-A-55-18656 and the like, a new jumping developing method has been proposed which eliminates the above-mentioned problems. This involves applying a very thin coat of magnetic toner on a sleeve, tribocharging it and then developing it in close proximity to the electrostatic image. This method increases the chances of contact between the sleeve and toner by applying a very thin coating of magnetic toner on the sleeve, and enables sufficient triboelectrification. It is possible to obtain an excellent image by eliminating the agglomeration of the toner particles with each other and sufficiently rubbing the sleeve.

However, in the developing method using the improved insulating toner, there is an unstable factor related to the insulating toner used. This is because the insulating toner contains a considerable amount of fine powdery magnetic material mixed and dispersed, and a part of the magnetic material is exposed on the surface of the toner particles. The fluidity and the triboelectricity are affected, and as a result, various characteristics such as developing characteristics and durability of the magnetic toner, which are required for the magnetic toner, are changed or deteriorated.

More specifically, in the conventional jumping development method using a magnetic toner containing a magnetic substance, if a repeated development process (for example, copying) is continued for a long period of time, the developer containing the magnetic toner will be Liquidity deteriorated,
Normal frictional electrification cannot be obtained, the electrification is likely to be non-uniform, fog development is likely to occur in a low temperature and low humidity environment, and a serious problem on a toner image is likely to occur. Also,
When the adhesiveness between the binder resin forming the magnetic toner particles and the magnetic material is weak, the magnetic material is removed from the surface of the magnetic toner by repeated development steps, and the toner image density is lowered. There is.

When the dispersion of the magnetic material in the magnetic toner particles is uneven, small magnetic toner particles containing a large amount of the magnetic material accumulate on the sleeve, resulting in image density reduction and sleeve ghost. Occurrence of so-called shading unevenness may be seen.

Conventionally, proposals have been made regarding magnetic iron oxide contained in magnetic toners, but there are still points to be improved.

For example, JP-A-62-279352 and JP-A-62-278131 propose magnetic toners containing magnetic iron oxide containing silicon element. Such magnetic iron oxide intentionally allows the silicon element to be present inside the magnetic iron oxide, but the fluidity of the magnetic toner containing the magnetic iron oxide still has a point to be improved.

Further, Japanese Patent Publication No. 3-9045 proposes to control the shape of magnetic iron oxide into a spherical shape by adding a silicate. Magnetic iron oxide obtained by this method, since a large amount of silicon element is distributed inside the magnetic iron oxide because a silicate is used for controlling the particle size, the amount of silicon element present on the magnetic iron oxide surface is small, The improvement of fluidity of the magnetic toner tends to be insufficient.

Further, JP-A-61-34070 proposes a method for producing ferrosoferric oxide by adding a hydroxosilicate solution during the oxidation reaction to ferrosoferric oxide. The iron tetroxide produced by this method has a Si element in the vicinity of the surface, but the Si element exists as a layer in the vicinity of the surface of the iron tetroxide, and the surface is vulnerable to mechanical impact such as friction. Have a point.

In order to solve the above problems, the inventors of the present invention disclosed in Japanese Patent Application Laid-Open No. 5-72801 that magnetic silicon oxide contains silicon element and that the magnetic material surface contains all silicon element. A magnetic toner containing magnetic iron oxide in which 44 to 84% of the ratio is present is proposed.

However, in the magnetic toner containing the magnetic iron oxide, the fluidity of the toner and the adhesiveness with the binder resin have been sufficiently improved, but due to the uneven distribution of silicon element on the surface of the magnetic iron oxide, There has been a problem that the environmental characteristics, in particular, the charging characteristics deteriorate when left for a long time in a high humidity environment.

Further, Japanese Patent Application Laid-Open No. 4-362954 discloses a magnetic iron oxide containing both silicon element and aluminum element, but it has a drawback that environmental characteristics are insufficient like the above-mentioned patents. There is.

Further, Japanese Patent Laid-Open No. 213620/1993 discloses a magnetic iron oxide containing a silicon component and having the silicon component exposed on the surface. It has the drawback of being inadequate.

Furthermore, the magnetic iron oxide containing the above-mentioned silicon element and existing in the vicinity of the surface of the magnetic substance in a large amount tends to have insufficient dispersibility in the toner binder resin, and is excellent in each of the toner constituent components. In order to take advantage of the above characteristics, it is required for toner design to select a material having good compatibility and physical mixing property of each component.

[0052]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic toner which solves the above problems of the prior art.

That is, an object of the present invention is to provide a magnetic toner which consumes less toner than the conventional one, has a high image density, and can obtain a sharp image even in a small spot latent image.

A further object of the present invention is to provide a magnetic toner having improved low-temperature fixability and anti-offset property, less fog even in long-term durability, and stable charging performance.

A further object of the present invention is to provide a magnetic toner having a sharp pulverized particle size and high production efficiency in manufacturing.

[0056]

The present invention relates to a magnetic toner having a magnetic toner particle containing at least a polymer component, a magnetic material and a charge control agent, and an inorganic fine powder, and the weight of the magnetic toner. When the average diameter (D ₄ ) is X (μm) and the ratio of toner particles having a particle size of 3.17 μm or less in the number distribution of magnetic toner is Y (number%), the following condition −5X + 35 ≦ Y ≦ −25X + 180 ( 1) 3.5 ≦ X ≦ 6.5 (2) The magnetic toner has a particle size distribution satisfying (2), the polymer component is a) substantially free of THF insoluble matter, and b) the polymer component THF. In the gel permeation chromatography (GPC) chromatogram of the soluble component, the main peak was in the region of molecular weight 3 × 10 ^{3 to} 3 × 10 ⁴ , and the sub-peak was in the region of molecular weight 1 × 10 ^{5 to} 3 × 10 ^6. Or Has Yoruda, c) the acid value of the low molecular weight polymer (a region of molecular weight less than 5 × 10 ⁴ in GPC chromatogram) (A _VL) is, high molecular weight polymers (molecular weight 5 × 1 in GPC chromatogram
The magnetic toner is characterized by having an acid value (A _VH ) of 0 ⁴ or more).

Further, in the present invention, the ratio Y / the ratio Y of particles of 3.17 μm or less in the number particle size distribution of the magnetic toner and the ratio Z of particles Z of 3.17 μm or less in the volume particle size distribution Y /
The present invention relates to a magnetic toner characterized in that Z is 2.0 to 8.0.

Further, the present invention relates to a magnetic toner characterized in that the volume ratio of particles of 8 μm or more in the volume particle size distribution of the magnetic toner is 10% by volume or less.

Further, in the present invention, a low molecular weight polymer (a region having a molecular weight of less than 5 × 10 ⁴ in a GPC chromatogram) as a polymer component of the magnetic toner has an acid value A _{VL of 10} to 35 mg.
KOH / g, which is the acid value A _{VH of} the high molecular weight polymer (molecular weight range of 5 × 10 ⁴ or more in GPC chromatogram)
Is 0.5 to 11 mgKOH / g.

Further, in the present invention, the Tg of the magnetic toner is 50.
It is to 70 ° C., and to a magnetic toner relationship Tg _H of Tg _L and a high molecular weight polymer having a low molecular weight polymer of the magnetic toner being in the range of Tg _L ≧ Tg _H -5.

Further, in the present invention, the T _{g of the} magnetic toner is 55.
The magnetic toner is characterized by having a temperature of ˜65 ° C. and a relationship between T _gL of the low molecular weight polymer and T _gH of the high molecular weight polymer of the magnetic toner is in the range of T _gL ≧ T _gH .

Further, in the present invention, in the polymer component of the magnetic toner, the low molecular weight polymer has an acid value A _VL of 21 to 35 mg.
KOH / g and high molecular weight polymer has an acid value A _VH of 0.5
The present invention relates to a magnetic toner having a content of ˜11 mgKOH / g.

Further, in the present invention, in the polymer component of the magnetic toner, the difference A _VL -A _VH between the low molecular weight polymer and the high molecular weight polymer in the acid value is 10 ≤ (A _VL -A _VH ) ≤ 27. The present invention relates to a magnetic toner.

Furthermore, the present invention relates to a magnetic toner characterized in that the polymer component of the magnetic toner satisfies the following formula.

[0065]

[Equation 2]

Further, the present invention relates to a magnetic toner characterized in that both the low molecular weight and high molecular weight polymer components of the magnetic toner contain at least 65 parts by weight of a styrene polymer component.

The present invention further relates to a magnetic toner characterized in that the high molecular weight polymer component of the magnetic toner is a polymer polymerized with a polyfunctional polymerization initiator.

Furthermore, the present invention is characterized in that the high molecular weight polymer component of the magnetic toner is a polymer obtained by polymerizing at least a polyfunctional polymerization initiator and a monofunctional polymerization initiator in combination. Regarding

The present invention further relates to a magnetic toner containing magnetic iron oxide particles as the magnetic material, and the magnetic iron oxide contains silicon element.

Further, the present invention relates to a magnetic toner characterized in that the magnetic iron oxide has a silicon element content of 0.1 to 2.0% by weight based on the iron element.

Furthermore, the present invention relates to a magnetic toner characterized in that the magnetic iron oxide particles have 0.01 to 1.00% by weight of silicon oxide in terms of SiO _{2 on the} surface thereof.

Furthermore, the present invention relates to a magnetic toner characterized in that the magnetic iron oxide particles have a smoothness of 0.3 to 0.8.

Furthermore, the present invention relates to a magnetic toner characterized in that the magnetic iron oxide particles have a bulk density of 0.8 g / cm ³ or more.

Further, the present invention relates to a magnetic toner characterized in that the magnetic iron oxide particles have a specific surface area of 15.0 m ² / g or less.

The present invention further relates to a magnetic toner characterized in that the magnetic iron oxide particles are treated with 0.01 to 2.0% by weight of aluminum hydroxide as an aluminum element.

Further, the present invention relates to a magnetic toner characterized in that the total pore volume of the magnetic iron oxide particles is 7.0 × 10 ^{−3 to} 15.0 × 10 ⁻³ ml / g.

Further, in the present invention, the negative charge control agent is represented by the following general formula:

[0078]

Embedded image The present invention relates to a magnetic toner characterized by

Further, in the present invention, the negative charge control agent has the following general formula:

[0080]

[Chemical 4] The present invention relates to a magnetic toner characterized by

The magnetic toner of the present invention is obtained by adding at least inorganic fine powder to magnetic toner particles, and in addition, organic fine powder, resin fine powder, etc. having an average particle size smaller than the average particle size of the toner particles are added. It also includes those that have been done.

Further, the magnetic toner particles used in the present invention preferably have the above-mentioned particle size distribution and the constitution of the polymer component. That is, the weight average diameter (D ₄ ) of the magnetic toner
Is X (μm), and the ratio of the magnetic toner particles having a particle size of 3.17 μm or less in the number distribution is Y (number%), Y
Is less than -5X + 35, the effect of reducing the consumption is not sufficient, and when Y is greater than -25X + 180 or X is more than 6.5 μm, the resolution of an isolated single dot of a small spot deteriorates. At this time, if it is attempted to forcibly modify the image under developing conditions or the like, line thickening and scattering are likely to occur. Further, by virtue of having the above particle size distribution and the constitution of the polymer component, high productivity can be maintained even in the case of a magnetic toner in the form of fine particles.

The magnetic toner of the present invention contains substantially no THF insoluble matter. Specifically, it is 5% by weight or less, preferably 3% by weight or less, based on the resin composition.

The THF-insoluble matter in the present invention means the weight ratio of the polymer component (substantially cross-linked polymer) which becomes insoluble in the THF solvent in the resin composition in the toner,
It can be used as a parameter indicating the degree of crosslinking of the resin composition containing the crosslinking component. The THF-insoluble matter is defined as a value measured as follows.

That is, 0.5 to 1.0 g of a toner sample is weighed (w ₁ g) and a cylindrical filter paper (for example, No.
86R), put on a Soxhlet extractor, and extracted with 100 to 200 ml of THF as a solvent for 6 hours. After evaporating the soluble component extracted by the solvent,
Vacuum-dry at 100 ° C. for several hours, and weigh the amount of the THF-soluble resin component (w ₂ g). The weight of the components other than the resin component such as the magnetic substance or pigment in the toner is (w ₃ g). T
The HF insoluble content is obtained from the following formula.

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

If the THF insoluble content 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 examples of the present invention.

TH of the polymer component in the magnetic toner of the present invention
The GPC chromatogram measured by the F-soluble component has a molecular weight of 3 × 10 ^{3 to} 3 × 10 ⁴ (more preferably 5 × 10 3
^{3 to} 2 × 10 ⁴ ) with a main peak and a molecular weight of 1 × 10 ^{5 to} 3 × 10 ⁶ (more preferably 5 × 10 5).
^It has a sub peak or a shoulder in the region of ⁵ to 1 × 10 ⁶ ).

In the present invention, the molecular weight distribution of the polymer component of the toner is measured by GPC under the following conditions.

<GPC Measurement Conditions for Toner and Resin> Apparatus: GPC-150C (manufactured by Waters) Column: KF801-7 (manufactured by Showdex) 7 consecutive temperatures: 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

Generally, when the toner is made into fine particles such that the weight average particle diameter D ₄ is 3.5 μm ≦ D ₄ ≦ 6.5 μm, the cohesiveness is increased, and charge-up occurs in the charging process to make the charging unstable. It becomes easy to become. Further, in manufacturing, it is easy to over-pulverize in the pulverizing step, and it is difficult to obtain a desired particle size distribution. In other words, since the amount of fine powder smaller than the desired average particle size increases, the fog on the image deteriorates. Also,
It is not preferable in terms of production efficiency.

However, in the polymer component of the magnetic toner, the acid value A _VL of the low molecular weight polymer (region of molecular weight less than 5 × 10 ⁴ in GPC chromatogram) and the high molecular weight polymer (molecular weight 5 × 10 ⁴ in GPC chromatogram). By setting the relationship of the acid value A _{VH in} the above range) to the range of A _VL > A _VH , the fluidity and charging stability of the toner are improved. Also, in the pulverizing step, the pulverizability is good and the pulverized particle size becomes sharp.

Further, the volume ratio of particles of 8 μm or more in the volume particle size distribution of the magnetic toner is preferably 10% by volume or less in order to reduce scattering.

The magnetic toner of the present invention achieves higher image quality by having a small particle size, and achieves a low consumption amount by increasing the amount of fine powder having a high charge amount per unit weight of 5 μm or less, and a particle size distribution. It is intended to prevent the concentration from lowering by making it broad.

The reason why a larger amount of toner is generally developed in the line image area than in the solid image area is considered as follows. In the electrostatic latent image of the line image portion on the photoconductor, unlike the solid image portion, the lines of electric force are closely wrapping around the line latent image from the outside of the line latent image. Since a large amount of toner is attracted to and pressed against the photoreceptor latent image surface, more toner is easily developed on the line latent image surface.

The reason why the toner of the present invention has a smaller amount of toner on the line image portion than the conventional toner and the toner consumption can be reduced is considered as follows.

In the one-component developing system using magnetic toner,
The toner is developed on the surface of the photoconductor in a state where the toner particles are aggregated to some extent. The toner of the present invention has a high charge amount of 5 μm.
Since the magnetic force per toner is small because it contains a large amount of the following particles, and because the latent image potential is easily filled, more than necessary toner particles once developed in the line image area on the photoconductor are Against the force due to the wraparound of the latent image electric force lines,
We believe that it is possible to return onto the sleeve, leaving only the proper amount of toner in the line image area. That is, particles having a particle size of 5 μm or less reach the latent image on the photoconductor faster than particles having a large particle size because the charge amount per unit weight is high, and the lines of electric force of the latent image wrap around to weaken the developing electric field. This is because other particles are less likely to be affected by. Further, even in a solid black image, it is possible to increase the image density with a smaller amount by reducing the particle size, and it is expected that the consumption amount will be reduced.

The polymer component according to the present invention has a low molecular weight polymer (area of less than 5 × 10 ^{4 in} GPC chromatogram) having an acid value (A _VL ) of 21 to 35 mgKOH / g.
And the acid value (A _VH ) of the high molecular weight polymer (region of molecular weight 5 × 10 ⁴ or more in GPC chromatogram) is 0.5.
It is characterized in that it is -11 mgKOH / g.

As a result of intensive studies, the present inventors have found that in a toner resin composition comprising a low molecular weight polymer and a high molecular weight polymer, it is necessary that each polymer component has the above-mentioned acid value at low temperature fixability, It has been found that it is most effective in anti-offset property, in addition, in the present invention, it reduces fog in the toner particle size and improves 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 predominant, but the acid component is contained in this component, and the acid value of the high molecular weight polymer is 10 m or more.
It has been found that by increasing gKOH / g or more, the viscosity can be made lower than that of the resin composition having the same Tg and the same molecular weight distribution outside the above range.

This is because by setting the acid value of the high molecular weight polymer component to be 10 mgKOH / g or more lower than the acid value of the low molecular weight polymer component (acid value 0.5 to 11 mgKOH / g), the low molecular weight polymer component It is considered that the entanglement of the molecular chains of the high-molecular weight polymer component is suppressed to some extent, and thus the viscosity is reduced on the low temperature side and the elasticity is maintained on the high temperature side. This also means low temperature fixing in high speed machines,
This leads to improvement of development characteristics.

On the other hand, when the difference in the acid value exceeds 27, a problem occurs in the mixing property of the low molecular weight polymer component and the high molecular weight polymer component, and the durability offset property and the developability are deteriorated.

Further, the acid value of the low molecular weight polymer component is 21.
When it is more than mgKOH / g, the rising property of charging becomes good.

On the other hand, the acid value of the low molecular weight polymer component is 35 m.
If it exceeds gKOH / g, environmental characteristics, particularly developability under high humidity, deteriorates.

The acid value of the high molecular weight polymer component is 0.5.
When the amount is less than mgKOH / g, the miscibility with the low molecular weight polymer component (acid value 21 to 35 mgKOH / g) becomes a problem, and the developability, especially the fog prevention property is deteriorated.

The polymer component has an acid value / total acid value ratio value of 0.7 or less (more preferably 0.4 to 0.6).
Is more preferable. The acid value / total acid value is 0.
When it exceeds 7, the balance of charging of the toner, that is, the balance of charging / discharging tends to be a charging tendency, and the toner charging stability tends to be lowered.

The polymer component is the polymer component THF.
The GPC chromatogram of the soluble matter had a molecular weight of 3 × 10
It is preferable to have a minimum value (Min) in a region of ⁴ or more and less than 1 × 10 ⁵ . In order to achieve both low temperature fixability and high temperature offset resistance, it is preferable that the low molecular weight polymer component and the high molecular weight polymer component each have an independent molecular weight distribution.

Further, the polymer component of the toner resin composition of the present invention is such that, in the relation between the low molecular weight polymer component and the high molecular weight polymer component, the mixing ratio thereof is W _L : W _H = 50: 50 to 90. It is necessary to satisfy the following condition. The reason is that if the ratio of the low molecular weight component to the high molecular weight component is out of this range, the fixability and the offset resistance will be impaired. That is, if the content of the low molecular weight component is less than 50% by weight, the fixability is deteriorated, whereas if the content of the high molecular weight component is less than 10% by weight, the high temperature offset resistance is deteriorated.

Further, regarding the relationship between the mixed amount of these and the acid value,

[0110]

(Equation 3)

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

<Preparation of each component> [Device configuration] LC-908 (manufactured by Nippon Analytical Industry Co., Ltd.) JRS-86 (the same company; repeat injector) JAR-2 (the same company; autosampler) FC-201 (Gilson Company; 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: RI

In the sample, additives other than the polymer component are separated in advance. As a preparative method, the elution time at which the molecular weight becomes 5 × 10 ⁴ is measured in advance, and before and after that, the low molecular weight polymer component and the high molecular weight polymer component are fractionated. The solvent is removed from the collected sample to obtain a sample for acid value measurement.

<Measurement of Acid Value (JIS Acid Value)> 1) Precisely weigh 0.1 to 0.2 g of a crushed product of a sample, and let its weight be W (g).

2) Put the sample in a 20 cc Erlenmeyer flask,
10 cc of a mixed solution of toluene / ethanol (2: 1) is added and dissolved.

3) Add a few drops of an alcohol solution of phenolphthalein as an indicator.

4) Titrate the solution in the flask with a burette using an alcohol solution of 0.1N KOH. The amount of the KOH solution at this time is S (ml). A blank test is performed at the same time, and the amount of KOH solution at this time is
(Ml).

5) Calculate the acid value by the following formula.

[0121]

[Equation 4]

The total acid value in the present invention is measured as follows.

<Measurement of Total Acid Value> 1) The sample is used after removing additives other than the polymer components in advance. About 2g of crushed sample is precisely weighed and its weight is w '
(G).

2) A sample was placed in a 200 cc Erlenmeyer flask, 30 cc of 1,4-dioxane, 10 cc of pyridine,
Add 20 mg of 4-dimethylaminopyridine and dissolve 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 an alcohol solution of phenolphthalein as an indicator.

5) Titrate the solution in the flask with a burette using 0.1N THF solution of KOH.
The amount of the KOH solution at this time is S '(ml). At the same time, a blank test was performed and the amount of KOH solution at this time was changed to B '(m
l).

6) The total acid value is measured by the following formula.

[0129]

(Equation 5)

As a THF solution of KOH, KOH6.
6 g was added to 20 cc of deionized water to dissolve it, and then THF was added.
720 cc and 100 cc of ion-exchanged water are added, and then methanol is added with stirring until it becomes transparent.

Examples of the monomer for adjusting the acid value of the polymer component of the present invention include acrylic acid, methacrylic acid, α
-Acrylic acid such as ethylacrylic acid and crotonic acid and its α- or β-alkyl derivatives, unsaturated dicarboxylic acids such as fumaric acid, maleic acid and citraconic acid, and their monoester derivatives or maleic anhydride, etc. A desired polymer can be produced by copolymerizing these monomers alone or in combination with each other and copolymerizing them. Among these, it is particularly preferable to use a monoester derivative of 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-butenyl succinate, monomethyl n-octenyl succinate, Monoesters of alkenyl dicarboxylic acids such as monoethyl n-butenylmalonate, monomethyl n-dodecenyl glutarate, monobutyl n-butenyl adipate; phthalic acid monomethyl ester, phthalic acid monoethyl ester, phthalic acid monobutyl ester, etc. Aromatic dicarboxylic acid monoesters;

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

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

In the present invention, the carboxylic acid group and the carboxylic acid ester moiety in the copolymer obtained by the above method can be saponified by alkali treatment. That is, it is preferable to react with an alkali cation component to change the carboxylic acid group or the carboxylic acid ester moiety into a polar functional group. 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 in an anhydrous state, that is, in a closed ring state, the efficiency of the crosslinking reaction decreases.

This alkali treatment may be carried out after the binder resin has been produced, by adding it as an aqueous solution into the solvent used during the polymerization and stirring it. Examples of alkalis that can be used in the present invention include Na, K, Ca, Li, Mg and Ba.
Hydroxides of alkali metals and alkaline earth metals such as;
There are hydroxides of transition metals such as Zn, Ag, Pb, and Ni; hydroxides of quaternary ammonium salts such as ammonium salts, alkylammonium salts, and pyridinium salts, and particularly preferable 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 moieties in the copolymer, and the saponification reaction partially progresses to give polar functional groups. It should be different.

The amount of alkali used in the saponification reaction is difficult to determine depending on the type of polar group in the binder resin, the dispersion method, the type of constituent monomers, etc. It may be from 02 to 5 times equivalent. When the amount is less than 0.02 times the equivalent, the saponification reaction is not sufficient and the number of polar functional groups generated by the reaction is small, resulting in insufficient post-crosslinking reaction. On the other hand, when the amount exceeds 5 times the equivalent, the functional group such as the carboxylic acid ester moiety is adversely affected by hydrolysis of the ester, formation of a salt by saponification reaction, and the like.

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

The magnetic toner 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 storability, and when Tg is lower than 50 ° C., it is in a high temperature atmosphere. This causes deterioration of the developer and offset during fixing. Further, when Tg exceeds 70 ° C., the fixability is adversely affected.

The relationship between Tg _L of the low molecular weight polymer and Tg _H of the high molecular weight polymer of the resin composition according to the present invention is preferably in the range of Tg _L ≧ Tg _H −5 (° C.), and Tg _L Is less than Tg _H −5, the developability tends to be poor. More preferably T
g _L ≧ Tg _H is preferable.

As a method for producing the binder resin according to the present invention, a solution blending method in which a high molecular weight polymer and a low molecular weight polymer are separately synthesized by a solution polymerization method, these are mixed in a solution state, and then the solvent is removed. Also, a dry blending method of melt-kneading with an extruder or the like, and a low molecular weight polymer obtained by a solution polymerization method or the like are dissolved in a monomer constituting a high molecular weight polymer, suspension polymerization is performed, and washing with water is performed. Examples thereof include a two-step polymerization method of obtaining a binder resin by drying. However, the dry blending method has problems in uniform dispersion and compatibility, and the two-step polymerization method has many advantages such as uniform dispersibility, but the low molecular weight component is increased to the high molecular weight component or more. In the presence of a low molecular weight component, which is not possible, it is very difficult to synthesize a sufficient high molecular weight component desired in the present invention, and there is a drawback that unnecessary low molecular weight component is by-produced. The solution blending method is most suitable for application to the present invention.

As the polymerization method which can be used in the present invention as a method for synthesizing the high molecular weight component of the resin composition 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 with an emulsifier in the aqueous phase and polymerization is carried out using a water-soluble polymerization initiator. . In this method, it is easy to control the heat of reaction, and the phase in which the polymerization takes place (oil phase consisting of polymer and monomer)
And the aqueous phase are different, the termination reaction rate is low, and as a result, the polymerization rate is high and the polymerization degree is high. Further, in the production of toner, due to the relatively simple polymerization process and the fine particles of the polymerization product,
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 is apt to become impure due to the added emulsifier, and an operation such as salting out is required to take out the polymer, and suspension polymerization is convenient for avoiding this inconvenience.

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) is preferable. As the dispersant that can be used, polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, etc. are used, and there is an appropriate amount such as the amount of monomers in the aqueous solvent, but generally 0.05 to 1 per 100 parts by weight of the aqueous solvent. Used in parts by weight. The polymerization temperature is suitably 50 to 95 ° C., but it should be appropriately selected depending on the initiator used and the target polymer.

As the high molecular weight component of the resin composition used in the present invention, in order to achieve the object of the present invention, a polyfunctional polymerization initiator as exemplified below or a monofunctional polymerization initiator is used in combination.

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 , 2-di-t-butylperoxybutane, 4,4-di-t-butylperoxyvaleric acid-n-butyl ester, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxy Azelate, di-t-butylperoxytrimethyl adipate, 2,2-bis- (4,4-di-t-
Butyl peroxycyclohexyl) 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, t- Both a functional group having a polymerization initiation function such as a peroxide group and a polymerizable unsaturated group are contained in one molecule such as butyl peroxy maleic acid, t-butyl peroxy allyl carbonate and t-butyl peroxy isopropyl fumarate. Selected from polyfunctional polymerization initiators having.

Of these, preferred are 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-t-butylperoxycyclohexane and 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 toner.
In particular, it is preferable to use together with a polymerization initiator having a decomposition temperature lower than the decomposition temperature for obtaining the half-life of 10 hours of the polyfunctional polymerization initiator.

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, 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 polyfunctional polymerization initiator, but in order to keep the initiator efficiency of the polyfunctional polymerization initiator appropriate. It is preferably added after the polymerization time has passed the half-life indicated by the polyfunctional polymerization initiator under arbitrary polymerization conditions.

These initiators are used in an amount of 0.05 to 2 parts by weight based on 100 parts by weight of the monomer.

The high molecular weight component of the resin composition 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, and specific examples thereof include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and the like; 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 compounds obtained by replacing the acrylates of the above compounds 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 the acrylates of the above compounds replaced with 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 acrylate of the above compounds with methacrylates; further, polyester type diacrylate compounds, for example, trade name MANDA (Nippon Kayaku). . As the polyfunctional crosslinking agent, pentaerythritol acrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate, and acrylates of the above compounds into methacrylate. And the like; triallyl cyanurate, triallyl trimellitate; and the like.

These cross-linking agents are used as the other monomer component 10
1% by weight or less with respect to 0% by weight, preferably 0.00
It is preferably used in the range of 1 to 0.05% by weight.

Among these crosslinkable monomers, aromatic divinyl compounds (particularly divinylbenzene), aromatic groups and ether bonds are preferably used for the resin for developers from the viewpoints of fixing property and anti-offset property. Examples include chain-containing diacrylate compounds.

By mixing the polymer-side polymer constituting the resin composition according to the present invention with a low-molecular weight wax in advance, phase separation in the micro range is alleviated, the polymer component is not re-aggregated, A good dispersion state with the molecular polymer can be obtained.

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

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

These low molecular weight waxes are preferably added and mixed in the binder resin in advance during toner production. Particularly preferred is a method in which the low-molecular weight wax and the high-molecular weight polymer are pre-dissolved in a solvent during the production of the binder and then mixed with the low-molecular weight polymer solution.

The solid concentration of the polymer solution depends on the dispersion efficiency,
5 to 70 in consideration of deterioration of resin at the time of stirring and operability.
It is preferably not more than 5% by weight, preferably 5 to 60% by weight or less in the preliminary solution of the high molecular weight polymer component and the polyolefin polymer, and 5 to 70% by weight or less in the low molecular weight polymer solution.

The method of dissolving or dispersing the high molecular weight polymer component and the polyolefin polymer is carried out by stirring and mixing,
Batch type or continuous type can be used.

Then, the method of mixing the low molecular weight polymer solution is to add 10 to 1000 parts by weight of the low molecular weight polymer solution to the solid content of the preliminary solution and perform stirring and mixing. But it doesn't matter if it is a continuous type.

Examples of the organic solvent used for mixing the solution of the resin composition according to the present invention include benzene, toluene,
Hydroxyl solvents such as xylol, solvent naphtha 1, solvent naphtha 2, solvent naphtha 3, cyclohexane, ethylbenzene, solvesso 100, solvesso 150, mineral spirits, methanol, ethanol, iso-propyl alcohol, n-butyl alcohol, Alcoholic solvents such as sec-butyl alcohol, iso-butyl alcohol, amyl alcohol, cyclohexanol, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ester solvents such as ethyl acetate, n-butyl acetate, cellosolve acetate. Examples of the solvent include ether solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and methyl carbitol. Among these aromatic,
Ketone-based and ester-based solvents are preferred. Moreover, these may be mixed and used.

As a method of removing the organic solvent, after heating the organic solvent solution of the polymer, 10 to 80% by weight of the organic solvent is removed under normal pressure, and then the residual solvent is removed under reduced pressure. At this time, the organic solvent solution has a boiling point of 20% or more of the organic solvent used.
It is necessary to keep the temperature below 0 ° C. If the boiling point of the organic solvent is below the range, not only the efficiency during solvent evaporation is poor, but also unnecessary shearing force is applied to the polymer in the organic solvent, redispersion of each constituent polymer is promoted, and in a micro state. Cause phase separation.
Further, when the temperature exceeds 200 ° C., depolymerization of the polymer proceeds, and not only oligomer formation by molecular cleavage but mixing of residual monomer into the product resin due to monomer formation leads to unsuitable toner binder for electrophotography. Becomes

On the other hand, as a method for synthesizing the low molecular weight component of the binder resin according to the present invention, a known method can be used. However, in the bulk polymerization method, a low molecular weight polymer can be obtained by polymerizing at a high temperature to accelerate the termination reaction rate, but there is a problem that the reaction is difficult to control.
In that respect, in the solution polymerization method, a low molecular weight polymer can be easily obtained under mild conditions by utilizing the difference in chain transfer of radicals 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 product in the resin composition used in the present invention. In particular, minimize the amount of initiator used,
A solution polymerization method under pressure is also effective in that the influence of the residue of the initiator is suppressed as much as possible.

Examples of the comonomer for obtaining the polymer side component of the binder resin used for the developing side and the monomer for obtaining the low molecular weight side component 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 and its derivatives such as p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene and the like; ethylene. Ethylenically unsaturated monoolefins such as propylene, butylene, 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, meta Phenyl acrylic acid, dimethylaminoethyl methacrylate, alpha-methylene aliphatic monocarboxylic acid esters such as diethylaminoethyl methacrylate;
Methyl acrylate, ethyl acrylate, acrylic acid n-
Butyl, isobutyl acrylate, propyl acrylate,
Acrylic esters such as n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N
-N- such as vinylindole and N-vinylpyrrolidone
Vinyl compounds; vinyl naphthalene compounds; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide; and vinyl monomers used alone or in combination of two or more.

Of these, a combination of monomers that forms a styrene copolymer or a styrene acrylic copolymer is preferable.

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

The inventors of the present invention have disclosed in Japanese Unexamined Patent Publication (Kokai) No. 5-72801 that magnetic iron oxide contains silicon element, and the magnetic oxidation is such that 44 to 84% of the total silicon content is present near the surface of the magnetic material. A magnetic toner containing iron was proposed.

However, as described above, in this system, there is a problem in that the environmental characteristics, especially the charging characteristics deteriorate when left for a long time under high humidity.

Further, as the speed of image forming apparatuses such as printers increases and the number of durable sheets increases, there is a demand for toners having durability and extremely high material dispersibility.

By controlling the outermost surface, composition and structure of the magnetic iron oxide, the present inventors have found that the magnetic toner containing the magnetic iron oxide has excellent fluidity, long-term storage stability, durability and toner. It has been found that the magnetic substance dispersibility in the inside can obtain extremely excellent physical properties.

That is, in the present invention, the content of silicon element in the magnetic iron oxide used in the magnetic toner is 0.1 to 5.0% by weight, preferably 0.4 to 2.0, based on the iron element.
It is preferable that the content is wt% (more preferably 0.5 to 0.9 wt%).

When the content of elemental silicon is less than 0.4% by weight or the Fe / Si atomic ratio exceeds 4.0,
The improvement effect on the magnetic toner, especially the improvement of the fluidity of the magnetic toner is weak. When the content of the silicon element is more than 2.0% by weight or the Fe / Si atomic ratio is less than 1.2, environmental characteristics, in particular, the charging property deteriorates when left for a long period of time under high humidity. Further, the durability of the toner and the dispersibility of the magnetic iron oxide in the toner binder resin are deteriorated.

The preferred system of the magnetic iron oxide particles of the present invention is 0.01 on the surface of the magnetic iron oxide particles in terms of SiO _2.
~ 1.00 wt% (more preferably 0.05-0.3
(Wt%) silicon oxide is present. When the silicon oxide on the surface of the magnetic iron oxide particles is less than 0.01% by weight in terms of SiO ₂ , further improvement in fluidity of the magnetic toner cannot be expected. On the other hand, when the content exceeds 1.00% by weight, environmental characteristics, in particular, a decrease in the charge amount is caused in long-term storage under high humidity and long-term durability.

Further, as a preferable system of magnetic iron oxide particles, the smoothness thereof is 0.3 to 0.8, preferably 0.45.
To 0.7, and more preferably 0.5 to 0.7. The smoothness in the present invention is related to the amount of pores on the surface of the magnetic iron oxide, and when the smoothness is less than 0.3, there are many pores on the surface of the magnetic iron oxide, and water adsorption is promoted. To be done.

Furthermore, one of the more preferable systems of magnetic iron oxide particles is that the bulk density thereof is 0.8 g / cm ³ or more, preferably 1.0 g / cm ³ or more.
If the bulk density is less than 0.8 g / cm ³ , the physical mixability with other toner materials during toner production is adversely affected, and the dispersibility of the magnetic material in the toner deteriorates.

Furthermore, as one of the more preferable systems of magnetic iron oxide particles, the specific surface area thereof is 15.0 m ² / g or less,
It is preferable to satisfy 12.0 m ² / g or less. When the specific surface area exceeds 15.0 m ² / g, the water adsorption of the magnetic iron oxide particles increases, which adversely affects the hygroscopicity and the charging property of the toner containing the magnetic iron oxide particles.

As a result of diligent studies, the present inventors have found that the water adsorption properties of magnetic iron oxide are greatly related to the pores on the surface thereof, and it is most important to control the pore distribution. It was In terms of pore distribution, the total pore volume of the magnetic iron oxide particles is 7.0 × 10 ^{−3 to} 15.0 × 10.
^-3 ml / g, more preferably 8.0 x 10 ^{-3 to} 12.
It is preferably 0 × 10 ⁻³ ml / g.

When the total pore volume is less than 7.0 × 10 ^-3 ml / g, the adhesion with the toner binder resin is weak, and the magnetic iron oxide particles are detached from the toner, resulting in the image density. It is likely to cause adverse effects such as deterioration. Furthermore, the surface pores of the magnetic iron oxide particles are greatly involved in the adsorption of water, and greatly affect the water adsorption property of the toner containing the magnetic iron oxide particles. Further, the surface water content of the toner has a great influence on the charging characteristics of the toner.

The total surface pore volume of the magnetic iron oxide particles is 7.0.
When it is less than 10 ⁻³ ml / g, the water retaining ability of the magnetic iron oxide particles is remarkably reduced, and especially in an environment of low humidity, the toner containing the magnetic iron oxide particles is liable to be charged up and the image density is lowered. Prone to

When the total pore volume exceeds 15.0 × 10 ^-3 ml / g, the water adsorption property of the magnetic iron oxide particles increases, and the magnetic iron oxide particles are contained especially in an environment of high humidity. The toner is liable to absorb moisture when left standing, resulting in a decrease in charge amount, and as a result, a decrease in image density.

Further, the magnetic iron oxide particles used in the present invention are treated with 0.01 to 2.0% by weight (more preferably 0.05 to 1.0% by weight) of aluminum hydroxide as an aluminum element. Preferably.

Although the reason is not clear, it was confirmed that it is possible to further stabilize the charge of the toner by treating the surface of the magnetic iron oxide particles with aluminum hydroxide. If the amount of aluminum element is less than 0.01% by weight, its effect is small. On the contrary, if it exceeds 2.0% by weight, the environmental characteristics of the toner, particularly the charging characteristics under high humidity are deteriorated.

Further, the magnetic iron oxide particles used in the present invention have an average particle size of 0.1 to 0.4 μm, preferably 0.1.
It is preferable to have ~ 0.3 μm.

By combining the above-mentioned magnetic iron oxide particles containing silicon element with the polymer component of the present invention having an adjusted acid value, charging characteristics, durability, image characteristics (reproducibility, fog), and other developing characteristics can be obtained. Has been confirmed to improve dramatically. It is considered that this is because "wetting" at the interface between the polymer and the magnetic iron oxide particles was appropriately improved and the dispersibility in the toner was improved.

As a preferred system of the present invention, it is desirable to incorporate the magnetic material having the above-mentioned constitution.

That is, when the toner is made into fine particles such that the weight average particle diameter D ₄ is 3.5 μm ≦ D ₄ ≦ 6.5 μm, the fluidity is deteriorated, and various problems such as blotches and unstable charging are likely to occur. Become. However, by incorporating the magnetic material having the outermost surface composition and structure controlled as described above into the toner, the fluidity is significantly improved, the charging stability is increased, and further the image quality is improved.

The method for measuring various physical property data of magnetic iron oxide particles in the present invention will be described in detail below.

[0193] (1) SiO ₂ amount of magnetic oxide Tetsukaku particle surfaces at the surface SiO ₂ amount present invention of the magnetic iron oxide particles,
Ask for:

That is, 1N NaO was added to 15 g of the sample.
300 ml of H aqueous solution is added and ultrasonically dispersed (10 minutes). Then, the mixture is heated to 50 ° C. and stirred for 30 minutes. afterwards,
The supernatant is separated with a centrifuge (10,000 rpm, 10 minutes).

[0195] 1N-NaOH aqueous solution is added again and ultrasonic dispersion (5 minutes) is carried out, followed by centrifugation. The supernatant is cut off and the solid content is dried. The surface SiO ₂ amount is calculated by measuring and quantifying the sample before and after the alkali cleaning with a fluorescent X-ray analyzer.

(2) Bulk Density The bulk density of the magnetic iron oxide particles in the present invention is JIS-K.
It was measured according to the pigment test method of -5101.

(3) Smoothness In the present invention, the smoothness D of the magnetic iron oxide particles is determined as follows.

[0198]

(Equation 6)

(4) BET Specific Surface Area The BET of magnetic iron oxide particles is actually measured as follows.

[0200] The BET specific surface area is manufactured by Yuasa Ionics Co., Ltd., fully automatic gas adsorption amount measuring device: Autosorb 1
Is used, nitrogen is used as an adsorption gas, and the BET multipoint method is used. The sample pretreatment was 1
Degas for 0 hours.

(5) The average particle diameter and surface area of the magnetic iron oxide particles are measured and the surface area of the magnetic iron oxide is calculated as follows.

A transmission electron micrograph of the magnetic powder was taken,
Of the 40,000-fold enlargement, after arbitrarily selecting 250,
The Martin diameter in the projected diameter (the length of a line segment that bisects the projected area in the fixed direction) is measured, and this is represented by the number average diameter.

For the calculation of the surface area, it is assumed that the magnetic iron oxide is spherical with the average particle diameter as the diameter, and the density of the magnetic iron oxide is measured by a usual method to obtain the surface area value.

(6) Pore distribution The adsorption / desorption isotherm total pore volume of the magnetic iron oxide particles in the present invention with nitrogen gas is determined as follows.

That is, as a measuring device, a fully automatic gas adsorption device: Autosorb 1 (Yuasa Ionics Co., Ltd.)
Manufactured), nitrogen is used as an adsorption gas, and the relative pressure is 0 to
Adsorption 40 points desorption 40 points were measured up to 1.0, and de Boer's t-plot method, kelvin
Formula and B. J. The pore size distribution was calculated by the H method and determined. The sample pretreatment was 10
The time was degassed.

(7) Amount of Silicon Element The amount of silicon element in the magnetic iron oxide particles of the present invention is determined by fluorescent X-ray analyzer SYSTEM3080 (Rigaku Denki Kogyo KK).
(Manufactured by Mitsui Chemicals Co., Ltd.) and in accordance with JIS K0119 “General rules for fluorescent X-ray analysis”.

The magnetic iron oxide particles used in the magnetic toner of the present invention are preferably used in an amount of 20 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 of the present invention include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, Allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilane mercaptan, trimethylsilylmercaptan, Triorganosilyl acrylate,
Examples thereof include vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, and 1,3-diphenyltetramethyldisiloxane.

Examples of the titanium coupling agent include isopropoxy titanium / triisostearate, isopropoxy titanium / dimethacrylate / isostearate,
Isopropoxy titanium / tridodecyl benzene sulfonate, isopropoxy titanium / tris dioctyl phosphate, isopropoxy titanium tri N-ethylaminoethyl aminato, titanium bis dioctyl pyrophosphate oxyacetate, bis dioctyl phosphate ethylene dioctyl phosphite, di n-butoxy / Examples thereof include bistriethanolaminato titanium.

Examples of the organic silicon compound include silicone oil. As a preferable silicone oil, one having a viscosity of about 30 to 1,000 centistokes at 25 ° C. is used, and for example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, fluorine modified. Silicone oil and the like are preferred.

Further, as the coloring material which can be added to the magnetic toner according to the present invention, carbon black, which has been publicly known,
Pigments or dyes such as copper phthalocyanine can be used.

The magnetic toner of the present invention is characterized by containing a charge control agent, and in the case of a negatively chargeable toner, a metal complex salt of a monoazo dye, a metal complex salt of salicylic acid, an alkylsalicylic acid, a dialkylsalicylic acid or a naphthoic acid is used. A negative charge control agent is used.

For example, as the negative charge control agent,

[0215]

Embedded image

[0216]

[Chemical 6]

[0219]

[Chemical 7]

Examples of the more effective negative charge control agent in combination with the magnetic iron oxide used in the present invention include the following three types.

[0219]

Embedded image Monoazo iron complex salt

[0220]

[Chemical 9]

Compounds of an aromatic hydroxycarboxylic acid, aromatic diol or aromatic dicarboxylic acid derivative having the above general formula with an iron atom

[0222]

[Chemical 10]

[Wherein Y¹ And Y² Is a phenyl group, naphthi
R group or anthryl group, R¹And R²Is a halogen source
Child, nitro group, sulfonic acid group, carboxyl group, carbo
Acid ester group, cyano group, carbonyl group, alkyl
A group, an alkoxy group or an amino group, R³And R^FourIs water
Even if it has an elementary atom, an alkyl group, an alkoxy group, or a substituent
A good phenyl group, an aralkyl group which may have a substituent, or
Represents an amino group, R^FiveAnd R⁶Is a hydrogen atom or carbon number 1
~ 8 hydrocarbon groups, k and j are integers 0-3 (same as
Sometimes not 0), and m and n represent 1 or 2.

(Y above¹ , Y² , R¹And R², R³And R^Four,
R^FiveAnd R⁶, K and j, m and n may be the same or different.
Yes. )]

NN′-bisarylurea derivatives having the above general formula

[0226]

[Chemical 11] The monoazo iron complex represented by is preferable.

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

Specific examples of the positive charge control agent include, for example,
Modified products of nigrosine and fatty acid metal salts and the like; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and onium such as phosphonium salts which are analogs thereof. Salts and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (as a laker, phosphotungstic acid,
Phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide,
Ferrocyanides, etc.); metal salts of higher fatty acids, acetylacetone metal complexes; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; diorganotin borate such as dibutyltin borate, dioctyltin borate, dicyclohexyltin borate, etc. These can be used alone or in combination of two or more. Among these, charge control agents such as nigrosine and quaternary ammonium salts are particularly preferably used.

The charge control agent is used in an amount of 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 is preferred.

It is preferable that the magnetic toner of the present invention is mixed with an inorganic fine powder or a hydrophobic inorganic fine powder. For example, silica fine powder or titanium oxide fine powder is preferably used alone or in combination.

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

Further, the silica fine powder used in the present invention is preferably hydrophobized. The hydrophobic treatment is applied by chemically treating with an organic silicon compound or the like that reacts with or physically adsorbs on the silica fine powder. As a preferred method, a method of treating dry silica fine powder produced by vapor phase oxidation of a silicon halogen compound with a silane coupling agent, or simultaneously treating with a silane coupling agent and an organosilicon compound such as silicone oil Is mentioned.

Examples of the silane coupling agent used for the hydrophobic treatment include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyl. Dichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane,
Chlormethyldimethylchlorosilane, triorganosilane mercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldimethyl Examples include siloxane and 1,3-diphenyltetramethyldisiloxane.

Examples of the organic silicon compound include silicone oil. As a preferable silicone oil, one having a viscosity of about 30 to 1,000 centistokes at 25 ° C. is used, and for example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, fluorine modified. Silicone oil and the like are preferred.

As the method for treating silicone oil, for example, silica fine powder treated with a silane coupling agent and silicone oil may be directly mixed by using a mixer such as a Henschel mixer. The method of injecting Alternatively, it may be produced by dissolving or dispersing silicone oil in an appropriate solvent, mixing with silica fine powder of the base, and removing the solvent.

Further, a preferred system for hydrophobizing the silica fine powder used in the present invention is a method prepared by treating with dimethyldichlorosilane, then with hexamethyldisilazane, and then with silicone oil. Can be mentioned.

As described above, it is preferable that the silica fine powder is treated with two or more kinds of silane coupling agents and then treated with an oil because the hydrophobicity can be effectively increased.

Those obtained by subjecting the above-mentioned silica fine powder to a hydrophobizing treatment and further an oil treatment to the titanium oxide fine powder can be used in the present invention, and are preferred similarly to the silica system.

If necessary, external additives other than fine silica powder may be added to the magnetic toner of the present invention.

For example, a charging auxiliary agent, a conductivity-imparting agent, a fluidity-imparting agent, an anti-caking agent, a releasing agent at the time of heat roll fixing,
Resin fine particles or inorganic fine particles that act as a lubricant, an abrasive, etc.

The resin fine particles have an average particle size of 0.
It is preferably from 03 to 1.0 μm, and the polymerizable monomer constituting the resin is styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene, or the like. Styrene monomer, methacrylic acid 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 and phenyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n methacrylate
-Octyl / dodecyl methacrylate / methacrylic acid 2-
Methacrylic acid ester such as ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. Other acrylonitrile, methacrylonitrile,
Examples include monomers such as acrylamide.

As the polymerization method, suspension polymerization, emulsion polymerization,
Soap-free polymerization and the like can be used, but particles obtained by soap-free polymerization are more preferable.

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

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

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

To prepare a magnetic toner for developing an electrostatic image according to the present invention, the polymer component of the present invention and a pigment as a colorant, a dye or a magnetic material, a charge control agent, other additives, etc. are added. Mix well with a mixer such as a ball mill, then melt, knead and knead with a heat kneader such as a heating roll, kneader, extruder to disperse the pigment or dye in the resin to make them compatible with each other. Or dissolve it,
The magnetic toner according to the present invention can be obtained by crushing and solidifying after cooling and solidification.

The magnetic iron oxide containing elemental silicon according to the present invention is produced, for example, by the following method.

Aqueous ferrous salt solution and Fe in the aqueous ferrous salt solution
Magnetite is obtained by bubbling oxygen-containing gas into a ferrous salt reaction aqueous solution containing ferrous hydroxide colloid obtained by reacting 0.90 to 0.99 equivalent of an aqueous alkali hydroxide solution with respect to ^2+. In generating particles, a water-soluble silicate in advance in either of the aqueous alkali hydroxide solution or the ferrous hydroxide colloid containing ferrous hydroxide colloid in terms of silicon element with respect to iron element, the total content ( 0.4 ~
2.0% by weight of 50 to 99%, and 85 to 100 ° C.
While heating in the temperature range of 1, the oxygen-containing gas is ventilated to carry out an oxidation reaction to produce magnetic iron oxide particles containing silicon element from the ferrous hydroxide colloid.
Then, 1.00 equivalent or more of an aqueous alkali hydroxide solution and the remaining water-soluble silicate with respect to Fe ²⁺ remaining in the suspension after the completion of the oxidation reaction, that is, the total content (0.4 to
2.0% by weight) to 1 to 50%, and 85 to 1
While heating in the temperature range of 00 ° C., an oxidation reaction is performed to generate magnetic iron oxide particles containing elemental silicon.

Next, in the case of treatment with aluminum hydroxide, a water-soluble aluminum salt is converted into aluminum particles in terms of aluminum element in the alkaline suspension in which the magnetic iron oxide particles containing the silicon element are generated. After adding 0.01 to 2.0% by weight, the pH is adjusted to the range of 6 to 8 to deposit aluminum hydroxide on the surface of the magnetic iron oxide. Next, the magnetic iron oxide of the present invention is obtained by filtration, washing with water, drying and crushing. Further, as a method of adjusting the smoothness and the specific surface area within the preferred ranges of the present invention, it is preferable to use a mix muller or a raker machine or the like to perform compression, shearing and lapping.

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

The water-soluble aluminum salt to be added is exemplified by aluminum sulfate and the like.

As the ferrous iron salt, iron sulfate generally produced as a by-product in the production of titanium by the sulfuric acid method, iron sulfate produced as a by-product when the surface of a steel sheet is washed can be used, and further iron chloride or the like can be used. .

[0253]

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

[Production Example 1 of Resin Composition] Synthesis of Low Molecular Weight Polymer (L-1) 300 parts by weight of xylene was put into a four-necked flask, and the inside of the container was sufficiently replaced with nitrogen while stirring. The temperature is raised to reflux.

Under this reflux, a mixed solution 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. After that, the mixture was held for 2 hours to complete the polymerization, and a low molecular weight polymer (L-1) solution was obtained.

A portion of this polymer solution was sampled,
Low molecular weight polymer (L-1) obtained by drying under reduced pressure
GPC and glass transition point (Tg) were measured, and weight average molecular weight (Mw) = 9,600, number average molecular weight (Mn) = 6,000, peak molecular weight (PMw) =
It was 8,500, Tg = 62 ° C., and the acid value was 23.

At this time, the polymer conversion rate was 97%.

Synthesis of high molecular weight polymer (H-1) 180 parts by weight of degassed water and 20 parts by weight of 2% by weight aqueous solution of polyvinyl alcohol were placed in 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).
tert-Butylperoxycyclohexyl) propane (half-life 10 hours, temperature; 92 ° C.) (0.1 parts by weight) was added and the mixture was stirred to give a suspension.

After thoroughly replacing the inside of the flask with nitrogen,
The temperature was raised to 5 ° C to initiate polymerization. After holding at the same temperature for 24 hours, 0.1 part by weight of benzoyl peroxide (half-life: 10 hours, temperature: 72 ° C.) was added additionally. Furthermore, it hold | maintained for 12 hours and superposition | polymerization was completed.

After the completion of the reaction, a NaOH aqueous solution having an acid value (AV = 7.8) of 6 times the obtained high molecular weight polymer (H-1) was added to the suspension, followed by stirring for 2 hours. It was

The high molecular weight polymer (H-1) was separated by filtration, washed with water, dried, and analyzed. Mw = 1.8 million, P
The Mw was 1.2 million, the Tg was 62 ° C., and the acid value was 6.

Production of Binder: In a four-necked flask, 100 parts by weight of xylene, 25 parts by weight of the above 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 carry out preliminary dissolution. After maintaining in this state for 12 hours, a uniform preliminary solution (Y-1) of the polymer (H-1) and polypropylene was obtained.

A portion of this preliminary lysate was sampled,
When it was dried under reduced pressure and the glass transition point of the obtained solid content was measured, it was 61 ° C.

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

The above preliminary 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 then pulverized. A resin composition (I) for toner was obtained.

When the resin composition (I) was analyzed, P
Mw = 1.1 million, Tg = 62.5 ° C., and THF insoluble matter was 2.1% by weight.

[Production Examples 2, 3, 5, 8 of Resin Composition]
9] In the same manner as in Production Example 1 of resin composition, the amount of monobutyl maleate, styrene, n-butyl acrylate and the amount of initiator were adjusted to give low molecular weight polymers L-2, L-3, L-4, L.
-6, L-7 were obtained and the high molecular weight polymer H-1 was blended in a predetermined amount to prepare resin compositions II, III, V, VIII and IX.
I got

[Production Example 4 of resin composition] In the same manner as in Production Example 1 of resin composition, the amounts of monobutyl maleate, styrene, n-butyl acrylate and the amount of initiator were adjusted to prepare a high molecular weight polymer H-2. And a low molecular weight polymer L-1 was blended in a predetermined amount to obtain a resin composition IV.

[Production Examples 6 and 7 of Resin Composition] The resin composition VI having the physical properties shown in Table 1 was prepared in the same manner as in Production Example 1 of resin composition.
VII was obtained.

Table 1 shows the physical properties of each polymer.

[0271]

[Table 1]

Next, a production example of the magnetic iron oxide used in the present invention will be shown.

(Production Example 1 of Magnetic Iron Oxide Particles) An aqueous solution of ferrous sulfate was mixed with 0.95 equivalent of an aqueous solution of sodium hydroxide with respect to Fe ²⁺ , and then Fe (OH) ₂ was added. An aqueous solution of monoiron salt was produced.

Then, sodium silicate was added to the iron element so as to be 1.0% in terms of silicon element. Next, magnetic iron oxide particles containing elemental silicon were generated by aerating the aqueous ferrous salt solution containing Fe (OH) ₂ with air at a temperature of 90 ° C. to cause an oxidation reaction.

Further, to this suspension, sodium silicate 0.1%
An aqueous sodium hydroxide solution in which (iron element converted to silicon element) is added in an amount of 1.05 equivalent to the residual Fe ²⁺ , and further heated at a temperature of 90 ° C. to 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 agglomerated magnetic iron oxide particles are crushed (consolidation crushing by a mix muller),
Magnetic iron oxide particles a having the properties shown in Table 2 were obtained. The particle size was 0.21 μm.

(Production Examples 2 and 3 of Magnetic Iron Oxide Particles) Magnetic iron oxide was produced in the same manner as in Production Example 1, and a predetermined amount of aluminum sulfate was added to the slurry liquid before the filtration step after completion of the reaction to adjust the pH. Was adjusted to a range of 6 to 8 and the surface treatment of the magnetic iron oxide was performed as aluminum hydroxide to obtain magnetic iron oxide particles b and c of Production Examples 2 and 3. The characteristics are shown in Table 2.

(Production Examples 4 and 5 of Magnetic Iron Oxide Particles) A predetermined total silicon content was added at the time of the reaction in the first step of Production Example 1 and the pH adjustment was changed to obtain the magnetic oxidation of Production Examples 4 and 5. Iron particles d and e were obtained. The characteristics are shown in Table 2.

(Production Example 6 of Magnetic Iron Oxide Particles) A predetermined total silicon content was added during the reaction in the first step of Production Example 1, and the amount of the sodium hydroxide aqueous solution added was more than 1 equivalent to Fe ^2+. By changing the amount and adjusting the pH, magnetic iron oxide particles f of Production Example 6 were obtained. The characteristics are shown in Table 2.

(Production Examples 7 and 8 of Magnetic Iron Oxide Particles) At the time of the reaction in the first step of Production Example 1, a predetermined total silicon content was added, and further, the aqueous sodium hydroxide solution to be added was 1 to Fe ^2+. Magnetic iron oxide particles g and h of Production Examples 7 and 8 were obtained by changing the pH adjustment to an amount exceeding the equivalent amount. The characteristics are shown in Table 2.

[0281]

[Table 2]

Example 1 Resin composition (I) 100 parts by weight Magnetic iron oxide a 100 parts by weight Negative charge control agent (the following formula) 2 parts by weight

[0283]

[Chemical 12]

The above mixture was melt-kneaded with a twin-screw extruder heated to 140 ° C., the cooled kneaded product was coarsely pulverized with a hammer mill, and the coarsely pulverized product was finely pulverized with a jet mill. Was classified with a fixed wall type air classifier to produce classified powder. Further, the obtained classified powder is subjected to strict classification of ultrafine powder and coarse powder at the same time with a multi-division classifier (Elbowjet classifier manufactured by Nittetsu Mining Co., Ltd.) utilizing the Coanda effect to obtain a volume average particle diameter (D _V ). A negatively chargeable magnetic toner having a thickness of 4.3 μm and a weight average particle diameter (D ₄ ) of 5.1 μm was obtained.

100 parts by weight of this magnetic toner and 1.2 parts by weight of hydrophobic silica fine powder (BET 300 m ² / g) which was treated with dimethyldichlorosilane, then with hexamethyldisilazane, and then with dimethyl silicone oil. , And 0.08 part by weight of styrene-acrylic fine particles (average particle size: 0.05 μm) obtained by soap-free polymerization were mixed with a Henschel mixer to prepare a magnetic developer (toner No. A).

[Examples 2 to 9] Resin composition I of Example 1
Were changed to resin compositions II to IX, respectively, and magnetic developers were obtained in the same manner as in Example 1 (toners No. B to I). The obtained toner physical property values are shown in Tables 3 and 4.

[Examples 10 to 16] The magnetic iron oxide a of Example 1 was changed to the magnetic iron oxides b to h to obtain magnetic developers as in Example 1 (toner Nos. J to P).

Example 17 A toner A2 was prepared in the same manner as in Example 1 except that the negative charge control agent in Example 1 was changed to 0.6 part by weight of the following chromium complex compound.

[0289]

[Chemical 13]

Comparative Example 1 A magnetic developer having different particle diameters was obtained by adjusting the conditions of the classifying device during classification with the multi-division classifying device of Example 1 (toner No. Z). The physical properties of the toner (GPC, molecular weight distribution, THF insoluble content) were almost the same as those of Toner A.

[0291]

[Table 3]

[0292]

[Table 4]

The above one-component magnetic developer was applied to a laser beam printer LBP-8II (using an OPC photosensitive drum) manufactured by Canon Inc. at 8 sheets / minute to 16 sheets / minute and a resolution of 600.
Image was evaluated by using a remodeling machine which was remodeled into a dpi and further incorporated with the transfer device shown in FIG. The process speed at this time is 90 mm / sec. Met.

The conditions of the transfer roller are as follows: surface rubber hardness of the transfer roller 27 °, transfer current 1 μA, transfer voltage +
The contact pressure was 2000 V and the contact pressure was 50 [g / cm]. The conductive elastic layer of the transfer roller is made of EP in which conductive carbon is dispersed.
It was formed of DM and had a volume resistance of 10 ⁸ Ω · cm.

In this embodiment, the charging roller shown in FIG. 2 was used for the primary charging. The outer diameter of the charging roller 42 is 12 mmφ, and the conductive rubber layer 42b has an EPD.
For the M and the surface layer 42c, a nylon resin having a thickness of 10 μm was used. The hardness of the charging roller 42 is 54.5 ° (AS
KER-C). E is a power source for applying a voltage to the charging roller 42, and supplies a predetermined voltage to the core metal 42a of the charging roller 42. In FIG. 2, E indicates a system in which an AC voltage is superimposed on a DC voltage. The conditions were as described above.

Further, the magnetic blade as one of the charging members was modified to an elastic blade made of urethane rubber which was in contact with the developing sleeve.

The primary charge is -700 V, a gap is set in a non-contact manner between the photosensitive drum and the developer layer on the developing drum (including magnet), and an AC bias (f = 1,800 Hz, Vpp) is set.
= 1,600 V) and DC bias (V _DC = -500)
V) is applied to the developing drum while _VL is -170V.
And develop by electrostatic charge image to OPC magnetic toner image
It was formed on the photoreceptor.

The formed magnetic toner image was transferred onto plain paper at the above-mentioned positive transfer potential, and the plain paper having the magnetic toner image was fixed on the plain paper through a heating and pressure roller fixing device.

At this time, the surface temperature of the heating roller of the heating and pressure roller fixing device was set to 180 ° C., the total pressure between the heating roller and the pressure roller was set to 5.5 kg, and the nip was set to 4 mm.

Under the above setting conditions, normal temperature and normal humidity (25 ° C., 6
Under the environment of 0% RH, a printout test was conducted continuously on 20,000 sheets continuously while supplying a developer at a printing speed of 16 sheets (A4) / min, and the obtained images were evaluated for the following items.

Similarly, in a high temperature and high humidity environment (32.5 ° C.,
85% RH) and low temperature and low humidity environment (15 ℃, 10% R)
The image drawing test was performed in H). The print mode is 2 sheets / 20 sec. And

In a high temperature and high humidity environment, 4000
After performing the printout test, in the same environment, 2
It was left for one day, and the test of printing 4000 sheets was further conducted.

(1) Image density 10,000 on ordinary plain paper for copiers (75 g / m ² ).
The evaluation was made by maintaining the image density at the end of printing one sheet. The image density was measured by using a "Macbeth reflection densitometer" (manufactured by Macbeth Co., Ltd.) to measure the relative density with respect to a printout image of a white background portion having a document density of 0.00.

(2) Fog Fog was calculated by comparing the whiteness of the transfer paper measured with a reflectometer (manufactured by Tokyo Denshoku Co., Ltd.) and the whiteness of the transfer paper after printing solid white. The environment is low temperature and low humidity (15 ° C, 10% RH), and the print mode is 2
Sheet / 20 sec. And

(3) Image Quality (Dot Reproducibility) The reproducibility of the minute diameter isolated 1 dot as shown in FIG.

◎: Very good ○: Good △: Normal ×: Somewhat bad

(4) Fixability The fixability was evaluated by rubbing the fixed image with a soft thin paper under a load of 50 g / cm ² and the reduction rate (%) of the image density before and after the rubbing. In addition, as the environment, under low temperature and low humidity (1
It was carried out at 5 ° C. and 10% RH).

⊚ (excellent): 5% or less, ◯ (good): 5% or more and less than 10% △ (possible): 10% or more, less than 20%, × (impossible): 20% or more

(5) 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.

⊚: Very good (not generated), ◯: Good (nearly generated) Δ: Practical, ×: Not usable (slightly generated) (Stains remarkably on the image)

On the other hand, after the printout test was completed, the state of sticking 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 (hardly generated) Δ: Practical (possible sticking but little influence on the image) X: Not practical (sticking is large and image unevenness occurs) Occur)

Similarly, the state of occurrence of scratches on the surface of the photosensitive drum and the adhesion of residual toner and the influence on the printout image were evaluated visually.

⊚: Very good (not generated) ◯: Good (slightly scratches are seen, but does not affect the image) Δ: Practical (with sticking or scratches, but the image is not affected) X): Practical use (many fixed, causing vertical stripe-shaped image defects)

(6) Aggregation degree The aggregation degree of the toner is measured as follows.

Weigh 5 g of toner. Powder tester (Hosokawa Micron Co., Ltd.) from the top 60 mesh, 100
Set the sieves in 3 steps in the order of mesh, 200 mesh, and gently place 5 g of the sample weighed on the sieve,
Vibration with an amplitude of 0.15 mm is applied for 15 seconds, the weight of the toner remaining on each sieve is measured, and the degree of aggregation is calculated according to the following formula.

[0317]

(Equation 7) The above results are summarized in Table 5.

[0318]

[Table 5]

[0319]

As described above, according to the present invention, by adjusting the molecular weight distribution of the polymer component and the acid value of the low molecular weight component and the high molecular weight component in the fine particle toner composition, the fluidity and the charging stability can be improved. Improvement is possible, and the crushability is good and the crushed particle size is sharp. Further, it enables lower temperature fixing than that of the conventional one, has excellent offset resistance, and enables dot reproducibility, fog reduction, and long-term durability. Further, even when it is applied to speeding up of the apparatus, long-term charge stability is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a transfer device.

FIG. 2 is a diagram showing an outline of a charging roller.

FIG. 3 Isolation 1 for testing the development properties of magnetic toners
It is an explanatory view of dot.

[Explanation of symbols]

 1 Latent Image Carrier (Photoreceptor) 2 Transfer Roller 2a Core Bar 2b Conductive Elastic Layer 3 Constant Voltage Power Supply 42 Charging Roller

[Procedure amendment]

[Submission date] July 5, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0290

[Correction method] Change

[Correction content]

Comparative Example 1 A magnetic developer having different particle diameters was obtained by adjusting the conditions of the classifying device during classification with the multi-division classifying device of Example 9 (toner No. Z). The physical properties of the toner (GPC, molecular weight distribution, THF insoluble content) were almost the same as those of Toner I.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0291

[Correction method] Change

[Correction content]

[0291]

[Table 3]

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0292

[Correction method] Change

[Correction content]

[0292]

[Table 4]

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0318

[Correction method] Change

[Correction content]

[0318]

[Table 5]

Front page continued (72) Inventor Hiroshi Yusa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Innovator Naoki Kobori 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Koichi Tomiyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Keita Nozawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (22)

[Claims] 1. A magnetic toner comprising magnetic toner particles containing at least a polymer component, a magnetic material and a charge control agent, and an inorganic fine powder, the weight average diameter (D) of the magnetic toner.
₄ ) is X (μm), and the ratio of toner particles having a particle diameter of 3.17 μm or less in the number distribution of magnetic toner is Y (number%), the following condition −5X + 35 ≦ Y ≦ −25X + 180 (1) 3. 5 ≦ X ≦ 6.5 (2) The magnetic toner has a particle size distribution satisfying (2), the polymer component is a) substantially free of THF insoluble matter, and b) the THF soluble content of the polymer component. In the chromatogram of gel permeation chromatography (GPC), the main peak is in the region of molecular weight 3 × 10 ^{3 to} 3 × 10 ⁴ , and the subpeak or shoulder is in the region of molecular weight 1 × 10 ^{5 to} 3 × 10 ^6. And c) the acid value (A _VL ) of the low molecular weight polymer (region of molecular weight less than 5 × 10 ⁴ in GPC chromatogram) is higher than that of the high molecular weight polymer (molecular weight 5 × 1 in GPC chromatogram).
A magnetic toner having an acid value (A _VH ) of 0 ⁴ or more). 2. The ratio Y / Z of the ratio Y of particles of 3.17 μm or less in the number particle size distribution of the magnetic toner and the ratio Z of particles of 3.17 μm or less in the volume particle size distribution is 2.0.
The magnetic toner according to claim 1, wherein the magnetic toner has a particle size of ˜8.0. 3. The volume particle size distribution of the magnetic toner is 8
The magnetic toner according to claim 1, wherein the volume ratio of the particles having a size of μm or more is 10% by volume or less. 4. A low molecular weight polymer as a polymer component of the magnetic toner (having a molecular weight of 5 × 10 ⁴ in a GPC chromatogram).
An acid value A _VL is 10~35mgKOH / g less than the area), the acid value A _VH of the high molecular weight polymer (molecular weight 5 × 10 ⁴ or more regions in the GPC chromatogram) is 0.5 to 1
The magnetic toner according to claim 1, wherein the magnetic toner is 1 mgKOH / g. 5. The glass transition temperature (Tg) of the magnetic toner
Claim 1 but which is 50-70 ° C., and the relationship of Tg _H of Tg _L and a high molecular weight polymer having a low molecular weight polymer of the magnetic toner being in the range of Tg _L ≧ Tg _H -5 The magnetic toner described in 1. 6. a Tg of 55 to 65 ° C. of the magnetic toner, and the relationship of Tg _L and Tg _H of the high molecular weight polymer having a low molecular weight polymer of the magnetic toner is in a range of Tg _L ≧ Tg _H The magnetic toner according to claim 1, wherein: 7. In the polymer component of the magnetic toner, the low molecular weight polymer has an acid value A _VL of 21 to 35 mgKOH / g, and the high molecular weight polymer has an acid value A _VH of 0.5 to 11 mgK.
The magnetic toner according to claim 1, wherein the magnetic toner is OH / g. 8. The polymer component of the magnetic toner, wherein the difference in acid value A _VL −A _VH between the low molecular weight polymer and the high molecular weight polymer is 10 ≦ (A _VL −A _VH ) ≦ 27. The magnetic toner according to claim 1 or 7. 9. The magnetic toner according to claim 1, wherein a polymer component of the magnetic toner satisfies the following formula. [Equation 1] 10. The magnetic toner according to claim 1, wherein both the low molecular weight and high molecular weight polymer components of the magnetic toner contain at least 65 parts by weight of a styrene monomer component. 11. The magnetic toner according to claim 1, wherein the high molecular weight polymer component of the magnetic toner is a polymer polymerized with a polyfunctional polymerization initiator. 12. The high molecular weight polymer component of the magnetic toner is a polymer polymerized by using at least a polyfunctional polymerization initiator and a monofunctional polymerization initiator in combination. The magnetic toner described. 13. The magnetic toner according to claim 1, wherein the magnetic substance is magnetic iron oxide particles, and the magnetic iron oxide particles contain elemental silicon. 14. The magnetic toner according to claim 13, wherein the content of silicon element in the magnetic iron oxide particles is 0.1 to 2.0% by weight based on the iron element. 15. The magnetic iron oxide particles have Si on the surface thereof.
14. The magnetic toner according to claim 13, wherein 0.01 to 1.00% by weight of silicon oxide in terms of O ₂ is present. 16. The smoothness of the magnetic iron oxide particles is 0.3 to.
The magnetic toner according to claim 13, wherein the magnetic toner is 0.8. 17. The magnetic iron oxide particles have a bulk density of 0.8 g.
14. The magnetic toner according to claim 13, wherein the magnetic toner has a density of at least ³ / cm ³ . 18. The specific surface area of the magnetic iron oxide particles is 15.
14. The magnetic toner according to claim 13, wherein the magnetic toner is 0 m ² / g or less. 19. The magnetic toner according to claim 13, wherein the magnetic iron oxide particles are treated with 0.01 to 2.0% by weight of aluminum hydroxide as an aluminum element. 20. The magnetic toner according to claim 13, wherein the magnetic iron oxide particles have a total pore volume of 7.0 × 10 ^{−3 to} 15.0 × 10 ⁻³ ml / g. . 21. The charge control agent is represented by the following general formula: The magnetic toner according to claim 1, which is represented by: 22. The charge control agent is represented by the following general formula: The magnetic toner according to claim 1, which is represented by: